The mite Psoroptes cuniculi is globally widespread and has a serious impact on commercial rabbit breeding. In China, diagnosis of P. cuniculi is currently based on conventional clinical methods that entail numerous disadvantages, including their failure to diagnose subclinical infections. Hence, alternative measures are required, and dot-ELISA is one of the most promising strategies. We cloned and expressed the recombinant P. cuniculi troponin C gene for use as a basis for novel dot-ELISA assay to detect P. cuniculi infections in rabbits. This amplified sequence encoded a 153 amino acid protein of 17·6 kDa and theoretical pI 4·18 without signal peptide. The recombinant troponin C of P. cuniculi is an outer membrane protein and may also be a new P. cuniculi allergen. Results of dot-ELISA test showed that this novel assay had more than 90% sensitivity but low specificity in distinguishing infections with P. cuniculi or Sarcoptic scabiei, despite very high agreement between observers (97-99%; κ values ranged from 0·95 to 0·98 for inter- and intra-observer variability test). This study showed that this novel method, at present, lacks diagnostic utility. Therefore, although simple serological assays such as dot-ELISA show great promise as diagnostic tools, we suggest that troponin C is not a suitable diagnostic antigen candidate.

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Alpha-ketoglutarate (AKG) is important for improving intestinal and systemic immune function. This study aimed to explore whether AKG enhances gut immunity in lipopolysaccharide (LPS)-challenged piglets by modulating the immune-related Th17/Treg balance pathway. A 2 × 2 factor design was used on 24 pigs, with the major factors being diet (basal diet or 1% AKG diet) and immunological challenge (saline or LPS). Piglets were fed with a basal or AKG diet for 21 d and then received intraperitoneal injection of LPS or saline. The results demonstrated that AKG supplementation enhanced growth performance compared with the control group (P < 0.05). Alpha-ketoglutarate improved the ileal morphological structure (P < 0.01). Finally, AKG supplementation increased interleukin (IL)-10, transforming growth factor beta-1, forkhead box P3, and signal transducer and activator of transcription 5 genes expression whereas decreasing IL-6, IL-8, IL-1β, tumor necrosis factor-α, IL-17, IL-21, signal transducer and activator of transcription 3 and rar-related orphan receptor c genes expression (P < 0.05). These findings suggested that dietary AKG can improve the growth performance of piglets. Meanwhile, dietary AKG can alleviate LPS-induced intestinal inflammation through Th17/Treg immune response signaling pathway.

The mite Psoroptes cuniculi is globally widespread and has a serious impact on commercial rabbit breeding. Current treatment methods are based on chemotherapy. Because of the disadvantages of these methods, alternative measures are required, and vaccination is one of the most promising strategies. Here, we cloned and expressed the recombinant P. cuniculi actin gene (rPc-act). Antiserum levels against rPc-act in rabbits were used to locate actin distribution in mite sections. Challenge trials were carried out to evaluate the immunity protection of rPc-act in rabbits, with antibody levels determined by ELISA. Sequence analysis of this gene fragment showed 89·26% and 84·91% identity to Sarcoptes scabiei and Mayetiola destructor sequences, respectively. Immunohistochemistry showed rPc-act to locate widely throughout the mites, especially in feet and muscle tissues. Recombinant P. cuniculi actin with QuliA adjuvant was used to immunize six rabbits. Each animal was challenge-infested with 25-50 adult mites. Although IgE levels showed no significant difference to controls, IgG levels were significantly higher, and clinical development showed no significantly different severity of lesions in vaccinated rabbits than in the controls. This study showed that rPc-act is a muscular isotype actin and has no clinical protective efficacy against P. cuniculi.