Subscribe Now Subscribe Today
Review Article
 

Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters



Neeraj K. Sethiya
 
Facebook Twitter Digg Reddit Linkedin StumbleUpon E-mail
ABSTRACT

'Gut health' is a term currently gaining much more attentions in veterinary literature especially in poultry. It covers multiple positive aspects of the gastrointestinal (GI) tract, such as the effective digestion by absorption of food, absence of GI illness, normal and stable intestinal microbiota, effective immune status and a state of well-being. Any disturbance or imbalance in above said aspects may influence the gut health. Thus it is necessary to maintain the balance of all possible associated factors related to gut health. Although till date this is being achieved in poultry farming by Antibiotic Growth Promoters (AGPs). However, the growing concern over the transmission and the proliferation of resistant bacteria in human via the food chain has led to a ban of Antibiotic Growth Promoters (AGP) in livestock feed within the European Union since, 2006. As a result, new commercial additives derived from nature have been examined as part of alternative feed strategies for the future. Such products have several advantages over commonly used commercial antibiotics since they are residue free and recognized as safe items in the food industry. Certain natural alternatives recognized by scientific community as Natural Growth Promoters (NGPs) to preserve and maintain the balance of gut microbiota in poultry are summarized in present communication. The article is also enriched with possible mechanisms of action of NGPs with relevant examples by citing research results obtained by various authors in past and current years.

Services
Related Articles in ASCI
Search in Google Scholar
View Citation
Report Citation

 
  How to cite this article:

Neeraj K. Sethiya , 2016. Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters. Asian Journal of Poultry Science, 10: 1-29.

DOI: 10.3923/ajpsaj.2016.1.29

URL: https://scialert.net/abstract/?doi=ajpsaj.2016.1.29
 
Received: September 14, 2015; Accepted: October 21, 2015; Published: December 04, 2015



INTRODUCTION

The term ‘gut health’ is currently gaining much more attentions in veterinary literature especially in poultry and has been applied to coordinate the working efficiency of gut (Cummings et al., 2004; Laudadio et al., 2012). Although, the term is restricted to gastro-intestinal (GI) tract only and does not involve other organs (Bischoff, 2011). The gut is the primary site for multitude of processes such as, digestion, fermentation, nutrient absorption, nutrient metabolism, intestinal integrity, immune recognition, immune regulation and development of immune tolerance (Sommer and Backhed, 2013). Gut is mainly composed of physical, chemical, immunological and microbiological components and acts as a selective barrier between the tissues of the bird and its luminal environment (Yegani and Korver, 2008). The gut is the most extensive exposed surface and is constantly exposed to wide variety of potentially beneficial non-infectious as well as harmful infectious agents (Lievin-Le Moal and Servin, 2006). It has been reported that exposure of gut to such harmful infectious agents or pathogens cause an imbalance, which can lead to severe productivity loss, sudden dietary changes, intestinal disease (worm infestation, coccidiosis) and immune suppression (McDevitt et al., 2006). It is now well established that development of antibiotic resistance result from the use of Antibiotic Growth Promoters (AGPs) in animal feed, may be compromised the efficacy of similar antibiotics in therapy for human diseases. Hence, the European Union (EU) introduced a ban on AGPs in 2006, which is now followed in most of the other nations. Before the ban, gut of poultry was highly dependent on Antibiotic Growth Promoters (AGPs) to control intestinal pathogens (Wallace et al., 2010). In view of rising concerns on the extensive loss in poultry due to GI complaints and implementation of strict laws to use of harmful synthetic drug or antibiotics, creates demand of an alternative disease control resources to enhance gut health and to reduce the use of AGPs (Mirzaei-Aghsaghali, 2012). Interest and some useful research on various Natural Growth Promoters (NGPs) such as phytobiotics (essential oils, powders, extracts and phytochemicals), probiotics, prebiotics, synbiotics, organic acid, clay minerals, egg yolk antibodies, exogenous enzymes, recombinant enzymes, nucleotides, polyunsaturated fatty acids and miscellaneous compounds has increased the impetus for revisiting to look for new, useful additives that can enhance gut health and productivity of birds. Utilization of such Natural Growth Promoters (NGPs), as an alternative to AGPs are summarised and explored in the present work by reviewing all possible updated literature till date.

NGPs in poultry gut health: Many alternative substances obtained from nature and belonging to the groups of prebiotics, probiotics, organic acids, enzymes, silicates, herbs and spices etc., have been vigorously tested and evaluated for their potential to replace AGPs in poultry diets (Panda et al., 2006; Khan et al., 2012a, b). Such, alternative substances were referred as Natural Growth Promoters (NGPs). There are a number of such investigated NGPs that are mainly utilised for providing beneficial role for improving health of poultry against various infectious diseases rather than regular nutrition. The involvement of these NGPs in improving of intestinal morphology and nutrient absorption may also encourage the scientists to include these compounds in the diet to improve gut health, promote the growth and overall performance of birds.

Characteristics of ideal NGPs for gut health: Ideally, the NGPs alternatives to AGP should have the same beneficial actions as AGP. Some of key features identified from the most well-known hypothesized mechanism of AGPs to be fulfilled by proposed NGPs (Huyghebaert et al., 2011) that favours performance of gut are: (1) Antimicrobial action, (2) Reduces the incidence and severity of subclinical infections, (3) Reduces the microbial use of nutrients, (3) Improve absorption of nutrients, (4) Reduces the amount of growth-depressing metabolites, (5) Control microbiota shifts, (6) Inhibit the production and excretion of cytokines by immune cells (macrophages) and (7) Shifting the microbiota composition towards one that is less capable of evoking an inflammatory response (Humphrey and Klasing, 2003). Based on the suggested mechanism of action of none of the non-antibiotic NGPs is likely to compensate the loss of gut health. So, it must be emphasised that some strategies will only help to compensate partially by NGPs and will work through indirect mechanisms.

NGPs and their mode of action
Phytobiotics or botanical supplements:
Many plants have been reported to possess beneficial multifunctional properties and have been used as feed additives for farm animals in ancient cultures for the same length of time as for human (Huyghebaert et al., 2011). There are many categories of plants products on the basis of physical characters and appearance viz., essential oil, crude or processed plant parts, processed extracts, mixtures of powders or extracts and phytochemicals used for the prevention and treatment of various diseases in farm animals (Sethiya et al., 2013; Dhama et al., 2015). Botanical or herbal extracts, flavours and essential oils (EO) are now fall within the scope of European Commission Regulation 1831/2003. However, unprocessed herbs are still regarded as feed materials and do not need any authorisation (Huyghebaert et al., 2011).

Essential oils: Essential oils are also known as volatile or ethereal oil, obtained from medicinal and aromatic plant materials, which have the characteristic odor or flavor of source plant and are mainly associated for essences and fragrances of plants (Stein and Kil, 2006; Tomer et al., 2010). The major actions exhibited by essential oils are: to increase the release of digestive enzymes and reduce the amount of nutrients available for the growth of bacteria in the lumen of gut (Pasteiner, 2006). The antimicrobial properties of EO have not been fully established but the majority of them shown their effect by changing in lipid solubility at the surface by hydrophobic constituents, which may rupture or disintegrate the outer membrane of bacteria (Dorman and Deans, 2000). A summary of promising EO proven to as a possible sources of NGPs have been shown in Table 1.

Botanicals powder and extracts: Plant-derived products are natural, less toxic, residue free and have been scientifically proven as ideal feed additives in food animal production due to presence of varying degree of growth promoting nutraceuticals components (Wang et al., 1998). The various research conducted to understand the proposed mechanisms by which the botanicals powder and extract mainly exert their beneficial effects are as follows: (1) Disrupt cell membrane of microbes, (2) Interfere with virulence properties of the microbes by increasing the hydrophobicity, which may influence the surface characteristics of microbial cells, (3) Stimulates and proliferate the growth of beneficial bacteria (e.g., lactobacilli and bifidobacteria) in the gut, (4) Act as an immunostimulants, (5) Protects intestine from microbial attack, (6) Stimulate the proliferation and growth of absorptive cells (villus and crypt) in the gastrointestinal tract and (7) Enhances the production and/or activity of the digestive enzymes (Jamroz et al., 2003; Vidanarachchi et al., 2006). Table 2 shows some examples of botanicals powder and extracts with their growth promoting effects on the gut.

Phytochemicals: Phytochemicals are purified single chemical compounds (primary and secondary metabolites) present in cell sap of the naturally occurring plants and may possess some biological significance (Sethiya et al., 2009). The primary mode of action of phytochemicals is to have a significant action on growth inhibition of harmful intestinal microflora in the GI tract. They likely to promote growth by stimulating function of digestive enzymes and organ, e.g., pancreas and small intestine. Changing permeability for cations such as H+ and K+ ions of microbial cell membranes of microorganisms, exhibit growth promotion by oxidation-resistant activity and improvement of the immune system are major proposed mechanisms reported by various researchers by which the phytochemicals exert their antimicrobial activity. A summary of recent update on the effect of some examples of phytochemicals on gut health, in chickens was shown in Table 3.

Table 1:Essential oils and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

Table 2: Medicinal plants powders/ extract/combinations and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

Table 3:Phytochemicals and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

Probiotics: Probiotics are strains of various microbial species, currently has been gained attention as a substitute of antibiotics for poultry production as growth promoters with feed additives (Ahmad, 2006). The various proposed mechanisms by which probiotics act to maintain a beneficial microbial population are: (1) Promote balance of bacteria in the gut by competitive exclusion and antagonism, (2) Involved in gut maturation and integrity, (3) Immune enhancement and preventing inflammation use (4) Improves digestive enzyme activity, (5) Improves feed intake and digestion, (6) Neutralise enterotoxins, (7) Stimulates immune response and (8) Act as growth stimulator (Jin et al., 1997; Simon et al., 2001). Table 4 summarize some examples of probiotic strains and their effects on the gut microbial population of the chicken.

Prebiotics: Prebiotic has been defined as "a non-digestible dietary supplement or feed ingredient that beneficially affects the host by selectively stimulating the growth by altering the composition and metabolism of the gut microbiota" (Gibson and Roberfroid, 1995).

Table 4:Probiotics and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

The proposed mechanism by which prebiotics exert their effects are: (1) Growth inhibition of harmful intestinal microbes (through competition for substrates and mucosal attachment sites), (2) Increased intestinal acidity (through production of short-chain fatty acids), (3) Growth stimulation of intestinal absorptive cells and (4) Stimulation of the enteric immune system, thus facilitating better performance and health status of the birds (Gibson and Roberfroid, 1995; Collins and Gibson, 1999; Huyghebaert et al., 2011; Chen et al., 2014). Table 5 summarize some examples of prebiotic and their effects on the gut microbial population of the chicken.

Synbiotics: Synbiotic has been defined as "any combination, which is formed by adding both probiotics and prebiotics to provide the beneficial effects on the gut of birds" (Huyghebaert et al., 2011). This combination could improve the survival and persistence of the health-promoting organism in the gut of birds and can be utilised as alternative to AGP due to its availability as a specific substrate for fermentation and having synergistic action of both probiotics and prebiotics (Yang et al., 2009; Adil and Magray, 2012; Aziz Mousavi et al., 2015). Table 6 summarize some examples of synbiotics with their potential benefits on the intestinal microbial ecosystem of chicken.

Organic acids: Organic acids are group of organic chemicals, composed of carboxylic acid, including fatty acids and amino acids, of the general structure R-COOH (Dibner and Buttin, 2002). In recent years, the use of organic acid has been increased many fold due to its potential to reduce many pathogenic and spoilage organisms by lowering the gut pH (Huyghebaert et al., 2011).

Table 5:Prebiotics and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

Table 6:Synbiotics and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

Table 7:Organic acids and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

They lower the pH, at which the activity of proteases and beneficial bacteria is optimized and proliferation of pathogenic bacteria is minimised by a direct antibacterial effects destroying their cell membranes (Partanen and Mroz, 1999; Chowdhury et al., 2009). Table 7 summarize some examples of organic acids and their effects on the gut microbial population of the birds.

Clay minerals: Clay minerals are natural clay formed by a net of stratified tetrahedral or octahedral layers and mainly composed by molecules of silicon, aluminum and oxygen (Vondruskova et al., 2010). Clays added to the diet can bind and immobilize toxic materials such as aflatoxins and heavy metals etc., may present in the gastrointestinal tract of chicken and thus, reduce toxicity (Owen et al., 2012). As a result of their binding properties, clay minerals have been widely used in poultry diets to improve chicken performance when diets are supposed to contain mycotoxins (Zhou et al., 2014). Some of the molecules of clay minerals such as, bentonites, zeolite, kaolin, montmorillonite, smectite, illite, kaolinite, biotic and clinoptilolite, etc., have been reported to exhibit beneficial effects on the intestinal health of chicken due to additional toxin binding action (Thacker, 2013).

Egg yolk antibodies: Egg yolks antibodies (IgY) are find its application as a potential alternative to antibiotics for growth promotion and have ability to neutralise specific pathogens of gut (Thacker, 2013). In order to produce these antibodies, hens are exposed (usually injected) to antigens of choice to induce desirable immune responses. Normally, these antibodies are then transferred to the egg yolk. Booster dose of immunisation (second exposure) is usually given at a later time to ensure the continued transfer of antibodies from hen to the egg yolk. These antibodies are then extracted from the egg yolk and further processed to be administered directly to the animal or included in the feed (Schade et al., 2005).

Exogenous enzymes: Exogenous enzymes including â-glucanase, xylanase, amylase, ⟨-galactosidase, protease, lipase, phytase, etc., have been supplemented in poultry diets and reported to modulate the gut microbiota of birds (Adeola and Cowieson, 2011). The effects of enzymes on gut microflora were classified into two phases: an ileal phase and a caecal phase. In the ileum, enzymes simply reduce the number of bacteria by increasing the rate of digestion and limiting the amounts of substrates available to the microflora. While, in the caecal phase enzymes produce soluble, poorly absorbed sugars which feed beneficial bacteria. However, the effects of enzymes on the gut microflora may be far more than those two phases (Bedford and Cowieson, 2011).

Recombinant enzymes: The application of genetic engineering allows us to develop targeted enzymes at molecular level for specific purposes. Recently, several enzymes have been developed, which have considerable potential for animal feed application (He et al., 2010). These enzymes have special properties such as, active over a broad pH range, exhibit thermostability, resistant to pepsin and trypsin and viable under simulated gastric conditions. Some typical example includes inclusion of a recombinant carbohydrases and â-mannanase in corn soybean meal diets cause magnitude of the improvement (Pettey et al., 2002).

Nucleotides: Nucleotides are essential components of body involves in cellular metabolism and all intracellular biochemical processes such as, biosynthetic pathways, energy transfer system, as co-enzyme components and as well as biological regulators. Nucleotides alter the cellular lipid metabolism, particularly of long-chain polysaturated fatty acids and the lipoprotein synthesis. Nucleotides changes the composition of intestinal microflora that affect long-chain polyunsaturated fatty acids levels, as some bacteria’s possess necessary enzymes for fatty acid elongation and denaturation and also promote intestinal absorption of iron by conversion of purine nucleotides (AMP, GMP) to inosine, hypoxanthine and uric acid which increase the absorption of iron (Cosgrove, 1998).

Polyunsaturated fatty acids: Polyunsaturated fatty acids (PUFAs) are lipids in which the constituent hydrocarbon chain possesses two or more carbon-carbon double bonds, such as en-3 and n-6 fatty acids which were found to be essential components for the immune function of body’s. Fish oil and corn oil are the main source of feed additive in poultry, contain n-3 and n-6 type polysaturated fatty acids. There are various reports which reflect the utility of these oil for improving gut and overall immunity of the poultry. In another study combination of tuna oil, sunflower oil and palm oil (contain n-3 PUFAs) improves immune responses of birds, as evidenced by the increase in spleen weight, Infectious Bronchitis Disease (IBD), Newcastle Disease (ND), antibody titres, IL-2 and IFN-concentrations (Maroufyan et al., 2012). Conjugated linoleic acid (CLA) is another type of PUFA that has been used as feed supplement to poultry diets and reported for enhancing the immune response, growth of immune tissue, stimulated T-lymphocyte proliferation, elevate, antibody production and maintain the number of LAB in the gut of chicken (He et al., 2007).

Miscellaneous compounds: Many additional compounds have been tested and reported in animals such as spray-dried porcine plasma, yeast culture, bacteriophages, lysozyme, bovine colostrum, lactoferrin and seaweed extract etc. for their potential to replace AGP (Thacker, 2013).

Marketed product survey: Table 8 reported various marketed product thoroughly sold globally as replacement of AGP. Many products from extensive survey were found to full fill the need of AGP in some extent.

Table 8:Market product as a source of NGP and their role on poultry gut health
Image for - Review on Natural Growth Promoters Available for Improving Gut Health of Poultry: An Alternative to Antibiotic Growth Promoters

However, there is still need to set some standards for the replacement of antibiotic compounds in poultry, in terms of product type, identification of suppliers, poultry response criteria, regulatory status and veterinary definition.

CONCLUSION

The potentials of NGPs to AGPs are only of practical significance when they improve animal performance by maintaining gut health and immune functions in given time slot levels. Such thoroughly tested microbiota modulating and immunomodulatory compounds have potential to be used as feed stuff of feed additives for poultry productions. Although market is flooded with numerous products, some of them shown their potential, but at the same time there are many more objectionable products, where efficacy is still questionable. Therefore, there is an urgent need of further studies to develop larger datasets for product based mechanisms of action of each compound in a scientific way. The paper presented list of various NGPs are by no means of exhaustive and there are also many other products design and screened using these requirements day to day claiming to be of value added NGPs in gut health.

REFERENCES

1:  Abbas, R.J., 2010. Effect of using fenugreek, parsley and sweet basil seeds as feed additives on the performance of broiler chickens. Int. J. Poult. Sci., 9: 278-282.
CrossRef  |  Direct Link  |  

2:  Abbas, R.Z., D.D. Colwell and J. Gilleard, 2012. Botanicals: An alternative approach for the control of avian coccidiosis. World's Poult. Sci. J., 68: 203-215.
CrossRef  |  Direct Link  |  

3:  Abbas, R.Z., S.H. Munawar, Z. Manzoor, Z. Iqbal and M.N. Khan et al., 2011. Anticoccidial effects of acetic acid on performance and pathogenic parameters in broiler chickens challenged with Eimeria tenella. Pesquisa Veterinaria Brasileira, 31: 99-103.
CrossRef  |  Direct Link  |  

4:  Abd-El-Motaal, A.M., A.M.H. Ahmed, A.S.A. Bahakaim and M.M. Fathi, 2008. Productive performance and immunocompetence of commercial laying hens given diets supplemented with eucalyptus. Int. J. Poult. Sci., 7: 445-449.
CrossRef  |  Direct Link  |  

5:  Abdelqader, A., A.R. Al-Fataftah and G. Das, 2013. Effects of dietary Bacillus subtilis and inulin supplementation on performance, eggshell quality, intestinal morphology and microflora composition of laying hens in the late phase of production. Anim. Feed Sci. Technol., 179: 103-111.
CrossRef  |  Direct Link  |  

6:  Abdel-Rahman, H.A., S.I. Fathallah, M.A. Helal, A.A. Nafeaa and I.S. Zahran, 2014. Effect of turmeric (Curcuma longa), fenugreek (Trigonella foenum-graecum L.) And/or bioflavonoid supplementation to the broiler chicks diet and drinking water on the growth performance and intestinal morphometeric parameters. Global Vet., 12: 627-635.
Direct Link  |  

7:  Adeola, O. and A.J. Cowieson, 2011. Board-invited review: Opportunities and challenges in using exogenous enzymes to improve nonruminant animal production. J. Anim. Sci., 89: 3189-3218.
CrossRef  |  Direct Link  |  

8:  Adil, S. and S.N. Magray, 2012. Impact and manipulation of gut microflora in poultry: A review. J. Anim. Vet. Adv., 11: 873-877.
Direct Link  |  

9:  Agyemang, K., L. Han, E. Liu, Y. Zhang, T. Wang and X. Gao, 2013. Recent advances in Astragalus membranaceus anti-diabetic research: Pharmacological effects of its phytochemical constituents. Evid.-Based Comp. Alternat. Med., Vol. 2013.
CrossRef  |  Direct Link  |  

10:  Ahmad, I., 2006. Effect of probiotics on broilers performance. Int. J. Poult. Sci., 5: 593-597.
CrossRef  |  Direct Link  |  

11:  Al-Fataftah, A.R. and A. Abdelqader, 2013. Effect of Salix babylonica, Populus nigra and Eucalyptus camaldulensis extracts in drinking water on performance and heat tolerance of broiler chickens during heat stress. Am. Eurasian J. Agric. Environ. Sci., 13: 1309-1313.
Direct Link  |  

12:  Allen, P.C. and R.H. Fetterer, 2002. Recent advances in biology and immunobiology of Eimeria species and in diagnosis and control of infection with these coccidian parasites of poultry. Clin. Microbiol. Rev., 15: 58-65.
CrossRef  |  PubMed  |  Direct Link  |  

13:  Al-Mufarrej, S.I., 2014. Immune-responsiveness and performance of broiler chickens fed black cumin (Nigella sativa L.) powder. J. Saudi Soc. Agric. Sci., 13: 75-80.
CrossRef  |  Direct Link  |  

14:  Amirdahri, S., H. Janmohammadi, A. Taghizadeh and A. Rafat, 2012. Effect of dietary Aspergillus meal prebiotic on growth performance, carcass characteristics, nutrient digestibility and serum lipid profile in broiler chick low-protein diets. Turk. J. Vet. Anim. Sci., 36: 602-610.
Direct Link  |  

15:  Annett, C.B., J.R. Viste, M. Chirino-Trejo, H.L. Classen, D.M. Middleton and E. Simko, 2002. Necrotic enteritis: Effect of barley, wheat and corn diets on proliferation of Clostridium perfringens type A. Avian Pathol., 31: 598-601.
CrossRef  |  Direct Link  |  

16:  Anosa, G.N. and O.J. Okoro, 2011. Anticoccidial activity of the methanolic extract of Musa paradisiaca root in chickens. Trop. Anim. Health Prod., 43: 245-248.
CrossRef  |  Direct Link  |  

17:  Antongiovanni, M., A. Buccioni, F. Petacchi, S. Leeson, S. Minieri, A. Martini and R. Cecchi, 2007. Butyric acid glycerides in the diet of broiler chickens: Effects on gut histology and carcass composition. Ital. J. Anim. Sci., 6: 19-25.
Direct Link  |  

18:  Arab, H.A., S. Rahbari, A. Rassouli, M.H. Moslemi and F. Khosravirad, 2006. Determination of artemisinin in Artemisia sieberi and anticoccidial effects of the plant extract in broiler chickens. Trop. Anim. Health Prod., 38: 497-503.
CrossRef  |  PubMed  |  Direct Link  |  

19:  Awad, W.A., K. Ghareeb and J. Bohm, 2010. Effect of addition of a probiotic micro-organism to broiler diet on intestinal mucosal architecture and electrophysiological parameters. J. Anim. Physiol. Anim. Nutr., 94: 486-494.
CrossRef  |  Direct Link  |  

20:  Awad, W., K. Ghareeb and J. Bohm, 2008. Intestinal structure and function of broiler chickens on diets supplemented with a Synbiotic containing Enterococcus faecium and Oligosaccharides. Int. J. Mol. Sci., 9: 2205-2216.
CrossRef  |  Direct Link  |  

21:  Aziz Mousavi, S.M.A., A.R. Seidavi, M. Dadashbeiki, A. Kilonzo-Nthenge, S.N. Nahashon, V. Laudadio and V. Tufarelli, 2015. Effect of a synbiotic (Biomin® IMBO) on growth performance traits of broiler chickens. Eur. Poult. Sci., 79: 1-15.
CrossRef  |  Direct Link  |  

22:  Aziz Husdfdggsein, A.A., 2010. The effect of the Capsicum annuum in the diet of broilers on the isolation and shedding rate of Salmonella paratyphoid. Kufa J. Vet. Med. Sci., 1: 28-38.
Direct Link  |  

23:  Baffoni, L., F. Gaggia, D. di Gioia, C. Santini, L. Mogna and B. Biavati, 2012. A bifidobacterium-based synbiotic product to reduce the transmission of C. jejuni along the poultry food chain. Int. J. Food Microbiol., 157: 156-161.
CrossRef  |  Direct Link  |  

24:  Bailey, J.S., L.C. Blankenship and N.A. Cox, 1991. Effect of fructooligosaccharide on Salmonella colonization of the chicken intestine. Poult. Sci., 70: 2433-2438.
CrossRef  |  PubMed  |  Direct Link  |  

25:  Baratta, M.T., H.J.D. Dorman, S.G. Deans, D.M. Biondi and G. Ruberto, 1998. Chemical composition, antimicrobial and antioxidative activity of laurel, sage, rosemary, oregano and coriander essential oils. J. Essent. Oil Res., 10: 618-627.
CrossRef  |  Direct Link  |  

26:  Basri, D.F. and S.H. Fan, 2005. The potential of aqueous and acetone extracts of galls of Quercus infectoria as antibacterial agents. Indian J. Pharmacol., 37: 26-29.
CrossRef  |  Direct Link  |  

27:  Baurhoo, B., P.R. Ferket and X. Zhao, 2009. Effects of diets containing different concentrations of mannanoligosaccharide or antibiotics on growth performance, intestinal development, cecal and litter microbial populations and carcass parameters of broilers. Poult. Sci., 88: 2262-2272.
CrossRef  |  Direct Link  |  

28:  Bazafkan, M.H., A. Hardani, M.R.A. Zadeh, A.A. Zargar, N. Moradi and N. Jalali, 2014. The effects of aqueous extract of celery leaves (Apium gravelens) on the delivery rate, sexual ratio and litter number of the female rats. Jentashapir J. Health Res., Vol. 5.
CrossRef  |  

29:  Bedford, M.R. and A.J. Cowieson, 2012. Exogenous enzymes and their effects on intestinal microbiology. Anim. Feed Sci. Technol., 173: 76-85.
CrossRef  |  Direct Link  |  

30:  Biggs, P., C.M. Parsons and G.C. Fahey, 2007. The effects of several oligosaccharides on growth performance, nutrient digestibilities and cecal microbial populations in young chicks. Poult. Sci., 86: 2327-2336.
CrossRef  |  Direct Link  |  

31:  Blank, R., R. Mosenthin, W.C. Sauer and S. Huang, 1999. Effect of fumaric acid and dietary buffering capacity on ileal and fecal amino acid digestibilities in early-weaned pigs. J. Anim. Sci., 77: 2974-2984.
Direct Link  |  

32:  Bozkurt, M., I. Giannenas, K. Kucukyilmaz, E. Christaki and P. Florou-Paneri, 2013. An update on approaches to controlling coccidia in poultry using botanical extracts. Br. Poult. Sci., 54: 713-727.
CrossRef  |  Direct Link  |  

33:  Brenes, A. and E. Roura, 2010. Essential oils in poultry nutrition: Main effects and modes of action. Anim. Feed Sci. Technol., 158: 1-14.
CrossRef  |  Direct Link  |  

34:  Briozzo, J., L. Nunez, J. Chirife, L. Herszage and M. D'Aquino, 1989. Antimicrobial activity of clove oil dispersed in a concentrated sugar solution. J. Appl. Bacteriol., 66: 69-75.
PubMed  |  Direct Link  |  

35:  Caccioni, D.R.L., M. Guizzardi, D.M. Biondi, A. Renda and G. Ruberto, 1998. Relationship between volatile components of citrus fruit essential oils and antimicrobial action on Penicillium digitatum and Penicillium italicum. Int. J. Food Microbiol., 43: 73-79.
CrossRef  |  Direct Link  |  

36:  Capkovicova, A., Z. Makova, E. Piesova, A. Alves, S. Faix and Z. Faixova, 2014. Evaluation of the effects of Salvia officinalis essential oil on plasma biochemistry, gut mucus and quantity of acidic and neutral mucins in the chicken gut. Acta Vet., 64: 138-148.
CrossRef  |  Direct Link  |  

37:  Casanovas, X., X. Manteca, E. Fernandez and E. Gonalons, 1994. Effects of temperature on in vitro palmitic acid uptake by chicken and rat intestinal tissue. Archives internationales de physiologie, de Biochimie et de Biophysique, 102: 233-235.
CrossRef  |  Direct Link  |  

38:  Cheeke, P.R., S. Piacente and W. Oleszek, 2006. Anti-inflammatory and anti-arthritic effects of Yucca schidigera. J. Inflammation, Vol. 3.
CrossRef  |  Direct Link  |  

39:  Chen, H.L., D.F. Li, B.Y. Chang, L.M. Gong, J.G. Dai and G.F. Yi, 2003. Effects of Chinese herbal polysaccharides on the immunity and growth performance of young broilers. Poult. Sci., 82: 364-370.
PubMed  |  Direct Link  |  

40:  Chen, W.L., J.B. Liang, M.F. Jahromi, N. Abdullah, Y.W. Ho and V. Tufarelli, 2015. Enzyme treatment enhances release of prebiotic oligosaccharides from palm kernel expeller. BioResources, 10: 196-209.
Direct Link  |  

41:  Chowdhury, R., K.M.S. Islam, M.J. Khan, M.R. Karim, M.N. Haque, M. Khatun and G.M. Pesti, 2009. Effect of citric acid, avilamycin and their combination on the performance, tibia ash and immune status of broilers. Poult. Sci., 88: 1616-1622.
CrossRef  |  PubMed  |  Direct Link  |  

42:  Christakia, E., P. Florou-Paneria, I. Giannenasa, M. Papazahariadoub, N.A. Botsogloua and A.B. Spaisa, 2004. Effect of a mixture of herbal extracts on broiler chickens infected with Eimeria tenella. Anim. Res., 53: 137-144.
CrossRef  |  Direct Link  |  

43:  Collins, D.M. and G.R. Gibson, 1999. Probiotics, prebiotics and synbiotics: Approaches for modulating the microbial ecology of the gut. Am. J. Clin. Nutr., 69: 1052S-1057S.
PubMed  |  Direct Link  |  

44:  Cosgrove, M., 1998. Nucleotides. Nutrition, 14: 748-751.
CrossRef  |  Direct Link  |  

45:  Courtin, C.M., K. Swennen, W.F. Broekaert, Q. Swennen and J. Buyse et al., 2008. Effects of dietary inclusion of xylooligo-saccharides, arabinoxylooligosaccha-rides and soluble arabinoxylan on the microbial composition of caecal contents of chickens. J. Sci. Food Agric., 88: 2517-2522.
CrossRef  |  Direct Link  |  

46:  Cox, S.D., C.M. Mann, J.L. Markham, H.C. Bell, J.E. Gustafson, J.R. Warmington and S.G. Wyllie, 2000. The mode of antimicrobial action of the essential oil of Melaleuca alternifolia (tea tree oil). J. Applied Microbiol., 88: 170-175.
CrossRef  |  PubMed  |  Direct Link  |  

47:  Cummings, J.H., J.M. Antoine, F. Azpiroz, R. Bourdet-Sicard and P. Brandtzaeg et al., 2004. PASSCLAIM-gut health and immunity. Eur. J. Nutr., 43: ii118-ii173.
CrossRef  |  Direct Link  |  

48:  Curbelo, Y.G., M.G. Lopez, R. Bocourt, Z. Rodriguez and L. Savon, 2012. Prebiotics in the feeding of monogastric animals. Cuban J. Agric. Sci., 46: 231-236.
Direct Link  |  

49:  Czerucka, D. and P. Rampal, 2002. Experimental effects of Saccharomyces boulardii on diarrheal pathogens. Microbes. Infect., 4: 733-739.
CrossRef  |  PubMed  |  Direct Link  |  

50:  Czerucka, D., T. Piche and P. Rampal, 2007. Review article: Yeast as probiotics-Saccharomyces boulardii. Alimentary Pharmacol. Ther., 26: 767-778.
CrossRef  |  Direct Link  |  

51:  Darabighane, B., A. Zarei, A.Z. Shahneh and A. Mahdavi, 2011. Effects of different levels of Aloe vera gel as an alternative to antibiotic on performance and ileum morphology in broilers. Ital. J. Anim. Sci., 10: 189-194.
Direct Link  |  

52:  Davis, G.S. and K.E. Anderson, 2002. The effects of feeding the direct-fed microbial, primalac, on growth parameters and egg production in single comb white leghorn hens. Poult. Sci., 81: 755-759.
CrossRef  |  PubMed  |  Direct Link  |  

53:  Deans, S.G. and G. Ritchie, 1987. Antibacterial properties of plant essential oils. Int. J. Food Microbiol., 5: 165-180.
CrossRef  |  Direct Link  |  

54:  Debnath, B.C., K.B.D. Choudhary, K. Ravikanth, A. Thakur and S. Maini, 2014. Comparative efficacy of natural growth promoter (AV/AGP/10) with antibiotic growth promoter on overall growth performance and intestinal morphometry in broiler birds. Int. J. Pharm. Sci. Health Care, 2: 155-168.
Direct Link  |  

55:  Delaquis, P.J., K. Stanich, B. Girard and G. Mazza, 2002. Antimicrobial activity of individual and mixed fractions of dill, cilantro, coriander and eucalyptus essential oils. Int. J. Food Microbiol., 74: 101-109.
CrossRef  |  PubMed  |  Direct Link  |  

56:  Deng, W.L., 1978. Outline of current clinical and pharmacological research on Andrographis paniculata in China. Newslett. Chin. Herbal Med., 10: 27-31.

57:  De Pablos, L.M., M.F.B. dos Santos, E. Montero, A. Garcia-Granados, A. Parra and A. Osuna, 2010. Anticoccidial activity of maslinic acid against infection with Eimeria tenella in chickens. Parasitol. Res., 107: 601-604.
CrossRef  |  Direct Link  |  

58:  Deplancke, B. and H.R. Gaskins, 2001. Microbial modulation of innate defense: Goblet cells and the intestinal mucus layer. Am. J. Clin. Nutr., 73: 1131S-1141S.
PubMed  |  Direct Link  |  

59:  Dhama, K., S.K. Latheef, M. Saminathan, H.A. Samad and K. Karthik et al., 2015. Multiple beneficial applications and modes of action of herbs in poultry health and production: A review. Int. J. Pharmacol., 11: 152-176.
CrossRef  |  Direct Link  |  

60:  Dibner, J.J. and P. Buttin, 2002. Use of organic acids as a model to study the impact of gut microflora on nutrition and metabolism. J. Applied Poult. Res., 11: 453-463.
CrossRef  |  Direct Link  |  

61:  Dieumou, F.E., A. Teguia, J.R. Kuiate, J.D. Tamokou, N.B. Fonge and M.C. Dongmo, 2009. Effects of ginger (Zingiber officinale) and garlic (Allium sativum) essential oils on growth performance and gut microbial population of broiler chickens. Livest. Res. Rural Dev., 21: 25-34.
Direct Link  |  

62:  Di Pasqua, R., G. Mamone, P. Ferranti, D. Ercolini and G. Mauriello, 2010. Changes in the proteome of Salmonella enterica serovar Thompson as stress adaptation to sublethal concentrations of thymol. Proteomics, 10: 1040-1049.
CrossRef  |  Direct Link  |  

63:  Dorman, H.J.D. and S.G. Deans, 2000. Antimicrobial agents from plants: Antibacterial activity of plant volatile oils. J. Appl. Microbiol., 88: 308-316.
CrossRef  |  Direct Link  |  

64:  Dorman, H.J.D., S.G. Deans, R.C. Nob and P. Surai, 1995. Evaluation in vitro of plant essential oils as natural antioxidants. J. Essent. Oil Res., 7: 645-651.
CrossRef  |  Direct Link  |  

65:  Dudonne, S., P. Poupard, P. Coutiere, M. Woillez, T. Richard, J.M. Merillon and X. Vitrac, 2011. Phenolic composition and antioxidant properties of poplar bud (Populus nigra) extract: Individual antioxidant contribution of phenolics and transcriptional effect on skin aging. J. Agric. Food Chem., 59: 4527-4536.
CrossRef  |  Direct Link  |  

66:  Maroufyan E., A. Kasim, M. Ebrahimi, T.C. Loh and M. Hair-Bejo et al., 2012. Omega-3 polyunsaturated fatty acids enrichment alters performance and immune response in infectious bursal disease challenged broilers. Lipids Health Dis., Vol. 11.
CrossRef  |  Direct Link  |  

67:  Eevuri, T.R. and R. Putturu, 2013. Use of certain herbal preparations in broiler feeds-A review. Vet. World, 6: 172-179.
CrossRef  |  Direct Link  |  

68:  El-Ghany, W.A.A., 2010. Comparative evaluation on the Effect of Coccidiostate and Synbiotic Preparations on Prevention of Clostridium perfringens in broiler chickens. Global Vet., 5: 324-333.
Direct Link  |  

69:  Elizondo, A.M., E.C. Mercado, B.C. Rabinovitz and M.E. Fernandez-Miyakawa, 2010. Effect of tannins on the in vitro growth of Clostridium perfringens. Vet. Microbiol., 145: 308-314.
CrossRef  |  Direct Link  |  

70:  Abd El-Latif, A.S., N.S. Saleh, T.S. Allam and E.W. Ghazy, 2013. The effects of rosemary (Rosemarinus afficinalis) and garlic (Allium sativum) essential oils on performance, hematological, biochemical and immunological parameters of broiler chickens. Br. J. Poult. Sci., 2: 16-24.
Direct Link  |  

71:  El-Sissi, A.F. and S.H. Mohamed, 2011. Impact of symbiotic on the immune response of broiler chickens against NDV and IBV vaccines. Global J. Biotechnol. Biochem., 6: 186-191.
Direct Link  |  

72:  El-Soud, N.H.A., N.A. El-Lithy, G. El-Saeed, M.S. Wahby, M.Y. Khalil, F. Morsy and N. Shaffie, 2014. Renoprotective effects of Caraway (Carum carvi L.) essential oil in streptozotocin induced diabetic rats. J. Applied Pharm. Sci., 4: 27-33.
Direct Link  |  

73:  Engberg, R.M., K. Grevsen, E. Ivarsen, X. Frette and L.P. Christensen et al., 2012. The effect of Artemisia annua on broiler performance, on intestinal microbiota and on the course of a Clostridium perfringens infection applying a necrotic enteritis disease model. Avian Pathol., 41: 369-376.
CrossRef  |  Direct Link  |  

74:  Fajardo, P., L. Pastrana, J. Mendez, I. Rodriguez, C. Fucinos and N.P. Guerra, 2012. Effects of feeding of two potentially probiotic preparations from lactic acid bacteria on the performance and faecal microflora of broiler chickens. Sci. World J.
CrossRef  |  

75:  Farsam, H., M. Amanlou, M.R. Radpour, A.N. Salehinia and A. Shafiee, 2003. Composition of the essential oils of wild and cultivated Satureja khuzistanica Jamzad from Iran. Flavour Fragran. J., 19: 308-310.
CrossRef  |  Direct Link  |  

76:  Fujiwara, Y., C. Masutani, F. Hanaoka and S. Iwai, 1996. Detection, purification and characterization of a protein that binds the (6-4) photoproduct-containing DNA in HeLa cells. Nucleic Acids Symp. Ser., 37: 277-278.
Direct Link  |  

77:  Gajewska, J., J. Riedel, A. Bucka, J. Zabik and M. Michalczuk, 2012. Influence of prebiotics and butyric acid on the composition of intestinal microflora of broiler chickens. Ann. Warsaw Univ. Life Sci.-SGGW Anim. Sci, 51: 47-53.

78:  Ganguly, S., 2013. Promising pharmaceutical effect of various biological and inorganic agents as feed supplements for livestock and poultry with discussion on research proven facts and establishment of concept: A specialized review. Int. J. Res. Pharm. Life Sci., 1: 115-120.

79:  Gaskins, H.R., R.I. Mackie, T. May and K.A. Garleb, 1996. Dietary fructo-oligosaccharide modulates large intestinal inflammatory responses to Clostridium difficile in antibiotic-compromised mice. Microb. Ecol. Health Dis., 9: 157-166.
CrossRef  |  Direct Link  |  

80:  Giannenas, I., E. Tsalie, E. Chronis, S. Mavridis, D. Tontis and I. Kyriazakis, 2011. Consumption of Agaricus bisporus mushroom affects the performance, intestinal microbiota composition and morphology, and antioxidant status of turkey poults. Animal Feed Sci. Technol., 165: 218-229.
CrossRef  |  Direct Link  |  

81:  Gibson, G.R. and M.B. Roberfroid, 1995. Dietary modulation of the human colonic microbiota: Introducing the concept of prebiotics. J. Nutr., 125: 1401-1412.
CrossRef  |  PubMed  |  Direct Link  |  

82:  Grashorn, M.A., 2010. Use of phytobiotics in broiler nutrition-an alternative to infeed antibiotics? J. Anim. Feed Sci., 19: 338-347.
Direct Link  |  

83:  Griggs, J.P. and J.P. Jacob, 2005. Alternatives to antibiotics for organic poultry production. J. Applied Poult. Res., 14: 750-756.
CrossRef  |  Direct Link  |  

84:  Guo, F.C., B.A. Williams, R.P. Kwakkel, H.S. Li and X.P. Li et al., 2004. Effects of mushroom and herb polysaccharides, as alternatives for an antibiotic, on the cecal microbial ecosystem in broiler chickens. Poult. Sci., 83: 175-182.
CrossRef  |  Direct Link  |  

85:  Gupta, S., M.A. Choudhry and J.N.S. Yadava, 1990. Antidiarrioeal activity diterpenes of Andrographis paniculata (Kalmegh) agent Escherichia coli enterotoxin in vivo models. Int. J. Crude Drug Res., 28: 273-283.

86:  Haghighi, H.R., J. Gong, C.L. Gyles, M.A. Hayes and H. Zhou et al., 2006. Probiotics stimulate production of natural antibodies in chickens. Clin. Vaccine Immunol., 13: 975-980.
CrossRef  |  Direct Link  |  

87:  Hajati, H. and M. Rezaei, 2010. The application of prebiotics in poultry production. Int. J. Poult. Sci., 9: 298-304.
CrossRef  |  Direct Link  |  

88:  Hara, Y., 1997. Influence of tea catechins on the digestive tract. J. Cell. Biochem., 27: 52-58.
CrossRef  |  PubMed  |  Direct Link  |  

89:  Hashemi, S.R. and H. Davoodi, 2010. Phytogenics as new class of feed additive in poultry industry. J. Anim. Vet. Adv., 9: 2295-2304.
CrossRef  |  Direct Link  |  

90:  Hashemi, S.R., I. Zulkifli, H. Davoodi, M.H. Bejo and T.C. Loh, 2014. Intestinal histomorphology changes and serum biochemistry responses of broiler chickens fed herbal plant (Euphorbia hirta) and mix of acidifier. Iran. J. Applied Anim. Sci., 4: 95-103.
Direct Link  |  

91:  Hashemipour, H., H. Kermanshahi, A. Golian and T. Veldkamp, 2013. Effect of thymol and carvacrol feed supplementation on performance, antioxidant enzyme activities, fatty acid composition, digestive enzyme activities and immune response in broiler chickens. Poult. Sci., 92: 2059-2069.
Direct Link  |  

92:  He, J., J. Yin, L. Wang, B. Yu and D. Chen, 2010. Functional characterisation of a recombinant xylanase from Pichia pastoris and effect of the enzyme on nutrient digestibility in weaned pigs. Br. J. Nutr., 103: 1507-1513.
CrossRef  |  Direct Link  |  

93:  He, X., H. Zhang, X. Yang, S. Zhang, Q. Dai, W. Xiao and G. Ren, 2007. Modulation of immune function by conjugated linoleic acid in chickens. Food Agric. Immunol., 18: 169-178.
CrossRef  |  Direct Link  |  

94:  Hernandez, F., V. Garcia, J. Madrid, J. Orengo, P. Catala and M.D. Megias, 2006. Effect of formic acid on performance, digestibility, intestinal histomorphology and plasma metabolite levels of broiler chickens. Br. Poult. Sci., 47: 50-56.
CrossRef  |  PubMed  |  Direct Link  |  

95:  Higgins, J.P., S.E. Higgins, A.D. Wolfenden, S.N. Henderson and A. Torres-Rodriguez et al., 2010. Effect of lactic acid bacteria probiotic culture treatment timing on Salmonella enteritidis in neonatal broilers. Poult. Sci., 89: 243-247.
CrossRef  |  Direct Link  |  

96:  Ho, T.Y., H.Y. Lo, C.C. Li, J.C. Chen and C.Y. Hsiang, 2013. In vitro and in vivo bioluminescent imaging to evaluate anti-Escherichia coli activity of Galla Chinensis. BioMedicine, 3: 160-166.
CrossRef  |  Direct Link  |  

97:  Huang, L.Z., H. Zhao, B. Huang, C. Zheng and W. Peng et al., 2011. Acanthopanax senticosus: Review of botany, chemistry and pharmacology. Pharmazie, 66: 83-97.
PubMed  |  Direct Link  |  

98:  Humphrey, B.D. and K.C. Klasing, 2003. Modulation of nutrient metabolism and homeostasis by the immune system. Proceedings of the European Symposium on Poultry Nutrition, August 10-14, 2003, Lillehammer, Norway -

99:  Huyghebaert, G., R. Ducatelle and F. van Immerseel, 2011. An update on alternatives to antimicrobial growth promoters for broilers. Vet. J., 187: 182-188.
CrossRef  |  Direct Link  |  

100:  Iji, P.A., A.A. Saki and D.R. Tivey, 2001. Intestinal structure and function of broiler chickens on diets supplemented with a mannan oligosaccharide. J. Sci. Food Agric., 81: 1186-1192.
CrossRef  |  Direct Link  |  

101:  Ishihara, N., D.C. Chu, S. Akachi and L.R. Juneja, 2001. Improvement of intestinal microflora balance and prevention of digestive and respiratory organ diseases in calves by green tea extracts. Livest. Prod. Sci., 68: 217-229.
CrossRef  |  Direct Link  |  

102:  Izat, A.L., N.M. Tidwell, R.A. Thomas, M.A. Reiber, M.H. Adams, M. Colberg and P.W. Waldroup, 1990. Effects of buffered propionic acid in diets on the performance of broiler chicken and on microflora of the intestine and carcass. Poult. Sci., 69: 818-826.
PubMed  |  Direct Link  |  

103:  Jamroz, D., J. Orda, C. Kamel, A. Wiliczkiewicz, T. Wertelecki and J. Skorupinska, 2003. The influence of phytogenic extracts on performance, nutrient digestibility, carcass characteristics and gut microbial status in broiler chickens. J. Anim. Feed Sci., 12: 583-596.
Direct Link  |  

104:  Jang, J.P., 2011. Effect of different levels of coriander oil on performance and blood parameters of broiler chicks. Ann. Biol. Res., 2: 578-583.
Direct Link  |  

105:  Jang, S.I., M.H. Jun, H.S. Lillehoj, R.A. Dalloul, I.K. Kong, S. Kim and W. Min, 2007. Anticoccidial effect of green tea-based diets against Eimeria maxima. Vet. Parasitol., 144: 172-175.
CrossRef  |  Direct Link  |  

106:  Jin, L.Z., Y.W. Ho, N. Abdullah and S. Jalaludin, 1997. Probiotics in poultry: Modes of action. World's Poult. Sci. J., 53: 351-368.
CrossRef  |  Direct Link  |  

107:  Kamel, C., 2001. Natural Plant Extracts: Classical Remedies Bring Modern Animal Production Solutions. In: Sow Feed Manufacturing in the Mediterranean Region: Improving safety: From Feed to Food, Brufau, J. (Ed.). CIHEAM., Reus, Spain, pp: 31-38

108:  Kapoor, I.P.S., B. Singh, G. Singh, V. Isidorov and L. Szczepaniak, 2008. Chemistry, antifungal and antioxidant activities of cardamom (Amomum subulatum) essential oil and oleoresins. Int. J. Essential Oil Ther., 2: 29-40.
Direct Link  |  

109:  Khaksefidi, A. and S. Rahimi, 2005. Effect of probiotic inclusion in the diet of broiler chickens on performance, feed efficiency and carcass quality. Asian Aust. J. Anim. Sci., 18: 1153-1156.
Direct Link  |  

110:  Khan, R.U., S. Naz, Z. Nikousefat, V. Tufarelli and V. Laudadio, 2012. Thymus vulgaris: Alternative to antibiotics in poultry feed. World's Poult. Sci. J., 68: 401-408.
CrossRef  |  Direct Link  |  

111:  Khan, R.U., S. Naz, Z. Nikousefat, V. Tufarelli, M. Javdani, M.S. Qureshi and V. Laudadio, 2012. Potential applications of ginger (Zingiber officinale) in poultry diets. World's Poult. Sci. J., 68: 245-252.
CrossRef  |  Direct Link  |  

112:  Khan, S.H., 2014. The use of green tea (Camellia sinensis) as a phytogenic substance in poultry diets. Onderstepoort J. Vet. Res., 81: 1-8.
Direct Link  |  

113:  Killeen, G.F., C.R. Connolly, G.A. Walsh, C.F. Duffy, D.R. Headon and R.F. Power, 1998. The effects of dietary supplementation with Yucca schidigera extract or fractions thereof on nitrogen metabolism and gastrointestinal fermentation processes in the rat. J. Sci. Food Agric., 76: 91-99.
CrossRef  |  Direct Link  |  

114:  Kim, D.K., H.S. Lillehoj, S.H. Lee, S.I. Jang, E.P. Lillehoj and D. Bravo, 2013. Dietary Curcuma longa enhances resistance against Eimeria maxima and Eimeria tenella infections in chickens. Poult. Sci., 92: 2635-2643.
Direct Link  |  

115:  Kim, G.B., Y.M. Seo, C.H. Kim and I.K. Paik, 2011. Effect of dietary prebiotic supplementation on the performance, intestinal microflora and immune response of broilers. Poult Sci., 90: 75-82.
CrossRef  |  Direct Link  |  

116:  Kizerwetter-Swida, M. and M. Binek, 2009. Protective effect of potentially probiotic Lactobacillus strain on infection with pathogenic bacteria in chickens. Pol. J. Vet. Sci., 12: 15-20.
PubMed  |  

117:  Knap, I., A.B. Kehlet, M. Bennedsen, G.F. Mathis and C.L. Hofacre et al., 2011. Bacillus subtilis (DSM17299) significantly reduces Salmonella in broilers. Poult. Sci., 90: 1690-1694.
CrossRef  |  PubMed  |  

118:  Kong, X.F., F.G. Yin, Q.H. He, H.J. Liu and T.J. Li et al., 2009. Acanthopanax senticosus extract as a dietary additive enhances the apparent ileal digestibility of amino acids in weaned piglets. Livest. Sci., 123: 261-267.
CrossRef  |  

119:  Kudoh, K., J. Shimizu, M. Wada, T. Takita, Y. Kanke and S. Innami, 1998. Effect of indigestible saccharides on B lymphocyte response of intestinal mucosa and cecal fermentation in rats. J. Nutr. Sci. Vitaminol., 44: 103-112.
CrossRef  |  

120:  Kumar, S., R. Malhotra and D. Kumar, 2010. Euphorbia hirta: Its chemistry, traditional and medicinal uses and pharmacological activities. Pharmacogn. Rev., 4: 58-61.
CrossRef  |  PubMed  |  Direct Link  |  

121:  Kumari, C.S., S. Govindasamy and E. Sukumar, 2006. Lipid lowering activity of Eclipta prostrate in experimental hyperlipidemia. J. Ethnopharmacol., 105: 332-335.
CrossRef  |  PubMed  |  

122:  Kutlu, H.R., I. Unsal and M. Gorgulu, 2001. Effects of providing dietary wood (oak) charcoal to broiler chicks and laying hens. Anim. Feed Sci. Technol., 90: 213-226.
CrossRef  |  Direct Link  |  

123:  Lan, P.T.N., M. Sakamoto and Y. Benno, 2004. Effects of two probiotic Lactobacillus strains on jejunal and cecal microbiota of broiler chicken under acute heat stress condition as revealed by molecular analysis of 16S rRNA genes. Microbiol. Immunol., 48: 917-929.
CrossRef  |  Direct Link  |  

124:  Landy, N., G. Ghalamkari and M. Toghyani, 2011. Performance, carcass characteristics and immunity in broiler chickens fed dietary neem (Azadirachta indica) as alternative for an antibiotic growth promoter. Livestock Sci., 142: 305-309.
Direct Link  |  

125:  La Ragione, R.M. and M.J. Woodward, 2003. Competitive exclusion by Bacillus subtilis spores of Salmonella enterica serotype Enteritidis and Clostridium perfringens in young chickens. Vet. Microbiol., 94: 245-256.
CrossRef  |  PubMed  |  Direct Link  |  

126:  Laudadio, V., A. Dambrosio, G. Normanno, R.U. Khan, S. Naz, E. Rowghani and V. Tufarelli, 2012. Effect of reducing dietary protein level on performance responses and some microbiological aspects of broiler chickens under summer environmental conditions. Avian Biol. Res., 5: 88-92.
CrossRef  |  

127:  Leandro, N.S.M., A.S.C. Oliveira, E. Gonzales, M.B. Cafe, L.H. Stringhini and M.A. Andrade, 2010. [Probiotic in diet or inoculated in fertilized eggs. 1. Performance of broiler chicks challenged with Salmonella enteritidis]. Rev. Bras. Zootecn., 39: 1509-1516.
CrossRef  |  Direct Link  |  

128:  Lee, H.S. and Y.J. Ahn, 1998. Growth-inhibiting effects of Cinnamomum cassia bark-derived materials on human intestinal bacteria. J. Agric. Food Chem., 46: 8-12.
CrossRef  |  PubMed  |  Direct Link  |  

129:  Lee, K.W., H. Everts and A.C. Beynen, 2004. Essential oils in broiler nutrition. Int. J. Poult. Sci., 3: 738-752.
CrossRef  |  Direct Link  |  

130:  Lee, S.H., H.S. Lillehoj, S.I. Jang, D.K. Kim, C. Ionescu and D. Bravo, 2010. Effect of dietary curcuma, capsicum and lentinus on enhancing local immunity against Eimeria acervulina infection. J. Poult. Sci., 47: 89-95.
CrossRef  |  

131:  Lee, T.T., C.L. Chen, C.C. Wang and B. Yu, 2012. Growth performance and antioxidant capacity of broilers supplemented with Echinacea purpurea L. in the diet. J. Applied Poult. Res., 21: 484-491.
Direct Link  |  

132:  Li, X.Q., L. Qiang, Liu and C.L. Xu, 2008. Effects of supplementation of fructooligosaccharide and/or Bacillus subtilis to diets on performance and on intestinal microflora in broilers. Archiv. fur Tierzucht, 51: 64-70.
Direct Link  |  

133:  Lievin, V., I. Peiffer, S. Hudault, F. Rochat, D. Brassart, J.R. Neeser and A.I. Servin, 2000. Bifidobacterium strains from resident infant human gastrointestinal microflora exert antimicrobial activity. Gut, 47: 646-652.
CrossRef  |  

134:  Marinova, E.M., A. Toneva and N. Yanishlieva, 2009. Comparison of the antioxidative properties of caffeic and chlorogenic acids. Food Chem., 114: 1498-1502.
CrossRef  |  

135:  Martin-Venegas, R., M.T. Brufau, A.M. Guerrero-Zamora, Y. Mercier, P.A. Geraert and R. Ferrer, 2013. The methionine precursor DL-2-hydroxy-(4-methylthio) butanoic acid protects intestinal epithelial barrier function. Food Chem., 141: 1702-1709.
CrossRef  |  Direct Link  |  

136:  McDevitt, R.M., J.D. Brooker, T. Acamovic and N.H.C. Sparks, 2006. Necrotic enteritis; a continuing challenge for the poultry industry. World's Poult. Sci. J., 62: 221-247.
CrossRef  |  Direct Link  |  

137:  Michels, M.G., L.C. Bertolini, A.F. Esteves, P. Moreira and S.C. Franca, 2011. Anticoccidial effects of coumestans from Eclipta alba for sustainable control of Eimeria tenella parasitosis in poultry production. Vet. Parasitol., 177: 55-60.
CrossRef  |  PubMed  |  Direct Link  |  

138:  Mirzaei-Aghsaghali, A., 2012. Importance of medical herbs in animal feeding: A review. Ann. Biol. Res., 3: 918-923.
Direct Link  |  

139:  Lievin-Le Moal, V. and A.L. Servin, 2006. The front line of enteric host defense against unwelcome intrusion of harmful microorganisms: Mucins, antimicrobial peptides and microbiota. Clin. Microbiol. Rev., 19: 315-337.
Direct Link  |  

140:  Mondal, S.K., B. Ray, S. Thakur and P.K. Ghosal, 2001. Isolation, purification and some structural features of the mucilaginous exudate from Musa paradisiacal. Fitoterapia, 72: 263-271.
CrossRef  |  Direct Link  |  

141:  Mookiah, S., C.C. Sieo, K. Ramasamy, N. Abdullah and Y.W. Ho, 2014. Effects of dietary prebiotics, probiotic and synbiotics on performance, caecal bacterial populations and caecal fermentation concentrations of broiler chickens. J. Sci. Food Agric., 94: 341-348.
CrossRef  |  PubMed  |  Direct Link  |  

142:  Mountzouris, K.C., P. Tsirtsikos, E. Kalamara, S. Nitsch, G. Schatzmayr and K. Fegeros, 2007. Evaluation of the efficacy of a probiotic containing Lactobacillus, Bifidobacterium, Enterococcus and Pediococcus strains in promoting broiler performance and modulating cecal microflora composition and metabolic activities. Poult. Sci., 86: 309-317.
Direct Link  |  

143:  Muchtaridi, A. Subarnas, A. Apriyantono and R. Mustarichie, 2010. Identification of compounds in the essential oil of nutmeg seeds (Myristica fragrans houtt.) that inhibit locomotor activity in mice. Int. J. Mol. Sci., 11: 4771-4781.
CrossRef  |  

144:  Mueller, K., M.B. Nicole, H. Kluge, R. Bauerfeind and J. Froehlich et al., 2012. Effects of broccoli extract and various essential oils on intestinal and faecal microflora and on xenobiotic enzymes and the antioxidant system of piglets. Open J. Anim. Sci., 2: 78-98.
CrossRef  |  Direct Link  |  

145:  Nabizadeh, A., 2012. The effect of inulin on broiler chicken intestinal microflora, gut morphology and performance. J. Anim. Feed Sci., 21: 725-734.
CrossRef  |  Direct Link  |  

146:  Nasiri, F., T.B. Ghiassi, A.R. Bassiri, S.E. Hoseini and M. Aminafshar, 2013. Comparative study on the main chemical composition of button mushroom's (Agaricus bisporus) cap and stipe. J. Food Biosci. Technol., 3: 41-48.
Direct Link  |  

147:  Nurmi, E. and M. Rantala, 1973. New aspects of Salmonella infection in broiler production. Nature, 241: 210-211.
CrossRef  |  PubMed  |  Direct Link  |  

148:  Nweze, N.E. and I.S. Obiwulu, 2009. Anticoccidial effects of Ageratum conyzoides. J. Ethnopharmacol., 122: 6-9.
CrossRef  |  Direct Link  |  

149:  Ocak, N., G. Erener, F. Burak Ak, M. Sungu, A. Altop and A. Ozmen, 2008. Performance of broilers fed diets supplemented with dry peppermint (Mentha piperita L.) or thyme (Thymus vulgaris L.) leaves as growth promoter source. Czech J. Anim. Sci., 53: 169-175.
CrossRef  |  Direct Link  |  

150:  Ogbe, A.O., S.E. Atawodi, P.A. Abdu, A. Sannusi and A.E. Itodo, 2009. Changes in weight gain, faecal oocyst count and packed cell volume of Eimeria tenella-infected broilers treated with a wild mushroom (Ganoderma lucidum) aqueous extract. J. S. Afr. Vet. Assoc., 80: 97-102.
PubMed  |  Direct Link  |  

151:  Ontario, G., 2012. Prebiotics and β-glucan in modulation of growth performance, nutrient utilization and alkaline phosphatase kinetics in the weanling pig. M.Sc. Thesis, University of Guelph, Canada.

152:  Owen, O.J., M.B. Nodu, U.A. Dike and H.M. Ideozu, 2012. The effects of dietary kaolin (clay) as feed additive on the growth performance of broiler chickens. Greener J. Agric. Sci., 2: 233-236.
Direct Link  |  

153:  Padihari, V.P., S.P. Tiwari, T. Sahu, M.K. Gendley and S.K. Naik, 2014. Effects of mannan oligosaccharide and Saccharomyces cerevisiae on gut morphology of broiler chickens. J. World's Poult. Res., 4: 56-59.
Direct Link  |  

154:  Panda, K., S.V.R. Rao and M.V.L.N. Raju, 2006. Natural growth promoters have potential in poultry feeding systems. Feed Tech., 10: 23-25.
Direct Link  |  

155:  Partanen, K.H. and Z. Mroz, 1999. Organic acids for performance enhancement in pig diets. Nutr. Res. Rev., 12: 117-145.
CrossRef  |  Direct Link  |  

156:  Pascual, M., M. Hugas, J.I. Badiola, J.M. Monfort and M. Garrgia, 1999. Lactobacillus salivarius CTC2197 prevents Salmonella enteritidis colonization in chickens. Applied Environ. Microbiol., 65: 4981-4986.
PubMed  |  Direct Link  |  

157:  Paul, I., D.P. Isore, S.N. Joardar, B. Roy, R. Aich and S. Ganguly, 2013. Effect of dietary yeast cell wall preparation on innate immune response in broiler chickens. Indian J. Anim. Sci., 83: 307-309.
Direct Link  |  

158:  Pelicano, E.R.L., P.A. Souza, H.B.A. Souza, D.F. Figueiredo, M.M. Boiago, S.R. Carvalho and V.F. Bordon, 2005. Intestinal mucosa development in broiler chickens fed natural growth promoters. Rev. Bras. Cienc. Avic., 7: 221-229.
CrossRef  |  Direct Link  |  

159:  Pereira, V., C. Dias, M.C. Vasconcelos, E. Rosa and M.J. Saavedra, 2014. Antibacterial activity and synergistic effects between Eucalyptus globulus leaf residues (essential oils and extracts) and antibiotics against several isolates of respiratory tract infections (Pseudomonas aeruginosa). Ind. Crops Prod., 52: 1-7.
CrossRef  |  

160:  Peric, L., N. Milosevic, D. Zikic, S. Bjedov and D. Cvetkovic et al., 2010. Effects of probiotic and phytogenic products on performance, gut morphology and cecal microflora of broiler chickens. Arch. Tierzucht, 53: 350-359.
Direct Link  |  

161:  Pettey, L.A., S.D. Carter, B.W. Senne and J.A. Shriver, 2002. Effect of β-mannanase addition to corn-soybean meal diets on growth performance, carcass traits and nutrient digestibility of weanling and growing-finishing pigs. J. Anim. Sci., 80: 1012-1019.
PubMed  |  

162:  Pourhossein, Z., A.A.A. Qotbi, A. Seidavi, V. Laudadio, G. Centoducati and V. Tufarelli, 2015. Effect of different levels of dietary sweet orange (Citrus sinensis) peel extract on humoral immune system responses in broiler chickens. Anim. Sci. J., 86: 105-110.
CrossRef  |  Direct Link  |  

163:  Rabsch, W., B.M. Hargis, R.M. Tsolis, R.A. Kingsley, K.H. Hinz, H. Tschape and A.J. Baumler, 2000. Competitive exclusion of Salmonella enteritidis by Salmonella gallinarum in poultry. Emerg. Infect. Dis., 6: 443-448.
CrossRef  |  

164:  Ranaa, V.S. and M.A. Blazquezb, 2003. Chemical composition of the volatile oil of Ageratum conyzoides aerial parts. Int. J. Aromather., 13: 203-206.
CrossRef  |  Direct Link  |  

165:  Remmal, A., S. Achahbar, L. Bouddine, N. Chami and F. Chami, 2011. In vitro destruction of Eimeria oocysts by essential oils. Vet. Parasitol., 182: 121-126.
CrossRef  |  Direct Link  |  

166:  Rodriguez-Fragoso, L., A. Sandoval-Ocampo, M. Corbala-Nava, C.A. Arjona-Canul and D.L. Gomez-Galicia et al., 2012. Evaluation regarding the efficacy and safety of a probiotic mixture in healthy volunteers with evacuation disorders. Food Nutr. Sci., 3: 117-122.
CrossRef  |  Direct Link  |  

167:  Salem, A.M.Z., M.Z.M. Salem, M. Gonzalez-Ronquillo, L.M. Camacho and M. Cipriano, 2011. Major chemical constituents of Leucaena leucocephala and Salix babylonica leaf extracts. J. Trop. Agric., 49: 95-98.
Direct Link  |  

168:  Salgado-Transito, L., J.C. Del Rio-Garcia, J.L. Arjona-Roman, E. Moreno-Martinez and A. Mendez-Albores, 2011. Effect of citric acid supplemented diets on aflatoxin degradation, growth performance and serum parameters in broiler chickens. Archivos de Medicina Veterinaria, 43: 215-222.
Direct Link  |  

169:  Sanders, M.E., 1999. Probiotics. Food Technolol., 53: 67-75.

170:  Saraswathi, J., K. Venkatesh, N. Baburao, M.H. Hilal and A. Roja Rani, 2011. Phytopharmacological importance of Pelargonium species. J. Med. Plant Res., 5: 2587-2598.
Direct Link  |  

171:  Schade, R., E.G. Calzado, R. Sarmiento, P.A. Chacana, J. Porankiewicz-Asplund and H.R. Terzolo, 2005. Chicken egg yolk antibodies (IgY-technology): A review of progress in production and use in research and human and veterinary medicine. Altern. Lab. Anim., 33: 129-154.

172:  Schiavone, A., K. Guo, S. Tassone, L. Gasco, E. Hernandez, R. Denti and I. Zoccarato, 2008. Effects of a natural extract of chestnut wood on digestibility, performance traits and nitrogen balance of broiler chicks. Poult. Sci., 87: 521-527.
CrossRef  |  PubMed  |  Direct Link  |  

173:  Sethiya, N.K., M.M.M. Raja and S.H. Mishra, 2013. Antioxidant markers based TLC-DPPH differentiation on four commercialized botanical sources of Shankhpushpi (A Medhya Rasayana): A preliminary assessment. J. Adv. Pharm. Technol. Res., 4: 25-30.
Direct Link  |  

174:  Sethiya, N.K., S.G. Thakore and S.H. Mishra, 2009. Comparative evaluation of commercial sources of indigenous medicine shankhpushpi for anti-stress potential a preliminary study. Pharmacol. Online, 2: 460-467.

175:  Shahwar, M.K., A.H. El-Ghorab, F.M. Anjum, M.S. Butt, S. Hussain and M. Nadeem, 2012. Characterization of coriander (Coriandrum sativum L.) seeds and leaves: Volatile and non volatile extracts. Int. J. Food Properties, 15: 736-747.
CrossRef  |  Direct Link  |  

176:  Shojaii, A. and M.A. Fard, 2012. Review of pharmacological properties and chemical constituents of Pimpinella anisum. ISRN Pharmaceutics, Vol. 2012.
CrossRef  |  

177:  Sienkiewicz, M., M. Lysakowska, M. Pastuszka, W. Bienias and E. Kowalczyk, 2013. The potential of use basil and rosemary essential oils as effective antibacterial agents. Molecules, 18: 9334-9351.
CrossRef  |  Direct Link  |  

178:  Simon, O., A. Jadamus and W. Vahjen, 2001. Probiotic feed additives-effectiveness and expected modes of action. J. Anim. Feed. Sci., 10: 51-67.
Direct Link  |  

179:  Sims, M.D., K.A. Dawson, K.E. Newman, P. Spring and D.M. Hoogell, 2004. Effects of dietary mannan oligosaccharide, bacitracin methylene disalicylate, or both on the live performance and intestinal microbiology of Turkeys. Poult. Sci., 83: 1148-1154.
CrossRef  |  PubMed  |  Direct Link  |  

180:  Singh, S., B. Sankar, S. Rajesh, K. Sahoo, E. Subudhi and S. Nayak, 2011. Chemical composition of turmeric oil (Curcuma longa L. cv. Roma) and its antimicrobial activity against eye infecting pathogens. J. Essential Oil Res., 23: 11-18.
CrossRef  |  Direct Link  |  

181:  Singh, S.K., P.S. Niranjan, U.B. Singh, S. Koley and D.N. Verma, 2009. Effects of dietary supplementation of probiotics on broiler chicken. Anim. Nutr. Feed Technol., 9: 85-90.

182:  Sinovec, Z. and R. Markovic, 2005. Using Prebiotics in poultry nutrition. Biotech. Anim. Husbandry, 21: 235-239.
Direct Link  |  

183:  Siragusa, G.R., G.J. Haas, P.D. Matthews, R.J. Smith, R.J. Buhr, N.M. Dale and M.G. Wise, 2008. Antimicrobial activity of lupulone against Clostridium perfringens in the chicken intestinal tract jejunum and caecum. J. Antimicrob. Chemother., 61: 853-858.
Direct Link  |  

184:  Sommer, F. and F. Backhed, 2013. The gut microbiota-masters of host development and physiology. Nat. Rev. Microbiol., 11: 227-238.
CrossRef  |  Direct Link  |  

185:  Srinivasan, K., 2007. Black pepper and its pungent principle-piperine: A review of diverse physiological effects. Crit. Rev. Food Sci. Nutr., 47: 735-748.
CrossRef  |  PubMed  |  Direct Link  |  

186:  Stein, H.H. and D.Y. Kil, 2006. Reduced use of antibiotic growth promoters in diets fed to weanling pigs: Dietary tools, part 2. Anim. Biotechnol., 17: 217-231.
CrossRef  |  Direct Link  |  

187:  Stern, N.J., E.A. Svetoch, B.V. Eruslanov, V.V. Perelygin and E.V. Mitsevich et al., 2006. Isolation of a Lactobacillus salivarius strain and purification of its bacteriocin, which is inhibitory to Campylobacter jejuni in the chicken gastrointestinal system. Antimicrob. Agents Chemother., 50: 3111-3116.
CrossRef  |  Direct Link  |  

188:  Sugiharto, S., 2014. Role of nutraceuticals in gut health and growth performance of poultry. J. Saudi Soc. Agric. Sci.
CrossRef  |  

189:  Szczurek, W., 2008. Dried whey products and their use in diets for broilers. Nutritional and physiological aspects. Wiadomosci Zootechniczne, 4: 41-52.

190:  Tako, E., R.P. Glahn, M. Knez and J.C. Stangoulis, 2014. The effect of wheat prebiotics on the gut bacterial population and iron status of iron deficient broiler chickens. Nutr. J., Vol. 13.
Direct Link  |  

191:  Thacker, P.A., 2013. Alternatives to antibiotics as growth promoters for use in swine production: A review. J. Anim. Sci. Biotechnol., Vol. 4.
CrossRef  |  

192:  Thanissery, R., J.L. McReynolds, D.E. Conner, K.S. Macklin, P.A. Curtis and Y.O. Fasina, 2010. Evaluation of the efficacy of yeast extract in reducing intestinal Clostridium perfringens levels in broiler chickens. Poult. Sci., 89: 2380-2388.
Direct Link  |  

193:  Tomer, K., N.K. Sethiya, A. Shete and V. Singh, 2010. Isolation and characterization of total volatile components from leaves of Citrus limon linn. J. Adv. Pharm. Technol. Res., 1: 49-55.
Direct Link  |  

194:  Van Parys, A., F. Boyen, J. Dewulf, F. Haesebrouck and F. Pasmans, 2010. The use of tannins to control Salmonella typhimurium infections in pigs. Zoonoses Public Health, 57: 423-428.
CrossRef  |  Direct Link  |  

195:  Vidanarachchi, J.K., L.L. Mikkelsen, C.C. Constantinoiu, M. Choct and P.A. Iji, 2013. Natural plant extracts and prebiotic compounds as alternatives to antibiotics in broiler chicken diets in a necrotic enteritis challenge model. Anim. Prod. Sci., 53: 1247-1259.
CrossRef  |  Direct Link  |  

196:  Vidanarachchi, J.K., L.L. Mikkelsen, I.M. Sims, P.A. Iji and M. Choct, 2006. Selected plant extracts modulate the gut microflora in broilers. Aust. Poult. Sci. Symp., 18: 145-148.
Direct Link  |  

197:  Vogt, H., S. Matthes and S. Harnisch, 1982. Effect of organic acids in rations on the performances of broilers. Arch. Geflugelkd., 46: 223-227.

198:  Vondruskova, H., R. Slamova, M. Trckova, Z. Zraly and I. Pavlik, 2010. Alternatives to antibiotic growth promoters in prevention of diarrhoea in weaned piglets: A review. Vet. Med., 55: 199-224.
Direct Link  |  

199:  Waldenstedt, L., J. Inborr, I. Hansson and K. Elwinger, 2003. Effects of astaxanthin-rich algal meal (Haematococcus pluvalis) on growth performance, caecal campylobacter and clostridial counts and tissue astaxanthin concentration of broiler chickens. Anim. Feed Sci. Technol., 108: 119-132.
CrossRef  |  Direct Link  |  

200:  Wallace, R.J., W. Oleszek, C. Franz, I. Hahn, K.H.C. Baser, A. Mathe and K. Teichmann, 2010. Dietary plant bioactives for poultry health and productivity. Br. Poult. Sci., 51: 461-487.
CrossRef  |  Direct Link  |  

201:  Wang, F., D. Yang, S. Ren, H. Zhang and R. Li, 1999. Chemical composition of essential oil from leaves of Litsea cubeba and its antifungal activities. Zhong Yao Cai, 22: 400-402.
PubMed  |  Direct Link  |  

202:  Wang, M.L., X. Suo, J.H. Gu, W.W. Zhang, Q. Fang and X. Wang, 2008. Influence of grape seed proanthocyanidin extract in broiler chickens: Effect on chicken coccidiosis and antioxidant status. Poult. Sci., 87: 2273-2280.
CrossRef  |  Direct Link  |  

203:  Wang, R., D. Li and S. Bourne, 1998. Can 2000 years of herbal medicine history help us solve problems in the year 2000. Proceedings of Alltech's 14th Annual Symposium, (AAS`98), Kentucky, USA., pp: 273-291

204:  Williams, J., S. Mallet, M. Leconte, M. Lessire and I. Gabriel, 2008. The effects of fructo-oligosaccharides or whole wheat on the performance and digestive tract of broiler chickens. Br. Poult. Sci., 49: 329-339.
CrossRef  |  Direct Link  |  

205:  Willis, W.L., O.S. Isikhuemhen and S.A. Ibrahim, 2007. Performance assessment of broiler chickens given mushroom extract alone or in combination with probiotics. Poult. Sci., 86: 1856-1860.
CrossRef  |  Direct Link  |  

206:  Woo, K.C., B.Y. Jung, M.K. Lee and I.K. Paik, 2006. Effects of supplementary Safmannan (beta glucan and MOS) and World-Las (multiple probiotics) on the performance, nutrient availability, small intestinal microflora and immune response in broiler chicks. Korean J. Poult. Sci., 33: 151-158.

207:  Xie, Q., J. Li and X. Zhou, 2008. Anticaries effect of compounds extracted from Galla chinensis in a multispecies biofilm model. Oral Microbiol. Immunol., 23: 459-465.
CrossRef  |  Direct Link  |  

208:  Yan, L. and I.H. Kim, 2012. Effect of eugenol and cinnamaldehyde on the growth performance, nutrient digestibility, blood characteristics, fecal microbial shedding and fecal noxious gas content in growing pigs. Asian-Aust. J. Anim. Sci., 25: 1178-1183.
CrossRef  |  Direct Link  |  

209:  Yang, Y., P.A. Iji and M. Choct, 2009. Dietary modulation of gut microflora in broiler chickens: A review of the role of six kinds of alternatives to in-feed antibiotics. World's Poult. Sci. J., 65: 97-114.
CrossRef  |  Direct Link  |  

210:  Yang, Y., P.A. Iji, A. Kocher, L.L. Mikkelsen and M. Choct, 2008. Effects of dietary mannanoligosaccharide on growth performance, nutrient digestibility and gut development of broilers given different cereal-based diets. J. Anim. Physiol. Anim. Nutr., 92: 650-659.
CrossRef  |  PubMed  |  Direct Link  |  

211:  Yegani, M. and D.R. Korver, 2008. Factors affecting intestinal health in poultry. Poult. Sci., 87: 2052-2063.
CrossRef  |  Direct Link  |  

212:  Yılmaz, S., S. Ergun and N. Soytas, 2013. Dietary supplementation of cumin (Cuminum cyminum) preventing streptococcal disease during first-feeding of Mozambique tilapia (Oreochromis mossambicus). J. BioSci. Biotech., 2: 117-124.
Direct Link  |  

213:  Yuan, S.L., X.S. Piao, D.F. Li, S.W. Kim, H.S. Lee and P.F. Guo, 2006. Effects of dietary Astragalus polysaccharide on growth performance and immune function in weaned pigs. Anim. Sci., 62: 501-507.
CrossRef  |  Direct Link  |  

214:  Zhou, P., Y.Q. Tan, L. Zhang, Y.M. Zhou, F. Gao and G.H. Zhou, 2014. Effects of dietary supplementation with the combination of zeolite and attapulgite on growth performance, nutrient digestibility, secretion of digestive enzymes and intestinal health in broiler chickens. Asian-Aust. J. Anim. Sci., 27: 1311-1318.
CrossRef  |  Direct Link  |  

215:  Bischoff, S.C., 2011. Gut health: A new objective in medicine? BMC Medicine, Vol. 9.
CrossRef  |  Direct Link  |  

216:  Pasteiner, S., 2006. New natural concept for poultry gut health. Int. Poult. Prod., 14: 17-17.
Direct Link  |  

217:  Lindberg, J.E., 2014. Fiber effects in nutrition and gut health in pigs. J. Anim. Sci. Biotechnol., Vol. 5, No. 1.
CrossRef  |  Direct Link  |  

218:  Edens, F.W., 2003. An alternative for antibiotic use in poultry: Probiotics. Brazil. J. Poult. Sci., 5: 75-97.
CrossRef  |  Direct Link  |  

©  2022 Science Alert. All Rights Reserved