The Effects of starvation and refeeding on growth and digestive enzymes activity in Caspian brown trout (Salmo caspius Kessler, 1877) fingerlings

240 Caspian brown trout (Salmo caspius) fingerlings with initial weight of 13.74±0.63 g were stored in 300 L tanks to investigate the effect of starvation and refeeding on compensatory growth and digestive enzymes activity. The fish were introduced to four different periods of starvation during 10 weeks including control (with no starvation: C), 2 weeks (S2), 4 weeks (S4) and 6 weeks (S6) and then fed to satiation during the refeeding period. Sampling for growth and enzymes activity measurements was conducted three times: day 1 (T1), after starvation (T2), after 2 weeks (R2) and 4 weeks (R4) of refeeding. Results have indicated a significant decrease in growth performance after starvation (p<0.05). Final weight (W2) was similar to the control group in treatment of S2 after 2 weeks of refeeding. Body weight increasing (BWI) and specific growth rate (SGR) were the highest in treatment of S6 at the end of trial (p<0.05). Trypsin, chymotrypsin, lipase and amino peptidase declined after starvation while pepsin activity significantly increased in deprived fish (p<0.05). Trypsin and chymotrypsin values were lower in S6 than of control whereas the lowest activity of pepsin was observed in the control fish. After 4 weeks of refeeding, trypsin and chymotrypsin values were similar to that of the control (p>0.05). Generally, results declared that Caspian brown trout fingerlings could recover digestive capacity after 2 weeks of starvation by appropriate refeeding with no negative impact on growth performance.