High Rate of Deformed Larvae among Gynogenetic Brown Trout (Salmo trutta m. fario) Doubled Haploids

Abstract

Mitotic gynogenesis results in the production of fully homozygous individuals in a single generation. Since inbred fish were found to exhibit an increased frequency of body deformations that may affect their survival, the main focus of this research was to evaluate the ratio of individuals with spinal deformities among gynogenetic doubled haploids (DHs) brown trout as compared to nonmanipulated heterozygous individuals. Gynogenetic development was induced by the activation of brown trout eggs by UV-irradiated homologous and heterologous (rainbow trout) spermatozoa. The subsequent exposure of the activated eggs to the high hydrostatic pressure disturbed the first cleavage in gynogenetic zygotes and enabled duplication of the maternal haploid set of chromosomes. The survival rate was significantly higher among gynogenetic brown trout hatched from eggs activated with the homologous UV-irradiated spermatozoa when compared to DHs hatched from eggs activated by the heterologous spermatozoa. More than 35% of the gynogenetic larvae exhibited body deformities, mostly lordosis and scoliosis. The percentage of malformed brown trout from the control group did not exceed 15%. The increased number of deformed larvae among DHs brown trout suggested rather a genetic background of the disease related to the fish spine deformities; however, both genetic and environmental factors were discussed as a cause of such conditions in fish.

Alterations in the rainbow trout (Oncorhynchus mykiss) eggs exposed to ionizing radiation during induced androgenesis

“…Both types of malformations were observed in the rainbow trout developing in the post‐ovulatory ageing eggs (Aegerter et al, ; Bonnet et al, ). Lordosis and scoliosis that are considered as rather genetically determined deformities (Boglione et al., ; Jagiełło, Zalewski, Dobosz, Michalik, & Ocalewicz, ) more likely resulted from the recessive alleles rather than reduced developmental competence of the irradiated eggs.…”

Developmental competence of eggs produced by rainbow trout Doubled Haploids (DHs) and generation of the clonal lines

“…Malnutrition by itself results in the body deformities due to the low intake of proteins, minerals and vitamins (Madsen & Dalsgaard, 1999). Increased homozygosity is usually followed by increased ratio of larvae with the vertebral deformities (Boglione et al, 2013;Jagiełło, Zalewski, Dobosz, Michalik, & Ocalewicz, 2017). Thus, it is reasonable to assume that clonal rainbow trout were more susceptible to developing scoliosis, lordosis or kyphosis.…”

Status of genetic and genomic approaches for delineating biological information and improving aquaculture production of farmed rohu, Labeo rohita (Ham, 1822)

“…Several techniques of chromosome manipulation have been used, such as physical shock (temperature and hydrostatic pressure), chemical treatment and UV/gamma‐ray treatment. These treatments resulted in polyploidy (triploids/tetraploids), gynogenetic or androgenetic fish populations (Johnstone & Stet, 1995; Felip et al, 2001; Jagiełło et al, 2017). The first attempts to induce polyploidy in farmed rohu used chemical treatment such as colchicine (Reddy et al, 1990).…”