Effect of Season on Aflatoxins Load of Selected Feedstuffs for Pigs in the Humid Tropics.
ABSTRACT
The effect of seasons on aflatoxins loads of selected pig’s feedstuffs in the humid tropics was investigated, the feedstuffs sampled were cassava peels, bambara nut waste, palm kernel cake and brewer spent grains. The study lasted for thirty-two weeks.
These feedstuffs were collected in two piggery farms in each of the six LGAs that make up Nsukka zone of Enugu State, in both dry and rainy seasons. The collected feedstuffsamples were analyzed in the laboratory for aflatoxins concentration levels using AOAC method of thin-layer chromatography (TLC)with some modifications.
Data were collected from the aflatoxins laboratory analysis of these feedstuffs and with a structured questionnaire. The results of this study indicated the presence of aflatoxins in all the sampled feedstuffs, however the lowest concentration of aflatoxins which is 0.011ppb is obtained in cassava peels and bambara nut wastes while the highest concentration of aflatoxins obtained is 0.055ppb in brewer spent grains.
These values are within the tolerance limit in Nigeria for total aflatoxins (B1+B2+G1+G2),which is 20ppb.The obtained aflatoxins levels are within range and poses less risk to pigs and pork consumers.
The results also shows that there were no significant difference (P > 0.05) on the aflatoxins concentration levels of the feedstuffs at their sources, across the piggery farm locations, in the season and source of feeds interactions, season and the piggery farm locations interactions, as well as season and feedstuffs interactions.
However the main effect of seasonon aflatoxins level which is 0.022ppb and 0.044ppb in the dry and rainy seasonrespectively were highly significant (P < 0.01).Also the main effect of aflatoxins of the feedstuffs were highly significant (P < 0.01) except in brewer spent grains were it is significant (P < 0.05).
It follows that the aflatoxins levels according to season in the comparison between the source of feedstuffs and the piggery farm locations for the sampled feedstuffs were highly significant (P< 0.01) especially in the rainy season, except bambara nut wastewhich is highly significant (P< 0.01) in the dry season.
TABLE OF CONTENT
Title Page … … … … … … … … … …i
Certification … … … … … … … … … …ii
Dedication … … … … … … … …. … …iii
Acknowledgement … … … … … … …. … …iv
Abstract … … … … … … … … … …v
Table of Contentss … … … … … … … … …vi
List of Tables … … … … … … … … …xi
List of Figures … … … … … … … … … ….xii
Chapter One
1.0 Introduction
1.1 Background of the study … … … … … … …….1
1.2 Statement of Problem … … … … … … …….4
1.3 Objectives of the study … … … … … … …. ……5
1.4 Justification of the study … … … … … … ……6
Chapter Two
2.0 Literature Review
2.1 Brief History of Aflatoxins … … … … … … … ……7
2.2 Natural Occurrence of Aflatoxins … … … … … ……8
2.3 Mycotoxins and Its Effects…. … … … … … …..10
2.4 Chemical Reactions of Aflatoxins … … … … … ….12
2.4.1. Heat …. … … … … … … … … ….12
2.4.2 Alkalis … … … … … … … … ….12
2.4.3 Acids … … … … … … … … … ….14
2.4.4 Oxidizing Agents … …. ….. … … … … ….14
2.4.5 Reduction … ….. …… … … … … …14
2.5 Chemical Structure of the Different Types of Aflatoxins … …15
2.6 Aflatoxin B1 Pathways … … … … … … …16
2.7 Metabolism of Aflatoxins … … … … … …16
2.7.1 Bio-activation … … … … … … … …16
2.7.2 Conjugation… … … … … … … … …16
2.7.3 Deconjugation … … … … … … … …17
2.7.4 Aflatoxins Units and its Conversion … …. … … …17
2.8 Factors that favours Mould Growth and Development … …18
2.9 Clinical Signs/Symptoms of Aflatoxicosis in Pigs… … … …18
2.9.1 Acute Aflatoxicosis… … … … … … …19
2.9.2 Chronic Aflatoxicosis … … … … … … …19
2.10 The Effects of Aflatoxins in Pigs … … … … …20
2.11 Aflatoxins Tolerance Levels and Action Limits in Animal Feeds …23
2.12 Aflatoxins and Climate Change… … … … … …27
2.13 Aflatoxins and its Economic Importance … … … …28
2.14 Aflatoxins Metabolism in Animals …. … … … …29
2.15 Methods of Aflatoxins Determination and Quantificationin Samples…. 30
2.16 AflatoxinsPrevention and Control Strategies…… … … ….32
2.17. Alternative Feedstuffs and their Uses in Pig Feeding … … …41
2.18 Cassava Peels Meal (CPM)…. …. … … … … …42
2.19.1 Nutritive Value of Cassava Roots/Peels … … … …44
2.19.2 Utilization ofCassava Peels as feedstuffs … … … ..… …45
2.19.3 Constraints to the Use of Cassava Meal/Peels as a feedstuff… … …47
2.20 Palm Kernel Cake (PKC)… … … … … … …48
2.20.1 Nutritive Value of Palm Kernel Cake as feedstuffs … … …49
2.20.2 Utilization of Palm Kernel Cake … … … … … …51
2.20.3 Constraints to the Use of Palm Kernel Cake … … … …52
2.21 Bambara Nut Waste (BNW)… … … … … … …53
2.21.1 Nutritive Value of Bambara Nut/Waste as feedstuff … … …54
2.21.2 Utilization of Bambara Nut /Waste .. … … … …56
2.22 Brewer’s Spent Grain (BSG)… … … … … …57
2.22.1 Nutritive Value of Brewer’s Spent Grains… … … … …58
2.22.2 Utilization of Brewer Spent Grains as feedstuff…… … … …61
2.22.3 Constraint to the Use of Brewer Spent Grains … … … …62
2.23 Brewer Yeast … … …. … … … … …63
2.23.1 Nutritive Value and utilization of Brewer Yeast in Livestock feeds… …63
2.24 Effect of High Content of Fibre in Pigs Diets … … … …65
2.25 Anti-nutritional factors in Non-conventional Feedstuffs …… …66
2.25.1 Classification of Anti-nutritional Factors (ANFs) … … …67
2.25.2 Factors Interfering with the Digestion and Utilization of Dietary
Proteins and Carbohydrates … … … … … …68
2.25.2.1 Tannins … … … … … … … …68
2.25.2.2 Saponins … … … … … … … …69
2.25.2.3 Trypsin or Protease Inhibitors…. … … … … …69
2.25.2.4 Haemagglutinins… … … … …. … … …70
2.6 Factors that Interfers with availability of Minerals … … …71
2.26.1 Phytates … … … … … … … …71
2.26.2 Oxalic Acid … … … … … … … …71
2.26.3 Glucosinolates… … … … … … … …71
2.26.4 Gossypol … … … … … … … …72
2.26.5 Phytoestrogens … … … … … … …72
2.26.6 Anti Vitamins … … … … … … … …72
2.26.7 Cynogens … … … … … … … …72
2.26.8 Lathyrogens … … … … … … … …73
2.26.9 Nitrates and Nitrite … … … … … … …73
2.26.10 Flatulence Factors … … … … … … …73
2.27 Pigs and its Characteristics … … … … … …73
2.28 Humid Tropics and its Characteristics … … … …74
Chapter Three
3.0 Materials and Methods
3.1 Location of the Study… … … … … … … … …76
3.2 Experimental Materials… … … … … … … … …76
3.3 Experimental Procedure… … … … … … … … …77
3.4 Sample Preparation … … … … … … … … …77
3.5 Procedure for Aflatoxins Determination and Quantification by (TLC)… …. …78
3.5.1 Apparatus… … … … … … … … … …78
3.5.2 Reagents… … … …. …. … … … … … …78
3.5.3 Procedure of AOAC Aflatoxins Analysis using TLC … … … … ….79
3.5.4 Method of Determination of Aflatoxins Concentration in Feedstuffs Samples … …81
3.5.5 Safety Issues… …. …. … … … … … … …81
3.6 Experimental Design… …. … …. …. …. … … …82
3.7 Data Collection… … … … … … … … … …82
3.8 Statistical Analysis … … … … … … … … …83
Chapter Four
4.0 Results and Discussion
4.1 Results and Discussion of Aflatoxins Laboratory Analysis of Pigs feedstuffs … …84
4.1.1: The results of the effect of source of feedstuffs on the aflatoxins levels of pig feedstuffs 84
4.1.2: The results of the effect of farm location on the aflatoxin levels of pig feedstuffs … 85
4.1.3: The results of the effect of season on the aflatoxins levels of pig feedstuffs …. 86
4.1.4: The results of the effect of feedtype on aflatoxins levels of pig feedstuffs …. …. 86
4.1.5: The results of the effect of season on aflatoxins levels of pig feedstuffs …. …. 87
4.1.6: The results of the effect of source and season on aflatoxins levels of pig feedstuff … 88
4.1.7: The results of the effect of feedstuff and season on aflatoxins levels of pig feedstuffs 89
4.1.8: The results of the effect of season and farm location on aflatoxins levels of feedstuffs 90
4.1.9: The results of the effect of source and farm location on aflatoxins levels of feedstuffs 91
4.2 Pig Farmers Responses and Discussions … … … … … … 95
4.2.1 Marital status … …. …. …. … … … … …. … 98
4.2.2 Educational Qualifications … …. … … … … … … 98
4.2.3 Gender… … … … … … … … … … … 98
4.2.4 Number of pigs reared in the farm … … … …. …. … … 99
4.2.5 Frequency of sourcing pigs’ feedstuffs …. … …. …. … …. 99
4.2.6 Quantity of feedstuffs purchased in kg/tons …. … …. …. … …. 100
4.2.7 How these feedstuffs are stored in the piggery farms…. …. …. … …. 100
4.2.8 Susceptibility of pig breeds to mould contaminated feedstuffs …. … …. 100
4.2.9 Ingredients added to the feedstuffs to improve its nutrient availability … …. 101
4.2.10 Mould incidence/infestation of feedstuffs fed to pigs…. …. …. …. …. 101
4.2.11 Feedstuffs that develop moulds faster than others …. …. …. …. …. 101
4.2.12 How does these symptoms affect the pigs … …. …. …. …. …. 102
4.2.13 Feedstuffs used by pig farmers to feed pigs in their farms …. …. …. …. 103
4.2.14 Main source of feedstuffs from where the pig farmers procure feedstuffs …. …. 104
4.2.15 Signs and symptoms shown by pigs when fed mould contaminated feeds …. …. 105
4.2.16 Preventive measures adopted to reduce mould infestation of the feedstuffs …. …. 106
4.2.17 The season/ period of the year mould infestation of feedstuffs are prevalent …. 107
Chapter Five
5.0 Summary,Conclusion and Recommendation
5.1 Summary … … … … … … … … … …109
5.2 Conclusion… … … … … … … … … …110
5.3 Recommendations … …. … … … … … …110
References
Appendices
INTRODUCTION
The consumption of animal protein is very essential for meeting the protein requirement of man for normal growth and healthy development. The protein sources from animal origin are good sources of lysine and sulphur amino acids, which are lower in protein sources from plant origin (Omole, 1991).
The shortage of protein, particularly animal protein is prevalent in most parts of Africa where it is estimated that on the average 10 grams of animal protein is consumed per day compared to the recommended daily intake of 35 grams (ILCA,1980; FAO, 1986).
The level of animal protein consumption was estimated at 8 grams per caput per day, this is about 20 grams less than the National Research Council of United States of America’s recommendation (Obioha, 1992; FAO, 1997).
Ogini (2001) stated that Nigeria, despite its vast land area of 9,237,680km2 , the greaterpercentage of her citizens of over 120 million are still battling with abject poverty and hunger. Atsu (2002) reported that there is inadequate intake of animal protein in Nigeria.
The high cost of feeds and feed ingredients, especially the conventional energy and protein feed sources such as maize, wheat, sorghum, soybean cake, groundnut cake and fish meal were as a result of the stiff competition between human consumers for food, for livestock feeds/feeding and industrial raw materials e.g. cereal grains for baby food formulas and biofuel production, especially maize (Agbede et al., 2002; Adegbola and Asaolu, 2008).
REFERENCES
Abarca, M. L., Accensi, F., Bragulat, M. R, and Cabanes, F. J. (2001). Current Importance of Ochratoxin: A producing Aspergillus Spp. J. Food Prot. 3: 256 – 258.
Adam, C. (2000). Origin and Control of Mycotoxins : Kemin Europa NV Milling Flour and Feed Magazine.
Adegbola, A. A. and Asaolu, O. (2008). Preparation of Cassava Peels for use in small ruminant Production in Western Nigeria. Department of Animal Science, University of Ife, Ile-Ife, Nigeria.
Adegbola, T. A. and Oduozo, R. O. (1992). Nutrient Intake, Digestibility and Performance of Rabbits feed varying levels of fermented and unfermented Cassava Peel Meals. J. Animal Prod. 12: 41 – 47.
Adeleye, A. A. (1992). Physiological Responses of Pigs Fed Graded Levels of Cassava (Manihot esculenta crantz) Peel in Maize based Diet. Ph.D Thesis, University of Ibadan, Ibadan.
Adesehinwa, A. O. K. (2004). Growth Performance and Serum Metabolites of young Pigs fed Maize Offal as Energy Source. E. Afri. J. Life Sci. 5(2): 87- 96.
StudentsandScholarship Team.
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