The Influence of Different Levels of Postbiotic and Phytobiotic Combinations as Feed Additives on Growth Performance, Gut Morphology, and Faecal Bacteria In Broiler Chickens

The current study examined the influence of different levels of postbiotic and phytobiotic combinations on growth performance, gut morphology, and fecal bacteria in broiler chickens. 288 one-day old 308 Ross unsexual broiler chickens were allocated into 6 treatments. Each group had 4 replicates, and each replicate had 12 birds. The treatments included: basal diet without any additive (negative control,NC), basal diet + 0.01% Doxin 200 antibiotic (positive control,PC), basal diet + 0.05 thyme oil + 0.05 postbiotic (0.1% Pos+Phy), basal diet + 0.1 thyme oil + 0.1 postbiotic (0.2% Pos+Phy), basal diet + 0.15 thyme oil + 0.15 postbiotic (0.3% Pos+Phy), and basal diet + 0.2 thyme oil + 0.2 postbiotic (0.4% Pos+Phy). The results showed that broiler chickens fed 0.4% Pos+Phy significantly increased in live body weight and weight gain at 35 days compared to the NC and all other treatments. Also, feed intake increased at different levels compared to the NC and was similar to the PC. The feed conversion ratio was significantly enhanced in birds fed at 0.3% and 0.4% compared to the NC and was not significant within the PC. Generally, the gut morphology at different levels of Pos+Phy was significantly improved. The villi height and width were increased at 0.3% and 0.4% compared to the NC and PC. A higher VH: CD ratio and villus absorptive surface area were found in treatments fed at a level of 0.4%. The faecal lactic acid bacteria count increased at 0.2%, 0.3%, and 0.4% compared to the NC and PC. The Enterobacteriaceae count decreased at  level 0.4% compared to the NC, but no significant differences compared to the PC and all other treatments. The 0.4% Pos+Phy-thyme oil is recommended as a new feed additive and growth promoter as an alternative to antibiotics in broiler.