Molecular investigation of banana shrimp [P. merguiensis] populations from Persian Gulf and Oman sea using microsatellite markers

Molecular investigation of important commercial shrimp species is one of the main goals to find out the pure populations and brood stocking of marine resources. The purpose of the present study was to study the population of P. merguiensis and determining the extent of genetic diversity of this species. Samples were collected from three major distribution areas in the Persian Gulf and Oman Sea. Molecular investigation was carried out using microsatellite markers. Only five out of the eight primers of P. merguiensis produced good amplified PCR products with fixed annealing temperature. The rest of the primers were either not easily amplified or produced nonspecific bands. Seven alleles were found to be unique to each of the three populations of P.merguiensis. Occurrences of heterozygosity deficiency were found at most loci. These heterozygosity deficiencies in observed heterozygosity in comparison to expected heterozygosity may be due to inbreeding, genetic drift and consequences of illegal overharvesting of P. merguiensis in the studied areas as well. Deviation from Hardy-Weinberg Equilibrium in both studied species was significant in most microsatellite loci [p<0.001]. We observed deviation from HWE in most loci with hetrozygosity deficits. The genetic variation results showed that the pairwise Fst values were significant between studied populations. The assignment test revealed high gene flow between Hormoz and Jask and restricted genetic flow between Guatr and Hormoz populations. It seems that the changes in immigration patterns of populations between Hormoz, Jask and Guatr areas depend on the influence of Persian Gulf currents or the life cycle of P. merguiensis in studied areas. Alternatively, the presence of ecological barriers such as mangrove forests may result in restricted genetic flow between Guatr and both Hormoz and Jask populations

[Histological study of rainbow trout [Oncorhynchus mykiss] after administration of 17 alpha- methyl testosterone]

Study of histological changes in gonads of fish received a variety treatment of 17-alpha methyl testosterone. Rainbow trout [Oncorhynchus mykiss]. Descriptive study. Application of 17 - alpha methyl testosterone [MT] using immersion and/or oral administration methods in two seasons and in 5 and 11 treatments along with a control group with no hormonal treatment for each season, respectively. In immersion method eyed eggs and larvae were immersed in 250 mg/l MT bath for 2 hours twice 4 and 8 days apart. In oral administration method newly feeding larvae were fed with food containing 0.5, 1, 2, 3 and 30 ppm MT for 60, 70, 90 and 120 days after commencing active feeding. Histological examination was carried out on gonads of 20 fish from each treatment as well as control group at the age of 11 and 24 months for two seasonal groups of fish, respectively. Masculinization and sterilization were successfully carried out on rainbow trout by using a variety treatment of MT. A range of histological changes were observed in gonads of different treatment groups. This included histologically normal males, normal females, intersex, totally atrophic gonads and sterile fish. In some testes a number of follicles were seen among the mass of spermatozoa. In intersex gonads both male and female cell types were observed alongside each other. Sterile gonads could be categorized as: sterile males, sterile females as well as completely sterile containing residual male cells, residual female cells and no cells at all, respectively. in a number of specimens spermatozoan cysts were typically observed. Application fo 17-alpha methyl testosterone to rainbow trout at early stages of development could dramatically change the histological profile of gonads ranging from functional testes, to intersex, to sterility