ASSESSMENT OF RESPIRATORY CHAIN COMPLEX ACTIVITIES AND ELECTRON TRANSPORT CHAIN PROTEIN EXPRESSION IN MUSCLE MITOCHONDRIA IN ANGUS STEERS WITH LOW AND HIGH FEED EFFICIENCY

Authors: SANDELIN, B - U AR FAYETTEVILLE; BROWN, A - U AR FAYETTEVILLE; OJANO-DIRIAN, C - U AR FAYETTEVILLE; IQBAL, M - U AR FAYETTEVILLE; BOTTJE, W - U AR FAYETTEVILLE; Brown, Michael; HERRING, W - SMITHFIELD P G GRP, NC; JOHNSON, Z - U AR FAYETTEVILLE; BAUBLITS, R - U AR FAYETTEVILLE

Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/20/2004
Publication Date: 7/25/2004
Citation: Sandelin, B.A., Brown, A.H., Ojano-Dirian, C., Iqbal, M., Bottje, W.G., Brown, M.A., Herring, W.O., Johnson, Z.B., Baublits, R.T. 2004. Assessment of respiratory chain complex activities and electron transport chain protein expression in muscle mitochondria in Angus steers with low and high feed efficiency [abstract]. Joint Abstracts of the American Dairy Science and Society of Animal Science. p. 753.

Interpretive Summary: ABSTRACT ONLY

Technical Abstract: The objectives of this study were to determine the relationships between feed efficiency (FE, gain/feed) and respiratory chain complex activity and mitochondrial protein expression in cattle. Feed efficiency was determined on 92 head of contemporary purebred Angus steers fed over a 130 d period. Individual animal intake was measured by a Calan Broadbent Feeding system. Animals were fed five finishing rations (stepwise) throughout the feeding period. Animals were harvested at a commercial packing plant and muscle (Sternohyoideus) samples were obtained from steers with Low (0.154 ± 0.02, n=7) and High (0.252 ± 0.02, n=7) FE. Muscle homogenate and mitochondria were isolated using differential centrifugation methods. Activities of respiratory chain complexes were measured using spectrophotometric methods. The protein bands were separated in 10% SDS-PAGE, stained with Coomassie blue and intensities were quantified using Scion® software. Mitochondrial protein expressions were assessed with Western blot analysis with a chemiluminescence detection system. Activities of respiratory chain Complexes (I and II) were higher (P < 0.02) in Low compared to High FE steers. While the expression of four immunoreactive mitochondrial proteins, NAD4 (Complex I), core I (Complex II), Cox II (Complex IV), ANT1 (ADP/ATP channels), were higher (P < 0.05) in high compared to the low FE steers there were no difference in the expression of several other proteins. SDS-PAGE revealed that the intensities of seven protein bands were higher in High compared to Low FE animals. It appears that differences in complex activities and protein expressions may be involved in the phenotypic expression of feed efficiency in cattle.