Cross Effects of Diets and Rearing Temperatures on Gastrointestinal Evacuation and Growth Performance in Adult Sabah Groupers (Epinephelus fuscoguttatus × E. lanceolatus)

SIMPLE SUMMARY: The commercially popular Sabah grouper has gained attention due to its high growth rate. Our preliminary study briefly reported how temperature and diet affect gastric emptying time and specific growth rate of hybrid Sabah grouper; however, a comprehensive study on gastrointestinal evacuation GE (Gastrointestinal time together with gastric emptying rate) of adult hybrid Sabah grouper at different temperatures and diets has yet to be conducted. In this follow-up study, we suggest that the optimum temperature and feed for adult Sabah grouper are 30 °C and trash fish, respectively. ABSTRACT: This study explores the gastrointestinal evacuation time (GET) and gastrointestinal evacuation rate (GER) of the popular Sabah grouper (Epinephelus fuscoguttatus × E. lanceolatus) adults using two established methods (X-radiography and serial slaughter) and square root modeling using different temperatures: 28 °C, 30 °C, 32 °C, and 34 °C and different diets: pellet (ash: 11.4 ± 0.08; moisture: 29.0 ± 0.01; protein 37.5 ± 0.80; lipid 15.0 ± 0.13) and trash fish: Sardinella sp. (ash: 2.3 ± 0.15; moisture: 78.5 ± 0.33; protein 55.4 ± 0.62; lipid 7.3 ± 0.25) and the impact on growth indices. The results indicate that the GET shortened as temperature increased from 28 °C to 30 °C; however, it was prolonged when it surged to 32 °C and 34 °C. The groupers fed with trash fish at a temperature of 30 °C had the shortest GER (0.41 ± 0.10 g hr(−1)) whereas groupers fed with pellet at 34 °C had the longest GER (0.95 ± 0.02 g hr(−1)). Likewise, the highest SGR (16.25 ± 2.11% day(−1)) was observed at 30 °C for groupers fed with a trash fish diet. The condition (K) value was lowest at 34 °C for groupers fed with a pellet diet (1.01 ± 0.04) and highest at 30 °C for groupers fed with trash fish (1.45 ± 0.04). Our results suggest that temperature and diet influence growth indices and GE of adult Sabah groupers. Incorporation of this information will allow better management of this commercially important grouper species when reared in a controlled aquaculture environment.