Prevalence of and Awareness of the Risks Associated with Antimicrobial Drug Residues in Edible Tissues of Cattle and Pigs in Enugu State, Nigeria.
Abstract
This study was aimed at determining the prevalence of and awareness of health risks associated with antimicrobial residues (AMRs) in edible tissues of cattle and pigs slaughtered for human consumption in Enugu State.
In the first phase, the awareness of public health problems associated with consumption of animal tissues containing AMRs and compliance to specified withdrawal period (WP) by livestock farmers and veterinary practitioners were determined.
This was carried out using a total of 200 copies of structured questionnaire designed to obtain information on the status of antimicrobial drug use, observance of WP and awareness of public health problems associated with consumption of animal products containing AMRs.
A minimum of sixty (60) copies of the questionnaire were distributed to willing respondents in each of the three senatorial zones of the state.
One hundred and eighty-two (182) copies of completed questionnaire were recovered and the responses collated and analyzed.
The second phase of the study which was the determination of the prevalence of AMRs in edible tissues (kidney, liver and muscle) of cattle and pigs in the study area was carried out using Premi® test kit.
A total of 285 tissue samples (180 from cattle and 105 from pigs) were randomly collected from animals slaughtered in Nsukka, Akwata and 9th Mile slaughter houses.
Chi-square (χ2) test of independence was used to determine the strength of association between educational level of the respondents and observance of withdrawal period, and awareness of public health risks associated with consumption of animal products containing AMRs.
Table Of Contents
Title page i
Certification ii
Dedication iii
Acknowledgements iv
Table of contents vi
List of tables vii
List of figures and plates vii
Appendices viii
Abstract ix
CHAPTER ONE: Introduction
- Background of study 1
- Statement of problem 4
- Research questions 6
- Objectives of study 6
- Research hypotheses 7
- Scope of study 8
CHAPTER TWO: Literature review
- Definition of terms 9
- Antimicrobial agents 9
- Antimicrobial residues 9
- Unintentional residues 10
- Tolerance levels or maximum residue limits (MRLs) 11
- Acceptable daily intake (ADI) 13
- Violative or illegal residues 14
- Extra label use of drug 14
- Limits of detection (LOD) 15
- Withdrawal period 16
- Antimicrobials 18
- History of antimicrobials 18
- Use of antimicrobials in food animals 19
- Tetracyclines 21
- Betalactams 22
- Aminoglycosides 23
- Quinolones 23
- Amphenicols 24
- Sulphonamides 25
- Regulation of agricultural use of antimicrobials in Nigeria 25
- Antimicrobial residues monitoring and surveillance in Nigeria 26
- Antimicrobial resistance 28
- Effects of cooking or cooling on antimicrobial residues in meat 30
- Antimicrobial residue detection in animal products 31
- Microbiological methods 32
2.6.1.2 Limitations of microbiological methods 32
- Immunochemical methods 33
- Physico-chemical methods 33
- The choice of Premi® Test kit 33
- The principle behind Premi® Test 35
- Prevalence of antimicrobial residues in animal products in Nigeria 35
- Public health hazards of antimicrobial residues in animal products 36
- Antimicrobial drug resistance 36
- Allergic reactions 37
- Carcinogenic effect- 38
- Mutagenic effect 38
- Teratogenic effect 39
- Bone marrow depression 39
CHAPTER THREE: Materials and methods
- The study area 40
- The study design 41
- Questionnaire survey and interview 41
3.2. Experimental study 42
- Cross sectional study 43
- Sample population 43
- Sample size determination 43
- Sampling area selection 44
- Sampling method for sample collection 44
- Processing and screening of meat samples for antimicrobial residues 45
- The principle behind Premi® Test 46
- Interpretation of Premi® Test results 46
- Data presentation 46
- Data analysis 46
CHAPTER FOUR: Results
- Result of the questionnaire survey 48
- 1.1 Socio-economic characteristics of livestock farmers———48
- Status of antimicrobial drug use in food animals———- 49
- Awareness of health risks associated with the consumption of AMRs in animal tissues— 49
- Knowledge of withdrawal periods among the respondents——-50
- Observance of withdrawal period 50
- Result of the experimental study 50
- Result of the cross sectional study 51 4.3.1 Prevalence of antimicrobial residues in cattle and pigs 51
- Organ distribution of antimicrobial residues in cattle—51
- Organ distribution of AMRs in pigs 51
CHAPTER FIVE: Discussion, Conclusion, and Recommendations
5.5 Discussion 62
- Questionnaire survey 62
- Cross-sectional study 65
- Conclusion 68
- Recommendations 68
- References 69
Introduction
Background Of Study
Antimicrobials are agents that act against microorganisms either by inhibiting their growth and multiplication or by complete destruction through various mechanisms of actions (Brander et al., 1993; Guardabassi and Kruse, 2008).
Antimicrobials are used in farm animals for 3 main purposes: therapy, prophylaxis and growth enhancement (Gutafson and Bowen, 1997).
These agents are used extensively in veterinary practice in Nigeria to prevent or control infectious diseases, to minimize post surgical infections and as growth enhancer by incorporation in feed at sub-therapeutic doses (Kabir et al., 2002).
Gains made in food production capacity in many parts of the world, in the past decades, would not have been possible if not for the ability of antimicrobials to contain the threats of diseases to animals (WHO, 1997).
Antimicrobials seem to be very important not just for sustainable livestock production but in the control of some zoonoses.
Guardabassi and Kruse (2008), are of the opinion that one of the major benefit to public health in the proper use of antimicrobials in animals, is the ability of these drugs to combat pathogens in animal transmissible to humans by direct contact, consumption of contaminated animal products or proliferation of these zoonotic pathogens into the environment.
Despite the gains in food animal production capacity and zoonoses control due to antimicrobial drug use in animals, the administration of these drugs in food animals is not without possible health risks especially when regulations guiding veterinary drug use are not complied with (Vandenberge et al., 2011).
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