Análise do ciclo de vida na produção de suínos: efeito da redução do conteúdo de proteína bruta da dieta

• Ano de defesa: 2017
• Autor(a) principal: Monteiro, Alessandra Nardina Trícia Rigo
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual de Maringá; Brasil; Programa de Pós-Graduação em Zootecnia; UEM; Maringá, PR; Centro de Ciências Agrárias
• Palavras-chave em Português: Suínos; Produção; Impacto ambiental; Emissão de carbono; Meio ambiente; Alimentação de suínos; Modelos de predição; Produção de suínos; Nitrogênio; Modelagem; Brasil.; Carbon emission; Environment; Modelling; Nitrogen; Brazil.; Ciências Agrárias; Zootecnia
• Link de acesso: http://repositorio.uem.br:8080/jspui/handle/1/1499

The objective of this study was to calculate the environmental impact of pig production, fed different dietary crude protein (CP) levels, through life cycle assessment (LCA), and confront estimated data and observed data, used as inputs and outputs of LCA, through Bayesian approach. In the first study, two trials were conducted. In the Trial I (growth performance from 15 to 30 kg), 28 barrows piglets with 15.3±1.5 kg were distributed in a randomized block design with four treatments, seven replicates and one animal per experimental unit. In the Trial II (nitrogen and phosphorus balance from 15 to 30 kg), 20 barrows piglets with 21.4±1.6 kg were distributed in a randomized block design with four treatments, five replicates and one animal per experimental unit. The treatments consisted of four diets, in which the CP content was increasingly reduced in one percentual point (19.24; 18.24; 17.24 e 16.24%), being the digestible amino acid requirements met by adding L-lysine, DL-methionine, L-threonine, L-tryptophan, L-valine and L-isoleucine. From Trials I and II data, the LCA of piglet production was calculated for global warming potential (GWP), acidification potential (AC), eutrophication potential (EU), cumulative energy demand (CED), terrestrial ecotocicity (TE) and land occupation (LO). The nitrogen and phosphorus excretion were reduced by dietary CP reduction. Total nitrogen excreted was reduced by 0.238 g/d for each 1g of reduction in daily nitrogen intake. However, no effect was observed (P>0.05) for GWP, AC, EP, CED and TE. For LO category, a reduction (P=0.078) was observed in reducing the impact through dietary CP reduction, which was 8% lower in 16.24% CP diet, in relation to 19.24% CP diet. In the second study, the LCA was performed from performance and nutrient excretion data estimated by InraPorc® software. Treatments were the same as first study. Growth performance and nutrient excretion, from 15 to 30 kg, were simulated for each CP level, by using InraPorc®. Estimated and observed data were compared by using paired t-test through Bayesian analysis. The nitrogen and phosphorus excretion were reduced by 15 and 21%, respectively, moving from high CP level diet to low CP diet. In the same way, AC and EU were reduced by 4% and LO by 8%, comparing 19.24% CP diet with 16.24% CP diet. However, the impact under GWP, CED and TE increased with the dietary CP reduction. Bayesian analysis showed similiratity (0∉CIr) between estimated and observed data for feed intake, phosphorus excreted, and the categories CED, TE and LO. In the thirdy study, the LCA methodology was applied to growing-finishing pigs. A virtual population of 1000 gilts and 1000 barrows was created, from growing and feed intake parameters obtained in previous trials. Three feed formulations were evaluated: without industrial amino acids (noAA) diet, with industrial amino acids and minimum crude protein (CP) content (withAA), and with industrial amino acids without CP constraint (lowCP). Performance and excretion of pigs, from 30 to 115 kg, were simulated for each amino acid utilization scenario, using InraPorc® population model, considering between-animal variability. The nitrogen excretion was reduced with industrial amino acids incorporation. However, an increase in GWP was observed, in which the lowest impact was obtained for noAA diets (2.38 kg CO2-eq.). Similar effects were observed for CED and TE, with an increase of 9 and 8%, respectively, moving from noAA to lowCP diet. Conversely, AC and EU were reduced by 11 and 13%, respectively, at the lowCP scenario. In the same way, LO was reduced about 7%, when industrial amino acids incorporation was increased in diets. In conclusion, the dietary CP reduction was efficient to reduce nitrogen excretion, both in experimental and computer simulation data. However, for environmental impact categories modelled through LCA, this reduction brings benefits for LO (observed experimental data). For estimated data, the dietary CP reduction decreased the impact under nitrogen-dependent variables, as AC and EU, being those estimated data similar to observed data for CED, TE and LO.