Effect of Livergol on growth indices and gonadal development in different levels of dietary lipid in goldfish (Carassius auratus)

Fat plays an important role as the source of energy and essential fatty acids for growth and development of fish. Excessive dietary fat can penetrate into the liver and accumulate in it, and resulting fatty liver disease. The objective of this study was to evaluate the effects of dietary supplementation of Livergol drug on growth parameters and gonadal development in different levels of fat in goldfish diets. For this experiment, 9 diets of different were prepared with 3 levels of 0, 0.2 and 0.5% of Livergol and three levels of 9, 12 and 15% fat. 540 individuals of gold fish were applied in this study. The feeding trial was carried out to complete the reproductive season of fish. Gonadal sampling was performed for detection of gender and determination of sexual development every 45 days after feeding with experimental diets. After the end of experimental period, fish growth indices (end weight, percentage of weight gain, weight gain, status index, specific growth rate, survival rate and food conversion ratio) were investigated. The results showed that the final weight, body weight gain, body weight gain, specific growth rate, status index and feed conversion ratio were significantly different in the experimental treatments (P≤ 0.05), While survival did not show significant difference between treatments (P≥ 0.05). The highest growth indices were observed in treatment 8 (fat 15% + livergol 0.5%). In this experiment, the comparing of ovarian stages of fish fed with different diets indicated that all stages of ovarian stages except treatment 6 were similar in all treatments, but delay of the vitellogenin and development phases were observed in treatment 6 containing 15% fat and without livergol drug.