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Intensification and concentration of pig farming in certain regions, such as Brittany, has created environmental issues. Nutrients excreted (N, P, Cu, K, ...) by animals into the environment impact the quality of the soil, the water and the air. Because of the low absorption capacity of copper (Cu) and zinc (Zn) by pigs, this trace elements are strongly excreted and enhance this environmental risk.

Cu and Zn are essential to improve the metabolism of pigs. In fact, they have a key role on gene expression, iron transport or protecting the organism against oxidative stress (Suttle, 2010). These minerals are added as supplements in pig feed to meet their requirements (5-6 ppm for Cu and 50 ppm for Zn) (NRC, 2012). Moreover, this supplementation offset antagonism effect of certain elements (such as phytates and calcium), which are responsible for the decrease of availability and absorption of Cu and Zn (Jondreville et. al, 2002 ; Revy et al., 2003).
Then, a large amount (80-90%) of ingested Cu and Zn ends in pig effluents. Raw slurry can contain up to 1000 ppm of Cu and 2000 ppm of Zn (Dourmad et al., 2002; Jondreville et al., 2002). The most common practice for managing this waste is the direct land application of effluent. Consequently, the increases of Cu and Zn in the soil can lead to reduced yields per hectare for certain crops (Hartman 1978; Mc Grath, 1980) or to negatively impact soil composition and its microbial activity (Mc Grath et al, 1995). There are different strategies to reduce this accumulation. Reduction of Cu and Zn in feed can decrease their amount excreted. Regulations have already been evolved in recent years to better control this excess (EU 2016/1095, EU 2018/1039). However, it’s possible to better reduce Cu and Zn concentrations in feed. Other strategies are the different manure management approaches (biogas production, compositing…), which have a high interest in adding value to the breeding system. However, few studies have investigated the fate of Cu and Zn in pig manure after these treatments.

Main objectives of the PhD

The main objective of this PhD project is to characterize Cu and Zn flows through the production system (feed -> faeces -> treatment -> soil) according to different manure management approaches and to identify actions triggers to reduce environmental impact of Cu and Zn.
First step is the qualitative & quantitative characterization of Zn and Cu fractions from field samples (feed, feces, manure & digestate coming from Cooperl manure management systems) and creation of a database.
This database will be the support to develop a mathematical prediction model of Zn & Cu flows from feed composition to mineral exportation back to nature (soil).
The last step is the validation of this mathematical prediction model by feeding trials. Zootechnical tests, to evaluate animal performance, and digestibility tests, to quantify Cu and Zn contents of the effluents, will be carried out. UR Opaale will manage the analysis of the products resulting from the effluent treatments.

These different steps will allow us to supervise these elements flows based on animal feeding and to ensure optimal recovery of livestock effluents to add value to the manure while limiting losses to the environment.

Emma Gourlez works on this PhD project since October 2020 for a period of 3 years. It is being conducted within a CIFRE (in French Convention Industrielle de Formation par la Recherche) thesis. The project is financed by Animine, in partnership with INRAE (UMR Pegase and UR Opaale) and Cooperl. Emma is supervised by Francine De Quelen and Jean-Yves Dourmad in the Sysporc team, Fabrice Béline from UR Opaale and Alessandra Monteiro from Animine.

References

• Commission Implementing Regulation (EU) 2016/1095 du 6 juillet 2016.
• Commission Implementing Regulation (EU) 2018/1039 du 23 juillet 2018.
• Jean-Yves Dourmad, Candido Pomar, D. Masse. Modélisation du flux de composés à risque pour l'environnement dans un élevage porcin. 34. pp.183-194. Journées de la Recherche Porcine, Feb 2002, Paris, France. ⟨hal-02826461⟩
• Hartmans J., 1978. Identifying the priority contaminants toxicological aspects of animal effluents. In : Animal and Human Health Hazards associated with the utilization of animal efflents, Kelly W.R. (Ed). EEC Publication, Dublin, Ireland, 35-56.
• Catherine Jondreville, P.S. Revy, Anne Jaffrézic, Jean-Yves Dourmad. Le cuivre dans l'alimentation du porc : oligoélément essentiel, facteur de croissance et risque potentiel pour l'homme et l'environnement. Productions animales, Institut National de la Recherche Agronomique, 2002, 15 (4), pp.247-265. (DOI)
• McGrath M.C, 1980. Implications of applying copper rich pig slurry to grassland; effects on plant and soil. In : Copper in animal wastes ans sewage sludge, : L'Hermite P., Dehandtschutter J. (Ed). Proc. EEC Workshop, INRA Publisher, Bordeaux, France, 144-153. (DOI)
• McGrath S.P., Chaudri A.M., Giller K.E., 1995. Long term effects of metals in sewage sludge on soils, microorganisms and plants. Journal of Industrial  Microbiology, 14, 94-104. (DOI)
• National Research Council (NRC), 2012. Nutrient Requirement of Swine. The National Academies Press, Washington D.C., USA.
• P.S. Revy, Catherine Jondreville, Jean-Yves Dourmad, Yves Nys. Le zinc dans l'alimentation du porc : oligo-élément essentiel et risque potentiel pour l'environnement. Productions animales, Institut National de la Recherche Agronomique, 2003, 16 (1), pp.3-18. (DOI)
• Suttle N.F., 2010. Mineral nutrition of livestock, 4th Edition. Cabi, Oxfordshire, United Kingdom, 579p.

Contact

Emma Gourlez : emma.gourlez[at]inrae.fr (PhD student)
Fabrice Béline : fabrice.beline[at]inrae.fr (thesis director)
Francine De Quelen : francine.dequelen[at]inrae.fr (thesis co-director)
Jean-Yves Dourmad : jean-yves.dourmad[at]inrae.fr (thesis co-director)
Alessandra Monteiro : amonteiro[at]animine.eu (supervisor in Animine)