Lactobacillus plantarum and Lactobacillus acidophilus enhance growth performance, immunity, cecal microbiota, and vital organs histomorphology in rabbits.

This study aimed to examine how adding two levels of probiotics, Lactobacillus plantarum and Lactobacillus acidophilus, to the growing V-line rabbits’ basal diet affects growth performance, carcass parameters, hematology, serum biochemistry, digestibility, cecal microbiota, economic evaluation of the diet, and histological and immunohistochemical features of the intestine, kidneys, liver, and heart. Sixty healthy five-week-old male rabbits were allocated at random to three groups, each with four replicates of five rabbits. The standard basal diet was provided to the three groups, with probiotics added to the second and third groups at 0.25 g/kg and 0.50 g/kg, respectively, for the 56-day experimental period. Probiotic supplementation significantly (P < 0.05) improved growth parameters and the weights of internal organs, while reducing the percentage of abdominal fat. White blood cell counts and other hematological parameters increased significantly (P < 0.05). Rabbits supplemented with 0.25 and 0.50 g/kg of probiotics showed significantly (P < 0.05) higher serum total protein, globulin, albumin, T3, T4, IgM, IgG, IgA and levels, and significantly (P < 0.05) lower triglycerides, ALT, and AST levels compared with the control one. Probiotic supplementation increased (P < 0.05) the digestibility of dry matter, organic matter, crude fiber, nitrogen-free extract, crude protein, and ether extract. It positively influenced beneficial cecal microbiota. Histological data showed increased villus length, crypt depth (CD), and epithelial thickness in the intestines. The kidney’s renal corpuscle and glomeruli diameter, along with CMFs diameter, increased. Liver PAS staining showed a dose-dependent increase. TNF-α expression rose significantly in both the small and large intestines, while synaptophysin increased in the large intestine (LI). Therefore, adding probiotics to the rabbit diet could improve performance, hematology, serum biochemistry, nutrient digestibility, cecal microbiota, and the economic evaluation of the diet, as well as the histological features of the intestine, kidneys, liver, and heart.