Temporal secretory patterns of growth hormone in young meat-type poultry

Temporal secretory patterns of plasma growth hormone were measured in young, male meat-type poultry at three stages (22, 30 and 44 d of age) during normal growth. Birds were cannulated in the jugular vein and, after a 2-d period of recovery were serially bled every 10 min for 3.5, 5.5 and 10 h for birds 22, 30 and 44 d of age respectively. GH secretion was found to be pulsatile and episodic, with a mean (+/- SE) peak frequency (number/h) of 0.85 (+/- 0.03) over all ages (n = 15). Birds at 22 d of age had significantly greater peak magnitudes, baseline concentrations and overall mean concentrations than those at 30 and 44 d of age.