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The study aimed at determining the hatchability of turkey eggs as related to the shell surfach characteristics (regular shells, rough shells and pigment-spotted shells – group 1, 2 and 3, respectively). A total of 17 590 eggs of Broad-breasted White Turkeys, marked individually, were considered during the peak of the laying season. Shell microstructure was examined of 60 eggs from each group, using a scanning electron microscope while hatchability was estimated based on fertilization rate, percentage of dead embryos and hatching rate (healthy poults only).The main differences between the shells from group 1 and 2 included different size of cuticular plates, thicker crystal layer, thinner palisade and mammillary layers, curved walls of the mammillae, and thicker fibres of the inner shell membrane. Eggshells from group 3 showed a significantly thicker crystal layer and curving fibres of the inner shell membrane compared to group 1 shells.The hatching rate of set eggs was highest (77.15%) in group 1. Embryo mortality rates were by 4.9 and 5.4 per cent points higher in eggs from groups 2 and 3, respectively, than in eggs from group 1.The hatchabilities of rough-shelled eggs (group 2) and eggs with pigment spots (group 3) appeared lower than of eggs with regular shells (group 1).
The purpose of the study was to investigate the effect of service sire on fertilization rate and loses during hatching as a way of increasing the accuracy of breeding value estimation of layers for hatchability. Layers from five generations of two breeds – Rhode Island White and Rhode Island Red – were individually recorded for fertilization rate, percentage of chicks hatched from eggs laid,set, and fertilized. Two statistical models, both fitting random animal additive genetic and permanent environment effects along with fixed joint effect of hatch-year × hatch-number, differed with regard to presence or absence of random effect of service sire. Of the traits studied fertilization rate is least influenced by service sire which can be neglected when evaluating fertilization. Although sernice sire effect is small, both absolutely and relatively, failing to account for it in a model evaluating number of chicks hatched may result in substantial overestimation of heritability. Service sire effect accounted for in the model can also add to the accuracy of the hens’ proofs for hatchability.Correlation between direct additive and service sire effects may be dependent on the population it is estimated in.
Chitosan is the simplest form of chitin, found in carapaces of crabs, prawns, and krill. Due to its chemical and physical properties and biological activity, chitosan is widely applied in, i.a., medicine, animal care, and agriculture. Chitosan effects on poultry health and production have been studied to a limited degree only. The present study was thus aimed at elucidating chitosan effects on the utility and reproduction-related characteristics of quail. The experiment involved the quail aged 5 weeks which were divided into two groups, each consisting of 36 females and 12 males. The birds belonging to Group I (control) were fed a standard feed mix for laying quail, while the feed offered to Group II (experimental) was enriched with 5.2 ml chitosan added to 1.2 kg feed. Compared to the control, the experimental quail showed a lower daily feed consumption, lower number of eggs laid, and a higher feed consumption per egg.
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