Effects Of Antimicrobial Lipopeptides On Performance,Nutrient Metabolism And Antioxidant Capacity In AA Broilers

The purpose of this work was to explore the effects and mechanisms of antimicrobial lipopeptides on the performance and physiological function of AA Broilers. Some results from this work could supply information for further exploitation and optimal level of antimicrobial lipopeptides as a new functional feed instead of antibiotic additive in poultry diets. The study included three experiments and the results were demonstrated as follows.Experiment1was designed to study the effect of antimicrobial lipopeptides on performance, carcass characteristic and immunity of broilers.6001-day-old AA broilers were randomly divided into5groups. The diet of each group was as follows: the control diet (C); the control diet+antibiotics (AC); the control diet+4000U/kg antimicrobial lipopeptide (I); the control diet+8000U/kg antimicrobial lipopeptide (II); the control diet+12000U/kg antimicrobial lipopeptide (Ⅲ). The results showed: Compared to group AC, the ADG of group I increased by3.77%(P＜0.05), F/G of group I decreased by4.94%(P＜0.05). The abdominal fat weight ratio and fat width also increased significantly. Compared to group C and AC, the ADFI of group III decreased by3.82%and4.28%(P＜0.05), F/G also decreased significantly. Compared to group C, the level of T4in serum decreased by29.31%(P＜0.05) in21d while the level of TSH in45d of group II increased by72.2%(P＜0.05). T3in groups I and III increase significantly. The index of fabricius and thymus increased by41.48%(P＜0.05) and69.91%(P＜0.01). It indicated that antimicrobial lipopeptides,espeically adding4000U/kg could improve growth and immunity of broilers.Experiment2was designed to study the effect of antimicrobial lipopeptides on antioxidation performance and serum biochemical of broilers. Treatments were the same as the first part. The results showed:The level of T-AOC in serum of group I increased by44.40%(P＜0.05) than group AC in21d,57.87%(P＜0.05)than group C in45d, in group I and II increased by57.87%(P＜.05) and60.62%(P＜0.01)than group C in42d. The level of SOD in liver of group I increased by13.31%(P＜0.05) than group AC. The level of SOD in serum of group Ⅱ increased by38.14%and47.84%(P＜0.05) than group C in21and42d. The level of T-AOC in serum of group Ⅱ increased by60.62%(P＜0.01) than group AC, the level of MDA in serum of group Ⅱ decreased by23.61%(P＜0.05) in45d. The level of FFA in serum of group I decreased by31.14%(P＜0.01) and20.42%(P＜0.05) than group C and AC in21d,50.41%(P＜0.01) and29.93%(P＜0.05) than group C and AC in45d. The level of TG in serum of group I increased by34.29%(P＜0.05). The level of TP in serum of group I increased significantly and the level of ALB in serum of group I decreased significantly. The GOT and GPT in serum of group III was higher but not significantly than other groups (P>0.05) in21d. There is not significant deviation between each group at UN and TC. It indicated that the adequate level of antimicrobial lipopeptides (8000U/kg) could improve antioxidation performance and serum biochemical of Broilers. But add12000U/kg antimicrobial lipopeptides might inhibit antioxidation performance. Antimicrobial lipopeptides could affect lipid and protein metabolism, there is no significantly side effect to broilers.Experiment3was designed to study to study the effect of antimicrobial lipopeptides on the organ index, apparent utilization of nutrients, and digestive enzyme activity in broilers. Treatments were the same as in the first part. The results showed:the level of lypase in group I elevated by37.46%、64.44%、39.83%and45.22%than others groups. the level of disaccharidase and trypsin also elevated but not significantly. The level of amylase in group III elevated by69.44%(P＜0.05)than group AC. The utilization of CP in group I elevated by10.98%and10.38%(P＜0.05) than group C and AC in21d,14.89%and13.66%(P＜0.05) in45d. The utilization of CF in group Ⅰ Ⅱ and Ⅲ was higher than group I and II. The bowel index and weight in group I was higher than other groups. It indicated that antimicrobial lipopeptides could improve digestion function,elevate digestive enzyme activity and apparent utilization of nutrients.Adding4000U/kg antimicrobial lipopeptides could gain best effectiveness in group IIn summary, the work indicated that antimicrobial lipopeptides have a better performance in the regard of growth performance and immunity than traditional antibiotic. Adding appropriate antimicrobial lipopeptides could elivating antioxidation performance of broilers, Regulating protein and fat metabolism, improving digestive function. There is no obvious negative effects of antimicrobial lipopeptides on broilers.