Regulatory recognition of the prophylactic effects of feed additives including organic acids, butyrates, botanicals, yeasts, or pro and prebiotics on animal health should further facilitate progress in the reduction of global antimicrobial resistance (AMR), noted Leo den Hartog, director of R&D at Trouw Nutrition.
He drew such a conclusion in a recently published Feedipedia paper outlining effective nutritional strategies to reduce antibiotic use in livestock production, co-authored by his Nutreco colleague, Coen Smits, and Wouter Hendriks of Wagenignen University.
Also part-time professor in sustainable animal nutrition in production chains at Wageningen University, den Hartog told FeedNavigator this week:
“The feed additives and dietary measures described in the paper contribute in general to mitigation of health risks of animals.
“We [wrote] about the functional effects of already approved ingredients. Many of these measures do not consistently improve productivity in non-challenged conditions and, therefore, cannot be treated as ‘zootechnical’ or performance enhancing additives.
“There is no regulatory space at this moment to claim mitigation of health risks, in general, and we would like to invite regulatory bodies to think and create proactively a regulatory space where it will be possible to claim such risk mitigating effects.”
Experiments
In a series of studies, den Hartog et al said they tested a specific combination of organic acids, with butyrate, medium chain fatty acids (MCFA) and a selected phenolic compound in both broiler chickens and piglets.
The butyrate and MCFA component had controlled-release properties to deliver the bioactive in more distal sections of the gastrointestinal tract, they reported.
On average, the team said they saw a significant improvement in average daily gain and feed efficiency of respectively 3 and 1%.
The diarrhea incidence tended to be lower in piglets fed the additive blend, added the Dutch team.
Those effects were in line with the magnitude of the responses described by Laxminarayan et al. (2015) for antibiotic growth promoters (AGP), noted the authors.
“In challenge conditions, the effect of the feed additive blend on average daily gain and feed efficiency was more pronounced, demonstrating indirectly that this intervention strategy may, at least partially, prevent or ameliorate the possible effect of infectious challenges.
“Such combination concepts should not be seen as ‘curative’ but may contribute to the prophylaxis of specific enteric diseases and disorders. In the above mentioned blend, probiotics or prebiotics were not applied, but, also, these additives may be used as effective tools for creating synergistic blends to support gastrointestinal health.
“However, we observed less consistent results in experiments with specific added probiotics and prebiotics in earlier research (unpublished data),” wrote den Hartog et al.
They argued that feed additives can create a strong mucosal barrier in pigs and poultry by enforcing gut integrity and modulating the immune system in such a way that the response is adequate but not excessive so as to avoid inflammation.
The researchers said the global feed industry can play a major role in lowering AMR by adopting new insights and novel technologies in feed formulations and feed additives. The speed at which this adoption can be implemented will be critical though, stressed den Hartog et al.
Source: Feedipedia, Broadening Horizons N°34, October 2016
Title: Feed additive strategies for replacement of antimicrobial growth promoters and a responsible use of antibiotics
Authors: LA den Hartog, CHM Smits, WH Hendriks