Óleo essencial de alho na incubação de ovos de jundiá

Abstract

This study aimed to evaluate the effect of garlic essential oil (Allium sativum) on the fertility rate and hatching of silver catfish eggs, Rhamdia quelen, artificially incubated. The research consisted of two experiments (I and II) at the Institute for Research in Environmental Aquaculture (InPAA), Toledo-PR, from october to december 2014. It used a randomly experimental design with the four treatments and five repetitions. The treatments consisted on the introduction of garlic essential oil on the incubators of fish eggs with the levels of 0; 5; 10 and 20 and 0; 1; 3 and 5 mg L-1 of oil, on experiments I and II respectively. The fertilization rate was determined after the closing of the blastopore, approximately 10 hours post-fertilization and the hatching rate was calculated 24 hours post-fertilization, when it was observed the larvae shedding egg. It used the standard morphological larvae to determine the normal rate, with the aid of a stereoscopic microscope. On the experiment I the dosage of 5 mg L-1 promoted the biggest (p<0.05) rates of fertilization and hatching of the eggs. At levels of 10 and 20 mg L-1 was death from all embryos within 10h after fertilization. In the second experiment the dosage of 5 mg L-1 promoted best fertilization rates (p<0.01) and hatching (p<0.05) compared to other essential oil concentrations of garlic. The fertilization and hatching rates ranged from 65.80 to 83.70% and 57.60 to 71.40%, respectively. The essential garlic oil levels showed linear effect on the fertilization rates (p<0.01) and hatching (p<0.05). Garlic oil did not influence the normal larvae (p<0.05). It is recommended to use 5 mg L-1 essential oil of garlic to promote better rates of fertilization and hatching of silver catfish eggs artificially incubated