Effects of treadmill exercise on the transfer of plasma triglyceride into the ovary of the laying fowl

Abstract

1. The effects of 90 min continuous treadmill exercise on the plasma‐to‐ovary transfer of ^l4C‐labelled triglycerides in laying hens were examined.

2. Exercised birds showed a 4‐fold increase in plasma free fatty acid concentration, a 15% decrease in plasma glucose concentration and unchanged plasma triglyceride concentration compared with resting controls. The mean plasma‐to‐ovary triglyceride transfer rate was approximately halved by exercise.

3. The surface area‐specific triglyceride transfer rate was greatest for oocytes weighing 0.25–1.5 g and decreased with increasing oocyte size. The lowest rates were in the small (<0.25 g) white oocytes. This pattern was largely unaffected by exercise.

4. Factors that might be responsible for the reduction in triglyceride transfer into the oocytes during exercise include hormonal effects on the permeability of the oocyte envelope, increased competition for plasma lipids by the working muscles and reduced blood flow to the ovary, as a result of the release of vasoconstrictors.