温度对不同规格珍珠龙胆石斑鱼(棕点石斑鱼♀×鞍带石斑鱼♂)呼吸和排泄的影响

应用实验生态学方法,研究了不同水温(15.8℃、21.0℃、26.6℃、30.9℃、36.5℃)对小(28.1?1.1)g]、中(278.9?20.1)g]、大(575.8?37.4)g]3种规格的珍珠龙胆石斑鱼(棕点石斑鱼♀×鞍带石斑鱼♂)(Epinephelus fuscoguttatus♀×Epinephelus lanceolatus♂)呼吸和排泄的影响。实验结果表明,温度和规格对珍珠龙胆耗氧率和排氨率的影响均达到显著水平(P0.05);小、中、大3种规格珍珠龙胆耗氧率和排氨率随水温的增加呈现先升高后降低、再升高的变化规律,当水温为26.6℃时达到最大值,分别为(1.510±0.124)mg/(g·h)、(0.306±0.007)mg/(g·h)、(0.161±0.010)mg/(g·h)和(47.739±21.048)μg/(g·h)、(13.956±1.783)μg/(g·h)、(6.811±1.882)μg/(g·h),耗氧率和排氨率与温度之间的回归关系均符合一元四次方程,相关系数R2均为1.000。在水温15.8~36.5℃范围,相同水温下,珍珠龙胆的耗氧率和排氨率随其个体的增大而降低,耗氧率和排氨率与规格之间的回归关系均符合一元二次方程,相关系数R2均为1.000。不同温度条件下,小、中、大3种规格珍珠龙胆的耗氧率Q10和排氨率Q10在21.0~26.6℃时均达到最大,且其均在26.6~30.9℃时最小。小、中、大3种规格O/N比值平均值变化范围分别为21.535~113.541、15.713~32.193、12.097~27.094,表明实验水温条件下小规格珍珠龙胆的供能物质为蛋白质、脂肪和碳水化合物,而中、大规格珍珠龙胆的主要能量物质为蛋白质和脂肪。

Effects of temperature on respiration and excretion by different sizes of hybrid grouper (Epinephelus fuscoguttatus♀×Epinephelus lanceo-latus♂)

The effects of five water temperatures (15.8℃, 21.0℃, 26.6℃, 30.9℃, 36.5℃) on respiration and ex-cretion in three sizes (27.4 g±0.8 g, 276.5 g±17.3 g, and 575.4 g±18.8 g) of hybrid grouper (Epinephelus fus-coguttatus♀×Epinephelus lanceolatus♂) were investigated using ecological methods in the laboratory. The ex-perimental results showed that both water temperature and body weight had significant effects on oxygen con-sumption and ammonia excretion rates of hybrid grouper (P<0.05). Under controlled laboratory conditions, oxy-gen consumption and ammonia excretion rates increased initially in all sizes of hybrid grouper, then decreased and increased again as water temperature was increased. These rates were highest at 26.6℃, such as (1.510±0.124) mg/(g·h), (0.306±0.007) mg/(g·h), and (0.161±0.010) mg/(g·h) and (47.739±21.048)μg/(g·h), (13.956±1.783)μg/(g·h), and (6.811± 1.882)μg/(g·h), respectively. The regression equations between oxygen consumption rate and ammonia excretion rate and water temperature were quadratic (R2=1.000). Oxygen consumption and ammonia excretion rates within the temperature range of 15.8–6.5℃ decreased roughly with an increase in body weight at the same water temperature, and the regression equations for oxygen consumption rate mg/(g·h) and ammonia excretion rateμg/(g·h)and body weight were quadratic (R2=1.000). TheQ10 values for the oxygen consumption and ammonia excretion rates in all sizes of hybrid grouper peaked at water temperatures of 21.0–26.6℃ and were at their mini-mum at 26.6–30.9℃. The mean O/N ratios of the small- and medium- and large-sized hybrid grouper were 21.535, 15.713, and 12.097 to 113.541, 32.193, and 27.094, respectively, indicating that protein, fat, and carbohydrate wereconsumed by the small-sized hybrid grouper for energy, and that protein and fat were consumed by me-dium-and large-sized hybrid grouper.