Quality parameters in eggs of layer cross Hisex brown as affected by the oviposition time

Chicken eggs are valuable and chip source of the nutrients in human diets; this fact has propelled the interest toward the availability of this commodity and modification of its chemical composition in desirable directions. The morphology of the eggs is closely correlated with certain parameters of nutritive value and shelf life. The formation of eggs is a long process: the maturation of large yellow follicles in the ovarian hierarchy (until the ovulation) lasts for 7-10 days; the formation of egg in the oviduct (since ovulation to oviposition) takes 22.5-26.1 hours, depending on age and productivity level in parental hen. The quality of eggs is affected by multiple factors acting before the oviposition (breed and cross of chicken, individual physiological peculiarities, live bodyweight, laying rate, oviposition time, age, the regimes of management and nutrition, artificially induced moult, stresses, health status) and after the oviposition (conditions of collection, transportation, storage, washing and sanitary treatments, the effects of these factors being also depend on the initial egg quality formed before the oviposition. The optimization of egg quality requires the thorough knowledge on mechanisms and factors involved. In the study presented it was found out that oviposition can affect different parameters of egg quality though insignificantly with the exception of B2 content. The effects of the oviposition time on egg quality was studied on five treatments of commercial Hisex Brown layers (Hendrix Genetics BV, the Netherlands) since 210 to 450 days of age housed in cage batteries mounted in standard windowless poultry house (7 birds per cage) with constant lighting regime 14L: 10D with the onset of lighting at 5 am, setout at 7 pm. The eggs were collected during 5 periods of a day: 5-8 am (treatments 1), 8-10 am (treatment 2), 10-12 am (treatment 3). 0-2 pm Treatment 4), and 2-4 pm. Average weight of the “earliest” eggs (laid until 8 am) was significantly higher (by 2.1-2.5 g or 3.6-4.4 %, p 2 in yolk at early hours (5-8 am) as compared to later hours (p 75 g); other external parameters of egg quality were generally similar in all treatments; however, egg weight tended to increase with hen age. The relative weight of the albumen was similar at 420 and 450 days of age, with the minimal index shape eggs laid in the interval 0-2 pm being found (with the exception of 210 and 450 days of age; p function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }