Effect Of Peptide And Cysteamine On Growth Performance And Mechanism In Broilers

This study was conducted mainly to investigate the effect of small peptide and cysteamine on productivity in broilers, and to discuss its mechanism by measuring the apparent nutrient availability, blood biochemical parameters, digestive enzyme activities and carcass quality.The method of 3×3 double-factor factorial design was adopted. One-day-old robust 1080 Ross 308 broilers were randomly divided into nine treatments. Each treatment included four replicates of 30 broiler chickens per repeat.Group 1(control group) was fed basal diet; treatment group 2 and 3 was added 0.5% and 1.0% of small peptide respectively, and feed nutrition levels were adjusted to consist with basal diet; treatment group 4 was added 90mg/kg of cysteamine in the basal diet; treatment group 5 was added 90mg/kg cysteamine in the diets of the treatment group 2; treatment group 6 was added 90mg/kg cysteamine in the treatment group 3; treatment group 7 was added 120mg/kg cysteamine in the basal diet; treatment group 8 was added 120mg/kg cysteamine in treatment group 2 diet; treatment group 9 was added 1% small peptide and 120mg/kg cysteamine in the group 3. This study lasted 42 days, and slaughter test and metabolic test were conducted after feeding test. The results were as follows:1. Interaction between small peptide and cysteamine were significant on average daily gain and F/G(feed gain ratio)(P<0.05). Treatment group 5(0.5% small peptide and 90mg/kg cysteamine) had the highest average daily gain and 11.36% higher than the control group. Treatment group 5 had the lowest F/G and was 8.60% lower than the control group. Treatment group 3, 4, 6, 7, 8 was 5.29%, 5.04%, 6.34%,4.57% and 6.34% higher in ADG(average daily gain) than the control group(P<0.05), respectively. Treatment group 3, 4, 6, 8, 9 was 4.84%, 4.30%, 4.84%, 4.84% and 5.38% lower in F/G than the control group(P<0.05). Adding 1% small peptide or 90mg/kg cysteamine could significantly reduce F/G of broilers(P<0.05).2. Interaction between cysteamine and small peptide were significant on apparent nutrient availability of crude protein and crude fat(P<0.05). Apparent nutrient availabilities of crude protein and crude fat of treatment group 5 was significantly 9.68% and 8.00% higher than the control group respectively. Adding 90mg/kg cysteamine or 0.5% small peptide could significantly increase apparent nutrient availability of crude protein and crude fat in broiler diets(P<0.05). Interaction between small peptide and cysteamine were significant on somatostatin serum total protein content of broilers(P<0.05). Treatment group 5 had the highest total protein level and had the lowest somatostatin content than the control group(P<0.05). Interaction between small peptide and cysteamine were significant on total protease activity of broiler serum(P<0.05). Total protease and amylase of treatment group 5 had the highest activities than the control group, increased by 9.71% and 11.27% respectively.3. Adding cysteamine could significantly improve the slaughter rate, half eviscerated rate, eviscerated rate, breast muscle rate and leg muscle rate of broilers(P<0.05).In conclusion, adding small peptide and cysteamine in Ross 308 broiler basal diet had significant interactive effects in promoting growth, improving feed efficiency and meat quality.