Differences in egg nutrient availability, development, and nutrient metabolism of broiler and layer embryos

Abstract

Selection for production traits of broilers and layers leads to physiological differences, which may already be present during incubation. This study aimed to investigate the influence of strain (broiler vs layer) on egg nutrient availability, embryonic development and nutrient metabolism. A total of 480 eggs with an egg weight range of 62.0 to 64.0 g from Lohmann Brown Lite and Ross 308 breeder flocks of 41 or 42 weeks of age were selected in two batches of 120 eggs per batch per strain. For each batch, 30 eggs per strain were used to determine egg composition, including nutrient and energy content, and 90 eggs per strain were separately incubated in one of two climate respiration chambers at an eggshell temperature of 37.8°C. The results showed that broiler eggs had a higher ratio of yolk: albumen with 2.41 g more yolk and 1.48 g less albumen than layers. The yolk energy content of broiler eggs was 46.32 kJ higher than that of layer eggs, whereas total energy content of broiler eggs was 47.85 kJ higher compared to layer eggs. Yolk-free body mass at incubation day 16 and chick weight and length at hatch were higher in broilers compared to layers. Respiration quotient of broiler embryos was higher than layer embryos during incubation day 8 to incubation day 10. A 0.24 g lower residual yolk at the hatch of broiler embryos than for the layer embryos indicated that broiler embryos used more yolk and had a higher energy utilization and energy deposition in yolk-free body mass. Heat production of broiler embryos was higher than that of layer embryos from incubation day 12 to incubation day 18, but efficiency of converting egg energy used by embryos to form yolk-free body mass was similar. In conclusion, broiler and layer embryos have different embryonic development patterns, which affect energy utilization and embryonic heat production. However, the embryos are equal in efficiency of converting the energy used to yolk-free body mass.

First week nutrition for broiler chickens : effects on growth, metabolic status, organ development, and carcass composition

“…This is somewhat higher than the RER value of 0.71 to 0.72 determined for incubated eggs at embryonic day 18 (Nangsuay et al, 2015), an incubation stage during which the chick primarily relies on lipids in the yolk as an energy source. However, during the final stage of incubation, the RER slightly increases due to glycogenolysis, which will deplete glycogen reserves at the actual moment of hatch Van de Ven et al, 2013).…”

“…Chickens were placed in one of 4 open-circuit CRC that provided 1,000 × 800 mm or 800 × 500 mm (length by width) animal floor space (Verstegen et al, 1987). A CO 2 recovery test was performed immediately prior to the start of the experiment, according to procedures described by Heetkamp et al (2015). In the 4 CRC, 99.3, 98.9, 99.8, and 99.7% of the CO 2 released was recovered.…”

“…In the 4 CRC, 99.3, 98.9, 99.8, and 99.7% of the CO 2 released was recovered. In the 2 smaller CRC, an additional ethanol oxidation test was performed to test air tightness of the CRC, according to Heetkamp et al (2015), yielding a respiratory quotient (RQ) of 0.66 in both chambers. The latter is in line with the theoretical RQ of 0.667 when ethanol is completely burned, thus proving that there are no air leakages in the CRC.…”

Effects of food and water deprivation in newly hatched chickens : a systematic literature review and meta-analysis

“…development (e.g. [123][124][125][126]). Whether these differences in embryonic development are associated with differences in chicken quality has not been established yet.…”

“…Type: layers and broilers are selected for different production purposes, which has led to physiological differences during incubation and post-hatching. For example, differences exist in egg composition[123], resulting in differences in chicken weight, residual yolk weight, and organ…”