Arabic abstract :
This work aims at the identification of relevant intermediate metabolism enzymes contributing to improved meat production
due to genetic selection. A wild rabbit (WR) breed and a highly meat selected breed (New Zealand (NZ) rabbit) were used. Food
restriction was used as an experimental condition so as to enhance differences within the metabolic pathways under study. During
a period of 30 days, NZ and WR experimental breeds were subjected to, respectively, 40% and 60% ad libitum food restriction
leading to 17.7% and 21.1% initial weight. Hepatic glycolytic, lipidic and protein regulatory enzyme activity, transcriptional and
metabolite levels were determined. Insulin-like growth factor (IGF-1), triiodothyronine, and cortisol were also evaluated. In the
glycolytic pathways, the NZ control rabbits presented a higher phosphofructokinase and pyruvate kinase activity level when
compared to the WR, while the latter group showed a higher expression of glycogen synthase, although with less glycogen
content. In the nitrogen metabolism, our results showed a lower activity level of glutamate dehydrogenase in WR when subjected
to food restriction. Within the lipid metabolism, results showed that although WR had a significantly higher mRNA hepatic lipase,
non-esterified fatty acid levels were similar between the experimental groups. NZ rabbits presented a better glycemia control and
greater energy substrate availability leading to enhanced productivities in which triiodothyronine and IGF-1 played a relevant role.
Keywords :
Rabbits , regulatory enzymes , Feed restriction , intermediate metabolism , Enzyme activity
