Campylobacter is one of the main bacterial pathogens that cause campylobacteriosis in the United States. Poultry is considered a major reservoir for the transmission of Campylobacter to humans.

Effects of the in ovo administration of two vitamin D₃ sources (vitamin D₃ (D₃) and 25-hydroxyvitamin D₃ (25OHD₃)) on the expression of D₃ activity- and immunity-related genes in broilers subjected to a coccidiosis infection were investigated. At 18 d of incubation (doi), five in ovo injection treatments were administrated to live embryonated Ross 708 broiler hatching eggs: non-injected (1) and diluent-injected (2) controls, or diluent injection containing 2.4 μg of D₃ (3) or 2.4 μg of 25OHD₃ (4), or their combination (5). Birds in the in ovo-injected treatments were challenged at 14 d of age (doa) with a 20× dosage of a live coccidial vaccine. At 14 and 28 doa, the expression of eight immunity-related genes (IL-2, IL-6, IL-10, TLR-4, TLR-15, MyD88, TGF-β4, and IFN-γ) and four D₃ activity-related genes (1α-hydroxylase, 25-hydroxylase, 24-hydroxylase, and VDR) in the jejunum of one bird in each treatment–replicate group were evaluated. No significant treatment effects were observed for any of the genes before challenge. However, at 2 weeks post-challenge, the expression of 1α-hydroxylase, TGF-β4, and IL-10 increased in birds that received 25OHD₃ alone in comparison to all the other in ovo-injected treatment groups. Additionally, the expression of 24-hydroxylase and IL-6 decreased in birds that received 25OHD₃ in comparison to those injected with diluent or D₃ alone. It was concluded that the in ovo injection of 2.4 μg of 25OHD₃ may improve the intestinal immunity as well as the activity of D₃ in Ross 708 broilers subjected to a coccidiosis challenge.

Journal of Animal Science and Technology (JAST) is a peer-reviewed, open access journal publishing original research, review articles and notes in all fields of animal science. Topics covered by the journal include: genetics and breeding, physiology, nutrition of monogastric animals, nutrition of ruminants, animal products (milk, meat, eggs and their by-products) and their processing, grasslands and roughages, livestock environment, animal biotechnology, animal behavior and welfare.

Campylobacter jejuni (C. jejuni) is the most common food-borne pathogen that causes human gastroenteritis in the United States. Consumption of contaminated poultry products is considered as the major source of human Campylobacter infection. An effective vaccine would be a promising alternative to antibiotic supplements to curb C. jejuni colonization in poultry gastrointestinal (GI) tract. However, the genetic diversity among the C. jejuni isolates makes vaccine production more challenging. Despite many attempts, an effective Campylobacter vaccine is not yet available. This study aimed to identify suitable candidates to develop a subunit vaccine against C. jejuni, which could reduce colonization in the GI tract of the poultry. In the current study, 4 C. jejuni strains were isolated from retail chicken meat and poultry litter samples and their genomes were sequenced utilizing next-generation sequencing technology. The genomic sequences of C. jejuni strains were screened to identify potential antigens utilizing the reverse vaccinology approach. In silico genome analysis predicted 3 conserved potential vaccine candidates (phospholipase A [PldA], TonB dependent vitamin B12 transporter [BtuB], and cytolethal distending toxin subunit B [CdtB]) suitable for the development of a vaccine. Furthermore, the expression of predicted genes during host-pathogen interaction was analyzed by an infection study using an avian macrophage-like immortalized cell line (HD11). The HD11 was infected with C. jejuni strains, and the RT-qPCR assay was performed to determine the expression of the predicted genes. The expression difference was analyzed using ΔΔCt methods. The results indicate that all 3 predicted genes, PldA, BtuB, and CdtB, were upregulated in 4 tested C. jejuni strains irrespective of their sources of isolation. In conclusion, in silico prediction and gene expression analysis during host-pathogen interactions identified 3 potential vaccine candidates for C. jejuni.

Antimicrobial resistance is a serious global public health concern that could endanger the efficacy of antibiotics used for the treatment of diseases in humans, animals, and plants. The objective of this study was to characterize the antimicrobial resistance (AMR) pattern of Salmonella strains isolated from different stages of both No-Antibiotics-Ever (NAE) and conventional integrated broiler complexes. ResFinder was used to identify AMR genes from whole genome sequences while the phenotypic resistance of 14 different antibiotics was determined using broth microdilution method. Odds ratio and 95 % confidence limits were calculated using multivariate logistic regression for different complexes and stages of broiler production (α = 0.05). The major AMR genes identified were aac(6')-Iaa, aph(6)-Id, aph(3″)-Ib, blaCARB-2, sul1, tet(A), tet(B), tet(G), floR, fosA7, gyrA, and parC. The phenotypic results showed that 58 % (49/85) of isolates were resistant to at least one antibiotic class (AOR), 24 % (20/85) of isolates were resistant to at least two or more classes of antibiotics (ATR) and 6 % (5/85) of isolates were multi-drug resistant (MDR). In terms of 14 different antibiotics tested, 41 %, 39 %, 6 %, 5 % and 2 % of isolates were resistant to sulfisoxazole, tetracycline, nalidixic acid, ampicillin and ciprofloxacin respectively. Interestingly, 80 % (32/40) of Kentucky isolates showed phenotypic resistance to either tetracycline or sulfisoxazole or both. In addition, the odds of ATR Salmonella detection were 7 times (1.37 - 43.45; 95 % CL) more likely in the isolates from NAE complex as compared to conventional broiler complex (p = 0.0233). Overall, drug-resistant Salmonella were present within and surroundings of poultry production and poultry product that could potentially contaminate the final raw product. It may lead to complicated antimicrobial therapy during foodborne infections in consumers.

The effects of the Marek’s disease vaccine (MDV) on the live performance, breast meat yield, and incidence of woody breast myopathy (WBM) of Ross 708 broilers were investigated when administered alone or in conjunction with in ovo and dietary supplemental 25-hydroxycholecalciferol (25OHD₃). At 18 d of incubation (doi), four in ovo injection treatments were randomly assigned to live embryonated Ross 708 broiler hatching eggs: (1) non-injected; (2) commercial MDV alone; or MDV containing either (3) 1.2 or (4) 2.4 μg of 25OHD₃. An Inovoject multi-egg injector was used to inject a 50 μL solution volume into each egg. The birds were provided a commercial diet that contained 250 IU of cholecalciferol/kg of feed (control) or a commercial diet that was supplemented with an additional 2760 IU of 25OHD₃/kg of feed (HyD-diet). In the growout period, 14 male broilers were placed in each of 48 floor pens resulting 6 replicated pens per in ovo x dietary treatment combination. Live performance variable were measured at each dietary phases from 0 to 14, 15 to 28, and 29 to 40 d of age (doa). At 14 and 40 doa, pectoralis major (P. major) and pectoralis minor (P. minor) muscles were determined for one bird within each of the six replicate pens. At 41 doa, WBM incidence was determined. No significant main or interaction effects occurred for WBM among the dietary or in ovo injection treatments. However, in response to in ovo 25OHD₃ supplementation, BW and BWG in the 29 to 40 doa period and BWG and FCR in the 0 to 40 doa period improved. In addition, at 40 and 41 doa, breast meat yield increased in response to in ovo and dietary 25OHD₃ supplementation. Future research is needed to determine the possible reasons that may have been involved in the aforementioned improvements.