Effects of Dietary Supplementation of Lactobacillus acidophilus on Blood Parameters and Gut Health of Rabbits

SIMPLE SUMMARY: Gastrointestinal diseases are one of the most common causes of death in rabbits. Thus, maintaining a proper gut health is fundamental to guarantee adequate growth performance and welfare of the animals. Probiotics (e.g., Lactobacillus acidophilus) have been proposed as valuable alternatives to positively modulate gut health. The aim of this study was to evaluate the effects of Lactobacillus acidophilus D2/CSL on biochemical parameters, faecal score, cecal pH, gut histomorphometry, microbiota composition and faecal short-chain fatty acids in rabbits. Overall, the dietary inclusion of 1 × 10(9) cfu/kg feed once a day of Lactobacillus acidophilus D2/CSL did not impair rabbit productive performance, blood biochemical parameters, faecal score, gut morphometry, cecal pH, microbiota and short-chain fatty acids concentration. However, it reduced disease incidence and animal death, suggesting that it could improve disease resistance in rabbits. ABSTRACT: This study aimed to evaluate the effects of Lactobacillus acidophilus D2/CSL (L-1 × 10(9) cfu/kg feed/day) on biochemical parameters, faecal score (FS), cecal pH, gut morphometry, microbiota and cecal short-chain fatty acid (SCFAs) in rabbits. Three zootechnical trials were performed and in each trial 30 rabbits were allotted to two groups; a probiotic group (L) and a control group (C). At slaughter (day 45), samples of blood, duodenum, jejunum, ileum, liver and spleen were collected and submitted to histomorphometric analyses. Blood biochemical analyses, cecal microbiota and SCFAs determination were also performed. In trial 1 and 3, L. acidophilus D2/CSL did not affect productive parameters (p > 0.05). However, L group of trial 1 showed a lower morbidity and mortality compared to the control. In trial 2, C group showed a higher daily feed intake (p = 0.018) and a positive statistical tendency for live weight and average daily gain (p = 0.068). On the contrary, albumin was higher and ALFA-1 globulin was lower in the C group compared to L (p < 0.05). In all the trials, FS, cecal pH, histomorphometry, microbiota and SCFAs were unaffected. In conclusion, L. acidophilus D2/CSL did not impair growth performances, gut and rabbit’s health, reducing morbidity and mortality.