Induced meiotic gynogenesis in tench, Tinca tinca (L.) using irradiated heterogenic sperm

Effects of the starting time and duration of cold shock, as well as the source of heterogenic sperm on the percentage of viable gynogenic larvae (PVGL) in tench were studied. The DNA in sperm of red common carp (Cyprinus carpio var singuonensis) was inactivated by ultraviolet radiation prior to use to induce meiotic gynogenetic development in tench. In experiment 1, tench eggs were cold-shocked for 30 min starting at 1, 3, 5, 7, 10 and 15 min post activation. In experiment 2, cold shock began 5 min after activation and lasted for 10, 20, 30, 40, 50 min, respectively. Each experiment was run in triplicate using 3 tench females, and one group not treated with cold shock was included in each experiment to serve as a control group. In experiment 3, sperm of bigmouth buffalo (Ictiobus cyprinellus), red common carp or grass carp (Ctenopharyngodon idella) was used to induce gynogenesis in tench with a 20-min cold shock starting 5 min post activation. The results showed that PVGL from the control group was very low (0.11–0.47%). In experiment 1, the highest average PVGL (9.60%) was observed when cold shock treatment was applied 5 min post activation. When cold shock treatment was started 5 min post activation, duration of cold shock affected PVGL. Cold shock lasting 20 min resulted in the highest average PVGL (12. 57%) among the selected duration of cold shock studied in experiment 2. The average PVGL was 2.3, 8.6, and 9.3%, respectively, for eggs induced by sperm of bigmouth buffalo, red common carp and grass carp. Average PVGL was significantly lower for eggs induced by sperm of bigmouth buffalo, compared with that for eggs induced by sperm of the other two species. However, average PVGL were similar for eggs induced by sperm of red common carp and grass carp. In summary, the optimal conditions for gynogenesis in tench include the use of irradiated sperm of grass carp to activate the eggs and cold shock of 20 min starting 5 min post activation. Since female tench grow much faster to a larger size than male tench, gynogenesis of tench holds great potential for production enhancement.     

Enzyme treatment for elimination of egg stickiness in tench (Tinca Tinca L.), European catfish (Silurus Glanis L.) and common carp (Cyprinus Carpio L.)

Enzyme treatment to eliminate egg stickiness in tench, European catfish and common carp was compared with standard methodology in an attempt to decrease time consuming under hatchery conditions. Eggs of tench and E. catfish were exposed to an alcalase enzyme MERCK EC 3.4.21.14 (0.6 AU g^?1) solution 3 min after egg fertilization for 2 min. The best enzyme concentration in tench and E. catfish was 10 and 20 ml l^?1 of enzyme, respectively. The eggs of c. carp were successfully destickiness with ALCALASE DX (2.5 AU g^?1) using two concentration of enzyme (2 ml l^?1 and 20 ml l^?1) from 8 to 20 min after fertilization.     

Influence of nutrition on the lipid quality of pond fish: common carp (Cyprinus carpio) and tench (Tinca tinca)

Like marine fish freshwater fish are an important source of essential fatty acids for human nutrition. However, the fatty acid composition of pond fish can vary considerably and strongly depends on that of the ingested food. Investigations on the fatty acid composition of common carp (Cyprinus carpio) and tench (Tinca tinca) have shown that different methods of rearing and feeding cause substantial variations in the proportions of the n-6 and n-3 polyunsaturated fatty acids of these fish species. Carp reared on the basis of natural food in ponds exhibit high contents of n-6 as well as n-3 fatty acids in their muscle triacylglycerols. On the other hand carp fed supplementary wheat in ponds resulted in somewhat lower levels of these essential fatty acids. High amounts of n-3 fatty acids can be found in carp fed high-energy diets containing high levels of fish oil. Analogous results were obtained in experiments with tench reared under different nutritional conditions. While rearing on the basis of only natural food in ponds as well as feeding supplementary wheat yielded in similar levels of n-3 and n-6 polyunsaturated fatty acids, higher contents of n-3 fatty acids were recorded in tench fed pellets. High levels of n-3 polyunsaturated fatty acids in foodstuffs have positive effects on human health. Experiments with different cultured fish species proved that the fatty acid composition of the edible parts can be influenced by the diet. Therefore, a finishing diet with a suitable fatty acid profile can be used to improve the nutritional quality of fish products of farmed origin.     

Proximate and fatty acid composition of 13 important freshwater fish species in central Europe

We aimed to investigate proximate and fatty acid composition of important freshwater fish species in the Czech Republic. Sampled fish include seven species from intensive farming: African catfish, rainbow trout, Wels catfish, Nile tilapia, brook trout, northern whitefish, and pikeperch; eight species from semi-intensive culture systems: common carp, northern pike, pikeperch, grass carp, European perch, tench, silver carp, and catfish; and three species from extensive culture systems: rainbow trout, tench, and common carp. The fat content and fatty acid composition were highly influenced by the culture systems. Simultaneously, we observed a significant dependence of fatty acid composition on the fat content. The content of saturated fatty acids was below 34% in all analyzed fish. Northern pike, pikeperch, and European perch contained with over 50% the highest proportion of polyunsaturated fatty acids. Intensively cultured fish reached the highest content of eicosapentaenoic and docosahexaenoic fatty acid. Nutritional quality was determined by atherogenic and thrombogenic indexes which ranged from 0.27 to 0.63 and 0.20 to 0.61 and by ratios n-3/n-6 (0.54–3.45) and polyunsaturated/saturated fatty acids (0.67–2.01). Results demonstrated that the flesh of all studied species are of high nutritional quality.     

Reciprocal hybrids of tench Tinca tinca (L.) × bream Abramis brama (L.), and tench × carp Cyprinus carpio L., and some characteristics of their early development

Reciprocal hybrids between tench Tinca tinca (L.) and carp Cyprinus carpio L., and tench and bream Abramis brama (L.) were produced artificially. The survival of all these hybrids during embryogenesis was quite high. The highest survival rate (over 60%) at the eyed stage was observed for tench and bream hybrids (both sex combinations). The hatching rates of these hybrids were also over 60%. The number of larvae with some abnormalities (i.e. deformed body) was low. In contrast, the hatching rates of tench and carp hybrids were very low (0.2%). From over 1000 fertilized eggs, only three specimens started swimming, and only one specimen survived to juvenile stage. Embryos of hybrids and their parental species differ in morphological features. These differences were also visible in the juveniles. Body parameters of juvenile hybrids produced from three species had intermediate values in comparison to parental fish.     

Predation as a determinant of size structure in populations of crucian carp (Carassius carassius) and tench (Tinea tinea)

Predation is an important structuring force in many fish assemblages and may have large, direct lethal effects on prey fish populations but also may affect growth rate and survival indirectly through shifts in behavioral patterns. Some species appear more sensitive to predation and earlier studies in a limited set of Finnish ponds suggests that crucian carp (Carassius carassius) is very sensitive to predation, which results in changes in population size-structure and density. In this study we tested the effect of piscivore presence or absence on crucian carp populations by using data from a large number (>600) of Swedish lakes across a wide geographical area and ranging in size from small ponds to large lakes (0.02–4400 ha). We also included a second species, tench (Tinea tinea), in our analyses. The population size structures of crucian carp and tench were clearly related to the presence or absence of piscivores. In lakes and ponds without piscivores. populations were dominated by small-bodied individuals. When piscivores were present, populations consisted almost exclusively of large individuals. Densities of crucian carp and tench were much higher in ponds and lakes without piscivores. There were no differences in size structure or relative abundance when catches from electrofishing were compared with gill net catches, suggesting that our results are not an effect of a behavioral shift in the presence of piscivores.     

Potential vector species of carp edema virus (CEV)

During a PCR‐based CEV survey in Poland in 2015–2017, the virus was detected in many farms both in clinical and asymptomatic cases and in common as well as in koi carp (Cyprinus carpio). In order to evaluate the potential carrier role of fish species that share the same habitats with carp, an experimental trial was performed. Investigations carried out on specimens of bleak (Alburnus alburnus), crucian carp (Carassius carassius), European perch (Perca fluviatilis), Prussian carp (Carassius gibelio), roach (Rutilus rutilus) and tench (Tinca tinca) cohabited with CEV‐infected carp yielded positive results. These species of fish were experimentally cohabited with CEV‐infected common carp at a temperature of 16°C ± 1. Material from the brain, gills, spleen, kidneys, intestine and skin was investigated for the presence of CEV DNA. Similar investigations were performed with uninfected fish designated controls. Samples were tested for CEV by qPCR.     

Fish population estimation: the use of rotenone to evaluate the reliability of a removal technique

Abstract. The use of a large-meshed seine net (aperture 2–5 cm) in enclosed compounds was an effective method for the capture of large grass carp, Ctenopha-ryngodon idella (Val.), and tench, Tinea tinea L., with mean fork lengths of 42–9 cm and 38–3 cm and mean weights of 1–53 kg and 1–10 kg respectively. Calculated population estimates using a constant-effort removal technique showed a high degree of accuracy for grass carp, when the absolute index of population size was checked after completion of netting with an application of a commercially available rotenone formulation. It is suggested that this was so because of the large proportion (>90%) of the total population netted. Large tench may be unsusceptible to rotenone at the low concentration of 0–5 ppm used, so no check on the accuracy of the population estimation was possible.     

Khawia sinensis Hsü, 1935 (Cestoda: Caryophyllidea), a tapeworm new to the British Isles: a threat to carp fisheries?

Abstract Khawia sinensis Hsü is recorded for the first time from the British Isles. K. sinensis was recovered from many naturally infected common carp, Cyprinus carpio L., and one tench, Tinca tinca (L.) in 18 localities in England. Prevalence ranged from 4.5 to 100% and intensity of infection from one to 51 worms per fish. The worms were identified as Lytocestidae by the medullary arrangement of the vitelline glands and the cortical position of the testes, and as K. sinensis on scolex characteristics and detailed arrangement and measurements of genital organs. No evidence of pathogenicity was observed, although K. sinensis has been reported as a serious pathogen of cyprinids in overseas fisheries. The potential threat of this tapeworm to carp fisheries in England is discussed.     

Introduced and translocated fish species in the inland waters of Greece

Over the last 7 decades, 23 exotic fish species have been introduced into the inland waters of Greece. Some introductions were deliberately planned to take advantage of particular ecological or economic qualities of the species concerned. These include rainbow trout, Oncorhynchus mykiss (Walbaum), Pacific salmon, Oncorhynchus sp., vendace, Coregonus lavaretus (L.), grass carp, Ctenopharyngodon idella (Valenciennes), and silver carp, Hypophthalmichthys molitrix (Valenciennes). Other introductions, such as that of pumpkinseed, Lepomis gibbosus (L.), and false rasbora, Pseudorasbora parva (Temminck & Schlegel), were unintentional. Further transfers were made of species between various basins within the country, including common carp, Cyprinus carpio L., tench, Tinca tinca (L.), crucian carp, Carassius auratus gibelio (Bloch), bitterling, Rhodeus amarus (Bloch), and Aristotle's catfish, Silurus aristotelis Garman. Some species have become fully acclimatized and have built up important populations. In other cases, the transfers and introductions have had considerable negative impacts, particularly where introduced species have outcompeted native forms, as in the cases of the mosquito fish, Gambusia affinis (Baird & Girard), versus Greek toothcarp, Valencia letourneuxi (Sauvage), in the western Greek marshes, and of Aristotle's catfish versus the wels, Silurus glanis L., in Lake Volvi.     

Freshwater Fish Burgers Made from Four Different Fish Species as a Valuable Strategy Appreciated by Consumers for Introducing EPA and DHA into a Human Diet

The nutritional profile and the consumer preference of fish burgers made from carp, goldfish, perch, and tench were investigated. Perch and goldfish burgers, which have the highest proportion of eicosapentaenoic acid (6.63% and 4.90%, respectively) and docosahexaenoic acid (20.28% and 11.99%, respectively), showed lower absolute amounts of these fatty acids (17.03 and 10.10 mg/100 g food, respectively) than tench and carp (31.16 and 49.63 mg/100 g food, respectively). The consumer evaluation established that differences in the perception of the fish burgers exist. The overall liking and taste were the main attributes that influenced both consumer’s acceptance and purchase intent.     

Survival and growth of larval and juvenile tench, Tinca tinca L., fed different diets under controlled conditions

Abstract. Tench, Tinca tinca L., larvae were reared under controlled conditions at water temperatures of 28°C and 31°C during a 15-day period. Feeding with exclusively live Artemia nauplii gave best results, irrespective of rearing temperature (total length 13·6mm; average weight 31 mg; survival rate 83–85%). High survival rates of 81–88% were found also in all groups fed mixed diets, whereas growth rate of tench larvae was significantly influenced by the frequency of supplemental feeding with Artemia. When applied alone, the tested carp starter feed turned out to be insufficient for rearing the larval tench.     

Assessment of diet in two cyprinids using a modified stomach-flushing technique

Abstract. A modified flushing technique was used to sample the anterior gut contents of the stomachless cyprinids, the tench, Tinea tinea (L.), and grass carp, Ctenopharyngodon idella Val., in the laboratory and the field. The method was developed to provide quantitative estimates by measuring optimum penelration of a catheter into the gut of tench from their fork length. Possible implications for the sampling of gut contents of other cyprinids are discussed.     

Response of juvenile tench (Tinca tinca L.) fed practical diets with different protein contents and substitution levels of fish meal by soybean meal

A basal practical diet for juvenile tench (Tinca tinca) was formulated and elaborated to test several protein contents and substitution possibilities of fish meal (FM) by soybean meal (SBM) in a 90‐day trial with 5‐month‐old juveniles (30.54 mm TL, 0.30 g W). A factorial design included nine feeding treatments: three protein contents (50%, 40% or 30%) and three levels of replacement (0%, 25% or 45%) of FM protein by SBM protein. In addition, a commercial carp feed was used as reference. Final survival ranged from 98.2% to 99.4%. The 50% dietary protein with 0% or 25% replacement and 40% dietary protein with 25% replacement diets enabled higher growth (P < 0.05) and lower FCR (P < 0.05) than the rest of practical diets. Fish fed 50% dietary protein had similar growth than those fed carp feed (63.8% protein). Deformed fish averaged 1% for the practical diets and 87.6% for the carp feed. The basal practical diet has showed to be feasible and levels of 40–50% dietary protein with 25% replacement of FM protein by SBM protein can be recommended for juvenile tench aged 5–8 months.     

Comparative study of digestive enzymes in fish with different nutritional habits. Proteolytic and amylase activities

This work provides a comparative study of the proteolytic and amylase activities in six species of fish with different nutritional habits: rainbow trout (Oncorhynchus mykiss), gilthead seabream (Sparus aurata), European eel (Anguilla anguilla), common carp (Cyprinus carpio), goldfish (Carassius auratus), and tench (Tinca tinca). Trout and carp showed the highest digestive proteolytic activity. When proteolytic activity was determined in a wide range of pHs, the highest values in the digestive tract of all species were found at alkaline pHs, except in eel where activity could be detected only at acid pHs. Eel showed the lowest digestive proteolytic potential among all the species studied. With respect to amylase activity, the omnivorous species presented higher activity than did the carnivores. Among the carnivorous species, the lowest activity was found in trout. The ratio of total amylase:total proteolytic activity was higher in omnivorous fish species, the carp having the greatest value, whereas in trout this ratio was lower than one. Digestive enzyme activity declined as the incubation temperature decreased, but this trend varied depending on the fish species and the tissue analyzed.     

Carp edema virus from three genogroups is present in common carp in Hungary

Hungary is an important carp producer with intensive trading relationships with farms in other carp‐producing areas in Europe. Carp in Europe were recently found infected with carp edema virus (CEV), a poxvirus which causes the koi sleepy disease (KSD) syndrome. Moribund carp were collected from 17 fish farms and angling ponds in different regions of Hungary. Histological analysis of gills from these carp revealed a proliferation of the interlamellar epithelium and an infiltration by eosinophilic cells. In 13 of 17 of these carp, CEV DNA was detected by qPCR and in seven fish more than 1 × 10⁴ copies of virus‐specific DNA sequences per 250 ng of DNA, which could be considered as clinically relevant and a cause of disease. A phylogenetic analysis of the sequences revealed that all three genogroups of CEV were present in Hungarian common carp with genogroup I being most abundant. These results support the hypothesis of a prolonged presence of CEV in European carp populations and suggest that previous outbreaks of KSD were not recorded or misdiagnosed. Hence, a testing of carp and koi for infection with CEV should be included into disease surveillance programmes to prevent further spreading of this disease.     

Edwardsiellosis in farmed rainbow trout (Oncorhynchus mykiss)

Edwardsiella tarda was isolated from naturally infected rainbow trout (Oncorhynchus mykiss) in raceway culture on a commercial fish farm where the fish were kept at a density of 110 kg m^?3 and at a water temperature of 14°C and with a photoperiod of 13 h light:11 h dark. The clinical signs of diseased fish (150 ± 20 mm standard length) were anorexia and lethargy. The most striking lesions in the fish were in the liver. There were hyperaemia and haemorrhages; on histopathological examination, the liver displayed inflammatory infiltrate in portal area, focal necrosis, dilatation of blood sinus and activation of sinusoidal cells. Infection experiments, performed 2 years after isolation of the original culture of E. tarda, were carried out under laboratory conditions at water temperatures of 15, 18 or 24°C. All experimental fish (common carp, Prussian carp, tench), intraperitoneally injected with 8 × 10⁶ cells, demonstrated a total resistance to E. tarda.     

Genetic and structural characterization of the growth hormone gene and protein from tench, Tinca tinca

The analysis of the tench growth hormone gene structure revealed a comparable organization of coding and non-coding regions than other from cyprinid species. Based on the performed mRNA and amino acid sequence alignments, gh tench is related to Asian than to European representatives of Cyprinidae family. Second aim of the work was to characterize and predict protein structure of the tench growth hormone. Tinca tinca GH share many common features with human GH molecule. The Tench GH protein binds to the growth hormone receptor (GHR) using two regions I and II that are situated at opposite sites of molecule. Binding site I is placed in the central part of T. tinca GH and H 189 amino acid in the middle region of the IV helix is crucial for GH–GHR interactions.     

Comparative growth and diet of tench Tinca tinca (L.) larvae and juveniles from river floodplain biotopes in France and England

The growth and diet of larvae and 0 + juveniles of riverine tench Tinca tinca (L.) were compared in two stagnant floodplain biotopes from the upper River Rhône, France, and the River Great Ouse, England. The diet of tench was generally similar at the French and English sites, with Cladocera being the predominant prey of young larvae (English site only). Cladocera and Copepoda were the principal prey of older larvae and 0 + juveniles, though the latter took a variety of other, larger prey items. Ontogenetic changes in diet at both sites probably reflect prey availability. Protracted spawning at the French site contrasted a single spawning effort in the English backwater. Fluctuations in growth rate and condition were observed to coincide with shifts in diet, suggesting that tench developing in riverine biotopes may be vulnerable to competition at particular transitional intervals in their early ontogeny.     

Artificial spawning of common tench <Emphasis Type="Italic">Tinca tinca</Emphasis> (Linnaeus, 1758), obtained from wild and domestic stocks

The study encompasses three reproduction seasons. Tench spawners caught during the spawning season originated from carp ponds (domestic stock) and a lake (wild stock). Fish were reproduced under controlled conditions after hormonal stimulation with GnRHa-containing pellets combined with metoclopramide (Ovopel) or carp pituitary homogenate (CPH). As a result of hormonal stimulation, eggs were obtained from a larger number of females originating from the lake (71.7%) than those originating from the pond (58.3%), although no other statistical differences were found. A similar relationship was recorded for the spermatozoa motilities (range from 72 to 76%). The obtained results indicate that both investigated reservoirs are suitable for tench broodstock management due to the fact that synchronization of ovulation among different stocks is easy to achieve. For this purpose, among the tested spawning agents, Ovopel could be recommended as being slightly more effective.