Dietary Aloe vera supplementation enhances stress resilience and physiological recovery in transported Labeo rohita fingerlings: optimizing growth, immunity, and feeding behavior

This study investigated the effects of dietary Aloe vera supplementation on stress mitigation and recovery in transported Labeo rohita fingerlings using a completely randomized design with four treatment groups (0%, 0.5%, 1.0%, and 2.0% Aloe vera supplementation) and three replicates per treatment. Fish (initial weight, 5.8 ± 0.2 g) were fed experimental diets for 3 weeks prior to undergoing a standardized 4-h transportation stress protocol in oxygen-filled polyethylene bags. Post-transport, fish were returned to their respective tanks and maintained on the same experimental diets for an additional three weeks to evaluate recovery. Fish were sampled at weekly intervals (pre-transport days 7, 14, and 21; post-transport days 7, 14, and 21) to assess growth, physiological parameters, immune function, and feeding behavior. The 1% supplementation level showed optimal results, with significantly higher survival (98.3 ± 0.7%), weight gain (47.6 ± 2.1% during post-transport period), and improved feed conversion ratio (1.45 ± 0.06) compared to other treatments (p < 0.05). Post-transport cortisol levels were significantly lower in the 1% group (15.8 ± 1.2 ng/L) by week 3 compared to controls (35.4 ± 1.7 ng/L). Immunological analysis revealed significant enhancement in the 1% treatment group, with higher lysozyme activity (148.6 ± 4.2 U/mL), respiratory burst activity (0.89 ± 0.04 OD540nm), and total antioxidant capacity compared to controls. Feeding behavior also improved significantly, with shorter feeding latency (12.4 ± 1.2 s) and higher feed intake (2.8 ± 0.1% body weight/day) in the 1% treatment group. Water quality parameters were maintained within optimal ranges throughout the experiment with regular water exchange. Results demonstrate that 1% dietary Aloe vera supplementation effectively mitigates transport stress and enhances physiological recovery in L. rohita fingerlings, offering a sustainable approach to stress management in aquaculture.