为优化碱解法测定中华鳖肝脏组织RNA-DNA含量比值的操作流程,选用中华鳖稚鳖的肝脏组织,在Buckley(1979)和Robbins(1990)方法的基础上,分别针对以往操作流程中匀浆介质、离心速度、碱解水浴时间和碱解量的差别进行实验.结果发现,使用由0.05 mol/L Tris-HCl+0.005 mol/L EDTA(p H7.4)组成的匀浆介质,12 000×g的离心速率,37℃碱解水浴2 h以及0.56 m L 0.3 mol/L KOH+0.25 m L 1.5 mol/L PCA的碱解酸化组合能有效提高碱解法测定中华鳖肝脏组织RNA-DNA含量比值的稳定性.
The present study was to investigate the effects of feeding time on growth of the Chinese soft-shelled turtle. The experiment was carried out with a photoperiod of 12L(light):12D(dark) with lights on at 06:00 and off at 18:00. Turtles were maintained at a temperature of 32 ± 0.2 °C in tanks throughout the length of the experiment. The turtles in group 1 to group 6 were fed respectively at 00:00, 04:00, 08:00, 12:00, 16:00 and 20:00 with 60 turtles each(Initial body weight 88.27 ± 0.09 g). Acrophases of postprandial RNA/DNA ratio in liver in each group was shown between 5h and 7h after feeding. A positive linear correlation could be seen between specific growth rate(SGR) and RNA/DNA:SGR=1.1586RNA/DNA–0.7097(r = 0.9328, P = 0.0066). The results indicated that the values at the acrophases of about 6h after feeding might be used as an instantaneous growth index in the Chinese soft-shelled turtle. The turtles in group 1 grew better than group 3, group 4, group 5, group 6, because they ate more, but they ate more and grew slower than group 2, whose feed conversion rate was also higher. Meanwhile, the SGR and feeding rate of turtles fed at 12:00 were the lowest from the six groups(P < 0.05). Turtles fed in group 1, group 2 and group 6 developed more heavy final body weight(FBW), higher feeding rate and SGR than the other three groups. This probably suggested that turtles fed in scotophase grew better than that fed at photophase in total.
An orthogonal experimental design OA_9(3~3) was used to evaluate the effects of vitamins(A, B_2, and B_6) on the growth and digestive ability of the juvenile Chinese soft-shelled turtle, Pelodiscus sinensis(initial weight, 5.9±0.2 g). A total of 135 turtles were divided into 9 groups, which each included 15 individuals. The results revealed that vitamin A(VA) had the strongest impacts on the growth rate and feed utilization among the three vitamins; 35,000 IU kg^(-1) VA had optimal effects on the feeding intake and specific growth rate, and 20,000 IU kg^(-1) VA had optimal effects on protein digestibility and the feed conversion ratio. Vitamin B_2(VB_2) was essential for regulating protein deposition and the energy efficiency for growth of the turtles; 120 mg kg^(-1) VB_2 resulted in increased protein and energy deposition, and 180 mg kg^(-1) VB_2 had greater beneficial effects on the growth rate. Vitamin B_6(VB_6) had important effects on protein and feed efficiency; however, VB_6 at an excessive level(120 mg kg^(-1)) restricted turtle growth. Based on the above growth results, dietary supplementation of VA, VB_2 and VB_6 at levels of 35,000 IU kg^(-1), 180 mg kg^(-1) and 70 mg kg^(-1), respectively, were recommended for the juvenile soft-shelled turtle.
Junwei LIZhencai YANGXiaoling HANQuansen XIEHaiyan LIU
