Effect of observed individual data of performance and excretion on life cycle assessment of piglets

ABSTRACT: The objective was to evaluate the impact of producing piglets fed diets with different crude protein (CP) levels through life cycle assessment and experimental data. In Trial I (performance), 28 crossbred barrow piglets, with an initial average weight of 15.3 ± 1.15 kg were divided into a randomized block design with four treatments, seven replications and one animal per experimental unit. In Trial II (nitrogen and phosphorus balance), 20 crossbred barrow piglets with an average weight of 21.4 ± 1.62 kg were divided in a randomized block design with four treatments, five replications and one animal per experimental unit. Four experimental feeds were evaluated: HighCP, CP18, CP17 and LowCP, with 19, 18, 17 and 16 % of CP, meeting the requirements of digestible amino acids through industrial amino acid (IAA) addition. From Trial I and II data, the environmental impact was calculated for global warming potential, acidification potential, eutrophication potential, cumulative energy demand, terrestrial ecotoxicity and land occupation (LO). Total nitrogen excretion decreased by 0.226 g d−1 for each 1 g of reduction on daily nitrogen intake. However, there was no statistical difference (p > 0.05) among experimental treatments for all impact categories. For LO, there was a reduction (p = 0.078) of impact with CP reduction, which was 8 % lower with the LowCP diet, in comparison with HighCP. Dietary CP reduction for piglets from 15 to 30 kg, through IAA supplementation, reduced the environmental impact under LO, considering soybean meal from southern Brazil and observed individual data of performance and excretion.

摘要：本研究旨在通过生命周期评估与试验数据，评估饲喂不同粗蛋白质（crude protein, CP）水平日粮的仔猪生产过程的环境影响。试验一（生长性能试验）：选取28头初始平均体重为15.3±1.15 kg的杂交去势公仔猪，采用随机区组设计，设置4个处理组、7个重复，每个试验单元包含1头试验猪。试验二（氮磷平衡试验）：选取20头平均体重为21.4±1.62 kg的杂交去势公仔猪，采用随机区组设计，设置4个处理组、5个重复，每个试验单元包含1头试验猪。本试验共设置4种日粮：HighCP、CP18、CP17及LowCP，其粗蛋白质含量分别为19%、18%、17%及16%，通过添加工业合成氨基酸（industrial amino acid, IAA）满足可消化氨基酸需求。基于试验一与试验二的数据，本研究计算了以下环境影响指标：全球变暖潜势、酸化潜势、富营养化潜势、累积能量需求、陆地生态毒性及土地占用（land occupation, LO）。每日氮摄入量每减少1 g，总氮排泄量即降低0.226 g·d⁻¹。但各试验处理组在所有环境影响类别中均无统计学差异（p>0.05）。就土地占用指标而言，随着粗蛋白质水平降低，环境影响呈下降趋势（p=0.078），其中LowCP日粮组的环境影响较HighCP日粮组低8%。综合巴西南部大豆原料来源以及观测到的生长性能与排泄数据，对于15~30 kg体重阶段的仔猪，通过添加工业合成氨基酸降低日粮粗蛋白质水平，可降低土地占用维度的环境影响。