Camp. Biochrm. Phrsiol. Vol. VA. No. I, pp. 51-56, 1984 Printed in Great Biitain

0300-9629/84 $3.00 + 0.00 $ 1984 Pergamon Press Ltd

COLONIC ABSORPTION AND SECRETION OF FLUIDS,

ELECTROLYTES AND ORGANIC ACIDS IN EAST AFRICAN WILD RUMINANTS

E. T. CLEMENS and G. M. 0. MALOIY

Department of Veterinary Physiology, University of Nairobi, Nairobi, Kenya, East Africa, and Department of Veterinary Science, Institute of Agriculture and Natural Resources, University of

Nebraska-Lincoln, Lincoln, NB 68583-0905, USA. Telephone : 402 472-2952

(Received 13 April 1983)

Abstract- 1. In sixteen species of wild ruminants colonic absorption of fluids averaged 489; of the fluids entering the large bowel. Values ranged from 26”/:, (steenbok) to 65% (gerenuk).

2. Absorption of sodium, potassium, chloride and organic acids were variable between species. 3. Colonic absorption of potassium ions were found to be related to diet selection and body weight of the

animals. 4. Colonic absorption of volatile fatty acids were significantly greater in browsers (28.4 mmol/l) than

grazers (9.6 mmol/l). 5. The African buffalo are the only species of wild ruminants not forming a faecal pellet ; colonic functions

were not different from those species forming faecal pellets.

INTRODUCTION

Studies of digestive physiology and metabolism of wild

ruminants are noticeably limited (Kay et al., 1980;

Hoppe et al., 1977a,b; Maloiy et al., 1982; Clemens and Maloiy, 1983 ; Clemens et al., 1983). Furthermore, the majority of these investigations are restricted to studies of reticula-rumen functions.

Prior studies of the caecum-colon of wild ruminants relate that: fermentive digestion continues within the large bowel ; lower bowel fermentation values appear related to both diet selection and to body weight; osmotic balance is maintained by the inorganic elec- trolytes and fermentative endproducts ; and conserv- ation of body fluids and faecal water loss are promin- ant functions of the colon (Skadhauge et al., 1980; Maloiy et al., 1982; Clemens and Maloiy, 1983; Clemens et al., 1983). Several questions remain un- answered including : the relationship of diet and body weight to the colonic absorptive process; the fluid, inorganic electrolyte, and fermentative endproduct inter-relationship in the absorptive process; and the relative performance of various colonic segments in the absorptive-secretory process. The present study ad- dresses these questions.

METHODS AND MATERIALS

Fifty-one adult, male animals representing 16 species of East African wild ruminants were used in the study. These include: five Kirk’s dik-dik (Madoqua kirki), two suni (Nesorraqus moschatus), three giraffe (Giraffe camelopard&), three gerenuk (Litocranius wal[eri), three eland (Taurotragus oryx), four Grant’s gazelle (Gazella yranri), two steenbok (Raphicerus campestris), four impala (Aepyceros melampus), four Thomson’s gazelle (Gazella thomsoni), three African buffalo (Buhalus ca$er), two waterbuck (K&us e&psi prymnus), three wildebeest (Connorhaetes taurinus), three hartebeest (Alcephalus husrlaphus), three topi (Damaliscus

lunatus), three mountain reedbuck (Reduncajuluorufula), and four oryx (Oryx gazella). All animals were collected from their natural habitat in conjunction with wildlife management programs. Field analyses and sample collection were begun immediately after sacrifice and generally completed within one hour after death of the animal. Methods of sample collection and laboratory analysis were reported earlier (Clemens and Maloiy, 1983).

Estimates of colonic absorption and secretion of fluids, electrolytes and organic acids were derived by the methods of Staaland (1975). Since organic acids, volatile fatty acids and lactic acid, may be produced and utilized in gut or its tissues, estimates of the colonic flux represent disappearance (absorp-

Table 1. Wild ruminant species categorized according to major feeding group, sub-feeding group and adult weight range*

1. Browsers a. Fruit and dicotyledon browsers

i. Krik’s Dik-Dik (5-6 kg) il. Suni (5-7 kg)

b. Tree and shrub browsers i. Giraffe (SO&750 kg)

ii. Gereouk (4&51 kg) II. Intermediate Feeders

a. Prefers browse i. Eland (40+650 kg)

ii. Grant’s gazelle (46-64 kg) iii. Steenbok (8-l I kg)

b. Prefers grasses i. Impala (53-71 kg)

ii. Thomson’s Gazelle (22-25 kg) III. Grazers

a. Fresh grass grazers i. African BulTalo (600-850 kg)

ii. Waterbuck (192-286 kg) iii. Wildebeest (171-242 kg)

b. Roughage grazers i. Hartebeest (116~160 kg)

ii. Mountain Reedbuck (23-28 kg) iii. Topi (I I I-147 kg)

c. Dry region grazers i. Oryx (168-209 kg)

*Classifications according to R. R. Hofmann (1973).

51

Table 2. Mean ( k SEM) values for apparent colonic absorption and secretion of fluids, electrolytes, and organic acids for sixteen species of wild ruminants*

Species and colonic Water Sodium segment

Kirk’s dik-dik Proximal colon

Distal colon

Suni Proximal colon

Distal colon

Giraffe Proximal colon

Distal colon

Gerenuk Proximal colon

Distal colon

Eland Proximal colon

Distal colon

Grant’s gazelle Proximal colon

Distal colon

Steenbok Proximal colon

Distal colon

Impala Proximal colon

Distal colon

Thomson’s gazelle Proximal colon

Distal colon

African buffalo Proximal colon

Distal colon

Waterbuck Proximal colon

Distal colon

Wildebeest Proximal colon

Distal colon

Hartebeest Proximal colon

Distal colon

Topi Proximal colon

Distal colon

Mountain reedbuck Proximal colon

Distal colon

Oryx Proximal colon

Distal colon

(ml/100 ml) (mg/lOO ml) -

-0.5 5.2 (6.1) (4.9) 42.1 23.8 (5.1) (0.3)

44.2 (4.6) 62.2

(22.6)

19.2 (8.8) 26.3

(15.6)

3.2 (21.8) 50.6

(10.5)

34.4 (39.6) 49.2

(34.2)

5.5 (6.1) 65.1

(14.9)

1.4 (1.8) 37.9

(16.0)

24.4 (3.8) 37.5 (3.2)

5.9 (3.8) 8.8

(4.2)

24.5 (1.3) 55.7 (5.3)

22.2 (5.8) 42.4 (8.9)

3.2 (1.4) 26.4 (2.1)

6.2 (4.4) 9.4 (0.4)

9.8 (7.8) 38.8 (8.4)

10.3 (7.4) 20.9 (4.6)

7.8 (13.1) 59.2 (5.0)

3.9 (6.4) 32.8 (7.2)

8.4 (0.6) 29.5 (8.7)

10.7 (12.6) 31.4 (7.0)

30.4 (7.0) 44.0 (8.7)

30.6 (9.7) 36.4 (7.0)

14.3 (23.0) 31.6 (1.9)

-0.1 (3.8)

- 5.8 (5.8)

22.6 (4.2) 66.4 (19.3)

8.1 (2.3) 28.2 (9.4)

20.5 (4.9) 57.3 (3.1)

14.9 (3.0) 31.4 (2.6)

17.8 (2.4) 56.4 (6.4)

9.5 (4.3) 19.9 (5.2)

11.3 (9.5) 38.0 (9.5)

20.4 (10.0) 42.4

(20.1)

Digesta component

Potassium Chloride (mg/lm ml) (mg/lm ml)

VFAs (mmol/l)

6.0 (4.9) 34.4 (8.2)

41.4 (21.0) 49.2

(33.2)

-2.3 (9.6) 31.4 (8.6)

-14.1 (10.3)

4.5 (10.5)

13.8 (3.4) 25.8

(10.7)

5.0 (1.2) 9.3

(0.5)

6.0 (7.8) 18.0 (5.0)

1.9 (1.5) 15.9 (6.4)

1.4 (1.0) 28.2 (3.9)

-5.6 (11.8)

1.8 (2.9)

-0.4 (1.4) 5.9

(2.9)

10.4 (10.7) 14.9 (6.4)

4.1 (0.8) 27.6

(11.2)

4.3 (1.4) 10.4 (2.3)

9.3 (2.8) 30.6 (4.2)

0.2 (2.5) 6.3

(5.6)

1.0

(0.6) 9.2

(1.3)

29.2 (16.1) 32.2

(18.6)

0.8 (1.0) 11.6 (1.8)

-7.6 (9.7) II.1 (2.6)

3.0 (0.1) 7.2

(1.2)

0.0 (0.0) 0.1

(0.0)

3.0 (3.3) 9.6

(2.4)

4.0 (1.3) 12.4 (2.9)

-1.8 (0.9) 16.6 (1.2)

-1.1 (11.1)

6.6 (0.4)

11.6 (0.8) 15.6 (0.4)

1.3 (5.0) 5.3

(2.3)

13.1 (2.7) 27.2 (4.3)

2.5 (0.1) 7.6

(4.3)

1.9 (2.8) 19.1 (2.5)

4.3 (2.3) 12.2 (1.9)

1.3 (2.6) 15.5 (3.2)

48.6 (40.2) 66.1

(54.5)

1.6 (3.4) 27.7

(14.4)

0.6 (2.6) 19.1

(22.2)

5.5 (1.4) 18.6 (2.0)

19.1 (4.1) 33.4 (4.4)

10.0 (5.8) 22.6 (7.8)

0.1 (1.5) 17.3 (8.7)

8.4 (2.8) 30.6 (3.0)

12.8 (19.0) 19.6 (1.0)

13.9 (0.2) 20.1 (1.0)

3.4 (6.5) 5.8

(4.3)

I.0 (0.1) 17.6 (9.9)

5.0 (0.8) 11.4 (2.7)

16.3 (4.6) 21.7 (0.4)

11.0 (3.8) 24.9 (4.2)

LA (mmol/l)

0.2 (0.1) 0.1

(0.3)

0.4 (0.4) 0.4 (0.4)

-0.2 (0.4) 0.2 (0.2)

- 2.2 (0.3) 0.1

(0.3)

0.1 (0.1) 0.1

(0.1)

0.9 (0.8) 1.5

(1.2)

-0.8 (0.4)

-0.6 (0.2)

0.1 (0.1)

-0.6 (0.5)

-0.9 (0.4) 0.5

(0.3)

0.0 (0.1)

-0.1 (0.0)

0.1 (0.1) 0.0

(0.0)

0.1 (0.1) 0.1

(0.1)

0.1 (0.1) 0.3

(0.2)

0.1 (0.0 0.2

(0.1)

0.2 (0.2) 0.2

(0.2)

-0.1 (0.1)

-0.3 (0.2)

*Positive values represent net absorption (disappearance), negative values represent net secretion (appearance)

52

Colonic functions of wild ruminants 53

tion plus utilization) and appearance (secretion plus produc- tion) of these acids. Body weights and food preferences ofeach species were taken as those reported by Hofmann (1973) (Table 1).

Data were subject to analysis of variance, Duncans Multiple Range test, and regression analysis for determi- nation of significant differences (Steel and Torrie, 1960).

RESULTS

The net absorption-secretion of fluids and elec- trolytes, and the net appearance and disappearance of organic acids within the proximal and distal colon are presented in Tables 24. Approximately 15% of the

fluids entering the large bowel were absorbed in the proximal colon, while an average of 4550% were absorbed within or before the distal colonic measure- ment. Values ranged from a low of 26% (steenbok) to 65% (gerenuk). When considering the major feeding groups (Table 3), browsers had somewhat greater fluid absorption values than did intermediate feeders and grazers. However, these effects were not significantly different and were primarily due to the greater fluid absorption values observed for the gerenuk. There were no measurable relationship between fluid absorp- tion and body weight of the animal (Table 4).

The movement of sodium, potassium and chloride ions were variable between species. Sodium flux values

Table 3. Mean ( k SEM) values for apparent colonic absorption and secretion of Ruids, electrolytes. and organic acids for the

major and sub-feeding groups of wild ruminants*

Food selection

Major groups

Browsers

Proximal colon

Distal colon

Intermedtate

Proximal colon

Distal colon

Grazers

Proximal colon

Distal colon

Sub groups

Fruit and dicotyledon

Proximal colon

Distal colon

Trees and shrub

Proximal colon

Distal colon

Prefers browse

Proximal colon

Distal colon

Prefers grass

Proximal colon

Distal colon

Fresh grass

Proximal colon

Distal colon

Roughage

Proximal colon

Distal colon

Dry region

Proximal colon

Distal colon

Water

(ml/l00 ml)

Sodium

(mgil00 ml)

13.8 13.5

(9.5) (7.6) 51.2 30.8

(5.8) (7.3)

14.0

(4.1) 46.4

(3.9)

10.6

(3.2) 26.3

(4.3)

16.4

(4.4) 44.5

(3.6)

13.6

(3.3) 26. I

(5.8)

18.0

(12.7)

47.9

(7.1)

9.2

(4.6) 24.5

(6.0)

4.0

(12.6)

58.8

(10.2)

23.4

(25.4)

45.5

(20.1)

19.2

(3.6) 43.8

(5.4)

14.1

(4.2) 25.7

(7.6)

8.8

(7.1) 49.0

(6.0)

7. I

(4.7) 26.9

(4.6)

17.2

(9.5) 34.5

(3.2)

I I.7

(6.4) 16.9

(9.2)

19.6

(2.2) 58.2

(3.0)

11.6

(2.3) 26.0

(3.1)

II.3

(9.5) 38.0

(9.5)

20.4

( 10.0) 42.4

(20.1)

Potassium

(mg,‘lOO ml)

Digesta component

Chloride

(mg;lCKl ml)

9.4

(7.0) 33.8”

(7.5)

4.6

(1.4) 18.8b

(2.7)

3.6

(3.3) 13.lb

(3.2)

16.1

(8.7) 38.6

(9.6)

-6.2

(6.7) 22.5

(10.2)

7.4

(2.2) 15.6

0.4)

1.7

(0.8) 22.0

(4.2)

2.7

(6.8) 8.6

(5.4)

6.4

(1.6) 21.5

(4.4)

0.2

(2.5) 6.3

(5.6)

5.7

(4.7) 14.5

(4.1)

I.3

(0.8) 9.3

(1.8)

3.8

(1.6) 12.0

(1.8)

9.0

(6.3) 15.8

(5.9)

-2.0

(2.9) I I.5

(1.1)

I.5

(0.8) 4.2

(1.7)

I.1

(1.3) 14.5

(1.6)

3.6

(3.7) 8.6

(2.6)

3.8

(1.9) 15.3

(3.5)

4.3

(2.3) 12.2

(1.9)

VFAs

(mmol/l)

10.8

(8.8) 28.4”

(1.7)

8.8

(2.2) 25.5ah

(3.0)

9.6

(2.4) I7.4b

(2.6)

14.8

(12.5)

30.0

(15.3)

1.3

(2.0) 24.8

(8.8)

13.4

(3.1) 27.0

(3.5)

4.2

(2.0 23.9

(5.0)

9.1

(5.2) 13.8

(5.5)

9.3

(3.1) 16.7

(2.2)

11.0

(3.8) 24.9

(4.2)

LA

(mmol/l)

-0.1

(0.3) 0.2

(0.2)

-0.1

(0.3) 0.3

(0.4)

0.1

(0.1) 0.0

(0.1)

0.3

(0.0 0.2

(0.2)

-0.8

(0.7) 0.1

(0.1)

0.4

(0.3) 0.6

(0.6)

-0.4

(0.3) -0.1

(0.3)

0.1

(0.1) 0.0

(0.1)

0. I

(0.1) 0.2

(0. I )

-0.1

(0.1) -0.3

(0.2)

Value within the distal colon with unlike superscripts are significantly different (P c 0.05).

*Positive values represent net absorption (disappearance); negative values represent net secretion (appearance).

54 E. T. CLEMENS and G. M. 0. MALOIY

Table 4. Mea” (+SEM) values for apparent colonic absorption and secreGon of fluids, eleclrolytes, and organic acids for

seven weight groups of wild ruminants*

Weight group

Less than 20 kg

Proximal colon

Distal colon

20 lo 50 kg

Proximal colon

Dislal colon

51 ,o 100 kg

Proximal colon

Distal colon

101 lo 150 kg

Proximal colon

Distal colon

151 to2OOkg

Proximal colon

Distal colon

201 lo 300 kg

Proximal colon

Distal colon

More than 300 kg

Proximal colon

Distal colon

Waler

(ml’100 ml)

Sodium

(mg;lOO ml)

14.7 8.5

(9.9) (3.6) 43.1 21.2

(6.3) (5. I)

I I.2

(64) 60. I (3.8)

5.7

(3.4)

28.6

(4.6)

17.2

(5 6) 47.2

(5.61

16.2

(4.9) 31.6

(6.2)

‘0.5

(4.9) 57.3

(3 I)

14.9

(3.0)

31.4

(2.6)

12.1

(9.1) 43.7

(9.3)

20.8

(I 3.4)

36.5

(4.2)

I2.0

(7.0) 39.2

(4.X)

17.9

(8.1) 39.5

(I 5.8)

12.2

(8.4) Il.0

(I I .O)

17.0

(12.1)

29.8

(12.3)

Potassium

(mg;lCO ml)

13.8

(6.9) 34.0t

(8.Q

2.4

(2.9) 26. I (4.6)

3.4

0.1) 12.6

(3.2)

4.3

(I .4) 10.4

(2.3)

0.9

(?.I)

10.6

(6.1)

6.1

(6.4) II.3

(4.2)

2.0

(7.2) 20.0

(8.4)

Chloride

(mg;lGG ml)

7.7

(4.9) 14.4

(4.6)

~ 1.2

(1 5) 16.9

(1.4)

2.0

(I .O) 6.2

(2.7)

2.5

(0. I ) 7.6

(4.3)

6.0

(2.5)

15.2

(3.4)

55

(3.7) 9.5

12.8)

0.9

(3.0) 8.5

(2.2)

VFAs

(mmol;l)

13.8

(9.6) 28.3

(1 1.8)

10.4

(2.8)

25.8

(2.3)

9.6

(4.1) 25.3

(5.4)

5.0

(0.8) II.4

(2.7)

9.0

(3.5) 23.4

(3.6)

7.6

(4.4) 11.5

(4.2)

6.6

(5.4) 22.0

(6.7)

LA

(mmol’l)

0.0

(0.2)

0.1

(0.2)

~0.6

(0.4) 0.4

(0.2)

0.5

(0.4) 0.5

(0 7)

0. I

(0. I) 0.2

(0. I)

0.1

(0. I) -0.2

(0.3)

0. I

(0.0) 0. I

(0.1)

- 0.4

(0. I) 0. I

(0.1)

*Positive values represent net absorption (disappearance). negative values represent net secretion (appearance).

tSlg”ilican( regression analysis (P < 0.02) for reduced potassium absorplion (distal colon) relative to increased body weight.

ranged from a net colonic secretion in the wildebeest (- 5.8 mg/lOO ml) to 49 mg absorption/100 ml observed in the giraffe. Potassium values were also variable among species (low of 1.8 mg/lOO ml in the African buffalo to a high of 49.2 g/100 ml in the suni). Chloride values were the least variable among species and, with the exception of the suni, were within the range of O-1 5 mg/lOO ml. Of the three electrolytes only potassium showed a significant relationship with the animals’ dietary habits (browsers having the greater potassium absorption, 34 mg/lOO ml, and grazers the least, 13.1 mg/lOO ml). Potassium absorption was also found to be related to the animals body weight, with the lighter animals having the higher absorption.

Volatile fatty acid (VFA) values were equally as variable among species as were the inorganic elec- trolytes. Distal colonic VFA disappearance values ranged from 5.8 mmol/l (wildebeest) to 66.1 mmol/l (suni). VFA disappearance values were significantly related to diet selection (Table 3). As with the pot- assium ions, net VFA disappearance was greatest in browsers (28.4 mmol/l) and least in grazers (17.4 mmol/l). Lactic acid values of the colonic contents were generally too low for significant measurements.

DISCUSSION

The mammalian large intestine and rectum have been characterized as the “digestive organs for salt

and water conservation” (Skadhauge et al., 1980). Fermentative digestion has also been indicated as a prominent feature of the large bowel (Alexander, 1965 ; Clemens, 1979; Stevens et al., 1980). Although, in ruminants, colonic bacterial fermentation contri- bution to fiber digestion is believed limited (Goodall and Kay, 1965 ; Hoover, 1978 ; Skadhauge et al., 1980), organic acids are a principle component of the in- testinal contents (Maloiy and Clemens, 1980a).

Skadhauge and co-workers (1980) have shown that the amount of dry matter digested within the large bowel of the small ruminant (i.e. dik-dik antelope) is minimal, and that, compared to inert markers, dry matter content is an acceptable tool for calculating fractional absorption rates of fluids and electrolytes. A detailed description of this technique using dry matter as the colonic marker was presented by Staaland ( 1975).

When considering the large bowel, several investi- gators have shown prominent differences in the co- ionic electrolyte flux between the proximal and distal regions (Stevens et al., 1980; Skadhauge et a[., 1980; Maloiy and Clemens, 1980b). Within the present group of wild ruminants the spiral colon generally comprised the proximal half and had a fluid to pasty consistency (dry matter range 1 l-24%). Caecal con- tents were somewhat more fluid with a dry matter averaging 16% (Clemens and Maloiy, 1983). For these animals the distal colon represents the region of faecal

Colonic functions of wild ruminants 55

pellet formation, for all species except the African buffalo. Dry matter consistency within this segment of tract ranged from 23 to 65x, with a mean value of 34%. The African buffalo which does not form a faecal pellet had a mean distal colonic dry matter of 15%.

Stevens and co-workers (1980) described two co- ionic epithelial transport systems. The first system is sodium dependent in which sodium and VFAs are absorbed at similar rates. This results in the increased movement of fluids from the gut. The sodium-driven fluid recovery system is characteristic of that seen in the distal colon of the pony, colon ofthe dog and colon of the goat (Stevens et al., 1980). The second system is one in which VFAs are absorbed more readily than sodium ions. In this system VFAs are absorbed in pre- dominantely the undissociated form, resulting in less water absorption from the gut. Such a system is characteristic of that seen in the reticula-rumen, proximal colon of the pony and colon of the pig. The system allows for the accumulation of fluids and bicarbonates, for bacterial proliferation and for the removal of fermentative endproducts (VFAs). The present study would suggest that East African wild ruminants possess colonic transport systems favorable for fluid recovery within both the proximal and distal colon, and less favorable for fermentative digestion, as evident by the sodium : VFA absorption ratio. The one exception to these findings is the values observed for the suni. In this instance VFAs were absorbed several times more readily than sodium ions. However, pot- assium absorption is elevated in the suni, relative to other species of wild ruminants, and appears to be the driving force for VFA and water transport.

While the data would suggest that colonic con- ditions are not highly favorable for fermentative digestion, such actions are occurring within the large bowel of the wild ruminant (Maloiy et al., 1982). VFA formation and removal was an important part of the colonic functions.

The significant values observed for diet selection, potassium absorption and VFA disappearance is in part explainable from the data presented in an earlier publication (Clemens and Maloiy, 1983). In that study, browsers were observed to consume more potassium (reticula-rumen contents, 99.8 m-equiv/l) than either intermediate feeders (69.9 m-equiv/l) or grazers (42.4 m-equiv/l). The relationship was carried on through the caecal and colonic contents of these animals. Thus, more potassium was available for absorption, possibly accounting for the significant findings. Similarly, co- ionic VFA concentrations were greater in browsers and intermediate feeders than those observed for grazers (Clemens and Maloiy, 1983).

The one species which may have been expected to, but did not show, a marked difference in colonic functions was the African buffalo. This animal was the only member of the wild ruminants which did not form a faecal pellet. As such it might have been expected that colonic transport systems would favor those retaining fluids within the gut, as was observed for Zebu cattle (Maloiy and Clemens, 1980b). While smaller quantities of fluids were absorbed from the colon of the African buffalo, relative to most other species, the values were not significantly different from several species forming faecal pellets (most notably the wildebeest and steen- bok). Again, potassium absorption from the colon of

the African buffalo was considerably lower than most other species of wild ruminants and may be the driving force for the reduction in fluid absorption seen in these animals.

Acknowledgements-We are most grateful to Mr D. Sindiyo, Director, Department of Wildlife Conservation and Management, for permits and assistance in obtaining re- search specimens, and to Drs V. Langman and P. Hoppe for their assistance in the field work. The competent technical assistance both in the field and laboratory from Mr J. Nturibi, J. Gatihi, S. Mungai and S. Ojwang Orwa is most gratefully appreciated.

The study was supported by research grants from the University of Nairobi, Dean’s Committee for Research Funds, and from the Leverhulme Trust, London, England. Published with the approval of the Director, Nebraska Agricultural Experiment Station, Paper No. 7151, Journal Series.

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