Supplementary Prebiotics, Probiotics, and Thyme (Thymus vulgaris) Essential Oil for Broilers: Performance, Intestinal Morphology, and Fecal Nutrient Composition

This experiment was performed to evaluate the effects of selected natural feed additives (thyme extract, organic acid, probiotic, and prebiotic) on performance, intestinal morphology, and composition of fecal nutrients with two crude protein levels diet (10% reduced crude protein level and the recommended level) in broilers. In this experiment, 388 Ross-308 strain broilers from 1 to 42 days in three experimental periods including starter (1 to 10 days), grower (11 to 24 days), and finisher (25 to 42 days) were used in a completely randomized design (8 treatments, 4 replicates, and 12 chickens in 5 × 2 factorial arrangements). According to the results, use of feed additives along with both levels of crude protein had significant effects on performance, intestinal morphology, and fecal nutrient levels ( P 0.05). Lower crude protein level changed the intestinal morphology ( P