Allen Michael Gurrea, Annia Rae Nicolasora, Hannah VAlencia (January 2003)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
Gastric evacuation rates and intestinal passage of food in relation to time in tilapia (Tilapia nilotica) reared at different salinities were evaluated. Tilapia broodstock(approximately 200g) were stocked and acclimated at one ton capacity holding tanks. Fish were fed with commercial feed (4% bodyweight) for one week and starved for one-day prior to the dissection. Stomach and intestine were weighed and measured. The gastric evacuation rates were calculated using the regression model (y= ae-bx). Results of the study showed that gastric evacuation in tilapia reared in brackishwater was faster (slope= -0.7844) compared to those reared in freshwater (slope= -0.3709) as determined by the slope of the regression line. Intestinal filling time was determined by testing for the rate of food movement and intestinal passage time using One-way ANOVA at 0.05a. Intestinal passage time and rate of food movement has no significant difference in relation to salinity.