Effects Of Temperature On Intestinal Microflora,immune Capacity And Oxidative Stress Of Two Wood Frog Species

As an important environmental factor,temperature can change air flow and precipitation,so as to directly or indirectly act on a wide range of animals,and have a continuous impact on individual animal health and population stability.Currently,temperature rise caused by global warming is the main threat to amphibians,but the response strategies and mechanisms of different species to temperature rise are still unclear.In this study,Rana dybowskii and Rana amurensis were studied under cold climate conditions in Northeast China to analyze the changes of intestinal flora,immune capacity and oxidative stress level of R.dybowskii and R.amurensis under different temperatures(low temperature,normal temperature and high temperature).It provides important scientific basis for breeding and protection of two species frog.The main results of this study are as follows:1.Temperature could change the species and abundance of intestinal dominant flora of both species,but did not change the overall diversity of intestinal flora.Low temperature and high temperature both reduced the abundance of Comamonas,and high temperature also increased the abundance of Pseudomonadaceae_Pseudomonas,which was different from that of R.dybowskii.The high temperatures are causing a decline in the abundance of Ruminococcus and Desulfovibrio in the intestinal flora of R.amurensis.2.High temperature can increase the percentage of lymphocyte and improve the immune ability of both species.However,compared with R.dybowskii,high temperature caused eosinophil depletion,decreased serum bactericidal ability against Aeromonas hydrophila,and Peak advance of hemagglutinin response(from 12 h to 6 h),indicating that R.amurensis was more sensitive to high temperature.3.The oxidative damage and antioxidant system damage were caused by temperature increase.CAT of both species decreased with increasing temperature,SOD activity first increased with increasing temperature,and then decreased with increasing temperature,MDA content decreased with increasing temperature at the beginning of treatment,However,with the extension of treatment time,MDA content increased with the increase of temperature,and the increase of MDA content in R.amurensis was earlier than R.dybowskii.These results indicated that the oxidative damage occurred earlier in R.amurensis than in R.dybowskii.In conclusion,temperature can have certain effects on intestinal flora,immunological parameters and oxidative stress level of R.dybowskii and R.amurensis,and R.amurensis is more susceptible to high temperature induction and response than R.dybowskii.It is speculated that this species will face more severe survival pressure under high temperature environment and be more susceptible to infection by parasites,A.hydrophila and other pathogenic bacteria.Therefore,more efforts should be made to study this species.