Response of Piglets to Oral Administration of Lactic Acid Bacteria.

Three experiments were conducted to determine the effects of orally administered Streptococcus faecium M74, Lactobacillus casei spp., Streptococcus thermophilus spp., and Lactobacillus bulgaricus spp. on growth, development of digestive organs, intestinal microflora, and local mucosal immunity of piglets. Mixed-sex piglets were used in the experiments. Bottle feeding of S. faecium M74 plus L. casei spp. increased weight gain in piglets of different litters, but not in piglets of the same litter. The S. thermophilus spp. plus L. bulgaricus spp. cultures improved only weight gain for 12 to 21 days of age. There was no significant effect of lactic acid bacteria (LAB) administration on plasma glucose, urea, calcium, alkaline phosphatase, total proteins, albumin, and globulins. The number of lactobacilli was higher and the enterococci and coliforms lower in the groups fed LAB than in the control group. The ratio of lactobacilli to coliforms increased in the intestinal contents of the LAB groups. The pH values of the gut contents were not affected by treatments. Although a significant effect on the size of the digestive organs was not found, the liver weight was smaller and the intestinal length shorter in the treated than in the control group. There were no significant differences in the level of interleukin-2 in the tissues of the jejunum and ileum. However, in the group given S. faecium M74 plus L. casei spp. the interleukin-2 concentration in the ileal tissues increased from 3.74 (control) to 7.43 ng/g. The histological structure of the ileal epithelium of the group of piglets given S .faecium M74 plus L. casei spp., showed an increase in the phagocytic activity of the cells. Some differences in the endoplasmic reticulum and mitochondria in the location of the implanted microvilli were observed in the group given S. thermophilus spp. plus L. bulgaricus spp.