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

Abstract

Poor quality eggs produced by the fully homozygous doubled haploids (DHs) may impair generation of clonal lines in fish species. In the present research, gynogenetic development of rainbow trout (Oncorhynchus mykiss) was induced in eggs originated from the DH females. Eggs were activated with the UV-irradiated grayling (Thymallus thymallus) spermatozoa and subjected to the high hydrostatic pressure (HHP) shock to provide diploid clonal individuals. Only two of four DH females produced eggs that were successfully activated by the irradiated spermatozoa and subsequently developed into the gynogenetic embryos. Survival rates of rainbow trout from the clonal lines equalled 21.5% and 19.8% during embryogenesis and decreased after hatching to 18.6% and 14.9%, respectively. Some of the dead rainbow trout clones collected between hatching and swim-up stage were emaciated and exhibited spinal deformities including scoliosis. Provided results confirmed limited developmental competences of eggs produced by rainbow trout DH females. Clonal rainbow trout developing in such eggs exhibited reduced survival and increased frequency of the body abnormalities.

Inter-clutch egg differences and androgenesis in rainbow trout (Oncorhynchus mykiss, Walbaum 1792)

“…for androgenetic development (Table 1). Variation in efficiency of chromosome set manipulations in relation to origin of gametes have been observed before when induced androgenesis and gynogenesis in salmonids and sturgeons (Ocalewicz et al 2013;Fopp-Bayat & Ocalewicz 2015;Jagiełło et al 2018, Ocalewicz et al 2020. Such inter-clutch differences in the survival rates of androgenotes could result from physiological and/or molecular differences in eggs of different origins.…”

“…In rainbow trout, when eggs are not collected within a maximum of 5-7 days after ovulation, biochemical, histological, cellular and molecular changes in eggs may result in their reduced developmental competence (Aegerter & Jalabert 2004). Although hatching and malformation rates (Aegerter & Jalabert 2004;Jagiełło et al 2018;Polonis et al 2019) are considered the most effective indicators of fish egg quality, other biomarkers, including the distribution of lipid droplets (Mansour et al 2007;Ciereszko et al 2009;Polonis et al 2019), pH of the ovarian fluid (Aegerter & Jalabert 2004) and quality and quantity of maternal transcripts (Sullivan et al 2015;Ocalewicz et al 2020) have been proposed for use in assessing the developmental competence of salmonid fish eggs.…”

Preliminary Identification of Candidate Genes Related to Survival of Gynogenetic Rainbow Trout (Oncorhynchus mykiss) Based on Comparative Transcriptome Analysis

“…Both reports indicate that differences in the expression of the maternal genes primarily result from differences between mothers. In the androgenetic and gynogenetic experiments, the differences in survival rates of embryos developing in eggs originating from different females have been reported by several authors [13][14][15], among others. Similar events were also observed in the gynogenetic experiment described here, where significant differences in the survival rates between gynogenetic DH rainbow trout developing in eggs originated from four gamete donors were shown.…”

“…Rainbow trout utilized as gamete donors originated from the spring spawning broodstock raised in the Department of Salmonid Research, Inland Fisheries Institute in Olsztyn, Rutki, Poland. The number of dams and sires used in the research was determined to meet the requirements for the statistical analysis and it was based on the previous studies concerning the chromosomes set manipulations in fish [12,13,15]. Semen was taken from four males, pooled and kept in the plastic box.…”

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

“…Low‐quality fish eggs may have changed abundance of particular maternal transcripts (Aegerter, Jalabert, & Bobe, ; Sullivan, Chapman, Reading, & Anderson, ), coalesced lipid droplets (Mansour, Lahnsteiner, & Patzner, ), impaired function of the spindle microtubules (Aegerter, Jalabert, & Bobe, ) and altered permeability of the egg membrane (Rime et al, ). Embryos developing in such eggs quite often exhibit body malformations (Bonnet, Fostier, & Bobe, ; Jagiełło, Dobosz, Zalewski, Polonis, & Ocalewicz, ; Nowosad, Sikora, & Kucharczyk, ). The post‐ovulatory oocyte ageing has been suggested to be influenced by the reactive oxygen species (Lord & Aitken, ; Takahashi et al, ) that are generated within the normal cellular metabolism; however, external factors including ionizing radiation applied when induced androgenesis may significantly increase their production.…”