RESUMO Os frutanos do tipo inulina são oligossacarídeos que favorecem a multiplicação de determinados gêneros bacterianos no intestino, promovendo um efeito prebiótico. Este trabalho avaliou o efeito da inulina extraída de raízes de yacon (Smallanthus sonchifolius) sobre a colonização intestinal de frangos de corte experimentalmente infectados por Salmonella Enteritidis. Sessenta frangos de corte com um dia de idade foram divididos em três grupos de tratamento, com duas repetições, criados até 21 dias. As aves do grupo yacon receberam 100mg de inulina/dia, via oral, por três dias consecutivos. No sétimo dia de vida, as aves tratadas e o controle positivo foram desafiados pela via oral com uma cultura de S. Enteritidis. Não foram observadas diferenças de desempenho zootécnico entre os grupos. O índice de infectividade das aves suplementadas com yacon foi menor até o sexto dia após o desafio, mas, ao término do experimento, foi superior ao controle positivo. Os dados deste trabalho demonstram que o uso da inulina nos três primeiros dias de vida promoveu uma redução da colonização intestinal dos frangos por Salmonella Enteritidis na primeira semana após o desafio. Novos estudos são necessários para determinar a dose e o tempo de tratamento ideal para um efeito protetor de maior duração.

ABSTRACT The fructan inulin-type oligosaccharides favor the multiplication of some bacterial genera in the intestine, promoting a prebiotic effect. This study evaluated the effect of inulin extracted from yacon roots (Smallanthus sonchifolius) on intestinal colonization of broilers experimentally infected with Salmonella Enteritidis. Sixty-one day old chicks were grouped into three treatments, with two replicates, and reared until 21 days. Birds in the yacon group received 100mg of inulin/day orally for three consecutive days. On the seventh day of life the treated birds and the positive control were challenged orally with a culture of S. Enteritidis. There were no differences between groups in live performance. The infectivity index of the chicks supplemented with yacon was lower until the sixth day after the challenge, but at the end of the experiment it was higher than the positive control. Data from this study show that the use of inulin during the first 3 days of life caused a reduction of intestinal colonization of chickens by Salmonella Enteritidis in the first week after challenge. Further studies are needed to determine the dose and the ideal time of treatment necessary for a longer protective effect.

Sucrose:sucrose fructosyltransferase (SST) and fructan:fructan fructosyl-transferase (FFT) activities from crude extracts of tuberous roots of Viguiera discolor growing in a preserved area of cerrado were analyzed in 1995-1996. SST activity was characterized by the synthesis of 1-kestose from sucrose and FFT activity by the production of nystose from 1-kestose. The highest fructan-synthesizing activity was observed during early dormancy (autumn), when both (SST and FFT) activities were high. The increase in synthetic activity seemed to start during the fruiting phase in the summer, when SST activity was higher than in spring. During winter and at the beginning of sprouting, both activities declined. The in vitro synthesis of high molecular mass fructans from sucrose by enzymatic preparations from tuberous roots collected in summer showed that long incubations of up to 288 h produced consistently longer polymers which resembled those found in vivo with respect to chromatographic profiles.