[The lipidosis in the liver of the dairy cow: Part 2 Genetic predisposition and prophylaxis]

Hepatic lipidosis in dairy cows is the result of a disturbed balance between the uptake of non-esterified fatty acids (NEFA), their metabolism in the hepatocytes, and the limited efflux of TG as very-low-density lipoprotein (VLDL). Lipidosis and the associated risk for ketosis represents a consequence of selecting dairy cows primarily for milk production without considering the basic physiological mechanisms of this trait. The overall risk for lipidosis and ketosis possesses a genetic background and the recently released new breeding value of the German Holstein Friesian cows now sets the path for correction of this risk and in that confirms the assumed genetic threat. Ectopic fat deposition in the liver is the result of various steps including lipolysis, uptake of fat by the liver cell, its metabolism, and finally release as very-low-density lipoprotein (VLDL). These reactions may be modulated directly or indirectly and hence, serve as basis for prophylactic measures. The pertaining methods are described in order to support an improved understanding of the pathogenesis of lipidosis and ketosis. They consist of feeding a glucogenic diet, restricted feeding during the close-up time as well as supplementation with choline, niacin, carnitine, or the reduction of milking frequency. Prophylactic measures for the prevention of ketosis are also included in this discussion.

Ocular Surface Biology and Disease in Amphibians

Vision is essential for amphibians, so a healthy ocular surface is critically important. There are ocular surface abnormalities that occur predominantly in captive animals, such as corneal lipidosis, whereas others, such as UV-induced trauma or infectious and parasitic conditions, may be critical to survival for animals in the wild. It is believed that inherited defects are going to be seen in small captive populations but it may be that confined wild groups of amphibians can be just as severely affected. Anything that blinds an animal severely affects its life changes.

Splenic lipidosis in intensively cultured perch, Perca fluviatilis L

Macroscopically visible lipid deposition varying in size from pinpoint to 8-mm diameter was found in spleens of a population of intensively farmed perch, Perca fluviatilis L. over a 24-month rearing period. Large agglomerates of adipocytes distinguishable from surrounding normal tissue occurred in all individuals with spleen lipidosis. Several affected fish presented total dystrophy of large clusters of hepatocytes. Prevalence of lipidosis was 5.0% at 12 months and 16.6% at 24 months. There was no significant difference between fatty acid profiles of liver or perivisceral fat of perch with and without lipidosis except for linoleic, myristic, γ-linoleic, cis-eicosatrienic, palmitooleic acid. Body weight and hepatosomatic, perivisceral fat and splenosomatic indices were not associated with lipidosis. There was no significant effect of lipidosis on mortality or growth.

Hepatic Lipidosis in a Research Colony of Big Brown Bats (Eptesicus fuscus)

During a nearby construction project, a sudden decrease in food intake and guano production occurred in an outdoor colony of big brown bats (Eptesicus fuscus), and one animal was found dead. Investigation revealed that the project was generating a large amount of noise and vibration, which disturbed the bats' feeding. Consequently the bats were moved into an indoor enclosure away from the construction noises, and the colony resumed eating. Over the next 3 wk, additional animals presented with clinical signs of lethargy, weight loss, ecchymoses, and icterus and were necropsied. Gross necropsy of the affected bats revealed large, pale yellow to tan, friable livers with rounded edges that floated when placed in 10% neutral-buffered formalin. Some bats had ecchymoses on the webbing and skin and gross perirenal hemorrhage. Histologic examination showed hepatic and renal tubular lipidosis. The clinical and pathologic signs of hemorrhage and icterus were suggestive of hepatic failure. Hepatic lipidosis was attributed to stress and inappetence associated with environmental perturbations. Once the environmental stressor was removed, the colony morbidity and mortality decreased. However, 2 y later, a series of new environmental stressors triggered additional deaths associated with hepatic lipidosis. Over a 9-y period, 21 cases of hepatic lipidosis were diagnosed in this bat colony.

Changes of very low-density lipoprotein concentration in hepatic blood from cows with fasting-induced hepatic lipidosis

The purpose of this study was to evaluate changes of very low-density lipoprotein (VLDL) components in hepatic blood (HB) from 5 nonlactating nonpregnant cows fasted from days 0 to 3 and subsequently refed to day 10 and, in addition, to assess those of other lipoproteins. Increased phospholipid concentrations in each lipoprotein after the start of fasting suggested their availability for the surface lipids of lipoproteins. Although the VLDL-triglyceride (TG) concentration in HB from all cows increased on day 1, the value on day 4 became similar to that on day 0. However, the concentration on day 10 was significantly increased. In all cows, the decreased ratio of the VLDL-TG concentration in HB to the non-esterified fatty acids (NEFA) concentration in portal blood (PB) on day 4 appeared to reflect relatively decreased secretion of TG as VLDL by NEFA excessively mobilized to the liver via PB. The markedly increased ratio on day 10 was considered to contribute to the improvement of hepatic lipidosis.

Gallbladder mucocoele and concurrent hepatic lipidosis in a cat

A 3-year-old Domestic Shorthair cat was presented with weight loss, anorexia and icterus. Feline hepatic lipidosis and gallbladder mucocoele were diagnosed; this is the first report of gallbladder mucocoele in the cat. The case was managed successfully with cholecystojejunostomy, gastrostomy tube placement and tube feeding for 3 months. The cat has survived over the long term with minimal complications.

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.

Cytologic diagnosis of diseases of hedgehogs

This article focuses on neoplastic diseases because they may be the most frequent disease processes in captive hedgehogs according to the literature and authors' case files and the most common cases submitted for cytologic diagnosis in these species, particularly the African hedgehog (Atelerix albiventris).

Hepatic lipidosis in a black-headed python (Aspidites melanocephalus)

The number of people keeping reptiles in captivity has markedly increased, and widespread inappropriate husbandry will result in an increasing incidence of the diagnosis of hepatic lipidosis(HL). It may become apparent that some species of snake have predisposition to develop HL. In the specific instance of the genus Aspidites, alterations to the usual husbandry that limit feeding and thereby body weight should markedly lessen the chance of the animal's developing HL. It is important for clinicians to develop a more aggressive approach to these cases and to build a bank of data with which to promote understanding of this common malady.

Spontaneous, generalized lipidosis in captive greater horseshoe bats (Rhinolophus ferrumequinum)

During a routine 6-month quarantine period, 3 of 34 greater horseshoe bats (Rhinolophus ferrumequinum) captured in mainland China and transported to the United States for use in echolocation studies were found dead with no prior history of illness. All animals were in good body condition at the time of death. At necropsy, a large amount of white fat was found within the subcutis, especially in the sacrolumbar region. The liver, kidneys, and heart were diffusely tan in color. Microscopic examination revealed that hepatocytes throughout the liver were filled with lipid, and in some areas, lipid granulomas were present. renal lesions included moderate amounts of lipid in the cortical tubular epithelium and large amounts of protein and lipid within Bowman's capsules in the glomeruli. In addition, one bat had large lipid vacuoles diffusely distributed throughout the myocardium. The exact pathologic mechanism inducing the hepatic, renal, and cardiac lipidosis is unknown. The horseshoe bats were captured during hibernation and immediately transported to the United States. It is possible that the large amount of fat stored coupled with changes in photoperiod, lack of exercise, and/or the stress of captivity might have contributed to altering the normal metabolic processes, leading to anorexia and consequently lipidosis in these animals.

Clinical Application of Computed Tomography for the Diagnosis of Feline Hepatic Lipidosis

The usefulness of computed tomography (CT) for the diagnosis of feline hepatic lipidosis (FHL) was evaluated. Liver CT number was 54.7+/-5.6 HU (mean+/-SD) in 26 healthy cats. We fast 6 healthy cats for 72 hr to induced FHL experimentally and the cats were assessed by CT and serum biochemical analysis. Liver CT number of the six cats was 53.8+/-3.0 HU before fasting, 46.8+/-2.4 HU after fasting, and 50.2+/-3.6 HU two weeks after restarted feeding. The decreased CT number was associated with the elevation of serum non-esterified fatty acid (NEFA) and beta-hydroxybutyrate levels. These results indicate that measurement of CT number of the liver is an effective procedure for the diagnosis of FHL.

Caprine hepatic lipidosis induced through the intake of low levels of dietary cobalt

Forty-one, 10-week-old newly weaned goats were randomly allocated into two groups, namely control (n=22) and treated (n=19). Kids in both groups were fed Rhodegrass hay ad libitum that contained < 0.1 mg/kg DM cobalt and 150 g/day of a commercially prepared ruminant concentrate that contained approximately 0.12 mg/kg DM cobalt. This diet provided the minimum daily requirement of cobalt as specified for sheep. The treated goats were supplemented with bi-monthly subcutaneous injections of 2000 microg of hydroxycobalamin. All goats were weighed and blood samples collected monthly for haematological, clinical biochemical and serum vitamin B12 analysis. After a 10-month experimental period the goats were slaughtered. The control animals exhibited significantly (P<0.05) lower weight gains, and had dry scruffy hair coats. In addition, there was a decline in erythrocyte counts, mean haemoglobin, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. Controls also exhibited significantly (P<0.05) lower levels of total serum proteins and elevated levels of serum alkaline phosphatase compared to treated goats. Fourteen (63.6%) of the control goats developed pathology consistent with reported field cases of hepatic lipidosis associated with low liver levels of cobalt. Only one (5.3%) of the treated goats developed hepatic lipidosis. Contrary to previous reports that suggested that goats are less sensitive to low levels of dietary cobalt than sheep, it is apparent that this is not the case with Omani goats. This is the first report of the induction of hepatic lipidosis in goats due to feeding low levels of cobalt in their diet.

Hepatic lesions in cetaceans stranded in the Canary Islands

This article describes the gross, histopathologic, and ultrastructural findings of the livers of cetaceans stranded on the coast of the Canary Islands between 1992 and 2000. A total of 135 cetaceans were included in the study, among which 25 were common dolphins (Delphinus delphis), 23 Atlantic spotted dolphins (Stenella frontalis), 19 striped dolphins (Stenella coeruleoalba), and 15 other species of dolphins and whales. The most common lesion observed in these animals was a nonspecific chronic reactive hepatitis (47/135), followed by hyaline intracytoplasmic inclusions in hepatocytes (33/135). Parasitic cholangitis was detected in 8/135 animals, whereas hepatic lipidosis was presented in 7/135 animals. The ultrastructure of hyaline hepatocytic cytoplasmic inclusions is described, and possible causes of these inclusions are discussed.

Plasma lipids, lipoprotein composition and profile during induction and treatment of hepatic lipidosis in cats and the metabolic effect of one daily meal in healthy cats

Anorexia in obese cats may result in feline hepatic lipidosis (FHL). This study was designed to determine plasma lipids and lipoprotein profiles in queens at different stages during experimental induction of FHL (lean, obese, FHL), and after 10 weeks of treatment. Results were compared with those obtained from lean queens of same age fed the same diet but at a maintenance level, once a day. Hepatic lipidosis led to an increase in plasma triacylglycerol (TG), very low density lipoprotein (VLDL) and low density lipoprotein (LDL), and an enrichment of LDL with TG and of high density lipoprotein (HDL) with cholesterol, suggesting that VLDL secretion is enhanced, VLDL and LDL catabolism is lowered, and lipoprotein exchanges are impaired in FHL. This study also showed that cholesterolaemia is increased in cats fed at a dietary rhythm of one meal per day compared to ad libitum feeding.

Myopathy and hepatic lipidosis in weaned lambs due to vitamin E deficiency

A sheep flock experienced losses in weaned lambs from myopathy and hepatic lipidosis. Investigation revealed painful ambulation, illthrift, and unexpected death in lambs with normal selenium levels, deficient vitamin E levels, and elevated muscle and liver enzyme levels. Vitamin E deficiency should be considered when investigating myopathy and illthrift in lambs.

Hepatic lipidosis in pregnant captive American bison (Bison bison)

Hepatic lipidosis, a hallmark lesion of lipid mobilization disorders in ruminants, was noted in four 3-year-old, pregnant bison (Bison bison) after periods of anorexia that progressed to recumbency and death. The affected bison were part of a herd at the National Animal Disease Center (NADC) that was used for brucellosis vaccine research. Microscopically, the liver contained swollen hepatocytes with numerous, variably sized, round, smoothly contoured vacuoles that displaced cytoplasmic structures. Hepatocytes in all zones of the lobule were affected equally. Hypoglycemia, decreased total carbon dioxide, elevated gamma-glutamyltransferase, elevated alkaline phosphatase, and increased nonesterified fatty acid levels were noted. As in the case of cattle, altered nutritional demands of late gestation combined with management factors such as obesity, nutrition, stress, and concomitant disease may be critical in the pathophysiology of lipid mobilization disorders in bison. Additionally, stressors unique to this research herd likely contributed to fatal hepatic lipidosis.

Combined corneal lipid and calcium degeneration in a dog with hyperadrenocorticism: a case report

Corneal degeneration may occur with a deposition of lipids or calcium, or both. Calcareous and lipid degeneration may be either primary or secondary, associated with systemic diseases such as primary hyperlipidemia, hyperlipidemia associated with hyperadrenocorticism, and hypothyroidism. The authors report a case of bilateral corneal lipid and calcium degeneration in a 7-year-old female Poodle with hyperadrenocorticism. The condition worsened with Lysodren therapy but responded to surgical excision.

Dietary L-carnitine supplementation in obese cats alters carnitine metabolism and decreases ketosis during fasting and induced hepatic lipidosis

This study was designed to determine whether dietary carnitine supplement could protect cats from ketosis and improve carnitine and lipid metabolism in experimental feline hepatic lipidosis (FHL). Lean spayed queens received a diet containing 40 (CL group, n = 7) or 1000 (CH group, n = 4) mg/kg of L-carnitine during obesity development. Plasma fatty acid, beta-hydroxybutyrate and carnitine, and liver and muscle carnitine concentrations were measured during experimental induction of FHL and after treatment. In control cats (CL group), fasting and FHL increased the plasma concentrations of fatty acids two- to threefold (P < 0.0001) and beta-hydroxybutyrate > 10-fold (from a basal 0.22 +/- 0.03 to 1.70 +/- 0.73 after 3 wk fasting and 3.13 +/- 0.49 mmol/L during FHL). In carnitine-supplemented cats, these variables increased significantly (P < 0.0001) only during FHL (beta-hydroxybutyrate, 1.42 +/- 0.17 mmol/L). L-Carnitine supplementation significantly increased plasma, muscle and liver carnitine concentrations. Liver carnitine concentration increased dramatically from the obese state to FHL in nonsupplemented cats, but not in supplemented cats, which suggests de novo synthesis of carnitine from endogenous amino acids in control cats and reversible storage in supplemented cats. These results demonstrate the protective effect of a dietary L-carnitine supplement against fasting ketosis during obesity induction. Increasing the L-carnitine level of diets in cats with low energy requirements, such as after neutering, and a high risk of obesity could therefore be recommended.

Corneal lipid deposition in Cuban tree frogs (Osteopilus septentrionalis) and its relationship to serum lipids: an experimental study

To evaluate the association between corneal lipid infiltration (corneal arcus) and dietary cholesterol in Cuban tree frogs (Osteopilus septentrionalis), 47 wild-caught frogs were fed diets of either regular or high-cholesterol crickets containing 0.7% and 1.7% cholesterol dry matter, respectively. Serum total cholesterol and triglycerides were measured when the frogs were euthanized after 17 mo. In a subsample of frogs, serum lipoproteins were characterized using high-performance liquid chromatography. The first case of corneal lipid deposition occurred in a female frog after 13 mo on the high-cholesterol diet. In the subsequent 4 mo, 5/11 males and 11/35 females developed the disease. Four of these affected frogs were females on the regular diet. Frogs with corneal lipid deposition had elevated serum total cholesterol (27.3 +/- 19.8 mmol/L) and low-density lipoproteins (LDL, 17.8 +/- 18.9 mmol/L) compared with unaffected captive frogs (16.5 +/- 20.4 and 9.0 +/- 7.6 mmol/L, respectively). Corneal lipid deposition was more prevalent in frogs on the high-cholesterol diet, and this group had higher serum total cholesterol (34.1 +/- 15.2 mmol/L in females, 22.8 +/- 14.8 mmol/L in males) than did frogs on the diet of regular crickets (12.3 +/- 8.7 mmol/L in females, 10.4 +/- 3.1 mmol/L in males). Captive frogs on both diets had higher serum total cholesterol than did wild frogs (3.1 +/- 2.1 mmo/L in females, 5.3 +/- 2.6 mmo/L in males). This additional serum cholesterol was primarily carried on very low-density lipoproteins (VLDL) and LDL rather than high-density lipoproteins (HDL), as indicated by the significantly higher ratio of VLDL cholesterol and LDL cholesterol over HDL cholesterol in captive frogs compared with wild frogs. Elevation in this ratio was significantly higher in captive females than in captive males. There was no evidence that increased serum cholesterol in captive females was directly related to the process of vitellogenesis.

Metabolic and hormonal alterations in cats with hepatic lipidosis

Hepatic lipidosis in cats is a commonly diagnosed hepatobiliary disease of unknown cause. The purpose of this prospective study was to characterize the blood hormone and lipid status of cats with hepatic lipidosis, and to compare this status to that of cats with other types of liver disease and to control cats. Twenty-three cats with hepatic disease were assigned to 1 of 2 groups on the basis of cytopathologic or histopathologic examination of the liver: group 1, hepatic lipidosis (n = 18); or group 2, cholangiohepatitis (n = 5). Ten healthy young adult cats were used as controls. Food was withheld from control animals for 24 hours before blood collection. Concentrations of plasma glucagon and serum insulin, cortisol, thyroxine, triglycerides, cholesterol, phospholipids, and nonesterified fatty acids (NEFAs) were determined in all cats, in addition to routine hematologic and serum biochemical testing. Cats with hepatic lipidosis had higher serum NEFA concentrations than cats with cholangiohepatitis or control cats (P < .05). Cats with cholangiohepatitis had higher serum cholesterol and phospholipid concentrations than those of cats with lipidosis or control cats (P < .05); their plasma glucagon concentrations were higher than those of control cats (P < .05), but were not different from those of cats with hepatic lipidosis. Serum insulin concentrations were significantly higher in control cats than in diseased cats (P < .05), but neither serum insulin nor the insulin to glucagon ratio was significantly different among the cats with hepatic disease. The high concentration of NEFAs in cats with hepatic lipidosis suggests that at least 1 factor in the pathogenesis of this syndrome may involve the regulation of hormone-sensitive lipase.

Fine-needle aspirate cytology suggesting hepatic lipidosis in four cats with infiltrative hepatic disease

Four cats are reported in which cytology smears obtained by ultrasound-guided fine needle aspiration of the liver were interpreted as indicative of hepatic lipidosis. However, histopathology of hepatic tissue samples obtained with Tru-Cut-like needles or wedge biopsy revealed that the cats had inflammatory or neoplastic hepatic disease causing their clinical signs. Fine needle aspiration and cytology may not detect infiltrative lesions, particularly those that are nodular, multifocal, or localised around the portal regions. Fine needle aspirate cytology is a useful diagnostic procedure with many advantages, but care must be taken to avoid diagnosing hepatic lipidosis as the cause of illness when an infiltrative lesion is responsible.

Necropsy and histopathologic findings in 14 African hedgehogs (Atelerix albiventris): a retrospective study

From fiscal years 1992 through 1996, 14 African hedgehog (Atelerix albiventris) cases were submitted to the Animal Disease Diagnostic Laboratory at Purdue University. The most common diagnoses were splenic extramedullary hematopoiesis (91%), hepatic lipidosis (50%), renal disease (50%), and neoplastic disease (29%). Other less frequent necropsy findings were myocarditis (21%), colitis (14%), bacterial septicemia (14%), and pneumonia (14%). The data indicate that splenic extramedullary hematopoiesis, hepatic lipidosis, renal disease, and neoplasms are frequent postmortem findings in hedgehogs.

Hepatic lipidosis associated with cobalt deficiency in Omani goats

Livers from 36 of 684 (5.3%) apparently healthy goats examined at an abattoir in the greater Muscat area of Oman exhibited gross pathological findings characterized by extremely pale, friable, fatty livers encompassing the entire organ. Histopathologically, diffuse hepatic lipidosis and occasional bile duct proliferation were observed. Periodic acid Schiff-positive, diastase-resistant pigment was observed in the macrophages lining the sinusoids. These histopathological lesions were consistent with those characteristic of ovine white liver disease. Cobalt analysis revealed that normal livers had six times more cobalt and a 3-fold less fat content than those measured in the fatty livers. This is the first report of an association between cobalt deficiency and hepatic lipidosis in Omani goats.

Hepatic lipidosis in llamas and alpacas: 31 cases (1991-1997)

OBJECTIVE

To identify factors associated with hepatic lipidosis (HL) in llamas and alpacas.

DESIGN

Retrospective case series.

ANIMALS

30 llamas and 1 alpaca.

PROCEDURES

Medical records were searched to identify llamas or alpacas in which a histologic diagnosis of HL was made. Information was retrieved on signalment, history, clinical and laboratory findings, and results of necropsy or examination of biopsy specimens. Data were analyzed using descriptive statistics and chi 2 analyses.

RESULTS

Females were affected more often than males; however, the sex distribution was not different from that of the camelid population in the diagnostic laboratory's database. Fifty-four percent of the females were pregnant, and 46% were lactating. Most affected camelids were 6 to 10 years old. Anorexia and recent weight loss were common (51.6% of camelids). An infective agent was found in only one ilama, and toxins and mineral deficiencies were not identified. The most common abnormalities on serum biochemical analysis were a high concentration of bile acids, high activities of gamma-glutamyltransferase (GGT) and aspartate aminotransferase (AST), and hypoproteinemia. Concentrations of nonesterified fatty acids (NEFA) and beta-hydroxybutyrate (beta-HB) were high in those camelids in which these compounds were assayed. Twenty-nine camelids did not survive.

CLINICAL IMPLICATIONS

Sick camelids should be considered at risk for developing HL, especially those with anorexia or the metabolic demands of pregnancy and lactation. Other stresses also appear to contribute. High concentrations of NEFA, beta-HB, and bile acids; high activities of GGT and AST; and hypoproteinemia may indicate that HL has developed.

Reduced lymphoid response to skin allotransplants in cows with hepatic lipidosis

The immune responsiveness of cows with hepatic lipidosis (fatty liver) in comparison to control cows with a normal liver fat content was tested by applying skin allotransplants to the skin of the back of cows on day 3 after parturition. Immunoreactivity was determined by semiquantitative counting of the number of infiltrating lymphocytes in the recipient skin adjacent to the allotransplants during a period of 21 days. There were more invading lymphocytes in samples from control cows than there were in samples from cows with hepatic lipidosis. It was concluded that cows with hepatic lipidosis have a reduced lymphoid response to skin allotransplants.

Qualitative ultrasonography of the liver in obese cats

A prospective study was undertaken to compare the relative echogenicity of the liver and the fat of the falciform ligament in two groups of clinically normal obese cats. In the first group of cats, four of eight normal weight cats were fed a high calorie diet ad libitum for a 12 week period at which time they were considered obese. The liver was hyperechoic when compared to the adjacent fat of the falciform ligament in the obese cats. In the second group of cats, the body condition of a group of eight clinically normal cats was subjectively graded. On ultrasonographic examination, the liver of those cats considered to be overweight were hyperechoic compared to the adjacent fat of the falciform ligament. Results from this study suggest that clinically normal obese cats may have a liver that is hyperechoic relative to the fat of the falciform ligament.

Diabetic ketosis and ketoacidosis in cats: 42 cases (1980-1995)

OBJECTIVE

To determine clinical signs, clinicopathologic abnormalities, prevalence of concurrent disease, treatment, complications of treatment, and outcome in cats with diabetic ketosis (DK) or diabetic ketoacidosis (DKA).

DESIGN

Retrospective study.

ANIMALS

42 cats with DK or DKA.

PROCEDURE

Medical records of diabetic cats with ketonuria were reviewed.

RESULTS

In 26 cats, diabetes was newly diagnosed; in 16, diabetes had been diagnosed previously and cats had been treated with insulin (n = 14) or sulfonylurea drugs (2). Common clinical findings were lethargy, anorexia, polyuria, polydipsia, and weight loss. Common laboratory findings were hyperglycemia, hyponatremia, hypochloremia, hypokalemia, hypocalcemia, hypophosphatemia, low total CO2 content, hyperosmolality, high serum alanine transaminase activity, azotemia, glycosuria, and ketonuria. Concurrent disorders were identified in 39 cats and included hepatic lipidosis, cholangiohepatitis, pancreatitis, chronic renal failure, urinary tract infection, and neoplasia. Treatment of DK and DKA included administration of regular crystalline (34 cats), NPH (6), or ultralente (2) insulin, intravenous (38) or subcutaneous (4) administration of fluids, and enterall parenteral or administration of antibiotics (42). Complications during treatment included abnormalities in serum electrolyte concentrations (27 cats), hemolytic anemia (4), hypoglycemia (3), and neurologic abnormalities unrelated to hypoglycemia (2). Eleven cats died or were euthanatized during the initial hospitalization period for treatment of DK or DKA. Azotemia, metabolic acidosis, and hyperosmolality were more severe in cats that died than in cats that survived. Differences in regard to treatment or complications were not apparent between cats that died and cats that survived. The 31 cats that survived were discharged 1 to 16 days (median, 5 days) after initiation of insulin treatment. Diabetic ketosis or ketoacidosis recurred in 13 (42%) of these cats.

CLINICAL IMPLICATIONS

A thorough diagnostic evaluation should be performed on cats with DK or DKA to identify concurrent disorders, formulate an appropriate treatment plan, and provide prognostic information to the owner.

Lipid composition of hepatic and adipose tissues from normal cats and from cats with idiopathic hepatic lipidosis

The purpose of this study was to characterize the lipid classes in hepatic and adipose tissues from cats with idiopathic hepatic lipidosis (IHL). Concentrations of triglyceride, phospholipid phosphorus, and free and total cholesterol were determined in lipid extracts of liver homogenates from 5 cats with IHL and 5 healthy control cats. Total fatty acid composition of liver and adipose tissue was also compared. Triglyceride accounted for 34% of liver by weight in cats with IHL (338 +/- 38 mg/g wet liver) versus 1% in control cats (9.9 +/- 1.0 mg/g wet liver, P < .001). The mass of cholesterol ester was significantly higher in triglyceride-free (TG-free) liver from cats with IHL (741 +/- 340 micrograms/g TG-free wet liver) compared to healthy cats (31 +/- 11 micrograms/g TG-free wet liver, P < .05). Total fatty acid composition of hepatic tissue in the 2 groups differed; palmitate was higher (19.5 +/- 1.1% of total fatty acids in cats with IHL versus 9.2 +/- 2.7% in controls, P < .05), stearate was lower (8.5 +/- 0.8% versus 16.8 +/- 1.1%, P < .05), oleate was higher (41.2 +/- 1.6% versus 31.1 +/- 1.8%, P < .05), and arachidonate was lower (1.2 +/- 0.2% versus 6.0 +/- 0.9%, P < .05). The total fatty acid composition of adipose tissue also differed between the 2 groups; palmitate was higher (26.2 +/- 1.2% in cats with IHL versus 21.3 +/- 0.6% in controls, P < .05), total monounsaturated fatty acids were higher (48.4 +/- 1.0% versus 45.0 +/- 0.8%, P < .05), linolenate was lower (13.3 +/- 1.6% versus 17.5 +/- 0.9%, P < .05), total (n-6) fatty acids were lower (13.8 +/- 1.38% versus 18.4 +/- 0.83%, P < .05), linolenate was lower (0.2 +/- 0.04% versus 0.7 +/- 0.06%, P < .06), and total (n-3) fatty acids were lower (0.3 +/- 0.02% versus 1.3 +/- 0.32%, P < .05). The fatty acid composition of both liver and adipose tissue was similar for stearate, oleate, linoleate, and linolenate in cats with IHL. These results support the hypothesis that the origin of hepatic triglyceride in cats with IHL is the mobilization of fatty acids from adipose tissue.

Hepatic lipidosis in anorectic, lactating holstein cattle: a retrospective study of serum biochemical abnormalities

The association between hepatic lipidosis (HL) and disease in 59 anorectic, ketotic, lactating Holstein heifers and cows was investigated. Severe HL, as determined by histologic evaluation of liver tissue, was present in 46 animals; only half of these animals required intensive treatment for ketosis, and only half had serum biochemical evidence of liver disease, as determined by the presence of a last value of 2-fold or greater than the upper limit of the reference ranges for at least 2 of the 4 serum tests: gamma-glutamyl transferase, aspartate aminotransferase, and sorbitol dehydrogenase activities and bile acid concentrations. Most cattle with biochemical evidence of liver disease and severe HL had been lactating for 14 or more days. Cows that required intensive treatment inconsistently had serum biochemical evidence of liver disease. Although cattle with severe HL had significantly higher serum bilirubin concentrations and aspartate aminotransferase and sorbitol dehydrogenase activities than cattle with less severe lipidosis, the specificity of abnormally high serum sorbitol dehydrogenase activity or bilirubin concentration for severe lipidosis was only 8%. Abnormally high serum aspartate aminotransferase activity was 83% sensitive and 62% specific for severe lipidosis. Serum glucose and total carbon dioxide concentrations were significantly lower in cattle with severe lipidosis than in those with mild or moderate lipidosis, and low serum glucose or total carbon dioxide concentrations were rare in cattle without severe lipidosis. From these data, we conclude that the use of a single biochemical or histopathologic criterion to define severity of disease or degree of liver compromise in anorectic, ketotic cows results in the misidentification of many animals.

High feline trypsin-like immunoreactivity in a cat with pancreatitis and hepatic lipidosis

A 1.5-year-old domestic shorthair cat was examined because of vomiting and icterus. Clinicopathologic abnormalities included high alanine transaminase, alkaline phosphatase, and gamma-glutamyltransferase activities and high total bilirubin concentration. During abdominal ultrasonography, the left limb and body of the pancreas appeared hypoechoic, and a small quantity of peritoneal effusion was seen. The liver was diffusely hyperechoic, with echogenicity similar to that of the spleen, indicating hepatic lipidosis. Feline trypsin-like immunoreactivity was high, suggesting that the cat also had pancreatitis. The cat was treated with crystalloid fluids and was fed a protein-restricted diet via a percutaneous endoscopically placed gastrostomy tube. The cat's condition continued to deteriorate despite medical treatment, and it was euthanatized. Necropsy confirmed the clinical suspicion of acute pancreatitis and hepatic lipidosis. This case suggests that measurement of trypsin-like immunoreactivity may be useful in cats suspected of having pancreatitis.

Impaired specific immunoreactivity in cows with hepatic lipidosis

In this study, hepatic lipidosis in cows was experimentally induced by offering an energy surplus during the dry period. Liver triacylglycerol (TAG) was 16% in the experimental group. In the control group fed the same diet in restricted quantities, liver TAG was about 7%. The animals of both groups were vaccinated with tetanus vaccine at Day 3 after parturition. It was demonstrated that the cows with high liver TAG percentages had lower humoral and cellular (P < 0.05) immunological responses compared with the animals with low liver TAG levels at Day 14 after vaccination. The results obtained in the high TAG group support the notion that the frequent occurrence of aspecific infections in cows with hepatic lipidosis may be due to impaired immunoreactivity.

Nutrition and liver disease

Nutritional support is a key factor in the treatment of cats with hepatic disease. This is the only effective treatment in cats with hepatic lipidosis. The ideal diet would be one that fulfills all the basic energy and nutrient requirements of the patient, allows positive energy balance, provides all the nutrients necessary for liver regeneration, and prevents or aids the recovery from major complications of liver disease. Formulation of diets for cats with hepatobiliary diseases must also take into account their metabolic peculiarities. Anorexia is a common complication of liver disease and clinicians must take the necessary actions to ensure adequate energy and nutrient intake. No single diet will accommodate all patients and nutritional support must be adapted to each individual case based on the type of liver disease, extent of hepatic dysfunction, tolerance to dietary protein, and nutritional status.

Feline hepatic lipidosis

Hepatic lipidosis occurs when lipid mobilized to the liver exceeds lipid leaving the liver via formation of very-low-density lipoproteins or by oxidation. Hepatic lipidosis in cats is associated with overt liver dysfunction. In affected cats, excess lipid is mobilized to the liver because of starvation. Removal of hepatic lipid may be impaired because of protein malnutrition, a relative carnitine deficiency, or oxidative damage to peroxisomes and other hepatic organelles. Hepatic lipidosis occurs in adult cats, and is manifest by signs of weight loss, depression, vomiting, and icterus. Diagnosis is achieved by evaluating laboratory and diagnostic imaging data, in conjunction with a liver biopsy. Aggressive tube feeding is the treatment of choice. With this treatment, survival rates are 60% to 80%.

Studies on in vivo endotoxin plasma disappearance times in cattle

Endotoxin plasma disappearance (EPDT) times were determined by a modified Limulus amoebocyte lysate (LAL) assay technique after the intravenous administration of 25 micrograms E. coli 055:B5 endotoxin per kg b.w. to 22 Jersey cows. Clinically healthy cows (n = 6) cleared endotoxin from the plasma within 30 min. Cows pretreated with flunixin meglumine (n = 6) had 2-3 times longer plasma disappearance times, while cows pretreated with phenylbutazone (n = 6) had plasma disappearance times which were 6-12 times longer than the healthy control group. A fourth group comprised clinical cases of spontaneously developed hepatic lipidosis (n = 4). None of these cows were able to clear the injected endotoxin dose and one died before the end of the experiment. The acute phase response, described by leukocyte and thrombocyte counts and plasma glucose and zinc concentrations, was not statistically different between the four groups.

Clinical and pathological studies in horses with hepatic disease

In horses with hepatic necrosis, lipidosis, neoplasia and cirrhosis, progression of the disease was studied by serial measurements of total serum bile acid concentrations and of plasma glutamate dehydrogenase (GD) and gamma glutamyl transferase (gamma GT) and by liver biopsy. Plasma ammonia concentrations were significantly elevated compared to clinically normal horses, but such changes were not always accompanied by a decline in plasma urea concentration. A fall in plasma glucose concentration carried a guarded prognosis. These were all invaluable aids in early diagnosis and throughout the disease course. The study suggests that other factors, such as hypokalaemia, alkalosis, short chain volatile fatty acids, false and true neurotransmitters, may be important in the pathogenesis of hepatic coma in the horse.

Hyperlipidemia, hyperlipemia, and hepatic lipidosis in American miniature horses: 23 cases (1990-1994)

The medical records of 23 American Miniature Horses with hyperlipidemia, hyperlipemia, or hepatic lipidosis were reviewed. The most common clinical signs were anorexia and lethargy. The mean duration of clinical signs was 2.4 days. A primary disease was identified in 19 cases. Enterocolitis was the most common primary disease (n = 10). Intentional feed restriction, as part of treatment for colic, resulted in hyperlipemia in 2 horses and hyperlipidemia in 1. Four horses had primary hyperlipemia, 3 of which had signs of hepatoencephalopathy secondary to hepatic lipidosis. Dextrose, heparin, and insulin were the most common treatments. The overall survival was 61% (14/23). All horses with peak serum triglyceride concentrations > 1,200 mg/dl died or were euthanatized, whereas all but 1 with peak serum triglyceride concentrations < 1,200 mg/dl survived. These findings suggest that when American Miniature Horses, like other ponies and donkeys, are in a negative energy balance, they can rapidly develop hyperlipidemia or hyperlipemia. Early detection and treatment may improve survival.

Feline idiopathic hepatic lipidosis

Feline IHL is a severe hepatopathy that can be treated by aggressive nutritional support. Until the underlying mechanisms of protein and lipid metabolism are understood in both healthy and ill cats, dietary therapy remains supportive. It is likely that the pathogenesis of IHL in cats is multifactorial, involving both increased fatty acid mobilization to the liver and a defect in oxidation of fatty acids or removal of VLDL. It is also possible that individual variation may play a role in the development of this disease in cats undergoing starvation. Continued studies will focus on the unique pathways of hepatic metabolism in the cat, and how these pathways are altered, leading to hepatic lipid accumulation and clinical disease. Hopefully, these studies can be applied to the prevention or treatment of IHL in cats.

Serum bile acid concentrations in dairy cattle with hepatic lipidosis

This study was designed to evaluate serum bile acid measurements as indicatory, of liver function and/or hepatic fat infiltration in dairy cattle. Serum bile acid concentrations were measured in healthy dairy cattle at different stages of lactation after fasting or feeding. Bile acid concentrations were compared with liver fat content and sulfobromophthalein (BSP) half-life (T 1/2). Serum bile acid concentrations were higher in cows in early lactation and with higher daily milk production. Compared with prefasting values, bile acid concentrations were decreased at 8, 14, and 24 hours of fasting. Blood samples from fed cows at 1- to 2-hour intervals had wide and inconsistent variations in bile acid concentration. Because serum bile acids correlated well with BSP T 1/2, it is suggested that both measurements evaluate a similar aspect of liver function. Neither bile acids nor BSP T 1/2 correlated with differences in liver fat content among cows. Because of large variability in serum bile acid concentrations in fed cows and the lack of correlation of measured values with liver fat content, bile acid determinations do not appear useful for showing changes in hepatic function in fed cows with subclinical hepatic lipidosis nor serve as a screening test for this condition.

Dietary menhaden oil contributes to hepatic lipidosis in laying hens

Clinical and epidemiological investigations have indicated that there may be substantial human cardiovascular benefits associated with increased consumption of n-3 fatty acids commonly found in fish oils. Recent studies have indicated that egg yolk n-3 fatty acid content is significantly increased when hens are fed diets enriched with selected fish oils such as menhaden oil (MO). In the present study, reproductively active females but not males exhibited increased hepatic lipidosis following 6 mo of feeding 3% MO. Hens fed 3% animal-vegetable oil (AV) did not exhibit hepatic lipid accumulation. Serum triglyceride and cholesterol concentrations were reduced (P < or = .05) in hens fed MO. Subsequently, yolk and total egg weights of hens fed MO were decreased as compared with those of hens fed AV. A significant interaction of dietary MO and exogenous 17 beta-estradiol was noted among chick liver and gallbladder weights. These data suggest that dietary MO and estradiol may interact in a manner that enhances the lipogenic activity of the liver, thereby inducing hepatic lipidosis in laying hens.

Hepatic lipidosis in turkeys

Two flocks of 14,000 twenty-week-old turkey hens each experienced increased mortality due to hepatic lipidosis. Some hens showed signs of dyspnea and cyanosis before death. Necropsy revealed dark muscles and enlarged livers with pale areas and numerous hemorrhages. Petechial and ecchymotic hemorrhages were also found on the abdominal fat and epicardium. Lung congestion and edema were prominent. In the heart and blood vessels, the blood was uncoagulated. Mortality was elevated for 12 days and resulted in the death of 0.7% of the turkey hens in one flock and 1.7% in the other. Vitamin E administered in water at a dose of 25 IU per hen appeared to reduce mortality. The nutritional and environmental factors that may contribute to the development of hepatic lipidosis in turkeys are discussed.

Diet-induced lipofuscin and ceroid formation in growing pigs

Seven piglets, aged 2 weeks at the beginning of the experiment, were fed a diet lacking antioxidants (vitamin E and selenium) and enriched with thermally oxidated cod liver oil (the peroxide value of which was 310 meqv/kg). From one month before to 4 weeks after farrowing (weaning) the sow also received the experimental diet. One pig died at 9 days of age, due to degeneration of the parenchymal tissues. The oxidative stress produced was aggravated in four of the seven remaining pigs by giving them an injection of iron-dextran (300 mg) one day before the animals were killed for necropsy at the age of 2 months. The three other piglets were given an injection of a control saline solution. The nutritional myodegeneration produced ('white muscle disease') was characterized by a pale, yellowish colour and translucence of skeletal muscle, with degeneration, including swelling of the muscle fibres and slackening of the fibrillar pattern. The arrangement of nuclei in chains indicated repair. Ultrastructurally, skeletal muscle showed vacuolization of the sarcoplasmic reticulum, irregularities in the mitochondria and focal dissolution of myofibrils. The sarcoplasmic reticulum displayed condensation and lamellar formations. Hyaline degeneration of the heart muscle occurred both in iron-treated and control pigs, and in six animals a yellowish pigment resembling lipofuscin and ceroid was observed. Ultrastructurally, the ceroid deposits appeared as myelin-like figures. The livers were pale and brittle, four with centrilobular degeneration. By light microscopy, lipidosis was distinguished in four and ceroid accumulations in three pigs. Thiobarbituric-acid-reactive substances, creatine kinase activity and iron increased significantly in the serum as a result of the injection of iron-dextran.

A retrospective study of 77 cats with severe hepatic lipidosis: 1975-1990

The physical, clinicopathologic, and survival rates of 77 cats with severe spontaneous hepatic lipidosis are detailed in this report. Cats were subdivided into groups designated as idiopathic lipidosis if no other disease process was recognized, or secondary lipidosis if another disease process was diagnosed. Cats were also subdivided into groups designated as survivors or nonsurvivors on the basis of successful recuperation at 4 months after initial diagnosis. Differences between disease and survival groups were evaluated for significance. Overall, more female cats and middle-aged cats were affected. Presenting complaints of vomiting, anorexia, weakness, and weight loss were common. Physical assessment of most cats showed obvious hepatomegaly, jaundice, dehydration, and a weight loss > or = 25% of usual body weight. Neurobehavioral signs indicative of hepatic encephalopathy, other than ptyalism and depression, were rare. Clinicopathologic features are characterized by hyperbilirubinemia and increased activities of serum ALT, AST, and ALP, with only small if any increase in gamma GT activity. Clinical features distinguishing cats with hepatic lipidosis from those with other serious cholestatic disorders include absence of hyperglobulinemia and low gamma GT activity relative to ALP activity. Although coagulation tests were abnormal in 45% of cats tested (n = 44), few cats showed clinical bleeding tendencies. Most cats received prophylactic vitamin K1 therapy. Forty two cats received aggressive nutritional and supportive care and of these 55% survived. Cats with idiopathic disease were significantly younger, had significantly higher ALP activity and bilirubin concentration, and had a slightly better survival rate than cats with secondary lipidosis. Low PCV, hypokalemia, and an older age were significantly related to nonsurvival. Because of the variety of diets and food supplements used in case management, the influence of nutritional factors on survival could not be evaluated.