Abstract
In recent years, scientific interest in functional ingredients capable of replacing the non-therapeutic use of antibiotics in animal feed has intensified, fostering the exploration of novel additives such as Saccharomyces cerevisiae hydrolysate (SCH). This study investigated the effect of dietary SCH supplementation on growth performance, intestinal morphology, local immune response, and cecal microbiota composition in Ross 308 broiler chickens. A total of 300 one-day-old male chicks were randomly assigned to two experimental groups, receiving either a standard diet or a diet supplemented with SCH (500 mg/kg during the starter and grower phases; 250 mg/kg during the finisher phase). SCH supplementation significantly improved growth performance during the finisher phase, with increases in final body weight (p = 0.025), average daily gain (p = 0.049), and average daily feed intake (p = 0.027), without significant changes in feed conversion ratio (p > 0.05). Favourable intestinal morphological modifications were observed, with a significant increase in villus height to crypt depth ratio in both the jejunum and ileum at days 28 (p = 0.035 and 0.002, respectively) and 42 (p < 0.001). The expression of pro-inflammatory cytokine genes was significantly reduced, with lower levels of TNF-α, IL-1β, and IL-6, while tight junction protein genes ZO-1 and Occludin were significantly upregulated (p < 0.05). Microbiota profiling revealed higher alpha diversity and greater abundance of Prevotella. These findings highlight SCH as a promising dietary strategy to improve broiler performance, intestinal function, and sustainability in poultry production systems.