Chemical anticoccidials have varying degrees of efficacy ranging from good to partial resistance, indicating its use should either be restricted or if possible be discontinued because in the near future development of resistance against these anticoccidial will be seen. Use of herbal products as an alternative to anticoccidial drugs may overcome the hazards caused by the chemical drugs. Generally, plant extracts do not have problem of resistance and broilers fed on herbal feed additives were accepted well by the consumer.
To date, Eimeria strains have gained resistance to all known coccidiostats, and new anticoccidials are unlikely to be developed, mainly because of strict legislative regulations on the use of feed drugs and growing concerns in the general population about the chemical residues in poultry products. Over the past years, the consumption of poultry meat has grown consistently, especially because it represents a fairly cheap source of food with lower production costs and accepted by all religions.
In addition, the compromised immune system and damaged intestinal passage becomes an easy target for secondary bacterial infections like Clostridium and Salmonella spp.
What is Coccidiosis?
Coccidiosis is a disease of the intestinal tract caused by the microscopic parasites called Eimeria protozoa. It is a single cell microscopic parasite which enters the chick's body through ingesting the parasite egg on the ground.
Coccidiosis is a parasitic disease caused by seven species of the genus Eimeria with different localizations within the intestinal tract of chickens. Eimeria acervulina, E. maxima and E. tenella are the most prevalent species in broilers in the intensive poultry management system.
Nature of coccidiosis
Coccidia have many different stages occurring either within the bird host, or in the outside environment. Within the host, the parasite develops into an oocyst, which is then excreted in the bird droppings. In the environment (typically in the litter) and under optimal temperature and moisture conditions, this oocyst then develops into a sporulated oocyst. The sporulated oocyst can infect other chickens and is very resilient, often surviving in the environment for several months. The prepatent period, which includes parasite development and sporulation, is approximately 4–7 days. Although many infections are subclinical, clinical signs of coccidiosis typically include diarrhea, decreased growth rate, decreased feed and water intake, decreased egg production, and increased mortality.
The parasite then multiplies in the intestine and is eventually expelled through the chick's feces. At this point, other chick will become infected when they accidentally ingest the Coccidia parasite. Chicks can all quickly get infected, most often spread by bringing infected hens into your flock, or by wild birds. The coccidia parasite is nearly impossible to completely eradicate.
Coccidia multiply best in warm, wet, dirty, overcrowded conditions and unfortunately nearly every chicken run contains trace amounts of the parasite. Fortunately, healthy adult chickens usually have strong enough immune systems that they won't be affected.
What are the Symptoms of Coccidiosis?
It normally manifests itself in chicks through the following symptoms:
Messy fluff around the vent
Yellowish, foamy diarrhea
Bloody droppings
Ruffled feathers
Poor appetite
Lethargy
Standing alone with closed eyes
Weight loss due to inability to absorb nutrients in food
Eventual death
Even if a chick survives, permanent intestinal tissue damage often occurs. Since a chicken's immune system is centered in the intestine, survivors could have a compromised immune system for life.
