Effects of supplemental butyrate on gene expression in the intestinal tissues of broiler chickens during Eimeria maxima infection

Coccidiosis is one of the most prevalent gastrointestinal diseases seen in the poultry industry leading to excessive economic losses. Over the last several years poultry producers have begun to look for substitutes to chemotherapeutic agents to meet the demand for chicken raised without antibiotics. The addition of the short chain fatty acid butyrate has been previously reported to mitigate performance loss in chickens during coccidiosis. We hypothesized that addition of tributyrin in the form of glycerol esters of butyric acid can improve performance of Eimeria maxima infected broilers and change the expression of genes associated with gut performance and immune response. Ross 708 male broilers were fed starter diet supplemented with 0 or 0.25% triglycerides of butyric acid (ProPhorce SR 130, Perstorp) from day (d) 1. On d 21, half of the birds were infected via oral gavage with 103 E. maxima oocysts. Experimental groups consisted of birds which were either infected or not infected, consuming normal or supplemented diet (n = 6/group). Tissue samples from the jejunum, ileum, and ceca were collected 7 and 10 d post-infection (PI), and RNA was extracted followed by cDNA synthesis. Relative gene transcription levels for genes related to gut integrity and inflammation were measured by quantitative polymerase chain reaction (qPCR) and normalized to 3 reference genes. Statistical analyses for gene expression were performed using 3-way ANOVA with Holm-Sidak correction for multiple comparisons. At 7 d PI butyrate-supplemented infected chickens showed higher weight gain and lower FCR than those eating normal diet. However, these differences were not significant by 10 d PI. The majority of differences in gene transcription observed were between infected and non-infected samples, and the effect of infection was more prominent at 7 d PI. We conclude that short chain fatty acids may be a promising feed additive for broiler chickens infected with coccidia, but the downstream cellular mechanisms responsible for helping to protect the chicken gut are still unknown.

Key Words: chicken, immune response, nutrition, butyrate, Eimeria.

Abstract presented at the Symposium on Gut Health in Production of Food Animals 2019 in St. Louis, USA.