Effects of husbandry practices on spermatogenesis and sperm quality in Atlantic salmon broodstock

The project investigates effects of husbandry practices such as photoperiod and temperature manipulation on the process of spermatogenesis and on sperm quality in Atlantic salmon. The aim is to-fold: 1. To establish fundamental knowledge on the environmental and endocrine regulation of spermatogenesis 2. To evaluate effects of temperature and photoperiod on the effectiveness of spermatogenesis and potential harmful effects on sperm quality. Spermatogenesis will be assessed by a range of molecular, physiological and morphological methods. Particular attention will e given to effects of photoperiod and temperature on pituitary gene expression of GnRH-R(s), FHS-ß and LH-ß, gene expression of FS H-R, LH-R and AR's in thesis, and plasma levels of FSH, LH, testosterone, 11-ketotestosterone and 17,20ß during spermatogenesis.The steroidogenic capacity of the testis will by assessed in vitro. The effectiveness of spermatogenesis will be monitored by t echniques to study cell proliferation and apoptosis, as well as total sperm production (sperm volume, sperm count and spermatocrit), and correlated with the endocrine parameters to elucidate potential mechanisms. Sperm quality will be assessed by CASA (Co mputer Assisted Sperm Analysis) and correlated with the ability to fertilize eggs and provide egg survival to the eyed stage.