Fatty acids in female’s gonads of the Red Sea fish Rhabdosargus sarba during the spawning season

Objective:To determine the fatty acids profiles in female fish,Rhabdosargus sarba(R.sarba)from the Red Sea during the spawning season.Methods:Monthly individual R.sarba were obtained from Bangalah market in Jeddah,Red Sea and transported to the laboratory in ice aquarium.The total length,standard length and weight were measured,fishes were dissected.Ovaries were removed,weighed and 10 mL of concentrated hydrochloric acid were added to 10 g of the ovary in a conical flask and immersed in boiling water until the sample was dissolved and the fat was seen to collect on the surface.The conical was cooled and the fat was extracted by shaking with 30 mL of diethyl ether.The extract was bowled after allowing the layers to separate into a weighed flask.The extraction was repeated three times more and distilled off the solvent then the fat dried at 100℃,cooled and weighed.Then 50 mg of lipid was put in a tube,5 mL of methanolic sulphuric acid was added and 2 mL of benzene,the tube well closed and placed in water bath at 90℃for an hour and a half.After cooling,8 mL water and 5 mL petroleum were added and shaked strongly and the ethereal layer was separated in a dry tube,evaporated to dryness.The fatty acid methyl esters were analyzed by using a Hewlett Packard(HP 6890)chromatography,a split/splitless injector and flame ionization detector.Results:In female R.sarba,a total of 29 fatty acids were detected in ovaries throughout the spawning season.The main fatty acid group in total lipid was saturated fatty acid(SFA,28.9%),followed by 23.5%of polyunsaturated fatty acids(PUFA)and 12.9%of monounsaturated fatty acids(MUFA).The dominant SFA were palmitic and stearic,the major MUFA were palmitoleic and oleic,and the major PUFA were C18:2 and C22:2.During spawning stages,there were no significant differences in total SFA,MUFA and PUFA.The highest value of SFA was in late spawning(36.78%).However,the highest value of MUFA and PUFA was in spawning(16.70%and 24.96%respectively).During spawning season there were significant differences in total SFA between March(late spawning stage)and December(nearly ripe stage),P<0.05.Conclusions:From the present study it has been shown that 29 fatty acids were detected in ovaries of R.sarba throughout the spawning season.The main fatty acid group in total lipid was SFA followed by PUFA and MUFA.The dominant SFA were palmitic and stearic,the major MUFA were palmitoleic and oleic,and the major PUFA were C18:2 and C22:2.The highest value of SFA was in late spawning.However,the highest value of MUFA and PUFA was in spawning.

余氯对大亚湾海区平鲷和黑鲷幼鱼的毒性研究

用含游离余氯、化合余氯的海水分别对大亚湾平鲷Rhabdosargussarba、黑鲷Sparusmacrocephalus浸毒处理30min和60min。结果表明，两种形态余氛对色的耗氧率有明显抑制作用，游离余氯对平鲷、黑鲷的48hLC50分别为0．19和0．18mg·L－1，48hLC1分别为0．07和0.06mg·L－1；化合余氯的48hLC50分别为0.56和0．60mg·L－1，48hLC1分别为0．21和0．24mg·L-1。游离余氯的毒性大约是化合余筑的6倍。游离余氯、化合余氯安全阈限估算值分别为0．09和0．28mg·L－1，稍高于48hLC1。