Research Abstracts of Interest to Llama Owners
The ILR has long felt it necessary to support and distribute information concerning camelid research. Following are 2 abstracts of concern to llama owners. If you wish more information, you will need to contact the American Journal of Veterinary Research.
Assessment of the effects of exogenous long-acting insulin on glucose tolerance in alpacas
Determination of electrocardiographic parameters in healthy llamas and alpacas
The objective of this research was to describe the metabolic effects of epinephrine administration in New World camelids and investigate whether these effects are influenced by administration of insulin.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.Administration of epinephrine induced mobilization of glucose, triglycerides, nonesterified fatty acids, and â-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. 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)
Jaime Ueda, BA; Christopher K. Cebra, VMD, MS; Susan J. Tornquist, DVM, PhD
The objective of this research was to evaluate the effects of long-acting insulin on glucose clearance in alpacas. 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. 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 insulin-treated alpacas from 105 through 300 minutes. 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)
Marc S. Kraus, DVM; Clay A. Calvert, DVM; Alan W. Spier, DVM, PhD; Kathryn M. Meurs, DVM, PhD; David E. Anderson, DVM *
The objective of this research was to determine electrocardiographic parameters in healthy llamas and alpacas. 23 llamas and 12 alpacas were studied. Electrocardiography was performed in nonsedated standing llamas and alpacas by use of multiple simultaneous lead recording (bipolar limb, unipolar augmented limb, and unipolar precordial leads).Common features of ECGs of llamas and alpacas included low voltage of QRS complexes, variable morphology of QRS complexes among camelids, and mean depolarization vectors (mean electrical axes) that were directed dorsocranially and to the right. Durations of the QT interval and ST segment were negatively correlated with heart rate.ECGs of acceptable quality can be consistently recorded in nonsedated standing llamas and alpacas. Features of ECGs in llamas and alpacas are similar to those of other ruminants. Changes in the morphology of the QRS complexes and mean electrical axis are unlikely to be sensitive indicators of ventricular enlargement in llamas and alpacas. (Am J Vet Res 2004;65:1719-1723)