Fermented Feed to Improve the Performance and Immunity of Indigenous Chickens under Free-Range Rearing

The purpose of this study was to evaluate the use of fermented feed on the growth performance and immunity of Thai indigenous chicken rearing under free-ranging.Sixty 35-day-old Thai indigenous chickens (Pradu hangdum) were divided into three groups with four replicates on five birds: a control group receiving a dry diet, and two experimental groups receiving 25% and 50% fermented feed, respectively.The fermented feed was prepared by adding 1% Thua-nao to a basal diet, then filling tap water at a ratio of 1:1.5 and incubating at 37 for 24 hours.The chickens were raised in a free-range system until they reached 98 days of age.It was found that the feed conversion ratio of chickens fed fermented feed was better than the control group (P<0.05).The AST was decreased in chickens fed fermented feed (P<0.05).The serum IgY of chickens fed 50% fermented feed was the highest, while serum IgM was not significantly different among the group.The staining intensity of IgA using 3,3'-diaminobenzidine was highest in chickens fed 50% fermented feed (P<0.05).The defeathered and eviscerated carcasses of chickens fed fermented feed showed higher values than the control (P<0.05), while most of the gastrointestinal organ weights of chickens fed fermented feed were lower than the control (P<0.05).Therefore, feeding 25-50% fermented feed enhances the growth performance and immunity of Thai indigenous chickens under free-range rearing.