ABSTRACT
Effects of two enzymes, (Nutrase Xyla and Maxigrain) on the
utilization of two fibrous feed ingredients, (Rice and Maize Offals) were
studied in two broiler feeding experiments.
For experiment one, there were eight dietary treatments for both the
starter and finisher phases. Diet 1 was the control (0% rice offal, no
enzyme), while diet 2 was made up of 0% rice offal diet plus maxigrain
enzyme. Diets 3 to 8 were made up of the 7.5% and 15% dietary levels of
rice offal with each dietary level supplemented with either zero enzyme or
xylanase or maxigrain enzymes respectively. Enzymes were supplemented
at the rate of 100g/ton of diet. Results for the starter phase (0-4weeks)
showed that both enzymes when supplemented in the 7.5% and 15% rice
offal diets, improved the performance of broiler chicks for final weight and
weight gain over the unsupplemented rice offal diets. Broiler chicks,
however, could not effectively utilize rice offal at both 7.5% and 15% in
the diets even when supplemented with either of the two enzymes
especially when compared with the results for the control diet. At the
finisher phase (5-9weeks), the results showed that both enzymes
significantly improved (p<0.05) broiler performance at 7.5% and 15% rice
offal dietary inclusion levels above the performances of the birds on the
unsupplemented rice offal diets and of those on the control diet for final
weight, weight gain and average daily gain.
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Experiment two was also conducted using maize offal which was
fed at 0 and 25% dietary levels. For each dietary level of maize offal, three
enzyme sources were tested namely; zero enzyme, xylanase and maxigrain
enzymes. Enzyme supplementations were also made at the manufacturers’
recommended level of 100g/ton of diet for both enzymes. The broiler
starter phase lasted from zero to 4weeks while the finisher phase lasted
from 5 to 9 weeks. Results showed that both enzymes had no significant
effect when supplemented in the control diet but they both significantly
improved the performance of broilers on the 25% maize offal diet for final
weight, weight gain, average daily gain and feed-to-gain ratio up to the
levels obtained with the control diet. There were significant reductions in
feed cost (N/kg gain) in both experiments by enzyme supplementation.
Carcass analysis showed tendency for enzyme supplementation to
reduce the size of the liver. Percent Breast also increased slightly due to
enzyme supplementation of the finisher diets.
It was concluded that enzyme supplementation did not improve the
utilization of energy rich diets but improved utilization of maize offal
based diets at the broiler starter and finisher phases and of the diets
containing up to 15% rice offal especially at the finisher phase. It was also
concluded that broiler chicks cannot effectively utilize rice offal in their
diet during the starter phase whether or not the diet is supplemented with
enzymes.
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TABLE OF CONTENTS
Content page
Title page – – – – – – – – i
Declaration – – – – – – – – ii
Certification – – – – – – – – iii
Acknowledgement- – – – – – – iv
Dedication – – – – – – – v
Abstract- – – – – – – – – vi
Table of content – – – – – – – viii
List of tables – – – – – – – xi
List of figures – – – – – – – xii
CHAPTER ONE
1.0 INTRODUCTION – – – – – – 1
1.1 OBJECTIVES OF THE STUDY – – – – 4
1.2 JUSTIFICATION – – – – – – – 4
CHAPTER TWO
2.0 LITERATURE REVIEW – – – – – 5
2.1 INTRODUCTION – – – – – – – 5
2.2 THE EFFECT OF ENZYMES ON NON – STARCH POLYSACCHARIDES (NSP),
BETA – GLUCAN AND ARABINOXYLANS OF CEREAL GRAINS 6
2.3 EFFECTS OF PHYTIC ACID AND PHYTATES ON FEED UTILIZATION -8
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2.4 BENEFITS OF USING ENZYMES IN POULTRY DIETS – – 11
2.5 ENZYME TREATMENT OF DIETS CONTAINING BARLEY, RYE, WHEAT,
OATS AND CORN – – – – – – – 18
2.6 CATEGORIES OF ENZYMES USED IN THE POULTRY INDUSTRY- 20
2.6.1 Viscous grain enzymes – – – – – – 20
2.6.2 Non-viscous grain enzymes – – – – – 20
2.6.3 Phytates – – – – – – – – 23
2.7 LIMITATIONS IN THE USE OF ENZYMES – – – – 24
2.8 COMMERCIAL ENZYMES USED IN THE EXPERIMENTS- – 25
2.8.1 Nutrase xyla – – – – – – – – 25
2.8.2 Maxigrain – – – – – – – – 26
CHAPTER THREE
3.0 MATERIALS AND METHODS – — – 28
3.1 Location of the Study – – – – – – 28
3.2 Determination of the Chemical Composition of Feed Ingredients
Used – – – – – – – – – 28
3.3 Determination of the Effects of Enzymes (Nutrase Xyla and
Maxigrain) on the Utilization of Rice Offal in Broiler Diets 29
3.4 Determination of the Effects of Enzymes (Nutrase Xyla and
Maxigrain) on the Utilization of Maize Offal in Broiler Diets – 34
3.5 Carcass Characteristics – – – – – – 39
3.6 Data Analysis – – – – – – – 39
CHAPTER FOUR
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4.0 RESULTS AND DISCUSSIONS- – – – – 40
4.1 RESULTS – – – – – – – – 40
4.1.1 Proximate Composition of Rice and Maize offals – – 40
4.1.2 Effects of Enzyme Supplementations on the Performance of
Broiler Chicks Fed Rice Offal Diets – – – – 42
4.1.3 Effects of Enzyme Supplementations on the Performance of
Broiler Chicks Fed Maize Offal Diets – – – – 54
4.1.4 Effects of Enzyme Supplementations of Diets on Carcass Characteristics of
Broiler Chicken – – – – 61
4.2 DISCUSSIONS
4.2.1 Proximate Composition of Rice and Maize Offals – – 63
4.2.2 Effects of Enzyme Supplementations on the Performance of
Broiler Chicks Fed Rice Offal Diets – – – — 64
4.2.3 Effects of Enzyme Supplementations on the Performance of
Broiler Chicks Fed Maize Offal Diets – – – 67
4.2.4 Effects of Enzyme Supplementations of Diets on Carcass Characteristics of
Broiler Chicken – – – – 69
CHAPTER FIVE
5.0 SUMMARY AND CONCLUSION – – – – 71
5.1 Recommendations – – – – – – – 74
References – – – – – – – – 75
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CHAPTER ONE
1.0 INTRODUCTION
Nigeria is currently faced with short supply and high cost of
conventional feed ingredients for poultry rations. Over the years, there has
been much effort directed towards the exploitation and the use of nonconventional
ingredients in feed production. Although the nutritional values
of these feedstuffs have been extensively studied (Aletor, 1986), and the
levels of inclusion recommended, yet the levels of nutrient digestibility and
utilization of these feedstuffs by the animal have not been maximized.
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Assessment of the quality of some commercial livestock feeds have
shown non-conformity of feed contents with recommended level of nutrients
(Ogunwolere and Onwuka, 1997). Since sub-optimum levels of nutrient
intake adversely affect the performance of livestock and poultry, simple and
inexpensive strategy needs to be exploited for meeting the nutrient
requirements of animals.
Energy, which is one of the basic requirements in poultry diets, is
derived mainly from cereals. This is because they are rich in easily digestible
carbohydrates. The types of cereal grains grown in the tropics include
maize, sorghum, rice, millet and to some extent wheat (Maikano, 2005).
Nigeria is however plagued by low production and high cost of feed
ingredients, particularly maize which constitutes 50-60% of most feeds
consumed by poultry (Olayemi, 1989). The situation is however much
aggravated by the ever increasing demand for maize as staple food for man
and as an industrial raw material.
Under the prevailing circumstances, the exploitation of some agroindustrial
by-products for poultry feed formulation (maize offal, wheat offal,
rice offal, brewer’s dried grain (BDG) and others) is necessary (Devendra
and Raghavan, 1979; Bird, 1979; Oluyemi and Roberts, 1979). Agroindustrial
by-products are cheaper to use in poultry feeds since there is little
or no existing competition for them for human use.
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Most of the energy based ingredients and the agro-industrial byproducts
used in poultry feeds are of cereal origin. Whilst the majority of the
starch present in cereals is readily digested by the monogastric animals, a
large proportion of the contents are present as non-starch polysaccharides
(NSP). The major cell wall polysaccharides of concern are the - glucans in
barley and oats, the arabinoxylans in wheat and possibly other carbohydrates
such as pectin and the oligosaccharides of the raffinose family in other
feedstuffs (Marquardt et al., 1996). The viscosity developed by
arabinoxylans and -glucans is the principal factor by which they exert their
antinutritive activities. These polysaccharides may also act as a physical
impediment to nutrient hydrolysis and utilization by digestive enzymes
(Bedford, 1992). The presence of viscous carbohydrates has been shown to
specifically reduce feed intake, weight gain, efficiency of feed utilization
and apparent metabolizable energy (AMEn). They are also known to
increase water intake, beak impaction and vent plugging, the size of the
gastro-intestinal tract, the number of anaerobic microorganisms in the large
intestine and water content of digesta and excreta (Marquardt et al 1996).
The effect of dietary enzymes is influenced by the type and
concentration of the undesirable carbohydrate present in the feedstuff and
the class and age of the livestock and poultry that consume it. Younger
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animals are affected to a greater degree by the anti nutritional compounds
than the older birds and swine. The enzymes required to digest cell wall
material, including the -glucan and arabinoxylans, include Endoglucanase,
Cellobiase, Xylanase (endoxylanase- extra cellular enzyme), Acetyxylan
esterase, Glucoronidase, Arabinofuranosidase and cellobiosidase/cellodextrinase
(Forsberg et al, 1993)
The aim of this study is to determine the effects of two enzymes,
Nutrase Xyla (a Xylanase based bacterial enzyme compound supplied by
Bio-ingredients Ltd., Lagos) and Maxigrain (a multienzyme compound of -
Glucanase, Xylanase, Phytase, Arabinoxylanase and a mixture of Minerals
and Yeast) on the performance of broiler chicks fed diets containing either
rice offal at 0, 7.5 and 15% inclusion levels or maize offal at 25% dietary
level as replacement for maize in broiler diets.
OBJECTIVES OF THE STUDY
The objectives of the study include the following:
1. To determine the effect of enzyme supplementation on the utilization of
rice offal in broiler diets.
2. To determine the effect of enzyme supplementation on the utilization of
maize offal in broiler diets.
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3. To evaluate the economics of raising broiler chicks on enzyme
supplemented broiler diets containing rice offal or maize offal.
JUSTIFICATION
This study was motivated by the fact that large quantities of agro industrial
by-products are produced in Nigeria all year round but they are usually underutilized.
However, commercially prepared enzymes hold promise in improving
the utilization of these by-products by the monogastric animals and thereby
reduce the cost of feeding.
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