Dietary Supplementation of novel feed additives in broilers

Poultry occupies an important place in Indian economy contributing more than INR 11,000 crores to the national GDP. The country ranks 3rd in egg and 5th in chicken meat production (as per USDA data). Per capita availability of poultry meat is 2.15 kg/annum which is less compared to the recommendation of 11 kg meat/annum given by National Institute of Nutrition (Prabhakaran, 2012). Feed forms the major component of total expenditure (about 70-80 per cent) of poultry business (Asghar et al.,2000). Amongst all regularly used growth promoters, antibiotics were the most common feed additives. However, lately use of antibiotics is not only restricted but also have been banned in many countries due to various reasons like alteration of natural gut micro-biota and emerging drug resistance in bacteria and humans (Botsoglou et al., 2002). Consequently, the use of natural promoters such as probiotics, prebiotics, synbiotics, enzymes, toxic binders, organic acids, oligosaccharides, phytogenics, and other feed additives, to enhance the growth and performance of broiler chickens have been advocated (Borazjanizadeh et al., 2011).
Probiotics-live microorganisms, which when administered in an adequate amount confer a health benefit on the host (Anon., 2001). It act in following ways:
1) They get adhered to the different binding sites of the intestinal epithelium thus compete with pathogenic harmful bacteria
2) They produce bactericidal substances
3) They are responsible for stimulation of immune system (Menten, 2002).
Prebiotics can either significantly modulate the colonic microbiota by increasing the number of specific beneficial bacteria such as lactobacilli and bifidobacteria (Rycroft et al., 2001) or reducing undesired intestinal colonization of pathogenic bacteria by mimicking their attachment sites on the intestinal mucosa (Iji and Tivey, 1998).
Synbiotics are a mixture of probiotics and prebiotics that beneficially affects the host by activating the metabolism of one or a limited number of health promoting bacteria and/or by stimulating their growth, improving the host’s welfare (Gibson and Roberfroid, 1995). Recent studies have shown that synbiotic beneficially effects the host by improving the survival and establishment of live microbial dietary supplements in the gastrointestinal tract (Trachoo et al., 2008). Scarce information is available regarding the overall effect of adding synbiotic product to broiler diets on different growth and health parameters in broiler chickens. Therefore this article reviews the beneficial effect of dietary supplementation of probiotic, prebiotic and synbiotic on performance of birds.
Prebiotic is a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or more bacteria in the colon and thus improves host health. Beneficial bacteria could provide both health benefits to the animal and indirect benefits to human health such as reduction of pathogenic bacteria in/on the animal. The dominant prebiotics are Mannan oligosaccharides (MOS), Fructo-oligosaccharide products (FOS, oligofructose, and inulin). However, Trans-galacto-oligosaccharides, gluco-oligosaccharides, glycol-oligosaccharides, lactulose, lactitol, malto-oligosaccharides, xylo-oligosaccharides, stachyose, raffinose, and sucrose thermal oligosaccharides have also been investigated. MOS act by binding and removing pathogens from the intestinal tract and stimulating the immune system (Patterson and Burkholder, 2003).
Probiotic contains yeast cells, bacterial cultures or both that stimulate microorganisms capable of modifying the gastrointestinal environment to favor health status and improve feed efficiency.
Microbial species used as probiotic products:
Probiotics can either be included in the pelleted feed or produced in the form of capsules, paste, powder or granules which can be used for dosing animals directly or through their feed. Target species are cattle, sheep, goats, pigs, poultry, horses and domestic pets. Species currently being used in probiotic preparations are Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus helveticus, Lactobacillus lactis, Lactobacillus salivarius, Lactobacillus plantarum, Streptococcus thermophilus, Enterococcus faecium, Enterococcus faecalis, Bifidobacterium bifidum, Bifidobacterium longum and Saccharomyces cerevisiae (Fuller, 1989).
Synbiotics refer to nutritional supplements combining probiotics and prebiotics and in form of synergism. Main reason for using a synbiotic is that a true probiotic, without its prebiotic food, does not survive well in the digestive system. As prebiotics provides a great place for probiotics to thrive, the population of good bacteria is known to preserve. Studies have shown that by harnessing both the benefits of these prebiotics and probiotics into synergy, the number of good bacteria in the digestive systems increased many folds which results in health benefits.
Results of a feeding trial
In a recently conducted trail, two hundred and forty numbers of one day old chicks were allotted randomly in to four dietary treatments with three replicates of 20 chicks each viz. T1 ( control ), T2, T3 and T4 containing basal feed , basal feed supplement with prebiotics ( Nutriform @ 500 g/ ton ), probiotics ( Protexin @ 100 g / ton ) and synbiotics ( Nutriform @ 250 g/ton + Protexin @ 50 g/ton ), respectively. Feeding experiment was carried out for 42 days and different parameters evaluated includes feed intake, weight gain and feed conversion ratio.
The overall feed intake (g) was significantly (P<0.05) higher in treatment groups as compared to control with highest value was observed in synbiotics supplemented group. Final body weight (g) was significantly ( P<0.05) higher in treatment groups as compared to control. However, amongst different treatment group, statistically significant ( P<0.05) and higher values were observed in prebiotics and synbiotics supplemented group as compare to probiotics supplemented group. FCR was also found to be significantly ( P<0.05) lower in treatment groups as compared to control. While, amongst different treatment groups, statistically significant ( P<0.05) and lower values were observed in prebiotics and synbiotics supplemented group as compared to probiotics supplemented group.
Thus, in conclusion, one may say that supplementation of the combination of prebiotics ( Nutriform @ 500 g/ ton ) and synbiotics ( Nutriform @ 250 g/ton + Protexin @ 50 g/ton ) in the diet of broiler birds improves the feed intake and growth performance. It needs to be included in the diet of boilers up to 42 days of growth period.

by S.R. Bhagwat, S.S. Patil, H.H. Savsani, D.D. Garg, M.R. Chavda and Oliva Das
Dept. of Animal Nutrition, JAU