Study reveals excessive use of antibiotics in poultry treatment

Hand holds syringe and chicken in background. Antibiotics, vaccination and testing on animals concept.


A new study warns that overuse of antibiotics in Tanzania’s poultry industry poses a serious health risk to consumers and leads to the emergence of antibiotic-resistant bacteria in the chicken itself.

Dar es Salaam. Overuse of antibiotics in Tanzania’s poultry industry poses a serious health risk to consumers and is causing chickens to develop antibiotic-resistant bacteria, a new study warns.

The study titled Determination of Sulfonamides and Residues in Liver Tissues of Broilers Marketed in Kinondoni and Ilala Townships, Dar es Salaam, Tanzania was conducted by Winstone Ulomi, Fauster Mgaya, Zuhura Kimera and Mecky Matee from the Department of Microbiology and Immunology Muhimbili University of Health and Allied Sciences (Muhas ).

Study details

A cross-sectional study aimed to determine the concentrations of sulfonamide and tetracycline residues in liver tissues of broilers sold in Dar es Salaam and whether the amounts detected were within legal and acceptable limits in food.

The study showed that all samples collected contained tetracycline residues, although 21.4 percent showed the existence of sulfonamide residues, and samples containing both sulfonamide residues and tetracycline residues made up 21.4 percent of the sample collected.

While the study confirmed sulfonamide concentrations to be within the maximum residue limit (MRL), 90.5 percent of the samples had tetracycline levels that exceeded the acceptable daily intake (ADI).

According to the study, samples that contained levels of tetracycline exceeding the maximum residue limit were 13.1 percent.

The report found that the issue is largely fueled by the use of antimicrobials in animal feed, which is linked to more intensive farming.

Consumption of animal products

Tanzania’s pork consumption is projected to rise to 170,000 tons by 2030 from the current 42,700 tons, similar estimates say the annual poultry industry will increase by 148 percent in 2030 from the current 37,200 tons.

Tetracycline, sulfonamides, penicillin, aminoglycosides, and macrolides are commonly used antibiotics in poultry farming in Tanzania.

However, it is reported that tetracycline (8,057,240 kg) is the most consumed antibiotic annually in poultry farms, followed by sulfonamides and trimethoprim (3,057,240 kg).

“The antibiotics mentioned are readily available in veterinary stores and retailers and are readily available without any prescription or restrictions being imposed,” reads part of the study.

He adds: “Most farmers have insufficient knowledge and inappropriate attitudes and practices regarding the judicious use of antibiotics, which pose serious health problems for humans and animals.”

What are antibiotics?

When Dr. Nickson Ng’umbi, a veterinarian asked, “Antibiotics are drugs that can work either by killing bacteria or by inhibiting the growth and reproduction of bacteria, allowing the animal’s immune system to fight infection more effectively. .”

According to Dr. Ng’umbi, there is no way veterinarians can dispense animal drugs intended for human use. He adds: “By the way, medicines for animals are always labeled ‘Not for human consumption'”.

The vet was of the opinion that the greater risk lies in using the wrong drug and the wrong dosage. This is a serious problem, farmers simply diagnose the infection and then try to treat it with human antibiotics.

Dr Ng’umbi, who also runs his own combined ruminant and poultry farm, explained that like humans, animals are vulnerable to bacterial infections, including pneumonia and skin infections, and that the infections can be treated with antibiotics.

He further noted that similar to humans, antibiotics are used in animals to treat, control and prevent disease. In addition, a prescription is required as there are practical considerations when administering antibiotics to large groups on a farm.

“I have seen most of the farmers in WhatsApp groups asking for a solution, after discovering bacterial infections in their poultry, then a non-veterinarian farmer suggested a certain remedy. In reality, the diagnosis may not be correct as the antibiotics suggested, but the farmer will proceed and buy the same,” he reminded.

He added that: “Honestly, without effective antibiotics, it’s really a disaster, the bacteria cannot be kept under control, which will lead to terrible and fatal infections. So we have to involve a trained vet as without them, then we’re done.”

He therefore called on those involved in veterinary practice to conscientiously perform their duties and adhere to the ethical and moral principles that govern their profession.

The practitioner added: “And veterinary medicines should not be sold to a customer unless they present the appropriate prescription from a general practitioner.”

Lack of information

Dr. Hadija Suleiman, a doctor at Agape Polyclinic based in Dar es Salaam, explained that although antimicrobials are widely used in Tanzania, there is no information regarding quantitative use.

“In fact, the weak regulatory framework in Tanzania means that the use of antimicrobials in livestock production is not regulated, which contributes to antibiotic resistance, and I agree that the lack of basic knowledge about the concept of drug resistance among livestock and poultry farmers has exacerbated this problem . ” she remarked.

In addition, Dr. Suleiman explained that public health concerns arise when an animal or human illness is caused by bacteria that are resistant to so many antibiotics that a veterinarian or doctor cannot treat the patient with an antibiotic that will be effective.

According to her, all infections are potentially treatable if the etiological agents are sensitive to antimicrobial agents, but on the other hand, there is clear evidence of adverse human health consequences due to resistant organisms resulting from the inhumane use of antimicrobials.

How breeders get information

Mrs. Anita Jumanne, a poultry farmer based in Ubung, admitted that she used human-related drugs to treat her chickens because they were not only readily available but also affordable.

She noted, “I am a member of several WhatsApp groups for poultry farmers, that’s where I got this knowledge from. My chickens had what I recognized as fowl cholera. I just asked and an experienced farmer advised me to use azithromycin, which actually gave me good results.’

The single mother of two said she started raising chickens in her backyard just for domestic consumption until she developed an interest in commercial use and knowing nothing about it,but WhatsApp groups have helped her and that her business is doing great.

Asked if there were any problems arising from the use of human drugs for treatment on her poultry farm, Mrs Jumanne said: “I don’t see any problem. This seems to be the practice of many farmers, it was recommended to me and I found it useful. Maybe if we are told it is harmful, but no one has come forward to tell us. Most breeders use them.”

Generic versions of drugs

But Dr Michael Bihari, a medical practitioner, said many of the animal drugs were generic versions of human drugs but confirmed that it was unethical for a veterinarian to prescribe human drugs to animals or poultry or vice versa.

“For example,” he said, “a veterinarian might prescribe prednisone for an animal with an inflammatory condition. It’s the same medicine that people can get with a prescription.”

However, according to him, animal medicines are different from those intended for humans. For example, medicines made for livestock are intended to be mixed with feed and may also contain harmful impurities.

Therefore, he said: “It is vitally important for government and all practitioners to reduce the overall use of these drugs, which can actually be achieved without significant negative impacts on the health or productivity of both humans and animals.

Consumer opinions

Poultry consumer Neema Mhando said: “I never knew about it but because of their price I usually suspect that I am buying unhealthy chickens but I have no proof, the government has to protect us, they should register all breeders just like the last census I guess the government knows all the farms.’

Media reports indicated that a number of effective pre-emptive interventions to reduce resistance have been documented, including banning non-therapeutic use in animal feed and enforcement of prescription-only policies.

Other measures include limiting the use of drugs considered critical to human health, monitoring use at farm level and providing advice to end users, and setting thresholds for resistant pathogens in food.

Reducing the use of antimicrobials requires collaboration between experts, regulators and manufacturers, and integrated monitoring of the effects of interventions is necessary, which can be facilitated by the establishment of a coordinating body.

WHO, FAO guidelines

The Codex Alimentarius Commission (CAC) under WHO and FAO is said to have issued recommendations that should be implemented by all countries as a code of practice to minimize and limit antimicrobial resistance (CAC 2005).

It provides guidance on the responsibilities of regulators, the veterinary pharmaceutical industry, veterinarians and wholesale and retail distributors and manufacturers to ensure that antimicrobials are prescription only.

Among other things, the Code affirms that only drugs that are effective and have well-established dosages should be approved, programs to monitor drug use and resistance should be established, research should be encouraged, and all unused drugs should be collected and disposed of.


Please enter your comment!
Please enter your name here