Abstract: Objective: The objectives of this study were to survey for antimicrobial usage and to assess the antibiotic used pattern among poultry layer farmers in Maiduguri Metropolis Borno state Nigeria. Methodology: Multistage sampling technique was used together with structured interviewer questionnaire. Coordinates of each farm selected was recorded and map showing spatial distribution of randomly selected farm was constructed. Data were analyzed using Statistical Package for social science. Results: The result indicated that the majority of the farmers 30 (85.7%) admitted the use of antibiotic for disease prevention, 29 (82.9%) of the farmers were not aware of antibiotic residue in table eggs and 34 (97.1%) of the farmers were not aware of public health effect of antibiotic residue. Conclusion: It was deduced that there is indiscriminate use of most antibiotics in layer farms in Maiduguri Metropolis, There is poor knowledge of drug withdrawal period by farmers and poor awareness on passage of antibiotics from hen to eggs and its public health significance. Prohibited antibiotics for use in food producing animals such as nitrofurans, chloramphenicol and unapproved antibiotic for use in laying hens such as sulfonamide, doxycycline, streptomycin, gentamycin and ampicillin are very much in use in the study area.
INTRODUCTION
Antibiotics are chemical substances derived from biological sources or by chemical synthesis in the laboratory and they are able to kill or inhibit the growth of microorganisms1. Antibiotics are administered parentally, orally or topically2. Antibiotics are classified according to their effects (bactericidal or bacteriostatic) and also according to their range of efficacy (narrow or broad spectrum) or based on their mode of action (inhibitors of cell wall synthesis, inhibitors of protein synthesis, inhibitors of membrane function, anti-metabolites and inhibitors of nucleic acid synthesis)3.Antibiotics use in poultry farming started over a century for prevention, treatment of bacterial infection and growth promotion2,4,5. In layer hens, antibiotics are only used to treat and prevent bacterial infections6.Currently, majority of all food-producing animals receive medication for part or most of their lives7. Over the years the problem of antibiotic residue in food producing animals and their effect on human health has been a major concern5.The residue in chicken eggs are of concern because few drugs are label for used in laying hens even though several medications are approved for other classes of poultry production8,9.The overall relationship between antimicrobial used in food animals and resistance have been established10. Self-medication with antibiotics, use of human antibiotics in food animals and non-regulated prescriptions are the most common causes of residue and may have contributed to antibiotic resistance scourge in the poultry industry in Nigeria11. Geidam et al.12, reported in Maiduguri that antibiotics are freely marketed without veterinary prescription with tetracycline being the commonly abused antibiotic by poultry farmers. Layer farming as an entity in Maiduguri Metropolis Borno state of Nigeria have not been surveyed with regards to antibiotic usage. According to Codex Alimentarius Commission very few drugs are approved for used in laying hens and that prompted the need to assess the pattern of antimicrobial used among layer farmers in Maiduguri Metropolis, Borno state of Nigeria.
MATERIALS AND METHODS
Study area: This study was conducted in Maiduguri Metropolis the capital of Borno state in the North Eastern part of Nigeria in the month of January, 2016. It is the largest city in the North Eastern part of country13. The city is bounded in the North by Jere Local Government Area, in the West, South and South-West by Konduga Local Government Area, in the North-West by Mafa Local Government Area (Fig. 1)14. It has an altitude of about 300 m above sea level. Its geographical coordinates are 11°50’ 42" North and 13°09’ 36" East. The climate of Maiduguri is characterized by a long dry season with high evaporation rate from October-May and a short wet season for the remaining part of the year. However the native of the city identify four seasons. Crop production and livestock farming are the predominant occupation of the people15. Poultry layer production is a profitable business in Maiduguri Metropolis15.
Study design: Multi stage sampling method was used in selecting layer farms for questionnaire survey.
Maiduguri metropolis is divided into 4 major areas by Borno state water board namely Bolori, Gwange, Kyarimi Park and Shehuri North16. In this study, these areas were taken as the primary sampling units. In each area mention above 50% of sub areas were selected and sampled as secondary sampling units. Fifty percent of laying poultry farms within each secondary sampling unit were randomly sampled and taken as tertiary sampling units. Geographical coordinates of the sampled areas were taken and recorded. A spatial distribution analysis of the layer farm sampled were constructed (Fig. 1).
Questionnaire survey: Structured interviewer administered questionnaire was designed and administered to 35 randomly selected layer poultry farmers for the purpose of collecting information on the use of antimicrobials, awareness of withdrawal period, awareness of antibiotic residue in table eggs and awareness of any known health effect of antibiotic residue to public health. Empty sachet and bottles of used antimicrobial drugs were collected and recorded.
Statistical analysis: Data were analysed using Statistical Package Social Science Version 21. Descriptive statistic and Chi-square at 95% confidence interval was used to determine the relationship between variables at p value <0.005.
RESULTS
Total of 35 layer poultry farmers were interviewed, 28 (80%) of the respondents have tertiary education, 5 (14.3%), 2 (5.7%) have secondary and informal education, respectively (Table 1). Majority of the farmers are small scale peasants (94.3%) having equal or less than 500 birds in their farms. Most of the interviewed participants (85.7%) acknowledged that they often apply antibiotics for prevention of diseases. 71.4% farmers were aware of drug withdrawal period, 29 (82.9%) of them were not aware of antibiotic residue in table eggs and 97.1% were not aware of the public health importance of the residue.
| Fig. 1: | Map showing spatial distribution of sampled farms in Maiduguri Metropolis, Nigeria |
There is significance (p = 0.0004) association between level of education and awareness of public health implication of the residue.
DISCUSSION
Majority (85.7%) of the layer farmers in Maiduguri Metropolis use antibiotic for prevention of disease in their farms. The extensive use of antibiotic by the farmers in the study area might not be unconnected with the lack of knowledge on biosecurity mostly attributed to small scale poultry farmers in the study area. The same finding was reported by Omeiza et al.17, which state that small scale farmers used drug more often due to frequent experiences of poultry diseases as a result of poor biosecurity. Other investigators in Nigeria, Sudan and Tanzania have findings that are different from the result of this work, who attributed the extensive antibiotic usage to large scale layer production farming18-20. Flake and Ashitey21 had also noted that poultry farmers adopted antibiotics as preventive medication to compensate for biosecurity measures. High prophylactic use of antibiotic was reported in Nigeria17,22, Sudan23, Tanzania24 and Uganda25.
The study also revealed that despite strict observance of vaccination by majority of the farmers (82.9%), greater percentage of the farms (91.4%) had history of disease outbreaks which might be as a result of vaccine failure and/or poor management. Vaccine failure among poultry farmers was reported in Abia state26.
The survey also found that most farmers (71.4%) are aware of drug withdrawal period in food animals but do not observe it in their farms. One possible reason for failure to observe withdrawal period by farmers is lack of knowledge on the public health implications of drug residues in animal by-product and lack of knowledge regarding the passage of drugs from chicken to eggs. This finding is similar to reports of Sirdar et al.19 and Mubito et al.20, who reported 89 and 100% awareness in Sudan and Tanzania, respectively but it is important to note that Salman et al.23, reported awareness level of 36% in Sudan. In this study most farmers (82.9%) do not believe that drugs can pass from chicken to eggs and 97% are not aware of any public health problem related to antibiotics residue. This is contrary to the finding of Fagbamila et al.18, who reported 87.1% awareness of antibiotic residue by poultry farmers in Jos which might not be unconnected with large scale layer production an attribute of farming in Jos Plateau state. In a similar finding in Sudan by Sirdar et al.19, eighty five (85%) of the farmers are not aware of antibiotic residue and its public health effects on human also the findings of Salman et al.23, in Sudan agree with the findings of this research with 94% of the farmers not aware of antibiotic residue in table eggs and its public health effects.
| Table 1: | Response to questionnaire survey on the use of antibiotics in layer farms in Maiduguri Metropolis, Borno sate, Nigeria |
The survey found that tylodox (tylosin and doxycycline) and neofuramycine plus (furazolidone, chloramphenicol, neomycine, erythromycine, oxytetracycline and streptomycine) are the most commonly used antibiotic by the farmers 51.4 and 34.3%, respectively. Table 2 and appendix. This may be attributed to availability of these antibiotics in most of the drug stores in the study area. The finding of Annan-Phrah et al.27, in Ghana indicated the popularity of tylodox usage among layer poultry farms. Among the ingredient of tylodox and neofuramycine (appendix), doxycycline and streptomycine are unapproved antimicrobials in laying hens while furazolidone and chloramphenicol are prohibited substance in food animals due to their long withdrawal period, carcinogenic and mutagenic effect6,28. The study also showed that tetracycline (68.1%) and aminoglycoside (45%) were the most popular classes of antibiotics used by layer farmers in the study area (Fig. 2). The popularity of tetracycline and aminoglycoside might be due to their affordable price and availability either as single parent drug or in combinations with different antimicrobial agents, vitamins and minerals. In a similar study by Geidam et al.12, in Maiduguri showed that tetracycline and aminoglycoside were the most popular classes of antibiotics used by poultry farmers.
| Fig. 2: | Classes of antibiotics used in layer chicken farms in Maiduguri Metropolis, Borno state, Nigeria |
| Table 2: | Types of antibiotics used and their approval status by Codex Alimentarius Commission(CAC) in laying hens in Maiduguri, Metropolis, Borno state Nigeria |
| *CAC: Codex alimentarius commission | |
Other investigators from different parts of Nigeria have also reported the popularity of tetracycline among layer farmers17,18,29-32.
The popularity of tetracycline in other countries among poultry industry was also reported in Tanzania24,33, Sudan19,23, Kenya34, Kuwait35 and Saudi Arabia36.
The study observed that antimicrobial agents that are prohibited for use in food-producing animals like nitrofurans (furazolidone, furaltadone, nitrofurazone and nitrofurantoin) and chloramphenicols were used in layer poultry farms in Maiduguri Metropolis which is similar to the report of Geidam et al.12, which confirmed the use of furazolidone by poultry farmers in Maiduguri, Adebowale et al.11, in Ogun state and Ezenduka et al.30, in Enugu State. While the use of chloramphenicol by poultry farmers was reported in Kaduna17. These antibiotics are prohibited within European (Commission Regulation 1995), USA, Codex Alimentarius Commission and Nigeria37 for administration in food producing animals due to their carcinogenic and mutagenic effects.
| Appendix: | Antibiotics in Use in Maiduguri metropolis trade names and their compositions |
The study also observed that unapproved antibiotics in laying hens such as sulfonamides, doxycycline, streptomycin, gentamycin and ampicillin were widely use in laying farms in the study area. This might not be unconnected with the lack of awareness among farmers and unqualified staff and poor regulation on the use of such agents.
CONCLUSION
From this study it was concluded that:
| • | There is small flock size (back yard) farm in Maiduguri with 94.3% of the farmers holding equal or less than 500 birds in their farms |
| • | There is poor knowledge of drug withdrawal by farmers and poor awareness on passage of antibiotics from chicken to eggs and its public health significance |
| • | Prohibited antibiotics for use in food producing animals such as nitrofurans, chloramphenicol and unapproved antibiotic for use in laying hens such as Sulfonamide, doxycycline, streptomycin, gentamycin and ampicillin are very much in use in the study area |
RECOMMENDATION
Based on the findings of the study the following recommendation should be put into practice:
| • | Farmer education on the use of antibiotics and its public health implication |
| • | Antibiotics being a prescription drug should not be freely sold to farmers over the counter |
| • | The established Veterinary Directorate in NAFDAC should ensure the control of importation and subsequent use of antibiotics prohibited for use in food animals |
SIGNIFICANCE STATEMENT
The study discover that prohibited antibiotics like nitrofurans and chloramphenicol are patronized by layer poultry farmers in their laying hens and this study help the researchers to quantify the residue level of nitrofurans, chloramphenicol and unapproved antibiotics like sulfonamide, gentamycin and doxycycline in commercial eggs meant for human consumption.