| Amphibians live in complex climate condition, to adapt variable environmental conditions in different seasons, their internal organ mass and multiple immunological parameters may display some plasticity. In this paper, Bufo gargarizans, which was captured (autumn-September 17th,2012, winter-November 6th,2012, pre-hibernation-December 13th,2012, hibernation-January 17th,2013, spring-March 22th,2013, and summer-July 6th,2013) at Mengcheng countryside, Bozhou city, Anhui Province, was used to assess the sexual and seasonal differences in aspects of body mass, snout-vent length (SVL), internal organ mass, percentage of different types of leukocyte, phytohemagglutinin (PHA) response, serum bacterial killing capacity and serum cortisol concentration at whole organism, organ, tissue and hormone levels, further haematological and hormonal regulation mechanisms response to seasonal environment conditions variation were discussed, as well as possible trade-offs relationships among multiple immunological parameters were analyzed by using of morphological measurements, hematological parameters measurements, delayed-type hypersensitivity (DTH) response, serum bacterial killing assay (BKA) and serum radioimmunoassay (RIA). Main results and conclusions were as follows:1. At the whole organism level, body mass, carcass wet mass, and SVL in female toads were higher than in males. Body mass in females showed the highest in autumn, and lowest during hibernation; In males, it is the highest and lowest in summer and pre-hibernation, respectively. Water content in males and females displayed the highest in pre-hibernation and spring, respectively, and both reached the lowest in hibernation. Carcass wet mass in females was higher than in males, but not for seasonal differences; No significant sexual and seasonal differences were found for carcass dry mass. SVL in males was longer during hibernation than in autumn, and SVL in females was longer in spring than in pre-hibernation.2. At organ level, spleen wet mass in males was higher than in females. The wet mass of kidney and liver in females was heavier than in males. The wet mass of lung, heart, fat body, as well as all the organ dry mass did not show significant gender differences. The wet and dry mass of both testis and deferens did not show significant seasonal differences. Spleen wet mass in females was the highest in spring, and the lowest during hibernation and in summer. Spleen dry mass in both sexes was the highest in pre-hibernation, and the lowest during hibernation. Kidney wet mass in females was the highest in winter and spring, and the lowest in summer; It was the highest in winter, and the lowest in summer in males. Kidney dry mass in both sexes was the highest in summer, and the lowest in winter and during hibernation. Liver wet mass in females was the highest in summer and autumn, but not for males. Liver dry mass in both sexes was higher in summer than any other season. The wet mass of lung and heart was higher in autumn and spring than in summer and pre-hibernation. Lung dry mass was the highest during hibernation, and the lowest in prc-hibernation; Heart dry mass was the highest in autumn and the lowest in winter. Fat body wet mass was the highest in summer and autumn, and the lowest in spring and pre-hibernation; Its dry mass was the highest in autumn, the lowest in spring. Ovary wet mass was the highest in autumn and winter, the lowest in spring and summer. Oviduct wet mass was the highest in pre-hibernation, the lowest in spring and summer. The dry mass of ovary and oviduct in winter were higher than in spring and summer. There were no correlation relationships between spleen and ovary wet or dry mass3. No gender differences were observed in Bufo gargarizans in aspects of PHA-induced swelling responses. However, they showed significant seasonal differences, and displayed different response patterns. The peak of PHA-induced swelling responses occurred at 12 h post injection in autumn, winter, pre-hibernation and during hibernation; In spring and summer, PHA response reached the peak at 6 h, 12 h, and 24 h post injection. The maximum of PHA response was the highest in autumn, and the lowest in winter.4. At hematologic parameter level, no significant gender differences were found in percentage of various types white blood cell counts (WBCs) to total WBCs. The ratio of neutrophils to lymphocytes (N/L) in females was higher than in males. Percentage of neutrophils was the highest in autumn, and the lowest in summer. Percentage of eosinophils was the highest in summer and the lowest in autumn. Percentage of basophils was the highest during hibernation, and the lowest in spring. Percentage of monocytes was the highest during hibernation, and the lowest in winter. Percentage of lymphocytes was the highest in winter, and the lowest in summer. The ratio of N/L in both females and males was the highest in autumn, and the lowest in summer. A negative correlation was found between percentage of neutrophils and other leukocyte. Percentage of monocytes was positively correlated with that of basophils, but negatively correlated with that of lymphocytes.5. Bacterial killing capacity in males was significantly higher than in females, which showed the highest in autumn in both sexes, and the lowest in pre-hibernation in females, and during hibernation in males. No correlation relationships were found between bacterial killing capacity and N/L ratio.6. At hormone level, serum cortisol concentration in males was higher than in females. The peak of males and females was observed in winter and in pre-hibernation, respectively, both showed the lowest during hibernation. No correlation relationships were found among serum cortisol concentration and N/L ratio, and bacterial killing capacity.Under the conditions of seasonal environments, Bufo gargarizans showed gender differences and some plasticity in body mass, SVL and organ size, which may be related to changing temperature, food shortages, and seasonal reproductive status. The strength of PHA-induced swelling response, the percentage of different types of white blood cells to total WBCs, serum bacterial killing capacity, and cortisol hormone levels, all these above mentioned parameters showed different seasonal patterns, suggesting that different components of the immune system, such as cell-mediated immunity, innate immunity or acquired immunity, may be activated and utilized to cope with variable environmental conditions... |
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