| Chinese sturgeon,Acipenser sinensis,is a large anadromous species,and it is listed as first-class protected wild animals by the Chinese government.In the late 20th century,due to habitat lose,overfishing and pollution,the population of Chinese sturgeon has been degraded.The Yangtze estuary is an important habitat and migration rought for both young and adult Chinese sturgeon.However,Chinese sturgeon caught by mistake,injured by shipping and stranded on shore,happened frequently.It is necessary to carry out rescue research of Chinese sturgeon in the Yangtze estuary.The blood physiological and behavioral characteristics are important indicators in the rescue diagnosis of Chinese sturgeons.What are the suitable methods to carry out research on the blood physiology and behavior characteristics of Chinese sturgeon?What are the effects of commonly used research methods on the physiology and behavior characteristics?What is the relationship between the blood physiological and behavioral characteristics and the changes in gender,season,nutrition,and age?How to determine the normal physiological and behavioral characteristics of Chinese sturgeon and its application in rescue work?In this study,the physiological and behavioral characteristics of Chinese sturgeon,Acipenser sinensis,cultured in artificial condition were investigated,and the implications of the results in the conservation of Chinese sturgeon were discussed.1.The physiology and behavior research methods of Chinese sturgeon under artificial conditions were improved.Firstly,the timing effect of cryopreservation of blood on the Chinese sturgeon blood physiological and biochemical indicators was explored.The results showed that there was no significant impact on the blood samples within 1 day of freezing and thawing process.While the total protein（TP）,globulin（GLO）,urea（UREA）,and high-density cholesterol（HDL-CHOL）showed significant differences after one-week ultra-low temperature freezing.We recommend that the blood samples should be avoided re-freezing and re-thawing,and the sample will be tested within one week if re-freezing and re-thawing process cannot be avoided.The effects of centrifugation temperature（4℃,25℃）and rotation speed（4000 r/min,10000 r/min）on blood biochemical indexes of Chinese sturgeon were studied.The results showed that centrifugation temperature had an effect on UARE and K+,while rotation speed had no effect on biochemical indexes.Thus,low speed centrifugation（4000 r/min）at constant temperature（4℃）is recommended for sample preparation.The effects of anticoagulants（heparin,EDTA-2K）on blood biochemical indexes were studied.The results showed that EDTA-2K anticoagulants had a significant effect on alanine aminotransferase（ALT）,aspartate aminotransferase（AST）,lactate dehydrogenase（LDH）,total protein（TP）,albumin（ALB）,total bilirubin（TBIL）,glucose（GLU）,UREA,triglycerides（TG）,triglyceride（TG）,high density lipoprotein（HDL）,low density lipoprotein（LDL）,Uric acid（UARE）,total cholesterol（CHOL）,alkaline phosphatase（ALP）,total bile acid（TBC）and amylase（AMY）（P<0.05）,while no obvious effect on heparin anticoagulant.We recommended that serum samples were the main roles in the detection of blood biochemicals and heparin can be used in plasma preparation for rapid detection.The effects of microscopic visual classification counting and automatic blood cell analyzer classification counting on blood cell analysis of Chinese sturgeon were compared and analyzed.The results showed that the automatic blood cell analyzer is not suitable for the detection of Chinese sturgeon blood cells because the morphological and structural characteristics of Chinese sturgeon blood cells are quite different from those of mammals.Therefore,under current conditions,the analysis of blood cell count of Chinese sturgeon still needs to use the traditional microscope visual counting method.A method for observing the behavior and growth of Chinese sturgeon under artificial conditions has been established by continuously observing the behavior and growth of two adult Chinese sturgeon under artificial conditions for one year.The results showed that the swimming,breathing,and feeding behavior of adult Chinese sturgeon had similar seasonal characteristics.The male was more sensitive to seasonal changes than the female.This sensitivity is mainly reflected in the differences in feeding behavior and growth.The results indicated that suitable breeding environment should be provided to promote feeding activities in the cultivation process of adult Chinese sturgeons to improve the growth effect.The established behavior and growth observation methods have application value in the study of Chinese sturgeons.2.Physiological and behavioral characteristics of Chinese sturgeon under artificial conditions were investigated.Conducted a study on gender differences in blood physiology and behavior characteristics of Chinese sturgeon.The results showed that female and male Chinese sturgeon blood biochemical indicators of LDL,TG,Ca2+were significantly different（P<0.05）,LDH,HDL,K+,estradiol（E2）,testosterone（T）,11-ketotestosterone（11-KT）were extremely significant different（P<0.01）,and there is no significant difference in blood cell indicators（P>0.05）between female and male.The proportion and frequency of food intake are not significantly different（P>0.05）.LDH,HDL,LDL,E2,K+of females are significantly higher than males,and TG,Ca2+,T,11-KT of males were significantly higher than females.The results revealed that there are gender differences in blood biochemical indicators of Chinese sturgeon,which is related to the physiological heterogeneity of different sexes of Chinese sturgeon.In addition to sex steroid hormones,blood biochemical indexes have potential application value in sex determination of Chinese sturgeons,which is worthy of further study.The seasonal differences of blood physiological and behavioral characteristics of Chinese sturgeon were studied.The results showed that Chinese sturgeon prefers to eat fresh feed,and the seasonal difference in feeding behavior was significant（P<0.05）,which is associated with water temperature change（P<0.05）.Seasonal changes resulted in shorter annual suitable growth period and lower intake of bait,and the growth of Chinese sturgeons was slow throughout the year.Using indirect growth indicators to analyze the seasonal differences in growth,there is a very significant seasonal difference（P<0.01）,indicating that the growth characteristics of Chinese sturgeons could be better reflected through the analysis of indirect growth indexes.The seasonal difference of blood cell indexes was significant（P<0.05）,except for CK,CHOL,HDL,the seasonal difference of blood biochemical indexes was not significant（P>0.05）,and the other indexes were significantly different（P<0.05）.The results showed that Chinese sturgeon’s behavior had typical seasonal differences,and different physiological indicators had different seasonal differences.The seasonal differences in physiology and behavior are mainly related to changes in water temperature rhythm.Therefore,in the cultivation and management of Chinese sturgeon,strengthening the regulation of water temperature,providing suitable conditions,and improving the feeding and growth effect should be paid attention to.The effects of diet type on blood physiology and growth of Chinese sturgeon were studied.The results showed that different diet types had significant effects on the physiology and growth of Chinese sturgeon.The contents of K,11-KT,TP,ALB,and GLO in the fresh diet group were significantly higher than those in the compound feed group（P<0.05）,indicating that the fresh feed could promote the development of gonad and immunity of fish,and the growth index is significantly higher than that of the compound feed group（P<0.05）.The results revealed that although Chinese sturgeon can adapt to long-term ingestion of compound diet,its growth performance and health are not as good as eating fresh feed.This difference was related to the nutritional requirements of species and nutrient composition of feed.The nutritional requirements of Chinese sturgeon should be studied in detail to provide technical support for the development of high-quality compound feed in line with the growth and development needs of Chinese sturgeon.The age difference of blood physiological characteristics of Chinese sturgeon showed that there were significant differences in blood physiological indexes of Chinese sturgeon with age increase,and different indexes showed different change rules.ALT,AST,ALP,CREA,UREA,GLU showed a downward trend,LDH,CK,TP,ALB,GLO,CHOL,p H,RBC,E2,T,11-KT showed a rising trend,TG,HDL,LDL,CRP first declined and then rised.Although there are inter-annual differences in the other indicators,the overall changes are relatively stable.This change is mainly affected by differences in growth and development and metabolism levels that occur with age.3.The application research of physiological and behavioral characteristics in rescue of Chinese sturgeon under artificial conditions was carried out.Firstly,the Chinese sturgeon blood physiological and behavioral characteristic index reference values were established,using statistical methods,based on large sample data,including 34 blood biochemical index reference values,8 blood cell index reference values,and 7 behavior and growth index reference values.Secondly,using the established Chinese sturgeon physiological and behavioral inspection methods,based on the blood physiological indicators to identify and diagnose the health status of the diseased Chinese sturgeon,it was found that the blood biochemical indexes could well reflect the impaired hepatic and renal gill function of Chinese sturgeons suffering from mad swimming disease.The blood biochemical indexes could well reflect the abnormal hepatobiliary function of Chinese sturgeon with hepatobiliary disease,and there were abnormal changes in renal gills,nutrient metabolism and electrolyte balance.The results showed that blood biochemical indexes could effectively reflect the physiological changes of diseased fish,indicating that blood biochemical indexes had application value in health diagnosis of Chinese sturgeon.Thirdly,based on the blood physiological indicators to study the rescue technology of injured Chinese sturgeon,we studied the physiological and behavioral characteristics of an injured adult Chinese sturgeon（No.717）during the rescue.Results showed that the injured Chinese sturgeon mainly has external injuries,body stress symptoms,and unstable behavior in early rescue.Respiratory rate（42.0±6.7 times/min）,tail swing rate（22.5±2.7 times/min）,and swimming speed（0.65±0.13m/s）.Insufficient nutrient supply leaded to a decrease in glycoprotein and lipid metabolism（TP is 27 g/L,ALB is 10 g/L,GLO is 17 g/L,GLU is 2.3 mmol/L,CHOL is 0.8 mmol/L）.Therefore,the injured Chinese sturgeon was taken rescue measures such as water temperature control,salinity regulation and nutrition supply,etc.After more than 5 months of rescue,the injured Chinese sturgeon has basically recovered from the trauma,breathing rate（39.1±2.8 times/min）,tail swing frequency（29.6±2.5 times/min）,swimming speed（0.55±0.09m/s）,and other behavioral indicators tend to stabilize,and blood biochemical indicators are restored（TP is 55 g/L,ALB is 24.8 g/L,GLO is 30.2 g/L,GLU is 3.67mmol/L,CHOL is 2.3 mmol/L）,indicating that physiological and behavioral indicators can provide a scientific reference for the rescue work of injured Chinese sturgeon.Fourthly,the established reference values of physiological and behavioral indicators were used to evaluate the blood physiological indicators of diseased and injured abnormal development and healthy Chinese sturgeons,which verified that the established reference values had relatively reliable applicability and practical application value.4.The methods established in this research still need to be tested in long-term practical applications in the future.At the same time,with the emergence of new research techniques and methods,the physiology and behavior research methods of Chinese sturgeon also need to be continuously improved and perfected in practice.Chinese sturgeon has a long life cycle,and the age range of Chinese sturgeon in this study is limited,so it is necessary to continue sample collection on the basis of this study in the future,especially the supplement of samples from sexually mature groups,which will help improve the reference value of indicators and provide support for establishing the indicator system of physiological and behavioral characteristics of Chinese sturgeons in the whole life cycle.In this study,it was found that fresh bait had a good improvement effect on blood physiology and growth characteristics of Chinese sturgeon,and its mechanism deserve further study. |
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