Northern Prairie Wildlife Research Center
Prolonged Winter Undernutrition and the Interpretation of Urinary Allantoin:Creatinine
Ratios in White-tailed Deer
Results
Initially, recent MEIs did not differ between the treated and control deer (H0:
equal intercepts, F[1,5] = 3.96, P
= 0.103). Subsequently, however, MEI increased in the control deer (F[2,40]
= 3.86, P = 0.029), except during 15-19 April (Fig.
1).
Temporal patterns of urinary A:C ratios differed significantly between restricted
and control deer (F[2,46] = 9.45,
P = 0.001) (Fig. 2), even though initially there
was no significant difference (H0:
equal intercepts, F[1,5] = 1.40,
P = 0.289) (Fig. 2). Urinary A:C ratios of control
deer increased slightly throughout the study (H0:
β1
= 0, T46 = 1.59, P = 0.119;
H0: β2
= 0, T46 = 1.76, P = 0.086),
whereas those of restricted deer exhibited a pronounced increase by 7 April
(H0: β1
= 0, T46 = 2.59, P = 0.013;
H0: β2
= 0, T46 = 3.98, P = 0.001).
There was no significant relation between recent MEI and urinary A:C ratio
(H0: β1
= 0, T43 = 0.21, r2
= 0.01, P = 0.839) of the seven deer (Fig. 3)
but there was a marginally significant curvilinear relation between A:C ratios
and progressive percent mass loss (H0:
β3
= 0, T41 = 1.63, r2
= 0.42, P = 0.110) (Fig. 4). Short-term severe
nutritional restriction (15-19 April) had no apparent or consistent effect
on the A:C ratios of the already restricted deer or the control deer (Table
1). The urinary A:C ratio was significantly related to the urinary UN:C
(H0: β1
= 0, T49 = 9.50, r2
= 0.59, P < 0.001) and 3-MeH:C ratios (H0:
β1
= 0, T49 = 5.65, r2
= 0.43, P < 0.001).
 |
| Fig. 1. Recent (2 days prior to urine
sampling) mean metabolizable energy intake (MEI) of captive adult white-tailed
deer (Odocoileus virginianus) fed either restricted (treatment)
or ad libitum (control) amounts of a low-protein, low-energy (LPLE)
commercial diet from 11 February to 5 May 1988 at Grand Rapids, Minnesota.
Prior to the study, all deer were maintained on a high-protein, high-energy
commercial diet, but consumption was not monitored prior to initiation
of the study. Sample sizes were four and three deer in the treatment
and control groups, respectively. |
|
| Fig. 2. Urinary allantoin:creatinine
ratios of captive adult white-tailed deer maintained on a high-protein,
high-energy commercial diet through 10 February 1988 and fed either
restricted (treatment) or ad libitum (control) amounts of a low-protein,
low-energy (LPLE) commercial diet from 11 February to 5 May 1988 at
Grand Rapids, Minnesota. Sample sizes were four and three deer in the
treatment and control groups, respectively. |
|
| Fig. 3. Urinary allantoin:creatinine
ratios versus recent (2 days prior to urine sampling) mean daily metabolizable
energy intake (MEI) of captive adult white-tailed deer fed restricted
(treatment) or ad libitum (control) amounts of a low-protein, low-energy
(LPLE) commercial diet from 11 February to 5 May 1988 at Grand Rapids,
Minnesota. Sample sizes were four and three deer in the treatment and
control groups, respectively. The thick vertical line demarcates the
winter maintenance requirement of captive white-tailed deer (561 kJ/kg0.75
body mass per day; Ullrey et al. 1970). |
|
| Fig. 4. Relationship of urinary allantoin:creatinine
ratios to cumulative body-mass loss in captive adult white-tailed deer
that consumed varying amounts of a low-protein, low-energy (LPLE) commercial
diet from 11 February to 5 May 1988 at Grand Rapids, Minnesota. Sample
sizes were four and three deer in the treatment and control groups,
respectively. |
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