|HANSEN, VICTORIA - US Department Of Agriculture (USDA)|
|Kahl, Stanislaw - Stass|
|JIMÉNEZ, STEPHANIE - US Department Of Agriculture (USDA)|
|VAESSEN, STEFAN - Perstorp Waspik Bv|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2021
Publication Date: 1/18/2021
Citation: Hansen, V.L., Kahl, S., Proszkowiec-Wegla, M.K., Jiménez, S.C., Vaessen, S., Schreier, L.L., Jenkins, M.C., Russell, B.A., Miska, K.B. 2021. The effects of tributyrin supplementation on weight gain and intestinal gene expression in broiler chickens during Eimeria maxima-induced coccidiosis. Poultry Science. https://doi.org/10.1016/j.psj.2021.01.007.
Interpretive Summary: Both food regulations and consumer preferences are increasing the demand for antibiotic-free chicken. Unfortunately, even with excellent farm hygiene, outbreaks infections happen on poultry farms. Coccidiosis is caused by a parasite called Eimeria that causes diarrhea and intestinal lesions, causing loss of weight gain as well as potentially fatal secondary infections. Industrial broiler chickens today typically grow from hatch to market weight in 4-6 weeks so even mild coccidiosis outbreaks can lead to significant economic losses. Here we examined the effectiveness of an antibiotic-alternative feed supplement, butyrate, that has shown promise as a means to help livestock maintain weight gain. Butyrate is a compound that is also made naturally by healthy gut bacteria. We specifically tested a product called ProPhorce SR 130 (Perstorp), which has a palatable buttery smell and is absorbed through the intestine. We examined the effects of tributyrin supplementation on body weight gain (BWG), feed conversion ratio (FCR), feed intake (FI), and gene expression in the intestine during infection with Eimeria maxima. E. maxima was chosen because it is one of the most common Eimeria species that causes coccidiosis outbreaks in poultry farms across the world. In this study we compared chickens fed supplemented or normal feed that were also either infected with E. maxima or sham-inoculated. Animals were sacrificed at either 7 days post-infection (7 d PI), when diarrhea and morbidity is high, or at 10 days post-infection (10 d PI), when coccidiosis is being cleared up by the immune system. We found that tributyrin supplementation had a significant positive effect on BWG and FCR during E. maxima infection at 7 d PI. We also examined gene expression in the intestine for genes involved in immune regulation, nutrient absorptions, and gut integrity. We observed that butyrate supplementation did not have significant effects on most of the genes we tested, regardless of infection status. Gene expression was impacted more on 7 d PI than 10 d PI for groups infected with E. maxima. Interestingly the sampling day (7 or 10) also had an effect on some gene expression and may be attributed to the study animals still growing and developing on their way to adulthood. Overall, we found that tributyrin has promise as a broiler chicken feed additive to alleviate some of the effects of E. maxima infection.
Technical Abstract: Butyrate is a feed additive that has been shown to have anti-bacterial properties and improve gut health in healthy broilers. Here we examined the performance and gene expression changes in the ileum of tributyrin supplemented broilers infected with coccidia. Ross 708 broilers were fed either a control corn-soybean based diet (-BE), or a diet supplemented with 0.25% (w/w) tributyrin (+BE). Birds were further divided into groups that were inoculated with Eimeria maxima oocysts (EM) or sham-inoculated (C) on day 21 post-hatch. At 7 days post-infection (7 d PI), the peak of pathology in E. maxima infection, tributyrin-supplemented birds had significantly improved feed conversion ratios (FCR, P<0.05) and body weight gain (BWG, P<0.05) compared to -BE infected birds, despite both groups having similar feed intake (FI, P>0.05). however at ten days post infection (10 d PI) significant effects of feed type or infection were not observed. Gene expression in the ileum was examined for insights into possible effects of infection and tributyrin supplementation on genes encoding proteins related to immunity, digestion, and gut barrier integrity. The immune related genes examined (IL-1B and LEAP2) were only significantly affected at 7 d PI. Transcription of genes related to digestion (APN, MCT1, FABP2, and MUC2) were primarily influenced by infection at 7 d PI and occasionally (FABP2, and MUC2) tributyrin supplementation at 10 d PI. With exception of ZO1, tight junction genes were affected by either infection and feed type at 7 d PI. At 10 d PI only CLDN1 was not affected by either infection or feed type. Overall tributyrin shows promise as a supplement to improve performance during coccidiosis in broiler chickens, however its effect on gene expression and mode of action remains unclear.