Effect of temperature and diet on gastrointestinal evacuation of juvenile malabar blood snapper (Lutjanus malabaricus Bloch & Schneider, 1801)

Abstract

Temperature- and prey-specific gastrointestinal evacuation times and gastrointestinal emptying rates were estimated for Lutjanus malabaricus under laboratory condition by using X-radiography and serial slaughtering techniques. Fish were collected from Pulau Ketam, Selangor, Peninsular Malaysia and subjected to four different experimental temperatures (22 °C, 26 °C, 30 °C and 34 °C) and two different types of feeding (pellet diet or shrimp (Acetes sp.)). The results of X-radiography and serial slaughtering showed that the initial voidance of faecal matter began 4–8 h after feeding at all temperatures. The fastest gut emptying time and rates were seen in the 30 °C group fed with shrimp diet (16 h), where the proportion of meal remaining in the stomach decreased from 100% to less than 8% after 12 h of starvation. A significant delay in gut emptying was observed in the 22 °C group fed with formulated pellet diet (28 h). The best performance was observed at 30 °C group fed with shrimp diet. L. malabaricus fish mass (W, g) was also incorporated into a modified square root model, which fitted the wet mass gut evacuation data obtained by the serial slaughtering method regardless of temperature and prey type (adjusted r2 > 0.99). The results of this study suggested that L. malabaricus should be cultured in 30 °C and fed with shrimp diet to optimize its commercial production and condition.