不同摄食水平条件下鮻的碳收支研究

Carbon Budget of Redlip Mullet(Liza haematocheila T.& S.) Under Different Feeding Rates

在水温20℃和盐度30的条件下研究摄食水平对碳收支的影响。摄食水平分为饥饿(不投喂)、1、2、3、4(指日摄食量占鱼体重百分比)和自由摄食共6组,实验持续21 d。结果表明:摄食水平对碳消化率没有影响。碳转化率、净生长率与摄食水平之间呈显著正相关关系,在自由摄食状态下分别达到9.29%和10.41%。非粪便流失碳随摄食水平增加而显著降低。粪便碳占摄入碳比例变化不大,与摄食水平间无规律性关系。在自由摄食状态下,大部分摄入碳量均通过非粪便途径流失,其中大部分是呼吸过程消耗的。余下的部分中,粪便流失量和鱼体保存量各占一半。鱼体每增长1 g体重伴有979.56 mg碳流失。在自由摄食状态下碳收支方程式为:100摄入碳=9.29生长碳+9.69粪便碳+79.94非粪便流失碳。

Carbon budget of redlip mullet influenced by feeding rates was researched in the condition of water temperature 20 ℃ and salinity 30. Six feeding rates were set as follows： starvation, 1,2, 3, 4 （percent of body weight） and voluntary feeding. The experiment lasted 21 days. The results showed that feeding rate did not influence carbon digestion rate. The carbon conversion rate and net growth rate were positively related with feeding rate, and reached their peaks at 9.29% and 10.41% for the voluntary feeding group. The non-faecal loss carbon decreased with increasing feeding rate. The faecal carbon changed little with different feeding rates, showing an irregular relationship between them. With voluntary feeding, most intake carbon was lost through non-faecal way （e. g. respiration）, and the rest was divided into faeces and growth evenly. With 1 g fish body weight gain, there was 979.56 mg carbon losing. The carbon budget of redlip mullet feeding voluntarily was 100 intake carbon = 9.29 growth carbon ＋ 9.69 faecal carbon ＋ 81.03 non-faecal loss carbon.