Synergistic effects of dietary RISCO-NUTRIFOUR probiotic on broiler performance, upregulation of intestinal immunoglobulin A and mucin-2 genes, enhancement of occludin expression, and downregulation of HSP70 under heat stress

Heat stress (HS) remains a major challenge in poultry production, negatively impacting performance, gut health, and immune function. This study investigated the synergistic effects of a novel probiotic solution, RISCO-NUTRIFOUR (RNFS), on growth performance, immune modulation, and intestinal barrier integrity in heat-stressed broilers. A total of 288 Ross 308 broiler chicks were allocated to six dietary treatments, including RNFS at three inclusion levels [0.4, 0.2, and 0.1% “(4, 2, and 1 L RNFS/ton feed)”], 0.1% Bacillus subtilis , 0.1% Saccharomyces cerevisiae , and a negative control. Over a 42-day trial, RNFS supplementation improved ( p < 0.05) average daily weight gain (ADWG), feed conversion ratio (FCR), and intestinal gene expression of immunoglobulin A (IgA), occludin, and claudin-1, while downregulating the heat shock protein HSP70. These improvements exhibited dose-dependent patterns, with productive performance indices improving at lower RNFS doses, while intestinal gene expression was enhanced at higher inclusion levels. No adverse effects were observed on lymphoid organ development or core metabolic indicators. RNFS also modulated serum lipid profiles favorably and demonstrated a robust antioxidant and immunomodulatory phytochemical profile. These findings highlight RNFS as a promising probiotic feed additive to mitigate HS and enhance gut health and productive performance in broilers.