Efficacy of dietary thiamine supplementation on growth performance, digestive enzymes, immunological responses, and antioxidant capacity of juvenile beluga (Huso huso)

Abstract

The aim of the current study was to investigate the beneficial effects of dietary thiamine supplementation on physiological, immunological and antioxidant responses in juvenile beluga, Huso huso. The juvenile fish (∼ 3 g) were fed four times a day with diets containing 0 (control), 5 (5 T), 10 (10 T), and 20 (20 T) mg kg−1 thiamine for 12 weeks. Significant increases were observed in growth performance indicators of the fish fed different levels of thiamine, compared to the control group and the best performance was observed in 10 T treatment. The carcass protein content significantly increased in the thiamine-treated fish and the highest protein content was observed in the 10 T treatment. Digestive enzymes’ activities (pepsin, trypsin, lipase, and amylase) significantly increased in the fish fed the thiamine-supplemented diets. The serum alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities significantly decreased in the 10 T and 20 T treatments, compared to the control group. Dietary thiamine supplementation significantly increased the serum lysozyme, alternative complement activities, and IgM level, compared to the control diet and the highest lysozyme activity and IgM level were observed in the 10 T and 20 T treatments. The hepatic superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-s-transferase, transketolase activities of 10 T and 20 T treatments were significantly higher than those of the control treatment. The hepatic catalase activities in the thiamine-treated fish were significantly higher than that of the control fish. Contrastingly, the hepatic malondialdehyde contents of the 5 T, 10 T, and 20 T treatments were significantly lower than the control treatment. Although all the dietary thiamine levels (5–20 mg kg−1) showed beneficial effects on different tested parameters, 10 mg kg−1 was the most beneficial level and is recommended for dietary inclusion to improve the growth and health of juvenile beluga.