# Approaches for reducing nitrogenous/phosphorus waste excretion in the pig - challenges and opportunities

Léa Cappelaere, Florence Garcia-Launay, Patrick Schlegel, Marie-Pierre Létourneau Montminy

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Léa Cappelaere, Florence Garcia-Launay, Patrick Schlegel, Marie-Pierre Létourneau Montminy. Approaches for reducing nitrogenous/phosphorus waste excretion in the pig - challenges and opportunities. 16. International Symposium on Digestive Physiology of Pigs (DPP2025), DPP-North America, May 2025, Lake Geneva, Wisconsin, United States. n.p. hal-05425863

HAL Id: hal-05425863

https://hal.inrae.fr/hal-05425863v1

Submitted on 19 Dec 2025

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FROM DISCOVERY TO
DEVELOPMENT

Digestive Physiology of Pigs - North America:
16th International Symposium on Digestive Physiology of Pigs

May 20-23, 2025 | Grand Geneva Resort & Spa | Lake Geneva, WI USA

Theme III: Functional Ingredients and Utilization of Feed Resources for Improved Digestive Function and
Nutrient Efficiency

**118 Approaches for reducing nitrogenous/phosphorus waste excretion in the pig - challenges and opportunities.** Léa Cappelaere¹,², Florence Garcia-Launay³, Patrick Schlegel², and Marie-Pierre Létourneau Montminy*¹,

¹Laval University, Quebec, Quebec, Canada, ²Agroscope, Posieux, Switzerland, ³INRAE UMR PEGASE, Saint-Gilles, Britanny, France. The intensification of agricultural systems has increased yields and efficiencies, reducing environmental impacts and production costs. However, nutrient cycles have become dissociated in many agricultural systems, including swine production systems. Losses of nitrogen (N) and phosphorus (P) from manure lead to severe eutrophication and acidification problems in many regions of the world, as well as greenhouse gases emissions; but they are also essential nutrients for crop production. In a dissociated nutrient cycle, the use of mineral phosphate and urea as fertilizers becomes essential. For animal, P is essential for growth performance and bone mineralization. Additionally, since it is a limited and non-renewable resource produce by few countries, phosphate, dictates our capacity to produce food. Therefore, an efficient use of plant P by pigs and a consequent use of excreted P as fertilizer for crop production is necessary. N is also essential for animal and plant production. N is not a finite resource, but production of mineral N fertilizers requires a high energy input and protein-rich feedstuffs can have a high negative environmental impact depending on production context which requires to reduce N excesses. These environmental challenges are even-more relevant for competitiveness given the higher prices of raw materials and N and P inputs for feedstuffs in recent years. In consequence, there is an urgent need to optimize utilisation of resources such as P and N. To achieve this, an accurate and robust feeding system for P (including calcium (Ca) given their many interactions) and N (including amino acids (AA)) is needed. This involves setting up a system that 1) accurately and robustly determines the P, Ca and AA content of feed ingredients, 2) determines precisely the P, Ca and AA requirements of animals, 3) provides these nutrients to animals as accurately as possible and 4) integrates innovative feeding strategies to optimize their utilization by animals. **Key Words:** Phosphorus, nitrogen, environment

**119 Improving starch digestion in barley, wheat and maize by xylanase/glucanase, phytase, protease and their combination in an in vitro digestion model.** X. Liu*¹, B.M. Flanagan¹, E. Roura¹,², and M.J. Gidley¹, ¹Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland, Australia, ²Centre for Animal Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland, Australia. Grains are the primary source of energy in pig diets. This study investigated the effects of commercial exogenous enzyme feed additives on starch digestion in hammer-milled barley, wheat, and maize grains, using an in vitro digestion model. A 5 × 3 factorial design was used to test five enzyme treatments (control, phytase, xylanase/glucanase, protease, and Combo - a combination of all enzymes) across the three grains. The digestion model was adapted from the standard Infogest 2.0 method, which simulates oral (2 min, pH 7), gastric (2 hr, pH 3), and small intestinal (8 hr, pH 7) digestion. Digesta samples were collected at 0, 20, 40, 60, 120, 180, 240, 360 and 480 mins during small intestinal digestion. Starch digestion was quantified by two parameters: (1) starch digestibility and (2) digestion rate coefficient, which represent how much and how fast starch was digested respectively. The effect of enzyme treatments on starch digestion for each grain was analysed using one-way ANOVA followed by Tukey's post-hoc test. Our results indicate that the enzyme treatments improved starch digestion parameters of the three grains to different extents. In barley, xylanase/glucanase and Combo significantly improved both starch digestibility and digestion rate coefficient (*P* < 0.05) while phytase significantly improved digestion rate coefficient and tended to increase starch digestibility (*p* = 0.051). In wheat, all the enzymes tested significantly improved starch digestibility (*P* < 0.05) and xylanase/glucanase also significantly improved digestion rate coefficient (*P* < 0.05). In contrast, for maize, only phytase and Combo significantly improved both starch digestibility and

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