Effects of dietary probiotics on nutritional quality and aquaculture of Labeo rohita under brackish water rearing system

Probiotics serve as valuable bio-additives in sustainable aquaculture, improving fish growth, health, and antioxidative defenses, and they may also enhance fish production in aquaculture systems. In this study we explored the influence of dietary multi-species probiotics (MSP) on growth performance, body composition, fatty acid profile, stress markers, and intestinal histomorphometry in Labeo rohita reared in a brackish water pond system over a 9-month period. Triplicate ponds of L. rohita (weighed = 20.18 ± 0.22 g initially), with a destiny of 900 individuals per pond, were fed with diets of multi species probiotics (composed of Bacillus subtilis (1.9 ×10 10 CFU/g), Bacillus licheniformis (2 ×10 10 CFU/g), and Clostridium butyricum (2.2 ×10 8 CFU/g) at the rate of 4 % of their body weight per day. The results of this study indicated that MSP diets significantly improved growth performance, digestive enzymes, stress markers, osmoregulatory traits, antioxidant enzymes, crude protein and lipid contents in muscles, when compared to non-probiotics fish (p < 0.05). Moreover, saturated (SFA) and monounsaturated fatty acids (MUFA) showed no significant difference among tested ponds (p > 0.05), however long chain poly unsaturated fatty acids (LC-PUFA) and EPA+DHA enhanced significantly in MSP fed fish across dietary levels (p < 0.05). Intestinal histomorphology and histometric indices improved significantly in brackish water cultured fish across MSP feeding compared to non-probiotics fish (p < 0.05). Findings of this study revealed that dietary multi species probiotics are growth promoters and have significant positive impact on fish productivity, nutritional quality and intestinal health in the brackish water rearing system. This field-scale study offers farmers insight into adopting a sustainable approach for utilizing abandoned brackish water resources to enhance carp production and support economic growth. Graphical Abstract • Dietary MSP were used to enhance L. rohita culturing in brackish water environment. • MSP at 0.5 % and 1 % enhanced L. rohita growth by 22 % and 32 %, respectively, over non supplemented ponds. • Dietary MSP showed potential for improving fish health and antioxidant defense in brackish water. • Probiotics feeding can be an effective nutritional approach to enhance fish production by utilizing brackish water resources.