What’s lurking in your chicken dinner?

In West Midnapore, West Bengal, Joymalya Halder manages a one-acre poultry farm, raising 14,000 broiler chickens five times a year. Each flock matures in just 38 to 42 days under tightly controlled conditions. The process involves three rounds of vaccinations and strict temperature regulation to ensure the birds grow optimally.

“Poultry birds are very susceptible to temperature changes. If they catch the flu—signalled by specific noises—an antibiotic is administered to prevent mortality,” said Halder.

But there’s a catch. “While antibiotics reduce mortality, they impact weight gain. Birds don’t eat as much after receiving antibiotics, which leads to losses,” he added.

Halder recalled a particularly challenging episode with a batch of 3,000 birds. “If one bird falls sick, the disease can spread rapidly, affecting the entire flock. Even a small change in the Feed Conversion Ratio (FCR) can cause big losses.”

An ideal FCR, Halder said, is 1.5. This means a bird should weigh 1 kg after consuming 1.5 kg of feed. But fluctuations in market prices can make or break a farmer’s bottom line. “Right now, raising a bird costs Rs 95 per kg. If the market price is between Rs 100 and Rs 110, we’re safe. But if it drops to Rs 88, we incur a loss of Rs 7 per kg. For 14,000 birds, that’s Rs 98,000 gone,” he said.

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Boon or bane?

Since the 1940s, antibiotics have been used as growth promoters (AGPs) in animal farming to meet rising global meat demand. While the Bureau of Indian Standards (BIS) recommends avoiding AGPs in poultry feed, they remain readily available and widely used.

The implications are alarming. A joint study by Toxic Links and World Animal Protection uncovered high levels of antimicrobial resistance genes (ARGs) in poultry farms in Tamil Nadu and Andhra Pradesh. Samples revealed ARGs against 15 critical antibiotics in 11 out of 14 groundwater and poultry litter tests.

PK Patil, principal scientist at the Central Institute of Brackishwater Aquaculture, underscored the problem’s complexity. “The unscientific use of antibiotics accelerates antimicrobial resistance (AMR) in animals. To effectively address AMR, we need to tackle its root causes,” he says.

Patil’s research focuses on how antibiotics degrade in the environment, particularly in soil and water. He has observed a stark contrast between India and Northern Europe. “In Europe, antibiotics persist longer in the environment. But here, high temperatures and intense sunlight speed up their degradation,” he said.

Correct usage involves knowing which antibiotics to use, their dosages, duration, and administration methods. Education on the types, concentrations, and doses of antibiotics is crucial in India.

Still, the risks remain high. Misuse of antibiotics–especially those critical for human health–blurs the line between animal and human medicine. “Some antibiotics are important for humans, while others are meant for animals. It’s crucial not to mix them, as animal-specific antibiotics should not be used in humans and vice versa. However, this distinction is often overlooked, leading to potential misuse,” he added.

Patil also stressed the importance of understanding global and Indian antibiotic usage patterns. He called for a coordinated, national-level programme to establish clear guidelines for antibiotic use and monitor AMR trends continuously.

"Correct usage involves knowing which antibiotics to use, their dosages, duration, and administration methods. Education on the types, concentrations, and doses of antibiotics is crucial in India," he said.

Mapping AMR

A recent study by the Drug Safety Division of the Indian Council of Medical Research-National Institute of Nutrition (ICMR-NIN) in Hyderabad has revealed critical insights into antimicrobial resistance (AMR) in poultry. Researchers analysed AMR gene profiles from chicken farms in Kerala and Telangana, uncovering distinct resistance patterns.

Southern Kerala emerged as a hotspot, showing the highest concentration of AMR genes. The study collected chicken faeces samples from farms across Central and Southern India. Genetic material from these samples underwent whole genome sequencing, uncovering significant levels of gram-negative and anaerobic bacteria.

The findings highlighted regional differences. Southern India showed a greater abundance of AMR genes compared to Central India, with E. coli more commonly detected in the southernmost areas. Interestingly, the AMR profiles from these farms resembled patterns seen in poultry farms in the European Union (EU). However, researchers found no evidence of the mcr-1 gene in E. coli—a gene associated with resistance to colistin, a last-resort antibiotic for severe infections.

Also read: How our meat industry is feeding antibiotic resistance

Growing concerns

India is the world’s third-largest egg producer and fourth-largest chicken meat producer, with broiler production concentrated in Tamil Nadu, Andhra Pradesh, Maharashtra, Uttar Pradesh, and Telangana. This scale of production raises concerns about antibiotic residues in poultry products.

When laying hens receive antibiotics, traces of the drugs can build up in their eggs. After administration, antibiotics are absorbed in the chicken’s intestines and travel through the bloodstream to the ovaries and oviducts. Since the ovaries create the egg’s contents, residues are more likely to appear in the yolk and albumen.

Cooking methods such as boiling, steaming, frying, or microwaving can break down some antibiotic residues. However, research shows that boiling affects only certain drugs. This means that even when residues are undetectable, they may still pose health risks, making eggs potentially unsafe to eat.

By 2030, antimicrobial usage in India is expected to exceed the global average by 40%. In 2021 alone, the country administered 2,160 tonnes of antimicrobials to livestock. Vijay Pal Singh, principal technical officer (Veterinary) at CSIR-Institute of Genomics and Integrative Biology, emphasised the need to prioritise human-critical antibiotics.

“These are antibiotics that are considered ‘last-resort’--highly effective and essential for human health. We should ensure these antibiotics are reserved exclusively for human use,” he said.

The PM effect

Shivaji Bhattacharya, a wildlife expert and former deputy director of Animal Resource Development at the Government of West Bengal, noted that antimicrobial resistance would continue to develop even without antibiotic use.

“One cause of AMR is PM2.5, and another is the pharmaceutical industry. Untreated effluents released during antibiotic production pollute air and water, worsening the problem. As the antibiotics industry grows, so does this issue,” he said.

Research conducted across 116 countries between 2000 and 2018 revealed strong links between PM2.5 pollution and antibiotic resistance. These links have strengthened over time. According to The Lancet, PM2.5-related AMR caused an estimated 0.48 million premature deaths in 2018, resulting in 18.2 million years of life lost and an economic impact of USD 395 billion annually.

As the poultry industry continues to grow, striking a balance between productivity and sustainability is crucial. The cost of inaction may prove too high for both farmers and public health.

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