Effects of a Vitamin-Mineral Premix Containing Probiotic (Pro Max Plus) on Growth Performances and Innate Immune Responses of Nile Tilapia (Oreochromis niloticus)

Developing feed additives capable of enhancing growth performance, fish health, and economic profitability remains a major challenge in intensive aquaculture. This study evaluated the effects of a probiotic-enriched vitamin–mineral premix (Pro Max Plus) on growth performance, feed utilization, innate immune responses, and economic returns in juvenile Nile tilapia (initial mean weight of 42.36 ± 3.95 g). A 60-day feeding trial was conducted using a completely randomized design (CRD) with three dietary treatments: control, a basal diet without supplementation; Pro Max, a basal diet supplemented with a vitamin–mineral premix at 5 g/kg feed; and Pro Max Plus, a basal diet supplemented with a probiotic-containing vitamin–mineral premix at 5 g/kg feed. Fish fed the Pro Max Plus supplementary diet exhibited significantly superior growth performance compared with the other treatments (p < 0.05), achieving the highest weight gain (68.80 g), daily weight gain (1.15 g/day), and specific growth rate (1.85%/day). Feed utilization was also improved, as indicated by the lowest feed conversion ratio (FCR = 0.80) and the highest survival rate (95.55%). Immunological assessments revealed enhanced innate immune responses in fish receiving the probiotic-enriched diet, including increased lysozyme activity, respiratory burst activity, and agglutinating antibody titers. Furthermore, dietary supplementation upregulated the expression of the pro-inflammatory cytokine gene IL-1β while modulating TNF-α expression, suggesting improved immune regulation. Although the probiotic-supplemented diet incurred a slightly higher feed cost, it generated the greatest economic benefit, with the highest benefit–cost ratio (BCR = 1.91) and a profit of 2.19 ± 0.10 THB/fish. These findings demonstrate that supplementation of a vitamin–mineral premix combined with probiotics represents an effective nutritional strategy for improving growth performance, strengthening immune competence, and enhancing economic profitability in commercial Nile tilapia production.