|
|
|
|
Research Article
|
|
Effect of Dietary Antibiotic, Probiotic and Prebiotic as Growth Promoters, on Growth Performance, CarcassCharacteristics and Hematological Indices of Broiler Chickens |
|
A. Ashayerizadeh,
N. Dabiri,
O. Ashayerizadeh,
K.H. Mirzadeh,
H. Roshanfekr
and
M. Mamooee
|
|
|
ABSTRACT
|
This experiment was conducted for comparison the effects
of antibiotic (flavomycin), probiotic (primalac), prebiotic (Biolex-MB)
and mixture of probiotic and prebiotic (primalac plus Biolex-MB) as dietary
growth promoter on growth performance, carcasscharacteristics and hematological
indices of broiler chickens. Three hundred day old Ross 308 broilers were
equally distributed into 30 floor pens and reared for 42 day. A basal
diet was formulated covering the recommendations of NRC (1994) for starter
(0-21 days) and grower (22-42 days) periods and considered as control
diet. Four tested diets were formulated by supplemented the basal control
diet with antibiotic (flavomycin), probiotic (primalac), prebiotic (Biolex-MB)
and mixture of primalac plus Biolex-MB, respectively. Six replicates were
used for each treatment. The results of present study showed that all
growth promoters used was improved growth indices of Ross 308 broilers.
The highest significant (p<0.05) values of carcass and thigh were recorded
for broilers fed diet supplemented with flavomycin. The highest (p>0.05)
value of breast was recorded for broilers fed the diet supplemented with
primalac, meanwhile the lower value were showed for birds fed either diet
or diet supplemented with Biolex-MB. The percent of carcass and cuts followed
the same trend. Hematological parameter including cholesterol was recorded
the highest (p>0.05) values groups fed the diets either control or
supplemented with flavomycin, meanwhile the lower value was showed for
bird fed diet supplemented primalac plus Biolex-MB. Triglycerides and
very low density lipoprotein cholesterol (VLDL) were recorded the highest
concentration for bird fed both control and diet supplemented with flavomycin
groups while least concentration was found for bird fed diet supplemented
with primalac. The results of present study revealed that probiotic and
prebiotic as growth promoters can use as alternatives non-antibiotic feed
additives to their free harmful side effects on the consumers and to improve
broiler chickens growth indices.
|
|
|
|
How
to cite this article:
A. Ashayerizadeh, N. Dabiri, O. Ashayerizadeh, K.H. Mirzadeh, H. Roshanfekr and M. Mamooee, 2009. Effect of Dietary Antibiotic, Probiotic and Prebiotic as Growth Promoters, on Growth Performance, CarcassCharacteristics and Hematological Indices of Broiler Chickens. Pakistan Journal of Biological Sciences, 12: 52-57.
DOI: 10.3923/pjbs.2009.52.57
URL: https://scialert.net/abstract/?doi=pjbs.2009.52.57
|
|
|
|
|
INTRODUCTION
For many years, antimicrobial compounds have been used in the poultry breeding
industry for improvement in health status and performance of birds by reduction
or correction of the population of the bacteria present in the gestero-intestinal
(GI) tract (Fairchild et al., 2001). Growth stimulating
antibiotics, by the spread of antibiotic-resistant bacteria, are a threat to
human health (Wray and Davies, 2000; Turnidge,
2004). Following a severe limitation or a general inhibition of using antibiotics
as growth stimulating and therapeutic agents in the poultry industry, probiotics
and prebiotics have been suggested as appropriate alternatives (Piray
et al., 2007). Probiotics are live microbial complements that leave
useful effects on the host through an improvement in the intestines microbial
equilibrium (Fuller, 1989). Different microbial species
such as bacteria (Bacilli, Bifidobacteria, Enterococcus,
Lactobacillus, Streptococcus), yeasts (Saccharomyces cerevisiae),
fungi (Aspergillus oryzae and Aspergillus niger) and indefinite
mixed cultures have been used as probiotics (Simon et
al., 2001). Primalac is a kind of commercial probiotic that contains
at least 1x108 CFU g-1 Lactobacillus casei, Lactobacillus
acidophilus, Bifidobacterium thermophilum and Enterococcus faesium
(Chichlowski et al., 2007a, b).
Prebiotics such as indigestible carbohydrates that leave a desired effect on
the host, by selective growth stimulation or activation of one or more bacteria
in a large part of the gastero-intestinal tract (Gibson and
Roberfroid, 1995). Oligosaccharides such as fructooligosaccharides, galactooligosaccharides
and mannan oligosaccharides are among the most important prebiotics that have
been studied as alternatives to antibiotics (Spring, 1999).
Biolex-MB is a commercial prebiotic of the mannan-oligosaccharides family, which
is obtained by extraction from the outer cell wall of the yeast Saccharomyces
cereviciae. Several studies have shown that use of probiotics and prebiotics
additive in the ration, improves the performance of broiler chickens (Kermanshahi
and Rostami, 2006; Piray et al., 2007).
The combination of probiotics and prebiotics is called, synbiotic (Gibson
and Roberfroid, 1995; Collins and Gibson, 1999; Schrezenmeir
and De-Vrese, 2001). This combination can improve the viability of probiotic
microorganisms, since they are able to use prebiotics as a substra for fermentation
(Bengmark and Bengmark, 2001).
The search for new additives effective on the animal growth and free
from harmful side effects on the consumers health is still continuing.
The purpose of this study was comparing the effects of the antibiotic
flavomycin and alternatives non-antibiotic feed additives containing primalac
and Biolex-MB as alternatives for the growth stimulating antibiotics on
the performance and hematological measures parameters of broiler chickens.
MATERIALS AND METHODS
In this study, 300 broiler chickens of the commercial Ross 308 strain were
used in a randomized completely design with 5 treatments (6 replicates in each
treatment 10 birds/replicates) and reared on the floor pens for 42 days. Before
beginning this study, the dry matter, crude protein, ether extract, crude fiber
and ash contents of main feed ingredients were determined (AOAC,
1984) in the laboratory to make sure of the presence of sufficient amounts
of protein and crude fiber content of the ration.
A basal diet was formulated and considered as control according to recommendation
of NRC (1994) for starter (0-21 days) and grower (22-42
days) diets. Four tested diets were formulated by supplemented the basal control
diet with antibiotic flavomycin (650 g t-1), probiotic (Primalac,
900 g t-1), prebiotic (Biolex-MB, 2000 g t-1) and mixture
of Primalac (900 g t-1), + Biolex-MB (2000 g t-1), respectively.
Six replicates were used for each treatment (Table 1).
During the experiment, water and feed were given to the birds ad libitum. Weighing
of the feed and chickens were made on a weekly basis. At 42nd day of the experimental
period, 5 mL of blood was collected from wing vein from 6 birds in each treatment.
Blood samples were centrifuged (at 2, 000xrpm for 10 min) and serum was separated
and then stored at -20 °C until assayed for measuring blood parameters (glucose,
total protein, albumin, cholesterol, triglyceride and high density lipoprotein
cholesterol (HDL)) using appropriate laboratory kits (Friedewald
et al., 1972; Gordon et al., 1977;
Gowenlock et al., 1988). The serum globulin was
calculated by subtracting serum albumin from serum total protein levels. Very
low density lipoprotein cholesterol (VLDL) was calculated from triglycerides
by dividing the factor 5.
Table 1: |
The experiment basal diets composition and calculated
proximate analysis (on dry matter basis) |
 |
Nitrogen free extract (%) mixing Vitamin and mineral
provided per kilogram of diet: vitamin A, 360000 IU; Vitamin D3, 800000
IU; Vitamin E, 7200 IU; Vitamin K3, 800 mg; Vitamin B1, 720 mg; Vitamin
B9, 400 mg; Vitamin H2, 40 mg; Vitamin B2, 2640 mg, Vitamin B3, 4000
mg; Vitamin B5, 12000 mg; Vitamin B6, 1200 mg; Vitamin B12, 6 mg;
Choline, 200000 mg; Manganeze, 40000 mg; Iron, 20000 mg; Zinc, 40000
mg; Coper, 4000 mg; Iodine, 400 mg; Selenium, 80 mg |
The low density lipoprotein
cholesterol (LDL) was calculated by using the formula:
LDL cholesterol = Total cholesterol–HDL
cholesterol–VLDL cholesterol |
The birds were slaughtered for separation of carcasses (Perreault
and Leeson, 1992).
Statistical analysis: All data were analyzed using the one-way anova
procedure of SAS® (SAS, 1998) for analysis
of variance. Significant differences among treatments were identified at 5%
level by Duncans multiple range tests (Duncan, 1955).
RESULTS AND DISCUSSION
Growth performance: The effect of experimental treatments on the
performance of broiler chickens is given in Table 2.
The dietary supplemented with flavimycin, primalac, Biolex-MB and the
primalac-Biolex-MB mixture, were increased the weight of the birds to
130.8, 73.5, 81.3 and 148.8 g, respectively compard to control diet (Table
2).
The weight gain was increased for birds fed primalac and Biolex-MB by
7.4% compared to control diet.
The above mentioned growth stimulating had no effect on the feed consumption
of the birds. As similar trend mentioned for weight gain, in the birds under
treatments of flavomycin, Biolex-MB and the primalac and Biolex-MB mix, the
feed conversion ratio improved significantly when compared to control group
(p<0.05). In general the positive effects of experimental additives tested on
performance is in agreement with the results reported by several researchers.
Fairchild et al. (2001), who showed that flavomycin
as antibiotics has favorable effects on the weight gain of broiler chickens.
Kermanshahi and Rostami (2006), Thitaram
et al. (2005) and Nayebpor et al. (2007),
reported that probiotics and prebiotics can improve the weight of birds. Esteve-garcia
et al. (1997) observed that addition of flavomycin to a wheat-based
ration could improve significantly the chickens feed conversion ratio
in all breeding periods (0-21 and 21-42 days). Moreover, adding probiotic and
synbiotic to the ration has been effective in improving the feed conversion
ratio (Zulkifli et al., 2000; Cavit,
2004). In contrast, Ignacio, (1995) reported that
the use of prebiotics in the ration of broiler chickens reduces the feed conversion
ratio. Yalcinkayal et al. (2008), Gunal
et al. (2006), Willis et al. (2007),
Jamroz et al. (2004) and Denli
et al. (2003) reported that using this additive shed in the broiler
ration had no significant effects on body weight gain and feed conversion ratio
after experimental period of 42 days 42. In agreement with the results of this
study, there are numerous reports showing that the use of such additives has
no effect on the feed consumption (Yalcinkayal et al.,
2008; Willis et al., 2007; Pelicia
et al., 2004). Adverse results were reported by Piray
et al. (2007) and Nayebpor et al. (2007).
Table 2: |
The main effects of treatments on performance of broiler
chickens at 42 days (Mean ± SE) |
 |
a, bMeans in each column with different superscripts
are significantly different (p<0.05) |
Variance among reports of researchers could be related to differences in management
and environmental conditions that be exist in various experiments. Its
suggested that under benefit management and/or environmental conditions, the
effect of such feed additives may be worthless. The results of some studies
shown that growth stimulating antibiotics, increase the growth of broiler chickens
by an increase in the uptake of nutrients (especially fatty acids and glucose),
fixation of nitrogen and reduction in excretion of fat in the feces and microbial
urea (Anderson et al., 1999). The antibiotics
reduce the number of bacteria, toxins and their secondary products in the GI
tract (Gunal et al., 2006). Present findings shown
that consumption of primalac-biolex mixture, like that of antibiotics, had a
positive effect on the body weight gain. The reason may be ascribed to the synergism
of primalac and Biolex-MB. Following the concurrent action of prebiotics
fermentation by lactic acid bacteria in the GI tract and production of some
acids by this group of bacteria, the pH of the GI tract is further reduced (Fuller,
1989). Reduction in pH is effective in controlling the population of pathogenic
bacteria. During the infections due to pathogenic bacteria, lymphocytes crowd
up to kill them and after inflammation, the thickness of the muscular layer
increases (Gunal et al., 2006). It seems that
in our study, due to the synergism between primalac and Biolex-MB, followed
by absorption of nutrients by the GI system, the birds under synbiotic treatment
had a better feed conversion ratio.
Carcass composition: The effect of experimental treatments on
the composition of the bird carcasses (in grams) and the carcass efficiency
(in %) are given in Table 3.
Table 3: |
The effect of feed additives on carcass composition
of broiler chickens |
 |
a,b,cMeans in each row with different superscripts
are significantly different (p<0.05) |
Table 4: |
The effect of feed additives on serum total protein,
albumin, globulin and glucose of broiler chickens |
 |
a, b, cMeans in each column with different
superscripts are significant different (p<0.05) |
Table 5: |
The effect of feed additives on serum lipid concentrations
of broiler chickens |
 |
a,b,cMeans in each column with different
superscripts are significant different (p<0.05) |
The weight and the efficiency of the dressing carcass in birds under
flavomycin treatment was significantly higher as compared with the control
and Biolex-MB treatments (p<0.05). The weight and the efficiency of
the thigh of birds obtaining a ration containing synbiotic showed a higher
mean as compared with the control treatment (p<0.05).
Also, the birds under primalac treatment had the highest percent breast and
weight and birds under Biolex-MB treatment had the least abdominal fat percent
and weight among the experimental treatments. In spite of the highest amount
and percentage of abdominal fat in control group, the carcass, thigh and breast
of this group were lowest than other groups except Biolex-MB fed group. The
positive effect of the antibiotic use on the weight of broiler carcasses the
confirm results of this experiment (Woodward et al.,
1988; Elwinger et al., 1998).
Kabir et al. (2004) have reported that adding
2 g probiotic per each liter of water consumed by broiler chickens, would increase
the efficiency in their thigh and breast as compared with the control treatment
that confirm the positive effect of primalac on breast yield in this study.
In the Ammerman et al. (1989) study, adding 0.375%
oligofructose to the birds ration, on day 47, decreased the percent of
abdominal fat. This result was similar to the effect of Biolex-MB on abdominal
fat in birds in present experiment. The positive effect of prebiotic on carcass
quality were also reported by Piray et al. (2007).
However, present findings on carcasse composition were in contrast to those
of Pelicia et al. (2004), Pelicano
et al. (2003), Willis et al. (2007) and
Kannan et al. (2005). As pointed out before, these
differences between reported results could be related to management and environmental
conditions.
In this study, it seems that the use of flavomycin, primalac and primalac-Biolex-MB
mix, by improving the uptake of nutrients and increase in nitrogen stability
(Nahashon et al., 1996), can improve the carcass
quality. Also, by observing a reduction in the fat level of birds fed by prebiotic,
it is suggested that this product can interfere in the accessibility to fat
for formation of fat tissue in the birds.
Biochemical parameters: As Table 4 shown all
blood parameters not affected by treatments, with exception of cholesterol,
triglycerides and VLDL. All non-antibiotic additives had significantly
lowered (p<0.05) cholesterol level than control and flavomycin treatments.
In the birds under primalac treatment, the serum triglyceride and VLDL
were lower than these under the control and flavomycin treatments (p<0.05)
(Table 5).
In agreement with the result of cholesterol in this experiment, it is reported
that the use of 100 mg kg-1 of the probiotic supplement (Lactobacillus
acidophilus, Bifidobacterium and Aspergillus oryzae) significantly
reduces the serum cholesterol level of the chickens (Panda
et al., 2001). Kannan et al. (2005)
have reported that the use of 0.5 g kg-1 mannan oligosaccharide obtained
from yeast in the ration of broiler chickens, significantly reduced the serum
cholesterol level on day 35 as compared with the control (p<0.05). Synthesis
of bile acids from cholesterol in the liver, is the most important way of cholesterol
excretion (Wilson et al., 1998). The use of probiotics
and prebiotics can, by the activity of lactic acid bacteria, production of enzymes
disintegrating bile salts and de-conjugating them, as well as reduction of the
pH in the intestinal tract, can be effective in reducing the cholesterol connect
ration. Solvability of non-conjugate bile acids is lowered at a low pH and consequently,
they are absorbed less from the intestine and are excreted more in the feces
(Klaver and Van der Meer, 1993). Consequently, the liver,
for re-establishment of the hepatic cycle of bile acids, coverts more cholesterol
concentration into the tissues and therefore their concentrations in the blood
is reduced (Ros, 2000). In the growing birds, VLDL is
the most important triglyceride carrier.
A reduction in the serum triglyceride level can be due to an increase in the
population of lactic acid bacteria in the GI tract. Santose
et al. (1995) have reported that supplementation of Bacillus subtilis
to the ration of broiler chickens, in addition to reducing the carcass fat,
reduces the triglyceride concentration in the serum, the liver and the carcass
and suggest that this bacterium can be effective in reducing the activity of
acetyl coenzyme A carboxilase (the enzyme limiting the synthesis rate of fatty
acids).
CONCLUSION
It is concluded that by using non-antibiotic additives particularly mixing
of both probiotic and prebiotic could obtained the advantages of antibiotic
(performance) without their disadvantages (high cholesterol, triglycerids,
etc).
|
REFERENCES |
Ammerman, E., C. Quarles and P.V. Twining, 1989. Evaluation of fructooligosaccharides on performance and carcass yield of male broilers. Poult. Sci., 68: 167-167.
Anderson, D.B., V.J. McCracken, R.I. Aminov, J.M. Simpson, R.I. Mackie, M.W.A. Verstegen and H.R. Gaskins, 1999. Gut microbiology and growth-promoting antibiotics in Swine. Pig News Inform., 20: 115-122. Direct Link |
AOAC., 1984. Official Methods of Analysis. 14th Edn., The William Byrd Press, Richmond, VA., USA
Bengmark, S. and S. Bengmark, 2001. Pre-pro-and synbiotics. Curr. Opin. Clin. Nutr. Metab. Care, 4: 571-579. PubMed |
Cavit, A., 2004. Effect of dietary probiotic supplementation on growth performance in the rock partridge ( Alectoris graeca). Turk. J. Vet. Anim. Sci., 28: 887-891. Direct Link |
Chichlowski, M., J. Croom, B.W. McBride, L. Daniel, G. Davis and M.D. Koci, 2007. Direct-fed Microbial primalac and salinomycin modulate whole-body and intestinal oxygen consumption and intestinal mucosal cytokine production in the broiler chick. Poult. Sci., 86: 1100-1106. CrossRef | PubMed | Direct Link |
Chichlowski, M., W.J. Croom, F.W. Edens, B.W. McBride and R. Qiu et al., 2007. Microarchitecture and spatial relationship between bacteria and ileal, cecal and colonic epithelium in chicks fed a direct-fed microbial, PrimaLac and salinomycin. Poult. Sci., 86: 1121-1132. CrossRef | PubMed | Direct Link |
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 |
Denli, M., F. Okan and K. Celik, 2003. Effect of dietary probiotic, organic acid and antibiotic supplementation to diets on broiler performance and carcass yield. Pak. J. Nutr., 2: 89-91. CrossRef | Direct Link |
Duncan, D.B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. CrossRef | Direct Link |
Elwinger, K., E. Berndtson, B. Engstrom, O. Fossum and L. Waldenstedt, 1998. Effect of antibiotic growth promoters and anticoccidials on growth of Clostridium perfringens in the caeca and on performance of broiler chickens. Acta Veterinaria Scandinavica, 39: 433-441. PubMed |
Esteve-Garcia, E., J. Brufau, A. Perez-vendrell, A. Miquel and K. Duven, 1997. Bioefficacy of enzyme preparations containing beta-glucanase and xylanase activities in broiler diets based on barley or wheat in combination with flavomycin. Poult. Sci., 76: 1728-1737. PubMed | Direct Link |
Fairchild, A.S., J.L. Grimes, F.T. Jones, M.J. Wineland, F.W. Edens and A.E. Sefton, 2001. Effects of hen age, Bio-Mos, and Flavomycin on poult susceptibility to oral Escherichia coli challenge. Poult. Sci., 80: 562-571. CrossRef | PubMed | Direct Link |
Friedewald, W.T., R.I. Levy and D.S. Fredrickson, 1972. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin. Chem., 18: 499-502. CrossRef | PubMed | Direct Link |
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 |
Gordon, T., W.P. Castelli, M.C. Hjortland, W.B. Kannel and T.R. Dawber, 1977. High density lipoprotein as a protective factor against coronary heart disease: The Framingham study. Am. J. Med., 62: 707-714. CrossRef | PubMed | Direct Link |
Gunal, M., G. Yayli, O. Kaya, N. Karahan and O. Sulak, 2006. The effects of antibiotic growth promoter, probiotic or organic acid supplementation on performance, intestinal microflora and tissue of broiler. Int. J. Poult. Sci., 5: 149-155. CrossRef | Direct Link |
Ignacio, E.D., 1995. Evaluation of the effect of yeast culture on the growth performance of broiler chick. Poult. Sci., 74: 196-196.
Jamroz, D., A. Wiliczkiewicz, J. Orda, T. Wertelecki and J. Skorupinska, 2004. Response of broiler chickens to the diets supplemented with feeding antibiotic or mannan-oligosaccharides. Elect. J. Polish Agric. Univ., 7: 1-6. Direct Link |
Kabir, S.M.L., M.M. Rahman, M.B. Rahman, M.M. Rahman and S.U. Ahmed, 2004. The dynamics of probiotics on growth performance and immune response in broilers. Int. J. Poult. Sci., 3: 361-364. CrossRef | Direct Link |
Kannan, M., R. Karunakaran, V. Balakrishnan and T.G. Prabhakar, 2005. Influence of prebiotics supplementation on lipid profile of broilers. Int. J. Poult. Sci., 4: 994-997. CrossRef | Direct Link |
Kermanshahi, H. and H. Rostami, 2006. Influence of supplemental dried whey on broiler performance and cecal flora. Int. J. Poult. Sci., 5: 538-543. CrossRef | Direct Link |
Klaver, F.A.M. and R. van der Meer, 1993. The assumed assimilation of cholesterol by lactobacilli and Bifidobacterium bifidum is due to their bile salt-deconjugating activity. Applied Environ. Microbiol., 59: 1120-1124. PubMed | Direct Link |
Nahashon, S.N., H.S. Nakaue and L.W. Mirosh, 1996. Performance of single comb white leghorn fed a diet supplemented with a live microbial during the growth and egg laying phases. Anim. Feed. Sci. Technol., 57: 25-38. CrossRef | Direct Link |
Nayebpor, M., P. Farhomand and A. Hashemi, 2007. Effects of different levels of direct fed microbial ( Primalac) on growth performance and humoral immune response in broiler chickens. J. Anim. Vet. Adv., 6: 1308-1313. Direct Link |
NRC., 1994. Nutrient Requirements of Poultry. 9th Edn., National Academy Press, Washington, DC., USA., ISBN-13: 9780309048927, Pages: 155 Direct Link |
Panda, A.K., M.R. Reddy and N.K. Praharaj, 2001. Dietary supplementation of probiotic on growth, serum cholesterol and gut microflora of broilers. Indian. J. Anim. Sci., 71: 488-490.
Pelicano, E.R.L., P.A. Souza, H.B.A. Souza, A. Oba, E.A. Norkus, L.M. Kodawara and T.M.A. de Lima, 2003. Effect of different probiotics on broiler carcass and meat quality. Brazil. J. Poult. Sci., 5: 207-214. CrossRef | Direct Link |
Pelicia, K., A.A. Mendes, E.S.P.B. Saldanha, C.C. Pizzolante and S.E. Takahashi et al., 2004. Use of prebiotics and probiotics of bacterial and yeast origin for free-range broiler chickens. Braz. J. Poult. Sci., 6: 163-169. CrossRef | Direct Link |
Perreault, N. and S. Leeson, 1992. Age-related carcass composition changes in male broiler chickens. Can. J. Anim. Sci., 72: 919-929. CrossRef | Direct Link |
Piray, A.H., H. Kermanshahi, A.M. Tahmasbi and J. Bahrampour, 2007. Effects of cecal cultures and Aspergillus meal prebiotic (Fermacto) on growth performance and organ weights of broiler chickens. Int. J. Poult. Sci., 6: 340-344. CrossRef | Direct Link |
Ros, E., 2000. Intestinal absorption of triglyceride and cholesterol: Dietary and pharmacological inhibition to reduce cardiovascular risk. Atherosclerosis, 51: 357-379. CrossRef | PubMed | Direct Link |
Santoso, U., K. Tanaka and S. Ohtani, 1995. Effect of dried Bacillus subtilis culture on growth, body composition and hepatic lipogenic enzyme activity in female broiler chicks. Br. J. Nutr., 74: 523-529. CrossRef | PubMed | Direct Link |
SAS, 1998. SAS/STAT User's Guide. SAS Institute Inc., Cary, NC
Schrezenmeir, J. and M. de Vrese, 2001. Probiotics, prebiotics and synbiotics-approaching a definition. Am. J. Clin. Nutr., 73: 361S-364S. PubMed | Direct Link |
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 |
Spring, P., 1999. Mannanoligosaccharide as an alternative to antibiotic use in Europe. Zootecnica Int., 22: 38-41.
Thitaram, S.N., C.H. Chung, D.F. Day, A. Hinton Jr., J.S. Bailey and G.R. Siragusa, 2005. Isomaltooligosaccharide increases cecal bifidobacterium population in young broiler chickens. Poult. Sci., 84: 998-1003. CrossRef | PubMed | Direct Link |
Turnidge, J., 2004. Antibiotic use in animals-prejudices, perceptions and realities. J. Antimicrob. Chemother., 53: 26-27. CrossRef | PubMed | Direct Link |
Willis, W.L., O.S. Isikhuemhen and A. Ibrahim, 2007. Performance assessment of btroiler chickens given mushroom extract alone or in combination with probiotic. Poult. Sci., 86: 1856-1860. PubMed | Direct Link |
Wilson, T.A., R.J. Nicolosi, E.J. Rogers, R. Sacchiero and D.J. Goldberg, 1998. Studies of cholesterol and bile acid metabolism and early atherogenesis in hamsters fed GT16-239, a novel bile acid sequestrant (BAS). Atherosclerosis, 40: 315-324. PubMed |
Woodward, S.A., R.H. Hams, R.D. Miles, D.M. Janky and N. Ruiz, 1988. Research note: Influence of virginiamycin on yield of broilers fed four levels of energy. Poult. Sci., 67: 1222-1224. PubMed |
Wray, C. and R.H. Davies, 2000. Competitive exclusion-an alternative to antibiotics. Vet. J., 159: 107-108. CrossRef | PubMed |
Yalcinkayal, H., T. Gungori, M. Bafialani and E. Erdem, 2008. Mannan oligosaccharides (MOS) from Saccharomyces cerevisiae in broilers: Effects on performance and blood biochemistry. Turk. J. Vet. Anim. Sci., 32: 43-48. Direct Link |
Zulkifli, I., N. Abdullah, N.M. Azrin and Y.W. Ho, 2000. Growth performance and immune response of two commercial broiler strains fed diets containing Lactobacillus cultures and oxytetracycline under heat stress conditions. Br. Poult. Sci., 41: 593-597. CrossRef | Direct Link |
Gowenlock, A.H., J.R. McMurray and D.M. McLauchlan, 1988. Varley's Practical Clinical Biochemistry. 6th Edn., CAS Publishers and Distributors, New Delhi, pp: 477-549
|
|
|
 |