Effects of Dietary Different Levels of Thyme Essential Oils on Growth Performance,Nutrients Utilization,Serum Biochemical Parameters and Intestinal Flora of Broilers

To study the effects of dietary different levels of thyme essential oils on growth performance,nutrients utilization,serum biochemical parameters and intestinal flora of broilers,7681-day-age Mahua chicken were allotted into 8 treatments which contained 4 replicates and 24 birds per replicate.The basic diet was added with 0.00,0.05,0.10,0.15,0.20,0.25,0.30 and 0.35 mg/kg thyme essential oil.Metabolic tests were carried out during 17 to 21 and 38 to 42 days of age to determine nutrient availability.Four birds were selected from each replicate and killed on day 21 and day 42.The results showed that thyme essential oil could significantly improve ADG and reduced F/G at 22 to 42 and 1 to 42 days of age.At the same time 0.05,0.1,0.15,0.2 mg/kg essential oils significantly decreased duodenal,ileal Escherichia coli,Salmonella and Lactobacillus amount;0.15 mg/kg essential oils significantly improved serum total protein of 1 to 21 days age and serum calciam of 22 to 42 days age(P0.05);0.1 mg/kg essential oils significantly improved crude protein,metabolizable energy of 1 to 21 days age,phosphorus nutrient apparent utilization of 22 to 42 days age(P0.05).According to all the parameters,it was suggested that the essential oils add a level of 0.1~0.25 mg/kg were superior.