Since 2010, several duck Tembusu viruses (DTMUVs) have been isolated from infected ducks in China, and these virus strains have undergone extensive variation over the years. Although the infection rate is high, the mortality rate is usually relatively low—~5%–30%; however, since fall 2019, an infectious disease similar to DTMUV infection but with a high mortality rate of ~50% in goslings has been prevalent in Anhui Province, China. The present study identified a new Tembusu virus, designated DTMUV/Goose/China/2019/AQ‐19 (AQ‐19), that is believed to be responsible for the noticeably high mortality in goslings. To investigate the genetic variation of this strain, its entire genome was sequenced and analysed for specific variations, and goslings and mice were challenged with the isolated virus to investigate its pathogenicity. The AQ‐19 genome shared only 94.3%–96.9% and 90.9% nucleotide identity with other Chinese and Malaysian DTMUVs, respectively; however, AQ‐19 has high homology with Thailand DTMUVs (97.2%–98.1% nucleotide identity). Phylogenetic analysis of the E gene revealed that AQ‐19 and most of Thailand DTMUVs form a branch separate from any of the previously reported DTMUV strains in China. After the challenge, some goslings and mice showed typical clinical signs of DTMUV, particularly severe neurological dysfunction. AQ‐19 has high virulence in goslings and mice, resulting in 60% and 70% mortality through intramuscular and intracerebral routes, respectively. Pathological examination revealed severe histological lesions in the brain and liver of the infected goslings and mice. Taken together, these results demonstrated the emergence of a novel Tembusu virus with high virulence circulating in goslings in China for the first time, and our findings highlight the high genetic diversity of DTMUVs in China. Further study of the pathogenicity and host range of this novel Tembusu virus is particularly important.

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This study investigated the effects of Clostridium butyricum on the growth performance, meat quality and intestinal health of broilers. A total of 800 one-day-old male Arbor Acres broilers were randomly assigned to two groups with 16 replicates of 25 broilers per group and fed with a basal diet (CON) or a basal diet supplemented with 1.5 × 109 cfu/kg C. butyricum and 5 × 108 cfu/kg C. butyricum at 1–21 d and 22–42 d, respectively (CB). The results indicated that C. butyricum significantly increased the final body weight, average daily gain at 1–42 d in the growth performance of broilers (P < 0.05). Moreover, C. butyricum significantly increased a24h* value and pH24h value of breast meat but reduced the drip loss and shear force (P < 0.05). Regarding serum antioxidant indices, C. butyricum significantly increased the total superoxide dismutase (T-SOD) and total antioxidative capacity activities and reduced the malondialdehyde content (P < 0.05). Furthermore, the broilers in the CB demonstrated an increase in jejunal lipase and trypsin activities, villus height (VH) and VH-to-crypt depth ratio at 42 d compared with those in the CON (P < 0.05). C. butyricum also upregulated the intestinal mRNA levels of zonula occludens-1, nuclear factor erythroid 2-related factor 2 (Nrf2), SOD1 and interleukin-10 in the jejunal mucosa (P < 0.05), but it downregulated the mRNA levels of nuclear factor kappa B (NF-κB) and tumor necrosis factor-α (P < 0.05). These results indicate that C. butyricum can improve the growth performance and meat quality of broilers. In particular, C. butyricum can improve the intestinal health of broilers, which is likely to be related to the activation of the Nrf2 signaling pathway and inhibition of the NF-κB signaling pathway.

Simple Summary Weaning stress causes retarded growth, gut disorder and dysfunction, severe diarrhea and higher mortality in weaned piglets. Antibiotic growth promoters (AGP) have been conventionally used to alleviate the negative effects of weaning stress. However, the long-term use of AGP leads to various adverse effects, such as antimicrobial resistance and food drug residues, and threatens public safety. Therefore, AGP should be replaced with residue-free, pollution-free and toxin-free alternatives because several countries and regions have banned the use of AGP in the feed industry. This study investigates the effects of an encapsulated organic acid and essential oil mixture (OAEO) on the growth performance, immuno-antioxidant capacity and intestinal health of weaned piglets. The results reveal that OAEO as an alternative to AGP improved the growth performance, immuno-antioxidant status and intestinal health of weaned piglets partly by activating the Nrf2 signaling pathway and suppressing the TLR4/NF-κB signaling pathway. Abstract This study investigates the effects of an encapsulated organic acid and essential oil mixture (OAEO) on the growth performance, immuno-antioxidant capacity and intestinal health of weaned piglets. In total, 120 weaned piglets (23 days of age; 6.96 ± 0.08 kg) were randomly allotted to four treatments (six replicates/group; five piglets/replicate): the control group (CON) was fed the basal diet (BD), the antibiotic growth promoters group (AGP) received the BD with 20 mg/kg colistin sulphate and 10 mg/kg bacitracin zinc, and OAEO1 and OAEO2 were fed the BD with 1000 mg/kg and 2000 mg/kg OAEO, respectively. The trial lasted 21 days and then one piglet per replicate was selected for sample collection. OAEO increased the average daily gain, spleen index, serum interleukin (IL)-10, immunoglobulin (Ig) G and IgA levels; serum superoxide dismutase and glutathione peroxidase (GPX) activities; and jejunal villus height (VH), VH/crypt depth, goblet cell number, and amylase and trypsin activities ( p < 0.05) compared with CON but reduced the diarrhea rate, serum tumor necrosis factor (TNF)-α, malondialdehyde (MDA), and D -lactic acid contents and diamine oxidase (DAO) activity ( p < 0.05). OAEO also increased the jejunal zonula occludens-1, occludin, claudin-1, mucin-2, nuclear factor erythroid 2-related factor 2 (Nrf2), GPX and IL-10 mRNA levels, GPX activity and IL-10 content ( p < 0.05) compared with CON but reduced jejunal MDA, IL-1β and TNF-α contents and Toll-like receptor (TLR) 4, nuclear factor (NF)-κB and TNF-α mRNA levels ( p < 0.05). In addition, AGP increased ADG, serum IgA level and GPX activity, jejunal trypsin activity and IL-10 content and mRNA level ( p < 0.05) compared with CON but reduced the serum TNF-α content and DAO activity and jejunal NF-κB mRNA level ( ...