Serum biochemical profile and performance of broiler chickens fed diets containing essential oils and pepper

Serum biochemical parameters and performance data were evaluated in broilers fed diets supplemented with antibiotics or essential oils from oregano, sage, rosemary, and pepper crude extract (OLES). Animals (n = 910) were distributed into five treatment groups, with seven replicates of 26 birds in each group: the control group (diet without additives); the group receiving an antibiotic growth promoter diet; and the groups T₅₀, T₁₀₀, and T₁₅₀ (feed supplemented with 50, 100, and 150 mg/kg of OLES, respectively). After 42 days, 55 animals were randomly selected for serum biochemical profile analysis involving pancreatic, renal, and hepatic functions (lipase, amylase, urea, uric acid, aspartate aminotransferase, gamma glutamyltransferase, total cholesterol, high-density lipoprotein, triglycerides, total protein, albumin, globulins, and albumin/globulins ratio). Growth performance of broilers (body weight, weight gain, feed intake, alimentary conversion, and mortality) was also evaluated throughout the experiment period. The increase in serum levels of lipase, uric acid, urea, and aspartate aminotransferase suggests that OLES may cause kidney and liver impairment, mainly, at the higher dose. The OLES dose of 100 mg/kg is suitable for a final body weight and a weight gain similar to those observed in broilers supplemented with antibiotic growth promoters.