Thiamine requirement of Chinese soft‐shelled turtle, Pelodiscus sinensis (Wiegmann)

The objective of the present study was to estimate the dietary thiamine (vitamin B-1) requirement of juvenile soft-shelled turtles, Pelodiscus sinensis. Eight experimental diets containing 0, 1.90, 3.63, 5.65, 7.51, 9.62, 11.37 and 13.64 mg thiamine/kg diet were fed to 160 soft-shelled turtles reared individually for 10 weeks. The turtles had an average weight of 5.33 +/- 0.21 g. Among all the dietary groups, weight gain, feed utilization and tissue thiamine were the lowest in the turtles fed with a thiamine-free diet. The variables increased when dietary thiamine increased and then levelled off beyond 3.63 mg/kg diet. In contrast, plasma pyruvate and lactate concentrations in turtles decreased when dietary thiamine increased and then levelled off beyond 3.63 and 5.65 mg/kg diet respectively. Estimation using a broken-line regression model, the vitamin B-1 requirement of soft-shelled turtles was 3.2 mg thiamine/kg diet based on weight gain and plasma lactate concentration. When tissue thiamine and plasma pyruvate concentrations were used as the indicators, the estimated requirement was 5.4-6.5 mg/kg diet.