Determination of mitochondrial function and site-specific defects in electron transport in duodenal mitochondria in broilers with low and high feed efficiency.
Duodenal mitochondria were isolated from broiler breeder males with high (0.79+/-0.01, n = 9) and low (0.63+/-0.02, n = 9) feed efficiency (FE) to assess relationships of FE with duodenal mitochondrial function and site-specific defects in electron transport. Sequential additions of adenosine diphosphate (ADP) resulted in 1) higher respiratory control ratio (RCR; an index of respiratory chain coupling) in high FE mitochondria provided succinate, and 2) higher ADP to oxygen ratio (ADP:O; an index of oxidative phosphorylation) in low FE mitochondria provided NADH-linked substrates (malate, pyruvate, or both). Basal electron leak, measured as H2O2 production, was greater in low FE mitochondria provided succinate (P = 0.08) or NADH-linked substrates. As H2O2 levels were elevated in low FE compared with high FE mitochondria by complex I (P+/-0.07) and complex II inhibition, the higher basal electron leak in low FE mitochondria was apparently due to site-specific defects in electron transport at complexes I and II. Elevations in H2O2 above basal levels indicated that high FE mitochondria may also exhibit electron transport defects at complexes I and III. Despite an ability to produce adenosine triphosphate (ATP) that was equal or superior to that demonstrated in high FE duodenal mitochondria, low FE mitochondria exhibited a greater inherent degree of electron leak. The results provide insight into the role that duodenal mitochondria play in the phenotypic expression of FE in broilers.
Ojano-Dirain
C P
CP
Department of Poultry Science, University of Arkansas, Fayetteville, Arkansas 72701, USA. cojano@uark.edu
Iqbal
M
M
Cawthon
D
D
Swonger
S
S
Wing
T
T
Cooper
M
M
Bottje
W
W
D000244:Adenosine Diphosphate / Q000008:administration & dosage / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development; D004386:Duodenum / Q000648:ultrastructure*; D004579:Electron Transport; D006861:Hydrogen Peroxide / Q000378:metabolism; D008293:Malates / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000502:physiology*; D010100:Oxygen / Q000032:analysis; D010101:Oxygen Consumption; D019289:Pyruvic Acid / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism
D008293:Malates; D000244:Adenosine Diphosphate; C030298:malic acid; D019289:Pyruvic Acid; D019802:Succinic Acid; D006861:Hydrogen Peroxide; D010100:Oxygen