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The value of coffee pulp alone and in combination with other feeds in sheep nutrition in Ethiopia - Valeur de la pulpe de café, seule ou associée a d'autres aliments, dans l'alimentation des ovins en Ethiopie

Solomon Demeke

Department of Animal Science
Jimma Junior College of Agriculture
P.O. Box 347
Jimma
Ethiopia


Summary
Resume
Introduction
Materials and methods
Results and discussion
Acknowledgements
References


Summary

Two experiments were conducted with yearling rams to evaluate the nutritive value of coffee pulp ensiled on its own and ensiled in combination with either sugarcane stem, sugarcane top or elephant grass (Pennisetum purpureum). Quality and percentage nutrient composition of the silage, and voluntary feed intake, weight gain and protein digestibility by sheep were used as parameters of nutritive value. Good quality silage was produced from coffee pulp alone and in combination with the forages. Percentage composition of lignin, lignified protein and caffeine were highest in pure pulp silage and decreased, as a result of dilution by forages, in the others. Feed intake was low and all animals lost weight on all silages. In Experiment 1 the sheep regained initial body weight after 15 days of grazing at the end of the trial. In Experiment 2 initial body weight was regained at the ninth week of feeding, when gains were 75 g/d to 154 g/d.

Resume

Pour évaluer la valeur nutritive de la pulpe de café ensilée pure et associée avec des bouts blancs de canne à sucre, des tiges de canne et de l'herbe à éléphants (Pennisetum purpureum), 2 essais furent mis en place sur des antenais. Les paramètres suivants furent mesurés: valeur nutritive de l'ensilage exprimée en qualité et en pourcentage, l'ingestion volontaire, gain de poids et digestibilité des protéines. L'ensilage produit dans les différents cas était de bonne qualité. Les proportions de lignine, des protéines liées et de caféine étaient plus importantes dans l'ensilage de pulpe pure que dans les autres aliments dus au phénomène de dilution. L'ingestion fut basse et tous les animaux perdirent du poids quelque soit le type d'ensilage distribué. Dans l'essai 1 les antenais récupérèrent leur poids initial après 15 jours de pâturage à la fin de l'essai. Dans l'essai 2 le poids de départ pu être récupéré après 9 semaines d'alimentation, avec des gains de 75 g/j à 154 g/j.

Introduction

A major constraint to animal production in Ethiopia is inadequate nutrition. Animals are normally fed on natural pasture and crop residues of low feeding value. Efficient utilization of agricultural and agro-industrial by-products for animal feeding could improve nutritional status. Pulp is an important by-product in coffee growing areas. In the Jimma region almost 66 000 quintals of coffee are wet processed at 21 stations and 25 000 quintals are dry processed at 29 stations by producer cooperatives each year (Ministry of Coffee and Tea, 1984). About 69 000 quintals of pulp are produced as a by-product. In addition, large quantities of pulp are produced by the Ministry of Coffee and Tea, the Institute of Agricultural Research and other organizations throughout the region. Coffee pulp has a promising role in livestock feeding if it can be efficiently and economically dehydrated (CATIE, 1974). The pulp from dry processing is fibrous and rather poor roughage: that from wet processing has a much higher feed value (FAO, 1981) but is high in moisture and does not store well. Ensiling with other feed resources appears to be the best method of preservation and improvement of the nutritive value of pulp.

The major objective of the current study was to evaluate the nutritive value for sheep of wet processed coffee pulp ensiled on its own or in combination with different levels of sugarcane stem, sugarcane top and elephant grass (Pennisetum purpureum) .

Materials and methods

Silage preparation

In Experiment l wet processed coffee pulp was sun-dried for about 8 hr to reduce its moisture content. A mixture of 0.3 kg urea, 2.0 kg chopped sugarcane stem, 7.5 kg cow dung and 7.5 kg water was prepared 48 hr before ensiling and added to increase the nitrogen content. Adequate quantities of sugarcane stem and sugarcane top were chopped. Four treatment silages (Table 1) were prepared by ensiling the materials in plastic-lined pit silos.

The design of Experiment 2 was based on the results of Experiment 1 with different levels of either sugarcane top or elephant grass being used in combination with the sun-dried pulp (Table 1). A urea solution was used to increase content of nitrogen.

Experimental animals

In Experiment 1, 32 yearling rams were purchased and treated against internal parasites. The sheep were eartagged, weighed and divided into 8 groups of 4 of approximately equal average weight (20.7 kg). Each group was housed in experimental pens. The treatment silages were fed to the animals in a completely randomized design with 2 replicates.

Table 1. Composition of coffee pulp silages in Ethiopia.

Ingredients (%)

Treatment

Experiment 1

Experiment 21)

T1

T2

T3

T4

T1

T2

T3

T4

Coffee pulp

100

85

42.5

42.5

50

30

50

30

Sugarcane stem

-

-

42.5

-

-

-

-

-

Sugarcane top

-

-

-

42.5

50

70

-

-

Elephant grass

-

-

-

-

-

-

50

70

Additives

-

15

15.0

15.0

-

-

-

-

Note:

1. 0.3 kg urea solution/100 kg ensiled materials was added to each silage.
2. Mixture of 0.3 kg urea, 2 kg chopped sugarcane stem 7.5 kg cow dung and 7.5 kg water.

In Experiment 2 a further eight groups of four sheep (average weight 18.5 kg) were used in a completely randomized design with 2 replicates. A digestibility trial with a 10 d collection period was included in this experiment.

In both experiments water was available permanently and silage was offered at 10% above intake. Ort and faeces were collected and weighed twice a day. Feed intake was measured daily and body weight was recorded weekly throughout the experiments.

Chemical analysis

Silages and faeces were oven dried at 65°C for 72 hr. After grinding to pass through a 1 mm screen, dry matter, crude protein, fat, ash, crude fibre and nitrogen-free-extract were determined by proximate analysis (AOAC, 1955). Neutral-detergent fibre (NDF), acid-detergent fibre (ADF), cellulose, hemicellulose, lignin and ADF-nitrogen were determined by the method of Goering and van Soest (1970). Silage soluble sugar content was determined by the method of AOAC (1970).

Statistical analysis

Analysis of variance was carried out by Fisher's method (Snedecor and Cochran, 1972), with Duncan's multiple range test being used to group treatment means where F values were significant.

Results and discussion

Fermentation characteristics

The fermentation characteristic and chemical composition of the treatment silages are shown in Tables 2 and 3.

Appearance and colour were characteristic of silage having undergone adequate anaerobic fermentation. There was a change in colour of the coffee pulp from brown to black when the silages were exposed to air. It has been indicated elsewhere (Bressani, 1979) that fresh or properly ensiled coffee pulp, on contact with air, changes from the deep blood red colour it is when fresh to a dark brownish or blackish hue. This change in colour has been attributed to enzymatic browning reactions caused by oxidation of the polyphenols to quinones which in turn combine with free amino-acids and proteins to give dark-coloured complexes. The free polyphenols bind proteins and digestive enzymes and may interfere with the metabolic activity of microorganisms (Murillo et al, 1977).

Table 2. Fermentation characteristics and chemical composition of coffee pulp silages (Experiment 1) in Ethiopia.

Item

Treatment1)

T1

T2

T3

T4

Original colour

Brown

Brown

Brown

Brown

Colour after exposure to air

Black

Black

Dark

Dark

pH

4.1

4.7

3.8

4.8

Dry matter (%)

92.0

91.0

90.0

89.0

Crude protein (N x 6.25)(%)

11.0

14.0

11.0

9.9

Crude fibre (%)

19.6

20.3

26.0

27.0

Ether extract (%)

3.0

2.8

1.8

2.3

Nitrogen free extract (%)

55.4

51.3

57.1

51.8

Ash (%)

11.0

11.6

7.1

10.0

Sugar (g)

15.0

16.0

12.0

20.0

Caffeine (%)

0.50

0.44

0.33

0.23

Caffeine N (%)

29.0

29.0

29.0

29.0

Note: 1. See Table l for composition of silages.

Table 3. Fermentation characteristics and chemical composition of coffee pulp silages (Experiment 2) in Ethiopia.

Item

Treatment1)

T0

T1

T2

T3

T4

pH

4.1

4.8

4.8

4.8

4.8

Dry matter (%)

92.0

89.0

91.0

89.0

89.0

Crude protein (N x 6.25) (%)

11.0

9.4

11.9

9.9

12.2

Cellular content (%)

54.0

38.0

28.0

32.0

26.0

NDF (%)

46.0

62.0

72.0

68.0

74.0

ADF (%)

41.0

49.0

56.0

54.0

58.0

Hemicellulose (%)

5.0

13.0

16.0

14.0

16.0

Cellulose (%)

30.0

33.0

39.0

38.0

35.0

Lignin (%)

18.0

11.0

9.0

12.0

10.0

ADF-Nitrogen (%)

2.04

1.37

1.13

1.34

1.12

Caffeine (%)

0.5

0.16

0.11

0.16

0.11

Caffeine N (%)

29.0

29.0

29.0

29.0

29.0

Ash (%)

11.0

9.0

11.6

11.5

12.6

Note: 1. T0 is pure coffee pulp: for composition of other silages see Table 1.

The pH ranged from 3.8 to 4.8. A value of 4.8 was recorded from silage containing 50% and 70% of either sugarcane top or elephant grass. The pH values of the silages containing pulp and 50% sugarcane stem exceeded the limit (4.2) considered appropriate for good silage. The soluble sugar contents of these last 2 silages were lower than those of the other treatment silages. The better characteristics of the pulp and sugarcane stem silages as compared to the others was probably due to the higher concentrations and better utilization of sugars by fermenting micro-organisms.

Chemical composition

All silages in both experiments showed decreases in dry matter compared to the original materials. The crude protein content of the dry matter was slightly higher for coffee pulp silage containing 15% additive. The percentages of NDF and ADF were lower in pure pulp silage than in either sugarcane top or elephant grass silage. The NDF value obtained from pure pulp silage resulted from cellulose and lignin being the major cell wall fractions, whereas the NDF values of the silages containing either of the 2 forages had cellulose and hemicellulose as the major cell wall fractions.

The percentage compositions of lignin, ADF-nitrogen and caffeine were lower in the forage/ pulp silages in comparison to the pure pulp silage. Pure pulp silage had 18% lignin, this value being 3.6 times higher than that reported elsewhere in Ethiopia (Getachew Gebru, pers. comm.). This difference is attributed to the drying of the pulp which resulted in an enzymatic browning reaction and elevated lignin and ADF-nitrogen values.

Voluntary feed intake

There were no significant differences between the treatment groups fed on the silages prepared by ensiling coffee pulp in combination with different levels of either sugarcane top or elephant grass in mean daily feed consumption (Table 4). Treatment groups fed on silage containing coffee pulp alone and coffee pulp plus 15% additives had the lowest daily intake (P < 0.05). There was fluctuation in intake by the treatment groups on pure pulp silage and pulp plus 15% additive. These 2 silages induced regular and low feed intake for about 3 d to 5 d followed by unusually high intake for 1 d to 2 d which were commonly accompanied by ill health and/or death of the experimental animals. Recovered animals repeated the same pattern of intake.

Table 4. Voluntary feed intake and performance of sheep fed on coffee pulp silages (Experiment 1) in Ethiopia.

Item

Treatment1)

T1

T2

T3

T4

Dry matter (%)

17.9

15.6

15.6

18.1

Average feed intake (kg/h/d)

0.56

0.84

1.05

1.40

D.M. intake (kg/100 kg L.W.)

0.49a

0.65b

0.79b

1.21c

Average initial weight (kg)

22.1

21.8

20.7

20.8

Average final weight (kg)

19.9

19.8

19.0

20.6

Weight gain (kg)

-2

21 -2.04

-1.72

-0.2

ADG (kg/h/d)

-0.037a

-0 034a

-0.029a

-0.003b

Note: 1. See Table 1 for composition of silages: the ensiling period was 120 d and the feeding period was 90 d in each case.

Along rows, values without a suffix letter in common differ (P < 0.05).

One of the principal factors used to determine the nutritive value of feed is the quantity that animals consume when they have free access. All the animals were reluctant to consume the silage at the beginning of the experiments. Voluntary intake improved gradually with time and/or when the silage was supplemented with a small amount of wheat bran during the preliminary period. Generally the 2 treatment silages containing. 100.0.%. and 85% coffee-pulp induced low voluntary intake as compared to those containing less or equal to 50% pulp (P < 0.05).

Similar results have been reported by other authors. One of the limitations to the use of coffee pulp as an animal feed is the reluctance of animals to eat it when it is supplied as the main ingredient. The low intake of pulp is due to its low palatability and, probably, to adverse effects on digestion and the metabolism of the animals (Squibb, 1950). The low protein digestibility of coffee pulp has a negative effect on nitrogen retention and affects nitrogen status and voluntary intake (Bressani et al, 1972). Other factors that apparently affect consumption and utilization of pulp are the time during which it is consumed and the method employed to introduce it into the ration (Vargas, 1974).

Animal performance

In both experiments animals lost weight whichever silage was fed. In Experiment 1 the weight loss by the group assigned to equal parts of pulp and sugarcane top ensiled with 15% additive was less than the others (P < 0.05). The group fed on this silage recuperated and regained its average initial weight of 20.7 kg during the sixth week of the experimental period. The groups fed on the other 3 silages regained average initial weight following 15 d of grazing after the end of the experimental period (Figure 1).

In Experiment 2, body weight decreased in all the treatment groups during the first 8 wk of the trial. There was improvement in both feed consumption and animal performance after this period. The groups fed on elephant grass/pulp silages recuperated faster than the others (P < 0.05). Very similar protein digestibility coefficients were obtained from pulp ensiled with equal parts of either of the 2 forages (Table 5).

Figure 1. Weight changes of sheep on different types of silage in Experiment 1 in Ethiopia.

Table 5. Voluntary feed intake and performance of sheep fed on coffee pulp silages (Experiment 2) in Ethiopia.

Item

Treatment 1)

T1

T2

T3

T4

Dry matter (%)

16.9

17.7

23.0

25.4

Average feed intake (kg/h/d)

1.3

1.36

1.08

1.00

D.M. intake (kg/100 kg L.W.)

1.16a

1.45b

1.45b

1.6c

Average initial weight (kg)

19.2

18.0

18.5

18.4

Average final weight (kg)

21.45

20.34

22.73

23.02

Weight gain (kg)

2.25

2.34

4.23

4.62

ADG (kg/h/d)

0.025a

0.026

0.037b

0.051c

Coefficient of protein digestibility

4.9

7.4

5.6

7.5

Note: 1. See Table 1 for composition of silages: the ensiling period was 120 d and the feeding period was 90 d in each case.

Along rows, values without a suffix letter in common differ (P < 0.05).

The performance of animals on the silages containing 50% and 70% sugarcane top seemed to be affected by urea in general. The weight gain by the group fed on silage containing 70% sugarcane top is misleading due to the occurrence of urea toxicity and the death of the better performing animals.

The specific causes of the adverse effects of coffee pulp on animal performance are unknown. Substances present in the coffee pulp such as caffeine, tannins, other polyphenols and potassium are possibly implicated in these effects (Cabezas et al, 1979).

Three factors appear to be important in relation to caffeine and the effects observed in various animals: the relatively high concentration of nitrogen in caffeine; its known effect of stimulating increased activity; and its diuretic effect (Bressani, 1979). Caffeine levels of 0.12% in ruminant calves did not cause adverse effects but higher levels produced a significant decrease in growth as a result of lower feed consumption (Cabezas et al, 1977).

In the current study, the caffeine concentrations of the treatment silages ranged between 0.23% and 0.50% in Experiment 1 and between 0.11 and 0.16% in Experiment 2. The nitrogen content of the caffeine was about 29%. This means that caffeine nitrogen (Experiment 1) was present in amounts of about 0.07% to 0.15% which is equivalent to 4% to 9% of the total crude protein content of the silages. Furthermore, a relatively low coefficient of protein digestibility ranging between 4.9 and 7.5 was obtained from the treatment silages in Experiment 2.

Adverse effects on the animals

Significant mortalities were recorded in the groups fed on the silages containing pure coffee pulp and coffee pulp plus 15% additive. Almost all the mortalities occurred following the days of high feed intake. Postmortem examination results indicated a severe bloat. Emaciation and abnormal hair structure were pronounced and black coloured diarrhoea resembling poultry droppings was noted in the treatment groups fed on these 2 silages.

Acknowledgements

The International Foundation for Science provided partial funding for this project. W/t Messeret Mantegaftot assisted in data collection and laboratory analysis.

References

AOAC 1955. Official methods of analysis (8th edition). Association of Official Analytical Chemists, Washington DC, USA.

AOAC 1970. Official methods of analysis (11th edition). Association of Official Analytical Chemists, Washington DC, USA.

Bressani R. 1979. Antiphysiological factors in coffee pulp. Coffee pulp composition, technology and utilization. International Development Research Centre, Ottawa, Canada.

Bressani R. Elias L G and Brenes R A. 1972. Improvement of protein quality by amino acid and protein supplementation. In: E J Bigwood (ed.), International encyclopaedia of food and nutrition. Protein and amino-acid functions. Volume 12. Chapter 10. Pergamon Press, Oxford, UK.

Cabezas M T. Vargas E, Murillo B and Bressani R. 1977. Utilization of coffee fruit without seeds (coffee pulp) in ruminant feeding. First international symposium on feed composition, animal nutrient requirements and computerization of diets. Utah State University, Logan, USA.

Cabezas M T. Vargas E, Murillo B and Bressani R. 1979. Utilization of coffee pulp in ruminant feeding. Coffee pulp composition, technology and utilization. International Development Research Centre, Ottawa, Canada.

CATIE 1974. Primera reunion international sobre la utilisacion de los subproductors de cafe en alimentacion animal y atras aplicaciones agricoles e industrials. Informe final. Centro Agronomico Tropical de Investigacion y Ensenanza, Turrialba, Costa Rica.

FAO 1981. Tropical feeds. Food and Agriculture Organisation of the United Nation. Rome, Italy.

Goering H K and van Soest P J. 1970. Forage fiber analysis. Agricultural Handbook No. 379. Department of Agriculture, Washington DC, USA.

Ministry of Coffee and Tea 1984. Annual report. Regional Headquarters, Ministry of Coffee and Tea, Jimma, Ethiopia.

Murillo B T. Cabezas R. Jarquin R and Bressani R. 1977. Effect of bisulfite addition on the chemical composition and cellular content fractions of dehydrated coffee pulp digestibility. Journal of Agricultural and Food Chemistry 25: 1090-1092.

Snedecor W G and Cochran G W. 1972. Statistical methods (6th edition). Iowa State University Press, Ames, USA.

Squibb R L. 1950. Present status of dried coffee pulp and coffee pulp silages as animal feed. Instituto de Agropecuario National, Guatemala City, Guatemala.

Vargas E. 1974. Valor nutritivo de la cafe. Tesis Magister Scientificas. Universidad de San Carlos de Guatemala, San Carlos, Guatemala.


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