Comparison of Cobb and Ross strains in embryo physiology and chick juvenile growth.

Broiler performance is known to be related to embryonic developmental parameters. However, strain or genotype differences with regard to embryo physiological parameters and juvenile growth have received little attention. A total of 1,200 hatching eggs produced by Cobb and Ross broiler breeders of the same age were studied. At setting for incubation and between 66 and 130 h of incubation, egg resonant frequency (RF) was measured as an indicator of embryonic development. Also, eggs were weighed before setting and at d 18. From d 10 to 18 of incubation, remaining albumen was weighed. During the last days of incubation, hatching events such as internal pipping (IP), external pipping, and hatch were monitored every 2 h. Hatched chicks were recorded and weighed. At IP stage, gas partial pressures in the egg air chamber were measured. Hatched chicks were reared for 7 d and weighed. Results indicate that RF of Ross eggs were lower than those of Cobb eggs (P < 0.01) and starting time point of RF decrease occurred earlier in Cobb eggs than in Ross eggs. Relative egg weight loss up to 18 d of incubation was lower in Cobb than in Ross (P < 0.05). At IP, partial pressure of CO(2) was higher in Cobb than in Ross (P < 0.05) with shorter incubation duration in Cobb. Between 6 and 60 h posthatch, heat production was higher in Cobb than in Ross (P < 0.05). At 7 d posthatch, Cobb chicks were heavier than Ross chicks (P < 0.05). It is concluded that Cobb and Ross embryos-chicks have different growth trajectories leading in different patterns of growth resulting from differences in physiological parameters

Comparison of Lohmann white and Lohmann brown strains in embryo physiology

peer reviewedChicken post-hatch performance is known to be related to embryonic developmental parameters. However, strain or genotype differences with regard to embryo physiological parameters have received little attention. A total of 1,200 hatching eggs produced by Lohmann Brown (LB) and Lohman White (LW) breeders of the same age were studied. Between 62 and 150 h of incubation, eggs Resonance Frequency (RF) was measured as indicator of early embryonic development. Also, albumen pH was measured between setting and d 8 of incubation. From d 10 to 18 of incubation, remaining albumen and embryos were weighed. During the last days of incubation, hatching occurrences were monitored after every four hours and hatched chicks were recorded. Results indicate that RF of LWeggs were lower than that of LB eggs (p<0.01) and starting time point of RF decrease occurred earlier in LB eggs than in LW eggs. Albumen pH of LB eggs was lower than that of LW eggs at day 8 of incubation. Remaining albumen weight at 14 and 16 d of incubation was lower in LB than in LW (p<0.05) while embryo weights increased more rapidly in LB strain than in LW strain. It is concluded that LB and LW embryos have different growth trajectories and should be incubated at different conditions. © Asian Network for Scientific Information, 2010

Unterschiedliche reaktion von masthühner- und legehennenembryonen auf verschiedene dosierungen von L-Carnitin. 1. Brut und Blutparameter

peer reviewedL-carnitine enhances the transport of long chain fatty acids through mitochondrial membrane. It can be produced by animals' organism from lysine and methionine. However, it was reported that chicken embryos have a limited capacity to synthesize L-carnitine. For this study, hatching eggs from Ross and Isa Brown breeders of 35 wk old (600 eggs per line) were used. At d 18 of incubation, eggs from each genotype were divided into 4 groups i.e. control eggs, Saline (injection of saline solution), eggs injected with L-carnitine of 500 μmol (LC500) or 1000 μmol (LC1000). At hatch and 7 d post hatch, blood samples were collected for triglyceride, glucose, total protein, uric acids, triiodothyronine (T3), thyroxine (T4) and corticosterone concentrations determination. Results indicate that hatchability and percentage of chick of optimal quality were higher in Ross than Isa Brown. Overall, layer chicks had higher levels of T4, total protein and uric acid than broiler chicks. With regard to L-carnitine injection, eggs of LC1000 groups had the lowest hatchability and this negative effect was more pronounced in Isa Brown eggs. At hatch and 7 d post-hatch, control chicks had the lowest levels of triglyceride and T3 but the highest levels of T4. At 7 d-old, the highest and the lowest levels of corticosterone were obtained in chicks of LC1000 and LC500 groups, respectively, compared to control and saline groups. In conclusion, L-carnitine administration during embryonic life affected differentially hatchability and blood parameters during post-hatch juvenile growth and this in a dose dependent manner. © Verlag Eugen Ulmer, Stuttgart

Interaction between ascites susceptibility and CO during the second half of incubation of two broiler lines. Effect on embryonic development and hatching process.

1. Because CO(2) during the second half of incubation is known to influence air cell and blood gases, and embryo development, it is postulated that post-hatch development and ascites sensitivity could also be influenced. 2. An ascites susceptible (A) and an ascites resistant (E) broiler line were incubated under standard incubation or high CO(2) conditions (up to 4%) from embryonic day (ED) 10 onwards. The embryonic development and the hatching process of these two lines were compared when incubated under standard or high CO(2) conditions from over the second half of incubation. 3. The A line, selected for high post-hatch growth rate, exhibited a higher relative embryo weight from ED10 until ED16, which was supported by a higher air cell pCO(2), lower air cell pO(2), higher corticosterone and thyroid hormones and earlier hatching time. 4. Incubation under high CO(2) increased air cell pCO(2), retarded yolk consumption, and decreased glycogen concentration in the liver at hatch. Hatchability decreased in both lines when incubated under high CO(2), due to an increased late mortality of embryos that died before IP. 5. These results suggest that the development and metabolism of CO(2)-incubated embryos differ from control incubated embryos

Effects of in ovo administration of L-carnitine on hatching events and juvenile performance of layer-type chick

peer reviewedThe effects of in ovo injection of L-carnitine on hatchability and juvenile performance of 360 layer-type chicks were investigated. Fertilized eggs were injected in air chamber with L-carnitine (500 and 1000 umol) dissolved in 0.9% of Saline (NaCI) at d 18 of incubation. Two control groups (non-injected and injected with 0.9% of Saline were also included. Hatched chicks was recorded after every 4 h, beginning at 490 h of incubation and ending at 514 h, for incubation length and hatching spread determination. At the end of incubation, hatched chicks were recorded according to treatment for determination of hatchability. At 3, 7 and 14 d post-hatch, chick body weight (BW) and morbidity were recorded. Also, at d 3 and 7 post-hatch, 14 birds from each of 2 replicate groups within each treatment were used for intestine and yolk sac weight determination. Results indicate that BW, hatchability, or relative intestine weights were not affected by treatment. However, incubation length was longer while hatching spread was shorter in L-carnitine groups compared to control groups. Yolk sac relative weight was decreased by treatment with L-carnitine (P < 0.05). Also, the percentage of chicks showing morbidity sign was lower in L-carnitine treated groups from d 7 onwards. The results of the present study suggest that in ovo injection of L-carnitine at d 18 of incubation delayed hatching time but resulted in narrower hatching spread, faster utilization of yolk sac content and improved morbidity. © Asian Network for Scientific Information, 2010