摘要：

To determine the effects of temperature and dietary on the key enzymes regulating , 24 wether were exposed to three temperature treatments (+23 degrees C warm, 0 degrees C cold, or cold-pairfed) and fed either a control -based diet or a supplemented diet for a 5-wk period. After slaughter, tissue samples were collected and frozen for analysis for and enzyme abundance. Thermal environment or supplementation did not affect (P > 0.05) (ACC) activity in longissimus dorsi (LD) muscle. In liver, cold exposure increased (P < 0.05) while supplementation depressed (P < 0.05) ACC activity. In subcutaneous (SC) and mesenteric (MS) adipose tissue ACC activity was not affected (P > 0.05) by cold exposure. Dietary supplementation increased (P < 0.05) ACC activity in both SC and MS but the increase in perirenal (PR) fat was not significant. Western-blot analysis with -labelled identified two isoforms of ACC (280 and 265 kDa) in LD muscle and the 280 kDa was the more abundant isoform. In liver and adipose tissues only one isoform (265 kDa) was identified but there was a poor relationship between enzyme abundance and activity. Neither environment nor diet affected () activity in LD or liver. Cold exposure reduced (P < 0.05) activity in SC tissue of ad libitum fed but increased activity in MS tissue of pair-fed and had no effect in PR fat. Dietary supplementation reduced (P < 0.05) activity by 30% in all three fat depots. A single isoform of with MW of 260 kDa was present in all tissues examined with cold exposure increasing expression in all tissues. The results indicate that temperature and dietary affect enzyme with differential responses in different tissues.

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