Changes in the expression of regulatory enzymes associated with anabolic pathways of energy metabolism in wild and New Zealand rabbits during feed restriction

摘要

The aim of this work was to study changes in the expression of regulatory enzymes associated with anabolic pathways of energy metabolism in rabbits during feed restriction. For this purpose we used a wild rabbit (WR) breed and a highly meat selected breed (New Zealand rabbit-NZ), so as to understand the pathways for energy utilization under nutritional stress condition in highly productive and on low growth performance rabbit breeds, representing, within this specie, significantly different metabolic capacities. During a period of 30 days NZ and WR experimental breeds were subjected to respectively 40% and 60% reduction of ad libitum feeding, which led to a weight loss of 17.7% and 21.1% of the initial weight. Hepatic gluconeogenic (pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase, and glucose-6-phosphatase), lipogenesis (acetyl CoA carboxylase) and glycogen phosphorylase regulatory enzymes mRNA levels were determined. Hepatic acetyl CoA levels were also measured. Our results show that hepatic pyruvate carboxylase mRNA levels were only affected by breed variations. The NZ animals were unaffected by the feed restriction regarding glucose-6-phosphatase and glycogen phosphorylase transcription level revealed an increase in the mRNA levels of phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and a decrease in acetyl CoA carboxylase. Restricted fed wild rabbits presented a decrease in the mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase over controls, and an increase in the mRNA expression level of acetyl CoA carboxylase. Acetyl CoA levels revealed only breed effect. These results, highlighted a depressed gene expression, over controls, of three of the studied enzymes in the WR restricted fed experimental animals. It also showed that within the fed restriction NZ group all of the enzymes expression levels were maintained, revealing a greater resistance in the latter breed, over WR, to the under nutrition imposed in the experimental study.