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Lipase from Aspergillus sp. obtained by solid-state fermentation (SSF) on wheat bran (LWB), soybean bran (LSB) and soybean bran combined with sugarcane bagasse (LSBBC) were 67.5, 58 and 57.3 U of crude lipase per gram substrate, respectively. The optimum pH of activity and stability of the LWB was between 8 and 9, and the optimum temperature of activity and stability was 50°C and up to 60°C, respectively. The LSB and LSBBC showed two peaks of optimum pH (4 and 6) and optimal values of temperature and stability at 50°C. The LSB was stable in the pH range of 6-7, while LSBBC in the range of pH 4-7. All the enzymes show activities on p-nitrophenyl esters (butyrate, laurate and palmitate). LWB stood out either on the hydrolysis of sunflower oil, presenting 66.1% of the activity over commercial lipase and on the esterification of oleic acid and ethanol, surpassing the activities of the commercial lipases studied. The thin layer chromatography showed that LWB and LSB have produced ethyl esters from corn oil, while LWB produced it from sunflower oil.

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Two experiments were conducted to evaluate the effect of replacing lactose with maltodextrin and adding fructooligosaccharides (FOSs) to the feed of weaned piglets. The first experiment was conducted using a randomized block design with a 2 × 2 factorial arrangement (2 sources of carbohydrates: maltodextrin and lactose in the pre-starter feed and with or without the use of 0.3% FOS in the prestarter and starter feeds) with 7 repetitions in 3 animals. Performance and hematological parameters were evaluated. The second experiment was conducted using a randomized block design with a 2 × 2 × 2 + 1 factorial arrangement (2 sources of carbohydrates: maltodextrin and lactose and with or without the use of 0.3% FOS; 2 slaughter dates: 7 and 14 d post-weaning; and slaughter on the day of weaning) with 8 repetitions in 1 animal. The following parameters were evaluated: pH and relative weight of digestive organs, enzyme activity, and microbial population. In the initial phase, maltodextrin did not compromise performance and could replace lactose with economic benefits; however, it does reduce intake of the pre-starter I feed. Maltodextrin has a prebiotic effect because it reduces the total coliform and E. coli populations in the cecum and reduces the pH of the rectal contents. The use of FOSs is not justified, regardless of whether lactose or maltodextrin is added to the feed. Key words: Fructooligosaccharides, lactose, enzymes, microbiota, swine ResumoDois experimentos foram conduzidos com o objetivo de avaliar o efeito da substituição da lactose pela maltodextrina e da adição de frutoligossacarídeos (FOS) nas rações de leitões desmamados. O primeiro experimento apresentou delineamento de blocos casualizados com arranjo fatorial 2 x 2 (duas fontes de carboidratos: maltodextrina e lactose na ração pré-inicial; com ou sem uso de 0,3% de frutoligossacarídeo, nas rações pré-inicial e inicial) com sete repetições de três animais. Foram avaliados o desempenho e parâmetros hematológicos. No segundo experimento foi empregado o delineamento de blocos casualizados em arranjo fatorial 2 x 2 x 2 + 1 (duas fontes de carboidratos: maltodextrina e lactose; com ou sem uso de 0,3% de frutoligossacarídeo; duas épocas de abate: sete e quatorze dias pós-desmame; e abate no dia do desmame) com oito repetições de um animal. Foram avaliados o pH e peso relativo de órgãos do sistema digestório, atividade enzimática e população microbiana. Na fase inicial a maltodextrina não compromete o desempenho e pode substituir com vantagem econômica a lactose, contudo, reduz a ingestão da ração pré-inicial I. A maltodextrina possui efeito prebiótico, pois reduz a população de coliformes totais e de E. coli no ceco e o pH do conteúdo do reto. O uso de frutoligossacarídeo não se justifica independente de se usar lactose ou maltodextrina nas rações.