Heat stress effects on Japanese quail production and iSTAT

Heat-stressed Japanese quail (Coturnix coturnix japonica) can experience
blood acid-base disequilibrium and electrolyte disregulation. 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 of the above-mentioned treatments. Statistical
significance was determined at P ≤ 0.05. Models included treatments,
length of exposure, sex, and their interactions. Results showed that acute
and chronic heat stress at 31.1°C did not have a clear effect on blood
electrolytes, acid-base regulation, and oxygen transport. Across
treatments, sexes, lengths of exposure, and their interactions, 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 than sexually immature quail
and sexually mature females. Future studies using higher temperatures
(32–34°C) could inform producers when to expect significant physiological
changes in quail, lending to adaptions of feeding regiments according to
environmental temperature and age.