Comparison of performance of genome manipulated and standard tench, <Emphasis Type="Italic">Tinca tinca</Emphasis> (L.), groups under pond management conditions

A triennial performance test of five groups of tench, Tinca tinca (L.): Vodnany induced triploid V3n, Vodnany meiotic gynogenic Vgyn, diploid Vodnany V2n, Hungarian H2n and German G2n) in pond monoculture was carried out with diploid golden tench as control (C) to compute corrected weight of the groups tested. Survival rate ranged from 11.6% (V2n) to 30.6% (Vgyn) in yearlings, from 71.2% (V2n) to 91.5% (H2n) in 2 year-olds, from 60.0% (Vgyn) to 75.7% (V2n) in 3 year-olds while that of the control group was 8.5, 38.3 and 40.2% in the respective seasons. After three growing seasons the corrected weight of the fish in the groups H2n (254.6^bg), V3n (257.0^cg) and G2n (371.4^cg) was higher (P < 0.05, Tukey HSD test) than that from the C (183.3^ag) and V2n(205.6^abg) groups. Among the chromosomally manipulated groups, ANCOVA test found the least slaughtering value for Vgyn (84.3%); among the purebreds the highest value was found for H2n (87.32%), significantly differing from V2n and G2n strains. A high gonadosomatic index in females (2.94 vs. 0.44% in males) resulted in inferior slaughtering values.     

A review on the potential of triploid tench for aquaculture

Performance and physiological traits and health of spontaneous and induced triploid tench are reviewed. Triploidy is best induced with cold shock; with triploids exhibiting 13.5–51.5% better weight gain, 2.69–3.94% higher slaughtering value, 20–60% lower gonadosomatic index, 0.9–4.5% higher dry matter in flesh and up to 107% more flesh fat than diploids, if farmed untill post sexual maturity. Triploids exhibit more abdominal fat and less polyunsaturated fatty acids of the n-3 and n-6 groups in the flesh. Triploid females are sterile, while triploid males may produce aneuploid spermatozoa with varying DNA content (1–1.9n) which may initiate development of embryos. Triploids have milder seasonal dynamics in their erythrocyte profile than the diploids. Thinner diffusion distance in gills of triploids than in diploids is interpreted as adaptation to lower aerobic capacity. Triploids show neither stronger tendencies to anatomic malformations, nor have bigger affinity to parasitic diseases than the diploids. Production of triploid tench could be an economically interesting method of farming to higher marketable weight, bringing a relatively high product quality.     

Cryopreservation of tench, Tinca tinca, sperm: Sperm motility and hatching success of embryos

The aim of the present study was to elaborate cryopreservation methods for ex situ conservation of tench. Success of cryopreservation was tested during two series of experiments. The first set of experiments studied the effects of two types of cryoprotectants (DMSO and a combination of DMSO with propanediol at ratio 1:1) at concentrations of 8 and 10% and three different equilibration times in two different immobilization solutions (IS) (Kurokura 180 and Kurokura) before freezing (0.0, 2.0 and 4.0h after T(0)). The K4 cooling programme was used to freeze 1ml of cryoextended sperm using 1.8ml cryotubes. Main monitored parameter was hatching rate after using of cryopreserved sperm. The second set of experiments studied the volume effect of 0.5, 1 and 5ml straws and compared these with 1.8ml cryotubes as well as the effect of the cooling programme (K4 and L1). Following the results of the first study, a combination of DMSO and propanediol (ratio 1:1) at concentration of 10% was added to extended sperm in Kurokura 180 IS. Main monitored parameter was hatching rate after using cryopreserved sperm, supplementary parameters were sperm velocity and motility percentage assessed at 10s post-activation. Sperm was collected directly into IS and stored at 4 degrees C for 2.5h. Thereafter were sperm samples pooled, equlibred in IS (first set of experiments) or directly mixed with cryoprotectants (DMSO or a mixture of DMSO with propanediol at ratio 1:1) and transferred to 1.8ml cryotubes or straws (0.5, 1 and 5ml). Then the cryotubes/straws were directly transferred to pre-programmed PLANER Kryo 10 series III and cooled using two different cooling programmes including a slow cooling programme (a) named K4 (from +4 to -9 degrees C at a rate of 4 degrees Cmin(-1) and then from -9 to -80 degrees C at a rate of 11 degrees Cmin(-1)) and a rapid cooling programme (b) named L1 (directly from +4 to -80 degrees C at a rate of 20 degrees Cmin(-1)). Both slow (K4) and rapid (L1) cooled samples were held 6min at -80 degrees C. Finally, samples were transferred into liquid N(2). The frozen spermatozoa were thawed in a water bath (40 degrees C) according to the frozen volume and checked for fertilization and hatching rates. Percentage of sperm motility and sperm velocity were measured using video recorded frames. ANOVA showed a significant influence of frozen and fresh sperm in all treatments. The hatching rates of 33.8% were obtained when sperm was equilibrated for 0h before freezing in IS of Kurokura 180 and frozen with a 10% of mixture 1:1 of DMSO and propanediol into straws of 5ml and cooled using program L1. The velocity of frozen-thawed spermatozoa ranged from 31 to 46microms(-1) and in post-thawed sperm was not significantly different according to frozen sperm volume, but a higher velocity was obtained when sperm was fast frozen using programme L1. A large volume of frozen sperm could reveal the best procedure for freezing, but also for simulating methods of artificial propagation for future practical use of frozen tench sperm at a large scale.     

Short-term storage of ova of common carp and tench in extenders

In a study of the effect of short-term storage on the hatching rate of common carp Cyprinus carpio and tench Tinca tinca ova in vitro in various extenders at 21° C under aerobic conditions, the best extender for 30 min storage for common carp appeared to be Dettlaff 1. This gave the same hatching rate as controls without extender (55% v. 56%). For 60 min storage of ova, the best extenders were Dettlaff 2 (24% hatching rate) and Dettlaff 3 (30%), but hatching was significantly lower than in the control (58%). In carp ovarian artificial fluid (CAF) extender, the hatching rate of common carp ova was also high after 10 min, but decreased to 12% after 30 min. In tench, the hatching rate of ova increased after 10 min storage in Dettlaff 5 extender (44%) compared to the control (41%) without extender. However, it was significantly lower after storage in Dettlaff 1, 2, 3, 4, 5 and CAF extenders for 20, 30 and 60 min, compared to controls. Malformations (10–50%) were observed in the tench second control groups without extender after 10, 20 and 30 min storage of ova.     

Differences in biochemical profiles among spawners of eight common carp breeds

Eight breeds of common carp (Cyprinus carpio L.) spawners reared under identical conditions and sampled in spring after over‐wintering were examined in order to compare their basic biochemical blood profiles. The breeds compared were: Amur wild carp (AS), Ropsha scaly carp (ROP), Ukraine scaly carp (US), Northern mirror carp (M72), South Bohemian mirror carp (BV), Israeli mirror carp (Dor 70), Hungarian mirror carp (M2) and Tata scaly carp (TAT). Significant differences were found among breeds in glucose concentration (GLU), total protein concentration (TP), triacylglycerols concentration (TAG), and calcium (Ca) and phosphorus (P_i) concentration. No differences were observed in aspartate transaminase activity (AST) or alanine aminotransferase activity (ALT). The highest glucose, total protein, and calcium (Ca) concentrations were found in AS (GLU 8.3 ± 1.2 mmol L^?1, TP 32 ± 3 g L^?1, Ca 2.42 ± 0.22 mmol L^?1). High values of triacylglycerol concentration (TAG) were found in ROP (1.94 ± 0.52 mmol L^?1). Phosphorus (P_i) concentration was highest in M2 (3.82 ± 1.34 mmol L^?1). Amur wild carp and breeds originating therefrom (ROP, US, and M72) had significantly higher values of TP (P < 0.05), TAG (P < 0.05), and Ca (P < 0.01) and significantly lower values of P_i (P < 0.05) than did the other breeds. Scaly breeds had higher values of glucose (P < 0.01), TP (P < 0.01), ALT (P < 0.01), and Ca (P < 0.01) and significantly lower values of P_i (P < 0.01) than did mirror carp. Significant (P < 0.01) sex‐related differences were found in GLU, TAG and Ca concentrations.     

Freeze-thawing as the factor of spontaneous activation of spermatozoa motility in common carp (Cyprinus carpio L.)

In the present study, we investigated the possibility of spontaneous carp spermatozoa activation by freeze-thawing. To evaluate this, the parameters of spermatozoa motility percentage, velocity, ATP content level and fertility rate of sperm were used. The motility and velocity of spermatozoa activated by freeze-thawing were characterized by motile spermatozoa with a median value of 16% and a velocity of 98 μm/s. In addition, the motility and velocity of sperm from the thawed samples were significantly lower than in the control (median value of 100% for sperm motility and 175 μm/s for sperm velocity). Furthermore, a spontaneously activated spermatozoa motility terminated within five minutes post-thaw time. After freeze-thawing the ATP level significantly decreased with post-thaw time (46 nmol ATP/10⁹ and 10 nmol ATP/10⁹ at 25 s and 10 min after thawing, respectively). Fertility of spermatozoa was not significantly affected within 10 min post-thaw. On the other hand, the fertility of frozen-thawed sperm was significantly lower if compared to fresh sperm. We conclude that the freeze-thawing procedure spontaneously activated spermatozoa motility in common carp. However, this activation did not negatively affect the fertility of frozen-thawed sperm.     

Does triploidization produce functional sterility of triploid males of tench <Emphasis Type="Italic">Tinca tinca</Emphasis> (L.)?

Triploidy interferes with gametogenesis in all fish species tested so far. In fish it results in complete female sterility however, males are still able to develop testis. The reason why sterility levels in triploid fishes differ among species and between sexes is unclear. In the present study the reproductive capacity of triploid males of tench was studied. Flow cytometry revealed sperm cells of triploids to be largely aneuploid with high mosaic DNA, oscillating from haploid DNA to diploid DNA content. Analysis of variance showed an insignificant influence of ploidy level on the percentage of motile spermatozoa, as well as on spermatozoa velocity. Experimental crosses between normal diploid female and triploid males resulted in the appearance of triploid progeny, which exhibited genotypes composed of microsatellite alleles inherited from the founder female and additional allele derived from the donor male. We can conclude that the triploid males analysed in the present study were capable to fertilize eggs derived from diploid females.     

Water polluted by 17α‐methyltestosterone provides successful male sex inversion of common carp (Cyprinus carpio L.) from gynogenetic offspring

This study investigated the effects of oral treatment and water pollution by 17α‐methyltestosterone (MT) on the masculinization of common carp, Cyprinus carpio, gynogenetic offspring. The oral administration of MT results in detectable levels of the steroid in the water of recirculating systems. Both modes of MT administration (oral/water pollution) caused a high level of masculinization (61.5–100%) of gynogenetic offspring of common carp.