孵化温度对乌龟胚胎能量利用及矿物质代谢的影响

Influence of incubation temperature on embryonic use of energy and mineral metabolism in the Chinese three-keeled pond turtle Chinemys reevesii

在24℃、27℃、30℃和33℃条件下孵化乌龟(Chinemysreevesii)卵,检测温度对胚胎利用卵内能量和矿物质的影响。孵化温度显著影响乌龟胚胎的能量利用。卵在温和温度下(27℃和30℃)比在高温(33℃)和低温(24℃)孵化有较高的干物质、脂肪和能量转化率。因而,27℃和30℃新生幼体的总能量高于33℃和24℃下孵出的幼体。新生幼体内剩余卵黄随温度升高而增大。27℃下新生幼体的躯干能量显著高于其它温度。此外,孵化温度显著影响乌龟胚胎钙代谢,但对镁和钾代谢影响微弱。24℃下胚胎从卵黄和卵壳吸收的总钙量小于其它温度条件下胚胎,与之相对应,24℃下孵出卵卵壳内残留较多的钙。由此可见,温和温度(27-30℃)可提高胚胎能量转化效率,促进胚胎从卵黄和卵壳吸收较多的矿物质。

We incubated a total of 111 eggs from Chinese three-keeled pond turtle Chinernys reevesii at four constant temperatures of 24 ℃, 27℃, 30℃ and 33℃ to assess the influence of incubation temperature on embryonic use of energy and minerals. Incubation temperature significantly affected embryonic use of energy. Embryos transferred more dry matter, lipids and energy from the yolk into the hatchling when incubated at moderate temperatures （27℃, 30℃ ） than when incubated at higher （33℃） or lower temperatures （24℃）. As a result, hatchlings derived from 27℃ and 30℃ contained higher energy than did their counterparts from 33℃ and 24℃. The amount of residual yolk in hatchlings was affected by incubation temperature, with larger residual yolk at higher temperatures. The energy of the carcass was noticeably higher in hatchlings from 27℃ than from other temperatures. In addition, incubation temperature significantly affected calcium metabolism but not magnesium and kalium metabolism. Embryos incorporated a lower proportion of calcium from yolk and eggshell when incubated at 24℃ than when incubated at other temperatures. Correspondingly, more calcium remained in the shell of eggs incubated at 24℃. Therefore, in C. reevesii, moderate temperatures （27 - 30℃ ） may improve embryonic utilization of energy, promote embryonic absorption of minerals from the yolk and eggshell, and thus facilitate eggs to produce well-developed hatchlings [ Acta Zoologica Sinica 52 （1）： 21 -27, 2006].