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Selection of optimal spawner-pairs based on the polymorphism of microsatellite loci in a partially-tetraploid fish species (Coregonus lavaretus)

Kaczmarczyk D., Fopp-Bayat D., Wiśniewska A.

Environmental Biotechnology

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2015

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Vol. 11, No. 1

20--25

EN

Many species that are in danger of extinction require human support in the form of captive-breeding programs to help maintain their populations in the wild.When breeding in captivity, it is important to select breeding pairs that will create the most genetically diverse progeny. Based on the polymorphism of their microsatellite loci, breeding pairs of diploid land animals have been successfully selected. In this theoretical paper, we asked how to adapt this technique to the selection of spawner pairs for restocking populations of partially tetraploid fish species. To test our calculation techniques, we used actual data on the polymorphism of the loci of captured whitefish (Coregonus lavaretus). The data enabled calculations showing which spawner pairs would create the most genetically diverse cohort of offspring if they were bred. Themethod presented in the paper can be used for breeding fish in aquaculture conditions to help conserve species.

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Exposure of whitefish (Coregonus lavaretus) eggs to native or chemically spiked sediments from Lake Thun does not lead to abnormal gonad development

Bernet D., Wahli T., Gerecke A., Segner H.

Environmental Biotechnology

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2011

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Vol. 7, No. 1

17-29

EN

A high number of whitefish, Coregonus lavaretus, from Lake Thun, Switzerland, display gonad malformations. We tested the hypothesis that exposure to sediment-borne contaminants during the embryonic life results in the development of malformed gonads later in ontogeny. The investigated contaminants were 2,4,6-trinitrotoluene (TNT), which may leak from residues in the lake sediments as consequence of former ammunition dumping into Lake Thun, as well as sulfonated naphthalene formaldehyde condensates (SNFC), which are introduced into the lake from wastewater disposals of a nearby tunnel construction site. Experimentally, whitefish eggs were exposed during 52 days from fertilization until hatching to a) an artificial sediment (control), b) an artificial sediment spiked with TNT (0.5mg*kg-1 dry weight), c) SNFC compounds dissolved in water (3µg*l-1 of each naphthalene-1-sulphonate, naphthalene-2-sulphonate, naphthalene-1,5-disulphonate, naphthalene-2,7-disulphonate), and d) sediment from Lake Thun sampled in an ammunition dumping area. To mimic in situ exposure of the eggs to the sediment-water-interface under laboratory conditions, we developed a novel contact incubation technique. After hatching, fish were reared in tap water for three years until they reached sexual maturity, and were then examined for the presence of gonad malformations. No malformations were observed in the control, in the TNT and SNFC treatment groups. In fish incubated during the embryonic stage on Lake Thun sediment, 2 out of 117 adult males (1.7%) displayed malformed gonads, which is significantly lower than levels of gonad malformations in wild whitefish from Lake Thun (on average 29% in males, 12% in females). The results from our experiment provide no evidence that sediment contamination with TNT or SNFC compounds is a causative factor for the induction of gonad malformations in Lake Thun whitefish.

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Relative quantification of CYP1A gene expression in whitefish (Coregonus lavaretus) exposed to benzo[a]pyrene

Brzuzan P., Jurczyk Ł., Łuczyński M. K., Góra M.

Environmental Biotechnology

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2005

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Vol. 1, No. 1

11--15

EN

The expression of CYP1A (cytochrome P4501A) can be induced by a number of aromatic compounds in teleost fishes. We developed a real-time PCR assay for measuring relative quantities (RQ) of CYP1A mRNA in whitefish (Coregonus lavaretus). To test for the usefulness of the assay we performed a treatment study, using benzo[a]pyrene (B[a]P) a model CYP1A inducer. Primers for the CYP1A gene were adapted from the literature, whereas those for [beta]-actin (endogenous control) were designed from a region that was found to be conserved among salmonid [beta]-actin genes. A group of hatchery raised whitefish, with an average body mass of 15 g and total length of 12 cm were given an intraperitoneal injection (10 mg/kg) of B[a]P in corn oil (2 mg B[a]P/ml corn oil) or corn oil alone (Control). After 48 h, whitefish liver, head kidney and brains were collected for mRNA isolation and analysis. In all three tissues sampled, CYP1A mRNA was affected by treatment with B[a]P. Head kidney tissue showed the greatest induction potential (RQ=11.00) from base levels (RQ=1.00), followed by liver (RQ=9.45), and brain (RQ=3.76). These results demonstrated that CYP1A was highly inducible by B[a]P in whitefish head kidney and liver, and to some extent, in brain tissue. The approach presented here has the advantage of providing rapid and accurate measures of CYP1A induction in various tissues of fish responding to PAH contaminant exposure.