THE EFFECTS OF AEROBIC EXERCISE ON GUT EVACUATION OF JUVENILE QINGBO (SPINIBARBUS SINENSIS) AND THE ASSOCIATED MATHEMATICAL MODELS

Here we investigated the effects of aerobic exercise on gut evacuation and the associated mathematical models of juvenile qingbo (Spinibarbus sinensis). One hundred and eight fish (24.470.03) g, (10.900.02) cmwere subjected to aerobic exercise at water velocities of control (3cm/s, CG), 1 body length/s (1BL/s, 1TG), and 2 BL/s (2TG) at (250.5)℃ for 8 weeks. All fish from the control group (CG) and exercise groups (1TG and 2TG) were lightly anaesthetized and compulsively fed with compound diet (1.45% of the body weight). Then we collected and analyzed the wet mass of intestinal content at different time. The percentages (dry mass of residual diet/dry mass of total diet) of the residual diet in the intestine were also calculated and fitted with three common mathematical equations (linear, exponential and square-root). The results indicated that the aerobic exercise training induced a significant increase in the weight specific growth rate (WSGR) compared to CG (P0.05). In both CG and the training groups, the dry mass of the intestinal content and the percentages of the residual diet decreased significantly over time after feeding. We determined that the square-root model best described the gut evacuation among all three mathematical models. The intestinal evacuation rate of CG (0.41%/h) was much lower than that of 1TG and 2TG (both 0.48%/h), and the intestinal evacuation time of the 1TG (20.39h) and 2TG (20.33h) was much shorter than that of the CG (24.51h). These results suggested that aerobic exercise could not change the intestinal evacuation and the associated mathematical model, but might significantly increase the intestinal evacuation rate and shorten the evacuation time.