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Digestibility of a high-fiber biscuit-based diet by black and white colobus (Colobus guereza).

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American Journal of Primatology 9: 137-144 (1985)
Digestibility of a High-Fiber Biscuit-Based Diet by Black and
White Colobus (Colobus guereza)
B.E. WATKINS,’ D.E. ULLREY,2AND P.A. WHE’ITER2
‘Chicago Zoological Park, Brookfield, Illinois and ‘Department of Animal Science,
Michigan State University, East Lansing, Michigan
The acceptability and digestibility of a high-fiber biscuit-based diet was
investigated using two adult male Colobus guereza animals. Although the
animals were initially reluctant to accept the biscuit, it was eventually
readily consumed. Apparent digestion coefficients for the diet (average composition, dry matter basis: 16% crude protein, 25% neutral detergent fiber
(NDF), 9.5% acid detergent fiber (ADF), 1.2% acid lignin) determined by
total fecal collection were 0.871 for dry matter, 0.813 for NDF, 0.693 for
ADF, and 0.208 for acid lignin. Fiber digestive capabilities in C. guereza
generally exceeded those reported in ruminant species based on predictive
equations. Use of acid lignin and Crz03 as markers underestimated dry
matter digestibility by 3.9 and 6.0%, respectively.
Key words: Colobus guereza, digestibility, fiber, pregastric fermentation, black and
white colobus, guereza
INTRODUCTION
It is well recognized that pregastric fermentation similar to that in ruminants
occurs in leaf-eating monkeys belonging to the subfamily Colobinae [Kuhn, 1964;
Bauchop & Martucci, 1968; Bauchop, 19781. The need for dietary fiber to maintain
proper gastrointestinal function in these species, as demonstrated in ruminants, and
the extent of fiber digestion have not been well established, however. Field studies
indicate diets of Colobus guereza in eastern and western Africa typically contain
greater than 50% leaf materials [Oates, 1977; Struhsaker, 1978; Gautier-Hion, 19831.
Based on reported leaf composition from equatorial Africa [Hladik, 1978; McKey et
al, 1981; Waterman & Choo, 1981; Baranga, 1982, 19831, it is reasonable to assume
that diets of this species in the wild would often contain over 30% neutral detergent
fiber (NDF) and 10% acid detergent fiber (ADF) even when primarily young leaves
relatively low in fiber are being selected. In captivity, colobines are often fed diets
similar to those fed to primate species that are not primarily folivorous andor do
not have pregastric fermentation. These diets are typically based on commercial
Received February 13,1985;revision accepted May 14,1985.
Address reprint requests to Bruce E. Watkins, Chicago Zoological Park, BrooMield, IL 60513.
0 1985 Alan R. Liss, Inc.
138 I Watkins, Ullrey, and Whetter
primate biscuits containing a low concentration of fiber (ie, 2-5% crude fiber, 1019% NDF, and 5-7.5% ADF dry matter basis). Currently there is no commercial
high-fiber product available for feeding leaf-eating monkeys in captivity. The high
incidence of gastrointestinal disorders reported in captive colobines [Hill, 19641
indicates the importance of proper dietary management in these species.
This study was conducted with black and white colobus monkeys (guerezas) to
(1)evaluate the acceptability of a high-fiber biscuit formulated by one of the authors
(Ullrey); (2) determine the digestibility of fiber and other nutrient fractions; (3)
compare fiber digestibility in the colobus with predicted digestibility in ruminant
species; and (4) evaluate the use of internal (acid lignin) and external (Cr203)
markers for estimating digestibility.
METHODS
Two male C. guereza animals (“Billy”-6 years, 8.68 kg; “Ditto”-3 years, 7.26
kg) were housed individually in 1.2-long x 0.8 wide x 1.4 high (meters) stainlesssteel metabolism cages kept indoors. Weighed amounts of food were offered once
daily to each animal. Foods remaining the following day were collected and weighed
before cage cleaning and refeeding. Water was available as a free choice. During the
adjustment period, a high-fiber biscuit (Table I) was offered ad libitum to each
monkey while a commercial biscuit and a canned primate product the animals were
accustomed to receiving were gradually withdrawn. Fruits and vegetables were
chopped into pieces not exceeding 25 mm in thickness and offered daily in constant
amounts which, in combination, accounted for approximately 50% of the calculated
TABLE I. Composition of the High-Fiber Biscuit
Item
Corn
Soybean meal (48%CP)
Alfalfa meal, dehyd (17% CP)
Sugar beet pulp
Wheat standard middlings
Soybean hulls
Sucrose
Calcium carbonate (38% Ca)
Dicalcium phosphate (21%Ca, 18%P)
Salt
Chromic oxide (CrzO3)
Trace mineral premixa
Vitamin premixb
Soybean oil (preserved with ethoxyquinIc
Total
Calculated composition
Crude protein (%)
Crude fiber (%)
Calcium (%)
Phosphorus (%)
Percentage
30.8
40.1
3.0
5 .O
5.0
7.0
2.0
0.7
1.6
0.5
0.3
0.5
0.5
3.0
100.0
24.8
6.6
0.81
0.65
aProvided in diet (mgkg): iron, 100; copper, 5; zinc, 75; manganese, 50; cobalt,
1;iodine, 1;selenium, 0.2.
bProvided in diet (per kg): vitamin A, 10,000 IU; vitamin DB,1,000 I U
vitamin E, 100 IU; menadione sodium bisulfite, 4 mg; thiamin, 5 mg;
riboflavin, 10 mg; panthothenic acid, 20 mg; niacin, 40 mg; vitamin Bg, 4 mg;
biotin, 0.2 mg; folic acid, 0.5 mg; vitamin Biz, 30 pg; choline, 800 mg.
‘Applied after extrusion and dusted with ethyl-cellulose-coated vitamin C t o
provide 500 m g k g diet.
Digestibility by Colobus I 139
dry matter intake. Six days after the high-fiber biscuit had entirely replaced the
commercial products, a constant amount of high-fiber biscuits was offered daily for
nine days during pretrial and collection periods. To minimize orts and intake variability, the total amount of dry matter offered during these periods was slightly less
(approximately 5%) than the average ad libitum dry matter intake established
during the adjustment period. During the last five days of the experiment (collection
period), all feces were removed from the cages twice daily using a flexible-bladed
putty knife, placed in plastic containers, and frozen. A representative sample (approximately 50 g) of each food item was retained daily during the pretrial and
collection periods, placed in a plastic bag, and frozen. Similarly, all foods remaining
from the previous day were collected, separated, placed in individual bags, and
frozen.
All food samples and feces were freeze-dried with the exception of the grapes
and tomato. It was necessary to dry these items in a vacuum oven a t 40°C to prevent
a sugar glaze from separating from the remainder of the sample. All samples were
ground in a Wiley mill before analysis. Proximate analyses were carried out on
pooled food samples and daily fecal samples using AOAC [1980] procedures. Crude
protein was calculated as Kjeldahl nitrogen x 6.25; dry matter was determined by
drying samples at 60°C in a vacuum oven; fat (ether extract) was determined by
diethyl ether extraction in a Goldfkch apparatus; ash was represented by the
residual remaining after igniting samples at 600°C. NDF, ADF, and 72% sulfuric
acid lignin were determined after Goering and Van Soest [1970], with the exception
of omitting sodium sulfite from the NDF procedure. Gross energy was analyzed
using adiabatic oxygen bomb calorimetry. Metabolic fecal nitrogen was estimated
as the difference between total fecal nitrogen and the nitrogen content of the fecal
NDF [Van Soest, 19821.
RESULTS
The high-fiber biscuit was not accepted by either animal until the amounts of
commercial products offered had been substantially reduced. However, once consumption began, the monkeys appeared to rapidly develop a taste for the new biscuit.
By the end of the adjustment period, high-fiber biscuits were readily consumed.
Intake during the pretrial and collection periods was relatively constant with
the high-fiber biscuit making up approximately 54% of the dry matter intake of both
animals (Table 11).The high-fiber biscuit was the primary source of protein and fiber
TABLE 11. Average Daily Consumption (Dry Matter Basis) and Percent of Daily Dry
Matter Intake of Each Diet Component During Pretrial and Collection Periods
Amountldav (a)
High fiber biscuit
Grapes
Apple
Orange
Lettuce
Sweet potato
Tomato
Pear
Total
-
-
Billy
Ditto
X percent
89.6 f Oa(0)b
14.7 f 0.5 (0)
20.5 +_ 0.5 (6)
5.3 0 (0)
1.7 O(0)
23.9 0.1 (6)
3.0 t O ( 0 )
5.5 +_ 0 (0)
164.2 f 0.6 (7)
81.2 f 0.4 (3)
13.6 f 0.5 (0)
19.9 O(0)
4.5 f 0.4 (1)
1.6 k 0 (0)
23.2 f O(0)
2.8 f 0 (0)
5.0 & O(0)
151.8 k 0.5 (4)
54.2 f 0.2
8.9 f 0.2
12.8 0.1
3.1 k 0.1
1.0 0
14.9 k 0
1.8 +_ 0
3.3 0
100
**
*
*
*
*
*
+ SE.
bNo. of days during eight-day pretrial and collection periods that each food was not totally consumed.
140 I Watkins, Ullrey, and Whetter
TABLE 111. Composition of Foods as Analyzed Used in Colobus Digestion Trials (Dry
Matter Basis)
High-fiber biscuit
Thompson
seedless grape
Emperor grape
Apple
Orange
Lettuce
Sweet potato
Tomato
Pear
Dry
matter
Crude
protein
94.3
19.8
25.3
3.1
16.0
14.4
17.7
4.8
23.9
5.5
15.6
3.3
2.0
Percentage
Gross
Ash energy'
NDF
ADF
Acid
lignin
3.3
2.2
6.8
1.6
3.94
3.43
34.4
2.7
11.50
2.2
0.97
0.66
7.0
11.3
4.5
11.4
2.4
8.2
9.6
2.1
1.4
2.5
9.3
3.6
7.9
1.8
3.47
3.60
3.66
3.26
3.70
3.62
3.71
9.9
11.1
10.4
14.1
21.8
17.2
19.1
7.5
7.7
10.6
13.0
4.6
18.0
13.4
5.78
1.50
0.67
1.89
0.51
3.07
3.58
Ether
extract
5.4
15.6
6.4
17.6
3.5
akcal/g.
TABLE IV. Average Daily Nutrient Intake and Mean Composition of the Diet as Consumed
(Dry Matter Basis) During Pretrial and Collection Periods
Amount/day (g)
Billy
Dry matter
Crude protein
Ether extract
Ash
Gross energy (kcal)
Neutral detergent fiber
Acid detergent fiber
Acid lignin
-
164.2
26.3
7.6
8.1
621.9
41.4
15.6
2.0
f 0.6"
f0
f 0.1
k0
k 2.2
+ 0.2
f 0.1
f 0.1
-
Ditto
X percent
151.8 f 0.5
24.0 k 0.1
7.1 f 0.1
7.4 k 0.1
574.5 1.9
38.0 f 0.2
14.3 f 0.1
1.9 f 0.1
28.47
15.94
4.65
4.91
3.79b
25.13
9.47
1.22
*
i SE.
bkcal/g.
in the diet (Table IID. The total diet consumed averaged 16% crude protein, 25%
NDF, and 9.5%ADF on a dry basis (Table IV).
Apparent digestibility of all fractions was similar for both animals (Table V).
Non-NDF nitrogen accounted for 78.0 0.7% and 82.6 0.4% of total fecal nitrogen
in Billy and Ditto respectively. The use of acid lignin and chromium as internal
markers underestimated average dry matter digestibility by 3.9% and 6.0%
respectively.
DISCUSSION
Initial reluctance of the guerezas to accept the high-fiber biscuit was not unexpected. Captive primates accustomed to a relatively constant diet often will not
accept novel foods immediately. Once the monkeys were forced to change their
dietary habits by reduction of the quantities of commercial products offered, the new
biscuit was readily accepted and usually consumed before the fruits and vegetables
were finished.
Digestibility by Colobus / 141
TABLE V. Apparent Digestibility as Determined by Total Collection, Acid Lignin Indicator
Method, and Cr203Indicator Method (N = 2)
Dry
matter
Percentage
Gross
Ash
energy
Crude
protein
Ether
extract
78.16
1.95
83.97
1.03
55.92
1.11
83.68
0.24
72.46
2.31
79.82
1.13
81.81
0.46
69.33
2.25
77.52
1.02
NDF
ADF
Lignin
85.49
0.47
81.27
0.98
69.33
0.50
20.81
0.37
44.41
1.82
81.72
0.73
76.38
1.37
61.31
0.88
0
0
37.71
2.36
79.61
1.02
73.66
1.81
57.33
1.89
-11.41
1.18
Cr
Total collection
x
87.06
0.12
f SE
Acid lignin
x
f SE
28.80
1.14
10.25
0.95
Cr203
x
f SE
0
0
Apparent dry matter digestibility of the diet was high and exceeded most values
reported for ruminants consuming high-quality forage and concentrate diets. High
apparent dry matter digestibility (81-90%) has also been reported in five other
species of colobinae fed diets containing 15-22% NDF and 8-11% ADF, dry basis
[Ullrey et al, 19821. Apparent crude protein digestibility may have been low relative
to dry matter digestibility because of metabolic fecal nitrogen excretion. Ullrey et a1
[ 19821 also reported apparent crude protein digestibility (62-78%) to be low relative
to dry matter digestibility in five other colobines. True protein digestibilities estimated by subtracting non-NDF fecal nitrogen from total fecal nitrogen were 95.6%
and 95.8% for Billy and Ditto respectively. Milton et a1 [1980] similarly found fecal
nitrogen in the howler monkey, a hindgut fermentor, to be primarily of metabolic
origin. Gross energy digestibility was only slightly lower than dry matter
digestibility.
The high digestibilities of the NDF and ADF fractions indicate that the guereza
has a n impressive ability to digest pectin, hemicellulose, and cellulose. Based on
acid lignin content of the ADF, guerezas in the present study and in the study
reported by Oftedal et a1 [1982] were more efficient at digesting NDF and ADF
fractions than predicted based on models for wild and domestic ruminants (Figs. 1,
2). Similarly, NDF digestibility in the guereza exceeded that reported for most
ruminant and nonruminant herbivores based on the 1ignidNDF ratio of the diets
[Parra, 1978; Van Soest, 19821. Higher fiber digestibility in the guerezas than
predicted in ruminants might relate to the nature of the diets fed in this study and
the study of Oftedal et a1 [1982]. The guerezas’ diets were generally lower in lignin,
NDF, and ADF than the diets used to develop the ruminant prediction equations.
Fiber digestion coefficients are typically higher on low-fiber diets than high-fiber
diets even though IignirdADF ratios might be similar [Van Seost, 19821. In addition,
the distribution of lignin in the foods offered to the guerezas probably differed from
that in the forages used for the ruminants. In the fruits and vegetables offered the
guereza, lignin would be expected to be primarily concentrated in grape and tomato
seeds and in apple and pear cores and therefore should not reduce the digestibility
of cellulose and hemicellulose not associated with these structures. Lignin is likely
to be widely distributed in the cell walls of most forages and thus to exert a general
depressive effect on the digestibility of a higher percentage of the hemicellulose and
-. -.
e
Domestic ruminants
C. guereza (present study)
C. guereza (Oftedal et al.
(1982 1
10
20
30
40
50
LlCNlN CONTENT OF ACID DETERGENT FIBER ( % 1
1
LJ
n
.
$j 10
0
2
I
10
20
30
40
50
LlGNlN CONTENT OF ACID DETERCENT FIBER ( % I
Fig. 1. Neutral detergent fiber digestibility in C. guerezu and ruminants as a function of the percentage
of lignin in the acid detergent fiber. (Ruminant data from Mould & Robbins, [1982] and Goering & Van
Soest [1970].ADF values for elk and white-tailed deer were determined by sequential analysis).
Fig. 2. Acid detergent fiber digestibility in C. guereza and ruminants as a function of the percentage of
the lignin in the ADF. (Ruminant data from Mould & Robbins [1982]. ADF values for elk and white-tailed
deer were determined using sequential analysis).
Digestibility by Colobus I 143
cellulose. Conversely, grinding and pelleting of diets generally decreases fiber digestibility by increasing passage rate [Van Soest, 19821. Presumably, the ground ingredients in the extruded biscuit, the primary source of fiber in this study, would have
reduced fiber digestibility.
The relatively high apparent lignin digestibility by guereza found in our study
and by Oftedal et a1 [1982] could have resulted from the chemical nature of the
lignin or from methodological problems [Van Soest, 19821. If artifact lignin was
being measured, actual 1ignidADF ratios may have been less than values used to
predict NDF and ADF digestibilities. Although acid lignin is generally considered
to be indigestible by mammals and their microflora, low lignin diets often have high
apparent lignin digestibilities [Van Soest, 19821.
Fiber digestive capacity in the guereza is particularly impressive in relation to
its small size. Particulate passage rate in ruminants is generally inversely related
to body size [Parra, 1978; Foose, 19821. Consequently,fiber digestibilities are generally considered to be lower in smaller ruminants than in large species, although as
diet quality improves the influence of body size becomes obscured [Van Soest, 19821.
Retention of fiber in small mammals might be longer than expected if a lower
metabolic rate reduces the constraint of minimum energy extraction rate. Miller et
a1 [1983] reported the BMR of the guereza to be 15% lower than the predicted
eutherian value. Field observations indicate the guereza may minimize energy
expenditure by sunbathing in the morning and being relatively inactive [Oates,
19771. Although no experimental data are available, the low metabolic rate and
high fiber digestibility exhibited by the guereza suggest food passage rate is relatively slow in this species.
Daily dry matter intake expressed as a percentage of body weight was slightly
higher in the present study than reported in guereza fed free-choice by Oftedal et a1
[1982] (1.99%versus 1.8%).The higher intake could be related to the higher cell wall
content of the diet consumed in our study (25% versus 16%). Digestible energy
intake per kg metbolic weight was slightly lower in the present study (108 versus
117 k~al/BW.~~kdday).
Even though the diet in o u r study was offered at slightly
less than previous ad libitum consumption, small amounts of food were often left
over.
Acid lignin and Cr2.203 proved to be unsatisfactory for estimating apparent
digestibility by the indicator method without correction for recovery. Van Soest
[ 19821suggested acid lignin should not be used as an internal marker if it makes up
less than 6% of the diet dry matter because the relative error of lignin determination
is inversely related to the lignin concentration. The reason for the poor recovery of
Cr203 in the feces is not known.
Conducting further digestibility trials using a wide range of fiber levels in
concert with food intake and food passage rate measurements could improve captive
management of the guereza and help our understanding of the guereza’s requirements in the wild. Long-term feeding trials will be necessary to establish whether a
high-fiber biscuit can reduce morbidity and enhance reproductive success in captive
guerezas and other leaf-eating monkeys.
CONCLUSIONS
1. Although not accepted immediately, the guerezas eventually readily consumed the high-fiber biscuit.
2. High digestion coefficients for NDF and ADF fractions indicate the guereza
has an impressive ability to digest fiber.
3. Based on acid lignin content of the ADF, guerezas were more efficient at
144 / Watkins, Ullrey, and Whetter
digesting NDF and ADF fractions than predicted based on available models for wild
and domestic ruminants.
4. Acid lignin and Crz03 did not prove to be satisfactory for estimating digestibility unless corrections were made for recovery.
ACKNOWLEDGMENTS
We wish to thank Mike Gierhahn, Patrick Stout, and Richard Spevak for their
assistance in the digestibility trials, and Rudolph Kormunda for preparing the
figures. This is Michigan Agricultural Experiment Station Journal Article No.
11334.This work was supported
in part by National Museum Act Grant No. FC-207280.
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