Background and Objective: Chicken farming in Cameroon has increased with population growth, this has increased the use of antimicrobial and a rise in antimicrobial resistance (AMR). The aim of this study was to assess chicken farming practices and quantify antimicrobial us age. Materials and Methods: Across-sectional study was conducted in 120 chicken farms in four regions of Cameroon (Centre, Littoral, South and West). Data was analyzed using descriptive statistics. Association between variables was tested using chi-square. Differences were considered significant at p<0.05. Results: Approximately 60% of farmers in the four regions, had no formal training on chicken farming. Thirty three different veterinary drugs containing active substances varying between one and two were used in the 120 farms. In center region the usage of veterinary drugs was the highest, with oxytetracycline as the most used active substance followed by sulfadimidine. In the littoral region the farmers mostly used levamisole (8), sulfadimidine (5) and oxytetracycline (5). In the west region, levamisole is used by 10 farms, sulfadimidine and oxytetracycline by 7 farms and doxycycline by 6 farms. Relatively higher usage of antimicrobial agents per chicken per unit time was observed in all the farms. Conclusion: High antimicrobial usage (AMU), including use of critically important antimicrobials was observed at poultry farms in selected regions. A monitoring system should be established to control the prudent use of antimicrobials. Rules and regulations for farmers should be implemented to reduce the AMU on priority basis.
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Poultry production is the best source of income generation and provides protein for human nutrition1. Recently, poultry industry, gains more attention and the demand is growing due to the higher cost of others animal protein sources2. In order to satisfy the growing demand, farmers should ensure the quality of the flock by reducing diseases incidence. However diseases constitute one of the main constraints in the poultry industry3. To control and prevent diseases occurrence during poultry farming, veterinary drugs are used. These drugs when misused can entered the food chain, thus leads to a contamination of chicken products4. The occurrence of veterinary drugs residue in chicken meat and eggs could have side effects (allergic reactions, toxicity, carcinogenic effects and change of natural micro flora of intestine) on consumers. These occurs when concentrations are over the maximum residue limits defined for veterinary drugs in edible animal tissues4,5. Previous studies reported the occurrence of veterinary drug residues in chicken products in India and Ghana6,7. In Cameroon, improper use of antibiotics by farmers as well as the occurrence of antibiotics residues in chicken meat and eggs has been reported1,8. This can lead to occurrence of antimicrobial resistance. Thus there is a need to assess the usage of veterinary drugs and farming practices in order to make hypothesis on occurrence of antimicrobial resistance. During the last avian influenza in 2016 several measures were taken to protect human and animalhealth9. Furthermore few studies in Cameroon have investigated the quantitative usage of veterinary drugs in chicken farming. Assessment of veterinary drugs usage and chicken farming practices are the first step in evaluating health risk for consumers7. The present study was designed to assess chicken farming practices and usage of veterinary drugs related to antimicrobial occurrence in some chicken farms in four regions of Cameroon.
MATERIALS AND METHODS
Study area: The present study was conducted in four regions of Cameroon, the Center, the Littoral, the West and the South Regions in Fig. 1. The Central region covers 68.926 km2 and is composed of rolling hills on a vast plain with a mean altitude of 700-800 m, with lowered mounds. The climate has two wet seasons. According to National Institute of Statistics, Cameroon10, the population density is low, with about 36 inhabitants/km2. The Littoral region is covering an area of 20.239 km2 and housing more than 2.202.340 inhabitants. The population density is 124 inhabitants per km2. The west region covers 13.872 km2 and is mountainous, marked by highlands with a mean altitude of 1600 m and narrow valleys with catchments separating them. The climate has a unimodal wet season. The population density is relatively high10, with about 143 inhabitants/km2. The south region covers an area of 47.110 km2, with a population of about 534.900 inhabitants and a density of 13.4 inhabitants per km2.
Study design and data collection: A cross-sectional study was conducted in four regions (Centre, Littoral, West and South) of Cameroon due to their high potential for chicken farming. Three clusters, each cluster representing 10 chicken farms, were selected in each region using a random start point. Farm owners or workers were briefed about the objective of the study and their consent was obtained before administration of the questionnaire. A structured questionnaire pre tested was used to collect data on veterinary drug usage and chicken farming practices. Farm owners or workers were asked to provide detailed information on various veterinary drugs in use within the last three months. Data on each veterinary drug administered were collected and used to quantify the total amount of active drug compound. Quantification of drug was done using weight indicators.
Calculation of antimicrobials consumption: The consumption of antimicrobials per farm was defined as animal treatment days per year (ATD/Y). This is similar to the standard unit for consumption of antimicrobials in humans (DDD/1000 days). ATD/Y was estimated base on two variables, the first in the numerator that was the summation of the number of treatment days for all broilers present during the year. The denominator was the sum of the number of birds present per day for the year. By dividing these numbers and multiplying by 365, we obtain the number of days in which antimicrobials were administered to broilers on a farm per year. An ATD/Y of 1 means that the animal in the population was exposed to an antimicrobial for one day per year (ESVAC).
Estimation of antimicrobial usage: The formula adapted by Carrique-Mas et al.12 with little modification was used to estimate usage in mg kg1 per week (Uwc milli grams). The weight of broilers after the growth period of 6 weeks was estimated to be 3 kg, while that of layers after 24 weeks was 2.5 kg. The estimation of antimicrobial usage was obtained by using the following equation:
|Ur||: Amount of each active antimicrobial ingredient (milligrams)|
|Np||: Number of used antimicrobial products|
|t||: Length of reporting period for that farm (weeks)|
|Nc||: Number of chicken present in the farm|
|W||: Weight of the chicken (kg)|
Data analysis: Data were analyzed using a computer software SPSS version 20.0 for windows. Descriptive statistics (frequency, mean and percentages) was used to analyze the data. The AMU at the farm was categorized into low and high usage based on a previous estimate (10.6 mg kg1) of Layers13. AMU less than 10.6 mg kg1 was termed as low, while usage above this cut-off value was considered as high. Chi-square was used to present the relationship between variables. The value of p<0.05 was considered as significant.
Characteristics of farmers and chicken farming practices: Table 1 shows the characteristics of farmers who participated in the present study. The poultry farmers in the four regions were mostly men. Male poultry farmers in the center were 85.71%, in the littoral were 100%, in the west were 93.33% and in the south region were 92 %and the total were 92.5%. Only 7.5% of the farmers were female. The majority of the farmers (72%) had no formal training on chicken production.
The highest percentage of trained farmers (57.14%) were found in the center region. The farms were categorize in three groups depending on the number of birds in the farm, small size farm contains <1000 birds, medium farms contain 1001-2000 birds and large farms contain >2000 birds. Majority of the large farms (26.6%) were found in the West region. Concerning their experience in chicken farming, 76 (63.63%) farmers have more than three years of experience, center (68.58%) and the west (76.66%) regions exhibit high number of experienced farmers.
In 75% of the farms the layer was raised followed by broilers (18%). Majority of farmers (85.83%) used veterinary drugs and antibiotics to prevent disease outbreak in the chicken farm with various reasons. Large number of farmers in the littoral (100%) and the west region (90%) used veterinary drugs and antibiotics. The mentioned reasons were therapeutic (2.10%), prophylactic (6.31%), both therapeutic and prophylactic (91.57%). These veterinary drugs were obtained from market (10.52 %), from veterinary shops (67.36%) and from mobile sellers (22.10%). In 77.8% chicken farms, owners declared not knowing or applying withdrawal periods and not respecting doses. Only 10.52% chicken farms were respecting withdrawal periods. Wood shaving is the type of liter used by the majority of the farmers (92.63%), which was generally changed monthly by 69 (72.63%) farmers.
Statistical analysis using cross-tabulation was performed to verify the relationship between variables. The results revealed that characteristics of farmers has a significant association with qualifications, experience and the size of the farms. Antibiotics usage, source of antibiotics and reasons for usage also had significant association with the good farming practices.
Consumption of veterinary drug in the four regions: A total of 33 different veterinary products containing one or two active ingredients were used in the 120 farms visited at the time of survey (Table 2). The twenty-two active ingredients found in the different products were belonged to 14 veterinary drug classes. The higher number of veterinary drugs and antibiotics was used in the center region. Oxytetracycline from the tetracycline class of antibiotics was the most used (20 farms) active substance followed by sulfadimidine (11 farms) from polymyxins class of antibiotics and levamisole (10 farms) from the class of antihelminthic. In the littoral region the farmers mostly used levamisole (8 farms), sulfadimidine (5 farms) and oxytetracycline (5 farms). In the west region, levamisole was used by 10 farms, sulfadimidine and oxytetracycline by 7 farms and doxycycline by 6 farms. The farmers in the south region were using tetracyclines (Oxytetracycline), antihelminthic (levamisole) and benzimidazoles (albendazole) classes of veterinary drugs.