ABSTRACT:The aim of the study was to analyze the pattern of oviposition time in laying sequences in broiler breeder hens and to determine a relationship between egg position in the sequence and egg quality. The sequences were described using mean oviposition time (hour) within a sequence, mean lag of oviposition time between successive ovipositions, and mean and cumulative lag of oviposition for a sequence. Egg weight, percentage of egg components and shape index were determined for successive eggs in a sequence. The 2-, 3-, 4-, 5-to 6-and 7-to 9-egg sequences were considered. The light/dark regime was 16 h/8 h (05:00 a.m. to 09:00 p.m.). Hens laid the first egg in a sequence about 3.5 h after the beginning of the photoperiod. With increasing sequence length, the first egg was laid sooner after the beginning of the photoperiod and the intervals between successive ovipositions shortened. This suggests that when planning the frequency of egg collection in a flock of broiler breeder hens, one should account for changes in the egg sequence length during the production period. No significant relationship between egg position in the sequence and quality of egg components was observed.
BackgroundThe lack of a sufficient number of molecular markers seriously limits the cognition of genetic relationships within and between populations of many species. Likewise, the genetic diversity of domestic goose (Anser anser domesticus), with a great number of breeds throughout the world, remains poorly understood at the molecular level.FindingsThirty-five goose, seventeen duck and eight chicken microsatellite primer pairs were screened for their utility in the cross-species amplification on DNA from 96 individuals of Zatorska breed of domestic geese. Twenty-seven of 42 amplifying primer pairs revealed length-polymorphic products, but three of them were difficult to score. Fifteen primer pairs amplifying the same length product across all individuals. One polymorphic microsatellite locus was assigned by genotyping of known sex individuals to the Z-chromosome.ConclusionsWe present a set of 24 polymorphic microsatellite markers useful for population genetic studies of the domestic goose. Another 15 markers were classified as monomorphic, but they might also be suitable for the assessment of genetic diversity in geese.
ABSTRACT:The structure of the Zatorska breed was estimated in the context of the realized conservation program. The level of genetic diversity and effective population size were estimated as well. The following parameters were evaluated: pedigree completeness index, genetic diversity, inbreeding level, individual increase in inbreeding, generation interval, and parameters connected with general condition of the population. The whole population of the Zatorska breed was housed in an experimental farm of the University of Agriculture in Cracow (Poland). Records were extracted from the studbook. Totally 5514 individuals hatched between 1990-2013 (2835 males and 2679 females) were included in the analysis. The average number of discrete generation equivalents reached 3.76, whereas the maximum discrete generation equivalent was 9.98. The average inbreeding level was low amounting to 1.46% for the whole population and 3.02% for the inbred individuals. The average pedigree completeness index for five generations reached 59.12%, for 10 generations 37.39%, and for all 16 generations it was 23.53%. The average effective population size was estimated from the family size variance and amounted to 67.36 individuals. It can be concluded that the conservation breeding program in the Zatorska goose has been going on well. This is confirmed by the magnitude of obtained estimates of parameters such as a low inbreeding level across generations under satisfactory pedigree completeness. On the other hand, the structure of a small population may be liable to fluctuations. Hence, continuous monitoring of the endangered population (including molecular control) seems to be necessary.
The study was performed to determine the hormonal status of mature germline chimeras obtained by blastodermal cell transfer from chicken embryos of a donor breed [Green-legged Partridgelike breed (GP) x Araucana (AR)] to those of a recipient breed [White Leghorn (WL)] being at the same stage of embryonic development. The egg-laying chimeras and WL hens (control) of the same age were used in the experiment. At first, blood samples were taken from each bird at 0.5, 5, 12.5 and 18.5 h following oviposition. Subsequently, the chimeras and the WL hens were decapitated 1-2 h after ovulation. A stroma and the following follicles were isolated from the ovary: white normal (1-4, 4-6 and 6-8 mm), white atretic and yellow preovulatory follicles (F4-F1). Sex hormones, progesterone (P4), testosterone (T) and oestradiol (E2) in blood plasma and ovarian follicles were determined radioimmunologically. The activity of the 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the granulosa and theca layers of the follicles was analysed histochemically. In chimeric chickens, a higher level of T in blood plasma during the ovulatory cycle was noticed. However, in the stroma, white prehierarchical and medium-size preovulatory ovarian follicles the level of T was significantly lower. With respect to E2, its elevated levels were found both in blood and in the ovarian follicles. There were no significant differences in P4 concentrations in blood plasma while in ovarian follicles a higher level was observed only in white 6-8 mm follicles. 3beta-HSD activity in granulosa and theca layers of the ovarian follicles in chimeras was not different from that in the WL hens. In conclusion, the results obtained indicate that germline chimeras exhibit significant alterations in sex hormone levels in the ovary and blood plasma, which in turn may affect their reproductive abilities.
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