Effects of Dietary Taurine on Growth, Body Composition, Blood Parameters, and Enzyme Activities of Juvenile Sterlet (Acipenser ruthenus)

To evaluate the effects of dietary taurine on Acipenser ruthenus, a total of 180 fish with an initial weight of 14.13 & PLUSMN;0.10 g, were stocked into 15 (300 liters) tanks (12 fish/replicate) for 70 days. Five experimental diets (38.60% crude protein and 18.78% crude lipid) supplemented with 0 (T0), 5 (T5), 15 (T15), 30 (T30), and 50 (T50) g/kg taurine were used. The experimental fish were fed to visual satiation four times daily. At the end of the experimental period, weight gain, thermal growth coefficient, and survival in fish fed T30 diet was higher (P < 0.05) than other experimental fish. Food conversion ratio in all treatments containing taurine was significantly lower than T0 treatment (P < 0.05). The highest and the lowest total essential amino acids of muscle were found in T50 and T0 treatments, respectively. The highest serum cholesterol and low-density lipoprotein levels were observed in the T30 treatment (P < 0.05). An increasing trend was observed in the values of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities of serum from T0 to T30 treatments and the highest level was recorded in T30 (P < 0.05). The highest lysozyme, trypsin, chymotrypsin, alkaline phosphatase, lipase, and amylase activities were also observed in T30. Catalase activity in T15 was higher than other treatments (P < 0.05). Malondialdehyde activity in T0 was significantly higher than other experimental treatments (P < 0.05). The highest total numbers of bacteria and lactic acid bacteria of the gut was recorded in T30 and T5, respectively. The overall results indicate that the T30 experimental diet induced the improvement of growth performance, hepatic, digestive, and antioxidant enzyme activities in A. ruthenus.