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1

Cyclic development of sex cells in artificially bred rudd Scardinius erythrophthalmus [L.]

100%
Kopiejewska W., Terlecki J., Chybowski L.
Acta Scientiarum Polonorum. Piscaria
|
2004
|
tom 03
|
nr 1-2
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Reproduction biology of Helix aspersa under farm conditions

84%
Mach-Paluszkiewicz Z.
Folia Malacologica
|
1999
|
tom 07
|
nr 4
3

Effect of papain and piperonyl butoxide/MGK-264 on the reproduction/development of Lymnaea acuminata

84%
Hanif F., Singh D. K.
Journal of Biology and Earth Sciences
|
2013
|
tom 03
|
nr 1
4

Reproductive biology of the endangered percid Zingel asper in captivity: a histological description of the male reproductive cycle

84%
Chevalier C., de Conto C., Exbrayat J.-M.
Folia Histochemica et Cytobiologica
|
2011
|
tom 49
|
nr 3
5

Sexual maturity and productivity response of pullets fed varying energy levels in The Tropics

84%
Adeyemo A. I., Longe O. G.
Roczniki Naukowe Zootechniki
|
2000
|
tom 27
|
nr 4
6

Reproductive cycle of Arvicola sapidus (Rodentia, Arvicolidae) from southern Navarre, Spain

84%
Garde J. M., Escala M. C.
Acta Theriologica
|
1996
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tom 41
|
nr 4
Development of sexual maturity and reproductive activity in Arvicola sapidus Miller, 1908, was studied. The sample analyzed consisted of 374 specimens (208 males and 166 females), captured in various localities in southern Navarre (Spain). Maturity and sexual activity of the males were evaluated both from the cytological analysis of testicular and epididymal tissues and by the testicular and vesicular size. Maturity and sexual activity of the females were determined as a function of the vulva condition, size and vascularization of the uterus, presence of embryos and placental scars, histological analysis of the ovary and development of the mammary glands. The results show that sexual maturity development is related to age, season and size of both the individual and its reproductive organs. In the studied population there are males with spermatozoa present throughout the entire year. However, the size of testes and seminal vesicles of the adult males varied yearly, reaching lowest values at the end of autumn and winter. The mean number of embryos per litter is 3.7 ± 1.4 (ft = 51, range; 1-7), being closely related to the mother's weight. Intrauterine mortality affects at leats 5.1% of the embryos and 17.6% of the litters, while 53.7% of the females show placental scars. Females show high sexual activity between March and October (46.1-90.0% are pregnant or nursing) and are less active in the remaining months. In southern Navarre, A. sapidus breeds throughout the year with two well differen­tiated periods, one of high reproductive intensity (March-October, with maximum between April and June), and another of lesser intensity (November-February).
7

The sexual maturation of mackerel icefish [Champsocephalus gunnari Lonnberg, 1905] from different regions of the Antarctic

84%
Sosinski J., Trella K.
Bulletin of the Sea Fisheries Institute
|
2002
|
nr 2
8

The quality of porcine oocytes is affected by sexual maturity of the donor gilt

67%
Pawlak P., Renska N., Pers-Kamczyc E., Warzych E., Lechniak D.
Reproductive Biology
|
2011
|
tom 11
|
nr 1
9
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Genetic and production trends in New Hampshire laying hens over 8 generations

67%
Calik J.
Acta Scientiarum Polonorum. Zootechnica
|
2011
|
tom 10
|
nr 3
The aim of the study was to determine trends for genetic and production parameters in a population of New Hampshire N-11 laying hens over 8 generations. Individual performance testing included body weight at 33 weeks of age (g), egg weight at 30 weeks of age (g), age at puberty expressed as days of age at first egg (days), and number of eggs laid to 39 weeks of age. As a result of implementing the genetic improvement programme based on NOVASEL electronic data processing system, egg production was increased, age at first egg was advanced and body weight of the chickens decreased in the N-11 line. The analysis of estimates of effective population size (Ne) and coefficients of inbreeding (Fx) shows that the cockerel and hen mating system used for reproduction effectively protects the population from an increase in inbreeding.
10

Farming and histological effects of gonadotropin stimulation in edible snails of the Helix genus

67%
Lysak A., Ligaszewski M., Mach-Paluszkiewicz Z., Juchno D.
Annals of Animal Science
|
2002
|
tom 02
|
nr 2
11

Effects of tamoxifen dose and nutrition scheme during growth on stimulation of the reproductive system in Cornish breed cocks

67%
Lisowski M., Bednarczyk M.
Folia Biologica
|
2005
|
tom 53
|
nr 1-2
12

Reproduction in Eurasian wild boar in central Punjab, Pakistan

67%
Ahmad E., Brooks J. E., Hussain I., Khan M. H.
Acta Theriologica
|
1995
|
tom 40
|
nr 2
Five hundred nineteen Eurasian wild boar Sus scrofa (Linneaus, 1758) were collected from March 1987 to July 1990 by shooting in crop and noncrop areas of central Punjab, Pakistan. The male-to-female ratio was 45.7 to 54.3. The age compo­sition consisted of 48% of the boar being < 12 months; 29%, 13 to 24 months; and 23% > 24 months. Males attained sexual maturity between the ages of 5 to 7 months and females between 4 and 6 months. The testes weights of males changed seasonally, as did the ovarian weights in females. Pregnancies were recorded primarily between February and May; a few were seen in August and September. Almost 32% of all sexually mature females were visibly pregnant during the study. Most animals were born during the months of April through September. Overall litter sizes averaged 5.7 ± 2.2 (SD). However, the number of young per litter in females < 12 months (4.9 + 2.0) was less than, but not statistically different from, the number in females > 12 months (5.9 ± 2.2). Annual production per female < 24 months averaged only 1.3 young, while females > 24 months averaged 3 young. The interaction of photoperiod, summer rainfall, and vegetation development probably determines the timing of the breeding seasons each year.
13

Temporal [1980-2001] and geographic variation in the sexual maturity at age and length of herring and sprat inhabiting the Southern Baltic

67%
Grygiel W., Wyszynski M.
Bulletin of the Sea Fisheries Institute
|
2003
|
nr 2
14

Biometric analysis of the American paddlefish Polyodon spatula [Walbaum, 1792]

67%
Kolman R., Szczepkowski M.
Acta Scientiarum Polonorum. Piscaria
|
2003
|
tom 02
|
nr 1
15

Attainment of sexual maturity by hybrids of rudd, Scardinius erythrophthalmus [L.] and carp bream, Abramis brama [L.] under experimental conditions

67%
Kopiejewska W., Terlecki J., Chybowski L.
Acta Ichthyologica et Piscatoria
|
2004
|
tom 34
|
nr 1
Background. In case of natural hybridisation of fish it is important to determine whether the hybrids attain sexual maturity and whether they can produce generation F2. The hybrids of rudd and carp bream, relatively frequent under natural conditions, have not been studied in the aspect of sexual maturity attainment. Materials and Methods. Histological examinations of gonads of 4-5 year old rudd and carp bream hybrids were carried out in experimental environments during the pre-spawning and spawning seasons of the parental species. Results. In development of oocytes the female hybrids of rudd and carp bream reached the stage of migrating nucleus and deterioration of the morphological structure of the nucleus. In case of male hybrids the presence of spermatids was confirmed. The stage of spermatozoa was not observed in case of hybrids of rudd and bream. In case of the control species (rudd) that stage was also not observed. It is possible that the lack of that stage was affected by the parameters of the culture environment. Nevertheless, the sexual products of male hybrids of rudd and bream as well as rudd were deposited. Conclusion. The studies show that the hybrids of rudd and carp bream may reach sexual maturity in the natural environments.
16

Precociously developed Ascarophis sp. [Nematoda, Spirurata] and Hemiurus levinseni [Digenea, Hemiuridae] in their crustacean intermediate hosts

51%
Jackson C. J., Marcogliese D. J., Burt M. D. B.
Acta Parasitologica
|
1997
|
tom 42
|
nr 1
Two adult and one subadult (L₅) Ascarophis sp. were recovered from amphipods Gammarus spp. sampled in Métis Bay, Quebec. Sexually mature metacercariae of Hemiurus levinseni were found in the mysids Neomysis americana and Mysis stenolepis collected from St. George’s and St. Ann’s Bay, Nova Scotia. Both of these helminths are normally parasites of fish as adults. Precocious development may result in either the acceleration of gamete production in an intermediate host or a shortened life cycle where the usual obligatory vertebrate host is no longer required.
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