Choice of Ionophore Must Consider Different Impacts on Bird FCR and Body Weight, Argues Elanco – INDUSTRY PERSPECTIVES

Coccidiosis is one of the most important issues facing broiler producers, and ionophores are critical tools helping to keep this threat under control. However, the choice of which anticoccidial program is the most appropriate for a given operation depends on several factors, including the need to avoid the development of resistance, its efficacy on the coccidia and its effects on the bird.

That last point is not to be neglected, insists animal health experts at Elanco, because the differences in the anorexic effects caused by different ionophores can have a meaningful impact on body weight and other performance metrics, ultimately affecting the farm’s bottom line. In today’s Industry Perspectives piece, we hear from Tom Jeffers, Adjunct Professor of Animal Science at Cornell University, who explains the established science on ionophores’ effects, followed by Elanco’s George Gould, Poultry Global Marketing, and Monika Rogala-Hnatowska, Poultry Technical Consultant, who present Elanco’s recent findings on the differences between two key ionophores.

[Feedinfo] How important was the discovery of ionophore anticoccidials in tackling the challenge caused by coccidiosis?

[Feedinfo] There are several commercially available ionophores. How are molecules such as salinomycin and narasin different, and why is this important?

[Tom Jeffers] Ionophores differ in their chemical structures, as well as in their potency, thus differing in their effectiveness as anticoccidials for use in broiler rations. However, all ionophores have the same general mode of anticoccidial action, in that they all transport cations such as sodium or potassium across the bilipid membrane enclosing the invasive stage of the coccidia (the sporozoite), leading to a damaging osmotic imbalance within the sporozoite and in turn, resulting in the death of the sporozoite. Not all ionophores are equally effective in this regard.

Aside from differences in anticoccidial effectiveness, many ionophores have deleterious effects on broilers, while others, such as narasin, do not show such effects meaning the broiler maintains feed intake, control of coccidiosis, and thus optimal intestinal integrity.

Furthermore, in considering differences among the ionophores, one must always bear in mind that the anticoccidial product offered to the broiler producer is not the ionophore molecule, but instead a premix containing the ionophore molecules. It is widely recognized that ionophore premixes differ in their overall quality, affecting their mixability in feed manufacturing and in turn resulting in differences in homogeneity and stability of the respective ionophore in the final ration.

[Feedinfo] A lot of the studies that identify the efficacy of and differences between ionophores are very old. Do their findings still hold up today, and what can these studies tell us?

[Tom Jeffers] While many of the scientific studies of the anticoccidial properties of the ionophores were conducted years ago, the ionophores themselves have not changed in the intervening years. If one assumes that these studies, although conducted some years ago, were properly designed and the results of these studies were published in reputable scientific journals, it is safe to say that the conclusions of such studies remain as valid today as when the studies were conducted.

Of course, broiler growth rate and feed efficiency would differ from these same parameters today as a result of the incredible genetic improvement in broiler performance over the years.

[Feedinfo] Why does Elanco see narasin as the ionophore of choice in broiler production?

The second factor, however, is where we see perhaps a greater difference, and relates to the impact of the ionophore on the bird. As mentioned, many ionophores when present in the ration have a negative impact on the bird, often manifesting as a decrease in feed intake or period of anorexia. This has been established by many published studies examining the effects of salinomycin, monensin and lasalocid on broilers (Metzler et al. 1987, Weppelman et al. 1977, or Harms and Buresh 1987). Interestingly the literature on this subject does not identify the same anorexic effect with narasin and indicates that this ionophore in particular has little to no negative effect on broiler performance.

As such, considering narasin is performing at least as well as others in terms of coccidiosis control, it therefore becomes a superior option to other ionophores, since we do not see this impact on feed intake and the associated performance consequences (lost average daily gain [ADG], lower body weights [BW]).

[Feedinfo] Elanco has been working to update our understanding of the differences in performance between salinomycin and narasin. Can you briefly describe the different pen and field studies you have carried out in the last three years on this issue and the key findings?
[George Gould] While we know that the molecules in question have not changed over time, it is fair to say that both broiler genetics and husbandry have, as mentioned by Professor Jeffers. While we recognized the value of the literature on ionophores, we felt it important to try to evaluate how the differences between ionophores play out in a modern broiler under modern conditions. In particular, we wanted to evaluate how salinomycin and narasin compare with regards to both coccidiosis control and zootechnical parameters under European production conditions. We therefore designed a large scale pen study in Europe using a coccidiosis challenge from both an Eimeria inoculum and reused litter. The study treatment groups included one with a full program (0-42 days) of narasin at 70mg/kg compared with a full treatment of salinomycin at 60mg/kg. This would enable us to identify whether the anorexic effects of salinomycin identified decades ago still had an impact in modern broilers.

The results of the study demonstrated that, under this relatively low cocci challenge, both treatments offered adequate control of lesions. Interestingly, however, the zootechnical data showed narasin, compared to salinomycin, significantly increased average daily feed intake (ADFI) by +2.9% during the whole growout of 42d. Consequently, ADG and final BW were also improved with a final BW difference of 64 grams.

The study was followed up by a customer field evaluation in the EU where a customer ran a full narasin program (0-42 days) in parallel with a salinomycin program (0-42 days) under full commercial conditions. The customer data not only reflected the findings on ADG and BW with significant differences of 2.7g ADG and 113g BW, but also showed a significant improvement in feed efficiency in the narasin group.

[Feedinfo] Is there still a pronounced difference when the products are used as part of a shuttle program, or under different production systems?

[Monika Rogala-Hnatowska] Clearly if there are differences between products, you will see a greater difference the longer they are used “head to head” as it were. However, the study in Poland does demonstrate that whether used as a full program or as part of a shuttle, broiler producers will see significant improvements in feed intake and weight gain when using narasin.

Of further interest was a peer reviewed study in China which compares, among others, narasin and salinomycin as part of a shuttle with a cocci vaccine, but this time in local broiler breeds grown for 75 days. Interestingly in spite of the difference in production system and breeds, the same significant differences in ADFI and ADG were seen as in our European studies.

It indicates to us that, while the initial studies on ionophores may be decades old, the same lessons we learnt then are true now. It also reaffirms for us that narasin likely offers a much greater return for broiler producers worldwide.

[Feedinfo] In light of the findings from these studies, are you able to project what this amounts to in terms of the farmer’s bottom line?

[Monika Rogala-Hnatowska] Often enough there is a lot of focus given to the input costs of production (e.g. anticoccidial program), which is totally understandable these days. However, if we also consider the outputs of production, like final BW or FCR, it becomes clear that an anticoccidial program perceived to be more expensive can deliver better end results. You often only need 1 or 2 points of FCR improvement to easily cover the higher input costs. The same principle applies also when looking at final body weight differences.

The results of our most recent experiments have shown a consistent benefit of narasin-based programs: 3 to 5 points better FCR and bodyweights improved by 100 g or more. At the present, with the monetary value of 1 point of feed-conversion being around EUR 1.2 cents, this means that even in difficult economic times like the previous 18 to 24 months, a very good economic benefit can be achieved.

Published in association with Elanco