ABSTRACT
Two feeding trials were carried out to determine the effect of exogenous enzyme inclusion in sorghum (Sorghum bicolor) based diets for broiler chickens. The first feeding trial was conducted to determine the effect of feeding broiler chickens with two varieties of sorghum namely, Jandawa (Red sorghum) and Kaura (Samsorg 17) with or without phytase inclusion using five (5) Treatment 1 was maize based diet; Treatment 2, Jandawa based diet; Treatment 3, Kaura based diet; Treatment 4, Jandawa based diet with phytase; and Treatment 5, Kaura based diet with phytase. The second trial was conducted with five (5) diets to evaluate the response of broiler chickens fed Kaura based diets supplemented with Ronozyme® phytase, Ronozyme® protease and Roxazyme® G2 G and a combination of protease and G2 G. Treatment 1 was maize based diet; Treatment 2, Kaura based diet with phytase; Treatment 3, Kaura based diet with protease; Treatment 4, Kaura based diet with G2 G; and Treatment 5, Kaura based diet with a combination of Ronozyme® protease and Roxazyme® G2 G. Three hundred and seventy-five (375) broiler chicks were used in each trial and each allotted in a completely randomized design (CRD) to five (5) dietary treatments replicated thrice and having (twenty-five) 25 chicks per replicate. Diets were formulated to meet standard requirements. Water and the various treatment diets were offered to the birds ad libitum for the period of each experiment. Data were subjected to Analysis of Variance (ANOVA) and significant differences among treatment means were compared using the Duncan Multiple Range Test. In the first trial, the starter phase showed that chicks fed Kaura with phytase inclusion had significantly (P < 0.05) higher final body weight and weight gain. Finisher broiler chickens showed no significant (P > 0.05) differences in the final body weight, weight gain, feed intake and feed to gain ratio across all treatments. Feed cost/Kg gain for the eight (8) weeks period showed that birds fed Kaura with phytase had significantly (P < 0.05) lower cost of production. The dressing percentage was significantly (P < 0.05) highest for birds fed
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Kaura diets (T3 and T5). Diets with phytase inclusion had significantly (P < 0.05) higher tibia calcium and phosphorus contents. There were no significant (P > 0.05) difference in blood calcium and phosphorus. Results of the second trial showed that chicks fed Kaura with protease and G2 G inclusion had significantly (P<0.05) highest final body weight and weight gain. Feed/gain ratio, feed cost and feed cost/Kg gain were not significantly (P > 0.05) different. Finisher broiler chickens showed significant (P<0.05) differences in the final body weight. Kaura diet with phytase had significantly lower final body weight and dressing percentage than all the other treatments. Parameters measured for blood quality were not significantly (P > 0.05) different for all the treatments. It is concluded that phytase in Kaura based diets significantly improved growth performance of broiler chicks, enhanced bone mineralization and significantly reduced cost of production than Jandawa and maize based diets, also Roxazyme® G2 G and the combination with Protease in Kaura based diets improved growth performance for broiler starter chicks and also resulted into comparable performance with maize based diets for broiler finisher. Blood quality was not compromised. The Kaura variety of sorghum with Ronozyme® phytase, Ronozyme® protease combined with Roxazyme® G2 G inclusion can be used for effective nutrient utilization and improved growth performance by broiler chickens.
TABLE OF CONTENTS
COVER PAGE……………………………………………………………………………………………………………. i
TITLE PAGE …………………………………………………………………………………………………………….. ii
DECLARATION ……………………………………………………………………………………………………… iii
CERTIFICATION …………………………………………………………………………………………………….. iv
DEDICATION …………………………………………………………………………………………………………… v
ACKNOWLEDGEMENT ………………………………………………………………………………………….. vi
ABSTRACT …………………………………………………………………………………………………………… viii
LIST OF TABLES …………………………………………………………………………………………………… xiv
LIST OF APPENDICES ……………………………………………………………………………………………. xv
CHAPTER ONE………………………………………………………………………………………..1
1.0 INTRODUCTION …………………………………………………………………………………….. 1
Objectives……………………………………………………………………………………………… 3
Research Hypotheses …………………………………………………………………………………. 3
CHAPTER TWO ……………………………………………………………………………………………………….. 4
2.0 LITERATURE REVIEW …………………………………………………………………………… 4
2.1 Poultry……………………………………………………………… ………………… 4
2.2 Nutrient Requirement of Broiler Chickens………………………. …………………… 4
2.2.1 Energy requirement of broiler chickens ………………………………………………………… 5
2.2.2 Protein and Amino Acid Requirement of Broiler Chickens …………………………….. 7
2.2.3 Fat Requirement of Broilers ………………………………………………………………………… 9
2.2.4 Vitamin and Mineral Requirement of Broilers …………………………………………….. 10
2.3 Sorghum (Sorghum bicolor )……………………………………….. ……………… 11
2.3.1 World Sorghum Production and Trade ……………………………………………………….. 11
2.3.2 Varieties of Sorghum ……………………………………………………………………………….. 15
2.3.3 Anti-nutritional Factors in Sorghum …………………………………………………………… 15
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2.3.4 Consequences of anti-nutritional factors in Sorghum ……………………………………. 18
2.4 Enzymes…………………………………………………………. ………………….. 19
2.4.1 Sources of Enzymes …………………………………………………………………………………. 20
2.4.2 Phytase …………………………………………………………………………………………………… 21
2.4.3 Protease ………………………………………………………………………………………………….. 22
2.4.4 Roxazyme G ……………………………………………………………………………………………. 23
2.4.5 Combinations of Enzymes ………………………………………………………………………… 23
CHAPTER THREE ………………………………………………………………………………………………….. 25
3.0 MATERIALS AND METHODS ……………………………………………………………….. 25
3.1 Experimental Site………………………………………………….. ……………….. 25
3.2 Sources of Experimental Materials …………………………………………………………….. 25
3.3 Determination of Proximate Composition, Gross Energy and Anti-nutritional factors of Feed Ingredients ……………………………………………………………………….. 25
3.3.1 Determination of dry matter content …………………………………………………………… 26
3.3.2 Determination of ash ………………………………………………………………………………… 26
3.3.3 Determination of ether extract …………………………………………………………………… 27
3.3.4 Determination of crude fiber ……………………………………………………………………… 27
3.3.5 Determination of crude protein ………………………………………………………………….. 28
3.3.6 Determination of nitrogen free extracts (NFE) …………………………………………….. 29
3.3.7 Determination of Gross energy ………………………………………………………………….. 29
3.3.8 Determination of phytates……………………………………………..…………30
3.3.9 Determination of tannin ……………………………………………………………………………. 30
3.3.10 Determination of oxalate …………………………………………………………………………… 30
3.3.11 Determination of mineral content ………………………………………………………………. 31
3.4 Experiment 1: Effect of Ronozyme® Phytase on the utilization of two varieties of sorghum ( sorghum bicolor) by broiler chickens ……………………………………… 31
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3.4.1 Experimental Design and management of birds …………………………………………… 31
3.4.2 Experimental diets……………………………………………………………………………………. 32
3.4.3 Performance Study …………………………………………………………………………………… 32
3.4.4 Carcass Evaluation …………………………………………………………………………………… 32
3.4.5 Bone Mineral Analysis……………………………………………………………………………… 35
3.4.6 Digestibility Study …………………………………………………………………………………… 35
3.4.7 Determination of Serum Calcium and Phosphorus ……………………………………….. 35
3.5 Experiment 2: Response of broiler chickens fed Kaura based diets supplemented with enzymes ……………………………………………………………………… 36
3.5.1 Experimental Design and management of birds …………………………………………… 36
3.5.2 Experimental diets……………………………………………………………………………………. 36
3.5.3 Performance Study …………………………………………………………………………………… 37
3.5.4 Carcass evaluation……………………………………………………………………………………. 37
3.5.5 Digestibility …………………………………………………………………………………………….. 40
3.5.6 Haematological evaluation ………………………………………………………………………… 40
3.5.6 Statistical Analysis……………..………………………………………………..41
CHAPTER FOUR …………………………………………………………………………………………………….. 42
4.0 RESULTS AND DISCUSIONS ………………………………………………………………… 42
4.1 Proximate composition and anti-nutrients of two varieties of sorghum …………… 42
4.2 Experiment 1: Effect of Ronozyme® Phytase on the utilization of two varieties of sorghum (Sorghum bicolor) by broiler chickens…………………. ………… 44
4.2.1 Performance of broiler chicks fed two varieties of sorghum with and without enzyme inclusion (0-4 weeks)……………………………………………….. ….. 44
4.2.2 Performance of finisher broiler fed two varieties of sorghum with or without enzyme inclusion (5-8 weeks)………………………………………………… … 47
4.2.3 Performance of broiler chickens fed two varieties of sorghum with phytase inclusion (0-8 weeks)…………………………………………………………. … 49
4.2.4 Nutrient digestibility and mineral profile of broilers fed Kaura and Jandawa with and without phytase inclusion…………………………………………. ………….. 51
4.2.5 Bone and serum mineral contents of broilers fed two varieties of sorghum with and without phytase inclusion………………………………………….. …………. 53
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4.2.6 Carcass characteristics and organ weight of broiler chickens fed two varieties of sorghum with and without phytase inclusion……………………………… …….. 55
4.3 Experiment 2: Response of broiler chickens fed Kaura based diets with enzymes inclusion……………………………………………………………… ……………. 57
4.3.1 Performance of Broiler Chicks fed Kaura Based diets with Enzyme Inclusion (0-4 weeks)……………………………………………………….. …………………. 57
4.3.2 Performance of finisher broiler fed two varieties of sorghum with or without enzyme inclusion (5-8 weeks)………… …….………………………………….59
4.3.3 Nutrient Digestibility of Finisher Broiler Fed Kaura based diets with enzyme inclusion……………………………………………………………… ……………. 61
4.3.4 Haematological indices of Finisher Broiler Fed Kaura based diets with enzyme inclusion………………………………………………………………………… 63
4.3.5 Carcass Characteristics and Organ weights of Finisher Broiler Fed Kaura based diets with enzyme inclusion……………………………………………. …………. 65
CHAPTER FIVE ……………………………………………………………………………………………………… 67
5.0 SUMMARY, CONCLUSION AND RECOMMENDATION ……………………….. 67
5.1 Summary…………………………………………………………… ………………. 67
5.2 Conclusion…………………………………………………………. ………………. 68
5.3 Recommendation………………………………………………… …………………. 68
REFERENCES ………………………………………………………………………………………………………… 69
APPENDICES…………………………………………………………………………………………80
CHAPTER ONE
1.0 INTRODUCTION
The poultry industry has become an important economic activity in many countries. The biggest single expense in any system of poultry production is feed, which accounts for about 70% of total production cost per bird (Khattak, 2006). The frequent collapse of many commercial poultry farms in Nigeria have been attributed to high cost of poultry feeds (Ogundipe, 2002) and feed cost is expected to continue in the upward swing (Conolly, 2012). Sorghum grain is the third most important cereal crop grown in the United States and the fifth most important cereal crop grown in the world (USDA, 2010). Maunder (2002) reported that sorghum is a conventional crop of Africa and Asia and an introduced and hybridized crop in the western hemisphere. Sorghum’s nutritional outline includes several minerals which is unevenly distributed and is more concentrated in the germ and the seed coat. Sorghum contains some anti-nutritional factors which inhibit the use of important nutrients like protein, energy and minerals (phosphorus, calcium, zinc and magnesium) in diets. To improve the utilization of sorghum and indeed dietary nutrients in poultry diet, enzymes are put into consideration (Bedford, 1996). Enzyme inclusion in poultry feeds has been of the major nutritional advances in the last fifty years. It is the culmination of something that nutritionists realized for a long time but until 1980’s it remained beyond their reach (Khattak, 2006). Poultry naturally produces enzymes to aid the digestion of feed nutrients. However, they do not have enzyme to break down fibre completely and need exogenous enzymes in feed to aid digestion.
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The benefits of using enzymes in poultry diets include not only enhanced performance and feed conversion but also less environmental problems due to reduced output of excreta. Feed enzymes have the potential to reduce effects of anti-nutritional factors, render nutrients more available for digestion and absorption, increase energy value of feed ingredients and allow for greater flexibility in feed formulation, thus reducing formulation costs and modulating or stabilising gut microflora. Some of the enzymes that have been used over the past several years and have potential for use in the feed industry include cellulase (β-glucanases), xylanases and associated enzymes, phytases, proteases, lipases, and galactosidases (Khusheeba and Sajid, 2013). One area that has received relatively little attention is the use of combinations of enzymes such as carbohydrases and proteases to improve nutrient retention and performance of growing chickens. Logic would suggest that if the use of one enzyme can improve body weight gain (BWG) and feed conversion ratio (FCR) of chickens compared with birds that have been fed a diet containing no enzyme, the use of 2 enzymes might improve the scale and consistency of the response (Ravindran et al., 1999). The reality is somewhat different. Antagonistic (Naveed et al., 1999; Saleh et al., 2004), sub-additive (Zyla et al., 2000; Wu et al., 2004; Kim et al., 2005; Leslie et al., 2005); additive (Zyla et al., 2000; Mulyantini et al., 2005), and synergistic (Ravindran et al.,1999) effects of enzyme combinations have been reported. Clearly, this variety of responses to enzymes and combinations of enzymes is unacceptable for producers of poultry products. Therefore, it is critical that more information need to be generated that will allow tools to be developed, based on whole analysis of animal data, to show when enzyme combinations can offer an additive, sub-additive, or synergistic effect on performance parameters.
Nigeria was positioned as the number one producer of sorghum followed by the United States and India and was the fifth exporter of sorghum in the world market (FAO, 2012). The
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effective utilization of sorghum in poultry diets will therefore boost poultry production in Nigeria. It was however discovered that the performance of broiler chickens fed sorghum based diet were significantly lower compared to those fed maize based diet which could be a result of the presence of anti-nutrients (Selle et al., 2010). Hence the need to improve the utilization of sorghum based diet with single or combined enzymes inclusion.
Objectives
The objectives of this study were:
1. To evaluate the effect of two varieties of sorghum with or without phytase enzyme on growth performance, nutrient digestibility and bone mineralization of broiler chickens.
2. Evaluation of the effect of Ronozyme® phytase, Ronozyme® protease and Roxazyme® G2 G as single enzymes and their combinations in Kaura based diet on growth performance, nutrient digestibility and haematology of broiler chickens.
Research Hypotheses
Experiment 1 HO: Inclusion of phytase in two varieties of sorghum based diets has no effect on growth performance, nutrient digestibility and bone mineralization in broiler chickens. HA: Inclusion of phytase in two varieties of sorghum based diets has effect on growth performance, nutrient digestibility and bone mineralization in broiler chickens. Experiment 2 HO: Single enzyme and combination of enzymes inclusion in broiler chickens diet has no effect on growth performance, nutrient digestibility and haematology.
HA: Single enzyme and combination of enzymes inclusion in broiler chickens diet has effect on growth performance, nutrient digestibility and haematology.
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