Triploidy affects postprandial ammonia excretion but not specific dynamic action in 1+ brook charr, Salvelinus fontinalis

Abstract The use of sterile triploids in aquaculture is currently limited because of reduced performance in situations of aerobic stress such as high temperature, hypoxia, and exhaustive exercise. Many studies have therefore attempted to find underlying metabolic differences between triploids and their diploid counterparts to improve triploid rearing protocols. This study investigated the effects of triploidy on postprandial metabolism (and therefore also pre-feeding standard metabolic rate; SMR) in 1+ (193 ± 5 g; mean ± SE) diploid and triploid brook charr, Salvelinus fontinalis. Oxygen uptake and total ammonia nitrogen (TAN) excretion were measured at 14–15 °C for previously fasted (for eight days) fish from 48 h before to 48 h after being sham fed or fed a single ration of 0.4% of their body mass. While there were no ploidy-related differences in SMR or any of the measured SDA parameters, triploids had significantly higher net TAN excretion (by 36%) than diploids. Such a difference in protein metabolism could affect triploid growth and survival when simultaneously faced with suboptimal conditions, though further studies are warranted.