Behavior of Salmonella heidelberg and Salmonella enteritidis strains following broiler chick inoculation: evaluation of cecal morphometry, liver and cecum bacterial counts and fecal excretion patterns

Abstract

Over the years, Salmonella Heidelberg (SH) has gained prominence in North America poultry production and in the poultry production of other countries. Salmonella Heidelberg has been isolated and reported from poultry and poultry products in Brazil since 1962, whereas Salmonella Enteritidis (SE) has only emerged as a serious problem in poultry and public health since 1993. These strains of Salmonella can cause intestinal problems in newly hatched chicks, and infection may persist until adulthood. Upon slaughter of chickens, Salmonella can contaminate carcasses, a condition that poses a threat to human health. The aim of this study was to compare the fecal excretion of Salmonella Enteritidis and Salmonella Heidelberg in newly hatched chicks (orally inoculated with 10 5 ufc/mL each) until 20 days of age. In addition, the ratio of cecal villus height:crypt depth (morphometry) and liver and cecum cell counts was analyzed in chicks ranging from 0 to 3 days of age and infected with these two Salmonella strains. One hundred seventeen chicks were separated into one of three experimental groups: a control group, an SEinfected group and an SH-infected group. Eight chicks per group were euthanized at 6, 12 and 72 hours post-inoculation (pi) to allow for Salmonella isolation from the liver and cecum and for the collection of the cecum for villi and crypt analysis. Other birds were allowed to mature to 20 days of age and cloacal swabs were taken at 2, 6, 13 and 20 days pi to compare the fecal excretion of inoculated strains. TheSalmonella Enteritidis group had a higher number of cells excreted during the trial. Both strains were isolated from the liver and cecum by 6h pi. At 12h pi the Salmonella Heidelberg group had high cell counts in the cecum. No difference was found in liver cell counts. Both strains showed lower villus height:crypt depth ratio than the control group post-infection.

Evaluation of the effectiveness and safety of a genetically modified live vaccine in broilers challenged with Salmonella Heidelberg

“…The qualitative method was preferred to the quantitative method for spleen/liver analysis because many samples with low SH load would be considered negative as a function of the limit of the technique used (quantification only from 100 CFU/g). Normally for SH, the level of contamination in caecum is higher than in spleen/liver (Borsoi et al, 2011).…”

“…Studies examining experimental inoculation of birds have demonstrated that the behaviour of SH resembles that of Salmonella Enteritidis, which can generate bacteria counts in both the intestine (caeca) and the viscera (liver); additionally, the curve to quantify the positivity of the two analysed serotypes was almost identical 72 h after inoculation (Borsoi et al, 2011). For all analysis times, SH counts in the intestines exceeded those in the viscera.…”

Effect of Bio-Mos Utilization in Broiler Chick Diets on Performance, Microbial and Histological Alteration of Small Intestine and Economic Efficiency

“…Lactobacillus bacteria count within the total lactic acid bacterial counts were performed by the microscopic examination of all plate colonies using simple staining. For Salmonella and E. coil determination in samples, 1 mL of the previously prepared dilutions was spread on XLD agar (Borsoi et al, 2011) and Mac-Conkey agar (Difco) (Jang et al, 2007), respectively. Colonies were counted after aerobic incubation at 37°C for 48 h. The results were expressed as CFU per gram of Asian J.…”

“…For Salmonella spp. and E. coil determination in samples on XLD agar (Borsoi et al, 2011) and Mac-Conkey agar (Difco) (Jang et al, 2007), respectively. Colonies were counted after aerobic incubation at 37°C for 48 h. The results were expressed as log CFU per gram of wet contents weight.…”

Assessment of Benzophenanthridine and Protopine Alkaloids in Broiler Challenged and Not by Salmonella Heidelberg

“…However, it is important to emphasize that the serotypes evaluated in the studies of Pickler et al (2013) and Santiago et al (2014) were Enteritidis and Typhimurium, respectively, differently from the present study. Furthermore, according to Borsoi et al (2011), broilers challenged with Salmonella Heidelberg excrete less bacteria than those challenged with Salmonella Enteritidis. In addition, they present intermittent excretion of Salmonella Heidelberg (Borsoi, 2009), which may limit the efficiency of cloacal swabs as a diagnostic method …”