Evaluated the Influence of Ascorbic Acid on Hatching Performance and Tolerance Against High Ammonia Concentration by Immersion of Kutum (Rutilus frisii kuttum) Fertilized Eggs

Abstract: The effect of L-ascorbic acid (AA) in four levels (0, 500, 1000 and 2000 mg L -1 ) on eyed egg and hatching rate, growth and viability of larva, and larval tolerance against high ammonia concentration stress in kutum Rutilus frisii kutum (Kamenskii, 1901) was evaluated. The fertilized eggs were placed in water containing different levels of AA for 4 h. The percentage of eyed egg and hatching were measured after 2 and 5 days respectively. After larva absorbed their yolk sac half of them were challenged by high ammonia concentration (5 mg L -1 ) and the others were reared for 60 days and growth factors and survival were recorded. The result shown that with increasing AA, percentage of eyed egg and hatching were increased and the highest eyed egg and hatching rate were in 2000 mg L -1 and had significantly difference with other treatments (P<0.05). The significant differences in larval tolerance against high ammonia concentration stress were observed between 2000 mg L -1 comparison to 0 and 500 mg L -1 treatments. No significant different were observed between growth parameters of treatments (P>0.05). Viability was different between experimental groups, but was not significant between 0 and 500 mg L -1 . According to our results, immersion of fertilized eggs of kutum in 2000 mg L -1 of AA may be beneficial