半粗放的飼育条件下におけるマダイ幼魚の食性と体成分

高知県栽培漁業センターの半粗放的飼育池におけるマダイ幼魚の食性と体成分を調査し、次の知見を得た。1) 飼育池でのマダイ幼魚の食性は、調査日によって天然餌料依存型と人工飼料依導型に大別され、天然餌料に依存した食性を示した群の胃充満度は、人工飼料に依存した群に比べて低い傾向にあった。2) 筋肉中の一般成分は中間育成期間中ほとんど変化しなかったが、その後は筋肉および腹腔内脂肪組織の脂質クラス組成におびてトリグリセライドの比率が著しく増加した。

Stomach content and body constituent of the larval red sea bream were examined at the large pond of Kohchi Fish Farming Center. The fish was semi-extensively reared by the supply of artificial diet in addition to natural organisms and ranged from 8.2 to approximately 50 mm. 1) In the food composition, either natural organisms such as Copepoda or artificial diet was predominant at each sampling date. Stomach fullness of the fish feeding mainly on the former was higher as compared with the fish depending on the latter. 2) The proximate composition of muscle hardly changed during the rearing period. But thereafter the lipid class of muscle and intraperitoneal fat body exhibited a remarkable change, particularly an increase in the ratio of triglycerides.