Effects of different fasting-refeeding regimes on growth performance, hemato-biochemical, and immune indices of juvenile Persian sturgeon (Acipenser persicus Borodin, 1897)

This study evaluated the effects of various fasting–feeding regimes on growth performance, hemato-biochemical, and immune indices of juvenile Persian sturgeon (Acipenser persicus Borodin, 1897). For this purpose, Persian sturgeon juveniles (35.1 ± 5.2 g) were assembled into twelve 100-L tanks (10 fish per tank) and were reared with four fasting-feeding regimes for 40 days in a flow-through system. Four groups were tested: control (fed daily to satiety), T1 (2 days fasting/8 days refeeding, repeated 4 times), T2 (4 days fasting/16 days refeeding, repeated 2 times), and T3 (8 days fasting/32 days refeeding). There were significantly decrease in final weight, weight gain %, specific growth rate, feed intake, and protein efficiency ratio in T2 and T3 treatments (P < 0.05). No significant (P > 0.05) differences were detected in fish survival rate and condition factor among different treatments. Significant declines in key hematological parameters (WBC, RBC, Hb, Hct, MCH, MCV) were observed in T3. Blood glucose and cortisol levels were significantly (P < 0.05) higher; meanwhile serum triglycerides were significantly (P < 0.05) decreased in T2 and T3 groups than those of the Ctrl and T1 groups. Levels of AST and ALT were markedly (P < 0.05) higher in T3 fish than those of the Ctrl and T1 groups with no significant differences between them. Serum total protein and globulin in the Ctrl and T1 were significantly higher than those of T2 and T3. Albumin and cholesterol levels were not significantly (P > 0.05) affected by different fasting-feeding regimes. Compared to the Ctrl and T1 groups, lysozyme, ACH50, and total immunoglobulin levels displayed significant (P < 0.05) decreases in Persian sturgeon subjected to different fasting-feeding regimes and their lowest levels were seen in T3. The economic efficiency analysis evoked that the highest income was seen in the control and T1 groups, which expressed the best benefit-cost ratio, while the T3 treatment showed the lowest income. Overall, juvenile Persian sturgeon subjected to four cycles of 2-day fasting followed by 8-day refeeding (T1) maintained growth, hematological, biochemical, and immune responses comparable to the control group fed to satiety.