Effect Of MHA And Betaine On Performance Of Broilers And Serum Index Under Heat Stress Conditions

A 3×4 factorial randomized grouping design was used to investigate effect of betaine and methionine sources (DL-methionine and MHA-FA). 2-3 week, each group was fed with diets of 0, 690 and 1380mg/kg betaine chloride; 750, 1500, 2250 mg/kg MHA-FA and 2000mg/kg DL-Met respectively. 4-7 week, each group was fed with diets of 0, 345 and 690mg/kg betaine chloride; 375, 750, 1125 mg/kg MHA-FA and 1000mg/kg DL-Met respectively. 144 1-day-old health Arbor Acre broilers were randomly divided into 12 groups with four replicates each treatment having three chickens each replicate. In cage rearing, rearing experiment, metabolic trial and acute heatstress trial were conducted to investigate effect of betaine and MHA-FA on performance and serum biochemical indices.The results showed that:During 2-3 weeks, chickens supplemented with 1380mg/kg betaine chloride and 2000mg/ kg Met had optimal daily weight gain and feed conversion ratio (FCR) than other groups. Feed intake, daily weight gain and feed conversion ratio of Met group are higher than ones of three MHA-FA groups without betaine chloride.Chickens receiving 690mg/kg betaine chloride and 1500mg/kg Met had optimal FCR than other groups of all MHA-FA groups. Diet with betaine replacing 1/3 supplementary MHA-FA in equimolar basis could receive better FCR.During 4-7 weeks, supplimental 690mg/kg betaine chloride could increase feed intake, daily weight gain and FCR of chicks.Under acute heat stress, supplimental 690mg/kg betaine chloride could increase feed intake, daily weight gain and FCR of chicks.Under acute heat stress, supplementary betaine chloride could variously maintaine levels of Na⁺, K⁺ and Cl^- in serum, reduce the output of CO₂, slow the decline of HCO₃^- content, pH increase and maintain the balance of electrolyte in serum.Under acute heat stress, supplementary betaine chloride could variously decrease levels of glucose, triglyceride in serum.Under acute heat stress, supplementary betaine chloride could reduce the level of CK, LDH and AST in serum.It indicated that betaine plays a role in protecting of structure of cell memberane.