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

摘要

We incubated a total of 111 eggs from Chinese three-keeled pond turtle Chinemys 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].