Impact of Dietary Excess Methionine and Lysine with or Without Addition of L-Carnitine on Performance, Blood Lipid Profile and Litter Quality in Broilers

Effects of excess of dietary methionine (6.5 and 8.5 g kgG1 diet) and lysine (13.5 and 15.5 g kgG1 diet) on performance, blood lipid profile and litter quality of broiler chickens fed corn-soybean meal based diet with or without supplementation of L-carnitine with two levels (175 and 350 mg kgG1 diet) were investigated. Two hundred forty one day old chicks (Cobb) of mixed sex were housed in pens littered with horse-bean straw. Three replicates of eight dietary treatments (10 chicks per replicate) were randomly distributed. Dry matter content of litter and excreta were done weekly. The results showed that the group supplemented with surplus of methionine and lysine (6.5-13.5 g kgG1 diet) without supplementation of L-carnitine had the highest body weight and body weight gain. L-carnitine either 175 or 350 mg kgG1 diet had significantly lower lipid profile parameters in serum than groups without supplementation L-carnitine. Moreover, the broilers fed high levels of lysine and methionine with surplus amount of L-carnitine (350 mg kgG1 diet) led to significantly lower cholesterol level vs. low L-carnitine. The experimental group supplemented with highest level of methionine and lysine (8.5-15.5 g kgG1) had lowest malondialdehyde and highest reduced glutathione levels and total antioxidant capacity. No marked differences were found in dry matter content of the excreta and litter among the experimental treatments (mean; 23.8±2.50 and 66.6%±11.2, respectively). Interestingly, dietary L-carnitine supplementation had no effects on foot pad health even with using surplus level of it.