Due to price volatility of highly digestible but expensive protein sources like SBM future poultry diets will be formulated by using cheap and less digestible protein sources including CM and SFM due to price volatility. Undigested protein in hind gut subjected to microbial fermentation, resulted into formation of nitrogenous products, which are not only harmful to birds, but also excreted in litter bedding and generate ammonia, nitrous acid and nitrous oxide, the latter is powerful greenhouse gas with an effect about 300 times that of carbon dioxide. The potential solution to this problem is supplementation of synthetic amino acids (nearly 99 % digestible) in low nutrient density (crude protein) formulated by using cheap and less digestible protein sources. Therefore, objectives of current experiment were to determine the impact of digestible Lys, Methionine + Cysteine (M + C) ratios from different protein sources on production efficiency, carcass characteristics, gut development and total tract digestibility of protein in broilers. In total, mixed sex Ross 308 day old broilers were randomly assigned to 9 dietary treatments with replication of 6 replicates per treatment and 8 birds in each replicate. 1) Control corn soy based diet, 2) Canola meal (CM) based high crude protein ( 21% during starter phase and 19% during grower phase) diet with ideal protein ratio (IPR), 3) CM based high protein diet with 0.05 supplemented ( M + C ), 4) CM based low protein (19% during starter phase and 17% during grower phase) diet with IPR, 5) CM based low protein diet with 0.05 supplemented ( M + C ), 6) Sunflower meal (SFM) based high protein diet with IPR, 7) SFM based high protein diet with 0.05% supplemented (M + C), 8) SFM based low protein diet with IPR and 9) SFM based low protein diet with 0.05 % supplemented (M + C). All diets were fed as mash form in two phases (Starter 1-21 days and Grower 22-42 days). Feed and water were provided ad libitum throughout the experimental period. Celite @ 2% were used an inert marker for digestibility
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SUMMARY
SUMMARY
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study. Average body weights, FCR, mortality rate were recorded from each replicate for the estimation of production efficiency factor. At 42 day, fresh excreta were collected from each replicate and 2 birds from each replicate were randomly selected and slaughtered for carcass and gut measurements. Crude protein and acid insoluble ash (AIA) in feed and excreta samples were determined. The results of the present study indicate that the protein sources showed non-significant difference on production efficiency and gut development, however, significant difference was observed on carcass characteristics and total tract digestibility. The birds fed higher CP level showed significant difference on production efficiency, carcass characteristics and total tract digestibility of protein. Amino acid supplementation showed significant difference on production efficiency, carcass characteristics, gut development and total tract digestibility of protein. In this study, CM and SFM showed poor performance regarding production efficiency, protein digestibility, gut development and carcass characteristics compared with SBM. However, the supplementation of Meth had improved the performance. It can be concluded that Meth supplementation may improve the overall performance in broilers fed poorly digestible protein source (CM and SFM).
Further research is needed to evaluate the different strategies to improve the digestibility of poorly digestible protein sources including guar meal. Threonine also has an important role in gut development, so there is a need to study the effects of supplementation of threonine above the recommended levels in broilers fed poorly digestible protein sources. There is a need to evaluate the other protein sources that may replace SBM in broilers.