Purpose Use a holistic individual life cycle assessment (LCA) to investigate possible mitigation of environmental impacts through optimisation of overall farm feed efficiency by combining animal selection for feed efficiency and formulation of diets with minimum environmental impacts tailored to pig nutritional requirements. Methods A linear multi-objective optimisation method was used to combine diet optimisation tailored to meet the representative nutritional requirements of genetic lines with environmental optimisation of the environmental impacts of the diet. Environmental optimisation was obtained by weighting the environmental impacts of the diet in a single environmental impact score. An individual trait-based LCA model with a cradle-to-farm-gate system boundary and functional unit of 1 kg live pig at the farm gate was applied to genetic lines selected for high (LRFI, high feed efficient line) and low (HRFI, low feed efficient line) feed efficiency data. The production traits of each individual animal in response to the optimised diets were simulated with InraPorc® and imported into the individual LCA model to assess global warming potential (GWP), terrestrial acidification potential (AP), freshwater eutrophication potential (EP), and land occupation (LO) of the overall farm feed efficiency approach. Results and discussion Integrating selection for feed efficiency, nutritional requirements of genetic lines (HRFI and LRFI) and environmental diet optimisation resulted in overall mitigation of environmental impacts. Compared to the conventional diet, the environmental score of the optimised tailored diets was reduced by 5.8% and 5.2% for LRFI and HRFI lines, respectively. At the general production system level, the environmental impacts decreased by an average of 4.2% for LRFI and 3.8% for HRFI lines compared to environmental impacts of the lines fed the conventional diet ( P < 0.05). The HRFI line with its optimised tailored diet had fewer impacts than the LRFI line with the conventional diet, except for EP. Individual LCA revealed high correlations between environmental impacts and feed efficiency and protein deposition traits. Conclusions Implementation of overall farm feed efficiency would effectively mitigate environmental impacts. A holistic economic evaluation of the resulting trade-off between diet costs and pig performances is now needed to design a comprehensive tool to orientate selection and formulation decisions for sustainable pig production systems.

中文翻译：

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在养猪生产中实现整体农场饲料效率的方法：通过个体生命周期评估进行环境评估

目的 使用整体个体生命周期评估 (LCA)，通过将动物选择以提高饲料效率和日粮配方与针对猪营养需求量身定制的最小环境影响相结合，通过优化整体农场饲料效率来研究减轻环境影响的可能性。方法 采用线性多目标优化方法，将满足遗传品系代表性营养需求的日粮优化与日粮环境影响的环境优化相结合。通过在单个环境影响评分中加权饮食的环境影响来获得环境优化。基于个体性状的 LCA 模型具有从摇篮到农场门系统边界和农场门口 1 kg 生猪的功能单元，应用于选择高（LRFI，高饲料效率线）和低（HRFI）的遗传系，低进料效率线）进料效率数据。用 InraPorc® 模拟每只动物对优化饮食的生产性状，并将其导入个体 LCA 模型以评估全球变暖潜能 (GWP)、陆地酸化潜能 (AP)、淡水富营养化潜能 (EP) 和土地总体农场饲料效率方法的占用 (LO)。结果和讨论 综合选择饲料效率、遗传品系的营养需求（HRFI 和 LRFI）和环境日粮优化，总体上减轻了环境影响。与传统日粮相比，LRFI 和 HRFI 品系的优化定制日粮的环境评分分别降低了 5.8% 和 5.2%。在一般生产系统水平上，与饲喂传统日粮的品系的环境影响相比，LRFI 品系的环境影响平均降低 4.2%，HRFI 品系的环境影响平均降低 3.8%（ P < 0.05）。除 EP 外，具有优化定制饮食的 HRFI 系比具有常规饮食的 LRFI 系的影响更小。个别 LCA 揭示了环境影响与饲料效率和蛋白质沉积特性之间的高度相关性。结论 实施整体农场饲料效率将有效减轻环境影响。