| Southern catfish (Silurus meridionalis), a warmwater and scaleless fish, were chosen as the experimental animal. oxygen(O2) uptake across the skin (MO2skin) and gills (MO2gill) of juvenile southern catfish in conditions of different acclimation temperature (10,20 and 30℃) and acute temperature change (10→20℃, 20→30℃, 10→30℃and 20→10℃, 30→20℃, 30→10℃) were measured simultaneously with the respirometer designed by ourselves, fishes in this experiment were anaesthetized and we got the total O2 uptake rate (MO2total) with MO2skin plus MO2gill. The aim of this study were to examined and comparaed the effects of acclimation temperature and acute temperature change on MO2skin and MO2gill of juvenile southern catfish respectively, and hence to investigate the temperature responses of cutaneous respiration in fishes and provide basic information for the energy metabolism of fish physiology researchThe results as follows:1. cutaneous O2-uptake in different acclimation temperature (10, 20, 30℃) of juvenile southern catfish was 12.83±0.70,18.20±0.97,22.65±2.07 mgO2/h/kg respectively, cutaneous O2-uptake of acclimation groups made up 16.4-19.0 % of total uptake.2. With acclimation temperature rised, the cutaneous O2-uptake of 20℃acclimate group was significant greater than 10℃and there was no significant difference between the MO2skin of acclimation temperature (20 and 30℃) groups (P>0.05). The effect of acclimation temperature on cutaneous O2-uptake was significantly different from total O2-uptake (P<0.05), MO2skin increased less than MO2total significantly (P<0.05) with acclimation temperature rised (P<0.05). then the contribution of MO2skin to MO2total have a declining trend. 3. The cutaneous O2-uptake of acute temperature elevation (decline) groups significantly increased (decreased) compared to the acclimation groups before acute temperature elevation (decline) (P<0.05), The MO2total of acute temperature elevation (decline) groups yet significantly increased (decreased) compared to the acclimation groups before acute temperature elevation (decline) (P<0.05), but the average value of Q10 for MO2skin was significantly lower than that of MO2total (P<0.05).4. The cutaneous O2-uptake of acute temperature change groups were not different from corresponding acclimation groups (P>0.05), there were not significant difference between the average values of Q10 for MO2skin in acute temperature change groups and acclimation groups (P>0.05), but The MO2total of acute temperature change groups were higher than corresponding acclimation groups (P<0.05), the average values of Q10 for MO2total in acute temperature change groups were higher than that of acclimation groups too.The indications as follows:1. It was demonstrated that cutaneous oxygen uptake of southern catfish was existed. Compared to others and we discovered that the level of MO2skin contributed to MO2total was better than average.2. MO2skin of juvenile southern catfish increased considerable slowly, the effect of acclimation temperature on MO2skin was significantly lower than that of MO2total, MO2skin keep relative stability when MO2total changed in a big extent with acclimation temperature rised.3. The effect of acute temperature change on MO2skin distincted from that of MO2total , acute temperature change made MO2total varied more rapidly than acclimation temperature, but MO2skin still keep relative stability. 4. This study indicates that the fish existed metabolic compensation and acute response respectivey corresponding to acclimation temperature and acute temperature change, compared with total O2-uptake, cutaneous O2-uptake was neither a chemical react process nor a biological response, but tend to a process correlated with physical perfusion.
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