No abstract

Caracterização genética de seis plantéis comerciais de tilápia (Oreochromis) utilizando marcadores microssatélitesPalavras-chave: tilápia, microssatélite, distância genética. ABSTRACTTwo hundred and thirty five individuals from six commercial stocks of tilapias (Ceará, Chitralada, Israel, Nilótica, Taiwan and Red) from the Southeastern region of the country were genetically characterized using five microsatellite loci. The results suggest large genetic difference among the stocks, estimated through the fixation allele index (Fst = 0.3263), and a considerable loss of heterozigosity occurs in most of the stocks, according to the population inbreeding coefficient (Fis=0.0486). The Israel and Nilótica stocks were genetically similar (Ig=0.6663), while Chitralada and Taiwan showed less genes in common (Ig=0.2463). The Red stock was the most distinct stock.

No abstract

No abstract

In aquaculture, activities with anesthetic compounds are usually used in order to ensure the welfare of farmed fish, allowing handling out of water with decreased trauma by stress. Presently, there is no information about anesthetic action of eugenol in early life stages of Nile tilapia (Oreochromis niloticus). The objective of this study was to evaluate different concentrations of eugenol for larvae and juveniles of Nile tilapia. Sixty animals were used for each group of weight, group I = 0.02 g; group II = 0.08 g; group III = 0.22 g; group IV = 2.62 g; and group V = 11.64 g. The eugenol concentrations tested were 50, 75, 100, 125, 150 and 175 mg L -1 . No mortality was reported during the tests with eugenol. Tilapia larvae with 0.02 g and juveniles around 11.64 g can be anesthetized with eugenol concentrations between 150 and 175 mg L -1 , since they determine the shortest sedation time (23 and 72 seconds, for the group of lowest and highest weights, respectively).