Raw potato starch diet supplement in weaned pigs could reduce Salmonella Typhimurium infection by altering microbiome composition and improving immune status

Abstract

BackgorundSalmonella enterica serovar Typhimurium (ST) is one of the causative agents of gastroenteritis in pigs. Pigs fed a diet supplemented with raw potato starch (RPS) have improved gut health by the alteration of the microbiota composition and production of short-chain fatty acids (SCFAs). This study aimed to evaluate the effects of RPS supplementation in reducing infection severity and fecal shedding in ST-infected pigs.MethodsThe weaned experimental pigs were divided into two groups: CON (n = 6) fed a corn/soybean-based diet and TRT (n = 6) supplemented with 5% RPS. After 21 d, the pigs were inoculated with ST, and their body weight, clinical signs, and fecal shedding of ST were monitored for 14 d. At 14 d post-inoculation (dpi), the jejunum, cecum, ileum, and colon tissues were collected from euthanized pigs, and histopathological lesions and cytokine gene expression were compared. Additionally, blood samples at 2 dpi were analyzed for gene ontology enrichment. Moreover, the gutmicrobiome was analyzed using 16S rRNA metagenomic sequencing, and the SCFA concentration was measured using gas chromatography.ResultsThe average daily weight gain was significantly higher in TRT than in CON during the ST infection period; however, histopathological lesion scores were significantly lower in TRT than in CON. The relative abundance of nine genera of butyrate- and acetate-producing bacteria significantly increased in TRT compared with that of only two acetate-producing bacteria in CON. Among the genes involved in the immune response, IL-18 expression level was significantly lower in the jejunum and colon in TRT than in CON. Furthermore, Reg3γ expression was significantly different in the cecum and colon of both groups.ConclusionThe diet supplemented with RPS in weaned pigs could result in predominance of butyrate- and acetate-producing bacteria, reducing the severity of ST infection by improving the immune status.

Gut microbiota alteration with growth performance, histopathological lesions, and immune responses in Salmonella Typhimurium-infected weaned piglets

“…Fecal and intestinal tissues were obtained from necropsied pigs at 14 dpi. Bacterial cultures and polymerase chain reaction (PCR) tests were performed as described previously ( Yi et al., 2023 ). The collected tissue samples were preserved in 10 % neutral-buffered formalin and embedded in paraffin wax.…”

“…The collected tissue samples were preserved in 10 % neutral-buffered formalin and embedded in paraffin wax. Sections were prepared and stained according to our previous study ( Yi et al., 2023 ). Histopathological lesions were evaluated using previously established criteria scored on a scale of 0–5, using the following parameters: no lesions = 0; villi shorten = 1; complete villi erosion = 1; presence of Salmonella = 1; high concentration of Salmonella = 1; and inflammatory cells infiltration = 1 ( Argüello et al., 2018 ).…”

“…The expression levels of the three IL genes (IL-10, IL-17A, and IL-18) related to the immune response against Salmonella infection were compared between the two groups. RNA isolation, complementary DNA synthesis, and quantitative RT-PCR were performed according to a previous study ( Yi et al., 2023 ) ( Table 2 ).…”