Compensatory growth of broiler chickens is associated with an enhanced pulsatile growth hormone (GH) secretion: preferential amplification of GH secretory burst mass.

1. The present study was conducted to establish the effect of compensatory growth of broiler chickens on pulsatile growth hormone (GH) secretion. 2. Exposing male broiler chickens to intermittent lighting (IL) at 10 d of age was associated with a transient reduction in body weight gain which was followed by compensatory growth from 4 weeks of age onwards. At 34 d of age, cannulated IL broiler chickens manifesting compensatory growth and control chickens reared under continuous illumination (CL) were serially sampled at 10 min intervals over 5 consecutive hours and plasma GH concentrations measured. The resultant GH time series were analysed by deconvolution analysis. 3. The overall mean GH concentration was higher for IL than for CL broilers. The burst frequency did not differ between lighting treatments, but during each GH surge, IL broilers released a higher GH mass which resulted in higher GH amplitude values. As a consequence, GH production rates of IL broilers during the entire sampling session were markedly elevated compared to those of their age-matched CL broilers. There were no differences in the monoexponential GH half-life. 4. Compensatory growth in broiler chickens is associated with an amplification of GH secretory burst mass. The underlying causal mechanisms remain to be elucidated.