Relationship between the activity of mitochondrial respiratory chain complexes and feed efficiency in fat-tailed Ghezel lambs1

Abstract

This study was conducted to investigate relationships between mitochondrial respiratory chain complex activities, feed efficiency, and carcass traits in sheep. A group of Ghezel male lambs sired by a single ram were randomly allotted to individual pens. The lambs were fed ad libitum with a fattening diet containing 30% roughage (corn silage and alfalfa hay) and 70% concentrate for 70 d to individually phenotype each lamb for feed conversion ratio (FCR), adjusted FCR (aFCR), and residual feed intake (RFI). The lambs were then humanely killed and the liver, abdominal fat, pelvic fat, cardiac fat, warm carcass weight, and cold carcass weight, as well as the cross-sectional area of the LM and the fat depth over the 12th rib, were determined. A portion of LM was obtained to determine mitochondrial protein and respiratory chain complex activities (complexes I to V). Statistical analysis was carried out based on lambs exhibiting high and low RFI (n = 8), FCR (n = 8), or aFCR (n = 8) phenotypes. The lambs exhibiting the high-RFI phenotype consumed 110 g more feed daily (P < 0.05) than did the phenotype exhibiting low RFI, with no difference in ADG. Conversely, there was no difference in feed intake between the low- or high-FCR groups, but sheep exhibiting the low-FCR phenotype gained 70 g more (P < 0.05) per day compared with those exhibiting the high-FCR phenotype. It was determined that all 5 respiratory chain complex activities were greater (P < 0.05) in sheep exhibiting the low-RFI phenotype compared with those exhibiting the high-RFI phenotype, with significant (P < 0.001) negative correlation coefficients between RFI and respiratory chain complex activity. When efficiency was assessed using FCR, only activities of respiratory chain complexes III, IV, and V were less (P < 0.05) in the low-FCR phenotype compared with the high-FCR phenotype, and there were no differences (P > 0.1) in respiratory chain complex activities between groups when FCR was adjusted for metabolic BW (aFCR). There were no differences (P > 0.1) in carcass traits among any of the feed efficiency phenotypes. The results suggest that the inclusion of respiratory chain complex activities in breeding programs may be helpful in selecting for sheep exhibiting the low-RFI phenotype.

Epigenetics and developmental programming of welfare and production traits in farm animals

“…the gut has a very rapid turnover) is not known. It is interesting to note that comparing high-and low-feed efficiency or residual feed intake (RFI) in sheep (Sharifabadi et al 2012) indicates reduced mitochondrial respiration in muscles from the more efficient animals. This appears to involve reduced BMR and is associated with genes encoding mitochondrial proteins, suggesting that oxidative metabolism and/or efficiency of ATP synthesis may be key.…”

Hepatic mitochondrial efficiency in lines of mice differing in feed intake12

“…Since these studies relating mitochondrial parameters to feed efficiency traits were reported, other authors have continued research into the sub-cellular network contributing to economically important production traits in laboratory and livestock species. Sharifabadi et al (2012) were able to study the activities of the various mitochondrial complexes and relate them to different feed efficiency traits in fat-tailed Ghezel lambs. For this study, 25 lambs from the same sire were placed on a feed intake trial and were grouped according to high and low RFI and high and low FCR.…”

“…After analyzing the RFI group it was determined that low RFI lambs had greater activity at all 5 membrane complexes studied. When analyzing the FCR group they determined that low FCR lambs had greater activity at complexes III, IV, and V. Sharifabadi et al (2012) noted that including information about mitochondrial complexes may be useful to breeding programs selecting animals for feed efficiency. from all 3 replicates of Generation 58 were analyzed.…”

“…They found significant differences in mitochondrial efficiency between high and low feed efficient animals. Sharifabadi et al (2012) identified lambs displaying high and low feed efficiency and then examined the activity of Complexes I, II, III, IV, and ATP Synthase. They found that all 5 complexes exhibited greater activity in sheep displaying the low RFI phenotype.…”

Swine blood transcriptomics: Application and advancement

“…Mitochondria play important roles in many biological processes, including fatty acid metabolism, amino acid metabolism, and steroidogenesis [275]. Importantly, mitochondrial function has been associated with feed efficiency in poultry, cattle and lambs [276,277]. As well, it has been shown that the mitochondrial proteome profiles are different between these low and high RFI lines of pigs and the mitochondria from the liver and LD muscle of the low RFI pigs produced less ROS [149][150][151].…”