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| Biochemical Changes and Energy Utilization during Embryonic Development and Metamorphosis in Hard Clam Mercenaria mercenaria |
| XIA Chang-ge,LI Xiao-xu,SONG Jian,CHANG Ya-qing |
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Abstract The levels of protein , total lipid and carbohydrate and energy utilization were studied in fertilized eggs , D-shaped larvae , and premetamorphic , and postmetamorphic larvae of hard clam (Mercenaria mercenaria) .The results showed that the fertilized eggs was composed of 47 .6% protein , 42 .2% lipid ,and 10 .2% carbohydrate ,with average energy of 0 .988 mJ per egg .Twenty-four hours after fertilization ,there were decrease in approximate composition at a rate 12 .5% of protein ,18 .8% of lipid , 13 .9% of carbohydrate ,and 15 .3% of energy per egg .During embryonic development ,total energy of 0 .161 mJ was expended by an embryo ,in which 26 .0% derived from protein ,68 .5% from lipid ,and 5 .4% from carbohydrate .During the metamorphosis , 25 .1% protein , 26 .6% lipid , and 19 .2%carbohydrate were exhausted by the larvae ,2 .111 mJ individually ,accounting for 44 .4% in protein , 35 .9% in lipid and 19 .2% in carbohydrate .The energy consumption was found in the metamorphosis as 13 times as in the embryogenesis .
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Received: 25 December 2013
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