Two experiments were conducted to evaluate the nutritive value and enzyme supplementation of sorghum brewer‟s waste (SBW) in broiler diets. In Experiment I, 225 one-week old broiler chickens with an average initial live weight of 73g were fed diets containing graded levels of SBW. There were five dietary treatments for both starter and finisher phases. The treatments were replicated three times with fifteen birds per replicate and a total of forty five birds per treatment in a completely randomized design. Treatments 1, 2, 3, 4 and 5 contained 0, 10, 20, 30 and 40% SBW, respectively. Results showed that at the starter phase, there were no significant differences (P > 0.05) among the treatments up to 40% SBW while the finisher birds performed better in terms of final weight and weight gain up to 30% level of inclusion. Digestibility of crude protein and crude fibre were better up to 20% and were similar to those fed 30% inclusion of SBW. Dietary treatments had significant (P < 0.05) effect on live weight, dressing percentage, breast, thigh, back, gizzard, liver, intestinal length and intestinal weight. At 40% level of SBW, thigh, back, gizzard, liver, intestinal length and intestinal weight were highest. In Experiment II, 225 one-week old broilers with an average initial live weight of 80g were used to evaluate the effect of Rovabio® enzyme supplementation at 0.01% on the performance, carcass characteristics and digestibility of nutrients by broilers fed diets containing 0, 30, 35, 40 and 45% SBW in Treatments 1, 2, 3, 4 and 5, respectively. Design and management of experimental birds were same as described in Experiment I. Results obtained at the starter phase showed that Rovabio® enzyme supplementation significantly (P < 0.05) affected feed intake and feed cost per kilogram gain. Average feed intake was highest in birds fed 40% and similar to those fed 45% SBW plus enzyme, respectively while Feed cost per kilogram gain was lowered in birds fed 35 and 45% SBW. At the finisher phase, enzyme supplementation significantly (P < 0.05) affected feed intake, feed conversion ratio and feed cost per kilogram gain. Average feed intake was highest up to 30% and similar to those fed 35% SBW. Feed conversion ratio was best with birds fed 40 and 45% SBW and significantly (P < 0.05) lower than birds on the control diet. Dietary treatments had no effect on the final weight, weight gain and mortality rate of the birds. Birds on 35% SBW plus enzyme had highest digestibility in terms of crude protein and crude fibre and similar to those on 40%. Digestibility of ash was highest in birds fed the control diet and similar to those fed up to 40%. Significant (P < 0.05) differences were observed on the carcass parameters measured except for the live weight, dressing%, drumstick, heart, spleen, intestinal weight and length. The results from these studies suggested that Sorghum Brewer‟s Waste can be economically fed to broilers up to 33.33% as obtained using a regression analysis with the feed cost/kg gain at the finisher phase as the parameter used without inclusion of exogenous enzymes. However, the use of Rovabio® enzyme enhanced the performance of birds up to 45% inclusion level in terms of feed cost per kilogram gain.

1.0                                                          INTRODUCTION
The present trend of inflation worldwide has become the source of concern for livestock owners, as such inflationary trend often imposes adverse effects on livestock feeds and hence, on costs of producing livestock and livestock products (Nyannor et al., 2007). Consequently, one of the greatest challenges facing the African continent is the provision of sufficient food to the ever increasing population which is not matched with similar increase in food production (Fasuyi, 2005).

The increasing demand for animal protein has aroused great interest in the production of fast growing animals with short generation intervals (Apantaku et al., 1998).Obinne and Okorie(2008) reported that expansion of poultry industry in Nigeria holds the greatest promise for bridging the animal protein requirement gap prevailing in the country within the shortest possible time. Atteh (2004), reported that protein from poultry meat and egg is of good quality and is used as a standard against which other proteins are compared. Broiler chickens are fast growing species of poultry that are commonly raised to provide tender meat for human consumption.The availability of cheap and good quality protein sources remain the single most important limiting factor in poultry production in Nigeria (Bawa et al., 2003; Abeke et al., 2008).However, the rising cost of poultry feed has continued to be a serious problem. This is because feed alone accounts for about 70% of the total cost of production (Ogundipe et al., 2003). Competition for conventional feedstuffs by man, industry and livestock has contributed immensely to the high cost of these feedstuffs in the local markets. This high cost coupled with inadequate knowledge of possible alternative and cheap ingredients have been the most important factors militating against the increase in commercial poultry production in Nigeria and other developing countries (Olorede and Ajayi, 2005).

Babatunde (1986), suggested a drastic increase in the production of ingredients commonly used in livestock feeds, such as maize, soybeans, millet and others, so as to cater for the needs of both humans and animals. Where this cannot be achieved, he emphasized that attempts should be made to source for alternative feedstuffs for livestock. Therefore, the quest for exploring the use of alternative feed ingredients that are cheaper and locally available in dietary formulations to reduce production cost becomes imperative (Okeke, 2000).A characteristic of such alternative feedstuff should be its non competitive usage with man, brewery by- products fall into this category (Dowling et al., 2003).Some non- brewery alternative feedstuffs have been evaluated and found to be good replacements for the expensive conventional feedstuffs which have direct use as human food. These alternative feed sources have been utilized successfully by several animal nutritionists in the formulation of feed which include the use of cassava peel meal in rabbits (Adegbola and Oduozo, 1992), leucaena leaf in broiler diets (Dada et al., 1998), cocoa pod husk meal in cockerel diets (Nworgu et al., 2003) etc.

According to Bello (1984), brewer‟s spent grains and brewer‟s yeast are the most common by-products of the brewing industry in Nigeria. Brewers‟ dried grain (BDG), a form of brewers‟ grain is a dried extracted residue of barley malt alone or in mixture with other cereal grains, resulting from the manufacture of beer (Adebowale and Ademosun, 1981). Babatunde (1986) identified that brewers dried grains have relatively high crude protein (23.62%) compared with maize (10.15%). They are rich sources of essential fatty acids and vitamins especially B- complex vitamins and unidentified growth factors since they are by-products of fermentation. A lot of work had been carried out on spent barley grains (Almiral et al., 1995; Amin et al., 2011). However, works on sorghum brewers‟ grains are very few. The production of sorghum brewers‟ waste (SBW) is derived from sorghum used solely or in combination with other cereal grains like maize (maize-sorghum) in the production of burukutu (Dogari, 1985; Ayodeji and Fasuyi, 2005). According to Udedibie and Emanalom (1993) the striking features of the maize- sorghum based brewer‟s waste are its relatively low fibre (12.42%) and very high crude protein (28.64%) contents, deviating significantly from the crude fibre content of the conventional barley based waste which ranges between 19-22% (Alawa et al., 1990; Maertens et al., 1990).

Thousand tones of brewer‟s spent grains are turned out annually from many small and large scale breweries in the country, with only a small fraction being used by animals particularly monogastrics (Kingsell et al., 1999). Udedibie and Emanalom (1993), Ayodeji and Fasuyi (2005) have successfully incorporated 20% maize- sorghum beer residue in poultry diets. Uchegbu et al. (2010) also reported the use of 30% maize-sorghum beer residue in poultry diets without any deleterious effect on growth and production performance. The production of beer from 100% sorghum is entirely a new concept following the ban of the importation of barley in 1988 and the need to conserve maize for human consumption. Sorghum brewer‟s waste is more nutritious than the conventional barley-based by-product and would appear best suited for feeding ruminant animals, taking advantage of its high fibre content and fairly rich source of fermentable products (Maertens et al., 1990). Abdulmalik (1997) reported that sorghum beer residue from the industry can be included at a level of 15 and 20% in the diets of breeding and weanling does respectively without adverse effects on performance. In a feeding trial, Tegbe et al. (1995) fed graded levels of 0, 10, 20, 30% spent grains to weaned pigs and reported a decrease in weight gain, feed intake, feed to gain and feed cost per kilogram gain as the level of the spent grains increased in the diet. The best result on the utilization of burukutu waste was obtained at 10% inclusion level. Tegbe et al. (1995) also fed diets of 0, 12.5, 25 and 37.5% burukutu waste to adult pigs and found that performance characteristics related to feed intake, weight gain and feed to gain ratio were not affected by the level of inclusion of the waste.

On the other hand, it is expedient to note that poultry cannot fully utilize high fibre diets because they lack the digestive frame work that can elaborately digest large amount of fibre. Many researchers have proved that it is imperative to incorporate exogenous enzymes into their diets in order to enhance the breakdown of the non-starch polysaccharides (NSPs) present in fibre (Isikwenu and Bratte, 1999). Amin et al. (2011) reported 15% Brewer‟s Dried Grain (BDG) on enzyme supplemented diet for finishing broilers. Enzymes are known to increase the digestibility of fibrous feed ingredients by disrupting the plant cell walls and by reducing the viscosity of the gut contents, thereby enhancing nutrient absorption (Isikwenu and Bratte, 1999). Almiral et al. (1995) reported that the inclusion of ß- Glucanase enzyme in a diet based on barley increased the final body weight of broilers. The enzyme considered in this study was Rovabio®.

Sorghum brewer‟s waste is relatively cheap as large quantity is produced in local gin production (Awika et al., 2001). It does not require much of additional processing such as grinding before being incorporated into livestock diets and preserves the ecosystem from further pollution resulting from its disposal.

1.1       Justification
The high cost of conventional feed ingredients such as maize, millet, soybeans, groundnut and others arising from the competition between man and animals has contributed immensely to the current high cost of poultry feeds. Hence, the need to explore the use of underutilized, non-conventional and cheap energy sources like sorghum brewer‟s waste as an alternative energy source in poultry nutrition.

Poultry farmers will appreciate any ingredient that is cheap and can be harnessed for production sustainability. Consequent of this, brewer‟s spent grains which have high fibre contents are explored, thus, the need to introduce exogenous enzymes in poultry diets because they lack efficient digestive frame work to breakdown and utilize high fibre diets. Supplementation of sorghum brewer‟s waste with Rovabio® enzyme in broiler diets will enhance its effective utilization and there could be a remarkable decrease in the cost of poultry feed to the advantage of the poultry farmers in Nigeria.

1.2       Objectives of the study
This study was designed to:

1.      Evaluate the effects of using graded levels of Sorghum Brewer‟s Waste (SBW) on performance and carcass characteristics of broilers

2.      Evaluate the nutrient digestibility of the diets of broiler birds fed graded levels of SBW.

3.      Evaluate the effect of enzyme supplementation of SBW diets on performance, carcass characteristics and digestibility of nutrients of broilers.

4.      Evaluate the cost: benefit of utilizing SBW in the diets of broilers.

Ho; sorghum brewer‟s waste with or without enzyme supplementation has no significant effect on growth performance, carcass characteristics and nutrient digestibility of broiler chickens.

Ha; sorghum brewer‟s waste with or without enzyme supplementation has a significant effect on growth performance, carcass characteristics and nutrient digestibility of broiler chickens.

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Item Type: Postgraduate Material  |  Attribute: 80 pages  |  Chapters: 1-5
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