恒温和变温下中国对虾生长和能量收支的比较

A comparative study on the growth and energy budget of Chinese shrimp (Fenneropanaeus chinensis Osbeck) at constant and diel fluctuating temperature

对比研究了模拟自然昼夜温度变化节律的4个变温(22±2)、(25±2)、(28±2)和(31±2)℃与相应的恒温22、25、28和31℃下中国对虾(F ennerop enaeus ch inensis O sbeck)生长和能量收支的差异。结果表明,对虾在(22±2)℃、(25±2)℃和(28±2)℃变温条件下的生长率显著高于相应的恒温,但(31±2)℃与恒温31℃相比没有显著差异。与相应的恒温相比,(25±2)℃、(28±2)℃和(31±2)℃变温下对虾的摄食量显著增大,(22±2)℃、(25±2)℃和(28±2)℃变温下对虾的饵料转化率则显著提高。但变温下对虾对食物的消化率与相应的恒温相比没有显著差异。能量收支研究结果则发现,(22±2)℃、(25±2)℃和(28±2)℃变温下对虾摄食能中,用于生长的能量比例显著增加,而(31±2)℃与31℃相比则未见显著差异。从而表明,变温促长的主要机制可归因于变温下摄食量的增大、饵料转化率的提高及其摄食能中用于生长能比例的增加。

Temperature fluctuates diurnally and seasonally in natural aquatic systems. However, most previous studies on the effects of temperature on the growth of Chinese shrimp （Fenneropenaeus chinensis Osbeck） usually were conducted at constant temperature with a assumption that growth at a constant temperature is close to that at fluctuating temperature with a mean similar to the constant one. Current literature on the effect of fluctuating temperature on the growth of Chinese shrimp is fragmental.. The growth rate, food consumption, food conversion efficiency and energy budget of Chinese shrimp were compared between diel fluctuating temperatures （（22 ± 2）, （25 ±2）, （28 ± 2） ℃and （31±2） ） and constant temperatures （22, 25, 28℃, and 31℃）. This study further explored the physiological and bioenergetic mechanisms involved to optimize shrimp growth in thermally fluctuated regimes. The range and pattern of temperature fluctuation mimicked those found in north China （36°1′ N, 120°3′E） during the growth season. The minimum temperature was set at 0600 hours, and then gradually increased to the maximum value at 1400 hours. Upon reaching the maximum, the temperate was decreased to the minimum at 0600 hours next day before repeating the diel cycle. Shrimp were cultured in glass aquaria （45cm× 25cm×30 cm） which were immersed in one water bath tank （170cm × 75cm× 30 cm） for each temperature treatment and the temperature change in the aquaria was synchronized with each water bath. There were five shrimp in each aquarium with four replicates. The whole experiment lasted for 33 days. The results showed that the growth rates of shrimp at diel fluctuating temperatures of （22±2）, （25±2）℃ and （28±2）℃ were significantly greater than those at constant temperatures of 22, 25, 28, and 31℃,respectively. However, no significant difference was found between （31± 2）℃ and 31℃. The food consumption at （25 ± 2）, （28＋2）℃ and （31±2）℃ were significantly higher and the food conversion efficiency at （22±2）, （25±2）℃ and （28±2）℃ compared to those at the corresponding constant temperatures. No significant difference in apparent digestion rate was found between the constant and diel fluctuating temperatures. The energy budget analysis showed that the energy assimilated into growth as a percentage of energy intake at fluctuating temperatures of （22 ± 2）, （25 ± 2）℃ and （28± 2）℃ was significantly higher than that at the corresponding constant temperatures, while no significant difference was found between 31℃ and （31± 2） ℃. Therefore, the enhancement of shrimp growth could mainly be ascribed to high energy intake, high food conversion efficiency and more energy partitioned into growth.