Abstract
Butyrate is a short-chain fatty acid that can be given as a dietary additive to support intestinal health and poultry performance. Providing butyrate in a protected form that reaches the hindgut could have different effects than an earlier-absorbed butyric acid salt. To compare these additives, 468 broiler chicks were housed 12 birds per pen, with 13 pens per dietary treatment. Birds were fed a three-phase feeding regimen for 42 d divided into three dietary treatments: a negative control diet, a diet containing 260 mg of unprotected sodium butyrate/kg diet, or a diet containing 260 mg/kg diet of a fat matric encapsulated calcium butyrate. Performance parameters (daily gain, daily feed, and gain to feed ratio) were obtained for the overall feeding study. On d 42, samples of cecal fluid were collected for pH and volatile fatty acid (VFA) analysis (n = 13 pooled samples/diet), jejunum and colon tissue for intestinal morphology evaluation (n = 6 birds/diet), cecum, cecal tonsil, crop, and spleen tissues for quantitative PCR evaluation (n = 8 birds/diet), and jejunum and colon for ex vivo assessment of intestinal integrity and barrier function (n = 13 birds/diet). There was no effect of dietary treatment on feed intake or feed efficiency (P > 0.10) with a tendency for gain to increase due to dietary butyrate, regardless of source (P = 0.07). There was no effect of dietary butyrate on cecal pH, propionate, butyrate, or total VFA (P > 0.10) with a tendency for butyrate, regardless of source, to reduce acetate concentrations (P = 0.07). There was no effect of dietary butyrate on intestinal morphology (P > 0.10) or barrier functions (P > 0.10) in the jejunum or colon. Diets containing the protected-calcium butyrate generally decreased gene expression of tight junction and inflammatory genes in the cecum and decreased inflammatory gene expression in the cecal tonsil and spleen. In general, dietary butyrate, regardless of source, exhibited little effect on performance or most physiological measures.