Steamed bread is a traditional staple food of China. Replacing wheat flour (WF) with Tartary buckwheat is expected to improve the nutritional value of steamed bread. In this study, Tartary buckwheat flour (TBF), Tartary buckwheat bran flour (TBBF), and Tartary buckwheat core flour (TBCF) were prepared, their composition and physicochemical properties were compared. It was found that TBBF had higher protein and rutin contents, so its antioxidant activity and dough rheological properties were obviously superior to those of TBF and TBCF. When TBBF was mixed with WF, its weight proportion in the blend (W_bran) had a significant effect on the dough rheological properties. When W_bran was 30%, the dough had the optimal mixing tolerance, and when W_bran exceeded 30%, it caused dilution effect, weakening the gluten network. With the increase of W_bran, the color of the steamed bread developed by the TBBF–WF blend gradually darkened and yellowed, the specific volume declined, and its hardness, gumminess, and chewiness ascended gradually. The appropriate addition of TBBF (W_bran = 10% and 30%) was beneficial to cell diameter and volume of steamed bread, but the further rise of W_bran would destroy its gas retention ability. The predicted glycemic index (pGI) of steamed bread declined significantly with the increasing W_bran.

The purpose of this experiment was to study the design and modification of hapten molecules and artificial antigen molecules of deoxynivalenol (DON), and to compare the preparation and identification methods of four artificial antigens. According to the characteristics of the molecular structure of DON, four artificial antigen coupling methods were designed—namely, N,N′-carbonyldiimidazole (CDI), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC), isobutyl chloroformate (IBCF), and N-hydroxysuccinimide (NHS)—to prepare artificial antigens and detection antigens. Through ultraviolet (UV), infrared (IR), and SDS–polyacrylamide gel electrophoresis (SDS–PAGE), along with other physical and chemical identification methods and animal immunisation, the best artificial antigen coupling method was screened. The results showed that the CDI method achieved the best effect among the synthesis methods. The titre of anti-DON polyclonal antibody (pAb) produced by animal immunisation reached 1: (6.4 × 10³). The half inhibitory concentration (IC₅₀) was 47.75 ng/mL, the cross-reaction rate with 3-acetyldeoxynivalenol (3-AcDON) was slightly higher at 35.3%, and there was no cross-reaction with other compounds; therefore, four artificial antigens were successfully prepared by using the molecular structure of DON. Through identification, the CDI method was screened as the best artificial antigen synthesis method, with the highest DON pAb titre, the best sensitivity, and the strongest specificity. This will lay a solid antigenic foundation for the preparation of better anti-DON monoclonal antibodies (mAbs) in the future.

Porcine epidemic diarrhea virus (PEDV) is an important pathogen in swine, causing severe economic losses to the global swine industry. As a coronavirus, PEDV is prone to mutations and recombination. Therefore, characterizing circulating strains is essential for disease control. In this study, a PEDV strain (GD1) was isolated from diarrheic piglets in Guangdong Province, China, and identified by RT-PCR and immunofluorescence. Pathogenicity was evaluated in piglet challenge experiment. The results showed that GD1 strain could be stably passaged in Vero cells, forming syncytia. Phylogenetic analysis based on the complete genome and spike (S) gene both placed GD1 strain within the GIIc genotype. Amino acid sequence alignment of the S protein revealed multiple amino acid mutations in the neutralizing epitopes COE, SE16, and SS6 of GD1 strain compared with the classical vaccine strain CV777. Recombination analysis suggested that GD1 may be a novel recombination strain originating from strains SD2021 and GDS28, with the recombination breakpoint located in the ORF1a region. Pathogenicity assessment demonstrated that GD1 is highly virulent, inducing severe watery diarrhea and vomiting in newborn piglets within 24 h post-inoculation, and causing histopathological lesions characterized by intestinal villous atrophy and shedding. Immunohistochemistry confirmed that PEDV antigen was predominantly distributed in the villous epithelial cells of the small intestine. The successful isolation and characterization of the GD1 strain provide important viral resources for further research on the genetic evolution of PEDV and the development of matched vaccines.

Ochratoxin A (OTA) is a common fungal toxin contaminant in feed that is primarily produced by fungi belonging to the Aspergillus and Penicillium genera. In animal husbandry, the long-term ingestion of OTA-contaminated feed by animals can lead to severe consequences, such as reduced production performance, immunosuppression, and kidney and liver damage. Therefore, the development of efficient OTA detection technology is crucial for ensuring animal health and enhancing farming efficiency. This study aimed to design and modify the molecular structure of OTA, compare the preparation and identification of two artificial antigens, and select the optimal artificial antigen. Based on the molecular structure of OTA, the OTA hapten was activated via the N-hydroxysuccinimide active ester (NHS) method to generate an intermediate product known as OTA-carboxylic acid ester. This intermediate was subsequently conjugated with bovine serum albumin (BSA) via the coupling agents N, N′-dicyclohexylcarbodiimide (DCC) or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) to prepare new and effective artificial antigens. Additionally, ovalbumin (OVA) was used to prepare detection antigens. The structures of the prepared artificial antigens were physically and chemically characterized via instrumental analysis techniques such as ultraviolet (UV) and infrared (IR) spectroscopy. Mice were immunized with artificial antigens to explore their immunogenicity. The results revealed successful conjugation of both artificial antigens with molecular binding ratios of OTA to BSA of 10.88:1 and 7.84:1. The immunized mice exhibited corresponding responses, and the titers of the mouse polyclonal antisera (pAbs) reached 1:3.2 × 10 ³ , the OTA pAb that was prepared from two artificial antigens was able to recognize OTA with 100% accuracy. Among them, the mice immunized with the artificial antigen OTA-BSA (EDC) exhibited the best sensitivity, with a half-maximal inhibitory concentration (IC ₅₀ ) of 11.40 ng/mL. Although the cross-reactivity rates with ochratoxin B (OTB) and ochratoxin C (OTC) were relatively high at 86.69% and 62.02%, respectively, the cross-reactivity rates with other compounds were less than 0.3%. In conclusion, this study successfully prepared two artificial antigens and selected the OTA-BSA (EDC) group as the optimal artificial antigen via identification. These results provide the antigenic foundation for the preparation of OTA monoclonal antibodies (mAbs) and the establishment of immunological analysis methods.