Growth and hematological effects of cellulolytic <i>Bacillus</i> spp. isolated from rabbit gut
Аннотация
Abstract. Turaeva B, Kutlieva GJ, Kamolova XF, Nematofa MA. 2026. Growth and hematological effects of cellulolytic Bacillus spp. isolated from rabbit gut. Biodiversitas 27 (1): d270131. https://doi.org/10.13057/biodiv/d270131. This study aimed to isolate cellulolytic Bacillus strains from the rabbit gastrointestinal tract and evaluate their probiotic potential. Thirteen spore-forming isolates were obtained, of which Bacillus subtilis PBUZ-1 and PBUZ-3 exhibited the strongest cellulolytic activity. Both strains demonstrated high cellulase activity, with PBUZ-1 producing 1.69±0.16 U/mL in whey-based medium compared to 0.29±0.02 U/mL in Getchenson medium (p<0.001, Cohen’s d = 12.49). In vivo trials were conducted on Hikol rabbits supplemented with lyophilized strains (1 × 10⁶ CFU/g feed) for 30 days. Rabbits receiving probiotics showed superior growth performance, with body weights exceeding controls by 312-1050 g at 110-120 days (p<0.01, Cohen’s d = 2.45-3.83). Hematological analysis revealed significant increases in red and white blood cell counts, hemoglobin, and platelets (p<0.05). Biochemical profiles also improved, with higher total protein (65.17±2.24 g/L) and albumin (4.7±0.30 g/L), while bilirubin remained within physiological ranges. No adverse effects were observed, and physiological parameters such as temperature and heart rate stayed within normal limits. These findings demonstrate that rabbit gut-derived Bacillus subtilis strains enhance growth, hematological indices, and systemic health in rabbits. Importantly, this study provides the first evidence that such strains possess dual cellulolytic and probiotic functions, offering a safe and sustainable alternative to synthetic feed additives in rabbit farming and potentially other herbivorous livestock.