Avaliaram-se os efeitos da lactulose na saúde gastrointestinal de frangos de corte pela aferição do pH e enumeração de unidades formadoras de colônias (UFCs) de Salmonella Typhimurium e Escherichia coli no inglúvio e ceco de aves inoculadas experimentalmente, via oral, na dose de 5,0 X 102 UFC /0,5mL com Salmonella Typhimurium. O delineamento adotado foi o inteiramente casualizado, utilizando-se 630 pintos, machos, os quais foram distribuídos em seis tratamentos, com sete repetições e 15 aves por unidade experimental. O tratamento 1: grupo controle (placebo); tratamento 2: grupo que recebeu somente a lactulose na água; tratamento 3: grupo que recebeu somente Salmonella Typhimurium; tratamento 4: grupo que recebeu a lactulose e Salmonella Typhimurium simultaneamente no primeiro dia de vida [L (1d) + ST (1d)]; tratamento 5: grupo que recebeu a lactulose 48 horas antes de serem inoculadas com Salmonella Typhimurium [L (1d) + ST (48h)] e tratamento 6: grupo que foi inoculado com Salmonella Typhimurium no primeiro dia e 48 horas depois receberam a lactulose [ST (1d) + L (48h)]. Aos dias sete, 14, 21 e 28 uma ave por parcela foi sacrificada e os conteúdos do inglúvio e do ceco foram coletados para a aferição do pH e contagem de Salmonella Typhimurium e Escherichia coli. Constatou-se que a lactulose determinou redução nos valores (P<0,05) de pH nos conteúdos do trato digestório aos sete dias de vida, e esta redução se manteve até 28 dias somente para o inglúvio nos tratamentos que receberam a lactulose, independente do período de inoculação do patógeno. Verificou-se, também, que a lactulose reduziu (P<0,05) as UFCs de Escherichia coli e de Salmonella Typhimurium no inglúvio aos 21 e 28 dias de vida nos tratamentos em que se administrou a lactulose antes do patógeno. Pode-se concluir que a lactulose altera os valores de pH do inglúvio e reduza colonização de Salmonella Typhimurium no ceco e as UFCs de Escherichia coli no inglúvio em todo o período experimental.

This study was conducted to assess the effects of lactulose on the intestinal lumen by measuring the pH content of the gastrointestinal tract, and couting the colony forming units (CFU) of Escherichia coli and Salmonella Typhimurium in broilers experimentally and orally inoculated with Salmonella Typhimurium, at the dose of 5.0 X 102 CFU / mL 0.5. Birds were allotted in a completely randomized design, with 630 day-old male chicks distributed into six treatments, with seven replications and 15 birds per experimental unit. Treatment 1: group that did not receive microbial inoculum or lactulose (placebo group); treatment 2: group that received only lactulose (lactulose-L control group); treatment 3: group that received only Salmonella Typhimurium (ST-positive control group); treatment 4: group that received lactulose and Salmonella Typhimurium on the first day of life (L (1) + ST (1)); treatment 5: group that received lactulose 48 hours before the Salmonella Typhimurium (L (1) + ST (48h)); and treatment 6: group that received the Salmonella Typhimurium 48h before lactulose (ST (1) + L (48h)). At seven, 14, 21 and 28 days of age, one bird per plot was euthanized and cecum and crop contents were collected for counting of Salmonella Typhimurium and Escherichia coli. Furthermore, pH of crop and cecum were measured on for the same birds at seven, 14, 21 and 28 days of age, and blood was collected for liver enzyme evaluation. Lactulose reduced pH value (P<0.05) of digestive organs at seven days of life, and this reduction remained until 28 days only in the crop, regardless of the pathogen inoculation, whereas the cecal pH at 21 and 28 days, did not differ among the other treatments (P> 0.05). We also verified that lactulose reduced (P <0.05) the CFU of Escherichia coli and Salmonella Typhimurium in the crop at 21 and 28 days of age in the treatments in which lactulose was administered before the pathogen inoculation. Lactulose changed pH, except cecal pH, and reduced the colonization of Salmonella Typhimurium in the cecum and the number of UFCs of Escherichia coli in the crop during all experimental period.

The objective of this experiment was to evaluate the influence of lactulose on performance as well as its ability to prevent colonization by Salmonella Typhimurium in broilers orally inoculated with this pathogen. The design adopted was completely randomized, with 630 one-day-old male chicks distributed into six treatments, with seven replications and 15 birds per experimental unit. The treatments comprised the following procedures: T1 (control group) - no S. Typhimurium inoculation or supply of lactulosis; T2 - only inoculation of S. Typhimurium; T3 - only lactulosis supply; T4 supply of lactulosis and S. Typhimurium inoculation on the first day of life; T5 - supply of lactulosis 48 hours before S. Typhimurium inoculation; and T6 - supply of lactulosis 48 hours after inoculation of S. Typhimurium. Performance variables were evaluated on the seventh, 14th, 21st and 28th days of age; fragments of the duodenum and jejunum were collected and sent to histomorphometric assessment at 14 days of age, and S. Typhimurium excretion was verified in cloacal swabs on the 10th, 24th and 35th days of age. Performance data were analyzed by ANOVA and Tukey's test (5%) and fecal excretion data were assessed by non-parametric chi-square test. Better weight gain and feed conversion were observed in groups fed lactulosis with or without challenge of S. Typhimurium up to 21 days of age. Reduced duodenum villous height was verified on the 14th day in groups challenged with the pathogen. Reduction of S. Typhimurium fecal excretion was verified in broilers fed lactulosis from the first day of life on and 48 hours before receiving S. Typhimurium directly into the crop. Lactulosis increases broiler performance up to one week after its inoculation, influences duodenum villous height and reduces the fecal excretion of Salmonella Typhimurium.

An experiment with 630 one-day-old chicks experimentally inoculated with Salmonella Typhimurium was performed to evaluate the effects of an organic acid blend (benzoic, fumaric and 2-hydroxi-4-methylltio-butanoic - HMTBa) on intestinal health and performance. The experimental challenge with Salmonella Typhimurium occurred in two different routes of administration: via crop on the first day after hatching, and via feed, offered from seven to 14 days of age. These groups were treated with organic acids in a 3 × 2 (agent versus acid) factorial arrangement. Chicks treated with organic acids had higher weight gain, mean live weight and better feed conversion at 14 days of age, and higher weight gain at 28 days of age. Chicks treated with organic acids inoculated via crop had higher duodenum villi height than animals of the control group. Jejunum villi were higher in chicks of the negative control group compared with birds supplemented with organic acids. Small intestine pH in chicks of the inoculated group was lower compared with control group throughout the trial period. HMTBa acid in the dosage of 0.4% improves intestinal health and performance when nalidixic acid resistant Salmonella Typhimurium is experimentally inoculated.