Occurrence of Aflatoxin B_(1),deoxynivalenol and zearalenone in feeds in China during 2018-2020

Background:The current study was conducted to investigate the individual and combined occurrence of aflatoxin B_(1)(AFB_(1)),deoxynivalenol(DON)and zearalenone(ZEN)in feeds from various Provinces of China during 2018 to 2020.A total of 3,507 feed samples,including 2,090 feed ingredients and 1,417 complete feed samples,were collected from different areas of China for mycotoxins analysis.Results:The individual contamination of AFB_(1),DON and ZEN were present in more than 81.9%,96.4% and 96.9% of feed samples,respectively,with average concentration ranges of AFB_(1) between 1.2-27.4μg/kg,DON between 458.0-1,925.4μg/kg and ZEN between 48.1-326.8μg/kg.Notably,0.9%,0.5% and 0.1% of feed ingredients,and 1.2-12.8%,0.9-2.9% and 0-8.9% of complete feeds for pigs,poultry and ruminants with AFB_(1),ZEN and DON that exceeded China’s safety standards,respectively.Moreover,more than 81.5%of feed ingredients and 95.7% of complete feeds were co-contaminated with various combinations of these mycotoxins.Conclusion:This study indicates that the feeds in China were universally contaminated with AFB_(1),DON and ZEN during the past 3 years.These findings highlight the significance of monitoring mycotoxin contaminant levels in the domestic animal feed,and the importance of carrying out feed administration and remediation strategies for mycotoxin control.

Experimental study of ultrasonic atomizer effects on values of EC and pH of nutrient solution

The objectives of this research were to reveal how main working parameters of ultrasonic atomizers would influence key properties of the atomized nutrient solution in an aeroponics system.The Yamazaki tomato nutrient solution was selected as a nutrient example.Uniform design(UD)method U_(12)(12^(2)×13)was adopted to arrange the test.In this test,spraying time and interval time were taken as quantitative factors with 12 levels(10,20,30,40,50,60,70,80,90,100,110,and 120 min,respectively),and ultrasonic atomizer frequency was taken as qualitative factor with 3 conditions(28 kHz,107 kHz,1.7 MHz).Based on test data,two regression formulations used to predict the values ofΔEC,andΔpH of atomized Yamazaki tomato nutrient solution was established and inspected.The spraying interval time of ultrasonic atomizers had no significant effect on EC and pH of the atomized Yamazaki tomato nutrient solution;the ultrasonic atomizer frequency was more effective than spraying time on the values of EC and pH;the values of EC and pH became maximum at(f_(3),T_(1))=(1.7 MHz,120 min)and minimum at(f_(1),T_(1))=(28 kHz,10 min).It was concluded that the effect of high-frequency(1.7 MHz)ultrasonic atomizer on EC and pH of the Yamazaki tomato nutrient solution was beyond the standard value for tomato growth.Therefore,the high-frequency(1.7 MHz)ultrasonic atomizer is not suitable for aeroponics cultivation when using the Yamazaki tomato nutrient solution as aeroponics nutrient solution.