Role of Body Weight on Reproductive and Physiological Traits in Japanese Quail Layers (Coturnix japonica)

The Japanese quail is a popular laboratory animal for scientific research. Its continued characterization is essential for attaining accurate and reliable results. This includes refining genetic and environmental variables that could affect its use in developmental biology, reproduction, physiology, nutrition, endocrinology and toxicology. The role of body weight as a means of assessing reproductive and physiological traits is presented here. Two groups of random bred Japanese quail layers of 240-days of age having a well-established production and fertility records but differing in body weights were used in the project. One group of birds (n = 10) weighed 120-130 grams (lighter birds) and the second group (n = 10) weighed 150-160 grams (heavier birds). The heavier birds had significantly higher weights of ovaries and oviducts as well as larger yellow-yolk containing ovarian follicles (p<0.05). The eggs laid by the heavier birds were also larger (p>0.05). Conversely, there was an increase in packed cell volume, plasma proteins and decrease in blood sugar levels (p<0.05) in the heavier birds as compared to the lighter birds. The body weight was found to have a distinct bearing on the weight of reproductive and physiological traits. One should be mindful of body weight when selecting Japanese quail for research projects.