tolerance in alpacas

12-20-04        From David Anderson DVM  Ohio State University:

Assessment of the effects of exogenous long-acting insulin on glucose
tolerance in alpacas
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)

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7-2-04  From David Anderson DVM  Ohio State University

Assessment of the effects of feed restriction and amino acid supplementation
Christopher K. Cebra, VMD, MA, MS; Susan J. Tornquist, DVM, PhD; Rebecca M.
Jester, BS; Calogero Stelletta, DVM *
 American  Journal of Veterinary Research 2004;65:996-1001

The objective of this study was to assess the effects of prolonged feed
deprivation on glucose tolerance, insulin secretion, and lipid homeostasis
in llamas.On each of 2 consecutive days, food was withheld from the llamas
for 8 hours. Blood samples were collected before and 5, 15, 30, 45, 60, 120,
and 240 minutes after IV injection of dextrose (0.5 g/kg) for determination
of plasma insulin and serum glucose, triglyceride, and nonesterified fatty
acid concentrations. Between experimental periods, the llamas received
supplemental amino acids IV (185 mg/kg in solution). The llamas were then
fed a limited diet (grass hay, 0.25% of body weight daily) for 23 days,
after which the experimental procedures were repeated.Feed restriction
decreased glucose tolerance and had slight effects on insulin secretion in
llamas. Basal lipid fractions were higher after feed restriction, but
dextrose administration resulted in similar reductions in serum lipid
concentrations with and without feed restriction. Insulin secretion was
decreased on the second day of each study period, which lessened reduction
of serum lipid concentrations but did not affect glucose tolerance. Despite
having a comparatively competent pancreatic response, feed-restricted llamas
assimilated dextrose via an IV bolus more slowly than did llamas on full
rations. However, repeated administration of dextrose reduced insulin
secretion and could promote hyperglycemia and fat mobilization. These
findings suggested that veterinarians should use alternative methods of
supplying energy to camelids with long-term reduced feed intake or consider
administering agents to improve the assimilation of glucose.
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