An experiment was conducted to study the effect of graded levels of butyric acid (butyrate) on performance, gastrointestinal tract health and carcass characteristics in young broiler chickens. Control starter (0-3 wk) and finisher (4-5 wk) diets were formulated to contain 2,900 kcal ME/kg and 22% CP, and 3,000 kcal ME/kg and 20% CP, respectively. Subsequently, four other experimental diets were formulated to contain 0.05% antibiotic (furazolidone) or 0.2, 0.4 and 0.6% butyric acid. Each diet was fed at random to 8 replicates of 6 chicks each throughout the experimental period (0-5 wk). The results showed that 0.4% butyrate in the diet was similar to antibiotic in maintaining body weight gain and reducing E. coli numbers but superior for feed conversion ratio. No added advantage on these parameters was obtained by enhancing the concentration of butyrate from 0.4 to 0.6% in the diet. Feed intake and mortality were not influenced by the dietary treatments. A reduction in pH of the upper GI tract (crop, proventiculus and gizzard) was observed by inclusion of butyrate in the diets of broilers compared to either control or antibiotic-fed group. Butyrate at 0.4% was more effective in reducing the pH than 0.2% butyrate. Within the lower GI tract, 0.4 and 0.6% butyrate was effective in lowering pH in the duodenum, but no effect was found in either the jejunum or ileum. The villus length and crypt depth in the duodenum increased significantly in all the butyrate treated diets irrespective of the level tested. Carcass yield was higher and abdominal fat content was lower significantly in all the butyrate treatment groups compared to the control or antibiotic group. From these findings, it is concluded that 0.4% butyric acid supplementation maintained performance, intestinal tract health, and villi development and carcass quality in broiler chickens.

No abstract

An experiment was conducted to study the e#ect of dietary supplementation of probiotic Lactobacillus sporogenes (L. sporogenes) on performance and serum biochemico-lipid profile of broiler chickens. One hundred and twenty, day-old commercial broiler chicks were distributed equally into -groups of .* chicks each, which was further replicated to 2 groups of / each. The chicks were placed on one of three dietary treatments : basal, basal with probiotic (0ῌ+* 2 spore of Lactobacillus sporogenes per g) at +** or ,** mg per kg feed. Body weight gain increased and feed conversion ratio improved significantly due to dietary supplementation of +** mg probiotic per kg diet. However, no further benefits on the above parameters could be observed by increasing the level of supplementation from +** to ,** mg per kg. Leg abnormality score is not influenced by probiotic supplementation in the diet. However, the bone breaking strength and bone ash content increased significantly by probiotic supplementation at +** mg per kg diet. The concentration of protein and calcium increased significantly due to dietary supplementation of L. sporogenes. Neither concentration of inorganic phosphorus nor activities of enzymes such as serum glutamate-oxaloacetate transminae (SGOT), serum glutamate-pyruvate transaminase (SGPT) and alkaline phosphatase (ALP) in serum were influenced due to L. sporogenes supplementation. Serum total cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol and triglycerides were reduced significantly by dietary supplementation of L. sporogenes at +** mg per kg diet. However, high-density lipoprotein (HDL) cholesterol of birds was not influenced by L. sporogenes supplementation. It is concluded that dietary supplementation of Lactobacillus sporogenes (0ῌ+* 2 spore per g) at +** mg per kg diet significantly enhanced body weight gain, improved feed conversion ratio, bone ash and bone breaking strength and lowered total cholesterol, VLDL cholesterol and triglycerides concentrations in the serum of broiler chickens.

The residue of cottonseed oil extraction industry popularly known as cottonseed meal (CSM) is a fairly good source of protein (,,,.* to /0*., g kg ῌ+ ) and metabolizable energy (1.. to ++.33 MJ kg ῌ+ ). The use of CSM in poultry diet is limited due to the presence of gossypol, cyclopropenoid fatty acids (CPFA), high fibre and poor protein quality. The most critical amino acid in CSM is lysine. During the oil extraction from cottonseeds, a portion of free gossypol (FG) binds with the epsilon amino group of lysine, thereby reducing the availability of lysine to the chicken. The concentration of nutrients, FG, CPFA in CSM depends on the variety of cultivars, methods of oil extraction, proportion of kernel to husk, lint and seed coat. The concentration of FG in various varieties of CSM ranges from ,** and /-** mg kg ῌ+ . In glandless variety, the FG concentration is less (῍+-* mg kg ῌ+ ). Gossypol inhibits the activity of pepsin and trypsin in gastro-intestinal tract, thereby reducing the digestibility of protein. The reported toxic e#ects of gossypol are growth depression, lameness, decreased egg size and hatchability. Gossypol and CPFA also deteriorates the internal egg quality by causing yolk mottling and pinkish discoloration of albumen, respectively. The tolerance levels of FG in birds vary widely depending on the age and strain of birds, protein content and quality, duration of feeding, presence of minerals especially the iron content in the diet. The tolerance of FG in chicks varies widely (3* to +*** mg kg ῌ+ diets), however performance of layer chicks could be a#ected even at a lower FG intake of ,.*, mg day ῌ+ bird ῌ+ . Though, growth was not a#ected in broilers at FG concentration in diet below +/* mg kg ῌ+ , feed e$ciency was reduced at lower levels i.e. 0*῎+** mg kg ῌ+ . The depression in egg production in layers fed diets containing more than +** mg kg ῌ+ was mainly due to lowered feed intake. The egg weight and egg quality was not a#ected at FG levels upto ,** mg kg ῌ+ diet. Iron treatment (.:+; Fe:FG) proved to be e#ective in alleviating the negative e#ects on egg quality, but could not alleviate the depression in laying performance. Lysine supplementation to CSM containing diets is also e#ective in counteracting the ill e#ects of FG in chicken, especially chicks and broilers. Other processing methods like solid substrate fermentation, production of glandless cotton seed and use of organic solvents were though e#ective in improving the nutritive value of CSM and reducing the FG content in CSM, these methods are of little practical relevance and uneconomical. Production of glandless variety of cottonseed through genetic modification (Bacillus thuringiensis cotton) is one of the recent trends of reducing the FG content. Some other methods like pelleting, extrusion, cooking and Ca (OH), treatment of CSM could be tried for improving the feeding value of CSM in poultry.

An experiment was conducted with broiler (Cobb 400) male chicks (n = 480) to determine the effect of betaine (Bet) supplementation (0 and 800 mg/kg) to diets containing five concentrations (15, 18, 20, 22 and 24 g/kg crude protein, CP) of methionine (Met) in a 2×5 factorial study for performance, carcass traits, immune responses, and serum parameters. Each diet was fed ad libitum from 1 to 42 d of age to 8 replicates of 6 chicks. Birds were housed in battery brooders placed in an open-sided poultry shed. Body weight gain, feed intake, feed conversion efficiency and slaughter variables were recorded at 21 and 42 d of age. Serum biochemical profile, antibody production against Newcastle disease (ND) and lymphocyte proliferation ratio (LPR) were analysed at 42 d of age. Supplementing Bet to diets containing sub-optimal concentrations of Met (15 g/kg) improved weight gain and breast yield at 21 d of age (p<0.01), and feed conversion efficiency at 42 d of age (p<0.05). Feed efficiency at 21 d of age, body weight gain at 42 d of age, slaughter variables except breast yield at 21 d of age and ND antibody titres were not affected (p>0.05) by the interaction. LPR increased (p<0.05) with Bet supplementation at 20 g Met/kg CP equal to those broilers fed 24 g Met without Bet. Bet supplementation enhanced the concentrations of protein, globulin and cholesterol in serum of broilers fed sub-optimal concentrations of Met. Results suggested that Bet supplementation (800 mg/kg diet) enhanced growth (21 d), feed conversion efficiency (42 d), breast yield and lymphocyte proliferation in broilers fed a diet containing 15 g Met/kg CP.