Investigation of the hatching performance, growth, survival and tolerance against high ammonia concentration by enrich water incubation of carp (Cyprinus carpio) eggs with a-tocopherol

The effect of a-tocopherol (Vitamin E) on eyed egg and hatching rate, growth and viability of larva, and larval tolerance against high ammonia concentration stress of common carp Cyprinus carpio (Linnaeus, 1758) was evaluated. The fertilized eggs were placed in water containing 4 levels of a-tocopherol (0, 300, 500 and 1000 mg L1) for 5 h. The percentage of eyed egg and hatching were measured after 2 and 3 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 the highest eyed egg and hatching rate were in 1000 mg L-1 but had not significantly difference with other treatments (P<0.05). The significant differences in larval tolerance against high temperature stress were not observed between treatments. No significant different were observed between growth parameters of treatments (P>0.05). Viability was different between experimental groups and was not significant between 0 and 300 mg L-1. According to present results, enrich incubation water of carp eggs by 1000 mg L-1 of a-tocopherol may be beneficial.