The research assessed the efficacy of a bacterial supplement containing six strains of the genus Lactobacillus in a feeding trial conducted in recently weaned pigs.
Results of their study, reported in the journal Livestock Science, found that while the strains tested did not boost growth, and may have faced difficulties colonizing the intestinal tract, they did alter the expression of some intestinal cytokines in the young animals.
“While the lactobacilli supplement used in this study failed to achieve a growth-enhancing effect, and the supplemented strains appeared to have a limited ability to compete with the indigenous intestinal microbiota of piglets, the supplement evoked immunomodulatory properties in the piglet intestine,” said the researchers.
Why supplemental Lactobacillus
Lactobacilli are considered a necessary part of the microbiota within a pig’s intestinal tract. However, the amount present tends to drop when piglets are weaned, said the scientists.
“This has been considered to predispose piglets to gut disturbances, [such as] diarrhea,” they said. “Therefore, dietary supplementation with lactobacilli may help in maintaining better host health around weaning,” added the animal nutrition experts.
Study details
The team said the objective of the study was to evaluate the effect of this multispecies lactobacilli supplementation on the performance and intestinal cytokine expression of piglets, as well as to monitor the survivability of the strains within the intestine.
In the experiment, 20 piglets were split into two groups, one of which received a probiotic supplement containing six strains of Lactobacillus for three weeks. Both sets of piglets also were given a commercial creep feed including 37% barley, 22% oats, 20% wheat, 6% fishmeal, 3% whey powder and 3% soy protein.
Piglet health and fecal matter were monitored on a daily basis and feces samples and weight data were collected at points in the trial, researchers said. Sections from the small and large intestine were gathered at the end of the time period. Additionally, the pH of the luminal content was analysed and samples of intestinal digesta were taken from the jejunum, ileum, cecum and spiral colon.
Results
The body weight at weaning and average daily weight gain were recorded and calculated, but no statistically significant differences were found between pigs that received the supplement and those that didn’t, said the team. Additionally, there was no statistically significant difference in the pH of the intestinal lumen between the two groups.
Examination of the fecal samples found that the probiotic strains were present in the manure of both sets of pigs but “none of the isolates from the supplementation group were identical to the genotypes of the strains that had been supplied,” researchers reported.
The total amount of bacteria in the digesta samples was also evaluated and there was a statistically larger amount of overall bacteria in the jejunum of the pigs that received the supplement, though bacteria counts other places were the same. There also was little difference in the amount of lactobacilli intestinally present in either group.
Several cytokines were “upregulated” in parts of the cecum for pigs in the group getting the probiotic supplement though others were “downregulated,” in the colon, jejunum and ileum, researchers said.
“The lactobacilli supplementation also showed immunomodulatory effects in the intestinal mucosa of the piglets, with these effects being localized mainly in the large intestine,” they added.
Strain details and experiment considerations
The different strains used in the experiment were selected for in vitro probiotic characteristics, said researchers.
Previously, the strains had been linked to “antimicrobial activity towards intestinal pathogens, adhesion to porcine enterocytes isolated from small and large intestine, and tolerance to low pH and bile.”
Although the strains used did not achieve growth promotion for pigs in the study, using the specific probiotic in a laboratory setting may have skewed the results, the authors noted.
Or there may be other factors that play into growth promotion like specific strains or when use starts and how long it is given.
“Increased resistance against gastrointestinal infections might be one of the mechanisms behind the growth enhancing effect of probiotics in animals,” they said. “Therefore, the lack of growth promotion is not necessarily an unexpected outcome in feeding trials like ours, executed in special animal facilities with a good level of hygiene, where the housed animals are presumably subjected to a lower environmental bacterial load in comparison with those in commercial intensive rearing units.”
The total amount of lactobacilli present did not appear altered by the supplement, but there may have been some alterations within the “lactobacilli community structure,” researchers said.
“Indeed, the increased level of total bacteria observed in the jejunum digesta of the supplementation group suggests that there were some changes in the indigenous microbiota, at least in this intestinal compartment, but a more detailed analysis of the microbial community composition would be needed to clarify any possible alterations evoked by the supplementation,” they said.
What’s next?
More work will need to be done to better understand the influence that the supplements have on cytokine gene expression, researchers said, and on the role that specific cytokines play.
Additionally, more research could be done to better explicate the “health consequences” of the immunological changes produced by the probiotic supplement.
Source: Livestock Science
Title: Effect of a multispecies lactobacillus formulation as a feeding supplement on the performance and immune function of piglets
Doi: 10.1016/j.livsci.2015.07.016 published online before print
Authors: Tanja Lähteinen, Teemu Rinttilä, Joanna Koort, Ravi Kant, Katri Levonen, Miia Jakava-Viljanen, Johanna Björkroth, Airi Palva,