Chitosan Supplementation Reduces Enteric Colonization of Campylobacter jejuni in Broiler Chickens and Down-Regulates Expression of Colonization Genes

Abstract

Campylobacter is one of the leading causes of foodborne bacterial gastroenteritis worldwide, and poultry is considered as the most common source of human infections. Campylobacter is prevalent in most poultry flocks and a reduction of Campylobacter in poultry would greatly reduce the risk of campylobacteriosis in humans. Unfortunately, efforts to reduce Campylobacter in pre-harvest poultry have been met with limited success. Preliminary studies with the natural compound, chitosan, demonstrate its ability to kill Campylobacter, in vitro. The purpose of this study was to determine the ability of feed supplemented chitosan to reduce enteric Campylobacter colonization in broiler chickens. Additionally, the effect of chitosan on expression of Campylobacter's chicken colonization genes was investigated using real-time quantitative PCR (RT-qPCR). Because chitosan's antimicrobial properties may vary depending upon its molecular weight, selected doses of three molecular weight chitosans were supplemented in the feed and evaluated for efficacy to reduce Campylobacter in chickens. Three replicate trials were conducted, and in each trial, birds were divided into 10 treatments (n=10 birds/treatment) and were fed 0% (controls), 0.25%, 0.5% or 1% (wt./wt.) of a low, medium or high molecular weight chitosan. Birds were fed treated feed for the duration of the study and orally challenged with a four-strain mixture of wild type C. jejuni on day 6. On day 15, the ceca samples were collected for enumeration of Campylobacter. In all three trials, the 0.5% dose of the medium molecular weight chitosan reduced cecal Campylobacter counts (P<0.05). RTqPCR analysis revealed that chitosan down-regulated the expression of chicken colonization genes as compared to control (P<0.05). These results suggest that supplementation of chitosan in feed is a potential strategy to reduce the enteric colonization of Campylobacter in pre-harvest chickens.

On farm interventions to minimiseCampylobacterspp. contamination in chicken

“…counts in broiler chickens. In addition, RT-qPCR analysis revealed that chitosan down-regulated the expression of chicken colonisation genes when compared to a control (Arambel et al 2015). This suggested that chitosan supplementation could be a potential strategy to reduce the enteric colonisation of Campylobacter spp.…”

Prebiotic and Probiotic Approaches to Improving Food Safety on the Farm and Their Implications on Human Health

“…Most commonly, Campylobacter has been linked to poultry products and linked to human cases of gastroenteritis in most cases as well as the Guillain-Barré syndrome, reactive arthritis, and irritable bowel syndrome or inflammatory bowel disease in the most severe cases [16,17]. Campylobacter is a major concern for infection in poultry production [16][17][18]. One route of contamination, also common to most other pathogens, is through livestock water sources [19].…”

“…The use of prebiotics is most often seen coupled with a complementary probiotic (often described as "synbiotics"), and recent research has demonstrated the benefits that may exist with the coordinated use of such a complementary intervention. A list of the prebiotics identified for pathogen reduction in the literature is presented in As previously discussed, Campylobacter is among the leading foodborne pathogenic bacteria found in livestock and the majority of bacteria are introduced into the human food chain via poultry [16,17]. In an evaluation of Campylobacter colonization in hatchling chicks, chitosan (a compound from the chitinous shells of crabs and shrimp) was shown to reduce the population of C. jejuni both in vitro and in vivo when added to the feed [16].…”

“…A list of the prebiotics identified for pathogen reduction in the literature is presented in As previously discussed, Campylobacter is among the leading foodborne pathogenic bacteria found in livestock and the majority of bacteria are introduced into the human food chain via poultry [16,17]. In an evaluation of Campylobacter colonization in hatchling chicks, chitosan (a compound from the chitinous shells of crabs and shrimp) was shown to reduce the population of C. jejuni both in vitro and in vivo when added to the feed [16]. This reduction of colonization was attributed to a down-regulation of fliA, motA, motB, and CadF genes, which are all involved in the synthesis and function of the flagella used in cellular function and movement [16].…”

“…In an evaluation of Campylobacter colonization in hatchling chicks, chitosan (a compound from the chitinous shells of crabs and shrimp) was shown to reduce the population of C. jejuni both in vitro and in vivo when added to the feed [16]. This reduction of colonization was attributed to a down-regulation of fliA, motA, motB, and CadF genes, which are all involved in the synthesis and function of the flagella used in cellular function and movement [16].…”