Effect of Ammonia at Different pH Levels on Larval Penaeus Monodon

Abstract

Black porgy,Acanthopagrus schlegeli,is one of the protandrous hermaphrodites.It is male during the two years,and begins to sexually reverseto female after 3 years old.The reproductive endocrine system and spermatogenesisincluded spermiation in the black porgy are not well understood.Therefore,the objectives of these studies were to investigate the responsesof the milt volume,sperm concentration and the profiles of steroid hormonesin black porgy stimulated with LHRH-A and HCG.Two-year-old black porgywere used in these studies.There was a very high correlation between theoptical density at 660nm and sperm number in milt.Based on the value ofthe optical density at 660nm,it was found that the milt volume was significantly increased,without decreasing sperm concentration,after two injectionsof LHRH-A and HCG.Plasma testosterone was also increased,however,estradiol-17βwas not changed significantly.The stimulation effects of LHRH-Awere much better than those of HCG.本研究之目的在探討雄性黑鯛經過LHRH-A或HCG刺激後，精液體積、精子濃度及血液中之性類固醇濃度之變化型態。精液在660 nm吸光值與血球計數盤所得之精子數目是互相成正比性之關係（r=0.92），因此可應用為估計黑鯛精子之濃度。而以LHRH-A及HCG注射後，可顯著的增加產精液體積，且其精子濃度無顯著之下降。激素注射後，血液睪固酮之濃度有顯著的上升，而雌二醇並無改變，且LHRH-A之反應效果比HCG顯著。