HEAL ▶▶▶TH
How to optimise your coccidiosis management
Coccidiosis is a hard nut to crack as the disease- causing protozoa has a complex life cycle and has a tendency to become insensitive to treatments. Thus, coccidiosis management requires attention and strategy. Tackling the Eimeria bug is a challenge and coccidiosis management needs constant tweaks, including attention to good overall bird health.
BY SHELBY RAMIREZ, DSM ANIMAL NUTRITION AND HEALTH C Mode of action
Ability to induce resistance Relative strength
Potential coverage for Gram-positive bacteria Compatibility with no antibiotic ever program Relative cost
occidia are found anywhere that poultry are raised. The estimated cost of coccidiosis globally is be- tween US$ 9.2 and 15.6 billion, or approximately US$ 0.2 per chicken, derived from performance and
mortality losses and the cost of prophylactics and therapeu- tics. Additional economic impact can also be estimated based on secondary challenges associated with coccidiosis. In poul- try, there are seven Eimeria species of the protozoal parasite coccidia that infect different regions of the intestinal tract. Regardless of the site of infection, Eimeria have a complex life cycle that includes stages within the bird and in the envi- ronment. Depending on the Eimeria species, site of infection and life cycle stage, some prevention strategies may be more effective than others.
Evolution rotation and shuttle programmes Synthetic chemicals, ionophores and the combination of the two have been available for coccidiosis control for more
than 50 years, however, no new anticoccidial drugs have been developed for some time. This makes optimising currently available coccidiosis strategies even more critical. Not all synthetic chemicals have known modes of action but, in general, chemicals disrupt Eimeria by altering their metabolism during their intracellular life cycle stages, and ionophores disrupt Eimeria by altering osmotic balance during their extracellular life cycle stages. These two anticoc- cidial drugs have often been used in combination because of their complementary modes of action and the additional coverage ionophores give for Gram-positive bacteria. This is advantageous because coccidiosis make birds susceptible to clostridial enteritis resulting in high mortality rates and production losses. Thus, using chemicals with ionophores or ionophores alone can provide coverage for both coccid- iosis and clostridial enteritis. Although the combination of chemicals and ionophores has been used successfully for several decades to combat coccidiosis, the development of resistance has been reported. Chemical anticoccidials tend to induce resistance more rapidly compared with ionophores because of their mode of action during the intracellular life cycle of Eimeria. However, this resistance may be masked when using chemical and ionophore blends as Eimeria that are resistant to chemicals may still be responsive to the ionophore making the overall prophylactic use effective. However, the challenge with iono- phores is that they have a very narrow safety range, can con- tribute to reduced performance and may impact heat toler- ance. Many producers have implemented programmes that rotate anticoccidials between flocks (rotation programmes)
Table 1 – Reflections on anticoccidial strategies used in commercial production.* Chemicals
Ionophores
Eimeria inhibition +++ +++ +
Yes ++
Eimeria inhibition ++ ++ ++ No +
*Sources available on request. **Feed additives may include phytogenics, prebiotics, probiotics, novel metabolic modulators, etc.
16 ▶ POULTRY WORLD | No. 6, 2022 Vaccines
Host immunity ?
+ +
Yes +
++ +
Yes +
Feed additives**
Varies based on compound used ?
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