Comparative effects of the arachidonic acid enrichment of the concentrated food and live feed on growth rate and reproductive indices in zebrafish, Danio rerio

In this study, the comparative effects of arachidonic acid (ARA) enrichment of the concentrated food and live feed (Artemia nauplius) were investigated on growth rate and reproductive indices in zebrafish (Danio rerio). Thirty-day-old juveniles (n = 400, with an average initial weight of 0.125 g) were randomly distributed in six treatments (each in three replicates) in eighteen 10-L aquariums (with a stocking density of 15 juveniles per aquarium). Fish were fed with concentrated diet containing three levels of ARA (0, 1 and 2% in the diet) and live feed (Instar II Artemia nauplii) in three levels of ARA (0, enriched with 1% and 2% of ARA) for 60 days until sexual maturity. The results of Two-Way ANOVA showed that the final body weight, body weight gain rate (%), and female’s reproductive indices were not affected by the combined effects of two factors; food type and ARA levels (p>0.05). Body weight in fish fed with concentrated diet containing 2% ARA was significantly higher than compared with the other treatments (p<0.05). The highest absolute and relative fecundities, and gonadosomatic index were obtained in females fed ARA-free concentrated diet, the enriched- Artemia with 1-2% ARA, and the enriched- Artemia with 1% ARA (p<0.05), respectively. The ARA enrichment in the concentrated diet only accelerated the growth rate of fish until sexual maturity for breeding. However, fish fed the enriched- Artemia with 1% ARA exhibited higher gonadal weight and much higher relative fecundity compared to other groups despite lower final weight (p<0.05). Based on the results and in order to improve the female’s reproductive performance in zebrafish hatcheries, it is suggested that fish fed the enriched Artemia with 1% ARA two months before reproduction.