The present study evaluated the effect of aflatoxin B1 and Eimeria vaccine challenges and their interaction on intestinal morphology, applying the morphometric index "I See Inside" (ISI). Immune cellular response and broiler chicken performance were also studied. A total of 240 broiler chickens were divided in a 2 × 2 factorial arrangement with 4 treatments, T1: Control diet and no challenge (CON), T2: Aflatoxin B1 (AFLA), T3: Control diet and Eimeria challenge (COC), and T4: Aflatoxin B1 and Eimeria challenge (AFLA+COC). The mathematical morphometric index ISI was applied to evaluate macro and microscopic alterations. Samples of liver and jejunum were analyzed for macrophages, CD4+, and CD8+ cells counting by immunohistochemistry at 7, 14, and 21 d of age. Chickens challenged with Eimeria presented higher ISI of macroscopic alterations associated to Eimeria lesion at the medium small intestine, lower body weight gain (BWG) and feed intake (FI), and worse feed conversion ratio compared to non-challenged birds. Both Eimeria and aflatoxin challenges modulated the immune cells in the jejunum and liver, generally increasing the number of macrophages, CD4+, and CD8+ cells in relation to the control group. Birds from COC and COC+AFLA groups presented higher ISI histological score in the jejunum at 7 and 14 d of age compared to the CON and AFLA groups. The reduction of FI and BWG was correlated to high histological ISI and resulted in a high presence of immune cells in tissues, suggesting immune response demand. The histological ISI had statistical correlation to broiler performance.

Highlights The ISI was applied to evaluate histologic alterations specific of Eimeria infection. The ISI histological score show high correlation with broilers performance. The higher the ISI scores the worse are the performance results of birds challenged.

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.

RESUMO.-Objetivou-se com o presente estudo comparar o efeito de diferentes sorovares de Salmonella na resposta imune local da mucosa do intestino de frangos de corte. Aos sete dias de idade, as aves foram desafiadas com os sorovares S. Enteritidis, S. Typhimurium, S. Senftenberg, S. Mbandaka e S. Minnesota. Foi observado que todos os sorovares testados foram capazes de colonizar o intestino das aves sendo possível o isolamento de Salmonella em suabes de cloaca, 48 h após inoculação. De maneira geral, as aves do grupo controle negativo, que não foram desafiados apresentaram quantidade significativamente menor de células imunológicas na mucosa intestinal do que as aves desafiadas. Porém, verificou--se que os sorovares de Salmonella, utilizados neste estudo, apresentaram diferentes efeitos sobre a dinâmica celular da mucosa do íleo e ceco e afetaram de modo diferente o ganho de peso e ganho médio diário das aves demonstrando distintos graus de patogenicidade. Os sorovares Enteritidis e Typhimurium apresentaram um efeito mais intenso tanto no desempenho quanto na mobilização de células imunoló-gicas na mucosa intestinal de frangos de corte. 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. Avaliação da resposta imunológica da mucosa intestinal

No abstract