Effects of temperature on the SDA of the brook trout

Abstract

Specific dynamic action (SDA), the metabolic phenomenon resulting from the digestion and assimilation of a meal, is generally influenced by temperature. The effects of temperature (5.5±0.5, 8.5±0.5, 11.5±0.5, 14.5±0.5, 17.5±0.5°C) on SDA of brook trout (Salvelinus fontinalus Mitchill) was evaluated, by measuring the temporal pattern of the oxygen consumption rates, after feeding. Peak VO 2 (highest recorded oxygen consumption rate following feeding) and SDAE (energy expended on SDA) increased slowly to a maximum at 14.5±0.5°C, and then decreased at 17.5±0.5 °C. The relationships between Peak VO 2 (mg·kg−1·h−1), the SDA E (kJ·kg−1) and temperature (t, °C) were respectively described as: Peak VO 2 = −0.1332t4 + 5.6612t3 −86.317t2 + 581.33t − 1275.3, SDA E = −23.59t4 + 999.28t3 − 15303t2 + 101913t − 229665 (n=650, R2 = 1, 4.5<t<17.5). The results of Peak VO 2 and SDA E showed that the optimum growth of brook trout occurred at 14.5±0.5□. Duration decreased from 28±0.7h to 16±0.6h as the temperature increased from 5.5±0.5 to 17.5±0.5°C. The relationship between duration (h) and temperature (t, °C) was described as: duration = −0.0051t4 + 0.2305t3 − 3.767t2 + 25.724t −33.167, (n=650, R2 = 1, 4.5<t<17.5).