Cadmium chloride

Magnesium chloride hexahydrate (MgCl₂·6H₂O, 98%), calcium chloride (CaCl₂, 96%), manganese chloride tetrahydrate (MnCl₂·4H₂O, 99%), zinc chloride (ZnCl₂, 98%), cobalt chloride hexahydrate (CoCl₂·6H₂O, 99%), nickel chloride hexahydrate (NiCl₂·6H₂O, 98%), cadmium chloride (CdCl₂, 99%), copper chloride dihydrate (CuCl₂·2H₂O, 98%), stannic chloride pentahydrate (SnCl₄·5H₂O, 98%), 2-aminoethanol (HO(CH₂)₂NH₂, 99.9%), potassium hydroxide (KOH, 85%), and ethanol (C₂H₅OH, 99.7%) were obtained from Sinopharm Chemical Reagent Co. Ltd. Hydrogen hexachloroiridate (IV) hexahydrate (H₂IrCl₆·H₂O, 99%) was obtained from Alfa Aesar. Ferrous chloride tetrahydrate (FeCl₂·4H₂O) was obtained from Strem. Nafion solution (~5 wt.% in a mixture of lower aliphatic alcohols and water) was obtained from Sigma–Aldrich. The carbon powder (XC72R) was purchased from Vulcan. The deionized water (18 MΩ cm⁻¹) used in all experiments was prepared by passing water through an ultrapure purification system.

Cadmium chloride was of analytical grade and purchased from Sinopharm Chemical Reagents Co., Ltd. (Beijing, China). Stock solution (1 g/L Cd²⁺) was prepared with double-deionized water and stored at 4°C. The 5 or 10 μg/L Cd exposure solutions were prepared by adding 25 or 50 μL stock solution to 4.975 or 4.950 L double-deionized water during the experimental period.

PVA (hydrolysis degree: 88%; purity: 99%; molecular weight: 140,000 g mol⁻¹), copper chloride (purity: 99%), cadmium chloride (purity: 99%), and sodium silicate (purity measured as Na₂O, w%: 19.3–22.8%) were purchased from Sinopharm Chemical Reagent Co., Ltd., Shanghai, China. Oyster shells were obtained from Chengyang aquatic products wholesale market, Qingdao, Shandong Province, China.

Duodenal, jejunal, ileal, caecal, and colonic chyme were collected from 42-day-old broilers as samples (n = 6). Samples were weighed and diluted to a final concentration of 10% (W/V) with PBS (Gibco, New York, NY, USA). Then, 10% of intestinal slurry and 6 μg/mL ZEN were mixted with PBS 1:1 (the final concentration was 5% intestinal slurry with 3 μg/mL ZEN) under anaerobic conditions, then incubated anaerobically at 39 °C for 6 h. In the control group, cadmium chloride (10 mg/mL) (Sinopharm Chemical Reagent, Shanghai, China) was added to 10% sample slurries to inactivate the microorganisms for 30 min before the contents were incubated with ZEN. After the incubation, pre-cooled methanol was added to terminate the reaction, and the supernatant liquors were taken for testing.