水温骤降和缓降胁迫对褐篮子鱼血液生理生化指标的影响

为探讨水温骤降和缓降胁迫对褐篮子鱼Siganus fuscescens血液生理生化指标的影响,水温骤降试验以24℃为对照,将体质量为(37.12±5.60)g的试验鱼由24℃直接浸入20℃海水中,适应1 h取样,维持24 h后将剩余试验鱼浸入16℃海水中适应1 h取样,以此类推直到水温降至8℃维持1 h取样;水温缓降试验水温由24℃按1℃/3 h的降温速度降至20℃,维持3 d取样,以此类推直到水温降至8℃维持3 d取样,并测定试验鱼血液的各种生理生化指标。结果表明:在水温骤降试验中,试验鱼血液中红细胞(RBC)、血红蛋白(HGB)、红细胞压积(Hct)在8℃时均显著降低(P0.05);谷丙转氨酶(ALT)和碱性磷酸酶(AKP)活力均呈先升后降的趋势,ALT活力除20℃时外,其他控温点均显著高于对照组(P0.05),AKP活力在20℃时显著升高;谷草转氨酶(AST)活力呈波动变化,在各控温点均显著升高(P0.05);血清葡萄糖(GLU)含量在8℃时显著升高,在其他控温点均显著低于对照组(P0.05);胆固醇(CHOL)、总蛋白(TP)、白蛋白(ALB)含量除20℃时外,其他控温点均显著低于对照组(P0.05);甘油三酯(TG)含量在20℃时显著升高,在其他控温点均显著低于对照组(P0.05);肌酐(CREA)含量在20℃时显著升高(P0.05)。在水温缓降试验中,试验鱼血液中RBC、HGB显著降低(P0.05),其余指标均无显著性差异(P0.05);ALT活力在12℃时显著升高并达最大值,AST活力在20、12℃时显著升高,AKP活力除16℃组外均显著高于对照组(P0.05);GLU含量在8℃时显著升高,CHOL含量在16、12℃时显著低于对照组(P0.05),TG、TP和CREA均呈先升高后降低的趋势,不同之处是TP含量不能恢复至初始水平;ALB含量除20℃时外,其他控温点均显著低于对照组(P0.05)。研究表明,在本试验条件下,褐篮子鱼能够存活的最低温度为12℃,8~9℃是褐篮子鱼的致死温度下限。

Effects of abrupt and gradual decreases in water temperature on blood physiological and biochemical parameters in dusty rabbit fish Siganus fuscescens

In this study, hematology and serum biochemical parameters were investigated in dusty rabbit fish Siga-nus fuscescens with body weight of (37. 12±5. 60)g exposed to abrupt (24 ℃ in control group --20 ℃--16 ℃--8 ℃,sampled in 1 h acclimatization) and gradual (24 ℃ in control group --20 ℃--8 ℃ at a rate of 1 ℃/3 h, sampled in 1 h acclimatization) decreases in water temperature. The results showed that the number of red blood count ( RBC) , hemoglobin ( HGB) , and hematocrit ( Hct) in hematology were significantly decreased at 8 ℃, in the abrupt decrease temperature groups, with first increase-then decrease in activities of glutamyl- transpeptidase ( ALT) and alkaline phosphatase ( AKP) . There was significantly higher ALT activity than that in control group ex-cept in group 20 ℃, with significantly higher AKP activity at 20 ℃ (P<0. 05). Glutamate-oxaloacetate (AST) activity was shown to be a fluctuation tendency, significant increase from the initial level (P<0. 05). Glucose ( GLU) concentration in serum was significantly increased at 8 ℃, while significantly lower in the other tempera-ture treatments than the initial level ( P<0 . 05 ) . There was significantly lower concentrations of cholesterol ( CHOL) , total protein ( TP) and albumin ( ALB) in the other temperature except for 20 ℃ than those in the con-trol group. The triglyceride ( TG) and creatinine ( CREA) concentrations were significantly increased at 20℃, sig-nificantly lower TG at the other temperature than the initial level ( P<0 . 05 ) . In gradual decrease in water tempera-ture, however, RBC and HGB were decreased significantly (P<0. 05), without significant differences in the other hematology parameters ( P>0 . 05 ) . There were significantly higher ALT activities at 12 ℃ than those in the control group, and significantly higher AST activities at 20 ℃ and 12 ℃ than those in control group. It was found that AKP activities were significantly increased in all groups except for at 16℃ ( P<0 . 05 ) . GLU concentration was sig-nificantly increased at 8 ℃, and CHOL concentration significantly decreased at 16 ℃ and 12 ℃( P<0 . 05 ) . The concentration of TG, TP and CREA showed a increase-decrease trend, the TP concentration being not recovered to the initial level. ALB concentration was significantly decreased compared to the initial level except for at 20℃( P<0 . 05 ) . The findings suggest that dusty rabbit fish have lower limit temperature for survival at 12℃, and lethal low temperature of 8-9 ℃.