臺灣圈養馬來長吻鱷在非繁殖期的血液學及血漿生化學參考值之建立

Abstract

馬來長吻鱷(Tomistoma schlegelii)屬於爬蟲綱，鱷目，食魚鱷科，其形態類似恆河鱷，具有細長的口吻部，主要以魚類、水中生物為主食，但食性廣泛，主要棲息地在馬來西亞、蘇門達臘和婆羅洲的森林沼澤地，因為棲地的喪失和破碎化導致族群數量逐漸減少，甚至一度被列為瀕危物種。但因近年來國際上對馬來長吻鱷進行了保育及研究計畫，更能精確評估族群數量，而後將保育等級下修至易危物種，但仍是CITES Ⅰ的保育類動物。雖然目前國際上已有保育計畫，各國家的動物園也有些許個體期望進行繁殖，臺灣更有不少圈養個體，但目前並沒有大規模的建立關於這個物種的基本血檢值來提供臨床上個體醫療的參考依據或是幫助保育計畫的進行。因此本研究主要目的為建立馬來長吻鱷在非繁殖期的血液學及血液生化學參考值，並比較性別和年齡的影響，以期能實際運用在醫療和保育上。 實驗對象來自於私人鱷魚養殖場和動物園的29 隻母成鱷、10 隻公成鱷和16 隻一至兩歲齡的幼鱷，以物理保定從尾靜脈進行採血。血液學檢驗項目包含血容比(PCV)、血紅素(Hb)、紅白血球計數和白血球分類比例；血液生化學檢驗項目包含總蛋白(TP)、白蛋白(Albumin)、血糖(Glucose)、天冬氨酸氨基轉移酶(AST)、丙氨酸轉胺酶(ALT)、鹼性磷酸酶(ALKP)、乳酸脫氫酶(LDH)、肌酸激酶(CK)、尿素氮(BUN)、尿酸(Uric acid)、血清肌酸酐(Creatinine)、膽固醇(Cholesterol)、三酸甘油脂(Triglyceride)、血鈣(Ca)、血磷(P)、血鈉(Na)、血鉀 (K)、血氯(Cl)。另外為了得到準確的白蛋白數值，進行了血漿蛋白質電泳分析。 本實驗在非繁殖期進行，以減少繁殖生理對血檢值的影響，結果顯示性別在血容比、紅血球總數、血紅素、嗜鹼性球比例、總蛋白、白蛋白、尿酸、三酸甘油脂、血鈉、血氯、α1-球蛋白、β-球蛋白和γ-球蛋白具有顯著差異；而年齡的影響在許多項目上都有顯著差異性。比較溴甲酚綠法檢驗的白蛋白濃度和蛋白質電泳分析的白蛋白濃度，兩者結果有顯著相關，但只呈現中度相關性。因此在馬來長吻鱷的白蛋白檢驗，溴甲酚綠法無法替代蛋白質電泳法。 本研究建立了臺灣圈養馬來長吻鱷在非繁殖期的血液學和血液生化學參考值，對於未來圈養馬來長吻鱷的個體醫療和未來的相關保育工作具有重要的臨床價值。

Malaysian gharial (Tomistoma schlegelii ) belongs to Class Reptilia, Order Crocodilia and Family Gavialidae, which is a freshwater, mound-nesting crocodilian with a distinctively long, narrow snout. This species is classified as ‘Vulnerable’ in the IUCN Red List and also under CITES AppendixⅠ. They are threatened by continuing loss and fragmentation of habitat and their conservation work has got more and more attention internationally. However, there is no substantial research on reference interval of hematology and biochemistry in Malaysian gharial to assist their conservation work or evaluate individual health, the aim of this study is to establish reference interval of hematology and plasma biochemistry in Malaysian gharial under captivity in Taiwan. The subjects of this research were 29 adult females, 10 adult males and 16 yearlings from a commercial farm in Chiayi and Taipei Zoo. Blood samples were collected from ventral tail vein using needle tube of 16G or 18G intravascular catheter to avoid hemolysis or contamination of lymphoid fluid. Complete blood count and leukocyte differential count were obtained using manual method. Plasma biochemical analysis included alkaline phosphatase (ALKP), alanine aminotransferase (ALT),aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK) activities and concentrations of total protein, glucose, uric acid, urea nitrogen(BUN), creatinine, triglyceride, cholesterol, calcium and phosphate were performed using VITROS&reg; 350. Sodium, potassium and chloride were evaluated by Cobas&reg; b 121. Concentration of albumin was determined by electrophoresis. Comparisons between sexes as well as adults and yearlings were estimated using Mann- Whitney test with significance set at P<0.05. The results demonstrated that sex and age affected hematologic and biochemical values in non-breeding season. Male had significant higher value in red blood cell parameters, total protein, albumin and uric acid while female had higher triglyceride, sodium and chloride. There were many differences between adult and yearling. The result of comparing bromcresol green (BCG) dye-binding method with protein electrophoresis in determining albumin in this species indicated that albumin could not be accurately determined by BCG method and only moderate correlation between two methods. The reference interval of hematology, plasma biochemistry and protein electrophoresis in Malaysian gharial was established and could be applied to other individuals in non-breeding season. Because there were many differences between adult and yearling, it is better to establish reference interval of adult and yearling separately in next step. And considering the effect of breeding physiology, it should compare the differences between breeding and non-breeding season in the future.