Abstract: To explore the establishment of the immune system during postembryonic development, and provide basic biological data for further healthy culture and disease diagnosis, the changes of body mass (BM), body length (BL), the ratio of BM to BL, and the percentages of different subtypes of leukocytes from hatched group (on day 0 after hatching), sloughing group (on day 7-10 after hatching), 10-day group fed with chicken egg fluid (on day 20 after hatching), and 20day group fed with chicken egg fluid (on day 30 after hatching) were measured in the king ratsnakes (Elaphe carinata). The snakes were cultured under (26±2) ℃ indoor temperatures and 70%-80% relative humidity. Five individuals per group were sampled. BM was increased by 20.37% from day 0 to day 30, but no significant group differences were found (P>0.05). BL was longer in both sloughing and 10-day groups than that in the hatched group (P<0.05). There was no significant difference in the ratio of BM to BL among the four groups (P>0.05). No group differences were observed for the percentages of neutrophils, basophils and lymphocytes (all P>0.05). The percentage of monocytes was higher in the hatched group, and lower in the 10-day group, but did not show significant group differences (P>0.05). However, the percentage of eosinophils was significantly higher in the 10-day group than in the hatched group (P<0.05). During the 30-day postembryonic development, BM and BL displayed continuously increased tendencies, and different subtypes of leukocytes occurred before they were hatched. The percentages of monocytes and eosinophils showed reverse tendencies, the former was reduced and the latter was increased from day 0 to day 30. These results may be related to initial food stimulation after feeding and more wounded probability caused by biting each other due to their living habits, suggesting that it is necessary to feed the king ratsnakes with fluid food during early postembryonic stages, and put juvenile snakes of similar body size into the same culture room.

Key words: agricultural drought evaluation, applicability, drought index, Jilin Province