Effects of low oxygen during chorioallantoic membrane development on post-hatch growing performance of broiler chickens

Abstract

The prenatal circulatory system is adaptive and capable of plasticity designed for the needs of the growing tissue. When a broiler embryo is faced with hypoxic stress, the process of angiogenesis in tissues begins. Exposure to hypoxic conditions of 17% oxygen during the chorioallantoic membrane (CAM) development (E5 to E12) affected the circulatory system and contributed to an increase in the blood oxygen carrying capacity. The present study aimed to evaluate the effects of hypoxic exposure during CAM development on post-hatch performance of broilers and to examine whether hypoxic exposure improved sustainability of birds exposed to acute heat stress.Two consecutive trials, with male broilers from each of the incubation treatments-optimal conditions and exposure to hypoxia of 15 or 17% oxygen, for 12 h/day, during CAM development-were conducted. In experiment 1, 60 male chicks from each group were raised in individual cages. In experiment 2, 160 male chicks from each group were raised in 40-chick pens until marketing. On d 35, 20 birds from each group were transferred to individual cages kept at a temperature of 23°C for 72 h, and then birds were exposed to 35°C for 5 hours. Body temperatures were measured at 0, 2, and 5 h of the heat exposure. In both experiments BW, feed intake, and FCR were recorded. At marketing, chicks were slaughtered, and relative weights of breast muscle, abdominal fat pad, heart, and liver were calculated.Hypoxia treatment resulted in a FCR advantage. Food intake was similar in all treatments, but groups exposed to hypoxia grew better than controls until the age of 35 days. Hypoxia-treated groups had higher relative breast, heart, and liver weights than controls. Body temperatures of hypoxia-treated chickens remained lower during heat stress exposure, and their mortality rate was lower as well. Intermittent exposure to moderate hypoxia during CAM development confers advantages to broilers in feed utilization efficiency and in coping with heat stress. It may be considered as a mitigating step in incubation to facilitate broilers in achieving their full growth potential.

Effects of incubation temperature pattern on broiler performance

“…For instance, the higher blood glucose level at hatch indicates that more energy was available during the start of life and the higher relative stomach weight could indicate an improved development of the digestive tract. Furthermore, concerning the higher relative heart weight, it can be suggested that during grow-out with a high growth rate, a larger heart might improve provision of oxygen and nutrients to the tissues, and consequently, broiler grow-out performance might be improved ( Molenaar et al., 2011a ; Sozcu and Ipek, 2015 ; Druyan et al., 2018 ). However, grow-out performance at later ages showed opposite results.…”

Chicken Incubation Conditions: Role in Embryo Development, Physiology and Adaptation to the Post-Hatch Environment

“…Also, the findings of Huang et al (2017) showed that chronic hypoxia condition adversely affected survivability, feed conversion ratio and growth in broiler chickens. On the contrary, the findings of Druyan et al (2018) showed that hypoxic conditions did not alter the juvenile growth performance of broiler chickens using a hypoxic condition of 15 or 17% O 2 during a short period of embryonic development. The authors reported that hypoxic conditions improved the body weights of the birds at the market age.…”

“… Effect of hypoxia (17 or 15% O 2 ) on feed conversion ratio [adapted from Druyan et al (2018) ]. FCR, feed conversion ratio.…”

The Role of Incubation Conditions on the Regulation of Muscle Development and Meat Quality in Poultry

“…Increasing oxygen concentration to 27.5% during mid and late incubation phase improved this situation and increased broiler hatching weight ( Zhang et al, 2008 ). In contrast, exposing embryos to a low oxygen (17%) environment at E5–E12 increased 7D broiler body weight, a positive effect that lasted until 28D, and increased breast muscle production ( Druyan et al, 2018 ). This occurred probably because the low-oxygen environment stimulated the embryonic vasculature to develop in a good direction and to better deliver nutrients to the pectoral muscle, ( Hadad et al, 2014 ), thus promoting posthatch muscle development.…”

“…It was demonstrated that lighting and thermal adjustment during the incubation phases improves the number and activity of satellite cells, promotes muscle fiber development, increases the embryonic muscle fiber area ( Zhang et al, 2014 ) and improved meat quality ( Piestun et al, 2013 ). Incubation of chicken embryos in a hypoxic environment with 17% oxygen content improves posthatch broiler body weight and increases pectoral muscle production ( Druyan et al, 2018 ). Green light exposure during broiler incubation increased the number and proliferative activity of myogenic and satellite cells, promoted embryonic muscle fiber development ( Bai et al, 2019 ), and increased pectoral muscle production ( Zhang et al, 2012 ).…”