The rabbit farming industry is growing due to the rising demand for healthy, sustainable meat. Rabbit meat’s nutritional benefits and low environmental impact appeal to health-conscious consumers. To enhance economic sustainability, efforts focus on reducing disease susceptibility and antibiotic use through improved biosecurity and natural additives, such as organosulphur compounds from Allium plants, which have shown promise in studies for boosting productivity and health. This study aimed to investigate the effects of PTSO supplementation on farm rabbits. Over and after a 76-day period, various parameters were assessed to measure the impacts on rabbit growth, health, biochemical parameters, muscle metabolism, and intestinal microbiota. The rabbit groups received either a control diet or a diet supplemented with Allium extract. The results showed significant improvements in growth performance for rabbits fed with Allium extract, including higher final weights, increased average daily gain (ADG), and lower mortality rates. A biochemical analysis revealed normal values for the parameters measured in the treated group. A muscle analysis evidenced the presence of a few metabolites of PTSO. A gut microbiota analysis indicated distinct differences between the control and treated groups, increasing the presence of some strains that can influence positively the growth of rabbits. This study highlights the potential benefits of PTSO supplementation for improving growth performance, health parameters, and gut microbiota composition in farm rabbits, suggesting its efficacy as a dietary additive.