Effect of dietary propolis on growth, body composition, and serum biochemistry of juvenile sea bream (Sparus aurata)

Abstract

This study was conducted to investigate the effect of propolis on the growth, body composition, and serum biochemistry of juvenile sea bream (Sparus aurata). Propolis was added to a commercial sea bream feed (45.51% protein, 17.12 lipid %) at (control) 0 (P0), 1.25 (P1.25), 2.5 (P2.5), 5 (P5), 10 (P10), and 20 (P20) g kg−1. The trial used three replicates of 50 fish (ca 12 g initial weight) in 400-L polyester tanks for each feed treatment, with feeding being done twice daily (09:00 and 17:00) by hand to satiation for 10 weeks. Specific growth rate (SGR) and weight gain (WG) varied quadratically with propolis concentration, with maxima at 3.68 g kg−1. Feed conversion ratio (FCR) and protein efficiency ratio (PER) were not affected by feed treatments (P > 0.05). When body composition was examined at the end of the trial, there were no significant differences between treatment groups in percentage dry matter and lipid, but the highest protein was recorded for group P10 (P < 0.05). Propolis supplementation to the diets showed no effects on glucose (GLU), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in the serum. When the serum biochemical parameters such as total protein (TP), triglyceride (TRIG), and cholesterol (CHOL) were examined, the lowest values were found in the P20 group, while no significant difference was found with the other groups (P > 0.05). The study findings indicated that propolis does not decrease growth rates except at high levels.