Effects of olive oil and butyl hydroxytoluene (BHT) in diet on digestive and liver enzymes, histology of liver and intestinal tissue of young Persian sturgeon (Acipenser persicus) in brackish water

This study was carried out aimed to determine the effects of olive oil and dietary butyl hydroxytoluene on digestive enzymes, liver enzymes and histology of liver and intestine of Persian sturgeon (Acipenser persicus). 315 pieces of young Persian sturgeon (108 ± 0.02 g) were selected and stored in a completely randomized design with 7 treatments and 3 replications (each replication 15 fish) after adaptation to the Caspian Sea water. Concentrations of 1, 3 and 5% olive oil and 100, 150 and 200 mg/kg of butyl hydroxytoluene and one control treatment were considered. At the end of the period, the levels of digestive and liver enzymes were measured. Liver and intestines of fish were also sampled using biopsy method. The results showed the highest levels of alkaline phosphatase and aminotransferase in treatment 1 and alanine aminotransferase in treatment 2 (p < 0.05). The highest levels of catalase were observed in treatment 3, glutathione peroxidase in treatment 4 and superoxide dismutase in treatment 3 (p < 0.05). The liver and intestinal tissues of fish that used olive oil were in healthy. However, in the liver and intestinal tissues of fish fed a diet containing the antioxidant butyl hydroxytoluene, complications such as bleeding and hyperemia, biliary leakage, cell atrophy, degeneration, tissue necrosis and cell swelling were observed. According to the results, the use of synthetic antioxidant butyl hydroxytoluene in the diet of young Persian sturgeon is not recommended and it is better to replace it with olive oil antioxidant.