The routine metabolic rate in southern catfish juvenile(24.3-250.8 g)fed with saccharine feed(CHO)was measured in this study.Fish were fed with iso-nitrogenous(40 % crude protein)and iso-lipidic(10% crude lipid)experimental feed containing 0(control feed),15%,30% of carbohydrate level.The routine metabolic rates of 15 % and 30% dietary carbohydrate group were significantly higher than that of 0% dietary carbohydrate group.The relationship between body mass(Wt)and routine metabolic rate(Rr)of southern catfishfed with different test feed could be described as:(1)0% CHO:ln(Rr)=0.986 ln(Wt)+1.419 r2=0.922,n=25,P<0.001;(2)15% CHO:ln(Rr)=0.912 ln(Wt)+1.741 r2=0.966,n=21,P<0.001;(3)30% CHO:ln(Rr)=0.762 ln(Wt)+2.378 r2=0.958,n=21,P<0.001.The intercept was increased and mass coefficient was decreased with the increase of carbohydrate level in feed.It could be concluded that southern Silurus meridionalis had poor metabolic capacity which led the increase of routine metabolic rate of fish with small size.But with the increase of body size southern Silurus meridionalis might had a better adaptation to high carbohydrate concentration.
The objective of the study was to explore the effect of acute low temperature stress on VO2 and Vf of Silurus meridionalis and Pelteobag vachelli after 10 minutes cold water bath with different temperature.The investigation was operated under the temperature of 24 ℃.It was found that the VO2 and Vf of Silurus meridionalis after 6 and 0 ℃ stress showed a decrease-increase-decrease trend while other groups showed a rapid increase then slowly recovery trend.The VO2 and Vf of Pelteobag vachelli after 0 ℃stress showed a decrease-increase-decrease trend while other groups showed an increase then slowly recovery process.It was suggested that Pelteobag vachelli was more adaptive to acute cold stress,but it cost more energy adapting to cold stress compared to Silurus meridionalis.
