Distribution of tissue enzymes in three species of pinnipeds.

In domestic animal medicine, changes in serum enzyme levels are routinely used as diagnostic tools to detect liver disease. Hepatic disease occurs in pinnipeds, but limited data are available on the tissue distribution of serum enzymes in marine mammals. The objectives of this study were to determine the tissue distribution of seven serum enzymes in three pinniped species. Enzymes evaluated were alanine aminotransferase (ALT), aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), lactate dehydrogenase (LDH), creatine kinase (CK), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) in tissues from California sea lions (Zalophus californianus) (n = 5), harbor seals (Phoca vitulina) (n = 5), and northern elephant seals (Mirounga angustirostris) (n = 5) that stranded and then died at a rehabilitation center. Samples were evaluated in duplicate from liver, skeletal muscle, cardiac muscle, kidney, adrenal, spleen, pancreas, lung, lymph node, and intestine. Patterns of tissue enzyme distribution were similar in all species, with SDH activity highest in liver and kidney, CK activity highest in skeletal and cardiac muscle, ALP activity highest in adrenal, and GGT activity highest in the kidney. Aspartate aminotransferase and LDH activities were less specific, with high activity in multiple tissues. Tissue ALT activity was high in the liver of all species, but was also high in cardiac muscle (California sea lions), skeletal muscle (harbor seals), and kidney (elephant seals). These results suggest that concurrent analysis of SDH, ALT, and CK would provide high specificity and sensitivity for the detection of hepatic lesions, and allow differentiation of liver from skeletal muscle lesions in pinniped species.     

Effect of nickel deficiency on biochemical variables in serum, liver, heart and kidneys of goats.

Nickel deficiency was induced in 2- to 4-year-old goats by feeding 0.1 mg Ni/kg dry matter with a semisynthetic diet. The control group consumed 5.0 mg Ni/kg d.m. Activity of several enzymes (SDH, LDH, HBDH, AST, ALT, ALD, CK, CHE) was determined in the serum, liver, heart and kidneys. Serum urea-N level was also measured and transmission electron microscopic (TEM) examinations were performed. Signs characteristic of nickel deficiency (retarded growth, increased mortality of dam and offspring, parakeratosis of the skin) appeared in the low-nickel group. The activity of SDH and ALD, as well as the level of urea-N was significantly lower in the serum of Ni-deficient animals than in the control. Ni-deficient animals also had significantly lower enzyme activities in the heart (SDH, HBDH, AST, ALT, ALD and CK), liver (SDH and CHE) and kidneys (HBDH and CK). Electron micrographs showed degeneration of cardiac and skeletal muscle in the Ni-deficient animals. Ni deficiency elicited changes primarily in the heart and these resulted in depressed activity of several enzymes.     

The apo-enzyme content of aminotransferases in healthy and diseased domestic animals

We investigated the apo-enzyme content of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in clinically normal and ill canine, feline, equine and bovine patients. Aminotransferase activity was measured with and without the addition of exogenous pyridoxal-5'-phosphate (P5P). The amount of apo-enzyme was expressed as the percentage change in aminotransferase activity with the inclusion of P5P. The results of aminotransferase assays without P5P (holo-enzyme activity) were highly correlated to the results obtained with P5P (total enzyme activity) in all four species (Spearman rank correlations > 0.980). The median apo-aminotransferase percentage in clinically normal patients was: 11% ALT and 0% AST in 115 dogs, 7% ALT and -5% AST in 50 cats, 6% AST in 46 horses and 9% AST in 50 cattle. The amount of apo-enzyme did not increase as holo-enzyme activity increased in any of the species. The apo-aminotransferase content was not significantly different in canine, feline and equine patients with diseases affecting the liver, kidney or musculature compared to clinically normal animals. The apo-enzyme content did not differ significantly between specific liver diseases in canine and feline patients.     

Dietary fishmeal versus soyabean meal: an assessment of serum and liver enzyme response in the chicken

In a five-week feeding trial, 90 broiler chicks were used to study the response of serum and liver alanine aminotransferase (ALT) aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH) and alkaline phosphatase following the replacement of varying levels (0, 20, 40, 60, 80 and 100 per cent) of fishmeal protein by soyabean meal protein. The results showed that both serum ALT and AST activities increased significantly (P less than 0.01) with the increasing levels of substitution of soyabean meal for fishmeal. Regression analysis showed a significant (P less than 0.01) positive correlation between ALT and AST activities and the level of soyabean meal substitution with correlation coefficient, r, of 0.93 and 0.98, respectively. The liver ALT and AST tended to increase with the increasing proportion of soyabean meal although such increases were not significant (P greater than 0.01). Serum and liver SDH and alkaline phosphatase activities were not significantly influenced by diet.     

Clinical chemistry values and tissue enzyme activities in western barred bandicoots (Perameles bougainville)

BACKGROUND: The western barred bandicoot, Perameles bougainville, is an endangered Australian marsupial species whose survival is threatened by a papillomatosis and carcinomatosis syndrome. Investigations to characterize this syndrome would benefit from species-specific clinical chemistry data. OBJECTIVES: The purpose of this study was to determine plasma biochemical reference values and to determine enzyme activities in various tissues of P. bougainville. METHODS: Heparinized blood samples were collected by jugular venipuncture from 53 clinically healthy bandicoots of both sexes and at 3 geographic locations. Plasma was analyzed for routine clinical chemistry variables using an automated biochemistry analyzer. Tissues obtained following humane euthanasia of 3 bandicoots were analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK), alpha-amylase (AML), and gamma-glutamyltransferase (GGT) activities. RESULTS: Significant differences in the results were found for animals based on geographic location and sex; hence, results were expressed as minimum and maximum values. A population reference interval was calculated for AST activity (20-283 U/L). ALT was found mainly in the liver, with lower levels in cardiac and skeletal muscle and kidneys. AST was detectable in many tissues, including the heart, liver, kidneys, and central nervous system; CK was found in skeletal and cardiac muscle and central nervous system; AML was found in the pancreas; and GGT was found mainly in kidneys with lower levels in the intestines and pancreas. CONCLUSIONS: These findings will facilitate the interpretation of clinical chemistry results from P. bougainville and thereby inform population management and clinical decision-making.     

Hepatic effects of halothane, isoflurane or sevoflurane anaesthesia in dogs

The effects of halothane, isoflurane and sevoflurane anaesthesia on hepatic function and hepatocellular damage were investigated in dogs, comparing the activity of hepatic enzymes and bilirubin concentration in serum. An experimental study was designed. Twenty-one clinically normal mongrel dogs were divided into three groups and accordingly anaesthetized with halothane (n = 7), isoflurane (n = 7) and sevoflurane (n = 7). The dogs were 1-4 years old, and weighed between 13.5 and 27 kg (18.4 +/- 3.9). Xylazine HCI (1-2 mg/kg) i.m. was used as pre-anaesthetic medication. Anaesthesia was induced with propofol 2 mg/kg i.v. The trachea was intubated and anaesthesia maintained with halothane, isoflurane or sevoflurane in oxygen at concentrations of 1.35, 2 and 3%, respectively. Intermittent positive pressure ventilation (tidal volume, 15 ml/kg; respiration rate, 12-14/min) was started immediately after intubation and the anaesthesia lasted for 60 min. Venous blood samples were collected before pre-medication, 24 and 48 h, and 7 and 14 days after anaesthesia. Serum level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma-glutamyltransferase (GGT), lactate dehydrogenase (LDH GGT) activities and bilirubin concentration were measured. Serum AST, ALT and GGT activities increased after anaesthesia in all groups. In the halothane group, serum AST and ALT activities significantly increased all the time after anaesthesia compared with baseline activities. But in the isoflurane group AST and ALT activities increased only between 2 and 7 days, and in the sevoflurane group 7 days after anaesthesia. GGT activity was increased in the halothane group between 2 and 7 days, and in the isoflurane and sevoflurane groups 7 days after anaesthesia. All dogs recovered from anaesthesia without complications and none developed clinical signs of hepatic damage within 14 days. The results suggest that the use of halothane anaesthesia induces an elevation of serum activities of liver enzymes more frequently than isoflurane or sevoflurane from 2 to 14 days after anaesthesia in dogs. The effects of isoflurane or sevoflurane anaesthesia on the liver in dogs is safer than halothane anaesthesia in dogs.     

Serum liver enzyme activities in healthy Miniature Schnauzers with and without hypertriglyceridemia

OBJECTIVE: To determine whether hypertriglyceridemia in healthy Miniature Schnauzers is associated with high serum liver enzyme activities. DESIGN: Cross-sectional study. ANIMALS: 65 Miniature Schnauzers with serum triglyceride concentrations within the reference range (group 1), 20 Miniature Schnauzers with slightly high serum triglyceride concentrations (group 2), and 20 Miniature Schnauzers with moderately to severely high serum triglyceride concentrations (group 3). PROCEDURES: Questionnaires regarding each dog's medical history were completed, and serum alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and G-glutamyltransferase (GGT) activities were measured. RESULTS: Median serum ALP activity was significantly higher in group 3 than in group 1 or 2 dogs, but was not significantly higher in group 2 than in group 1 dogs. Median serum ALT activity was significantly higher in group 3 than in group 1 dogs, but was not significantly different between any of the other groups. Compared with group 1 dogs, group 2 and 3 dogs were significantly more likely to have high serum ALP activity (odds ratio, 26.2 and 192.6, respectively). Group 3 dogs also were significantly more likely to have high serum ALT activity (odds ratio, 8.0), serum AST activity (odds ratio, 3.7), and serum GGT activity (odds ratio, 11.3), compared with group 1 dogs. Group 3 dogs were significantly more likely (odds ratio, 31.0) to have > or = 2 high serum liver enzyme activities than were group 1 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that moderate to severe hypertriglyceridemia was associated with high serum liver enzyme activities in Miniature Schnauzers.     

Alanine aminotransferase apoenzyme in dogs

Unusually low serum activity of alanine aminotransferase (ALT) was detected in a Rottweiler dog with gastric dilatation-volvulus. Activity of ALT in the same sample was found to be much higher (estimated increase of 14,225%) when measured by methods adding the cofactor pyridoxal-5'-phosphate (P5P), indicating that nearly all serum ALT was in the apoenzyme form. An investigation was undertaken to determine the frequency of high serum aminotransferase apoenzyme levels in dogs. Eighty canine serum samples submitted to the Clinical Pathology Laboratory at Cornell University were assayed for ALT and aspartate aminotransferase (AST) in the presence or absence of exogenous P5P. In 79 dogs, inclusion of P5P in the LAT assay resulted in a median decrease in AST activity of -6.3% (range -33.3% to 25.0%) in all 80 dogs. One dog had an increase of 336% in ALT activity after inclusion of P5P in the assay, but lacked a similar increase in AST activity. The reason for the high levels of ALT apoenzyme in the 2 dogs was not determined.     

Plasma biochemistry of one-humped camel (Camelus dromedarius): Effects of anticoagulants and comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals but limited informations are existing for camel plasma biochemistry. Eleven clinically healthy one-humped camels were blood sampled in different tubes containing different anticoagulants and plain tubes for harvesting plasma and serum. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium, and chloride and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of AST, ALT, CK, total bilirubin, and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than in serum. Most parameters did not show any difference, but significant increase for CK activity and significant decrease for GGT, cholesterol, creatinine and chloride were seen when heparin was used as anticoagulant. Using EDTA as an anticoagulant caused a significant difference in the amounts of some measured parameters in plasma except glucose, AST, ALT, GGT, cholesterol, albumin, total protein, bilirubin, and triglyceride in comparison with serum.     

Plasma biochemistry of one-humped camel (Camelus dromedarius): effects of anticoagulants and comparison with serum

The effects of various types of anticoagulants on plasma biochemistry were studied in man and various animals but limited informations are existing for camel plasma biochemistry. Eleven clinically healthy one-humped camels were blood sampled in different tubes containing different anticoagulants and plain tubes for harvesting plasma and serum. The concentrations of glucose, cholesterol, triglyceride, total bilirubin, urea, creatinine, total protein, albumin, calcium, inorganic phosphorus, magnesium, and chloride and the activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK) and gamma glutamyl transferase (GGT) were measured. Except for the amounts of AST, ALT, CK, total bilirubin, and inorganic phosphorus, other measured parameters were significantly lower in citrated plasma than in serum. Most parameters did not show any difference, but significant increase for CK activity and significant decrease for GGT, cholesterol, creatinine and chloride were seen when heparin was used as anticoagulant. Using EDTA as an anticoagulant caused a significant difference in the amounts of some measured parameters in plasma except glucose, AST, ALT, GGT, cholesterol, albumin, total protein, bilirubin, and triglyceride in comparison with serum.     

Plasma and tissue enzyme activities in the cat

The levels of activity of sorbitol dehydrogenase (SDH), alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) and its isoenzymes, α-hydroxybutyric dehydrogenase (α-HBDH) and creatine kinase (CK) were determined in various tissues of six clinically normal cats. The plasma half times (T_1/2) of several hepatic enzymes were also measured in three clinically normal cats.     

Experimental paratuberculosis (Johne's disease)--studies on biochemical parameters in cattle

Ten male Holstein-Friesian calves naturally infected by Mycobacterium paratuberculosis were experimentally re-infected orally at an average of 17 days. Monthly measurements were conduced of the following activities, in the period between post infection days 160 and 400: total protein (TPR), albumin (ALB), cholesterol (CHOL), triglycerides (TRIG), Zn and Cu concentrations as well as sorbitol dehydrogenase, lactate dehydrogenase (LDH), alpha-hydroxybutyrate dehydrogenase (alpha-HBDH), gamma-glutamyltransferase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), alkaline phosphatase and fructose-1,6-diphosphate aldolase (ALD). TPR, ALB, TRIG, and CHOL were reduced by day 400, in conjunction with disorders of digestion and absorption. Increased activities of CK, ALD, LDH, alpha-HBDH, AST and ALT primarily indicated damage to skeletal muscle and/or liver. Serum CK and ALD activities as well as TRIG and TPR concentrations may serve as aids to specific diagnosis of paratuberculosis, particularly in the advanced stage of the disease.     

Serum enzyme changes in lambs with experimentally induced acute muscular dystrophy

An experiment was performed to study some serum enzyme changes taking place in artificially fed lambs made dystrophic on a skim milk ration supplemented with α-tocopherolextracted cod liver oil. In the course of two to three weeks the lambs showed highly increased serum values of aspartate- and alanine aminotransferase (AspAT = GOT and A1AT = GPT), total lactate dehydrogenase (LDH), and creatine phosphokinase (GPK). The latter enzyme proved to be the most sensitive test of myopathies, with serum values above 1000 times the normal level. A high-grade hyaline skeletal muscle degeneration was confirmed by histology. Myocardial changes were also present.Contrary to expectations, electrophoretic separation of LDH isoenzymes in the serum of the dystrophic lambs did not reflect any increase of the prevalent muscular cathodic thermolabile fraction LDH₅. The use of a so-called LDH heat stability test as an aid in clinical diagnostic work, as previously suggested, therefore does not seem to be valid in this disease. The results are discussed.     

Serum enzyme activity evaluated in budgerigars (Melopsittacus undulatus) inflicted with muscle injury

Aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations were measured in 73 budgerigars. In spite of increases in the serum concentration of AST and ALT the loss of enzyme activity from the injection site occurred at about the same rate for all four enzymes tested. The rate constants, calculated in birds administered muscle extract via the intravenous or the intramuscular route of injection, disclosed that in subjects treated intramuscularly the serum enzyme elevation was dependent on the elimination half-life of the enzyme and partly on the rate at which the particular enzyme was absorbed into the bloods-tream. Moreover, serum enzyme elevations correlated inversely with total clearance. To determine the aetiology of blood enzyme elevation in budgerigars, for diagnostic purposes, the absorption rate, total clearance and elimination half-life of each of these four enzymes are deemed valuable components.     

Toxicity of dietary monensin in quail

Quail were fed monensin to determine liver damage, as measured by changes in activities of serum enzymes and liver microsomal enzymes. Monensin fed at a therapeutic level of 110 ppm for 2 weeks produced an increase in cytochrome P-450 and cytochrome b5 and induction of the activities of benzphetamine N-demethylase, aminopyrine N-demethylase, and aniline hydroxylase, with no changes in the activities of serum sorbitol dehydrogenase (SDH), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). On the other hand, quail fed 110 ppm, 220 ppm, and 330 ppm monensin in feed for 6 weeks showed a significant rise in SDH and AST activities at 330 ppm but not at 110 ppm and 220 ppm. The manifestations of liver toxicity observed at 330 ppm were accompanied by a significant decrease in all the aforementioned hepatic microsomal mixed-function oxidases. In contrast, quail fed monensin at 110 ppm and 220 ppm for 6 weeks produced no change in these parameters except for benzphetamine N-demethylase, aminopyrine N-demethylase, and aniline hydroxylase, which were significantly increased in birds fed 220 ppm of monensin.     

Clinicopathologic evaluation of hepatic lipidosis in periparturient dairy cattle

BACKGROUND: Fatty change of the liver (FCL) is very common in dairy cattle periparturiently. Many laboratory methods have been implicated in order to assist the diagnosis. HYPOTHESIS: To investigate whether FCL in dairy cattle could be evaluated by assessment of ornithine carbamoyl transferase (OCT) by means of an assay modified for bovine serum, other enzyme activity, serum bile acids (SBA) concentration, or other biochemical constituents. ANIMALS: A total of 187 dairy cattle were included: 106 were suspected to have liver dysfunction and were examined after referral by veterinarians; 70 were clinically healthy with mild FCL; and 11 were clinically healthy without FCL. METHODS: Blood and liver biopsy samples were obtained after clinical examination. Histologic examination by light microscopy and classification of samples according to the severity of FCL was done, and total lipid and triglyceride concentration was measured. In serum, OCT, aspartate aminotransferase (AST), alanine aminotransferase (ALT), sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GDH), alkaline phosphatase (ALP), and gamma-glutamyltransferase (gamma-GT) activity as well as SBA, glucose, ketones, total bilirubin (tBIL), and nonesterified fatty acids (NEFA) concentration were measured. RESULTS: OCT and AST activity and tBIL concentration correlate well with the degree of FCL. SBA concentration does not contribute well to FCL diagnosis. The majority of FCL cases appeared within the first 21 days-in-milk (DIM). The majority of moderate-to-severe and severe FCL cases arose in the first 7 DIM. CONCLUSIONS AND CLINICAL IMPORTANCE: Except for OCT, AST, and tBIL, none of the biochemical tests used, including SBA, had sufficient discriminatory power to differentiate reliably between mild and severe FCL because of poor sensitivity. A weak correlation between clinical signs and the extent of FCL was evident.     

高温应激致麒麟鸡(卷羽鸡)肝损伤试验动物模型的建立

本试验旨在建立急性应激致禽类肝损伤的试验动物模型.对麒麟鸡(卷羽鸡)进行持续高温应激后,检测血清中的肝损伤酶谷丙转氨酶(ALT)、天冬氨酸转氨酶(AST)、胆碱脂酶(CHE)和乳酸脱氢酶(LDH)活性的改变,观察肝脏病理组织学变化.结果显示,高温应激前期,麒麟鸡血清肝损伤酶AST和ALT活性极显著升高(P <0.01),高温应激后期,AST活性显著低于正常水平(P <0.05),而ALT活性极显著低于正常水平(P <0.01);持续高温应激期间,CHE的活性一直低于正常水平,高温应激后期,CHE活性极显著低于正常水平(P <0.01);在高温应激下LDH活性呈先下降后上升再下降的变化趋势,高温应激后期,LDH活性极显著高于正常水平(P <0.01).高温应激引起麒麟鸡肝细胞出现水泡变性、肝细胞核浓缩现象.结果表明,采用急性热应激可诱导麒麟鸡肝损伤试验模型,试验模型具备肝脏水泡变性和核浓缩病理特征.     

Liver histopathology and liver and serum alanine aminotransferase and alkaline phosphatase activities in epileptic dogs receiving phenobarbital

Phenobarbital (PB) therapy is frequently associated with elevated serum alanine aminotransferase (ALT) and alkaline phosphatase (AP) activities in dogs without clinical signs of liver disease. The goal of this study was to determine if increased serum ALT and AP activities in clinically healthy PB-treated epileptic dogs are due to hepatic enzyme induction or to subclinical liver injury. Liver biopsies were obtained from 12 PB-treated dogs without clinical signs of liver disease but with elevated serum ALT and/or AP activities or both. Liver biopsies were obtained from eight healthy control dogs not receiving PB. Biopsies were evaluated histopathologically (all dogs) and liver homogenates were assayed for ALT (all dogs) and AP (six treated dogs, all controls) activities. As a positive control, liver cytochrome P4502B, an enzyme known to be induced by PB, was measured by benzyloxyresorufin-O-dealkylase activity and immunoblotting (five treated dogs, all controls). Serum AP isoenzyme analyses were performed. Results showed that ALT and AP activities in liver homogenates were not increased in treated dogs compared with controls, whereas the positive control for induction, CYP2B, was dramatically increased in treated dogs. Histopathological examination of liver biopsies revealed more severe and frequent abnormalities in treated dogs compared to controls, but similar types of abnormalities were found in both groups. Serum AP isoenzyme analyses in treated dogs demonstrated increased corticosteroid-induced and liver isoenzyme activities compared to controls. Results do not support induction of ALT or AP in the liver as the cause of elevated serum activities of these enzymes due to PB.     

Effects of long-term phenobarbital treatment on the liver in dogs

Long-term administration of phenobarbital has been reported to cause hepatic injury in dogs. Phenobarbital induces hepatic enzymes, and it may be difficult to distinguish the effect of enzyme induction on serum liver enzyme activities from actual hepatic damage. The hepatotoxicity of phenobarbital and the impact of enzyme induction on serum liver enzyme activity were investigated prospectively in 12 normal dogs. Phenobarbital was administered for 29 weeks at 5 mg per kilogram of body weight (range, 4.8— 6.6 mg/kg) PO q12h, resulting in therapeutic serum phenobarbital concentrations (20–40 μg/mL). Serum alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), γ-glutamyltransferase (GGT), fasted bile acids (fBA), total bilirubin, and albumin were determined before and during treatment. Lateral abdominal radiographs, abdominal ultrasounds, and histopathologic examinations of liver tissue obtained by ultrasound-guided biopsy were performed before and during treatment. Radiographs revealed a moderate increase in liver size in most dogs. Ultrasonographic examination revealed no change in liver echogenicity or architecture. No evidence of morphologic liver damage was observed histopathologically. ALP and ALT increased significantly ( P < .05), GGT increased transiently, and albumin decreased transiently during the study. There were no significant changes in AST, bilirubin, and fBA. These results suggest that increases in serum ALP, ALT, and GGT may reflect enzyme induction rather than hepatic injury during phenobarbital treatment in dogs. Serum AST, fBA, and bilirubin, and ultrasonographic evaluation of the liver are not affected by the enzyme-inducing effect of phenobarbital and can therefore be helpful to assess liver disease in dogs treated with the drug.     

Hepatic effects of halothane and isoflurane anesthesia in goats

OBJECTIVE: To determine hepatic effects of halothane and isoflurane anesthesia in young healthy goats. DESIGN: Randomized prospective clinical trial. ANIMALS: 24 healthy 9-month-old female goats. PROCEDURE: Goats were sedated with xylazine hydrochloride and ketamine hydrochloride and anesthetized with halothane (n = 12) or isoflurane (12) while undergoing tendon surgery. End-tidal halothane and isoflurane concentrations were maintained at 0.9 and 1.2 times the minimal alveolar concentrations, respectively, and ventilation was controlled. Venous blood samples were collected approximately 15 minutes after xylazine was administered and 24 and 48 hours after anesthesia, and serum aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), alkaline phosphatase (ALP), and gamma-glutamyltransferase (GGT) activities and bilirubin concentration were measured. Goats were euthanatized 25 or 62 days after anesthesia, and postmortem liver specimens were submitted for histologic examination. RESULTS: All goats recovered from anesthesia and survived until euthanasia. Serum SDH, GGT, and ALP activities and bilirubin concentration did not increase after anesthesia, but serum AST activity was significantly increased. However, serum hepatic enzyme activities were within reference limits at all times in all except 1 goat in which serum AST activity was high 24 and 48 hours after anesthesia. This goat had been anesthetized with halothane and had the longest duration of anesthesia. No clinically important abnormalities were seen on histologic examination of liver specimens. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of halothane or isoflurane for anesthesia in young healthy goats is unlikely to cause hepatic injury.