Hepatic Mitochondrial Activity in Two Breeds of Chicken

Respiration rates and efficiencies of oxidative phosphorylation of hepatic mitochondria from mature Hubbard White Mountain Cross broiler and White Leghorn layer hens were compared. Broiler hen mitochondria consistently tended to exhibit higher succinate-supported State 3 respiration rate, respiratory control ratio, and ratio of adenosine diphosphate to oxygen, although breed differences were not statistically significant. Within-breed variation in mitochondrial activity was not associated with body weight or egg production. Hepatic tissue of broiler hens yielded significantly more protein in the mitochondrial fraction than tissue of layer hens. In vitro mitochondrial mixtures representing equal wet tissue weights from each breed showed mitochondrial activity intermediate between the two breeds.