Growth Performance of All-Female and Mixed-Sex Common Carp Cyprinus Carpio L. Populations in the Central Europe Climatic Conditions

The results of a 4-yr study focused on comparing growth performance in all-female and mixed-sex populations of common carp are presented. All-female and mixed-sex populations of purebred Northern mirror carp (M72) and scaly crossbreds of female Ropsha (ROP) and male/neomale M72 carp (ROP × M72) were used for this experiment. Average weight and survival after each growing season and slaughtering value after the third and fourth year of the study were measured. While after 8 wk of rearing no differences between all-female and mixed-sex populations were found, the 1-yr-old all-female mirror carp population (M72) gained 29.7% more weight ( P < 0.0001) than the mixed-sex (68.5:± 15.8 g against 52.8:± 13.9 g; meant S.D.) population. After the second, third and fourth year of rearing, live weight was 9.5% ( P = 0.0062) and 6.8% ( P = 0.0229) and insignificantly 5.1 % higher, respectively, in the all-female population. There was no significant difference, even after the fourth growing season, in live weight between all-females and bisexual scaly crossbreds (2,192 g± 478.3 and 2,206 g± 484.5, respectively). The percentage of the main edible parts (processed body, filleting yield) was significantly higher in both mirror and scaly, all-female populations at 3 yr of age but not significantly different in 4-yr-old fish. No distinct differences in survival and body shape of all-female and bisexual populations were found. The potential of all-female populations for commercial production is discussed.     

The role of Ca2+ and Na+ membrane transport in brook trout (Salvelinus fontinalis) spermatozoa motility

The role of environmental ion composition and osmolality in Ca²⁺ signaled activation was assessed in spermatozoa of brook trout Salvelinus fontinalis. Milt from ten mature males was obtained by abdominal massage. Spermatozoa motility was evaluated in 0, 100, and 300 mOsm/kg NaCl or sucrose solutions, buffered by 10 mM Tris–HCl pH 8.5. For investigation of spermatozoa reaction to external Ca²⁺ concentration, 2 mM ethylene glycol tetraacetic acid (EGTA) was added to the activation media as a calcium ions chelator. For investigation of the effect of external Na⁺ concentration in conditions of low external Ca²⁺, 100 µM amiloride was added to the EGTA-containing solutions as a Na⁺ transport blocker. Low motility was observed in sucrose (Na⁺ free) solutions containing 2 mM EGTA but not in Na⁺ solutions containing 2 mM EGTA. Addition of amiloride led to significantly increased motility (P < 0.05) compared with sucrose (Na⁺ free) solutions containing 2 mM EGTA. We conclude that Na⁺ transport in Ca²⁺-free solutions plays a regulatory role in brook trout spermatozoa activation. The influence of competitive Na⁺ and Ca²⁺ transport on the control of spermatozoa activation requires further study with respect to its application for improvement of artificial activation and storage media.     

Protection of common carp (Cyprinus carpio L.) spermatozoa motility under oxidative stress by antioxidants and seminal plasma

The protective influence of seminal plasma and the antioxidants catalase (CAT), superoxide dismutase (SOD), and glutathione (GTH) on quality parameters, oxidative stress indices, and antioxidant activity was studied in common carp (Cyprinus carpio) spermatozoa exposed to the xanthine–xanthine oxidase (X–XO) system. Fish spermatozoa were incubated for 5 and 20 min at 4 °C with X–XO concentrations of 1 mM X–0.1 U/mL, 0.6 mM X–0.05 U/mL, 0.3 mM X–0.025 U/mL, and 0.1 mM X–0.0125 U/mL. A dose-dependent reduction in spermatozoa motility and velocity was observed at concentrations of 0.1 mM X–0.0125 U/mL to 1 mM X–0.1 U/mL XO. Increase in spermatozoa motility parameters was recorded following treatment with antioxidants and seminal plasma. The level of the oxidative stress indices lipid peroxidation (LPO) and carbonyl derivatives of proteins (CP) was significantly reduced after addition of CAT, SOD, or GTH along with seminal plasma. Significant differences in SOD, glutathione reductase, and glutathione peroxidase activity were seen in spermatozoa incubated with, compared to that without, seminal plasma at all studied X–XO concentrations. The data demonstrated that CAT, SOD, or GTH in combination with SP can reduce reactive oxygen species stress in fish spermatozoa and improve spermatozoa quality.     

Protective role of antifreeze proteins on sterlet (<Emphasis Type="Italic">Acipenser ruthenus</Emphasis>) sperm during cryopreservation

The loss of sperm quality in sterlet (Acipenser ruthenus) due to freeze-thaw process in cryopreservation was investigated in the present study. Two antifreeze proteins (AFPI or AFPIII) were used at different concentrations of 0.1, 1, 10, and 100 μg/mL. We compared motility, curvilinear velocity, and plasma membrane integrity of fresh, cryopreserved sperm, and sperm cryopreserved in the presence of antifreeze proteins. Fresh sperm (control) had 85?±?4% motility and 160?±?2 μm/s curvilinear velocity, respectively. After cryopreservation, the motility of frozen-thawed sperm without addition of antifreeze proteins significantly decreased (44?±?9%), compared to the control. The highest motility of frozen-thawed sperm was obtained in cryopreserved sperm with addition of 1 μg/mL of AFPIII (58?±?14%). No significant differences were observed in curvilinear velocity between fresh sperm and cryopreserved sperm with/without addition of AFPI or AFPIII. The flow cytometry analysis revealed that fresh sperm contained 94.5?±?6% live cells, while the cryopreserved sperm only contained 26.6?±?14% live cells. Supplementation of antifreeze proteins has significantly improved the percentage of live cells in frozen-thawed sperm, except 0.1 μg/ml of AFPI group. No significant difference in percentage of live cells was detected in the sperm cryopreserved with 10 μg/mL of AFPI or AFPIII, compared to fresh sperm. Thus, addition of antifreeze proteins to cryopreservation medium could be considered to improve the post-thawed sperm quality of sterlet.     

Comparative measurements on ruminal pH-value in cattle

Subacute rumen acidosis (SARA) of ruminants is an important factor in terms of animal health, especially in high yielding cattle. In order to find an accurate method to determine the ruminal pH-value, three methods using eight rumen cannulated cattle were compared. An indwelling measuring unit (sensor) was used for continuous measurement of the ruminal pH-value. These results were compared to the pH-values of samplings via rumen fistula and to the results of samplings via oral stomach tube. Due to the different rations, mean pH-value of trial 1 (average of all methods) was 6.64 +/- 0.37 (hay ad lib., 2 kg concentrate/ animal) and 6.24 +/- 0.36 for trial 2 (75% maize silage, 1 kg hay, 2 kg soybean meal). In trial 1 no statistically significant differences between all methods could be observed. Under more acidic ruminal conditions of trial 2 all methods differed significantly (p < 0.05). In the lower pH-range of trial 2, a difference of 0.32 that data can be collected continuously. The sensor system was evaluated by a comparison with standardized pH-dilutions (pH 4, pH 7). The sensor system has proven to be an accurate and reliable instrument (r = 0.9984) and it represents an innovative system for answering scientific questions in terms of rumen physiology and rumen pathology.     

Preliminary Studies on Cryopreservation of Common Tench (Tinca tinca) Embryos (Work in Progress)

Vitrification could provide a promising tool for the cryopreservation of fish embryos. However, to achieve cryopreservation using vitrification, chilling sensitivity and cryoprotectants toxicity were determined using tench embryos at four developmental stages (11, 17, 23 and 29 h). Embryos treated with alcalase (2 ml/998 ml, 2 min at 22°C) were exposed to chilling with/without warming. Other embryos were exposed to methanol and glycerol at the concentration of 10% and 20% for periods of 20 min. At last, embryos were incubated at special incubator cages where hatching rates were counted. Regarding chilling sensitivity and exposure to chilling followed by warming, the hatching rates of embryos decreased significantly (p < 0.001) after exposure to 0°C at all developmental stages except the 29-h stage compared with the controls. The embryo stage most sensitive to chilling was 11-h stage. The 29-h stage exhibited the least sensitivity to low temperature while 17-h and 23-h stages were intermediate in their sensitivity to chilling. The toxicity of methanol increased significantly (p < 0.001) with developmental stage for 11, 17 and 23-h stages. The highest hatching rates of tench embryos were obtained with 29-h embryos using various concentrations of methanol. The hatching rates of tench embryos exposed to glycerol concentrations were approximately similar to those embryos exposed to methanol concentrations except for 11-h embryos that showed no hatching. Unfortunately, we could not obtain living embryos in any of the conditions examined after vitrification. In conclusion, it was quite difficult to vitrify the tench embryos during this study using various vitrifying solutions and the method reported by Chen & Tian (2005) and further studies are needed to achieve successful cryopreservation.     

Evaluation of the therapeutic efficacy of rumen transfaunation

Transfaunation is supposed to stimulate normal rumen function and has been used as an ancillary treatment for indigestion. Although it is widely recommended, there are little research data on the efficacy and the necessary volume. The objective of the prospective clinical trial was the evaluation of the therapeutic efficacy of two different transfaunation volumes which can be obtained under practical conditions. Forty-five cattle suffering from indigestion were included in the study. A scoring system for the classification of rumen fluid was used. Scores were given in accordance with the importance of the parameter as an indication of microbial dysfunction. Animals with disturbed rumen fluid composition and activity were randomly assigned into 3 groups. Group 1 received 1 L of rumen fluid, group 2 received 5 L of rumen fluid and group 3 (control group) received 5 L of body temperature water. Rumen fluid analysis was repeated on days 1 and 4 after transfaunation. The feed intake of the animals was recorded. After the transfaunation of 1 L and 5 L, the rumen fluid score improved significantly from day 0 to days 1 and 4. Rumen fluid samples in the control group showed no significant improvement from day 0 to day 1. No significant differences were observed between the two treatment groups. But significant differences between the improvement of group 1 and the control group on days 1 and 4 and significant differences between group 2 and the control group on day 1 were detected. Small volumes of rumen fluid are easily obtainable by stomach tubes fitted with suction pumps. In summary, the transfaunation of as little as 1 L of rumen fluid caused significant improvement in the activity of rumen flora in cows suffering from indigestion.     

Testing of performance in common carp Cyprinus carpio L. under pond husbandry conditions I: top-crossing with Northern mirror carp

Performance tests of Northern mirror carp (M72) and three different crossbreds were conducted in semi‐intensive pond conditions from the larval stage up to market size. The aim of this study was to evaluate the possible utilization of new hybrid combinations (M72 × PL – Poho?elice mirror carp) and (M72 × Dor – Israeli mirror carp), and to compare them with a hybrid widely reared as a commercial product (M72 × M2 – Hungarian mirror carp) and with M72 purebred. The testing model was derived from similar studies carried out in the conditions of the Czech Republic, where an internal control of different scale cover is used to eliminate all non‐genetic effects. ancova revealed at market size significantly better growth in M72 × Dor (1 619±28.3 g; LS mean±SE) and M72 × PL (1475±29.8 g) compared with M72 (1278±26.3 g). Survival during the test of 3 years duration was significantly the best in the M72 × Dor hybrid as were the dressing out parameters measured at market size, even if these were significantly different only in proportion of fillets with skin (39.1±0.28%). Interestingly, the crossbred M72 × M2 commonly used by Czech fishermen showed for both, growth (1371±26.2 g) and survival, the lowest values among crossbreds and with regard to dressing out parameters mostly among all tested groups.     

Studies on sperm of diploid and triploid tench, Tinca tinca (L.)

The tench Tinca tinca is an interesting fish from the viewpoint of polyploidy and related atypical reproduction aspects. Triploid tench were produced artificially. Studies of spermiation as well as of sperm motility and structure were performed on several triploid and diploid males simultaneously with individual experimental crosses with diploid females to define their reproductive capacities. The testes of triploids visually looked less developed in the most of cases with lower sperm production (0.05 cm³ sperm per male), GSI and weight of testes compared to diploids (0.58 cm³ sperm per male). Analysis of variance showed significant influence of ploidy level on the percentage of motile spermatozoa. Triploidy did not change percentage of live spermatozoa and velocity of spermatozoa at the first time of sperm movement. The study of sperm structure by scanning electron microscopy revealed that most sperm cells were of normal structure with some anomalies. Sperm heads of triploid and diploid males were mostly round-shaped, 1.86±0.2 and 1.6±0.18 μm in diameter. The midpiece of triploid spermatozoa was slightly narrower than that of diploid ones with typical cylindrical shape. Flow cytometry revealed sperm cells of triploids to be largely aneuploid (1.47 n) with high mosaic DNA, oscillating from haploid DNA content (1.0 n) to diploid DNA content (1.9 n). Experimental crosses between triploid males and diploid females revealed that these males were capable to stimulate effective development with relatively high level of fertilization and hatching rates from 0 to 70%. In conclusion, triploidization does not seem to guarantee sterility of tench.