Effect of different levels of folic acid on growth performance and blood indexes of Beluga fingerling (Huso huso Linnaeus 1758)

Abstract

Introduction: Folic acid plays an essential role in promoting aquatic immune.
Materials & Methods: In order to investigate the effect of folic acid diet on growth
performance, carcass composition, blood parameters of 270 beluga fingerling with an average
weight of 5-8 g with different levels of folic acid, including: 0.6 (as a control), 2.68, 3.72 and
4.84 mg/kg with three replications for 56 days were considered. The effect of experimental
treatments on growth performance and immune indices was investigated.
Results: Results showed that the effect of treatments on feed conversion, specific growth rate,
feed efficiency and weight gain was significant (P<0.05). Different levels of folic acid also
made a significant difference in the number of white blood cells (P<0.05); So that the lowest
value in the control treatment was 4.62 mg/kg and the highest was 6.75 mg/kg in the fourth
treatment. There was a significant difference in the number of lymphocytes between the
experimental groups, but no significant difference was observed in the number of neutrophils.
After carcass analysis, as expected, increasing dietary folic acid level caused a significant
increase in the percentage of crude protein in the carcass. So that the highest percentage of
crude protein in the third treatment was 2.13 mg/kg. Moisture, fat and ash carcass indices were
not significantly affected by experimental treatments.
Conclusion: The results of this experiment showed that by increasing the amount of folic acid
by 3.72 mg/kg, the fish will show better resistance in terms of immune and growth performance.