intestinal function and the immune system. “Our nutrition- ists, who have started to look at diet formulations in a new way, are taking a total nutrition approach,” she reports. “Nu- trient levels in diets haven’t changed much over the years – the main difference is how these nutrients are provided. This has led to an increased focus on ingredient sourcing, as there is value in understanding the differences in digestibility, which will lead to more effective diet formulations.” Crowder also explains that additives can be highly effective at low inclusions levels. “Nursery formulations have been used where the majority of in-feed antibiotics are included in swine nutrition,” she says. “Those formulas are very com- plex and space in the diet is at a premium. That’s why inclu- sion and mode of action are extremely important.”

Other critical aspects At Alltech, a primary focus in RWA feed development is achieving an ideal stomach pH in pigs after weaning. This starts digestive enzyme secretion as soon as possible, leav- ing less undigested nutrient for pathogens, explains Aimé Roy, Alltech technical swine liaison in Canada. Another criti- cal aspect for Roy in RWA feed manufacture is mycotoxins. “Most of the time, we underestimate the negative effects of mycotoxins that are detrimental to the immune system,” he says. In addition, “the control of oxidative stress is increasing- ly recognised as an essential strategy for reaching full genet- ic potential.” Alltech US swine business leader Russell Gilliam notes that for successful RWA feed development and use, the firm’s ‘production teams’ play a big role, as they help the firm’s nu- trition and veterinary team keep abreast of any challenges that develop, and this makes quick changes in the plan of ac- tion possible. “There are several [pork production] compa- nies that have been very successful at doing this and I be- lieve that a lot of their success stems from making sure that everyone on the team is engaged and all opinions and ideas are seen as having value as the plan is put into place.”

Meeting the challenges In terms of what’s been most challenging in making feed that optimises the performance of pigs in RWA production, Schumann lists respiratory disease as a long-term issue that still lingers. “Although we can boost the pigs’ immune re- sponse with antioxidants such as Vitamin E and selenium, and take care of the gut with many nutritional technologies,” he explains, “respiratory disease is still a serious threat. Better environmental controls and better husbandry are very important.” The second-largest challenge in Schumann’s view is develop- ing feeds for piglets that suffer from typical post-wean scour: “Especially given that the industry will be significantly re- stricted in the amount of zinc that can be used.” Another challenge noted by Roy is to reduce the amount of

Feed is obviously also a critical aspect of successful raised-without-antibiotics (RWA) production.

undigested nutrients in the digestive tract of nursery pigs – nutrients that are thus available for pathogens like E. coli to feed on. She says a viable strategy for this could involve re- ducing crude protein content through the incorporation of synthetic amino acids such as valine.

Looking ahead Like all feed companies, Grand Valley constantly examines new ingredients. In Canada, there will be more of those to analyse in the near future. Schumann explains that the Cana- dian Food Inspection Agency (CFIA) is in the process of eas- ing some regulatory restrictions on feed ingredients and that some products that have been available internationally for quite a while will be receiving registration in Canada – in particular, probiotics blends and acid blends. Schumann be- lieves that RWA production should get easier as the number of vaccines continues to grow. Also important, in his view, will be the use of dried fermenta- tion products that reduce the severity of a disease challenge mounted by a pathogen population. These products prevent ‘quorum sensing,’ where pathogens sense their own num- bers and at a certain density, are triggered to start a disease process in the host. For her part, Crowder believes there will be an increased focus on “nutritional immunology” in animal production, meaning an increased “understanding of how we can better support the immune system of an animal through nutrition.” She also believes “we’ll see an increase of non-nutritional ad- ditives focused on health, environment and biosecurity on the farm, as well as food safety. These haven’t so far been a focus on the nutritional side of feed formulation, but will be an area in which nutritionists will play a key role in the future.”

▶PIG PROGRESS | Volume 36, No. 4, 2020 43


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