Changes in Japanese quail (Coturnix coturnix japonica) blood gases and electrolytes in response to multigenerational heat stress

Abstract

The average surface temperature is predicted to rise 0.5 to 6˚C by the year 2100. When Japanese quail (Coturnix coturnix japonica), a source of protein for many, are subjected to heat stress, their blood acid-base equilibrium and ability to regulate electrolytes may change. This disequilibrium may influence egg-shell quality, enzyme functions, and synthesis of tissue proteins. To determine effects of multi-generation heat stress on Japanese quail, the following treatments were applied (1) control (TN, non-sibling random mating at thermoneutral temperature [22.2˚C]); (2) thermoneutral siblings (22.2˚C, TNS); (3) heat stress (HS, non-sibling random mating at 31.1˚C); and (4) heat stressed siblings (HSS, siblings of TNS with high feed conversion ratios (FCR), 31.1˚C). Body weights (BW), blood gases, and electrolytes of quail were measured during the first 4 hours (acute) and after 3 weeks (chronic) of heat exposure (31.1˚C) in generation 10. ANOVA was used to determine statistical significance at P≤0.05. Models included treatments, length of exposure, sex, and their interactions. Results showed that acute and chronic heat stress did not have a clear effect on blood electrolytes, acid-base regulation, and oxygen transport. However, acute HSS males or females were significantly different than chronic TN males in BW, PCO2, PO2, sO2, and Na+. Chronic HS males and females did not have significantly different blood electrolytes, acid-base regulation, and oxygen transport than chronic HSS males and females. Thus, selection for low FCR in heat stress at 31.1˚C did not incur a fitness advantage when considering these parameters. Sexually mature males had significantly higher levels of hematocrit and hemoglobin compared to sexually immature quail and sexually mature females. Future studies using higher temperatures (32 to 34˚C) could inform producers when to expect significant physiological changes in quail, lending to adaptions of feeding regiments according to environmental temperature and age.