ARTICLE 60 FEED & ADDITIVE MAGAZINE August 2022 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 while using chemical and ionophore blends as Eimeria that are resistant to chemical may still have susceptibility to the ionophore making the overall prophylactic use effective. However, the challenge with ionophores is that they have a very narrow range for safety, can contribute to reduced performance and may impact heat tolerance. Many producers have implemented programs that rotate anticoccidials between flocks (rotation programs) or use different anticoccidials in starter, grower and finisher rations (shuttle programs) to maintain or improve Eimeria drug sensitivity. Another strategy to improve drug sensitivity has been to switch from anticoccidial drugs to using a coccidia vaccine. Coccidia vaccines are based on specific Eimeria species and induce immunity three to four weeks after vaccination (Tewari and Maharana, 2011). Introducing non-resistant Eimeria via vaccination can repopulate the environment to restore drug sensitivity. However, the effectiveness of this strategy to restore environmental Eimeria drug sensitivity may be impacted by litter management strategies (i.e., raising birds on fresh litter for each cycle or using re-used litter for several cycles). One challenge with coccidia vaccines is that they tend to impact performance during the time the birds are acquiring immunity. This associated performance loss is more challenging to overcome when birds are marketed at a younger age compared to those marketed at an older age because there is limited time to regain that lost performance. Recovering performance loss associated with vaccination is one area in which feed additives can be used as part of a coccidiosis management strategy. Feed additives such as probiotics, prebiotics and phytogenics have become part of many coccidiosis management strategies because of their compliance with programs like no antibiotics ever or antibiotic-free and for their unique modes of action that compliment different rotation and shuttle programs. For example, Eimeria disrupt the intestine and nutrients are leaked into the lumen; live probiotics can help overcome this by improving intestinal integrity whereas microbial metabolic modulators can redirect those leaked nutrients towards beneficial microbial metabolism. If resistance is becoming a concern or you are seeking an alternative, using phytogenic-saponin blends may be a way to give a Figure 1. Rotation, shuttle, and bio-shuttle program examples used in commercial production* *Figure highlights an example of programs, descriptors used may vary by country and product category regulation.
RkJQdWJsaXNoZXIy MTUxNjkxNQ==