Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 30

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The results of stages in controlled reproduction of African catfish C. gariepinus were investigated in females in six classes of body weight (I: >0 ≤1.5 kg; II: >1.5 kg ≤2.5 kg; III: >2.5 kg ≤3.5 kg; IV: >3.5 kg ≤4.5 kg; V: >4.5 kg ≤6.5 kg; VI: >6.5 kg), their ovulation being stimulated with Ovopel (1 pellet kg–1). The accepted classification significantly (P≤0.01) differentiated the weight of obtained eggs expressed both in grams and in percentage of female body weight. The highest weight of eggs was obtained from the heaviest fish (class VI) and the lowest from these of the lowest weight (class I) (1191.8 g and 218.7 g respectively) while in these two classes the obtained highest weight of eggs was expressed as the percentage of female body weight (14.21% and 20.19% respectively). The class of body weight significantly (P≤0.01) determined also the two investigated traits which described the quality of eggs. The lowest value of the least squares means for the percentage of fertilization and of live embryos was noted for the heaviest fish (class VI) (64.75% and 54.63% respectively) and the highest for the fish of the lowest weight, i.e., classes I and II (91.67% and 88.17%, 92.47% and 86.33%). In general the highest effectiveness of reproduction characterized the class of females whose body weight exceeded 4.5 kg but did not rise above 6.5 kg. In order to predict the weight of eggs [g], percentage of fertilization [12 h] and percentage of live embryos [24 h] within the investigated classes the regression equation was introduced using the weight of females as an independent variable. For each class regression equations were also derived in which the weight of females and weight of eggs were accepted as independent variables while the percentages of fertilization and of live embryos were used as dependent variables. The value of empirical data concerning the weight of eggs [g], fertilization percentage [12 h] and percentage of live embryos [24 h] were the basis for deriving a square function which permitted spatial prediction of the distribution of points of these variables on a plane – for each class of female body weight separately.
The effects on reproduction were investigated in carp of the Hungarian strain 0 and the Yugoslavian strain J after CPH or Ovopel tratment. After hypophysation eggs were obtained from a similar percentage (~85%) of fish in both strains while after the Ovopel treatment from 100% of females in strain 0 and 50% in strain J. Interaction between the preparation and the provenance of the fish was statistically significant (P ≤ 0.05) for the weight of eggs (in grams and in percentage of female body weight). The highest weight of eggs was obtained after Ovopel treatment of females of strain J and the lowest after CPH application to fish of the same strain (1042.98 g, 15.60% and 746.49 g, 10.97%, respectively). The statistical significance (P ≤ 0.01) of the interaction was noted too for the fertilization percentage; the lowest quality characterized eggs obtained from females of strain J treated with CPH and the highest for eggs of the same strain treated with Ovopel (95.80% and 98.20%, respectively). The effect of latency as an important factor of quality of the eggs obtained after ovulation induction with CPH and with Ovopel from females of the strain 0 was determined. The comparison of reproduction effects of the investigated breeding strains of carp showed that these strains differently respond to the ovulation stimulators applied.
Effects on the reproduction of C. gariepinus after ovulation stimulation with carp pituitary homogenate (CPH), Ovopel or Dagin were investigated. After the application of Ovopel all the females spawned while after CPH or Dagin treatment spawning was reduced to 83.3%. No statistically significant effect of the stimulator was found on the weight of eggs expressed in g and in % of female B.W. however, the highest mean values of these parameters were found after Dagin. A statistically significant effect of the stimulator was noted for the percentage of fertilization and living embryos after 24h and 28h incubation. The highest percentage of live embryos after a 28h incubation of eggs was found after the treatment with Dagin and the lowest after Ovopel; the difference between the means of these stimulators was statistically significant. The females ovulated 12h after Ovopel treatment yielded eggs of a higher weight and of significantly higher quality compared with those obtained 3h later. The relative effectiveness of reproduction, expressed as the number of live embryos per kg of female B.W., was highest after Dagin treatment.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.