Effects of 5-hydroxytryptophan and m-hydroxybenzylhydrazine associated to Lactobacillus spp. on the humoral response of broilers challenged with Salmonella Enteritidis.

This study investigates the effects of different doses of serotonin, its precursor 5-hydroxytry-ptophan (5HTP), and m-hydroxybenzylhydrazine inhibitor (NSD1015), administered via intraperitoneal for 5 consecutive days, on behavior and average body weight of broilers. We also measured the humoral immune response and quantification of Salmonella Enteritidis in broilers chickens that received the drugs evaluated and a Lactobacillus pool. The study was divided into 3 experiments: Experiment 1--administration of pharmaceuticals with choice of dosage; Experiment 2--administration of pharmaceuticals and a Lactobacillus pool in birds that were not challenged with S. Enteritidis, and Experiment 3--administration of pharmaceuticals and a Lactobacillus pool in birds challenged with S. Enteritidis. The ELISA was used to scan dosages of intestinal IgA and serum IgY. We used colony-forming units to quantify S. Enteritidis. The concentrations of IgA and IgY did not show significant differences (P>0.05) in Experiment 2. In Experiment 3, NSD1015 associated with Lactobacillus determined higher IgA concentrations, promoting greater stimulus to the immune system than 5HTP. Regarding quantification of S. Enteritidis in the cecal content of birds, 5HTP associated to Lactobacillus determined the smallest number of bacteria, showing possible interaction of 5-hydroxytryptophan and Lactobacillus spp. with the immune system of broiler chickens.

Immune response of broiler chickens immunized orally with the recombinant proteins flagellin and the subunit B of cholera toxin associated with Lactobacillus spp.

This study investigated the immune response of broiler chickens with oral treatment of a Lactobacillus spp. pool (PL) associated with microencapsulated recombinant proteins flagellin (FliC) and the subunit B of cholera toxin (CTB). Immune responses were evaluated by measuring IgA from intestinal fluid, serum IgY, and immunostaining of CD8(+) T lymphocytes present in the cecum. The evaluations were performed on d 0, 7, 14, 21, and 28 posttreatment. A significant increase (P < 0.05) was observed in IgA levels in all immunized groups, especially 3 wk after immunization. Treatments 2 (recombinant CTB) and 3 (recombinant FliC+CTB) showed the highest concentrations. Similarly, serum concentrations IgY (µg/mL) increased along the experiment, and the means for treatments 2 and 3 showed significant differences (P < 0.05) compared with controls, reaching concentrations of 533 and 540 µg/mL, respectively. The number of CD8(+) T lymphocytes in all treatments greatly differed (P < 0.05) compared with the negative control at 21 d posttreatment. However, only treatment 2 (recombinant CTB), 4 (PL), and 5 (recombinant FliC+ recombinant CTB + PL) remained significantly (P < 0.05) different from the control at 28 d posttreatment. Thus, it is concluded that the microencapsulated recombinant proteins administered orally to broiler chickens are capable of stimulating humoral and cellular immune response, and the combinations of these antigens with Lactobacillus spp. can influence the population of CD8(+) T cells residing in the cecum.

Evaluation of in vitro and in vivo adhesion and immunomodulatory effect of Lactobacillus species strains isolated from chickens.

This study aimed to characterize the in vitro and in vivo adhesion and immunomodulatory effect of Lactobacillus strains isolated from chickens. Lactobacillus samples isolated from 65-wk-old birds were identified by PCR; their adhesion was evaluated in vitro via basement membrane-type cell matrix and in vivo through carboxyfluorescein succinimidyl amino ester staining inoculation in 1-d-old birds and duodenum, jejunum, ileum, and cecum collections at 1, 4, 12, and 24 h after inoculation. The 5 best adhesive samples at the in vitro test formed a pool for total IgA and IgG measurement in sera and intestinal fluid. The birds were divided into groups by inoculation scheme: group 1 was treated with a pool of Lactobacillus spp. at 2-d-old and challenged 1 d later with Salmonella Enteritidis and then treated again with a pool of Lactobacillus spp. at 4 d of age; group 2 was treated with a pool of Lactobacillus spp. at 2 and 4 d of age; group 3 was challenged with Salmonella Enteritidis at 3 d of age; and group 4 was a negative control. Collections were taken at 7, 14, 21, 28, and 35 d after the first inoculation. The results suggest that basement membrane matrix use represents an important technique for triage of samples for subsequent in vivo evaluation and that carboxyfluorescein succinimidyl amino ester staining is efficient for identifying this bacterial characteristic. The Lactobacillus-treated groups (1 and 2) presented the highest IgA concentrations at the end of the experiment (12,054.6 and 10,568.4 ng/mL, respectively). The group 2 IgG values in intestinal fluid exceeded those of the other 3 groups (P < 0.05), peaking at 6.419 ng/mL. In most serum collections, the Lactobacillus-treated groups (1 and 2) did not differ significantly in IgG concentrations (P > 0.05), whereas group 3 presented the highest concentration of this antibody. It is concluded that there was greater adhesion of strains in the cecum and an important correlation between in vitro and in vivo results. These results also suggest the immunomodulatory action of Lactobacillus spp. in the chicken.