Influence of seasonal temperature on the repeat swimming performance of rainbow trout Oncorhynchus mykiss.

摘要: While the temperature dependence of exercise performance in fishes is reasonably well documented, information on metabolic recovery and reperformance scant. This study examined swimming after exhaustive rainbow trout Oncorhynchus mykiss at seasonal temperatures ranging from 5 to 17 degrees C explored relationship between preceding state. The primary objective was test hypothesis that increased increases capability repeat a critical speed (U(crit)), as assessed by two consecutive tests separated 40 min rest interval. An additional expectation certain plasma ionic, humoral parameters would be correlated with how fish reperformed so levels lactate, potassium, ammonia, osmolality, sodium cortisol, hematocrit, were monitored before, during swim challenges via an indwelling cannula dorsal aorta. As expected, first U(crit) (U(crit1)) positively related temperature. However, U(crit1) (U(crit2)) not dependent acclimation simple manner. Contrary our expectations, U(crit2) less than for warm-acclimated (14.9+/-1.0 C), whereas equaled cold-acclimated (8.4+/-0.9 C). Cold-acclimated also exhibited lower disruption compared fish. Thus, while warm conferred faster U(crit1), similar could attained subsequent period. finding does support ability reperform improved Both lactate potassium strongly performance. Therefore, higher may have been due part greater anaerobic effort In fact, significant correlation existed concentration prior start second performance, such decreased when threshold level around 12.2 mmol l(-1) surpassed initial swim. No other measured variable showed We conclude fish, apparently harder possibly more anaerobically unable sufficiently fixed period this poorer elevations levels.