Effect of Formic Acid and Biotin Supplementation on Growth Performance and Survival of the Carp Fish Challenged with Vibrio parahaemolyticus Infection

The present study was designed to examine the dietary supplementation effect of formic acid, biotin or their combination on growth performance, digestive enzymes activity, some serum biochemical parameters, histopathological alterations and the survival of common carp fish (Cyprinus carpio) challenged with Vibrio parahaemolyticus infection. Approximately, 150 carps (50±3g) were divided randomly into five experimental groups in triplicate, G1: negative control; without any supplementation; G2: positive control; without any supplementation then challenged with IP injection with (1x105CFU/ 0.2ml/fish) V. parahaemolyticus on day 45; G3: carps were fed a prepared ration supplemented with 0.2% formic acid for 45 days then challenged as previously; G4: carps were fed a prepared ration supplemented with 0.06mg/ kg biotin for 45 days then challenged; and G5: carps were supplemented with both formic acid and biotin for 45 days then challenged. After 45 days of feeding trials, a higher weight gain % and specific growth rate with lower FCR were observed in G5, G3, and G4, respectively, than the control groups. Total protein, albumin, globulin, and digestive enzymes activity were significantly higher in all the supplemented groups when compared with the control, especially G5. After 45 days, decreased levels of ALP, ALT, AST, creatinine, and urea were recorded in all the supplemented groups compared to the control. The survival rate of carps challenged with Vibrio parahaemolyticus increased from 46.6% in G2 up to 93.3, 86.6 and 83.3% in G5, G3, and G4, respectively. Histopathological alterations revealed the appearance of normal structure of hepatic, renal and splenic tissue for G5 compared with G3 and G4, respectively. Generally, it could be stated that formic acid and biotin could be good choices as dietary additives targeting the enhancement of growth performance and survival rate.