) oncorhynchus mykiss( بررسي تاثير آستاگزانتين جيره غذايي بر ذخيره آستاگزانتين تخمك و قابليت لقاح در مولدين قزل آلاي رنگين كمان

The Effect of Different Astaxanthin Concentrations on Its Retention in Ovule and Consequently Fertilization Rate in Rainbow Trout (Oncorhynchus mykiss)

A completely randomized experimental design was conducted to evaluate the effect of dietary astaxanthin on egg astaxanthin content as well as fertilization rate in Rainbow trout (Oncorhynchus mykiss) brood stocks .Different levels of astaxanthin in fish diet containing0.07, 12.46, 33.33, 65.01 and 92.91 mg/kg constituted the treatments. Brood fish were reared under artificial photoperiodic system for a six-month period till sexual maturation, then prepared for artificial propagation. Homogenous sperm of four males (to avoid poor sperm quality they had been fed with diet supplemented with astaxanthin at a rate of 33.33 mg/kg) were used for fertilization. Female broods produced eggs containing astaxanthin, ranging from 2.035 to 29.79 mg/kg. There were significant differences observed among treatments as regards egg astaxanthin content (p<0.05).Although there werenʹt significant differences among experimental treatments as regards fertilization rate (p>0.05) but there was a significant difference observed as compared to control group (p<0.05). A significant regression relationship was observed between egg astaxanthin content and fertilization rate (p<0.05) that demons trated the positive effect of egg astaxanthin content on egg fertility and also confirmed the hormone like role of astaxanthin in fish fecundity.