Acclimation to Heat During Incubation. 2. Embryo Composition and Residual Egg Yolk Sac Fatty Acid Profiles in Chicks

Abstract

The aim of the research was to evaluate embryo composition and changes in egg yolk fatty acid composition during embryonic development as a function of incubation temperature and age of breeders. Eggs obtained from a common breeder stock at 3 ages: 32 (younger), 42 (mid age), and 65 (older) wk were divided into 2 groups and placed into 2 incubators: the control and the second where eggs were heat-acclimated (HA) at 38.5 degrees C for 6 h daily from d 10 to 18 of incubation. Body composition of embryos and chicks were measured on d 14, 18, and at hatch, respectively. Fatty acid profiles of yolk and residual egg yolk sac of chicks were analyzed before incubation and at hatch, respectively. Moisture content of embryos was highest on d 14 and then decreased regardless of parental age and incubation temperature. Moisture content of chicks at hatch from 42- and 65-wk parents were lower than those of chicks from 32-wk parents, whereas the trend in chick fat content was opposite. Incubation temperature had no effect on composition of chicks. Consistently lower cis-4,7,10,13,16,19-eicosapentaenoic (docosahexaenoic acid, DHA; 22:6n-3) and cis-11,14,17-eicosatrienoic (20:3n-3) fatty acids in the residual yolk sac of chicks than in egg yolks before incubation may have resulted from preferential uptake from the yolk. The DHA content in the residual yolk sac was considerably higher in chicks from older parents incubated at HA, whereas, in contrast, levels of 18:3n-3 were lower. Also, chicks from younger parents in the HA treatment had lower transported 18:3n-3 and higher levels of transported DHA. It may be concluded that this process observed during the high incubation temperature may be related to a protective strategy and thus contributes to postnatal heat adaptation.

Determination of the effects of aflatoxin B1givenin ovoon the proximal tibial growth plate of broiler chickens: histological, histometric and immunohistochemical findings

“…The weight and percentage of drymatter accumulation of embryos are closely related to the fatty acid composition of the yolk (Peebles et al, 1999). Thus, the yolk and its fatty acid content are essential for meeting the nutritional requirements of developing embryos (Yalcin et al, 2008). In this study, the yolk sac weight was significantly higher in AFB 1 -treated groups than those of the control birds.…”

Thermal stimulation of Ross®-lineage embryos on a commercial scale

“…WINELAND et al (2006ab) and LEKSRISOMPONG et al (2007) reported that lower average weights of chicks and their organs after heat stimulation. Other researchers (YALÇIN et al, 2008) increased the incubation temperature to 38.5ºC for six hours per day from the 10 th to the 18 th day, and reported accelerated growth compared to the control group with greater chick weight. This effect was not observed by YALÇIN & SIEGEL (2003), who assessed the effects of higher temperature (39.00ºC).…”

Egg storage and breeder age impact on egg quality and embryo development

“…The absorption and utilization of nutrients from the yolk sac by the embryo are affected by breeder age (Burnham et al, 2001;Nangsuay et al, 2011;Peebles et al, 2000;Yadgary, Cahaner, Kedar, & Uni, 2010;Yalcin et al, 2008). Nangsuay et al (2011) reported at hatch a higher absolute yolk sac absorption (16.6 vs. 12.6 g), yolk sac absorption percentage (84.4% vs. 78.8%) and a higher nutrient assimilation of dry yolk (+0.16 g/g of dry YFBM) in hatchlings of older flocks (53 weeks) compared to young flocks (29 weeks).…”