L-carnitine supplementation in breeding pigeons: impact on zootechnical performance and carnitine metabolism

In the first experiment (Exp1), three consecutive breeding rounds were perf ormed by two groups of six pigeon couples in order to study the impact of L -carnitine supplementation (80 mg.d(-1)) of parent pigeons on zootechnical performance. Both in the second and third experiments (Exp2, Exp3), one bre eding round was performed by two groups of six pigeon couples to reveal the biochemical background of the increase in squab growth, the limitation of body weight decrease in male parent birds and the tendency for an improved cumulative feed efficiency due to L-carnitine supplementation in Exp1. Grow th improvement of the squabs with L-carnitine was only seen when the parent pigeons were supplemented, together with a marked rise in the body weight of the parent birds around hatching. Based on the results of the crop milk analysis, growth improvement was probably due to a quantitative impact on c rop milk production. The crop milk from the supplemented groups in both Exp 2 and Exp3 had increased levels of carnitine. Carnitine, gamma -butyrobetai ne and acetylcarnitine were increased in plasma samples of the supplemented parent pigeons. No differences were present in the squabs' plasma for thes e parameters. In the squabs of Exp3, no changes were seen in the proportion al growth or the protein content of the heart, breast muscle and liver, but the breast muscle of the squabs from the supplemented group in Exp3 showed a considerable rise in carnitine and a marked decrease in gamma -butyrobet aine.