ABSTRACT
Carnitine has antioxidant properties that protect sperm membranes against toxic reactive oxygen species. Carnitine also functions to reduce the availability of lipids for peroxidation by transporting fatty acids into the mitochondria for beta-oxidation to generate adenosine triphosphate (ATP) energy. Because the effects of this supplemental amino acid on the reproductive performance of the avian breeder male are unknown, the objective of the current study was to evaluate the antioxidant role of dietary L-carnitine on semen traits and testicular histology in Leghorn breeder roosters. Two experiments were conducted in which birds were fed a control diet or one supplemented with 500 mg of carnitine/kg of diet. For Experiment 1, dietary treatments were fed to older birds (n = 12 birds/treatment) when they were 58 to 62 wk of age. For Experiment 2, younger birds were fed dietary treatments between 32 to 37 wk of age (n = 14 experimental units/treatment with three roosters composing an experimental unit for a total of 84 roosters). Semen traits and lipid peroxidation of sperm, determined by measuring malonaldehyde, were examined weekly. Feeding dietary carnitine to young and aging White Leghorn roosters ad libitum for 5 wk not only improved sperm concentration during the last half of supplementation but also reduced sperm lipid peroxidation. Testicular tissue of birds fed dietary carnitine for 5 wk was preserved as indicated by a reduction in multinucleated giant cells. These results suggest that dietary carnitine has antioxidant properties that may preserve sperm membranes in roosters, thereby extending the life span of sperm.