Reproductive and metabolic endocrinology in the emu (Dromaius novaehollandiae). 1. Blood sampling stress, corticosterone response, and pulsatility in LH and prolactin secretion

Before investigating reproductive and metabolic endocrinology in the emu, we needed to test whether stress associated with blood sampling would disrupt the secretion of key hormones, and whether LH and prolactin secretion is pulsatile, thus dictating the sampling regime. In both sexes, we measured the delays from pen entry until sampling was completed by jugular venepuncture, and tested whether they were related to changes in serum corticosterone concentration, a stress indicator in birds. Generally, manual capture and restraint required less than 1 min, and jugular sampling required less than 30 s. Sustained increases in corticosterone concentration were seen only in the few birds that showed overt signs of restraint stress. We also assessed automated blood sampling equipment (ABSE) attached to a jugular cannula. Prolactin concentration was not affected by sampling method or by stress events. In frequent serial samples, the concentrations of LH, prolactin and sex steroids were sometimes irregular and episodic, but there was little evidence of pulses. In conclusion, in emus, pulsatile secretion is not an essential feature of the endocrine control of reproduction, and efficient manual sampling is not likely to interfere with studies of reproductive and metabolic processes. The ABSE needs refinement for the emu.