What are anticoccidial drugs?

Abstract

Coccidiosis, caused by Eimeria species parasites, has long been recognised as an economically significant disease of chickens. As the global chicken population continues to grow, and its contribution to food security intensifies, it is increasingly important to assess the impact of diseases that compromise chicken productivity and welfare. In 1999, Williams published one of the most comprehensive estimates for the cost of coccidiosis in chickens, featuring a com-partmentalised model for the costs of prophylaxis, treatment and losses, indicating a total cost in excess of £38 million in the United Kingdom (UK) in 1995. In the 25 years since this analysis the global chicken population has doubled and systems of chicken meat and egg production have advanced through improved nutrition, husbandry and selective breeding of chickens, and wider use of anticoccidial vaccines. Using data from industry representatives including veterinarians, farmers, production and health experts, we have updated the Williams model and estimate that coccidi-osis in chickens cost the UK £99.2 million in 2016 (range £73.0–£125.5 million). Applying the model to data from Brazil, Egypt, Guatemala, India, New Zealand, Nigeria and the United States resulted in estimates that, when extrapolated by geographical region, indicate a global cost of ~ £10.4 billion at 2016 prices (£7.7–£13.0 billion), equivalent to £0.16/chicken produced. Understanding the economic costs of livestock diseases can be advantageous, providing baselines to evaluate the impact of different husbandry systems and interventions. The updated cost of coccidiosis in chickens will inform debates on the value of chemoprophylaxis and development of novel anticoccidial vaccines.

Introduction

  • What are anticoccidials drugs?
  • Why are they essential for poultry health?
  • What is the best drug for coccidiosis?
  • How can producers responsibly manage their use?

Eimeria are protozoan parasites that can cause the enteric disease coccidiosis and can result in malabsorption, enteritis, and even death. Production of chickens, the hosts most affected economically, has increased, highlighting the disease’s importance to world food security.In a later study, the annual cost of coccidiosis in chickens was estimated to exceed £38 m in the UK at 1995 prices. Recent estimates, accounting for improvements in poultry husbandry and control measures like vaccination, put the UK’s 2016 cost at £99.2 million. This model’s global extrapolation of the disease’s estimated cost in 2016 of £10.4 billion underscores the disease’s substantial economic impact on the poultry industry. (Re-calculating the cost of coccidiosis in chickens) One of the most prevalent disease issues recognized by the poultry industry since the early 20th century is coccidiosis; this intestinal disease is caused by protozoan parasites of the genus Eimeria (Tyzzer, 1929). Coccidiosis exhibits itself as a diarrheal disease due to the destruction of a host’s enterocytes (Cox et al., 2010), which directly impacts chicken growth, mortality, and feed efficiency. It is estimated that Eimeria species cause a burden of US$ 13 billion in lost value annually to the global broiler industry due to loss of production (e.g. poorer feed conversion) and the costs associated with prevention strategies/technologies used to mitigate their effects (Williams, 1999; Dalloul and Lillehoj, 2006). (management of eimeria PHD pdf)

What are Anticoccidials drugs?

Anticoccidials are given in the feed to prevent disease and the economic loss often associated with subacute infection. Prophylactic use is preferred, because most of the damage occurs before signs become apparent and because drugs cannot completely stop an outbreak. Therapeutic treatments are usually given by water because of the logistical constraints on feed administration. Antibiotics and increased levels of vitamins A and K are sometimes used in the ration to improve rate of recovery and prevent secondary infections.

But overusing these drugs can lead to resistance. That’s why farmers rotate products or follow shuttle programs to slow it down. Most anticoccidials today kill parasites directly, though some only stop their growth. While birds can develop some natural immunity, this matters more in long-term flocks than short-cycle broilers. Before slaughter, drugs are pulled from feed to meet safety rules though this raises the risk of late infections. Even with all we know, the way some of these drugs work is still being studied. (Merck Veterinary Manual)

Mechanisms of Action Coccidiostats are classified into two groups: Lonophores

Ionophores (lasalocid, monensin, maduramicin, narasin, salinomycin, and semduramicin) They are usually administered from the first day of the birds’ life up to seven days before slaughter to guard against contracting the disease due to the omnipresence of oocysts. (Anim. Biosci.) made by good bacteria, function by upsetting the ion equilibrium within parasite cells. They flood the parasite’s system by either creating channels through the membrane or transporting ions like potassium, calcium, and sodium across it. Stress and energy depletion result from this overload, which ultimately causes cell death via rupture or apoptosis.

Synthetic Chemicals

Synthetic chemicals influence parasite metabolism by blocking their physiological processes. (Halofuginone, robenidine, diclazuril, decoquinate, nicarbazin, toltrazuril, clopidol, ethopabate, amprolium, sulfadimethoxine, and sulfaquinoxaline) (Anim. Biosci.) are some examples of synthetic compounds, and commercial formulas such as COCCIGUARD-TD leverage these actives for broad-spectrum control.. Each of them has a specific mechanism of action against coccidia. Compounds of this type are referred to as “chemicals” due to their chemical composition and operate by interfering with one or more stages of the parasite life cycle (Merck Veterinary Manual).

They have an effect against its intestinal phases as soon as it attacks the host gastrointestinal system, being potentially more effective in the case of serious infections, but over time, resistance may appear

Why are they essential for poultry health?

Vaccines, natural feed additives, preventive anticoccidial drugs, and the best handling practices. on farms are the most important things to do to stop and control coccidiosis.To protect the health and well-being of the birds and keep the production of high-quality chicken products at its highest level, poultry farms must use the right handling methods.One of the most important things to think about while running a chicken farm is that all workers should get thorough training on how to handle chickens. This includes knowing how birds act, using safe ways to raise and carry them, and stressing gentle handling to lower stress.(Anim. Biosci.) 

 

Benefits of preventive anticoccidial usage include:

  • Improve poultry health and welfare.
  • Steady production and lower losses for Improved economic stability.
  • Keeping poultry production at a high level contributes to global food security.

What is the Best Drug for Coccidiosis?

There isn’t a one-fit-all anticoccidial in chickens, because the choice depends on the production goals, patterns of resistance, and disease severity. Ionophores, such as monensin and salinomycin, are best to administer in the case of commercial broiler performance. Vaccines are applied directly (as a gel feed or in water), topically (sprayed to the eye), or in hatcheries where chickens are raised. However, effective application may be limited by the amount of entailing cost with untapped labor and expense (Anim. Biosci., 2021). For a targeted treatment, toltrazuril (Baycox®, e.g.) is highly effective with activity against intracellular life cycles of Eimeria. Another vital product, COCCIGUARD-TD, has a broad spectrum with a sufficient margin of safety that has compatibility with standard anticoccidial programs. Meanwhile, a dependable choice remains amprolium, especially in layers, because it has negligible residues risk and is approved with no egg withdrawal (Merck Veterinary Manual). To gain productivity, rotation or combining the drugs is a common practice to keep them effective and prevent risk of resistance in the future.

How can producers responsibly manage their use?

Inappropriate or overuse of anticoccidials can lead to the rapid development of resistance. The following are suggested best practices to reduce resistance:

  • Programs that rotate and shuttle: Anticoccidial medications should be alternated frequently to preserve their efficacy.
  • Litter management includes maintaining appropriate stocking densities, controlling moisture, and ensuring adequate ventilation.
  • Vaccination: Using live, attenuated vaccines to build immunity without using too many drugs.
  • Frequent monitoring: To quickly detect and treat resistance, routine evaluations like oocyst counts and lesion scoring are performed.
  • Respect for withdrawal periods: Making sure that the suggested time frames for product safety are strictly followed.
  • The use of natural products, such as oregano essential oil, as supplementary measures to support gut health is known as phytogenic additives. However, current research suggests that these products cannot completely replace conventional anticoccidial medications (Hasan Aksit, 2016).

By including these methods of administration, anticoccidials’ long-term effectiveness is maintained, protecting consumer trust and poultry health.

Key Points

  • Coccidiosis is a disease of young animals and is characterized by diarrhea and weight loss. 
  • Coccidia are species specific, so cross infection is not seen. 
  • Diagnosis is via fecal flotation or postmortem examination of tissues of affected birds. 
  • Prevention of the disease is key, using various anticoccidial drugs and/or vaccination.