The effects of different levels of postbiotic and phytobiotic combination as feed additives on carcass, lipid profile, meat quality, and tibia bone in broiler chickens

Like probiotics, postbiotics function without the presence of living cells and are composed of bacteriocins and metabolites that are antibacterial. They improve chicken products and health by reducing acidity in the gut and preventing infectious diseases. A total of 288 one-day-old unsexed broiler birds (Ross308) were divided into sex-specific treatment groups, with each group having four replicates and each replicate containing twelve birds.The treatment groups were as follows: T1 = Standard diet (negative control), T2 = Standard diet + 0.01% doxin200 (positive control), T3 (0.1%) = Standard diet + 0.05% thyme oil + 0.05% postbiotic, T4(0.2%) = Standard diet + 0.1% thyme oil + 0.1% postbiotic, T5(0.3%) = Standard diet + 0.15% thyme oil + 0.15% postbiotic, T6 (0.4%) = Standard diet + 0.2% thyme oil + 0.2% postbiotic. The results showed significantly (P<0.05) increased breast cuts and a decrease in back cuts, in birds given varied levels of combined postbiotic and phytobiotic (0.1%, 0.2%, 0.3%, and 0.4%) compared to the negative and positive controls. Serum levels of total cholesterol and triglycerides showed significant reductions, and there was an increase in HDL among all groups of birds that received different levels of dietary supplements, as compared to the positive and negative control. The meat cooking loss rate was significantly reduced in birds fed at a 0.4% level compared to all experimental groups. No significant differences (P > 0.05) in meat color were noticed by feed additives compared to the positive control and stayed within the normal range. Various levels of the combination diet significantly improved tibia bone health, especially at a level of 0.4% (T6). In conclusions, a level of 0.4% combined (0.2% postbiotics+ 0.2% phytobiotics(thyme oil) as viable alternatives to antibiotics in broiler diets.