High Incubation Temperature and Threonine Dietary Level Improve Ileum Response Against Post-Hatch Salmonella Enteritidis Inoculation in Broiler Chicks

Abstract

This study assessed the effect of both embryonic thermal manipulation and dietary threonine level on the response of broilers inoculated with Salmonella Enteritidis, considering bacterial counts in the cecal contents, intestinal morphology, mucin and heat shock protein 70 gene expression, body weight and weight gain. Thermal manipulation was used from 11 days of incubation until hatch, defining three treatments: standard (37.7°C), continuous high temperature (38.7°C) and continuous low temperature (36.7°C). After hatch, chicks were distributed according to a 3x2+1 factorial arrangement (three temperatures and two threonine levels and one sham-inoculated control). At two days of age, all chicks were inoculated with Salmonella Enteritidis, except for the sham-inoculated control group. There was no interaction between the factors on any analyses. High temperature during incubation was able to reduce colonization by Salmonella Enteritidis in the first days, reducing both Salmonella counts and the number of positive birds. It also increased mucin expression and decreased Hsp70 expression compared with other inoculated groups. High temperature during incubation and high threonine level act independently to reduce the negative effects associated to Salmonella Enteritidis infection on intestinal morphology and performance, with results similar to sham-inoculated birds. The findings open new perspectives for practical strategies towards the pre-harvest Salmonella control in the poultry industry.

Intra-Amnionic Threonine Administered to Chicken Embryos Reduces Salmonella Enteritidis Cecal Counts and Improves Posthatch Intestinal Development

“…Dietary supplementation with both Thr and mannan oligosaccharide (MOS) [5] or only Thr [24] has been reported to decrease the number of Salmonella -positive animals and bacterial counts in the cecal contents, similar to the present finding with in ovo Thr supplementation. Some factors may have contributed to decreased Salmonella cecal counts in the Thr-administered group at 168-hour postinoculation (9 days of age).…”

“…These results might be associated with preserved intestinal mucosal integrity since the T-SE animals presented similar morphometry to unchallenged animals (T-SHAM and NT-SHAM), while chicks from nonsupplemented groups presented compromised mucosal integrity at all times evaluated (24, 96, and 168 hpi). Improved intestinal integrity was also observed in Salmonella -challenged chicks fed Thr in the diet [24]. These results indicate that in ovo Thr supplementation reduced the burden of Salmonella toxins in the gut of broiler chicks.…”

Antimicrobial peptide, cLF36, affects performance and intestinal morphology, microflora, junctional proteins, and immune cells in broilers challenged with E. coli

“…Chickens challenged with E. coli in the present study showed an upregulated expression of MUC2, which is in line with previous reports 43,44 . It was shown that the expression of MUC2 increased in the infectious challenge to secrete more mucin from goblet cells into the intestinal lumen to support the protective layer between the invading bacteria and the epithelial cells 45 . Adding AMP to the diet downregulated the expression of MUC2 in the jejunum of challenged chickens, which may be attributed to the significant inhibitory effect of cLF36 on E. coli colonization in the intestine (as described above), which is in agreement with previous observation 46 .…”

Effects of eggshell temperature pattern during incubation on primary immune organ development and broiler immune response in later life

“…At day 42 posthatch, no differences in NCD antibody titers or swelling reaction in the wattle to Phytohemagglutinin-P injection were found. Increasing incubator temperature by 1°C from day 10 of incubation onward compared with a constant incubator temperature of 37.8°C was found to increase mucin expression and reduce colonization of Salmonella Enteritidis in the cecal content of 10-day-old broilers when inoculated with Salmonella Enteritidis at 2 d posthatch ( De Barros Moreira Filho et al., 2015 ). Somewhat contradictory, the same thermal manipulation treatment by Oznurlu et al.…”