Impact of Commercial Probiotics on Growth, Prophenoloxidase, Superoxide Dismutase, and Digestive Enzyme Activity in Macrobrachium rosenbergii Cultured at Different Stocking Densities

An experiment using a 4 × 3 factorial design was conducted to evaluate the impact of three commercial probiotics and a control (no probiotic treatment) on the growth, digestive, and immune enzymatic indices of prawns (Macrobrachium rosenbergii) at three stocking densities (2, 4, and 6 m⁻²). The experiment took place in rectangular earthen ponds with a surface area of 120 m² and a water depth of 1.5–2.0 m. The prawns in the treatment groups were fed commercial pelleted feed supplemented with probiotics. The results indicated a significant interaction effect on weight gain (WG), daily weight gain (DWG), daily growth rate (DGR), relative growth rate (RGR), specific growth rate (SGR), and survival. Overall, prawns treated with probiotics showed better growth performance compared to nontreated groups. Prawn cultured with P₁ at a stocking density of 4 m⁻² had better nutritional value, including higher protein level. The activity of prophenoloxidase (proPO), superoxide dismutase (SOD), and lipase enzyme was higher in probiotic-treated groups up to a stocking density of 6 m⁻² compared to control groups (p < 0.001). Probiotic P₁ at stocking densities of 2 and 6 m⁻² showed a significant interaction effect on the protease activity, with other probiotics also enhancing protease activity compared to control. This study highlights that the growth performance, proximate composition, protease, and lipase activity, as well as proPO and SOD activity, of prawns can be improved through the application of probiotic P₁. In conclusion, the study suggests that commercial probiotics enriched with bacterial compositions like P₁ can be effectively used for culture intensification of prawns.