Effects of Incubator Carbon Dioxide and Oxygen Levels, and Egg Weight on Broilers' Hatchability of Fertile Eggs
BRAZILIAN JOURNAL OF POULTRY SCIENCE
Authors: Okur, N.
Abstract
This study investigated the effects of incubator carbon dioxide (CO2) and oxygen (O-2) levels, and egg weight (EW) on embryo mortality (EM) and hatchability of fertile eggs (HFE). A total of 1920 hatching eggs were obtained from a middle-aged (41 weeks) ROSS 308 broiler breeder flock. The eggs were classified according to EW as heavy (69.63 +/- 0.09 g), medium (65.20 +/- 0.04 g) and light (61.11 +/- 0.08 g) and randomly allocated to four separate identical incubators. To these incubators, four different incubator ventilation programmes (IVP) classified as control (C; 0.7% CO2 and 20.9% O-2), high CO2 (HC; 1.1% CO2 and 20.3% O-2), high O-2 (HO; 0.6% CO2 and 22.0% O-2), and high CO2 + O-2 (HCO; 0.9% CO2 21.0% O-2) were applied, and EM and HFE were examined. IVP affected EM and HFE; a higher rate of early EM and a lower rate of HFE were obtained from the HO group compared to the HCO group, and a lower rate of HFE was observed in the HO group than to the C group (p<0.05). An association was found between EW and IVP (p<0.05), being more evident in early EM for light eggs. Consequently, IVP; i.e., different CO2 and O-2 levels in the incubator affected the hatching results. This is considered to be due to the altitude of the experiment (724m) and the uniform eggs being obtained from the same middle-aged flock, and incubator O-2 levels should be taken into consideration, as well as CO2.
The unconventional role of HLA-E: The road less traveled
MOLECULAR IMMUNOLOGY
Authors: Grant, Emma J.; Nguyen, Andrea T.; Lobos, Christian A.; Szeto, Christopher; Chatzileontiadou, Demetra S. M.; Gras, Stephanie
Abstract
Histocompatibility Leukocyte Antigens, or HLAs, are one of the most polymorphic molecules in humans. This high degree of polymorphism endows HLA molecules with the ability to present a vast array of peptides, an essential trait for responding to ever-evolving pathogens. Unlike classical HLA molecules (HLA-Ia), some nonclassical HLA-Ib molecules, including HLA-E, are almost monomorphic. Several studies show HLA-E can present self-peptides originating from the leader sequence of other HLA molecules, which signals to our immune system that the cell is healthy. Therefore, it was traditionally thought that the chief role of HLA-E in the body was in immune surveillance. However, there is emerging evidence that HLA-E is also able to present pathogen-derived peptides to the adaptive immune system, namely T cells, in a manner that is similar to classical HLA-Ia molecules. Here we describe the early findings of this less conventional role of HLA-E in the adaptive immune system and its importance for immunity.