Physiological energetics of Cherax quadricarinatus (von Martens) feed with two diets and exposed to constant and fluctuating temperatures

Abstract

The energy budget of the redclaw juveniles Cherax quadricarinatus feed with two diets (Rangen with 35% protein and Purina with 32%) was determined. The organisms were exposed to two regimens of temperature, constant 28 ºC and fluctuating 25-33 ºC. The highest energy from the food consumed by the organisms was obtained from the fluctuating regime of temperature and the Rangen diet. The oxygen consumption routine of the redclaw juveniles fed with both diets and exposed to the fluctuating temperature regime was 3.5 to 7.1% less than the organisms acclimated to the constant temperature regime. In the crayfish maintained with the fluctuating temperature regime the apparently heat increase (AHI) caused by the food ingestion was the lowest value. The high quantity of potential energy derived to the scope for growth (1949 Joules g-1 day-1 d.w.) was obtained in the juveniles of redclaw fed with the Rangen diet and the fluctuating regime. With the results obtained in this study we recommended in order to optimize the redclaw crayfish culture (Cherax quadricarinatus) in controlled conditions, to use a similar diet, which has the nutrients as Rangen. Also the organisms to be maintained in a fluctuating temperature regime because the exposition to this cycle allows maximizing the energy, which the crayfish will canalize for the scope of growth.