Dietary probiotic supplementation with <i>Lactococcus lactis</i> and <i>Bacillus velezensis</i> enhances growth performance, meat quality, blood profiles, and cecal and feed microbiota in growing rabbits

This study explored the effects of dietary supplementation with a probiotic blend of <i>Lactococcus lactis</i> subsp. <i>lactis</i> and <i>Bacillus velezensis</i> on the performance and health of growing rabbits. Ninety-six rabbits were allocated into three groups and fed for eight weeks on diets containing either no probiotic (control), a low-dose probiotic (1 ml/kg of each probiotic strain), or a high-dose probiotic (2 ml/kg of each probiotic strain). Probiotic inclusion, particularly at the higher level, significantly enhanced final body weight, feed conversion ratio, and overall performance. Improvements were also noted in carcass characteristics, with greater yields in both forequarters and hindquarters. Blood biochemical analysis revealed elevated antioxidant enzyme activity and immunoglobulin levels, alongside reductions in lipid fractions and better liver and kidney function indicators. Meat quality also benefited, as shown by lower pH, reduced water holding capacity and cooking loss, and more favorable color metrics. Microbial analysis of cecal and feed samples indicated a notable increase in beneficial bacteria and a decline in pathogenic species in the probiotic-treated groups. These findings suggest that combined probiotic supplementation is a promising strategy for enhancing growth performance, meat quality, and gut health in rabbit production systems to produce a good final meat product.