27/04/2022
COCCIDIOSIS IN POULTRY.
Coccidiosis is a realistic problem and one of the most important diseases of poultry worldwide. It is caused by a protozoan parasite known as Eimeria that invade the cells of the poultry intestine. Species of coccidia which commonly affect poultry are Eimeria tenella, E. acervulina, E. necatrix, E. maxima and E. brunetti. The disease is characterised by enteritis, diarrhoea and mortality. The bird develops reduced ability to absorb nutrients, which results in weight loss and eventually death. Subclinically, it is manifested by poor performance, impaired feed conversion, poor flock uniformity and poor growth. Coccidia can also damage the immune system and leave poultry more vulnerable to pathogens like Clostridium, Salmonella and E. coli.
HOW THE DISEASE IS CAUSED
Coccidiosis is caused by protozoan parasites of the Eimeria genus which are always present in the shed and farm environment.
Their reproductive form – the oocysts – are present in the birds’ droppings and from here they can be ingested.
Once in the chicken they attach to cells on the gut wall and reproduce in several cycles, and once these cycles are complete, oocyts will be excreted back into the litter, where they go through maturation (sporulation) and can once again be ingested by birds.
HOW IT AFFECTS THE BIRD
This cycle of ingestion, reproduction and shedding can severely damage the gut wall, hampering the absorption of nutrients.
As the coccidiosis parasites build up, birds will become distressed, stop absorbing nutrients and become sick.
Each reproduction cycle lasts for five-to-seven days, and this is why a coccidiosis problem presents around 21-28 days; it takes time for the disease to build up in numbers sufficient to damage the gut.
So it is important to catch an infection early and treat before it spreads.
A coccidiosis problem gone undetected can spread right across a flock, and cause a serious drop in feed conversion, health problems and, eventually, mortality.
It is important to remember that coccidiostats are not designed for treating sick birds; they are used prophylactically, to inhibit the development of the parasite and stop healthy birds from becoming sick.
DETECTION
As well as keeping an eye out for unhealthy looking litter, watery faeces or mucus is an obvious indicator that there are at least some unhealthy birds in the flock.
It means that the broiler is not eating, or its gut is unable to digest food properly. A drop in feed intake can be the next indicator that coccidiosis may be present.
