Use of Caprylic Acid in Broiler Chickens: Effect on Campylobacter jejuni

Dietary supplemental coated essential oils and organic acids mixture improves growth performance and gut health along with reduces Salmonella load of broiler chickens infected with Salmonella Enteritidis

BACKGROUND

Reducing Salmonella infection in broiler chickens by using effective and safe alternatives to antibiotics is vital to provide safer poultry meat and minimize the emergence of drug-resistant Salmonella and the spread of salmonellosis to humans. This study was to first evaluate the protective efficacy of feeding coated essential oils and organic acids mixture (EOA) on broiler chickens infected with Salmonella Enteritidis (S. Enteritidis, SE), and then its action mechanism was further explored.

METHODS

A total of 480 1-day-old Arbor Acres male chickens were randomly assigned into five treatments with six replicates, including non-challenged control fed with basal diet (A), SE-challenged control (B), and SE-infected birds fed a basal diet with 300 mg/kg of EOA (BL), 500 mg/kg of EOA (BM) and 800 mg/kg of EOA (BH), respectively. All birds on challenged groups were infected with Salmonella Enteritidis on d 13.  RESULTS: Feeding EOA showed a reversed ability on negative effects caused by SE infection, as evidenced by decreasing the feed conversion rate (FCR) and the ratio of villus height to crypt depth (VH/CD) (P < 0.05), obviously decreasing intestinal and internal organs Salmonella load along with increasing cecal butyric acid-producing bacteria abundance (P < 0.05). Moreover, supplemental different levels of EOA notably up-regulated claudin-1 (CLDN-1), occludin (OCLN), zonula occludens-1 (ZO-1), mucin-2 (MUC-2), fatty acid binding protein-2 (FABP-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), myeloid differential protein-88 (MyD88) and interleukin-6 (IL-6) mRNA levels in the ileum of the infected chickens after challenge, whereas down-regulated toll-like receptor-4 (TLR-4) mRNA levels (P < 0.05). Linear discriminant analysis combined effect size measurements analysis (LEfSe) showed that the relative abundance of g_Butyricicoccus, g_Anaerotruncus and g_unclassified_f_Bacillaceae significantly was enriched in infected birds given EOA. Also, phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis showed that alpha-linolenic acid metabolism, fatty acid metabolism and biosynthesis of unsaturated fatty acids were significantly enriched in the EOA group.

CONCLUSION

Our data suggest that the essential oils and organic acids mixture can be used as an effective strategy to ameliorate and alleviate Salmonella Enteritidis infection in broilers.

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Long-Term Grow-Out Affects Campylobacter jejuni Colonization Fitness in Coincidence With Altered Microbiota and Lipid Composition in the Cecum of Laying Hens

Campylobacter jejuni is one of the leading causes of gastrointestinal illness worldwide and is mainly transmitted from chicken through the food chain. Previous studies have provided increasing evidence that this pathogen can colonize and replicate in broiler chicken during its breeding; however, its temporal kinetics in laying hen are poorly understood. Considering the possible interaction between C. jejuni and gut microbiota, the current study was conducted to address the temporal dynamics of C. jejuni in the cecum of laying hen over 40 weeks, with possible alteration of the gut microbiota and fatty acid (FA) components. Following oral infection with C. jejuni 81-176, inocula were stably recovered from ceca for up to 8 weeks post-infection (p.i.). From 16 weeks p.i., most birds became negative for C. jejuni and remained negative up to 40 weeks p.i. 16S rRNA gene sequencing analyses revealed that most of the altered relative rRNA gene abundances occurred in the order Clostridiales, in which increased relative rRNA gene abundances were observed at >16 weeks p.i. in the families Clostridiaceae, Ruminococcaceae, Lachnospiraceae, and Peptococcaceae. Lipidome analyses revealed increased levels of sterols associated with bile acid metabolisms in the cecum at 16 and/or 24 weeks p.i. compared with those detected at 8 weeks p.i., suggesting that altered microbiota and bile acid metabolism might underlie the decreased colonization fitness of C. jejuni in the gut of laying hens.

Field Interventions Against Colonization of Broilers by Campylobacter

Poultry accounts for a high proportion of human campylobacteriosis cases, and the problem of Campylobacter colonization of broiler flocks has proven to be intractable. Owing to their broad host range and genetic instability, Campylobacter organisms are ubiquitous and adaptable in the broiler farm environment, colonizing birds heavily and spreading rapidly after introduction into a flock. This review examines strategies to prevent or suppress such colonization, with a heavy emphasis on field investigations. Attempts to exclude Campylobacter via enhanced biosecurity and hygiene measures have met with mixed success. Reasons for this are becoming better understood as investigations focus on houses, ventilation, biosecurity practices, external operators, and compliance, among other factors. It is evident that piecemeal approaches are likely to fail. Complementary measures include feed and drinking water treatments applied in either preventive or suppressive modes using agents including organic acids and their derivatives, also litter treatments, probiotics, prebiotics, and alterations to diet. Some treatments aim to reduce the number of Campylobacter organisms entering abattoirs by suppressing intestinal colonization just before slaughter; these include acid water treatment or administration of bacteriophages or bacteriocins. Experimental vaccines historically have had little success, but some recent subunit vaccines show promise. Overall, there is wide variation in the control achieved, and consistency and harmonization of trials is needed to enable robust evaluation. There is also some potential to breed for resistance to Campylobacter. Good and consistent control of flock colonization by Campylobacter may require an as-yet undetermined combination of excellent biosecurity plus complementary measures.

Influence of lauric acid on the susceptibility of chickens to an experimental Campylobacter jejuni colonisation

Among the organic acids, lauric acid has shown a high level of in vitro activity against Campylobacter jejuni. The prevalence and intensity of C. jejuni excretion at slaughter often becomes lower with increasing age. In higher-aged broilers on organic farms which often use other breeds, in turn, the prevalence of C. jejuni is sometimes higher at slaughter. The question then arises as to whether a diet with higher lauric acid concentrations, the age alone or the genetic breed might have an effect in the spread and intensity of an experimental C. jejuni infection in vivo. Therefore, two complete diets with or without 2% lauric acid from palm kernel fatty acids were offered to 450 chickens (ten subgroups à 15 birds, repetitions: n = 3) of two broiler and two layer breeds (Ross 308, Hubbard JA 757, Lohmann Dual and Lohmann Brown-Classic). All breeds were reared for 42 days, Lohmann Brown-Classic also for about 98 days. Twenty-one days before dissection, three seeder birds per subgroup were orally infected with a 1 mL inoculum of C. jejuni (4.46±0.35 log10 CFU/mL). Qualitative detection of C. jejuni in cloacal swabs was performed at days 2, 4, 7, 14 after inoculation and at dissection in all birds. Quantitative detection was performed on excreta samples of seeder birds at days 2, 11 and 17 after experimental challenge and on caecal samples of all birds at dissection. Two days after experimental inoculation, C. jejuni prevalence was higher in control birds without lauric acid supplementation (48.9% vs. 39.6%; P = 0.0462). Depending on age, two days after inoculation the C. jejuni prevalence in young Lohmann Brown-Classic chickens was significantly lower (37.8% vs. 61.1%) whereas at dissection it was higher (99% vs. 67%). At day 2 after inoculation C. jejuni counts in the excreta of young Lohmann Brown-Classic were lower in comparison to those in old ones (log10 CFU/g: 3.30±2.68 vs. 5.24±1.56). Eleven (log10 CFU/g: 5.14±1.13 vs. 4.16±0.82) and 17 days after inoculatioin (log10 CFU/g: 3.77±2.02 vs. 1.72±1.87) it was the reverse situation. At dissection, the carriage of C. jejuni in caecal content was higher in younger than in older birds (log10 CFU/g: 8.57±0.46 vs. 6.66±1.43). An effect of genetic breed on C. jejuni prevalence was seen at dissection, this being lowest in Lohmann Dual chickens (91% vs. 98.9% in other breeds). At d 17 after challenge, C. jejuni counts in the excreta of young Lohmann Brown-Classic were lower in comparison to Ross 308 and Hubbard JA 757 (log10 CFU/g: 3.77±2.02 vs. 5.21±0.85 and 5.62±0.90). Lohmann Dual chickens showed an intermediary excretion, this being only significant lower compared to Hubbard JA 757 (log10 CFU/g: 4.31±0.89). In summary, the effect of lauric acid is limited to the initial phase after experimental inoculation. A higher age at infection seems to lead to a more rapid limitation of the infection. The excretion of C. jejuni appears to decrease more rapidly in layer breeds than in broiler lines after experimental inoculation.