Interaction between ascites susceptibility and CO2during the second half of incubation of two broiler lines: the effect on post-hatch development and ascites mortality

Interaction between eggshell temperature and carbon dioxide concentration after day 8 of incubation on broiler chicken embryo development

Carbon dioxide (CO₂) is considered to be an important factor during incubation of eggs. Effects attributed to higher CO₂ concentrations during experiment might be due to confounding effects of other environmental conditions, such as incubation temperature. To disentangle effects of eggshell temperature (EST) and CO₂ concentration, an experiment was conducted. A total of 630 Cobb 500 hatching eggs from 37 to 45 wk commercial breeder flocks were collected and incubated according to treatments. The experiment was setup as a complete randomized 2 × 3 factorial design, resulting in 6 treatments. From day 8 of incubation onward, broiler eggs were exposed to one of two EST (37.8 or 38.9 °C) and one of three CO₂ concentrations (0.1, 0.4 or 0.8%). Eggs were incubated in climate-respiration chambers and metabolic heat production was determined continuously. At day 18 of incubation and at 6 h after hatching, embryo and chicken quality were determined by evaluation of organ weights, navel condition, blood metabolites and hepatic glycogen. Hatching time and chicken length at 6 h after hatching showed an interaction between EST and CO₂ concentration (both P = 0.001). Furthermore, no effect of CO₂ concentration was found on embryo development or chicken quality. Metabolic heat production between day 8 and 18 of incubation was not affected by either EST or CO₂. At day 18 of incubation, an EST of 38.9 °C resulted in a higher egg weight loss, longer embryos, higher yolk free body mass (YFBM) and lower heart weight than an EST of 37.8 °C (all P < 0.008). At 6 h after hatching, an EST of 38.9 °C resulted in a higher residual yolk weight and lower YFBM, liver weight and heart weight than an EST of 37.8 °C (all P < 0.003). Lactate, uric acid and hepatic glycogen were not affected by EST at either day 18 of incubation or at hatch. Glucose was not affected by EST at day 18 of incubation, but at hatch, it was higher at an EST of 37.8 °C than at an EST of 38.9 °C (P = 0.02). It can be concluded that effects of CO₂ concentration (at concentrations ≤0.8%) on embryonic development and chicken quality appear to be limited when EST is maintained at a constant level. Moreover, a higher EST from day 8 of incubation onward appears to negatively affect chicken quality at hatch.

Evaluation of cardiac status, ascites related factors and growth performance of five commercial strains of broiler chickens

The aim of the current study was to evaluate cardiac status, ascites susceptibility, thyroid hormones, some hematological parameters and performance of five commercial broiler strains. Chicks were selected from strains of Cobb, Hubbard, Ross 308, Arbor Acres, and Arian (Iranian commercial broiler strain). Management and nutritional conditions were the same for all strains. Ascites related factors, and growth performance were measured. The highest and lowest, RV weight/live weight at 21 day of age were related to Arian and Ross 308 strains, respectively (p < 0.05). The TV weight, TV weight/live weight and the RV weight/live weight were significantly different between various strains at 49 and 54 days of age (p < 0.05). Strain had no effect on RV/TV. Performance, T3 and T4 hormones, hematological parameters, and mortalities were not significantly different among the strains (p > 0.05). Ascites mortalities in the Ross 308 was zero; however, it had no significant difference with other strains (p > 0.05). It was concluded that, based on performance and physiological status, even though considered broiler strains did not differ significantly because of the same genetic programs probably, but according to the prices and market conditions each can be selected for breeding.

Effect of carbon dioxide during the early stage of duck egg incubation on hatching characteristics and duckling performance

Gaseous exchange is very important for embryonic development during the incubation of bird eggs. The present study was carried out to investigate the effect of carbon dioxide (CO₂) pumping during the first 10 days of Pekin duck egg incubation on hatching characteristics, embryonic growth, hormonal concentrations and the post-hatch weight of the ducks. Two different ventilation conditions were used in this study. In one condition (V), the incubator was ventilated standard. In the other condition (NV), CO₂ was gradually pumped into a non-ventilated incubator to reach and maintain a 1% concentration through the first 10 days of incubation, after which the incubator was ventilated for the rest of the incubation period. The CO₂ percentage in the V incubator was constant at approximately 0.18%; by contrast, in the NV incubator, the concentration was increased gradually from 0.17% to 1%, where it was maintained through the 10th day of incubation. Throughout the incubation period, the egg weight loss and the embryonic mortality percentages were significantly lower in NV than in V. The hatchability of fertile eggs and the weights of ducklings at hatch were significantly higher in NV than in V. The embryonic T₃, T₄ and corticosterone levels in NV were significantly higher than those in V. Additionally, the haematological parameters (haemoglobin, packed cell volume and red blood cells) of the embryos were significantly higher in NV than in V. Furthermore, a total of 1198 ducklings for the V and NV conditions, all one day old, were individually weighed and then transferred into randomly assigned floor pens with 3 replicates for each ventilation condition. The feed conversion ratio of the ducks was significantly lower in NV than in V, while the reverse was true of body weight at different ages. Therefore, we can conclude that the NV condition with circulation of CO₂ for the first 10 days of incubation is preferable to the V condition.

INFLUÊNCIA DOS NÍVEIS DE CO2 E DO TIPO DE INCUBADORA SOBRE O DESEMPENHO ZOOTÉCNICO E MORFOMETRIA CARDÍACA DE FRANGOS DE CORTE

Resumo O objetivo do trabalho foi avaliar incubadoras de estágio múltiplo e único e diferentes níveis de CO2 sobre o desempenho, número e diâmetro das fibras musculares, morfometria cardíaca e rendimento de carcaça de frangos de corte. Foram incubados 2.520 ovos férteis em um delineamento inteiramente ao acaso, distribuídos em quatro níveis de CO2 (4.000, 6.000, 8.000 e 10.000ppm) em incubadoras de estágio único durante os primeiros dez dias de incubação e um tratamento controle utilizando uma incubadora de estágio múltiplo, totalizando cinco tratamentos com 504 ovos em cada um. Após a eclosão, 1.050 pintos machos foram alojados de acordo com o delineamento utilizado no incubatório. A hipercapnia aplicada nos primeiros 10 dias de incubação afetou o ganho de peso e a conversão alimentar dos pintos na primeira semana de vida, no entanto, esses efeitos não foram mantidos até o final do período de criação. Não houve efeito de incubadoras ou da hipercapnia sobre a morfometria muscular e cardíaca. Houve maior rendimento de coxas das aves na idade de abate oriundas de incubadoras em estágio único com até 6.000 ppm de CO2, quando comparadas à incubação em máquinas de estágio múltiplo. Esse efeito pode ser atribuído à maior vascularização induzida pela hipercapnia precoce.