Muscle protein expression of pikeperches (Stizostedion lucioperca and S. volgense)

The purpose of the present study was to investigate the muscle protein expression in two pikeperches(Stizostedion lucioperca and S.volgense)through intra-and intermyomeric composition of white muscles.Using denaturing 10%sodium dodecylsulfate-polyacrylamide gel electrophoresis,muscle protein expression was studied in relation to within-and between-species morphological development,sex,maturity and age of pikeperches.Myosin,actin and troponin have a distinct role in the contraction and length tension of muscle fibers of these species.No obvious intramyomeric differences were found in the myosin heavy chain of both species.Myosin light chains(15-38 kDa)have different expression in different age groups.The muscle protein of the fingerling and adult S.lucioperca had high molecular weight(50 kDa)myosin in contrast to the other Percid species.The molecular weight of actins increased comparatively in low-age-group fish.ATP is stored in myosin and released to cause contraction when myosin comes in contact with actin of the experimental fish.Troponin regulates increasing concentration of lightchain myosin in mature fish.Because troponin T has been implicated in the regulation of skeletal muscle kinetics,muscle contraction kinetics was predicted in different age groups.The muscle proteins of both sexes of these species have polymorphism in various age groups but have no difference in similar aged fish.No muscle protein dimorphism was found in these Percid species.The white muscle protein composition and contractile properties affect power production during fast,unsteady movement and swimming.

大眼鰤鲈鱼的长途运输

１９９３年５月２４日从加拿大萨斯卡切温省环境及资源管理Ｆｏｒｔ所属ＦｏｒｔＱｕ，ＡＰｅｌｌｅ鱼苗孵化场移运大眼 鲈发眼鱼卵１００万粒，鱼苗４万尾，采用尼龙袋充氧气，低温保存等方法，途经４４小时的长途空运，到哈尔滨市水产研究所，发眼鱼卵运输成活率４０％，鱼苗运输成活率９０％。

Heavy metal levels in the liver and muscle tissues of the four commercial fishes from Lake Balik,Kızılırmak Delta(Samsun,Turkey)

Objective:To determine the levels of some heavy metals in the liver and edible tissues of four fish species[Mugil cephalus L.,1758(M.cephalus),Cyprinus carpio L.,1758(C.carpio),Perca fluviatilis L.,1758(P.fluviatilis)and Stizostedion lucioperca L.,1758(S.lucioperca)]collected from Lake Balik,Kizilirmak Delta(Samsun)for analysis of Cu,Co,Pb,Zn,Cd,Mn,Ni and Fe.These metals were chosen because at higher concentrations there might be toxic to the fish and by extension humans that depends on such fish as food.Methods:The concentrations of the metals were carried out by the flame atomic absorption spectrophotometer(UNICAM 929).Results:Large differences in heavy metal levels were observed between liver and muscle tissues within each fish.The results showed that the Fe concentrations were the highest and Cd concentrations were the lowest in livers and edible tissues of the four species.The muscles of C.carpio accumulated significant higher levels of Co,Zn and Ni than other species.Cu was higher in the muscles of S.lucioperca than those in other species,while M.cephalus showed more of Mn and Fe levels.The muscles of P.fluviatilis accumulated significant higher levels of Pb and Cd than other species.However,the liver of M.cephalus accumulated significant higher levels of Co,Mn and Fe than other species.The level of Cd was the highest in the liver of P.fluviatilis,while S.lucioperca showed more of Cu and Pb,and the higher levels of Zn and Ni was measured in the liver of C.carpio.Conclusions:The metal levels obtained were compared with the maximum permitted levels in food of the Turkish Food Codex and Commission Regulation(EC).The results of this study showed that estimated daily and weekly intakes of selected metals via consumption of fish were below the permissible tolerable daily intake and provisional tolerable weekly intake values established by Food and Agriculture Organization/World Health Organization.