Effects of Niacin on Resistance to Enterotoxigenic Escherichia coli Infection in Weaned Piglets.

Nicotinic acid (NA) has been used to treat different inflammatory disease with positive influence, the mechanisms by which NA exerts its anti-inflammatory effects remain largely undefined. Here we proposed a new hypothesis that NA manipulated endogenous antimicrobial peptides (AMPs) which contributed to the elimination of enterotoxigenic Escherichia coli (ETEC) K88, and thus affects the alleviation of inflammation. Therefore, an experiment in weaned piglets treated with 40 mg NA for 3 days before ETEC K88 challenge was designed to investigate the effects of NA on resistance to enterotoxigenic E. coli infection in weaned piglets. Twenty-four weaned piglets were randomly assigned to 1 of 4 treatments based on weight and sex. The control and NA treated groups were administered 20 mL normal saline or 20 mL NA solution. The K88 challenged and NA treated plus K88 challenged groups were administered 20 mL normal saline or 20 mL nicotinic acid solution once daily for 3 consecutive days. On the fourth day, the K88 and K88 + NA groups were treated with oral administration of 4 × 109 cfu/mL ETEC K88. The results showed that NA alleviated the clinical symptoms of weaned piglets infected with ETEC K88. NA significantly reduced the amount of ETEC K88 in the spleen and liver (P < 0.05). The intestinal morphological damage caused by ETEC K88 infection was alleviated by NA in weaned piglets. In addition, NA significantly alleviated the expression of inflammatory cytokine [Interleukin-6 (IL-6), Interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α)] in the serum and intestines of weaned piglets infected with ETEC K88 (P < 0.05). NA significantly increased the content of secretory IgA (SIgA) and the expression of antimicrobial peptides [porcine ß defensin-2 (pBD2), protegrin1-5 (PG1-5) and PR39] in intestines of weaned pigs. NA increased the diversity of microflora in colonic contents, while NA significantly reduced the relative abundance of Bacteroidetes, Bacteroidales, and Bacteroidia in weaned piglets infected with ETEC K88 (P < 0.05). Furthermore, the NA group significantly reduced the level of HDAC7 in jejunum (P < 0.05) and increased the level of SIRT1 in the colon compared with the Control group. Moreover, NA significantly increased the levels phosphorylation of histone H3 at Ser10 (pH3S10) in ileum and the levels of acetylation of lysine 9 on histone 3 (acH3K9) and acH3K27 in colon (P < 0.05) in weaned piglets infected with ETEC K88 (P < 0.05). In conclusion, NA can alleviate the clinical symptoms, the damage of intestinal morphology, and intestinal inflammation in weaned piglets infected ETEC K88 through enhancing the expression of endogenous AMPs by associating the histone acetylation modification.

Knowledge of Animal Welfare and Consumers' Behavioral Intentions in China: A Moderated Mediation Model of Product Cognition and Empathy.

As purchase power and consumption knowledge increase, consumers gradually demand safer and healthier products. Animal welfare is expected to be an important attribute of high-end food in the future and a major concern for the high-quality development of the livestock industry. The objective was to shed new light on our understanding of consumers' perceptions and behavioral intentions toward animal-friendly food. Using sample data of 1499 food consumers in Guangdong province, China, this study explored the role of product cognition and empathy in the relationship between consumers' knowledge and behavioral intentions. Results indicate that knowledge of animal welfare significantly influences consumers' behavioral intentions, and there is a mediating effect on cognition. Meanwhile, empathy moderates the relationship between product cognition and consumers' intentions to purchase or recommend animal-friendly products. Improving consumers' knowledge of animal welfare and cognitive levels of animal-friendly products may contribute to promoting animal-friendly product consumption and sustainable development of the livestock industry.

Buffalo-Origin Seneca Valley Virus in China: First Report, Isolation, Genome Characterization, and Evolution Analysis.

Pigs are the main host of Seneca Valley virus (SVV), previously known as Senecavirus A (SVA). Pigs affected by SVV have vesicles in the nose, hooves, and limp and may cause death in some severe cases. Occasionally, SVV has also been detected in mice, houseflies, environmental equipment, and corridors in pig farms. Moreover, it was successfully isolated from mouse tissue samples. In this study, an SVV strain (SVA/GD/China/2018) was isolated from a buffalo with mouth ulcers in the Guangdong province of China using seven mammalian cell lines (including BHK-21, NA, PK-15, ST, Vero, Marc-145, and MDBK). The genome of SVA/GD/China/2018 consists of 7,276 nucleotides. Multiple-sequence alignment showed that SVA/GD/China/2018 shared the highest nucleotide similarity (99.1%) with one wild boar-origin SVV strain (Sichuan HS-01) from the Sichuan province of China. Genetic analysis revealed that SVA/GD/China/2018 clustered with those porcine-origin SVV strains. To the best of our knowledge, this is the first report of SVV infection in buffalo, which might expand the host range of the virus. Surveillance should be expanded, and clinical significance of SVV needs to be further evaluated in cattle.

Rapid detection of porcine deltacoronavirus and porcine epidemic diarrhea virus using the duplex recombinase polymerase amplification method.

Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PDCoV) have emerged and spread throughout the porcine industry in many countries and are economically important pathogens causing diarrhea in sows and acute death in newborn piglets. Therefore, a sensitive diagnostic method would be beneficial for the prevention and control of PEDV and PDCoV infection. However, traditional detection methods have a number of drawbacks. This research aimed to establish a rapid detection method of duplex recombinant enzyme-mediated thermostatic amplification (RT-RPA) for PEDV and PDCoV. In this study, eight pairs of primers were designed for each virus according to the conserved domains of both PEDV and PDCoV from the NCBI Genbank, and one pair of primers was selected for each virus following the test results. After optimization of the reaction time, reaction temperature and primer concentration ratio, the duplex RT-RPA assay amplified a 226-bp fragment specifically for PEDV and a 321-bp fragment specifically for PDCoV. Meanwhile, the specificity and sensitivity of the primers and clinical samples were tested to verify the establishment of the RT-RPA method. The sensitivities of the duplex RT-RPA method for PEDV and PDCoV were 1 × 102 copies/µL. The results were consistent with PCR results and showed that a detection method for PEDV and PDCoV duplex RT-RPA was successfully established. In summary, the duplex recombinase polymerase amplification method could offer a promising alternative to the duplex RT-qPCR for detection of PEDV and PDCoV.

Detection and Genetic Characterization of Atypical Porcine Pestivirus in Piglets With Congenital Tremors in Southern China.

Atypical porcine pestivirus (APPV) is an RNA virus newly discovered from swine in Asia, Europe, and the Americas. This novel virus has been confirmed as the cause of congenital tremor (CT) in piglets, which causes extensive economic losses to the swine industry. To investigate the genetic diversity and evolutionary relationship of APPV in China, 83 piglet samples with severe CT clinical signs were obtained from 12 commercial swine farms in 3 provinces of Southern China. RT-PCR revealed that the positive rates of APPV were as high as 100% (12/12) for the swine farms and 90.4% (75/83) for the samples. Subsequently, 21 positive samples and 3 positive samples were selected for partial E2 gene and complete polyprotein gene sequencing, respectively. Phylogenetic analysis showed that 62.5% of the sequences belonged to a novel APPV clade provisionally named genotype 3, which showed 81.0-82.1% sequence identity to genotypes 1 and 2. Amino acid sequence alignment showed that E2 protein of genotype 3 has three specific mutation sites, namely I19V, Y82F, and N107G. The results of the present study demonstrate that a novel APPV subgenotype, which is widely distributed in severe CT clinical samples in Southern China, was genetically diverse. We advocate for the inclusion of genotype 3 during revision of the APPV typing method.