The effect of Astaxanthin on sexual maturing and fecundity and survival larval of fighter fish (Betta splendens)

This study was aimed to evaluate the effect of dietary astaxanthin pigment on growth and maturation of bloodstocks and fry survival rates in fighter fish, Betta splendens. To this end, 48 fighter fish fry were prepared with 0.2gr.weight (the sexual ratio at fish is 1:1) then these fish A completely randomized design. Were divided to 4: groups with three replicates including group1 or control group (with additional astaxantine in diet), group2 (with 50 mg/kg supplementary astaxanthin in diet), group 3 (with 100 mg/kg supplementary astaxanthin in diet) and grpup4 (with 150 mg/kg supplementary astaxanthin in diet). Fish were reared for two month and then growth factors and some spawning indices were studied. According to the result although astaxanthin lead to lower FCR in treatment groups but it has no significant effects on other growth indices (P<0.05). On the other hand spawning were just recorded in treatment groups and treatment with 150 mg/kg supplementary astaxanthin had most hatched fry in first and second spawning in compare to other groups. Moreover, the highest survival rate of larva was observed in group 4. Based on the nutritional effects of astaxanthin and its positive impact on sexual maturation and survival rate of larva, we recommend using of this pigment (at least 50 mg kg-1 of feed) in the diet of fighter fish.