Compensatory growth, plasma hormones and metabolites in juvenile Siberian sturgeon (Acipenser baerii, Brandt 1869) subjected to fasting and re-feeding

A 7-week study was conducted to investigate the effect of different fasting and re-feeding regimes on compensatory growth and some physiological parameters of juvenile Siberian sturgeon (Acipenser baerii). Fish (46.5 +/- 0.5 g) were fed on a diet (containing 450 g/kg crude protein and 20 MJ/kg digestible energy) according to four feeding regimes in triplicate including: control group (C, fed everyday), W1 (2 weeks of feeding followed by 1 week of fasting and 4 weeks of re-feeding), W2 (1 week of feeding followed by 2 weeks of fasting and 4 weeks of re-feeding) and W3 (3 weeks of fasting followed by 4 weeks of re-feeding). The fasted groups including W1 (119.6 +/- 2.1 g), W2 (118.0 +/- 1.7 g) and W3 (108.5 +/- 4.8) significantly lost their weights during fasting phase and did not attain the final weight of the C (137.3 +/- 1.7 g) after re-feeding phase. The re-feeding phase increased the specific growth rate in the fasted groups compared to the C (p < .05). After the fasting phase, concentrations of T-3, T-4, glucose, total protein and triglyceride in plasma of fasted groups were decreased, but levels of total cholesterol, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase increased compared to the C. After re-feeding phase, except for glucose level, all mentioned metabolites were restored in the plasma of W1 group, but total protein level and aspartate aminotransferase concentrations in plasma were not restored in W2 and W3 groups. Overall, our finding demonstrated 4 weeks of re-feeding was too short to induce full compensatory growth in A. baerii juveniles.