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Tinca Tinca L. (tinca + tinca_l)
Selected AbstractsSuccessful gonadal development and maturation of tench (Tinca tinca L.) in small concrete pondsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2003J. M. Carral Summary The experiments were performed in a tench farm from autumn until the spawning season (June,July). Tench broodstocks from natural habitats were maintained in 25 × 6 × 1 m concrete ponds and fed on commercial trout pellets. Females and males were separated and maintained under natural photoperiod and temperature conditions at densities around 2 kg m,2. Water flow throughout was supplied at the rate of 15 L s,1. When females showed external signs of advanced gonadal development, induction of spawning was made by luteinizing hormone releasing factor (LH-RH) synthetic analogue administration at three different periods of the reproductive season (June,July). A single intramuscular injection (20 ,g kg,1 body weight) was administered to 110 mature females selected from a total of 150. The females were stripped 42 h (22°C) after hormone administration. The mean rate of stripped females to the number injected was 77%. Mean relative egg weight in relation to the weight of the stripped females was 5.61%. More than 90% of the males provided semen without hormonal induction. Differences in egg production and external egg quality were observed at different times of the spawning period. It was proven that tench maintained in small concrete tanks and fed on artificial diets were able to reach gonadal maturation. [source] Food competition between 2+ tench (Tinca tinca L.), common carp (Cyprinus carpio L.) and bigmouth buffalo (Ictiobus cyprinellus Val.) in pond polycultureJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2003Z. Adámek Summary Natural diets of tench (Tinca tinca L.), carp (Cyprinus carpio L.) and bigmouth buffalo (Ictiobus cyprinellus Val.) were studied to determine food competition among them in polyculture stocks of two different densities. Tench diet consisted mainly of zooplankton (43.8%) and bottom sediments (21.2%). In contrast, carp diet consisted mainly of bottom items including plant debris and detritus (68.8%), which dominated over zooplankton (19.1%). In bigmouth buffalo, most food bulk comprised zooplankton (80.7%). Thus, the resulting food competition (i.e. similarity) was most pronounced between tench and carp (60.8%) and between tench and bigmouth buffalo (47.4%). When comparing growth performance of the three cultured species, the ratios between stocking and harvesting size were: in normal stocking density (392 kg ha,1) 1.72, 3.67 and 2.13, and in doubled stocking density (777 kg ha,1) 1.07, 2.33 and 2.16 in tench, carp and bigmouth buffalo, respectively. [source] The haematology of gynogenic tench, Tinca tinca L., and of recessively homozygous colour tench strainsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2003M. Flaj Summary Two wild-coloured strains of tench (the first meiotic gynogenic generation MeiG1, and their control diploid half siblings) and three recessively homozygous colour strains (golden, blue and alampic) were examined for the determination of basic haematological indices. The MeiG1 strain had higher erythrocyte counts than diploid controls or the blue and alampic strains (P < 0.001), and had a higher blood haemoglobin content than all three colour strains (P < 0.001). No differences were detected among strains for haematocrit, mean corpuscular haemoglobin, or mean corpuscular volume. Both the lowest leucocyte count (P < 0.001) and leucocrit value (P < 0.001) were found in the alampic tench, and may result from a negative pleiotropic effect of this recessive homozygous genotype (bbgg). In agreement with previous findings in tench, the differential leucocyte count revealed lymphocytes to be the dominating white blood cells; their rate was about 90% in both the wild-coloured and blue strains, and less in the other two strains (83,84%). Neutrophil granulocytes were most abundant in the MeiG1 strain. Eosinophil granulocytes were detected only in the golden strain, and were not common (0.2%). [source] Influence of dietary composition on growth and energy reserves in tench (Tinca tinca)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2001N. De Pedro The effects of different protein, lipid and carbohydrate diets on growth and energy storage in tench, Tinca tinca L., were studied. Over a 2-month period fish were fed four different diets: control, protein-enriched, carbohydrate-enriched and lipid-enriched. The best growth rates were obtained with the control and protein-enriched diets; the carbohydrate diet produced the worst results (lowest specific growth rate, weight gain, nutritional index and hepatosomatic index). These results suggest that it is not advisable to reduce dietary fish protein below 35%, and that it is not possible to obtain a protein-sparing effect of either lipids or carbohydrates, at least in our experimental conditions. The high-protein diet resulted in the storage of energy excess as muscle proteins and hepatic glycogen. Tench fed the high-carbohydrate diet stored carbohydrates as muscle glycogen and reduced plasma triglycerides. Finally, both liver and muscle lipid content were in positive correlation to dietary lipid. [source] Morphological sex change upon treatment by endocrine modulators in meiogynogenetic tench (Tinca tinca L.)AQUACULTURE RESEARCH, Issue 2 2010Martin Hulak Abstract Exogenous steroids alter sex differentiation in fish substantially. In the present study we have evaluated the effects of 17,-methyltestosterone (MT) and oestrogen receptor antagonist Tamoxifen (TA) on gonadal development and skewness of the sex ratio in all-female tench juveniles. In the first two experiments, sexually undifferentiated juveniles were orally treated with three doses of MT and TA (50, 100 and 150 mg kg,1). Both the treatments resulted in a moderate dose-dependent masculinization, with neomale production ranging from 17% (50 mg kg,1) to 26% (150 mg kg,1) for the MT only treatment, and from 0% (50 mg kg,1) to 27% (100 mg kg,1) only for the TA treatment respectively. In the third experiment treatment of sexually differentiated tench females with single steroid treatments or combinations of the two resulted in populations composed of females and intersex individuals. The significantly highest occurrence of intersex individuals (45.5%) was found in the group subjected to combine treatment of MT+TA (150+200 mg kg,1). No masculinization effect of the single or the combined treatment occurred. It can be concluded that oral treatment with MT or TA only slightly modifies the normal process of sex differentiation in gynogenetic tench juvenile, but treatment with the above-mentioned combinations has a highly significant potential to skew the sex ratio in sexually differentiated tench females. However, from an applied point of view, the treatment procedure will need optimization before use at a commercial level. [source] Effects of four egg desticking procedures on hatching rate and further survival and growth of larvae in the tench (Tinca tinca L.)AQUACULTURE RESEARCH, Issue 6 2006Jose M Carral Abstract Four desticking procedures for tench eggs (A: tannic acid solution (1 g L,1) for 15 s; B: alcalase enzyme solution (8 mL L,1) for 60 s; C: alcalase enzyme solution (15 mL L,1) for 120 s; D: Woynarovich and Woynarovich (1980) solution for 58 min followed by tannic acid solution (1 g L,1) for 15 s) were tested to obtain data about influence on embryo survival to hatching stage and further survival and growth of the larvae. In the tannic acid and Woynarovich and Woynarovich (1980) treatment (A and D) few eggs stuck together and some were adhered to the incubator walls, whereas in the alcalase treatments (B and C) eggs neither stuck together nor adhered to the incubator walls. Percentages of hatched larvae did not show significant differences (mean values ranged between 47.4% in treatment A to 37.0% in treatment C). Larvae deformities observed were <0.5% in all cases. There were no significant differences among survival and growth rates of the larvae from different egg desticking origin, reaching, after 30 days, mean survival values around 90% and total length and weight of 12.5 mm and 19 mg respectively. [source] | ||||||||||