1- Introduction

Ph.D Thesis Fouda 2008

1- Introduction Sugar cane bagasse (SCB) is a secondary by-product of sugar cane extraction factories. It is used in the manufacture of pressed fibrous woods, paper pulp and as fuel. Bagasse represents 30-32 % of the sugar cane plant (Barnes, 1980). The annual production of SCB in Egypt is in the order of one million metric tons / year (EL-Shinnawy, 1990 and Ministry of Agriculture, Egypt 2000). There is a possibility of using bagasse in livestock feeding, while the use of by-products in animal nutrition is a necessity, since it may increase the availability of food for mankind as well as avoid accumulation that contributes to environmental problems. Sugar cane bagasse is the most abundant byproduct in Egypt. Poor intake, due to low digestibility and low energetic density, are considered the main reasons for unsatisfactory performance of animals fed such roughage. Sugar cane bagasse is not being used at present, and generally is burned. The high lignin content is a challenge, and the development of a method to upgrade bagasse as a digestible fiber source or as a substrate for single-cell protein production would be useful. There is a wide gap between the available feedstuffs and farm animals requirements. The available local feedstuffs are not sufficient completely to cover the nutritional requirements of the Egyptian live stocks. Due to the annually increased prices of the available feed resources; nutritionists do their efforts to improve the nutritional values of such resources. In addition, they are

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Ph.D Thesis Fouda 2008 looking for contribution to the available negligible agricultural by-products to provide additional marginal resources. Different treatment techniques and methods are being applied to improve the nutritional values of the additional roughage resources. Numerous attempts were being applied to modify such recycled wastes, using different chemical and biological methods to enrich its nutritional values to be recycled and recovered before being incorporated in animal feeds. Biological and chemical treatments are not new techniques, but became indispensable, especially with the increased marginal wastes, which are not ultimately utilized in animal feeds such as sugar cane bagasse. Thus, the objectives of the present study are to find out new methodology and in combination with either chemical or biological treatments to maximize the nutritional values of such waste materials. Three fungal strains and some chemical substances such as urea, hydrochloric acid and calcium hydroxide were used as pretreatments to sugar cane bagasse, in order to use such improved materials as an available animal feeds. The optimum level and concentration/ each treatment were also tested In vivo degradability tests were made to obtain additional informations about the effect of such treatments on the nutritional value of treated sugar cane bagasse. The effect of the supplementation on the nutritional degradability of the sugar cane bagasse to identify the available quantity and quality of such materials was also justified. Economic evaluation was also being considered so as to justify the different chemical and biological treatments to be applied by small producers.

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Ph.D Thesis Fouda 2008

2- REVIEW OF LITERATURE 2.1. Agricultural by-products and their characteristics: The agricultural by-products consist of major proportions of cellulose and hemicellulose, while the rest comprises lignin, nitrogenous compounds, and ash. Even though these residues contain enough cellulose to make them an excellent source of energy for ruminants, they are poor quality feed in their natural state because of their low protein content (Khilberg, 1972). The use of low quality roughages in animal feeding is characterized by low digestibility and low voluntary intake and to improve both of them, it is important to breakdown the linkages among cellulose and lignin by mechanical, chemical or biological treatments . Recently, the production of microbial protein from agricultural crop residues received the attention of several workers (Garg and Nveelakanton, 1981) . Han and Ciegler (1982); Theander and Aman (1984) reported that, lignocellulosic materials consists of cellulose, hemicellulose and lignin as main components, in the ratio 4:3:3 . These residues also contain ash and low content protein. Change (1987) mentioned that, lignocellulosic materials are complex insoluble molecules made up of aromatic building blocks resistant to break down. This complex consists of three main components; cellulose, hemicellulose and lignin with varying proportions. Chahal (1991) mentioned that, most of crop residues contain 30-45 % cellulose, 16-27 % hemicellulose , 3-13 % lignin and 3.6- 7.2 % crude protein.

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Ph.D Thesis Fouda 2008 Agricultural residues from the major component of feed and fodder base available for feeding ruminant livestock in the develop world . Such residues are characterized by low energy and protein concentration, high lignin content, low voluntary intake, poor digestibility and utilization and presence of antinutritional factors (Krishna et al., 1998).

2.2. Available roughage materials in Egypt and its utilization in animal feeding: In Egypt, there are about 21 million tons of plant by-products produced annually (Deraz, 1996). Although wheat straw and rice straw are already being fully utilized by many farmers, either for bedding poultry farm (wheat straw in particular) or for feeding livestock, yet corn stacks, corn cobs and cotton stalks are not being utilized on large scale. El-Shinnawy (1990) and Hathout and ElNouby (1990) found that, only 4.0 to 4.3 million tons of crop residues are used for feeding ruminants. The proximate amounts of some agricultural residues produced annually in Egypt are listed in Table (1). The problem of feeding straws and other fibrous by products for animals, which limits their use in animal ration formulation can be summarized as follows:, (1) low protein content, (2) high crude fiber and (3) poor palatability and (4) low digestibility . Theander and Aman (1984) stated that, the low digestibility of such materials is due to their high content (on DM basis) of cellulose (30-40%), hemicellulose (5-35%) and lignin (10-15%) . Thus to improve digestibility and nutritive value of crop residues different mechanical, chemical and biological methods should be tested.

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Ph.D Thesis Fouda 2008 Table (1) Fibrous agricultural residues in Egypt (million tons / year) : References

Agricultural by-products

Hathout

AbouAkkada

Ali- et al

ElShinnawy

Hathout and El-Nouby

1988

1990

1990

1984

1988

2.49

-

2.900

2.90

-

Rice straw

-

2.500

2.500

2.500

-

Bean straw

-

-

0.350

-

-

Barely straw

-

-

0.147

-

-

Lentil straw

-

-

0.012

-

-

Peace straw

-

-

0.0142

-

-

Berseem straw

0.75

-

0.167

0.90

-

Maize stalks

350

3.300

3.500

3.500

3.100

Sorghum stalks

1.20

-

0.970

1.20

1.00

Cotton stalks

-

2.200

-

-

1.400

Seasum stalks

-

-

0.050

-

0.060

Corn cobs

0.6

0.567

0.600

0.600

0.620

Rice hulls

-

0.500

0.400

0.50

0.572

Wheat straw

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Ph.D Thesis Fouda 2008 Rice bran

1.00

-

-

0.50

-

Sugar cane bagasse

1.00

2.00

1.00

1.00

2.500

Beet pulp

-

0.640

-

-

-

Fruit by-products

-

1.100

-

-

-

Feed resources are the main component of animal production . Annual feed resources in Egypt covered only 75.6% of self sufficiency as TDN and 11.0 - 12.3% as DCP ( Abou Akkada, 1984). He mentioned also that, using all roughages produced could annually realize the self sufficiency from feedstuffs in the year 2000 . On the other hand Hathout and El-Nouby (1990) mentioned that, 4.0 4.3 million tons of crop residues are used for feeding ruminants out of annual production of 15.2 million tons; approximately two thirds of the crop residues are burned or wasted, which lead to environmental pollution, causing health hazards . The average production of some roughages like, rice straw is 2.5 million tons , sugar cane bagasse is one million tons and banana by-products is 1.7 million tons, annually (Ministry of Agriculture, 1996) . While (Statistics of Delta Sugar Cane Company 2000) attributed that, in Egypt, the annual production of these residues (sugar cane bagasse) was estimated to be more than 170.000 tones in year 2000. 2.3. Improving utilization of low quality roughage:

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Ph.D Thesis Fouda 2008 Utilization of poor quality roughages may be increased by various pre treatments (Devendra, 1985). In recent years, considerable attention has been given to improving utilization of low quality roughages through mechanical, biological and chemical processes, microbial and enriching treatments. The importance of such improvements in animal feeding system warrants even more attention in the developing countries (Wanapat, 1981). Many procedures have been tested and modified and new methods have previously been recommended, especially for use with chemical treatments. Treatments with chemicals such as sodium hydroxide (Jackson, 1977) and /or urea. (Verma, 1983) has been shown to improve the nutritive value of cereal straws by increasing their intake and/or digestion . The best way to utilize lignocellulosic materials seems to be the bioconversion by organisms having lignolytic activities such as several mushroom species (Zadrazil, 1977). Solid state fermentation of lignocellulosic materials by white rot fungi is receiving more attention because of their capacity to remove lignin preferentially (Pilon et al., 1982). White rot fungi are capable of breaking down cellulose and hemicellulose (Agosin and Odier, 1985). Thus, some of white rot fungi like phanerochaete chrysosporium degrade lignin to extent of 65-70% (Agosin et al., 1986). The white rot fungi are known to utilize lignin as well as cellulose. Thus, the pretreatment of lignocellulosic materials will be necessary for the more efficient bioconversion of carbohydrates into microbial mass. Many researchers described physical, chemical and biological treatments to achieve this target (Chahal et al., 1980; Kamara and Zadrazil, 1986 ; Ali et al., 1987 ; Kamara and Zadrazil, 1988). 7

Ph.D Thesis Fouda 2008

2.4. Pre-treatment of sugar cane bagasse: Pre-treatment of bagasse has often been found useful to improve its digestibility and easy access for microbial attack (by removing core and noncore lignin fraction) (Alani and Smith, 1988; Doran et al., 1994). The pretreatment results in enlargement of the inner surface utilization and/or degradation of hemicellulose and lignin. This leads the fractionation of the three components and opening of cellulose structure. Several physical and chemical methods are employed for the pre-treatment, which include steam explosion, gamma radiation, treatment with alkali, hydrogen peroxide, solvents, etc. Among these, chemical pre-treatments (e.g., treatment with alkali such as NaOH solution) have been found effective and economical. Rodriguez et al., (1992) treated bagasse (pith) with a solution of sodium hydroxide in such a low volume that no free liquid was present. They referred it as a dry pre- treatment and compared it with a wet pre-treatment. Maximum digestibility was obtained with both of dry and wet pre-treatment. Maximum digestibility with dry and wet pre- treated bagasse was 75% and 71%, respectively. Biomass production was also higher in the dry process. Rodriguez and Diazcervantes (1994) compared various chemical solutions, such as hydroxides of sodium, ammonium, and calcium and hydrogen peroxide, for their efficiency of use in a dry process, which revealed fermentation data in decreasing order as NaOH, Ca (OH)2, NH4 OH, and H2O2. Bravo et al., (1994) treated bagasse with water or alkali at three liquid/solid ratios before using it as substrate for microbial protein production. The treatment significantly enhanced fungal growth compared to untreated bagasse. 8

Ph.D Thesis Fouda 2008 Aiello et al., (1996) also used sodium hydroxide at various temperatures to pre-treat the bagasse for fungal cultivation. Thereafter, Du-toit et al., (1984) compared pre-treatments of bagasse with dilute alkali and acid for the determination of the monosaccharides present in bagasse hemicellulose. The pentosan fraction of the bagasse was successfully hydrolysed and extracted with 5% (m/v) HCI. Treatment with dilute alkali resulted in 39.8% solubilization of bagasse, but only about 72% of the available hemicellulose could be extracted in this way. A thermochemical pre-treatment of bagasse involved autoclaving with a binary solvent, composed of water and organic solvent having an upper critical temperature (UCT) on the mutual solubility curve. The pre- treatment was termed as ‫ ؛‬UCT-solvent pre-treatment, and proved to be of significant potential (Kurakake et al., 1991). (Azzam, 1989 and Amjed et al., 1992) studied the pre-treatment of bagasse with gamma irradiation, coupled with an acid or alkali, which resulted in improved production of biomass protein and in vitro rumen digestibility. King et al., (1987) studied the possibilities of a steam explosion pretreatment of bagasse in terms of hemicellulose solubilization and enhancement of enzymatic hydrolysis. The pre-treatment led to a significant improvement of sugar yield through enzymatic saccharification.

2.5. Chemical composition of sugar cane bagasse: Chemical composition of sugarcane bagasse % as reported by some authors is shown in Table (2). Their findings showed that sugar cane bagasse contains in percentages, DM ( 88.63-94.57 ) with an average of 91.30 ; CP

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Ph.D Thesis Fouda 2008 ( 1.0-3.95 ) with an average of 2.48 ; EE ( 0.7-4.05 ) with an average of 2.18 ; CF ( 26.72-51.78 ) with an average of 38.17 ; N-free extract ( 36.82-58.6 ) with an average of 48.59 ; OM , ( 85.8-94.69 ) with an average of 90.62 ; Ash ( 2.25-9.95 ) with an average of 5.01 ; ADF, ( 59.0-65.77 ) with an average of 57.88 and NDF, ( 80.95-86.0 ) with an average of 83.47 . Table (2) Chemical composition of sugar cane bagasse % by some authors: Authors

DM

CP

EE

CF

NFE

OM

Ash

ADF

NDF

Abu-Raya ( 1967 )

89.5

1.5

0.8

41.1

42.4

85.8

3.7

─

─

Marshall & Vanhor (1975) AbdleMalik et al.,( 1978 )

93.8

3.1

─

34.0

─

─

3.3

─

─

92.47

2.95

1.85

26.72

58.6

90.12

2.25

─

─

Shakweer ( 2003 )

94.57

2.66

4.05

36.78

48.75

92.44

7.56

65.77

80.95

Bassuny et al., ( 2003 )

88.63

2.26

3.83

51.78

36.82

94.69

5.31

─

─

Preston ( 2003 )

91.0

1.0

0.7

49.0

─

─

3.0

59.0

86.0

Boraei ( 2003 )

89.14

3.95

1.85

27.85

56.40

90.05

9.95

─

─

Average

91.30

2.48

2.18

38.17

48.59

90.62

5.01

62.38

83.47

Sidhu and Sanhu (1980) stated that, sugar cane bagasse was composed of 36.3 % hemicellulose, 28.3 % cellulose, and 21.2 % lignin. However, Dekker and Wallis (1983) found that, it was consisted of 20-30% heteroxylane, 40-50 % cellulose, 24 % lignin, and 2.5 % ash.

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Ph.D Thesis Fouda 2008

Chemical composition of sugar cane bagasse and fiber fractions reported by numerous authors , 1- Gado,(1999) 2- Shoukry et al., (1985) 3- Hamissa et al., (1985) 4- Abd El-Ghani, (1999) were as follows (Table 3). Table (3) Chemical composition and fiber fractions of sugar cane bagasse: Chemical composition % Authors

DM

1

-

2

93.9

3

92.1

4

75.0

CP

Fiber fraction

EE

CF

NFE

OM

Ash

ADF

NDF

ADL

Hemice.

Celul.

3.0

3.1

42.6

-

92.3

-

64.4

78.6

10.4

54.0

14.2

1.7

2.4

45.2

46.0

95.3

4.7

57.7

84.5

18.5

26.8

39.2

1.8

1.2

56.7

37.3

97.0

3.0

63.7

91.9

15.6

28.2

48.1

4.1

1.1

37.2

54.5

96.8

3.2

-

-

-

-

-

2.5.1. Digestibility coefficients and nutritive values of sugar cane bagasse: Data obtained from some investigators are mentioned in Table (4) . Table (4) The digestion coefficients and feeding values of sugar cane bagasse:

Feeding values

Digestion coefficients % Authors

DM

CP

EE

CF

OM

ADF

ADL

Hemice.

Celul.

TDN

DCP

1

59.4

59.4

90.8

49.6

62.5

46.8

-

22.3

53.8

10.1

1.8

2

24.1

-

-

-

-

91.9

63.7

15.8

28.2

48.1

-

3

21.5

-

-

-

84.5

57.7

18.5

26.8

39.2

-

-

1- Gado,(1999) 2- Hamissa et al., (1985) In Situ 3- Shoukry et al., (1985) In Situ .

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Ph.D Thesis Fouda 2008 Reddy et al., (1993) evaluated that, the nutritive value of ground sugar cane bagasse without or with subsequent pelleting, and fed to sheep and goats. It was concluded that sheep DM intake was higher (P