M. C. Lourenço

Avaliação microbiológica, histológica e imunológica de frangos de corte desafiados com Salmonella Enteritidis e Minnesota e tratados com ácidos orgânicos

Two experiments were carried out to evaluate effectiveness of organic acids against Salmonella enterica enterica serovars Enteritidis (SE) and Minnesota (SM) in broilers. In the first experiment three treatments were evaluated: T1 - feeding with organic acids, T2 - feeding with organic acids and organic acids in drink water, and T3 - control group. All animals were oral challenged with SE. Organic acids in diet (T1) and organic acids in diet and drink water (T2) reduced the shadding of Salmonella in crop and cecum 7 days post challenged with SE and reduced the CD3+ cells in jejunal mucosa of broilers. In the second experiment four treatments were evaluated, T1 - control group, T2 - control group oral challenged with Salmonella Minnesota (SM); T3 - oral challenged animals with SM and treated with organic acids in diet; T4 - oral challenged animals with SM and treated with organic acids in diet and in drink water. Organic acids in diet (T3) and organic acids in diet and in drink water (T4) reduced the shadding of SM in crop of challenged broilers, 7 days post inoculation The use of organic acids in diet and in water was more effective to control SE than SM.

Avaliação da resposta imunológica da mucosa intestinal de frangos de corte desafiados com diferentes sorovares de Salmonella

The study was designed to compare the effect of different Salmonella serovars in immune response across the count of CD8+ cells, CD4+ cells, goblet cells and macrophages in the gut mucosa of broilers. During the experimental inoculation at 7 day-old were used Salmonella enterica subspecies enterica sorovars Enteritidis, Typhimurium, Senftenberg, Mbandaka and Minnesota. It was observed that all serovars tested were capable of contaminating the poultry being possible counts of Salmonella in cloacal swabs, 48 h after inoculation and into the crop and cecum, at 14 and 20 day-old. Serovars tested had different effects on broiler performance assessed at 20 days. In the mucosa of the ileum and cecum of broilers, it was observed that some of the serotypes increased CD8 + cells, CD4 + cells, goblet cells and macrophages compared to the negative control group both at 14 and at 20 day-old. S. Enteritidis and S. Typhimurium are the serovars that showed the more intense effect in live performance and in the immune system of birds showing pathogenic characteristic; generally the broilers of the negative control showed significantly less immune cells on the intestinal mucosa than broilers inoculated experimentally. However, it was found that the Salmonella serovars used in this study had different effects on the cellular dynamics of the mucosa of the ileum and cecum and differently affect weight gain and average daily gain of poultry showing different levels of pathogenicity.

Uso de probiótico sobre a ativação de células T e controle de Salmonella Minnesota em frangos de corte

Para avaliar o efeito do probiotico sobre a resposta imunologica de frangos de corte desafiados com Salmonella Minnesota (SM), 60 frangos foram divididos em tres grupos: CN- (controle negativo) aves que nao foram inoculadas com SM, CP- (controle positivo) aves inoculadas com SM e Probiotico- aves suplementadas na racao com probiotico composto de Lactobacillus acidophilus, L. plantarium, L. rhamnosus, L. bulgaricus, Enterococcus faecium, Streptococcus thermophilus e Bifidobacterium bifidum e desafiadas com SM. Aos 14 dias foi realizada a inoculacao com SM e aos 7 e 35 dias foram quantificadas celulas caliciformes, CD4+ e CD8+ na mucosa intestinal do ileo e ceco. Aves suplementadas com probioticos aos 7 dias de idade apresentaram aumento significativo (P≤0,05) de celulas caliciformes e CD4+ no ileo e de celulas CD8+ no ceco. Aos 35 dias houve aumento significativo (P≤0,05) das celulas CD8+ nas aves inoculadas do CN e Probiotico. A utilizacao de probioticos proporcionou reducao significativa (P≤0,05) da contagem de Salmonella sp.

Modelo de protocolo experimental para induzir, classificar e avaliar as enterites inespecíficas em frangos de corte

Varios fatores negativos podem afetar a saude intestinal de frangos de corte e reduzir o seu desempenho. Aditivos para alimentacao animal, chamados melhoradores de crescimento sao utilizados na producao de frangos para controlar os problemas intestinais. Entretanto, a dificuldade de se induzir enterites em condicoes experimentais torna dificil a avaliacao destes produtos. O objetivo deste estudo foi avaliar o melhor modelo experimental para induzir enterite em frangos de corte. Foram utilizados 192 pintinhos de corte, machos (Cobb 500®), divididos em esquema fatorial 2x4 (com boa ou baixa qualidade do oleo na dieta e com ou sem vacina contra coccidiose e doenca de Gumboro), com oito tratamentos. As aves foram alojadas em cama de maravalha, com agua e racao a vontade, e foram pesadas semanalmente. Nos dias 14, 21, 28 e 35, seis aves por tratamento foram abatidas para avaliacao de lesoes macroscopicas e microscopicas mediante a implementacao de um sistema padrao de classificacao de severidade das lesoes que considerou infiltracao linfocitica, morfologia dos enterocitos, edema intersticial e dilatacao dos vasos linfaticos na mucosa do intestino. Foi observado que frangos alimentados com gordura de baixa qualidade na racao apresentaram menor ganho de peso e maior severidade de lesoes histologicas em todos os segmentos intestinais. Estas lesoes foram mais severas em aves desafiadas com coccidiose e doenca de Gumboro. Estes resultados sugerem que a inclusao de gordura de baixa qualidade na racao, associada ao desafio com cocciciose no primeiro dia de vida e contra doenca de Gumboro no 16o dia, e o melhor protocolo para induzir enterite em frangos de corte em condicoes experimentais, e ainda que o sistema padrao de classificacao de severidade de lesoes intestinais foi adequado para avaliar as enterites em frangos de corte.

Effect of Feeding Bacillus subtilis Spores to Broilers Challenged with Salmonella enterica serovar Heidelberg Brazilian Strain UFPR1 on Performance, Immune Response, and Gut Health

Salmonellosis is a poultry industry and public health concern worldwide. Recently, Salmonella enterica serovar Heidelberg (SH) has been reported in broilers in Brazil. The effect of feeding a blend of three strains of Bacillus subtilis (PRO) was studied in broilers orally challenged (107 CFU/chick) or not with a SH isolated in south of Brazil (UFPR1 strain). Twelve male Cobb 500 broilers per pen were randomly assigned to six treatments in a 3 × 2 factorial experiment where PRO was added at 0, 250, or 500 g/ton of broiler feed and fed to either SH-challenged (SH Control, SH + PRO 250, and SH + PRO 500) or non-challenged birds (Control, PRO 250, and PRO 500). Broiler performance, histologic alterations in intestinal morphology, Salmonella quantification and immune cells counts in liver (macrophages, T CD4+ and T CD8+) were analyzed. Changes in the intestinal microbiota of broilers were also studied by metagenomics for Control, SH Control, SH + PRO 250, and SH + PRO 500 only. Feeding PRO at 250 or 500 g/ton reduced SH counts and incidence in liver and cecum at 21 days of age. It was observed that PRO groups increased the macrophage mobilization to the liver in SH-challenged birds (P < 0.05) but reduced these cells in the liver of non-challenged birds, showing an interesting immune cell dynamics effect. PRO at 250 g/ton did not affect gut histology, but improved animal performance (P < 0.05) while PRO at 500/ton did not affect animal performance but increased histologic alteration related to activation of the defense response in the ileum in SH challenged birds compared to control birds (P < 0.05). SH + PRO 500 group presented a more diverse cecal microbiota (Shannon–Wiener index; P < 0.05) compared to Control and SH Control groups; while SH + PRO 250 had greater ileal richness (JackkNife index) compared to Control (P < 0.05). PRO was effective in reducing Salmonella colonization in liver and cecum when fed at 250 or 500 g/ton to broilers inoculated with SH strain UFPR1. PRO promotes positive alterations in performance (at 250 g/ton), immune modulatory effect in the gastrointestinal tract, SH reduction, and intestinal microbiota modulation.