Effects of oregano or red pepper essential oil supplementation to diets for broiler chicks with delayed feeding after hatching. 1. Performance and microbial population

This study was conducted to investigate the effects of dietary supplementation of oregano or red pepper essential oil on the performance, digestive organs, serum biochemistry parameters, and microbial population of the small intestine of broilers with immediate, or 24- or 48-h posthatching delayed access to diet and water. The dietary treatments included (1) a non-supplemented corn-soybean meal diet (CONT), (2) CONT + 250 mg/kg of oregano essential oil (OO250), and (3) CONT + 250 mg/kg of red pepper essential oil (RPO250). Irrespective of dietary treatment, especially delayed access to diet and water for 48 h posthatch significantly decreased daily BW gain from 0 to 21 d and daily feed intake from 4 to 21 d and increased the relative weight of the yolk sac at 3 d of broilers. The relative weight of the liver or gizzard of chickens at 21 d was significantly decreased by delayed access to diet and water for 24 h posthatch. The diet containing RPO250 significantly increased the relative weight of the pancreas at 21 d. Delayed access to diet and water for 24 or 48 h posthatch significantly reduced serum glucose levels at 21 d. The serum aspartate aminotransferase level in broilers given immediate access to feed and water was significantly decreased by the diet containing RPO250. Generally, the coliform bacteria and total yeast contents of the small intestine of chickens were significantly increased by extending the time to access to feed and water for broilers. Total aerobic bacteria contents of the small intestine of broilers with immediate, or 24- or 48-h posthatching delayed access to diet and water was significantly decreased by CONT, OO250, and RPO250 diets.