ABSTRACT
Proximate composition of cooked sweet potato meal (CSPM) was determined using AOAC (1990) methods. Four experiments were conducted with two set of birds. The first two experiments were carried out to determine the optimum level of utilization of cooked sweet potato meal (CSPM) in broiler diets and the variety of preference in the second experiments. Two hundred and seventy one-week old broiler chicks (hubbard breed) with an average weight of 93g were randomly allotted to six dietary treatments during experiment 1, with three replicates of 15 birds per replicate in a Completely Randomized Experimental Design. The experimental diets consisted of six levels of weight for weight substitution of maize with CSPM at 0, 10, 20, 30, 40 and 50% respectively. Results showed that at the starter phase birds on 5.4% CSPM diet had higher weights than all the other treatments including the control diet in terms of final weight, total weight gain, daily weight gain and feed conversion ratio. At the finisher phase, significant differences (P>0.05) were noted in the final weight, weight gain, daily weight gain, feed conversion ratio and feed cost as the level of CSPM increased in the diet. Growth performance was significantly depressed even at 10% CSPM replacement for maize. The carcass analysis also showed significant differences (P>0.05) in most parameters, but there was no clear cut trend except for the weight of liver that increased as the level of CSPM exceeded 10%. Dietary inclusion of CSPM significantly reduced the digestibility of DM, CF, EE and ash. Fibre digestibilities decreased linearly as CSPM replacement increased from 0 – 50%, while the ash retention also decreased linearly as CSPM increased from 0 – 30% of maize replacement. There was no mortality at both phases. In the second experiment, three varieties (white, orange and yellow) of CSPM were evaluated for proximate composition and anti-nutritional factors. At starter phase, One hundred and eighty one-week old broiler chicks (Hubbard breed) of mixed
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sex with an average weight of 80g were randomly allotted to four dietary treatments with three replicates of 15 birds each in a Completely Randomized Experimental Design. The experimental diets consisted of diets formulated without sweet potato (control), 10% white-flesh CSPM, 10% orange–flesh CSPM and 10% yellow-flesh CSPM respectively. Performances of birds fed the three varieties of CSPM were better than those of birds fed the control diet at the starter phase, while at the finisher phase, significant (P>0.05) better performance was observed in the control group. They had better live weight, dressed weight, % breast, % thighs, % back cut and % shank than the values for the three varieties of CSPM. Nutrient digestibilities were generally higher in the bird fed control diet. White flesh CSPM based diet had relatively higher digestibility coefficient than orange and yellow flesh CSPM based diets. It was concluded that, broiler chickens at the starter phase can optimally tolerate a maximum of 5.4% CSPM in their diets. White-flesh variety of CSPM supported optimal performance at 10% dietary inclusion level with concomitant reduction in feed cost per kilogram. Further studies are recommended to determine replacement value of CSPM in broiler finisher diets.
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TABLE OF CONTENTS
Cover page………….…………………………………….…………………………….……..i
Title page………….……………………………………………………………….………….ii
Declaration……….………………………………………………………………….……….iii
Certification…….……………………………………………………………………….……iv
Dedication…………….……………………………………………………….….………….v
Acknowledgement …………………………………………………………….….………….vi
Abstract…………………………………………………………………………….………..viii
Table of Contents…………………………………………………………………….……….x
List of Tables……..………..…………………………………………………………..……..xv
CHAPTER ONE…………………………………………………………..……………..…1
1.0 INTRODUCTION……………….………………………………..……………………1
1.1 Research Hypothesis………………..………………………….…………….………….3
1.2 Objectives of the Study………………..…………………………………………………3
CHAPTER TWO………………….…………..……………………………………………5
2. 0 LITERATURE REVIEW……………………………….…………………………….5
2.1 Description of Sweet Potato………………………………………………………………5
2.2 Origin and Distribution of Sweet Potato……………………………………….…………5
2.3 Chemical Composition of Sweet Potato…….…………………………….……………6
2.3.1 Carbohydrates in Sweet Potato……………………………………….…………………6
2.3.2 Protein Content of Sweet Potato.………………………….….….……………………..9
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2.3.3 Lipid Content of Sweet Potato……………………………..………….……………….13
2.3.4 Vitamins Content in Sweet Potato..………..……………………….………………….15
2.3.5 Minerals Content in Sweet Potato…..………………………….…………..…………..16
2.4.0 Anti-nutritional Factors in Sweet Potato ……………..……….………….……………18
2.4.1 Trypsin Inhibitors in Sweet Potato……..……..….…………..…………………………18
2.4.2 Oxalates Content in Sweet Potato………….…………………………………………..20
2.5. The use of Sweet Potato in Poultry Feeding ……………………………………………21
CHAPTER THREE……………….…………………………….…….……………………26
3.0 MATERIALS AND METHODS…..………..…….……….………………..……….26
3.1 Experimental Site……..…………………………………………………………………26
3.2 Source of Experimental Birds…….…….…………………….…………………..……26
3.3 Experiment 1 and 2: Partial Replacement Value of Cooked Sweet Potato Meal
(CSPM) for Maize in Broiler Diets
(1-4 and 5-8weeks)………………………………………………26
3.4 Source and Processing of Sweet Potato Tubers……………………….…………….….26
3.4.1 Determination of the Proximate Composition of Raw and Cooked Sweet
Potato Meal (SPM)…………………….…………………………………….…………26
3.4.2 Experimental Diets (Experiments 1 and 2)………..…….……….………………..….27
3.4.3 Experimental Design and Management of Experimental Birds…….………..….…….27
3.4.4 Data Collection……………………..……………..…………………..………………28
3.4.5 Digestibility Trial……………..……….…………..…………….……………………31
3.4.6 Carcass Analysis………………..……………….………..……….………………….31
3.4.7 Statistical Analysis………………..…………………….………….………………….32
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3.5 Experiments 3 and 4: Comparative Performance of Broilers (1-4 and 5-8weeks)
fed Three Varieties of CSPM at 10% level of replacement……..32
3.5.1 Sources and Processing of Three Varieties of Sweet Potato Tubers……………………..32
3.5.2 Determination of the Proximate Composition of the Three Varieties of
Sweet Potato Tubers (raw and cooked)………….………….….………………………33
3.5.3 Determination of Anti-nutritional Factors of the Three Varieties of Sweet
Potato Meal (raw and cooked)……………………………………….…………………33
3.5.4 Experimental Diets (Experiments 3 and 4)……………..……….………………..….…33
3.5.5 Experimental Design and Management of Experimental Birds
(1-4 and 5-8weeks)………………………………………………………………….…37
3.5.6 Data Collection……………….………………………………………………….……..37
3.5.7 Digestibility Trial………………………………..………………………….…………..37
3.5.8 Carcass Analysis………………………………………..………………………………38
3.5.9 Statistical Analysis……………….…………………………..…………………………38
CHAPTER FOUR………………………………………………..………….………….…39
4.0 RESULTS………………..………………..……..………….………………………….39
4.1 Proximate Analysis and Anti-nutritional Composition of Raw and Cooked
Sweet Potato Meal….. ………………..…………….………………….…………..…..39
4.2 Feeding Trials : Partial Replacement Value of Cooked Sweet Potato Meal
(CSPM) for Maize in Broiler Diets………………..……….…..……..46
4.2.1Experiment 1: Partial Replacement Value of Cooked Sweet Potato Meal (CSPM)
for Maize in Broiler Starter Diets (1-4weeks)…………..………..…….46
4.2.2 Experiment 2: Partial Replacement Value of Cooked Sweet Potato Meal for
Maize in Broiler Finisher Diets (5-8weeks)…..…………..……….…..48
4.2.3 Effect of Partial Replacement of Maize with CSPM on Carcass Characteristics of
Broiler Finishers (8 weeks of age)……..…………………..……………………….….50
4.2.4 Apparent Nutrient Digestibility of Broiler Chickens fed Varying Levels of CSPM
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(8 weeks of age)……………………….……………….………………………………53
4.2.5 Economic Analysis of Broiler Chickens fed Percent Replacement of CSPM
for Maize Diets…..……………………………………………..………………………..56
4.3 Feeding Trials : Comparative Performance of Broilers fed 3 Varieties
of CSPM at 10% Replacement for Maize…..…………….……………58
4.3.1 Experiment 3: Comparative Performance of Broiler Starter Chickens fed Three
Varieties of CSPM (1 – 4weeks) at 10% Replacement………………….58
4.3.2 Experiment 4: Comparative Performance of Broiler Finisher Chickens fed
Three Varieties of CSPM (5–8weeks) at 10% Replacement……………..60
4.3.3 Carcass Characteristics of Broiler Chickens fed Three Varieties of CSPM
at 10% Level of Replacement (8 weeks of age)..……..……………..…………..………62
4.3.4 Nutrient Digestibility of Broiler Chickens Fed three Varieties of CSPM
(8weeks of age)…………………………………………….…………………………….64
CHAPTER FIVE………………………………………..…..……………………………..67
5.0 DISCUSSION………………………………….…………………….…………….….67
5.1.1 Proximate Composition of Sweet Potato Meal (Raw and Cooked).……..……….…….67
5.1.2 Anti-nutritional Factors Composition in the Three Varieties of Sweet Sotato
Meal (Raw and Cooked)………………………………………………………………..68
5.2 Performance of Broiler Chicks to Dietary Replacement of Maize with
Cooked Sweet Potato Meal (1-4 weeks) ………………………………………..……….70
5.3.1 Performance of Broiler Finishers to Dietary Replacement of Maize
with Cooked Sweet Potato Meal (5-8weeks)………………………..………..…….…71
5.3.2 Effect of Partial Replacement of Maize with CSPM on Carcass Characteristics of
Broiler Finishers (8 weeks of age)……..………….…..………….……..………….….72
5.3.3 Apparent Nutrient Digestibility of Broilers fed Varying Levels of CSPM
(8 weeks of age)………………………….…………………………..………………..72
5.3.4 Economic Analysis of Broiler Chickens fed CSPM as Partial Replacement for
Maize………………………………………………….……………….………………..73
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5.4 Comparative Performance of Broiler Starter fed 3 Varieties of
CSPM (1- 4weeks) in Place of Maize at 10% Level of Replacement…………………….73
5.5 Comparative Performance of Broiler Finishers fed 3 Varieties of CSPM
(5–8weeks) in Place of Maize at 10% Level of Replacement……………………………..74
5.5.1 Carcass Characteristics of Broiler Chickens fed Three Varieties of CSPM at 10%
Level of Replacement (8 weeks of age)…….…………..………………………………74
5.5.2 Nutrient Digestibility of Broiler Chickens fed Three Varieties of CSPM
at 10% level of Replacement (8weeks of age)…………………….……………………75
CHAPTER SIX……………………………………………………………………….……76
6.0 SUMMARY, CONCLUSION AND RECOMMENDATIONS…………….…….76
6.1 Summary………………………………………………………………………………76
6.2 Conclusion………………………….……..………..…………………………….……77
6.3 Recommendations………………….………….………..……………………….…….77
REFERENCES….…….……………………………………………………………….……79
APPENDIX……………………………………..……………………………………………86
CHAPTER ONE
NTRODUCTION
Livestock play a very important role in the Nigerian economy contributing about 12.7% of the agricultural GDP (CBN, 1999). The Nigerian livestock population comprised of about 14 million cattle, 34.5 million goats, 22.1 million sheep, 114.3 million poultry, 0.9 million donkeys, 0.2 million horses, 0.09 million camels, 3.3 million cats, 1.7 million rabbits, 0.5 million guinea pigs, and 0.06 million giant rats (RIM, 1992). It is a common knowledge that meals without any piece of meat are a regular diet for a larger proportion of Nigerians. Nigerians consume less than 10g of protein per person per day out of which only about 3.2g is animal protein. This falls short of the FAO’s recommended daily intake of 30g per caput per day (Dafwang, 2006). The high cost of animal protein in developing countries is the major constraint militating against the availability of the much-needed high quality protein food for the low income people. An increase in the standard of living almost inevitably calls for an increase in demand for animal protein. This situation calls for the production of fast growing animals like poultry. (Balogun, et al., 2003).
As laudable as poultry is in bridging animal protein gap in Nigeria, the industry faces a lot of problems. The most important problem is sub-standard nutrition which needs urgent attention. This is because the production potential of birds depends mainly on the type of feed given (Egbewande, 2009). Good quality food is one of the reasons for livestock production, it involves the wise use of available feed ingredients in formulating a palatable, economical, and nutritionally balanced ration for livestock and poultry (Cole, 1966). Reduction in the cost of poultry feeds is by far the most important focus of researchers at least in the developing countries today (Oyedeji, et al., 2003). Ayuk and Essien (2009) observed that feed gulps more than 80% of the total cost of running any poultry enterprise.
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The keen competition between man and poultry for grains has been implicated in the rising cost of poultry production, (Ademosun and Esthiett, 1980 as sited in Oruwari et al., 2003). Unfortunately, the survival of the poultry industry is dependent on the availability of feedstuff, which are mainly components of human food. There is therefore need for the animal nutritionist to radically seek for alternatives to the inadequate and expensive conventional feedstuffs to forestall an impending serious food crisis. (Okah and Onwujiariri, 2010). The rising cost of maize necessitate a research for cheaper and locally available non-conventional energy feed stuff such as sweet potato (Ipomoea batatas LAM). Considering the fact that sweet potato (Ipomoea batatas LAM) is traditionally grown as staple crop in many developing countries like Nigeria, this makes it locally available and relatively cheap. Sweet potato is widely adapted to divers altitudes (up to 2000 M) and temperature conditions. It requires practically low cash inputs and minimal agronomical practices and it competes better with weeds than other root and tuber crops (Scott, 1995). Moreover, it has low anti-nutritional factors, low fibre, high nitrogen free extract and is highly palatable. It can be incorporated into the diet of monogastric animals as a source of energy without any detrimental effect on their health and performance, thereby reducing the cost of feeding. Sweet potato is capable of thriving and yielding well on poor soils and may be a saving grace for the poultry industry (Afolayan, 2010).
Sweet potato is one of the world’s most important food crops. Its main nutritional importance has been its starch content. However, sweet potato can also be a source of other nutritionally important dietary factors such as Vitamin A, Ascorbic acid, Thiamin, Riboflavin and Niacin (Dominguez, 1990). The few available reports agree that sweet potato can be incorporated into diets of chickens but should not be made the sole source of energy (Lee,1979; Lee, 1980; Winarno, 1982 and Tewe, 1991) as cited by in Afolayan, (2010).
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Carbohydrates generally make up 80 to 90% of the dry weight of sweet potato roots, however, the uncooked starch of the sweet potato is very resistant to hydrolysis by amylase but when cooked, its susceptibility to the enzymes increases. Thus, after cooking, the easily hydrolysable starch fraction of sweet potato is reported to increase from 4 to 55%. (Cerning – Beroard and Le Devidich, 1976). Arising from several reports highlighted, it is well established that reduction of feed cost is a major concern of poultry producers, therefore replacement of part of traditional corn diet with a lower-cost alternative feed stuff like cooked sweet potato meal requires the assessment not only of the poultry performance and carcass characteristics, but also the general acceptability by birds (Poste, 1990).
1.1 RESEARCH HYPOTHESIS Ho. Partial replacement of maize with CSPM in the diets of broiler chickens does not have any significant effect on nutrient retention and utilization by the birds. HA. Partial replacement of maize with CSPM in the diets of broiler chickens have significant effect on nutrient retention and utilization by the birds. Ho. There is no significant difference in nutrient retention and utilization by broiler chickens fed diets containing three common varieties of cooked sweet potato meal. HA. There is significant differences in nutrient retention and utilization by broiler chickens fed diets containing three common varieties of cooked sweet potato meal.
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1.2 OBJECTIVES OF THE STUDY To evaluate the effect of partial replacement of maize with CSPM on growth performance and nutrient digestibility of broiler chickens at starter and finisher phases of feeding.
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To investigate the effect of partial replacement of maize with CSPM on carcass yield of broiler chickens. To determine the optimum replacement level of maize with CSPM in broiler chicken diets. To compare the performance in nutrient digestibility and utilization of broiler chickens fed the three common varieties of CSPM. To determine the economics of partial replacement of maize with CSPM in broiler production.
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