Abstract: This study was conducted to represent the role of Flammulina velutipes stem in laying hen ration for improving laying performances and health status of layer chicken. Flammulina velutipes is one of the most popular edible mushroom in Asian countries and known as winter mushroom. Inclusion of Flammulina velutipes stem (FVS) in layer diets is the most effective supplement in order to improve laying performance, egg quality, intestinal morphology, cecal microflora and excreta composition. It has been reported that FVS in laying hen could improve laying performance and egg quality including Feed Conversion Ratio (FCR), egg mass, egg size, egg yolk cholesterol and yolk fatty acid. Flammulina velutipes stem can change small intestinal morphology that might help to increase nutrient absorption in chicken. Flammulina velutipes stem also reported on controlling pathogenic bacteria as well as increasing beneficial bacteria in cecum to keep sound gut health in layer chickens. Flammulina velutipes stem had indirect effect on suppression of ammonia gas in feces by reducing moisture content in feces. Therefore supplementation of winter mushroom stem could be useful strategy to improve laying performance, egg quality and sound gut health in layer.
INTRODUCTION
Inclusion of dietary winter mushroom (Flammulina velutipes) stem in layer diet can be used for improving laying hen performance and health status including Feed Conversion Ratio (FCR), egg mass, egg quality, cecal microflora, excreta Dry Matter (DM) and excreta ammonia gas emission. Flammulina velutipes is the thin white mushroom commonly used in east Asian countries such as China, Japan, Vietnam and Korea. These mushrooms are also known by the name golden needle mushroom or lily mushroom or winter mushroom1. Mushrooms are recognized as having considerable health benefits and desirable functions. It also has long been appreciated for their flavor and texture, medicinal and tonic attributes. However, the more recent concept is that mushroom represents an important source of biologically active compounds of medicinal value. Mushrooms are now known to be rich in high quality protein, vitamin, minerals and a high proportion of unsaturated fatty acids1. The use of probiotics, products made from living micro-organisms including bacteria, fungi and yeast have been considered a strong substitute to antibiotics because probiotics do not lead to antibiotic-resistant bacteria in the gastrointestinal tract2. Anti-inflammatory, anti-tumor and immune-modulating drugs as well as dietary supplements were produced form the mushrooms3. Mushroom wastes are widely left from mushroom production industries and have been supposed to possess prebiotic, anti-microbial, anti-fungal and anti-oxidant properties4. Flammulina velutipes, one of the most popular edible mushrooms has attracted considerable attention of biochemistry and pharmacology due to its biological activities5. Flammulina velutipes is an excellent source of essential amino acids and vitamins, this fungi also exhibits good anti-oxidant, anti-inflammatory, immunomodulatory, anti-tumor and cholesterol-lowering activities6,7. In addition, F. velutipes also contains various kinds of bioactive substance such as α-glucan, hetero polysaccharides, mannofucogalactan and monoterpenes, which have anti-carcinogenic and immunomodulating effect8,9. Moreover, compounds with medicinal properties have been isolated from the fruiting body and mycelial culture of this mushroom, including proteins with antiviral and immunomodulatory activity10, polysaccharides with immunomodulatory activity3, lectin with anti-tumor activity11, sesquiterpenoids with antimicrobial activity12,13 and sterol14. In the meantime functional polysaccharide is discovered from F. velutipes mushroom that may play effective role in poultry production. However, potential use of F. velutipes in animal study is still limited.
Since many years researchers are looking for natural unconventional feed resources to improve the animal and poultry production performance. With the removal of antibiotic growth promoters from poultry diets in different areas of the world, it is of interest to investigate potential substitute to maintain optimum performance, intestinal health and microbial populations, particularly to control the growth of harmful bacteria. Due to recent ban of using antibiotic as growth promoters in poultry diet, mushroom wastes could be a proper substitute for antibiotic in poultry ration. Flammulina velutipes stem is an agricultural byproduct having nutritional and medicinal values and its availability is abundant but up to now its utilization is limited for animal production. Very few studies have been carried out yet to evaluate the feasibility of Flammulina velutipes stem on laying hens. Considering the above facts, this study was focused on the use of Flammulina velutipes stem as a feed ingredient as well as a substitute of antibiotics to improve productivity and health status in laying hens.
PROXIMATE ANALYSIS OF F. velutipes STEM
The chemical analysis of F. velutipes stem showed that Dry Matter (DM) 84-89.6%, Crude Protein (CP) 8.9-11.8%, carbohydrate 43.33-69.40%, Total Detergent Fiber (TDF) 1.9-7.40%, crude fat (EE) 1.79-2.91%, ash (total mineral) 4.91-7.40%, calcium (Ca) 2.21% and phosphorus (P) 1.68% by previously published value15-18 . The low fat but high in protein as well as fiber is the unique character of F. velutipes mushroom. Flammulina velutipes is also exhibit excellent sources of amino acids like methionine, valine, isoleucine, leucine, lysine, phenylalanine and threonine those are very important and sensitive nutrient components in poultry diet19.
EFFECT OF F. velutipes STEM SUPPLEMENTATION IN LAYING PERFORMANCE
Few studies have been conducted in previous years to investigate the effect of dietary F. velutipes stem supplementation in layer chickens. Lee et al.20 reported that fermented F. velutipes mycelium showed positive effect on laying performance parameters including; egg mass, egg size and FCR in laying hens. It was thought that F. velutipes stem contain higher level of CP that lead to increase egg albumin and might have effect on shell gland for continuous egg shell formation. Lee et al.18 stated that adding F. velutipes mycelium at 5% in layer diet did not affect feed intake but slightly improved growth performance and FCR. Hen mortality was significantly low that was directly associated with immunity gained from supplemented F. velutipes stem as the polysaccharides in F. velutipes have immune modulatory activity1,3,21,22.
EFFECT OF F. velutipes STEM SUPPLEMENTATION ON EGG QUALITY
The egg quality parameters including; egg size, shell thickness, egg yolk cholesterol directly and indirectly influence to egg consumers. Dietary supplementation of 4% F. velutipes mycelium could improve egg shell weight, shell thickness albumin height and haugh unit20,23. In contrast Na et al.17 reported that dietary supplementation of F. velutipes media had no effect on egg shell weight and thickness. Sun et al.24 reported that edible mushrooms have hypo-cholesterolemic effect on health and suggested to use it as oral medicine. Yeh et al.25 investigated the effect of the active components of both F. velutipes powder and F. velutipes extract on the lipid metabolism of male hamsters on a high fat diet. The study revealed that both F. velutipes extract and powder at dose of 3% are capable of reducing the level of Total Cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL) and LDL/HDL (high density lipoprotein cholesterol) in the serum and liver of the hamsters significantly. At present considerable interest has arisen in the use of natural antioxidants derived from unconventional resources for improving egg quality by increasing its anti-oxidative potential. Butylated hydroxyanisole and butylated hydroxytoluene are examples of potent synthetic anti-oxidants, however, some of them are found to be toxic and carcinogenic to human body, thus efforts are now focusing on discovering natural anti-oxidant products26. It was assumed that F. velutipes stem have antioxidant activity helped to reduce oxidation in egg yolk resulted lower thiobarbituric acid value (TBA). The polysaccharide (Flammulina velutipes polysaccharide, FVP I-A) has strong anti-oxidant and immunomodulatory value21. Phenolic compounds especially phenolic acid is the major naturally occurring anti-oxidant components found in medicinal mushrooms like F. velutipes27,28. However, there is no evidence as to whether dietary supplementation of dried winter mushrooms can improve oxidative stability of chicken tissues. Flammulina velutipes mushroom is also considered as a good source of selenium compounds and probably the selenium of F. velutipes improved the oxidative stability of egg yolk29. Diet contains rich in total omega-3 fatty acid (n-3), total omega-6 fatty acid (n-6) as well as Poly Unsaturated Fatty Acid (PUFA) is useful for human and animal health. A diet rich in n-3 PUFA is thought to be therapeutic beneficial for people with either cardiovascular disease or rheumatoid arthritis and very useful for their preventative role in a wide range of conditions30,31. Flammulina velutipes naturally contain smaller quantity of Saturated Fatty Acid (SFA) and Mono Unsaturated Fatty Acid (MUFA) than PUFA32. Higher abdominal fat in laying hen can reduce total egg production and cause some metabolic disorders like fatty liver diseases and winter mushroom could be an alternative way to overcome this problem.
EFFECT OF F. velutipes STEM ON SMALL INTESTINAL MORPHOLOGY
Chickens intestine morphological characteristics are very important for optimum nutrient utilization as well as for keeping good health. Higher intestinal absorptive and good gut health is associated with the higher villus height and lower crypt depth4. The structural improvement of villus height and villus height-crypt depth ratio may be correlated with high content of crude fiber in FV mushroom. Many studies have been suggested that supplementation of mushroom increased the duodenal, jejunal and ileal villus height of the birds4,33.
EFFECT OF F. velutipes STEM ON GUT HEALTH
Gut system affect the way nutrients are partitioned and utilized for organ development, tissue growth and immune system maturation. Cecal microflora populations are indicative of gut health in animals and poultry. Diet has direct and indirect role to keep healthy gut in poultry. Laying hens fed supplemented with F. velutipes (3-5%) could reduced the pathogenic bacteria like Salmonella spp., E. coli and Clostridium spp., as well as increased change in concentration of beneficial bacteria of Lactobacillus spp., and Bifidobacterium spp.,18,20,34. Flammulina velutipes have immunomodulatory effect via induction of cytokines 22,35. Guo et al.36 stated that mushroom and herb extract diets reduced Bacteroides spp., Enterococci and E. coli numbers, but increased numbers of Bifidobacteria and Lactobacilli. Another study by Willis et al.37 stated that Bifidobacteria proliferation is enhanced with the mushroom extract. The polysaccharides from F. velutipes mycorrhizae (PFVM) increased the body weight to mice and the weight ratio of the thymus and spleen as a result, the T-cell sub population of thymocytes and splenocytes were modulated by the administration of PFVM25. In addition, water-soluble polysaccharide from F. velutipes (FVPl-A) resulted in increased Nitric Oxide (NO) and TNF-a production. The IL-1b and IL-6 was also increased and lymphocyte proliferation was promoted21.
EFFECT OF F. velutipes STEM ON EXCRETA COMPOSITION AND GAS PRODUCTION
Higher excreta Dry Matter (DM) content can prevent the problems caused by wet litter in layer farms as well as increased the absorption of nutrients and reduce the ammonia gas production in faeces. The higher level of ammonia concentration in poultry houses is undesirable because ammonia is toxic and has been implicated for high chick’s mortality and poor chicken growth38. In addition high concentrations of ammonia (NH3) from manure impair productivity, including growth rate39 and egg production40 as well as damaging the respiratory tract41. Lee et al.20 who observed that the addition of 4-5% fermented FV stem in the laying hens feed can decrease NH3 gas emission in feces. Flammulina velutipes stem can be used in laying hen ration to improve the DM content of excreta which might help to reduce gas production as well as solve the problems caused by unexpected gas production in laying hen excreta.
CONCLUSION
Winter mushroom has been reported as immune enhancers, anti-bacterial, anti-viral, anti-oxidant, anti-inflammatory and cholesterol lowering effect in many species including chicken. Flammulina velutipes stem has both nutritional and medicinal value for therapeutic use and pharmaceutical uses. The fruiting body and stem of F. velutipes mushroom have significant impact on improving chicken health and production performance. In fact, this review study observed that F. velutipes stem could improve the laying hen production performance like hen-day egg production and Feed Conversion Ratio (FCR). Egg quality parameters including egg weight, egg shell thickness, haugh unit, egg yolk cholesterol, yolk fatty acid were positively affected with F. velutipes stem supplementation in layer. Addition of winter mushroom stem improved gut health by altering small intestinal morphology and suppressing pathogenic bacteria in laying hen intestine. Flammulina velutipes stem also improved excreta DM and excreta NH3 gas emission in layer. It could be suggested that F. velutipes stem may be used as a novel feed supplement in layer diet for effective utilization of natural resources as well as substitute to antibiotics. Finally, the above information represented in this review may help the basis knowledge about potential uses of F. velutipes stem in poultry ration for the future study.
SIGNIFICANCE STATEMENT
This study discover the F. velutipes mushroom stem as a potential feed supplementation as well as substitute of antibiotics that can be beneficial for laying performance, egg quality, intestinal morphology, immunity and gut health in layer chicken. This study will help the researcher to uncover the critical areas of immunity, gut health as well as egg quality that many researchers were not able to explore. Thus a new theory on improving the laying hen performance with F. velutipes mushroom stem may be arrived at.