Abstract

Background: Probiotics play an important role in improving host animal growth and influence intestinal morphology development. However, this effect varies depending on the type of probiotic used and the form of its administration.
Aim: This study aimed to investigate the effect of probiotics based on native bacterial strains: Enterococcus gallinarum, Exiguobacterium sp., and Lactococcus lactis on the animal growth and intestinal histometry of guinea pigs (Cavia porcellus).
Methods: 72 weaned guinea pigs from a fattening line, with an initial average weight of 248.6 ± 42.2 g, were distributed into six pens. The subjects received oral administration of probiotics as follows: Treatment 1 (T1): Enterococcus gallinarum, Treatment 2 (T2): Exiguobacterium sp., Treatment 3 (T3): Lactococcus lactis, Treatment 4 (T4): a mixture of all three bacteria, Treatment 5 (T5): Zinc bacitracin supplementation, and Treatment 6 (T6): Control. After 63 days, weight gain and feed conversion ratio were determined. Additionally, the villus height and width, depth of crypt of Lieberkühn, and the villus height-to-crypt depth ratio (VH:CD) in the duodenum, jejunum, and ileum were evaluated.
Results: Probiotic application caused differences in weight gain (p = 0.04), specifically between T1 and T3, but did not affect the weekly feed conversion ratio (p = 0.72). On the other hand, intestinal histometry evaluations showed differences in villus height in each intestinal section (p < 0.05). In the jejunum, T4 had a greater villus height than the control (p < 0.05), whereas in the other treatments, probiotics did not increase height compared with the control. Differences were found in villus width in each intestinal section (p < 0.05) but were not greater than the width of the control. Treatments resulted in differences in crypt depth in all sections (p < 0.05), caused by an increase in depth compared with the control. Finally, VH:CD also showed differences throughout the small intestine (p < 0.05), with values similar or lower in probiotics treatments compared with the control.
Conclusions: The application of probiotics based on Enterococcus gallinarum, Exiguobacterium sp., and Lactococcus lactis did not affect the productive parameters of guinea pigs but had an impact on intestinal histomorphology.

Key words: Lieberkühn crypt, duodenum, jejunum, ileum, lactic acid bacteria