The Effects of Different Levels of Potassium Diformate and Calcium Diformate on Growth, Digestion Enzyme Activity, Antioxidant Capacity, Intestinal Flora, Stress Markers, and Some Serum Biochemical Analytes in Juvenile Beluga Huso huso

Potassium diformate (KDF) and calcium diformate (CaDF) are organic acids that modulate growth performance, stress, and biochemical status. So, the present study aimed to investigate the effects of different levels of potassium diformate and calcium diformate on growth performance, stress markers, oxidant/antioxidant status, microbial flora, and some serum biochemical analytes in juvenile Beluga (mean weight: 34 ± 4.5 g). Juvenile Beluga fed control food or diet supplemented with different levels of KDF (1, 1.5, and 2 g/kg) and CaDF (1, 1.5, and 2 g/kg) for 60 days. The results showed that fish fed the 0.15% (1.5 g/kg) KDF showed the favorable growth value at 30 days and relatively less, 0.15% CaDF improved significantly (P < 0.05) fish growth performance following 60 days of application (P < 0.05). The results showed that dietary administration of KDF and CaDF significantly (P < 0.05) increased digestive enzymes. Moreover, elevated biochemical parameters were observed in H. huso fed KDF and CaDF supplemented the diet. Serum oxidant/antioxidant status was significantly (P < 0.05) improved in the KDF and CaDF treatments than the control group. Moreover, dietary administration of KDF and CaDF significantly (P < 0.05) decreased stress markers of H. huso after 60 days. The liver enzymes activities considerably altered in the KDF and CaDF groups compared with the control group after 60 days. Furthermore, dietary administration of KDF and CaDF significantly (P < 0.05) increased intestinal lactic acid bacteria (LAB) of H. huso after 60 days. Based on the results of this study, it appears that incorporating KDF and CaDF into the diet of H. huso can have positive effects on their growth performance and physiological response. The study found that a short-term use of 0.15% (1.5) g/kg of KDF for 30 days was the most effective in promoting growth. However, the potential use of 0.2% (2 g/kg) of KDF and 0.15% (1.5 g/kg) of CaDF for a longer period of 60 days may also be beneficial.