LITERATURE REVIEW

2.1 Origin and distribution of rabbits

The domestic rabbit, Oryctolagus cuniculus is a descendent of wild rabbits of southern Europe and North Africa (Brewer and Cruise, 1994). The rabbit is thought to have been discovered by Phoenicians when they reached the shores of Spain about 1000 BC. During this time the Romans spread the rabbit throughout the Roman Empire as a game animal. The Romans, like Spaniards of that time ate foetuses or newly born rabbits, which they called laurices. In their natural environment, rabbits are gregarious and prolific. They are completely herbivorous (eat only plants) and most actively forage in the twilight or in the dark.

Rabbits have been recognized to have a very important role to play in the supply of animal protein to humans, especially in tropical and subtropical areas (Carabano et al., 2000). Moreover, rabbits occupy a midway between ruminants and monogastric animals and can effectively utilize cellulose rich feed with ration containing less than 20% grain (Fraga, 1998). Rabbits have short breeding cycle, high prolificacy and better feed conversion efficiency which logically place them just below poultry (Hasanat et al., 2006). It was reported by Merino (1992) that world’s production of rabbit meat was estimated to be 1.5 million tons per annum. This would mean per caput annual consumption of 280g per person per year. In Africa, the leading rabbit producing countries are Morocco and Nigeria and both countries were reported to produce about 20,000 to 99,000 tons of meat per year (Merino, 1992).

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2.2 Nutrient requirements of the rabbit

2.2.1 Energy

The energy requirements for various functions (growth, gestation and lactation) have received little attention. Assuming that rabbits, like most animals voluntarily adjust their feed intake to meet their energy needs, the lack of precise data on energy requirements is perhaps of less concern in rabbit diet formulation than the lack of data on requirements of most other nutrients. Lebas (1975) studied the performance of growing rabbits fed diets of different energy content and reported that 9.5 kcal of digestible energy (DE) was required per gram of body weight gain, regardless of energy content of the diet. The data suggested that a level of 2,500kcal of DE per kg of diet will satisfy the energy needs for rapid growth (Lebas, 1975).

Rabbits can efficiently digest starch, the major carbohydrate in cereal grains. High-starch diets were reported to be incompletely digested by rabbit due to rapid transit time in the gastro intestinal tract GIT (McNitt et al., 1996). Similarly, Stevens and Hume (1995) asserted that incomplete chemical digestion of starch fed to weaner rabbits resulted in rapid microbial fermentation. This is because excess starch in the gut resulted in an extremely rapid growth of microbes. If toxin-producing microbes primarily (Clostridium spiroformes) are present in the GIT, high levels of a starchy diet may result to enteritis or possibly death (McNitt et al., 1996; Jenkins, 1999). Grains processed too finely can lead to rapid bacterial fermentation of the starch and cause enterotoxaemia, thus, a coarse grind is recommended.

2.2.2 Lipids

Lipids (fats or oil) are biological components soluble in organic solvents (Fernandez and Fraga, 1996). They can be classified as fatty acids, triglycerides, phospholipids, glycolipids, sterols, fat-soluble vitamins etc. Lipids fulfill many essential functions in the body such as providing basic materials for cellular membranes and lipoproteins, as precursor for biological

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components and source of vitamins A, D, E and K (Maertens, 1998). Rabbits require essential fatty acids such as linoleic and linolenic acids as building blocks for other unsaturated fatty acids (Fernandez and Fraga, 1996).

Signs of deficiency in essential fatty acids in rabbits include reduced growth, loss of hair, and changes in the male reproductive system which involves degenerative changes in the seminiferous tubules, impaired sperm development, and decreased accessory gland weights (Villamide, 1996).Cheeke (1974) observed a preference of rabbits on a diet with 5% corn oil over one with no added fat, there was a distinct preference for a diet with 10% added corn oil over one with 20% oil added. Arrington et al., (1974) also observed better performance with fat levels of 11 and 14% than with 2.4 and 3.6%. It appears that there is no special problem associated with feeding of fat to rabbits. The level used in feeds is thus dictated by the prevailing economic relationship between fat sources and grains.

2.2.3 Protein

Many attempts have been made to determine the exact protein requirement of rabbits. Reports obtained so far have shown a dietary requirement for ten amino acids (NRC, 1995). Aduku and Olukosi (1990b) stated that the quantity and the quality of these amino acids were not critical in rabbits as in other animals such as poultry because rabbits practice coprophagy and can adapt to low or poor protein situations. De Blas and Mateo (1998) however reported that the amino acid supply through caecotrophy has for a long time been considered adequate to support essential amino acid requirements in rabbits fed conventional diets. In lactating does, the contribution of caecotrophy has been found to make up 0.17 % of the supply of sulphur amino acid, 0.18 % of lysine and 0.21 % of threonine (Nicodemus et al., 1999).

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The most limiting essential amino acids in rabbit diets are methionine (and/or cystine) and lysine, immediately followed by threonine. A minimum of 5.4 g of total sulphur-containing amino acid /kg (4.0g digestible amino acid/ kg) was required to obtain adequate productivity in growing and non-reproducing rabbits. A higher level (6.3 g total amino acid/ kg and 4.9 g digestible sulphur-containing amino acid/ kg) was recommended for reproducing females to increase milk production, reduce the interval between parturitions and improve efficiency of feed utilization (Taboada et al., 1996). Recommended levels of lysine for lactation, maximum reproductive performance, maximum milk production and litter growth were 6.8, 7.6-8.0 and 6.0-6.4g total lysine/kg diets respectively (Taboada et al., 1994).

Various units are available for expressing protein requirements (De Blas and Mateos, 1998; Fraga, 1998; Carabano et al., 2000 and Garcia et al., 2005). Crude protein (CP) and apparent dietary protein (ADP) are the most commonly used units, for which both requirements and raw material composition are largely available (Villamide et al., 1998; Maertens et al., 2002). Rabbits have specific amino acid requirements and apparent faecal and true ileal digestible amino acids would be more reliable units. However, if increasing information is available on the amino acid concentrations of the most common raw materials it would give better information on feed inclusion levels and utilization (Carabano et al., 2008a). In practice, due to the chemostatic regulation of appetite in rabbits, nitrogen requirements are expressed in relation to dietary energy (DE) by the dietary protein (DP) which it directly correlated to body nitrogen retention and excretion.

2.2.4 Protein requirement for growth

In growing rabbits, dietary protein (DP) was estimated to be 2.9 g DP/ day/ kg LW0.75 (Partridge et al., 1989; Fernandez and Fraga, 1996; Motta Ferreira et al., 1996; Fraga, 1998). Lower DP has been found in a new strain of laboratory rabbits (2.11–2.14 DP/ day/ kg

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LW0.75), which was attributed to a lower basic metabolic rate (Lv et al., 2009). In non-reproducing adult rabbits, since specific information is lacking, the same figures as for growing rabbits may be used for DP, this vary with growth rate.

The efficiency of utilization of dietary protein intake for growth was estimated to be 0.56 (Partridge et al., 1989; Fernandez and Fraga, 1996; Motta Ferreira et al., 1996; Fraga, 1998). Overall dietary protein retention decreases linearly from 0.40 to 0.10 with increasing live weight, due to the increase in dietary protein used for maintenance (Xiccato and Cinetto, 1988; Maertens et al., 1997; Trocino et al., 2000, 2001). Lebas (1980) and NRC (1995) have recommended 12-13% crude protein for maintenance, 15-16 % for growth, 15-18 % for gestation and 17-18 % for lactation.

2.2.5 Protein and amino acids requirement

The importance of protein quality in rabbit nutrition is well recognized. For rapid growth, rabbits are dependent upon adequate quantities of dietary essential amino acids (NAP, 1977). Bacterial protein synthesis in the caecum has been demonstrated, but this protein, obtained by means of coprophagy, apparently does not make a large contribution to the essential amino acid needs of the young rabbit (NAP, 1977). The first amino acid shown to be a dietary essential was arginine (McWard et al., 1967). The essential nature of arginine, methionine and lysine has been demonstrated by Fisher et al., (1970) and Cheeke (1971). However, Adamson and Fisher (1973) have reported that the arginine requirement was over estimated in the initial studies.

Based on the above studies, there were general agreement for the following: arginine, 0.6%, lysine, 0.55%, and sulphur amino acids (methionine plus cysteine), 0.6% of the diet on as-fed basis. These levels will support a rapid growth rate of 35-40 g/day (NRC, 1995).In contrast to other simple-stomached animals, such as swine and poultry, the rabbit is able to

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utilize efficiently the protein in forage plants. Bacterial protein synthesized in the caecum has not been shown to contribute significantly to the growing rabbit’s protein needs, though it may help to maintain nitrogen equilibrium in mature animals fed poor quality proteins. Kennedy et al., (1970) demonstrated that amino acids can be absorbed rapidly from the rabbit caecum. Crude protein levels of 16, 12, 15, and 17% were recommended for growth, maintenance, pregnancy, and lactation, respectively. These values assume the use of protein of good quality to meet the essential amino acid requirements (NRC, 1995).

2.2.6 Mineral elements requirement

Calcium and phosphorus are major constituents of bone, in addition calcium has metabolic roles in blood clotting, controlling excitability of nerve and muscle tissues and in the maintenance of acid base equilibrium while phosphorus is a component of such vital cellular constituents as ATP, DNA, RNA, and phospholipids. The absorption of calcium is influenced by its level in the diet and the dietary levels of phosphorus and vitamin D (Jenkins, 1999). Dietary requirements for calcium and phosphorus for rabbits have been estimated. Mathieu and Smith (1961) estimated the phosphorus requirement for growth to be 0.22% of the diet. In an intensive study of calcium requirements, Chapin and Smith (1967a) reported maximum growth with a dietary phosphorus level of 0.37%, when 0.22% calcium was in the diet, while 0.3 to 0.40% calcium was needed for maximum bone calcification.

Rabbits are tolerant to high dietary calcium levels. Chapin and Smith (1967b) found that diets containing as much as 4.3% calcium and a calcium: phosphorus ratio of 2:1 did not depress growth and resulted in normal bone ash. A higher phosphorus level beyond this was unpalatable causing feed rejection (Chapin and Smith, 1967c). In most mammals, less than 2% of dietary calcium is excreted in the urine, but in rabbits it is higher and can range from 45-75 %. Rabbits have an unusual calcium metabolism, absorbing calcium without vitamin D

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facilitation and activation of calcium-binding proteins in the gut resulting in excess calcium being excreted in the urine (McNitt et al., 1996; Jenkins, 1999).

2.2.7 Water requirement

Water is essential as a constituent of all part of the body and without it, food cannot be digested. The maintenance of effective elimination of harmful products via the urine is dependent upon sufficient water, as it is also important in the maintenance of almost all other physiological processes. Gillespie, (1992) observed that rabbits need good supply of cool clean water at all times for the maintenance of health and rabbits usually consume 2-3 times more water than dry matter. Sanford, (1979) stated that water intake in rabbits was variable, it was higher in the young rabbits than in the old, thus a shortage of water in early life has more serious effect and even a restricted amount of water may seriously retard growth, although their water requirement can sometimes be satisfied by highly succulent rations (which is not generally desirable). He went further to recommend that it was preferable to supply fresh drinking water. Water consumption was affected by both hot and cool weather as well as salt content of the feed (Stephen, 1980). He further stated that under hot conditions feed intake reduces while water intake increases. Similarly, feed intake increases in cool conditions and water intake reduces. The decrease in water intake during cold conditions could reduce milk supply for suckling does and predispose the rabbits to digestive disorder.

2.3 Feeding behavior of the growing rabbit

From weaning (classically between 4 and 5 weeks), the daily feed intake of the domestic rabbit (fed a complete pelleted feed) increases in relation to metabolic live weight and stabilizes at about 5 months of age. It was observed that at 4 weeks a young rabbit eats 0.25% of the amount an adult rabbits eats, but its live weight is only 0.14% of that of the adult. When Belenguer et al. (2008) took reference from a 4 kg New Zealand white rabbit that was

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fed 140-150 g dry matter (DM) /day at 8 and 16 weeks they reported relative proportion in live weights were 0.62 and 1.10% respectively..

Weaning from (4–5 weeks) to 8 weeks of age gave the highest weight gain and feed conversion was optimal (Belenguer et al., 2008). Like with other mammals, the rabbit regulates its feed intake according to energy requirements. Chemostatic mechanisms were involved, by means of the nervous system and blood levels of compounds used in energy metabolism (Gidenne and Lebas, 1987). In non-ruminants, however, blood glucose level plays a key role in food intake regulation, while in ruminants the plasma levels of volatile fatty acids have a major role. Since the rabbit is a non-ruminant herbivore, the main blood component regulating feed intake is not clear, but it is probably glucose (Lebas, 1973).

2.4 Challenges in the use of non-conventional feedstuffs for rabbit

Although non-conventional feedstuffs help to reduce dependence on conventional feed resources such as maize, however they are associated with many problems which limit their effective utilization when fed to rabbits (Medugu et al., 2012). These include presence of anti-nutritional factors, seasonality of production, location and collection in relation to area of use, cost of processing and estimation of feeding value (Adebowale, 1983). Most non-conventional feedstuffs are high in fibre. Fibre levels of over 20% may cause caecal impaction and limit energy intake (Champe and Maurice, 1983). Also the presence of anti-nutritional factors has been found to have negative effects on absorption and utilization of minerals (Waghorn et al., 1994). Abeke et al. (2003) reported that some anti-nutritional factors inhibit enzymes directly thereby forming complexes with nutrients thus, rendering them indigestible to proteolytic enzymes. Anti-nutrients such as tannins were responsible for an astringent taste of feed that induces lower intake due to reduced palatability (Butler et al., 1986). Similarly, toxic factors such as cyanide in cassava and mimosine in Leucaena

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leucocephala were often present which could cause growth depression and mortality (Cheeke and Shull, 1985).

2.5 Strategies to improve the quality of non-conventional feedstuffs for incorporation in rabbit diet

2.5.1 Crop breeding

Genetic manipulation of many non-conventional feedstuffs can enrich the nutritive quality of the by-products derived from them thereby enhancing their usage in rabbit diets (Velmurugu, 1990). For example plant seed proteins can be modified to express proteins with a more desirable amino-acid composition. This was particularly important for animal feeds, where seeds engineered to produce a higher concentration of sulfur-containing amino acids could improve feed utilization (Heyer et al., 1999). Plants may also be modified to produce proteins that aid in mineral nutrition, such as hemoglobin to improve iron uptake and other specific proteins to improve calcium uptake (Topfer et al., 1995).

2.5.2 Feed processing

Feed processing is important when diets containing anti-nutrients are fed to monogastric animals (Akande et al., 2010). Feed processing can help to reduce the levels of anti-nutrients in plant feed sources to innocuous levels that can be tolerated by animals particularly in monogastric nutrition (Fasuyi and Aletor, 2005). Feed processing also provides for proper mixture of feedstuffs with supplements, increases nutrient digestibility, palatability and passage rates of ingesta. Processing methods such as cooking, soaking, fermenting, toasting, autoclaving etc could be employed to enhance the palatability of feedstuffs in rabbit diets.

2.5.3 Feed Additives

Diet formulation with non-conventional feedstuffs can affect nutrient digestibility and utilization by non-ruminants (Velmurugu, 1990). Hence the use of feed additives such as

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exogenous enzymes, fats or oil, synthetic amino acids, vitamin mineral premixes, growth promoters and also organic acids can help to enhance the nutritional quality of the feedstuffs (Rosen, 2006). Reports by Boling et al. (1998) and Radcliffe et al. (1998) have shown tremendous potentials on the use of organic acids to improve feed utilization by non-ruminant animals. Pinheiro and Gidenne (1999) reported that antibiotics modify the gut flora, suppress bacterial catabolism and reduce bacterial fermentation. Thus, leading to improved nutrient utilization and growth performance in rabbits. Maertens (1998) also reported that the use of probiotics in rabbit production is beneficial as it helps to encourage competitive growth against microorganisms, improve digestion, and also strengthen the rabbit’s immune defense.

2.6 Importance and uses of maize husk in animal feed

Maize husks left-over are either burnt or grazed by ruminants. These residues have been incorporated into ruminant diets to eliminate wastage and to improve uptake and utilization (Jokthan et al., 2009). Maize husk may be relatively poor in nutritive value compared to some other locally available residues or roughages however it is composed of cellulose, hemicelluloses and lignin that encourages its utilization as energy source in ruminant diet.

2.7 Maize husk in rabbit nutrition

The ability of rabbits to utilize cheap and non -conventional feedstuffs is an important advantage over other monogastric animals. Rabbits can sufficiently degrade substantial amounts of fibre, making dietary fibre the main constituent of rabbit feed. Rabbits can digest 65-78% fibre consumed (Harris, 1969), their digestive tract is set up to digest cellulose in the form of tough, woody stem and fibrous vegetation due to the long digestive tracts that slowly break down cellulose and process it. This inherent quality of the rabbit makes maize husk inclusion in their diet a potential non-conventional feedstuff.

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2.8 Role of fibre in rabbit nutrition

Available data showed that fibre is necessary in rabbit diets for normal functioning of the digestive tract. Rabbits require a level of crude fibre in excess of 9% for normal growth and to reduce the incidence of enteritis and diarrhea. In the study of Cheeke and Amberg (1972) it was observed that fibre levels exceeding 17% reduced energy intake. Low fibre levels predispose the animal to diarrhoea (Champe and Maurice, 1983). A crude fibre level of between 10-17% was found to support weight gain. A growth level of the 41.3g/day/animal was found to be adequate for crude fibre level of 14.8% as reported by Champe and Maurice (1983). It had been reported that rabbits were able to digest fibre relatively well, due to the presence of the caecum (Laplace, 1978). The author further stated that fibre and non-fibre components in the hind-gut were separated with the rapid excretion of the fibre in the hard faeces. The non-fibre components were digested efficiently because they were re-ingested as caecotropes and thus subjected to more than one passage through the digestive tract. It had been reported that with hind gut fermentation a high intake of high fibre diet can be achieved with nutrient requirement met by the high digestibility of non-fibre component (Laplace, 1978). Amongst factors that affect digestibility of feedstuffs, the most important factor is the amount of fibre it contains (Standford, 1979). Furthermore as the proportion of this constituent rises, the total digestibility and the individual digestibility of the various constituent of the feed fall. The reason advanced was that the fibre tends to protect the more digestible constituents from the digestive juices.

Rabbits eat hair from their body when fed low fibre diet in attempt to satisfy craves for fibre (Aduku and Olukosi, 1990b). Increase in dietary fibre help to reduce hair ball problem which reduces feed consumption. Feeding hay or other coarse roughages, also help to ―sweep‖ hair from the stomach hence preventing hair ball disease which can block the opening of the stomach and ultimately lead to death due to starvation (Sandford, 1979).

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2.9 Role of fibre in maintaining rabbit gut health

In critical role in maintaining gut health, stimulating gut motility (insoluble fibre only), reducing fur chewing, and preventing enteritis (McNitt et al., 1996; Brooks, 1997). It was reported by Cheeke (1994) that rabbits require a minimum dietary fibre level of 10 to 17% to maintain gut health. Diets with less than 10 to 17% fibre resulted in gut hypo motility, reduced caecotrophy, prolonged retention time in the hindgut and often enteritis as reported by Jenkins (1999). Thus, high-quality fibre was essential for gut health in rabbits (McNitt et al., 1996; Stein and Walshaw, 1996).

In rabbits, insoluble fibre have been widely recognized as the most important fibre fraction used to express fibre requirements and it accounts for about 65-90% of the total dietary fibre (TDF). Current recommendations stated that diets for rabbits should contain at rabbits, dietary fibre has a least 30% Neutral Detergent Fibre (NDF) and 16% Acid Detergent Fibre (ADF) (De Blas and Mateos, 2010). Lignin and to a lesser extent, cellulose remain largely undigested because their polyphenolic structure was not hydrolyzed by the bacteria in the rabbit caecum (Lebas, 1980). Lignin play a dominant role in the transit time in the gut, and increasing levels were associated with a significant reduction of the digesta retention time (Gidenne, 2003). Similarly, Gidenne et al. (2005) reported that hemicellulose and pectins were considered as digestible fiber because their digestibilities were 30 and 70%, respectively.

The retention time of hemicellulose and pectins in the caeco-colic segment was relatively short (8-12hr), thereafter these rapidly fermentable cell-wall polysaccharides play a key role in the rabbit digestive processes. Hall et al. (1997) asserted that uronic acid (a main constituent of the pectins) had been shown to modulate the fermentative activity and pH in the caecum . Hence a sufficient dietary content of these digestible fibers were necessary, in

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addition to the indigestible fraction, to optimize digestive health (Gidenne, 2010). In view of preventing digestive troubles, fibre requirements cannot be only based on insoluble fibre but also on soluble fibre.

2.10 Role of fibre in preventing digestive disorders in growing rabbit

The beneficial role of fibre in preventing digestive diseases was mostly based on the control of intestinal microflora through its effect on transit of ingesta and the availability of substrate for bacterial growth (Carabaño et al., 2008a).Álvarez et al. (2007) asserted that a range of 10-17% dietary fibre reduced mortality, improved performance, reduced incidences of diarrhoea and also improved intestinal mucosal structure. De Blas et al. (1999) reported that insoluble fibre was necessary to decrease mean retention time of digesta in the gut, dilute dietary and ileal starch content. Similarly, García et al. (2000) reported that insoluble fibre helped to dilute protein content and also reduce total microbial growth. Consequently, the type of dietary fibre could be important in promoting the growth of beneficial microflora. Dietary inclusion of soluble fibre favoured the growth of intestinal villi and the activity of enterocytes while the inclusion of lignified fibre produced structural atrophy, lower activity of intestinal cells and proliferation of beneficial microflora. According to Marounek et al. (1995) the caecal microflora of weaner rabbits were limited compared to that of adults. Hence, caecal microbes in weaner rabbits were specialized in fermentation of soluble fibrous carbohydrates such as fructans, galactans, β-glucans and pectic substances.

The need for fibre was pertinent during the post-weaning period, low fibre intake without variations of fibre nature or origin resulted in lower growth rate two weeks after weaning (Gidenne and Jehl, 1999; Pinheiro and Gidenne, 1999).The rabbit thus attempts to increase its voluntary feed intake to satisfy energy needs and reduce feed conversion. When the dietary fibre level is very high (>25% ADF), the animal cannot increase its intake sufficiently to

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meet its energy needs, thus leading to reduced growth rate, but without digestive problems. Therefore, to reduce digestive troubles in the growing rabbit and also to preserve its growth performance, adequate quantity of fibre must be supplied (Álvarez et al., 2007).

2.11 Fibre digestion and degradation by rabbits

Traditionally, fermentation of dietary fibre had been considered to be a post-ileal activity of the endogenous microflora. However, there was evidence that some components of structural carbohydrates were degraded prior to entering the caecum of rabbits (Carabano et al., 2001). This had also been observed in other non-ruminant species such as pigs and poultry (Carabano et al., 2001). The extent of pre-caecal fibre digestion in rabbits varied from 0.07 to 0.19% for crude fibre (CF) (Yu et al., 1987), from 0.05 to 0.43% for NDF (Gidenne and Ruckebusch, 1989; Merino and Carabano, 1992) and from 0 to 0.37% for non-starch polysaccharide (Gidenne, 1992; Carabano et al., 2001).

It must be pointed out that the values obtained using (NDF) and CF with respect to those obtained with non-starch polysaccharide (NSP) might have been over estimated due to solubilization and filtration of cell wall components that would be considered digested (Bach, 2001). When NSPs were analyzed, arabinose and uranic acids which were typical monomers of pectin substances were found to be largely digested before the ileum (Carabano, 2001). On the other hand Bach (2001) reported that glucose and xylose which were monomers in most fibre sources had relatively low ileal digestibility. This implies that about 0.4% of total digestible fibre (including water-soluble NSP) was degradable before the caecum (Bach, 2001).

2.12 Role of Enzyme in Fibre Digestion and Utilization

Enzymes are proteins which are able to catalyze specific chemical reactions with a minimum energy waste (Chesson and Steward, 2002). Almost all processes in biological cells need

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enzymes at specific sites. Endogenous enzymes are naturally produced by the animal or by microbes present in the digestive tract. However specific activities necessary to break down some compounds in feed are not found or are at low levels in the digestive tract. Hence, exogenous enzymes are added to the diet to breakdown these compounds. Most animal feeds contain plant materials such as cereals and vegetable proteins that are not fully digestible by the animal’s digestive system. Consequently digestion and utilization can be enhanced by addition of exogenous enzymes. Fasiullah et al. (2010) reported that exogenous microbial enzymes enhanced digestion of (NSP) breaking down cellulose, hemi-cellulose, pectins and lignified complexes thus leading to improved feed utilization and growth performance. Reports by Eiben et al. (2004), Garcia et al.(2005), Falcao-e-Cunha et al.(2007) and Bawa et al.( 2009) showed that enzyme supplementation in rabbit diet significantly improved performance and nutrient digestibility.

Rabbits require enzymes to breakdown fats, cleanse the colon, maintain proper cholesterol levels and attain peak energy levels. Tawfeek (1996) reported that the use of enzymes in rabbit rations helped to improve the performance of rabbits by enhancing efficient nutrient utilization. It was also reported by Eiben et al. (2004) that exogenous fibrolytic enzymes can promote ceacal fermentation and modify volatile fatty acid concentration in rabbits thereby maintaining good health status. El-Latif et al. (2008) asserted that in order to obtain maximum benefits from exogenous enzymes, it was necessary to ensure that the enzymes were chosen on the basis of feed composition. Enzyme cocktails containing more than one enzyme will often improve the response compared to pure, single enzymes, assuming that cost considerations were not ignored.