Formation of chromosome aberrations in androgenetic rainbow trout Oncorhynchus mykiss.

Residues of maternal nuclear DNA in the form of chromosome fragments were observed in the healthy and morphologically normal androgenetic rainbow trout Oncorhynchus mykiss. A hypothetical model for formation of chromosome re-arrangements caused by the incomplete maternal nuclear DNA inactivation in the androgenetic rainbow trout was proposed in the present paper.

Chromosome rearrangements and survival of androgenetic rainbow trout (Oncorhynchus mykiss).

The purpose of this work was to quantify the impact of spontaneous and X-radiation-induced chromosome rearrangements on survival rate of androgenetic rainbow trout (Oncorhynchus mykiss). Various doses of X irradiation (50, 150, 250, 350 Gy) were used for inactivation of nuclear DNA in oocytes. After the irradiation, eggs were inseminated with normal sperm from 4 males derived from a strain characterized by Robertsonian rearrangements and length polymorphism of the Y chromosome.

Effects of UV irradiation and hydrogen peroxide on DNA fragmentation, motility and fertilizing ability of rainbow trout (Oncorhynchus mykiss) spermatozoa.

Preservation of DNA integrity is essential for protection of sperm quality. This study examined, with the use of comet assay, DNA fragmentation of rainbow trout (Oncorhynchus mykiss) spermatozoa subjected to UV irradiation (2,075 microW/cm(2), 0-15 min) or oxidative stress induced by hydrogen peroxide (0-20mM). Sperm motility and fertilizing ability were also measured.

Blood cells in rainbow trout Oncorhynchus mykiss milt: relation to milt collection method and sampling period.

The presence of blood cells in milt of rainbow trout (Oncorhynchus mykiss) collected every week between the middle at the end of the spawning season, either by stripping or by catheterization was investigated. Basic sperm biological and biochemical characteristics were also evaluated. Because milt often becomes contaminated with blood during collection, we also studied the influence of experimental blood contamination on sperm motility and biochemical parameters of seminal plasma.

The stability of telomereless chromosome fragments in adult androgenetic rainbow trout.

The study provides new data on the stability of gamma radiation-induced chromosome fragments of a putative maternal nuclear genome in an androgenetic vertebrate, rainbow trout (Oncorhynchus mykiss Walbaum). The fragments were found in five of 16 examined individuals and they were mostly centromeric parts of metacentric or subtelocentric chromosomes. Chromosome fragments were identical in all cells of a given androgenetic individual, indicating that segregation of chromosome fragments is active from the early cell divisions.

Cell-mediated immunity in yellow forms of rainbow trout.

The aim of the present study was to investigate possible pleiotropic effects of the genotypes controlling the palomino and albino coloration on blood phagocyte and lymphocyte activity. The results showed that the wild coloured trout has a higher metabolic and potential killing activity of blood phagocytes, compared to albino and palomino coloured trout. The proliferative response of blood lymphocytes stimulated by ConA or LPS indicated a similar pattern.

Androgenesis in rainbow trout using cryopreserved spermatozoa: the effect of processing and biological factors.

In addition to producing homozygous lines for biomedical and genomic research and monosex stocks for commercial purposes, androgenesis is the biotechnology considered most promising and reliable for recovering complete nuclear genome information from cryopreserved fish cells. That is because procedures of cryopreserving spermatozoa, contrary to procedures for oocytes or entire eggs, are being well developed. Application of androgenesis in genome banking programs addresses the needs of both the aquaculture industry (safeguard for valuable strains and lines) and natural resource conservation (in vitro protection of endangered species or populations).

Effect of extender composition and equilibration time on fertilization ability and enzymatic activity of rainbow trout cryopreserved spermatozoa.

The effects of extender composition and equilibration time on fertilizing ability of cryopreserved spermatozoa from rainbow trout, Oncorhynchus mykiss, were investigated. In addition, enzyme activity in supernatants from thawed sperm was assessed. The use of the two extenders: Erdahl & Graham's + 10% DMA (dimethyl acetamide) + 10% egg yolk and 0.

Activity of aspartate aminotransferase and acid phosphatase in cryopreserved trout sperm.

Milt of brown, rainbow and brook trout was cryopreserved. Activity of aspartate aminotransferase (AspAT) and acid phosphatase was assayed both in supernatants and in spermatozoa obtained from thawed sperm samples; additionally, post-thaw motility was evaluated. Enzyme activities differed according to fish species and were strongly affected by the type of cryoprotectant used.