Effects of a multi-strain probiotic on rabbits productive traits, antioxidant defence, caecal microbiota and short‑chain fatty acids, and intestinal histomorphology.

Objective: This paper aimed to evaluate the effects of a multi-strain probiotic as natural feed additives on the productive performance, blood parameters, antioxidant defence, caecal short‑chain fatty acid profile as well as the effectiveness on the intestinal morphology and on the equilibrium modification of caecal microbiota of growing rabbits.

Methods: Eighty-six-week-old Italian White rabbits were assigned into two dietary groups: the control group was fed without any additive, while the test group received a diet supplemented with a multi-strain probiotic (MS-Prob; Slab51®) at a dosage of 250 mg/kg diet. The feeding trial lasted up to 12 weeks of age.

Results: Rabbits MS-Prob diet had significantly higher daily and final body weight recording also the best of feed efficiency compared to control group. Rabbits in MS-Prob group showed improved slaughter weight and carcass dressing yield. No significant effect was found on meat protein, lipids and ash contents. Serum total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglycerides decreased significantly in rabbits fed the test-diet. In rabbits fed MS-Prob, the activity of glutathione peroxidase (GPx), glutathione S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) increased significantly, whereas the level of thiobarbituric acid-reactive substance (TBARS) decreased significantly. Caecal pH, ammonia-N and total volatile fatty acids (VFAs) were not significantly influenced by dietary treatments. Conversely, VFAs molar proportions were statistically affected by diets, with higher acetic and butyric acid concentrations in caecum of rabbits fed MS-Prob. Feeding of MS-Prob reduced harmful bacterial growth (Escherichia coli, Bacillus spp., Clostridium spp.) while promoting beneficial bacteria (Lactobacillus spp., Bacteroides spp.). Moreover, MS-Prob positively influences rabbit gut histomorphology, showing higher villus height, villus width, and crypt depth.

Conclusion: s: This study indicated that MS-Prob (Slab51®) supplementation stimulated the performance of growing rabbits and positively affected blood serum parameters, intestinal morphology, and caecal environment and microbiota.