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.

RESUMO Foram conduzidos dois experimentos com o objetivo de determinar o valor nutricional e avaliar o desempenho e características da carcaça de suínos alimentados com farelo de canola (Brassica napus). No Experimento I, foi conduzido um ensaio de digestibilidade total com 14 suínos mestiços de linhagem comercial, machos castrados, com 60,69 ± 4,26 kg de PV inicial. O alimento teste farelo de canola (FC), substituiu em 25% a ração referência à base de milho e farelo de soja. Cada suíno constituiu uma unidade experimental, totalizando sete unidades experimentais por ração. Os valores de energia digestível (ED) e energia metabolizável (EM) na matéria natural para o FC foram de 2995 kcal/kg e 2796 kcal/kg, respectivamente. No Experimento II, foram utilizados 50 suínos mestiços, com peso vivo inicial de 29,90 ± 1,16 kg e final de 60,33 ± 3,38 kg, na fase de crescimento, e peso vivo inicial de 60,37 ± 1,6 kg e final de 90,37 ± 3,19 kg na fase de terminação. Foi utilizado o delineamento de blocos inteiramente casualizados, com quatro tratamentos, (6, 12, 18 e 24% de FC), com 10 repetições e um suíno por unidade experimental. Adicionalmente, foi formulada uma ração testemunha, contendo 0% de FC. Os dados foram submetidos à análise de variância e adicionalmente foi aplicado o Teste de Dunnett, e análise de regressão, a 5% de probabilidade. Os resultados sugerem que é possível incluir até 24% de FC nas dietas de suínos, em crescimento e terminação, sem prejudicar o desempenho e as características da carcaça.

ABSTRACT Two experiments were performed for the purpose of determining the nutritional value and assess the performance and carcass traits in pigs fed on canola meal (Brassica napus). Experiment I consisted of a total digestibility trial conducted with 14 castrated commercial crossbred male pigs with 60.69 ± 4.26 kg initial live weight. The treatments consisted of a control diet based on maize and soybean meal and another diet containing canola meal (control + 25% canola meal). Each pig was an experimental unit, totalling seven experimental units per diet. The digestible energy and the metabolizable energy of canola meal used was 2,999 and 2,730 kcal.kg-1, respectively. These values were used to formulate the diets of the performance experiment. Experiment II included 50 crossbred pigs with an average initial live weight of 29.90 ± 1.16 kg and an average final live weight of 60.33 ± 3.38 kg during the growing phase, and an average initial live weight of 60.37 ± 1.6 kg and an average final live weight of 90.37 ± 3.19 kg during the finishing phase. The experimental design consisted of randomized blocks, with four treatments (6, 12, 18, and 24% canola meal), 10 repetitions, and one pig per experimental unit. The control diet was formulated with 0% canola meal. The data were assessed using ANOVA test and the averages of the treatments were compared using Dunnett's test and regression analysis at a 5% probability level. The results suggest that it is possible to use up to 24% canola meal in the diets for pigs during the growing and finishing phases without affecting the performance and carcass traits.