MITOCHONDRIAL RESPIRATORY METABOLISM AND GROWTH-PERFORMANCE OF LAMBS .2. OXYGEN-CONSUMPTION AND OXIDATIVE-PHOSPHORYLATION

Variation in mitochondrial respiratory metabolism, and associations of mitochondrial characteristics with growth traits, were studied in Mer inolandschaf (n = 31) and Rhoenschaf (n = 27) lambs, as well as their reciprocal crosses--Rhoenschaf males x Merinolandschaf females (n = 25 ) and Merinolandschaf males x Rhoenschaf females (n = 31). Significant genotype effects were detected for all the growth parameters studied. Genotype was also significant for succinate-mediated state 3 respirat ion of liver mitochondria (p < 0.01), and approached significance for ATP production with succinate as substrate and glutamate/malate-mediat ed state 3 respiration. Significant trial effects (p < 0.001) were obs erved for all but one of the biochemical parameters studied. Variable patterns of significant correlations between biochemical characteristi cs and growth traits were detected, which were linked to performance l evels of purebred and crossbred lambs. These results indicate that mit ochondrial genes could influence growth in lambs via mitochondrial res piratory metabolism.