The influence of starvation on fast-start performance of Spinibarbus sinensis

Juvenile Spinibarbus sinensis (n = 48, body length, 5.86 ± 0.10 cm, 25 °C) were fasted for 0, 0.5, 1, 2, 4 and 6 weeks. The fast-start performances of the experimental fish were assessed using high-speed video photography and the locomotive kinematics analysis. The morphological parameters including tail height (H₂), tail length (L₂), lateral body area (S₁), median fin area (S₂), dorsal cross section area (S₃) and tail cross section area (S₄) were also measured using TpsDig and the Photoshop. The results showed that 6 week starvation resulted in significant decreases in the escape distance (d), maximum linear velocity (V_max) and maximum linear acceleration (a_max) of center of mass in Stage 1 and Stage 2 of fast-start process (P < 0.05), however there were two relatively sTable phases in the V_max and d, during the week 1–2 (V_max = 0.67 ± 0.06 mm/ms; d = 8.86 ± 0.73 mm) and week 4–6 (V_max = 0.31 ± 0.04 mm/ms; d = 3.70 ± 0.56 mm). When compared with the control group (0 week starvation group), only the 6 week starvation group showed the significantly different response time (t) with average t = 9.20 ± 0.37 ms in week 1–4. There were no significant difference in mass center turning angles at first stage (T_a1) , second stage (T_a2) and the sum of two stages (T_a(1+2)) was also not different (P > 0.05). The fish did not show any directional preference for left or right during escape turning, and all of the related parameters also remained unchanged among treatment group (P > 0.05). The areas of dorsal body cross-section decreased more acutely (P < 0.05) than caudal body cross-section (45.4% vs 38.0%) during the entire starvation period while no significant differences were observed in both the tail height and tail length among all treatment groups (P > 0.05). The results indicated that fast-start performance of juvenile S. sinensis is affected by the starvation; metabolic energy related traits such as the maximum linear velocity and the maximum linear acceleration decreased significantly after starvation; whereas traits with no direct link to metabolic energy such as the response time and turning angle remained unchanged during starvation. The lack of starvation induced change in the maneuverability of the fish suggests that fast-start ability related to escape strategy is relatively well conservative in juvenile S. sinensis.