Effect of Oat Hulls Incorporated in the Diet or Fed as Free Choice on Growth Performance, Carcass Yield, Gut Morphology and Digesta Short Chain Fatty Acids of Broiler Chickens

The use of high fiber agricultural byproducts in poultry nutrition can help not only to reduce feed cost but also to promote gastrointestinal functionality and growth performance and enhance environmental sustainability. This study was conducted to examine the effect of oat hulls (OH) incorporated in the diet or fed as free choice on growth performance, intestinal morphology, cecal short chain fatty acids (SCFA) production and carcass yield of broiler chickens. Day old broiler chickens were assigned to 4 dietary treatment groups which consisted of a corn-soybean meal-wheat based diet (Basal), Basal + bacitracin methylene disalicylate (BMD), Basal + 3% OH (3% OH) and Basal + free choice OH (FCOH). Each group had six replicate pens of 27 chicks and were raised for 39 d. Feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) were determined weekly for each pen. One chicken/pen was slaughtered on d 36 to determine organ weights, jejunal morphology, digesta pH and cecal SCFA and two chickens/pen were slaughtered on d 39 to determine carcass weight and yield. Diet had no effect on FI, except on d 28, when the FCOH group had higher FI than the 3% OH groups. During the starter phase, chickens fed 3% OH had the highest BWG and lowest FCR, which were significantly different (p < 0.05) from those fed FCOH. Chickens fed 3% OH had the highest slaughter, hot carcass, and cold carcass weights, which were significantly different (p < 0.05) from those fed FCOH. Diet had no effect on jejunal villus height and crypt depth, ileal and cecal digesta pH, and cecal SCFA. Chickens fed FCOH had a larger (p < 0.0001) gizzard weight and showed a tendency to have a larger (p = 0.09) ceca weight than other treatment groups. In conclusion, the inclusion of 3% OH in an antibiotic-free diet has the potential to enhance growth performance, while free choice OH increases the gizzard weight of broiler chickens.