| To determine the effects of feeding regimes on growth performance and lipid metabolic enzymes in liver of juvenile hybrid tilapia (Oreochromis niloticus×O. aureus),180 fishes with similar body weight (6.80依0.50 g) were randoml divided into 4 groups, including control group (CG, 7 days/week of feeding), group 1 (G1, 6 days/week of feeding), group 2 (G2, 5 days/week of feeding), and group 3 (G3, 4 days/week of feeding). At the end of 56 d experiment, growth performance and the activities and mRNA expression of malic dehydrogenase (MDH) and hormone-sensitive lipase (HSL) in liver were measured. Results showed that, fishes in G1 group got full compensatory growth. There was no significant difference between G1 and CG in final weight, weight gain rate and specific growth rate. Feed efficiency in G1 and G2 significantly increased. With the starvation time prolonging, the moisture and ash content of fish increased significantly, the protein and fat content significantly decreased, MDH activity and mRNA expression in liver of fish significantly decreased, HSL activity and mRNA expression significantly increased. After reefed, the activity and mRNA of MDH, HSL fast recovered, but the values were higher than those in CG. The results indicate that tilapia can improve the feed conversion rate to achieve full compensation growth in 6 days/week of feeding regime. At the same time, in the cycle starvation-refeed regime, tilapia can
change the activity and mRNA expression of lipid metabolism enzymes to reserve energy substances. |
