肉碱对草鱼代谢强度的影响

采用腹腔法注射肉碱,分别测定了D-型、L-型和DL-型3种构型的肉碱对草鱼鱼种耗氧率的影响,以探讨草鱼对3种构型的肉碱代谢强度的差异.试验结果表明(1)注射100×10-6D-型、100×10-6L-型和100×10-6,200×10-6DL-型3种构型的肉碱.注射后0.5h,草鱼耗氧率均达到最大,随着时间的延长耗氧率逐渐下降.D-型和L-型肉碱在注射后3h草鱼耗氧率恢复至正常水平,DL-型在5h后也恢复至正常水平.其作用效果为L-型>D-型>DL-型.(2)分别注射D-型、L-型和DL-型各4个剂量水平(50×10-6,100×10-6,150×10-6和200×10-6).注射后0.5h,D-型和L-型均在100×10-6剂量水平耗氧率达到最大,而DL-型在150×10-6达到最大值,表明肉碱对草鱼的有效剂量为100×10-6～150×10-6.上述结果表明3种构型的肉碱均对草鱼产生了生理作用,使草鱼的代谢强度--耗氧率增加,其增加的强度与肉碱的构型有关.

EFFECTS OF CARNITINE ON METABOLIC RATE IN GRASS CARP ( CTENOPHARYGODEN LDELLUS)

Carnitine of different conformations (D-carnitine 0.01%, L-carnitine 0.01%, or DL-carnitine 0.01% or 0.02%) were injected into the abdominal cavity of grass carp and oxygen consumption of the fish was recorded. Half an hour after the injection, oxygen consumption rate increased to the maximum in all the treatments, and decreased gradually thereafter. Oxygen consumption was restored to the normal rate 3 hours after the injection of D- or L-carnitine and 5 hours after DL-carnitine injection. The magnitude of the effect appeared in the order of L-carnitine > D-carnitine > DL-carnitne. In another experiment, 4 dosages (0.005%, 0.01%, 0.015% and 0.02%) were adopted for each of the three carnitines. As determined half an hour after the injection, oxygen consumption rate reached the maximum in the treatments of 0.01% for D-carnitine and L-carnitine and in the treatment of 0.015% ppm for DL-carnitine, suggesting that the effective dosage of carnitine for grass carp ranged from 0.01% to 0.015% ppm. It is concluded that carnitine of all the three conformations studied exerts a physiological effect on grass carp, resulting in an increase of its oxygen consumption rate an index of metabolic strength, and that such an effect varies with the conformation of carnitine.