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- Author or Editor: Christopher K. Cebra x
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Objective—To describe the metabolic effects of epinephrine administration in New World camelids and investigate whether these effects are influenced by administration of insulin.
Animals—6 llamas and 8 alpacas (all adult castrated males).
Procedure—Prior to each experiment, food was withheld from camelids for 8 hours. On each of 2 consecutive days, alpacas were administered epinephrine (10 mg/kg, IM; time 0); alpacas were randomly assigned to receive regular insulin (0.2 U/kg, IV) immediately after epinephrine administration on one of those days. In llamas, the experiment was performed once after administration of epinephrine only. At 0, 30, 60, 90, 120, 150, 180, 210, and 240 minutes after treatment, blood samples were collected and several serum or plasma biochemical variables were assessed; in addition, plasma samples from llamas were assessed for insulin concentrations. Data were compared between days (alpacas only) and between time points.
Results—Administration of epinephrine induced mobilization of glucose, triglycerides, nonesterified fatty acids, and β-hydroxybutyrate. A small increase in endogenous insulin concentration was detected in epinephrine-treated llamas, compared with baseline values. Overall, insulin administration decreased, negated, or delayed the epinephrine-associated increases in serum or plasma concentrations of circulating energy substrates, except that it augmented the epinephrine-associated increase in concentration of triglycerides.
Conclusions and Clinical Relevance—Epinephrine appeared to mobilize energy substrates in camelids and hence may be involved in the pathogenesis of disorders of glucose and fat metabolism. Insulin appeared to antagonize most of these effects, and its administration may have therapeutic value in camelids. (Am J Vet Res 2004;65:1692–1696)
Objective—To investigate glucose tolerance and insulin sensitivity in llama crias.
Animals—7 llamas (age range, 14 to 30 days).
Procedure—On each of 2 sequential days, crias were administered glucose (0.5 g/kg) via rapid IV injection. On 1 day (randomly determined for each cria), regular insulin (0.2 U/kg) or 0.9% NaCl solution (0.002 mL/kg) was administered IV 15 minutes after glucose administration. Blood samples were collected before (baseline) and at 5, 15, 30, 45, 60, 90, 120, 180, and 240 minutes after glucose administration for determination of plasma glucose and insulin concentrations; fractional turnover rates and plasma half-life of glucose were calculated. The data were compared over time and between days (ie, between glucose treatments with and without insulin administration).
Results—A peak plasma glucose concentration of 342 ± 47 mg/dL was detected at 5 minutes after glucose administration and llamas cleared glucose from plasma within 60 minutes; at 15 minutes, plasma insulin concentration attained a peak value of 33 ± 13 µU/mL (ie, triple the baseline value). During the 15- to 45-minute interval, fractional turnover rate of glucose was 1.10 ± 0.24%/min and plasma half-life was 65.7 ± 13.4 minutes. Insulin significantly increased glucose turnover and resulted in hypoglycemia within 75 minutes of administration.
Conclusions and Clinical Relevance—Healthy immature llamas have glucose tolerance and insulin sensitivity superior to that of adults. However, whether sick crias retain the pancreatic sufficiency and tissue responsiveness that are likely responsible for the rapid glucose clearance in healthy individuals is not known. (Am J Vet Res 2005;66:1013–1017)
Objective—To compare relative sensitivity and overall yields of various methods of fecal examination for gastrointestinal parasites in llamas and alpacas.
Sample Population—Fecal samples from 42 alpacas and 62 llamas.
Procedures—Fecal samples were analyzed via direct smear, a modified McMaster technique with sucrose solution or saturated saline (approx 36% NaCl) solution, and a centrifugation-flotation procedure. McMaster flotation chambers were examined 15 and 60 minutes after loading. Centrifugation-flotation samples were examined after 10 and 60 minutes of flotation. The proportions of samples with positive results and concentrations of parasites were compared among methods.
Results—The centrifugation-flotation technique yielded more positive results than other methods for all parasites except small coccidia. Longer flotation time increased the proportion of positive results and parasite concentrations for all parasites except Nematodirus spp. Longer time in the McMaster chamber made little difference. By use of the modified McMaster technique, sucrose solution yielded more positive results for Trichuris spp, Eimeria macusaniensis, and strongyles, whereas saline solution yielded more positive results for Nematodirus spp and small coccidia. The saline solution McMaster test yielded more positive results for small coccidia than did most other methods, and the sucrose McMaster technique yielded more positive results for Trichuris spp.
Conclusions and Clinical Relevance—The centrifugation-flotation technique appeared to offer clear advantages in detecting infection with E macusaniensis, Trichuris spp, Nematodirus spp, and capillarids. The saline McMaster technique appeared to offer an advantage in detecting small coccidia.
Objective—To test the ability of a nested PCR assay to detect Eimeria macusaniensis at various stages of infection in alpacas.
Animals—4 healthy adult alpacas with no detectable E macusaniensis.
Procedures—Alpacas were inoculated with 2 × 104 sporulated oocysts. Serial fecal samples collected during the next 38 days were tested via sucrose flotation and PCR assay.
Results—Oocyst passage was detected via fecal flotation in all 4 alpacas 31 to 35 days after inoculation. Three had positive results for PCR assays on samples obtained 7 to 14 days after inoculation. One alpaca subsequently was removed from the study because of weight loss and inappetence. Two remaining alpacas had positive PCR reactions 28 and 31 days after inoculation, up to 7 days before oocysts appeared in the feces. All fecal samples with positive results for flotation also had positive results for PCR assay.
Conclusions and Clinical Relevance—The PCR assay was able to detect early (7 to 14 days) and late (28 to 31 days) prepatent infection. These positive results suggested that the assay could have been detecting DNA unassociated with oocysts or detecting shedding earlier than has been previously recognized. The gap between the early and late detection periods may not be evident in alpacas receiving a larger or continuous inoculum, as might occur with natural infection. Use of a PCR assay for analysis of fecal samples may be valuable for detection of E macusaniensis during the prepatent period, thus aiding in the identification and control of infected animals.
Objective—To evaluate the effects of long-acting insulin on glucose clearance in alpacas.
Animals—8 adult castrated alpacas.
Procedure—On 2 days, food was withheld from alpacas for 8 hours. Alpacas were randomly allocated to receive an SC injection of long-acting insulin (0.4 U/kg) or saline (0.9% NaCl) solution 1 hour before the first of 3 administrations of glucose (at 60, 480, and 1,200 minutes after treatment) on day 1 and the alternate treatment and procedure on day 2. Plasma glucose concentration was determined before and 15, 45, 120, and 240 minutes after each glucose administration, and fractional turnover rates were calculated. The data were compared between alpacas with and without insulin administration and among the 3 glucose administrations for each day.
Results—Compared with sham-treated alpacas, insulin-treated alpacas had significantly lower blood glucose concentrations from 180 to 600 minutes after treatment; they also had glucose concentrations significantly below baseline values from 120 to 480 minutes, at which time the mean glucose concentration was in the hypoglycemic range. Also, mean fractional turnover of glucose was significantly higher in insulintreated alpacas from 105 through 300 minutes.
Conclusions and Clinical Relevance—Compared with known effects of regular insulin in alpacas, the action of long-acting insulin was of slower onset but longer lasting; its administration may induce hypoglycemia, even in alpacas that receive glucose. To maintain the hypoglycemic effect, long-acting insulin may have to be administered more than once daily and blood glucose concentration should be monitored to avoid hypoglycemic complications in alpacas. (Am J Vet Res 2004;65:1688–1691)
Objective—To characterize signalment, clinical signs of disease, and clinical response to insulin in equids with hypertriglyceridemia.
Design—Retrospective case series.
Animals—20 horses, 17 ponies, and 7 donkeys with hypertriglyceridemia.
Procedures—For analysis of medical record data, horses, donkeys, and ponies with multiple serum or plasma triglycerides measurements were separated into groups. Hypertriglyceridemic equids that were (HT-I; n = 14) or were not (HT-N; 10) treated with insulin consisted of equids with an initial triglycerides concentration > 44 mg/dL but < 500 mg/dL. Equids with an initial triglycerides concentration > 500 mg/dL, all of which were treated with insulin, constituted the lipemic group (LIP-I; 20). Each group included a full range of ages. Pretreatment and posttreatment values from serum or plasma biochemical analyses were compared among groups.
Results—No age predilection for hypertriglyceridemia was apparent. Of the 29 female equids, only 7 (24%) were lactating or pregnant. Multiple illnesses were diagnosed in hypertriglyceridemic equids, including colitis (14/44; 32%) and colic (9/44; 20%). Many breeds were affected, including 16 (36%) American Miniature Horses and 9 (20%) Arabians or Arabian crossbreds. The mean posttreatment triglycerides concentration was not significantly different from the initial value in HT-N equids (175 vs 125 mg/dL) but was significantly lower than the pretreatment triglycerides concentration in HT-I (252 vs 55 mg/dL) and LIP-I (872 vs 87 mg/dL) equids.
Conclusions and Clinical Relevance—Equids of all ages and sexes with various diseases had hypertriglyceridemia. Insulin treatment decreased the triglycerides concentrations in affected equids.
Objective—To assess the feasibility and usefulness of CT enterography to evaluate the gastrointestinal tract in clinically normal llamas and alpacas.
Design—Prospective observational study.
Animals—7 clinically normal alpacas and 8 clinically normal llamas.
Procedures—The imaging protocol included orogastric administration of iodinated contrast material mixed with water. Three hours later, helical CT scanning was performed of the entire abdomen with transverse and multiplanar sagittal and dorsal projections before and after IV iodinated contrast agent injection.
Results—Both oral and IV contrast agents were well tolerated, and no adverse reactions were observed. Transverse images depicted the gastrointestinal tract and pancreas in the short axis; however, dorsal and sagittal projections aided in localizing and differentiating the various gastrointestinal segments, including the pancreas. In all camelids, the wall of the gastrointestinal tract was well differentiated. In all but 2 camelids, all gastrointestinal segments were well visualized and differentiated. In those 2 animals, the cecum was difficult to identify. Good distention of the small intestine was achieved by use of the oral contrast agent. The dorsal projections were useful to identify the pancreas in its entire length.
Conclusions and Clinical Relevance—The present study supplied new information about gastrointestinal wall thickness, intestinal diameter, and location of the pancreas and ileocecocolic junction in alpacas and llamas. Multiplanar contrast-enhanced CT was useful to reveal the various segments of the gastrointestinal tract, pancreas, and abdominal lymph nodes. The shorter time delay before imaging, compared with the delay with conventional barium studies, makes this technique complementary or superior to conventional radiographic or ultrasonographic studies for evaluation of the gastrointestinal tract.
Objective—To evaluate camelids with hypertriglyceridemia with regard to signalment, clinical features of disease, and response to treatment with insulin.
Design—Retrospective case series.
Animals—23 alpacas and 8 llamas with hypertriglyceridemia.
Procedures—For analysis of medical record data, 20 hypertriglyceridemic camelids with multiple recorded measurements of serum or plasma triglycerides concentration were classified as follows: those with an initial triglycerides concentration > 60 to ≥ 500 mg/dL that were or were not treated with insulin (HT-I and HT-N camelids, respectively) and those with an initial triglycerides concentration > 500 mg/dL that were treated with insulin (lipemic [LIP-I] camelids). Only 1 recorded triglycerides concentration was available for an additional 11 hypertriglyceridemic camelids; data from those records were included in the characterization of signalment and clinical features of disease.
Results—Compared with the general population of hospitalized camelids, hypertriglyceridemic camelids did not differ significantly with respect to age or sex. Of 22 female camelids, only 7 were lactating or pregnant. Serum or plasma triglycerides concentrations in HT-N and HT-I camelids did not differ significantly at admission, but triglycerides concentrations in HT-I camelids decreased significantly after insulin treatment. Posttreatment triglycerides concentrations in HT-I camelids were significantly lower than those in HT-N camelids. During the period of hospitalization, triglycerides concentrations in HT-N camelids increased, whereas those in LIP-I camelids decreased significantly.
Conclusions and Clinical Relevance—Results indicated that hypertriglyceridemia affects llamas and alpacas of all ages and both sexes. Insulin treatment may reduce serum or plasma triglycerides concentrations in camelids with hypertriglyceridemia.