Komala Arsi

Targeting motility properties of bacteria in the development of probiotic cultures against Campylobacter jejuni in broiler chickens.

Campylobacter is the leading cause of gastroenteritis worldwide. Campylobacter is commonly present in the intestinal tract of poultry, and one strategy to reduce enteric colonization is the use of probiotic cultures. This strategy has successfully reduced enteric colonization of Salmonella, but has had limited success against Campylobacter. In an effort to improve the efficacy of probiotic cultures, we developed a novel in vitro screening technique for selecting bacterial isolates with enhanced motility. It is proposed that motility-selected bacteria have the marked ability to reach the same gastrointestinal niche in poultry and competitively reduce C. jejuni. Bacterial isolates were collected from ceca of healthy chickens, and motile isolates were identified and tested for anti-Campylobacter activity. Isolates with these properties were selected for increased motility by passing each isolate 10 times and at each passage selecting bacteria that migrated the farthest during each passage. Three bacterial isolates with the greatest motility (all Bacillus subtilis) were used alone or in combination in two chicken trials. At day of hatch, chicks were administered these isolates alone or in combination (n=10/treatment, two trials), and chicks were orally challenged with a mixture of four different wild-type strains of C. jejuni (∼10(5) CFU/mL) on day 7. Isolate 1 reduced C. jejuni colonization in both of the trials (p<0.05). A follow-up study was conducted to compare isolate 1 subjected to enhanced motility selection with its nonselected form. A reduction (p<0.05) in Campylobacter colonization was observed in all three trials in the chickens dosed using isolate with enhanced motility compared to the control and unselected isolate. These findings support the theory that the motility enhancement of potential probiotic bacteria may provide a strategy for reduction of C. jejuni in preharvest chickens.

Trans-Cinnamaldehyde, Carvacrol, and Eugenol Reduce Campylobacter jejuni Colonization Factors and Expression of Virulence Genes in Vitro

Campylobacter jejuni is a major foodborne pathogen that causes severe gastroenteritis in humans characterized by fever, diarrhea, and abdominal cramps. In the human gut, Campylobacter adheres and invades the intestinal epithelium followed by cytolethal distending toxin mediated cell death, and enteritis. Reducing the attachment and invasion of Campylobacter to intestinal epithelium and expression of its virulence factors such as motility and cytolethal distending toxin (CDT) production could potentially reduce infection in humans. This study investigated the efficacy of sub-inhibitory concentrations (SICs, concentration not inhibiting bacterial growth) of three GRAS (generally recognized as safe) status phytochemicals namely trans-cinnamaldehyde (TC; 0.005, 0.01%), carvacrol (CR; 0.001, 0.002%), and eugenol (EG; 0.005, 0.01%) in reducing the attachment, invasion, and translocation of C. jejuni on human intestinal epithelial cells (Caco-2). Additionally, the effect of these phytochemicals on Campylobacter motility and CDT production was studied using standard bioassays and gene expression analysis. All experiments had duplicate samples and were replicated three times on three strains (wild type S-8, NCTC 11168, 81–176) of C. jejuni. Data were analyzed using ANOVA with GraphPad ver. 6. Differences between the means were considered significantly different at P < 0.05. The majority of phytochemical treatments reduced C. jejuni adhesion, invasion, and translocation of Caco-2 cells (P < 0.05). In addition, the phytochemicals reduced pathogen motility and production of CDT in S-8 and NCTC 11168 (P < 0.05). Real-time quantitative PCR revealed that phytochemicals reduced the transcription of select C. jejuni genes critical for infection in humans (P < 0.05). Results suggest that TC, CR, and EG could potentially be used to control C. jejuni infection in humans.

Application of β-Resorcylic Acid as Potential Antimicrobial Feed Additive to Reduce Campylobacter Colonization in Broiler Chickens

Campylobacter is one of the major foodborne pathogens that result in severe gastroenteritis in humans, primarily through consumption of contaminated poultry products. Chickens are the reservoir host of Campylobacter, where the pathogen colonizes the ceca, thereby leading to contamination of carcass during slaughter. A reduction in cecal colonization by Campylobacter would directly translate into reduced product contamination and risk of human infections. With increasing consumer demand for antibiotic free chickens, significant research is being conducted to discover natural, safe and economical antimicrobials that can effectively control Campylobacter colonization in birds. This study investigated the efficacy of in-feed supplementation of a phytophenolic compound, β-resorcylic acid (BR) for reducing Campylobacter colonization in broiler chickens. In two separate, replicate trials, day-old-chicks (Cobb500; n = 10 birds/treatment) were fed with BR (0, 0.25, 0.5, or 1%) in feed for a period of 14 days (n = 40/trial). Birds were challenged with a four-strain mixture of Campylobacter jejuni (∼106 CFU/ml; 250 μl/bird) on day 7 and cecal samples were collected on day 14 for enumerating surviving Campylobacter in cecal contents. In addition, the effect of BR on the critical colonization factors of Campylobacter (motility, epithelial cell attachment) was studied using phenotypic assay, cell culture, and real-time quantitative PCR. Supplementation of BR in poultry feed for 14 days at 0.5 and 1% reduced Campylobacter populations in cecal contents by ∼2.5 and 1.7 Log CFU/g, respectively (P < 0.05). No significant differences in feed intake and body weight gain were observed between control and treatment birds fed the compound (P > 0.05). Follow up mechanistic analysis revealed that sub-inhibitory concentration of BR significantly reduced Campylobacter motility, attachment to and invasion of Caco-2 cells. In addition, the expression of C. jejuni genes coding for motility (motA, motB, fliA) and attachment (jlpA, ciaB) was down-regulated as compared to controls (P < 0.05). These results suggest that BR could potentially be used as a feed additive to reduce Campylobacter colonization in broilers.

Sustainable Fish and Invertebrate Meals for Methionine and Protein Feeds in Organic Poultry Production1

SUMMARY Organic poultry production is based on ecological processes, such as nutrient cycling, and reduces the use of synthetic inputs. High‐quality protein feeds are needed to provide essential amino acids for poultry, particularly methionine. Although synthetic methionine is currently allowed in poultry feeding in the US organic program, sources that are natural are needed. Fishmeal is a high‐quality protein and contains methionine; however, fishmeal sources are limited and may not be sustainable or local. A possible source of fishmeal in the USA is Asian carp fishmeal. Asian carp have invaded the Mississippi river basin with negative impacts on native fish and riparian ecosystems, and harvesting the carp may be a management strategy to help control it. Additional options for high‐quality protein feeds include invertebrate meals from mass insect production, such as black soldier fly larvae, and worms. These can be raised sustainably for poultry feed by using crop by‐products, residues, or recycled food to reduce food waste. Alternative feeding methods may be helpful to utilize these innovative feeds. Alternative protein feeds can contribute to ecological poultry production and have an important role under certified organic standards.

Meat quality characteristics of fast-growing broilers reared under different types of pasture management: Implications for organic and alternative production systems (Part II)

SUMMARY Currently, there is little scientific information regarding the effect of differing housing types and production methods on the final quality of broiler meat. The purpose of this study was to evaluate meat quality characteristics of commercial fast‐growing broiler chickens when raised in portable vs. fixed housing, with or without access to pasture. Fast‐growing broilers are being grown by many small farm poultry producers due to their favorable attributes, including greater breast meat yields, a more uniform carcass, and higher feed efficiency than heritage or slower growing breeds. The pasture land used in this study closely matched the lands common to this local area. It was a pasture composed of a mix of tall fescue, Bermuda grass, and a lesser amount of legumes and forbs. The experiment had 4 treatment groups: (1) small, portable hoop houses with access to pasture, (2) small, portable hoop houses without access to pasture, (3) a fixed house with access to the outdoors, and (4) a fixed house without access to the outdoors. The study was conducted during spring and fall within the same yr to evaluate if any seasonal effects on carcass or meat quality were present. Overall, the access to pasture did not alter meat quality parameters such as moisture, protein, fat percentage, pH, color, texture, cooking loss, or shear energy when compared to birds without pasture access. Since forages contribute to the nutritive value of the meat and may help in reducing costs, the type and quality of forage choices in pastures are important considerations for these production methods and need to be explored further for pasture production systems.

Chapter 19 – Chemical Contamination of Poultry Meat and Eggs

Poultry products are one of the most important sources of protein food in the world. Even though it is considered a healthy meat type, there are wide concerns regarding chemical contamination in these products. This review will describe some potential chemical contaminants in poultry meat and eggs and briefly discuss the regulatory process used in the United States for the control of these contaminants as an example of prevention and control strategies used around the world.