Kyle J. Schneider

Inheritance of Sparkling Scales (Ginrin) Trait in Ornamental Koi Carp

AbstractThe purpose of this study was to investigate mechanisms of inheritance of the sparkling scales (ginrin) trait in ornamental koi, a variant of Common Carp Cyprinus carpio. The fish segregations of ginrin : nonginrin were recorded in three F1 progenies obtained by crosses of ginrin × nonginrin and 16 F2 progenies obtained by crosses of ginrin × ginrin and nonginrin × nonginrin. The segregations of ginrin : nonginrin in most F1 progenies did not differ significantly from the 1:1 Mendelian ratio, while crossing nonginrin fish from F1 progenies resulted in the appearance of only nonginrin fish in F2. Based on these data, it was suggested that the ginrin trait in koi is controlled by a dominant mutation of one gene (Gr/gr): fish with genotypes GrGr and Grgr have ginrin phenotype, while fish with genotype grgr do not possess this trait. In most analyzed F2 progenies obtained by crosses of ginrin × ginrin, the ginrin : nonginrin segregations were statistically different from the 3:1 and 2:1 theoretical ra...

The effect of water temperature on growth and survival of largemouth bass during feed training.

Abstract Water temperature could be an important factor during the feed training phase of largemouth bass Micropterus salmoides production, as it could affect appetite and starvation time. We evaluated three water temperatures during largemouth bass feed training. Pond-reared largemouth bass fingerlings (weight = 2.1 ± 0.6 g [mean ± SE]) were randomly stocked into twelve 0.5-m3 polyethylene cages to achieve a stocking density of 350 fish per cage. The cages were suspended in six 3,800-L polyethylene tanks with a common water source housed in a greenhouse with four replicate cages per water temperature treatment (20, 24, and 28°C). Each tank contained two cages, and there were two tanks per treatment temperature. In each cage, fingerlings were initially fed freeze-dried krill, then gradually weaned onto a commercial pellet (floating trout feed; 1.5 mm) over a 24-d period according to an established training protocol. At harvest, the average weight and the percentage of fish successfully trained to commerci...

Koi ×Goldfish Hybrid Females Produce Triploid Progeny when Backcrossed to Koi Males

Abstract Hybrids of koi (an ornamental variant of the common carp Cyprinus carpio) and goldfish Carassius auratus auratus were produced by artificial spawning. All 3-year-old F1 hybrid males examined were sterile, whereas some F1 hybrid females were fertile and produced eggs after hormonal injection. Backcross progeny were obtained by using intact koi sperm to inseminate eggs from F1 hybrid females; gynogenetic progeny were obtained by inseminating eggs from F1 hybrid females with koi sperm that was genetically inactivated by ultraviolet irradiation. Flow cytometric analysis of DNA content indicated that the backcross progeny were triploid, while the gynogenetic progeny, pure koi, pure goldfish, and F1 hybrids were all diploid. The triploidy of backcross progeny obtained without application of any treatment to the eggs demonstrates that the koi × goldfish hybrid females produce diploid eggs. Received November 11, 2011; accepted February 18, 2012

Gonad Development in Triploid Ornamental Koi Carp and Results of Crossing Triploid Females with Diploid Males

AbstractGonad development in 4-year-old triploid and diploid ornamental koi, a variant of Common Carp Cyprinus carpio, from corresponding heat-shocked and control progenies was investigated. Diploid males were normally mature. Triploid males from heat-shocked progeny demonstrated development of testes typical for triploid fish; triploid males did not release sperm and their testes had a pinkish color and were significantly reduced in size. Diploid females were normally mature and their gonadosomatic indices (GSIs) varied from 7.5% to 30.7% and the mean value was 21.3%. Triploid females had unexpectedly well-developed ovaries, which were filled with fully grown oocytes; their GSIs varied from 4.2% to 30.1% and the the mean value was 17.0%. Four triploid koi females released large quantities (from 260,000 to 394,500 eggs per female) of ovulated eggs after hormonal injection. Eggs from triploid females were fertilized with sperm from normal diploid koi males. Mass mortality of hatched larvae occurred at the ...

Effect of ploidy on scale‐cover pattern in linear ornamental (koi) common carp Cyprinus carpio

The effect of ploidy on scale-cover pattern in linear ornamental (koi) common carp Cyprinus carpio was investigated. To obtain diploid and triploid linear fish, eggs taken from a leather C. carpio female (genotype ssNn) and sperm taken from a scaled C. carpio male (genotype SSnn) were used for the production of control (no shock) and heat-shocked progeny. In heat-shocked progeny, the 2 min heat shock (40° C) was applied 6 min after insemination. Diploid linear fish (genotype SsNn) demonstrated a scale-cover pattern typical for this category with one even row of scales along lateral line and few scales located near operculum and at bases of fins. The majority (97%) of triploid linear fish (genotype SssNnn) exhibited non-typical scale patterns which were characterized by the appearance of additional scales on the body. The extent of additional scales in triploid linear fish was variable; some fish had large scales, which covered almost the entire body. Apparently, the observed difference in scale-cover pattern between triploid and diploid linear fish was caused by different phenotypic expression of gene N/n. Due to incomplete dominance of allele N, triploids Nnn demonstrate less profound reduction of scale cover compared with diploids Nn.

Spontaneous polyploidy, gynogenesis and androgenesis in second generation (F2) koi Cyprinus carpio × goldfish Carassius auratus hybrids

The objective of this study was to characterize the genetics of second generation (F2 ) koi Cyprinus carpio × goldfish Carassius auratus hybrids. Spermatozoa produced by a novel, fertile F1 male were found to be diploid by flow-cytometric analysis. Backcross (F1 female × C. carpio male and C. carpio female × F1 male) juveniles were triploid, confirming that female and male F1 hybrids both produced diploid gametes. The vast majority of surviving F2 juveniles was diploid and small proportions were aneuploid (2·1n-2·3n and 3·1n-3·9n), triploid (3n) and tetraploid (4n). Microsatellite genotyping showed that F2 diploids repeated either the complete maternal or the complete paternal genotype. Fish with the maternal genotype were female and fish with the paternal genotype were male. This demonstrates that F2 diploids were the result of spontaneous gynogenesis and spontaneous androgenesis. Analysis of microsatellite inheritance and the sex ratio in F2 crosses showed that spontaneous gynogenesis and androgenesis did not always occur in equal proportions. One cross was found to have an approximate equal number of androgenetic and gynogenetic offspring while in several other crosses spontaneous androgenesis was found to occur more frequently than spontaneous gynogenesis.

Evidence of Female Heterogamety in Largemouth Bass, Based on Sex Ratio of Gynogenetic Progeny

Abstract Meiotic gynogenetic progeny in largemouth bass Micropterus salmoides have been obtained by inseminating largemouth bass eggs with UV-irradiated sperm from white bass Morone chrysops or striped bass Morone saxatilis and suppressing the second meiotic division by hydrostatic pressure. The sex composition of gynogenetic progeny was determined by dissection or ultrasound investigation of 1-year-old fish. Among the 21 fish analyzed, 7 fish (33.3%) were male and 14 fish (66.7%) were female. The presence of males in meiotic gynogenetic progeny suggests the existence of female heterogamety (WZ females, ZZ males) in largemouth bass. Received January 19, 2012; accepted June 4, 2012