The aquaculture sector is rapidly expanding in tandem with the growing population , as it is a critical industry for meeting the global demand for food supply needed to feed a population in the foreseeable future .

According to the Food and Agriculture Organisation of the United Nations ( FAO ), the global apparent consumption of aquatic food per capita continues to rise from 9.1 kg in 1961 to 20.6 kg per capita in 2021 , bringing the total global apparent consumption of aquatic animal foods in 2021 to 162.5 million tonnes ( FAO , 2024 ).

The increase in aquaculture production , however , presents significant challenges . Antibiotics have become increasingly important in maintaining high yields and protection against disease outbreaks , particularly in intensive farming systems .

While the use of antibiotics has undeniably led to increased aquaculture production and a consistent supply of seafood , it has also introduced a series of potentially harmful repercussions and risks to farmed animals , humans and the environment at large .

Overuse and improper application of antibiotics in aquaculture can contribute to the growth and spread of antibiotic resistance ( AR ), in which bacteria evolve to withstand the effects of these drugs .

RISE OF ANTIBIOTIC RESISTANCE

Antibiotics are commonly used in aquaculture for various purposes , including prophylactic measures to prevent infections , therapeutic treatment for sick animals , metaphylactic use to prevent anticipated diseases , and as growth promoters in which medications like oxytetracycline and florfenicol are given to animals to enhance the growth and feed conversion of aquatic organisms ( Alotaibi , 2023 ).

The global aquaculture industry is a significant consumer of antibiotics , with the Asia-Pacific region accounting for the majority ( 93.8

BY AESYAH SOFEA KHAIRURRUSHDI ROSLAN

and

NURHIDAYU AL-SAARI International Institute for Halal Research and Training ( INHART ), International Islamic University Malaysia ( IIUM )

per cent ) of this consumption . In 2017 , the estimated global antimicrobial use in aquaculture was 10,259 tonnes , projected to increase by 33 per cent to 13,600 tonnes by 2030 .

The four leading countries in antibiotic consumption are China , India , Indonesia , and Vietnam , reflecting their dominance in global aquaculture production . Antibiotics like quinolones , tetracyclines , amphenicols , and sulfonamides are the most used antimicrobials in aquaculture ( Schar et al ., 2020 ).

However , the widespread use of antibiotics creates selective pressure on the ecosystem , favouring the survival and proliferation of resistant bacteria . These resistant bacteria can be pathogenic or can transfer their resistance genes to other bacteria , leading to the spread of antibiotic resistance genes ( ARGs ) within microbial

communities of the aquaculture .

In many producing countries , the misuse and overuse of antibiotics were reported and have led to significant concerns , including the exclusion of fishery products from countries like China , India , Malaysia , Bangladesh , and Vietnam by the EU and the USA due to the presence of banned antibiotics such as chloramphenicol and nitrofuran ( Alotaibi , 2023 ).

Antibiotic resistance happens when bacteria or microorganisms retrieve the ability to endure the effects of antibiotics , or in other words , they no longer respond to these antimicrobial medicines , leading to their ineffectiveness in treating the disease .

This can occur via various mechanisms , including mutation and horizontal gene transfer ( HGT ). Random mutations in bacterial DNA , for instance , are making them susceptible to antibiotic resistance .

When a single bacterium mutates to become antibioticresistant , it can transmit that resistance to other bacteria within its surroundings through the transfer of genes ( HGT ).

Plasmids , or little circular bits of DNA , are one of the most common mediums for gene transfer among bacteria , with resistance genes being exchanged within and across farmed animals and humans by direct physical contact with the bacteria ( Darphorn et al ., 2021 ).

In this case , the conjugation process ( a process where bacteria connect and share a small piece of DNA that helps them pass on traits , like antibiotic resistance , making them stronger and better able to survive ) permits bacteria to share or exchange their antibiotic resistance genes with other genes present in their surroundings .

SILENT EPIDEMIC

Both ARGs ( Antibiotic Resistance Genes ) and ARB ( Antibiotic Resistance Bacteria ) are responsible for the silent epidemic that could impact a nation ’ s public health .

Residual antibiotics ( small amounts of antibiotics that remain in animals , like fish , after they have been treated with medication ) and resistant bacteria can enter surrounding aquatic environments through effluent discharge , water exchange , and the release of untreated wastewater .

This can lead to environmental contamination , allowing antibiotics in water bodies to persist , resulting in the selection of resistant bacteria . Aside from that , ARGs can move amongst bacteria in the environment , including those that are pathogenic ( harmful ) to humans and animals , adding to the global pool of antibiotic resistance .

Hence , when seafood is traded locally or internationally , these resistant bacteria and their associated resistance genes can be transferred to different regions , impacting local ecosystems and human health . The movement or transportation of seafood products can facilitate the dissemination of ARB through various pathways , including contaminated water , processing facilities , and distribution networks .

Furthermore , the use of antibiotics in aquaculture might result in residues entering the environment , promoting the selection and spread of resistant strains .

The impact of antibiotic use in aquaculture extends beyond the farming area , potentially posing a global public health challenge . As seafood is consumed worldwide , ARB from aquaculture can quickly spread across borders . Contributing factors include poor sanitation , misuse of antibiotics in fish feeds and treatments , lack of awareness , and environmental pressures that allow resistant strains to persist ( Alotaibi , 2023 ).

ARB from aquaculture can reach people via a variety of routes , including eating infected fish , cross-contamination during food processing , and direct contact with contaminated water . This can lead to infections that are difficult to treat , resulting in higher medical costs , more extended hospital stays , and increased mortality . People in direct contact with contaminated water , like fishermen and recreational users , are especially at risk .

The spread of ARGs from aquaculture to human pathogens makes illnesses more challenging to treat and manage , further straining public health systems .

STRATEGIES FOR MITIGATION

Many studies highlight the urgent need to scale up antibiotic resistance surveillance in aquaculture , particularly in Asia , where the