Rye and Rye Bran as Components of Diets in Piglet Production-Effects on Salmonella Prevalence

Simple Summary Salmonellosis in humans is still a serious disease, which is mainly caused by the consumption of contaminated food. Functional ingredients in feed are expected to reduce susceptibility to the ubiquitous Salmonella and thus prevent food contamination. Rye is becoming increasingly popular in pig feeding. The use of by-products such as rye bran in pig feeding is also of great interest. Rye and its by-product rye bran offer the possibility of introducing high-quality feedstuffs with positive effects on the pig's intestinal health into a feed. These effects are caused by functional ingredients that are metabolized by microorganisms in the large intestine. Previous studies have shown the positive effect of reducing Salmonella prevalence in young pigs. This study investigated in a field study whether rye or rye bran has a positive effect on Salmonella prevalence in gilts, sows, and piglets. The antibody titers of the rye groups in the gilts were significantly lower. This suggests that the use of rye leads to lower incidents of infection, but this effect was not reflected in the environmental samples. The inconsistent presence of Salmonella and the experimental design were not sufficient to show a clear effect in a field study. The nutritional benefits of rye (and therefore rye bran) are mainly due to its high content of fermentable dietary fiber, the non-starch polysaccharides (NSP). Microorganisms in the large intestine are able to convert these into short-chain fatty acids (SCFA), including butyrate. Butyrate strengthens the epithelial barrier function in the colon by nourishing the enterocytes and inhibiting the spread of Salmonella in the intestinal tract. Therefore, the aim of this study was to test under field conditions whether a diet with rye or rye bran as the main ingredient for gilts, sows, and weaned piglets is associated with a lower Salmonella prevalence. Depending on the age groups, between 20-30% rye or between 15-20% rye bran was used in the experimental group. A total of n = 1983 boot swabs, n = 356 fecal samples, and n = 1909 serum samples were examined. The results of this study show that rye or rye bran at the levels used had no apparent effect on the number of positive Salmonella samples. However, the Salmonella OD values in the experimental groups were significantly lower than in the control group. This suggests that the use of rye leads to a lower incidence of infection, but this effect could not be proven from swabs.

Automated summary

This study investigated the effect of rye and rye bran on the prevalence of Salmonella in gilts, sows, and weaned piglets. The results showed that the use of rye did not have a significant effect on the number of positive Salmonella samples, but the Salmonella OD values in the experimental groups were significantly lower than in the control group.