highly significantp < 0.001
Despite a trend for a global treatment effect, IGF levels were not significantly different between the three groups whatever the photoperiod ( p = 0.078). Highly significant differences in testis size (Fig. 7a ) and testosterone levels (Fig. 7b ) occurred between each photoperiod ( p < 0.001) but treatment did not affect these parameters ( p = 0.726 and p = 0.203, respectively).