Hatchery And Growth Performance of Two Trout Pure Breeds, Salvelinus Alpinus And Salmo Trutta Fario, And Their Hybrid

An allelic cross between Salmo trutta fario and Salvelinus alpinus was carried out under con- trolled hatchery conditions. Survival to the eyed stage was significantly lower for the hybrid than for both purebreds. There were significant differences in survival in the eyed and yolk sac stages and from fertilization to the first feeding (p0.05). The hybrid did not display heterosis with respect to any hatchery property. During the first 45 days of nursing, there were significant differences between the purebreds and the hybrid in terms of weight gain, survival, feed conversion ratio and specific growth rate (p0.05). The hybrid was slightly heterotic (+1.69) with respect to survival how- ever no heterosis was observed in any other property to the first feeding stage

Discrimination of penaeid shrimps with PCR-RFLP analysis

A rapid polymerise chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis was designed to examine genetic differentiation of some penacid shrimps. Three hundred and fifty-six bp of cytochrome-b gene, a specific part of mitochondrial genome, was amplified with PCR to figure out differences between shrimp species Penaeus semisulcatus, Penaeus kerathurus. Parapenacus longirostris, and Metapenueus monoceros. PCR products Were digested with different restriction endonucleases (Ddel, Mbol. Mboll, and Msel.). None of the tested enzymes; alone, was able to distinguish between the four shrimp species, but with the combination of the results of two digestions, all of the species could be differentiated. It was shown that PCR-RFLP method can be used to expose fraudulent Substitutions of processed shrimps prior to marketing