Dynamic impacts of public health events on price fluctuations in broiler industry Chain in China: Evidence from COVID-19 epidemic.

Using weekly data from January 2020 to December 2021 on the prices of various links in the Chinese broiler industry chain and the COVID-19 epidemic, we employed a time-varying parametric vector auto-regressive (TVP-VAR) model to investigate the dynamic effects of public health events on price fluctuations of upstream, midstream, and downstream products in the Chinese broiler industry chain. Our findings showed that the COVID-19 epidemic had different effects on the prices of various broiler products, both in direction and magnitude, at different lags and time intervals. Chicken and live chicken prices were impacted the most, followed by broiler chick prices, while broiler feed prices were impacted the least. The epidemic constantly impacted broiler chick and chicken prices, while its effect on live chicken prices was initially negative but turned positive afterwards. Additionally, the impact of the COVID-19 epidemic on broiler product prices consistently increased with more extended lag periods. The impulse responses at different epidemic time points were heterogeneous. With the results of this study, policy recommendations can be suggested to relevant government departments to optimize the prevention and control measures for public health emergencies and ensure price stability in the broiler industry.

A sensitive immunochromatographic assay using colloidal gold-antibody probe for rapid detection of fumonisin B1 in corn.

A sensitive immunochromatographic assay (ICA) using a colloidal gold-antibody probe for the rapid detection of fumonisin B1 (FB1) in corn samples was developed. The colour density of the test line correlated with the concentration of FB1 in the range 2-40 ng ml(-1) by the assay, and the detection limit for FB1 was 2 ng ml(-1). The linear range for FB1 was 50-1000 µg kg(-1), and the visual limit detection of the test was 1000 µg kg(-1) in corn samples. The ICA to detect FB1 is sensitive, specific and rapid. Specific anti-FB1 monoclonal antibody (mAb) and FB1-ovalbumin (FB1-OVA) conjugate antigen were prepared. FB1 mAb, labelled with colloidal gold, was used as the probe on the immunochromatographic strip. FB1-OVA and goat-anti-mouse IgG were coated onto a nitrocellulose (NC) membrane as test lines and control lines, respectively. FB1 in samples will competitively combines the FB1 mAb with the FB1-OVA in an NC membrane and the results are directly observed by the colour of the detection and quality control lines. The concentrations of FB1 mAb labelled with colloidal gold, detecting antigen and goat anti-mouse IgG, were optimised. The results indicate that the test strip is specific for FB1, with no cross-reactivity to other toxins. The strip assay for FB1 was simple, only needing one step without complicated assay performance and expensive equipment, and the total time for visual evaluation was less than 10 min. A survey of 24 corn samples from Hefei, China, was performed with the test strip and HPLC, and the detection results showed that the developed ICA and the HPLC were in excellent agreement. Hence, the developed ICA can be used as a method for rapid detection of FB1 in corn samples.