Effects of dietary energy density and L-carnitine supplementation on growth performance, carcass traits and blood parameters of broiler chickens

The present study was conducted to determine the effects of dietary metabolisable energy (ME) density and L-carnitine supplementation on the performance, carcass traits and blood parameters of broiler chickens. The experiment was designed with three levels of dietary energy (low, medium and high) and two levels of L-carnitine (0 and 100 mg/kg diet) in a 3x2 factorial arrangement. L-carnitine supplementation did not significantly affect body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR). However, FCR and BWG showed a significant improvement as dietary energy density increased. No significant interactions were observed between energy density and L-carnitine supplementation in the performance and carcass parameters studied in the study. Carcass yield and proportion of carcass sections were not affected significantly by any of the treatments. Chemical composition of the leg (thigh and drumstick) and breast muscle was not significantly influenced by dietary energy or carnitine, with the exception of the dry matter (DM) content of breast muscle. A low ME diet caused a significant increase in the DM content of chicken breast muscle. Furthermore, blood parameters did not show any differences between treatments. However, aspartate aminotransferase (AST) activity in blood was elevated in chickens fed a high ME diet compared to those on a low ME diet. The results of the investigation showed that L-carnitine supplementation produced no significant improvement in broiler performance and meat quality. Higher levels of diet ME increased broiler performance, though no significant interactions could be found between energy and carnitine levels. South African Journal of Animal Science Vol. 37 (2) 2007: pp. 65-7