The effect of Propionic acid on growth performance, digestive enzyme activities and blood parameters of common carp (Cyprinus carpio)

The effects of formic acid on growth performance, blood indices, and digestive enzyme activities of common carp (Cyprinus carpio) were examined over 60 days. The common carp (mean weight of 10±0.11g) were randomly allocated to four experimental treatments with three replications (25 pieces in each replication) including control treatment (no propionic acid) and three treatments which received formic acid (0.5, 1, 1.5 gr/ kilogram diet). The results indicated that growth parameters (final weight, weight gain, specific growth rate, condition factor, and FCR) were significantly different between the control and experimental treatments. The final weight, weight gain, specific growth rate, and condition factor in the propionic acid treatments had a significant increase compared to the control group (P < 0.05). The results of study showed that no significant difference in blood parameters were observed between treatments (P > 0.05). The highest lipase activity (21.73± 1.18 U/L) was observed in 1 g/kg propionic acid group (P < 0.05). Moreover, the highest protease (303.15± 4.16 U/L) and amylase activities (650.26± 10.05 U/L) were recorded in 1.5 g/kg propionic acid group (P < 0.05). According to obtained results, inclusion of propionic acid in common carp diet had a positive effect on the improvement of growth performance and digestive enzyme activities; therefore, a diet containing 1.5 g/kg propionic aid proposed to enhance growth performance and digestive enzyme activity of common carp.