Growth, physiological, antioxidants, and immune response of heteroclarias catfish fingerlings, to dietary Moringa oleifera leaves extract and its susceptibility to Aeromonas hydrophila infection
Moringa oleifera leaves are an important phytobiotic agent due to their growth-promoting, anti-inflammatory, hepatoprotective, antimicrobial, and antioxidant properties. Thus, it has become a spicy and disease-control agent in traditional medicine. In this study, Moringa oleifera leaf extract (MOLE) was fed to hybrid catfish (Heteroclarias, Clarias gariepinus ♀ × Heterobranchus longifilis ♂) to evaluate its effects on growth, hematological parameters, liver enzyme activity, antioxidant capacity, immunity and susceptibility to Aeromonas hydrophila infection. Fish (n = 300 fish, mean weight 9.3 ± 0.2 g) were fed diets supplemented with 0.0, 0.5, 1.0, 1.5, or 2.0 g MOLE/kg diet for 56 days. Thereafter, fish were challenged with molecularly characterized A. hydrophila (ATCC 4356; 5.0 × 105 CFU/mL) infection for 14 days. Growth performance and feed intake of heteroclarias were significantly (p < 0.05) promoted with an increase in MOLE levels with an optimum of 1.25 g MOLE/kg. It was noticed that final body weight, specific growth rate, and feed intake were increased with an increase in MOLE levels, and they are highly correlated. More so, dietary MOLE significantly evoked (p < 0.05) hematological profiles and antioxidant profiles of heteroclarias than the control group. Alanine aminotransferase was significantly reduced in fish fed MOLE-based diets compared to the fish fed a control diet, with their least value (27.27 IU/L) observed in fish fed a diet with 1.5 g MOLE/kg, while the highest was recorded in fish fed a control diet (32.03 IU/L). Also, non-specific immune profiles were greatly promoted by dietary supplementation. Additionally, fish survival post A. hydrophila infection was higher in fish fed a 2.0 g MOLE/kg diet (96.33%) than those fed a control diet (46.67%). This study revealed that MOLE administration enhanced the growth performance (linearly and quadratically), antioxidant (linearly), and innate immunity (linearly and quadratically) profiles of heteroclarias with an optimum level of 1.35 g/kg of diet. Likewise, its addition to the diets evoked the survival of fish against A. hydrophila infection.