Mycotoxin Occurrence in Feeds and Raw Materials in China: A Five-Year Investigation.

Mycotoxins are ubiquitously present in feeds and raw materials and can exert toxicity on animals and humans. Therefore, mycotoxin occurrence should be monitored. We report here a multi-mycotoxin survey of feed samples in China from 2017 to 2021. Concentrations of aflatoxins, trichothecenes type B, fumonisins, and zearalenone were determined in a total of 9392 samples collected throughout China. Regional differences and year-to-year variation of mycotoxin occurrence were also assessed in new-season corn. Generally, Fusarium mycotoxins were prevalent, while mycotoxin contamination in each feed commodity showed a distinct pattern, e.g., wheat and bran were typically affected by trichothecenes type B, peanut meals were highly susceptible to aflatoxins, and finished feeds exhibited a comparatively high prevalence of all mycotoxins. In new-season corn, trichothecenes type B and fumonisins were most prevalent, with positive rates of 84.04% and 87.16%, respectively. Regions exhibited different patterns of mycotoxin occurrence. The Anhui and Jiangsu provinces of East China exhibited a high prevalence and concentrations of aflatoxins with a positive rate and a positive average of 82.61% and 103.08 µg/kg, respectively. Central China obtained high fumonisins levels of 4707.84 µg/kg. Trichothecenes type B and zearalenone occurred more frequently in temperate regions of Northeast China, and their positive rates reached 94.99% and 55.67%, respectively. In these regions, mycotoxin concentrations in new-season corn exhibited pronounced year-to-year variations and this could be due to the unusual changes of rainfall or temperature during sensitive periods of corn growing. A large fraction of new-season corn samples contained multiple mycotoxins with two to three classes (75.42%), and the most frequently observed co-contaminants were the combination of trichothecenes type B and fumonisins (73.52%). Trichothecenes type B and zearalenone concentrations were highly positively correlated with a coefficient of 0.775. In conclusion, mycotoxins contamination and co-contamination of feeds are common. Mycotoxin contamination in new-season corn exhibited regional patterns and year-to-year variations, with climate and weather conditions as determinant factors.

Effects of feeding variable levels of mycotoxins with or without a mitigation strategy on growth performance, gut permeability, and oxidative biomarkers in nursery pigs.

The objectives were to determine how high levels (> 2.5 mg/kg diet) of deoxynivalenol (DON), in conjunction with other naturally occurring mycotoxins (MTX) would impact growth, intestinal integrity, and oxidative status, with or without a mitigation strategy, in nursery pigs. One-hundred and five pigs (5.5 ± 0.52 kg) were randomly allotted to 35 pens and fed dietary treatments for 45 d. Treatments were factorially arranged with the inclusion of MTX being low (L-MTX; < 1 mg/kg diet) or high (H-MTX; > 2.5 mg/kg diet) in combination with no mitigation strategy or the inclusion of a mitigation strategy (Biofix® Plus, BPL; 1.5 mg/kg diet). There was no interaction between MTX level and BPL inclusion on average daily gain (ADG) or gain to feed ratio (GF), (P > 0.10). Compared to pigs fed diets containing L-MTX, feeding pigs diets containing H-MTX decreased ADG and GF (P < 0.05). The addition of BPL had no effect on ADG (P > 0.10), but improved GF (P = 0.09). There was an interaction between MTX and BPL on average daily feed intake (ADFI), where the addition of BPL had no effect on ADFI of pigs fed L-MTX diets but improved ADFI of pigs fed H-MTX diets (P = 0.09). An interaction was detected between MTX and BPL on protein oxidation as measured by plasma protein carbonyls (PC, P = 0.01), where the inclusion of BPL decreased plasma PC in pigs fed H-MTX diets to a greater extent than pigs fed the L-MTX diets. There was no interaction between MTX and BPL, or an effect of MTX or BPL on DNA damage as measured by 8-hydroxy-2'dexoxyguanosine (P > 0.10). There was no interaction between MTX and BPL, or a BPL effect on lipid damage as measured by thiobarbituic acid reactive substances (TBARS, P > 0.10), but pigs fed diets containing H-MTX exhibited lower concentrations of plasma TBARS (P = 0.07) compared to pigs fed L-MTX diets. There was no interaction between MTX and BPL, or an effect of MTX or BPL on plasma lactulose and mannitol ratio as a measure of intestinal permeability (P > 0.10). In conclusion, feeding H-MTX decreased ADG and GF, decreased plasma TBARS, but did not affect plasma 8-hydroxy-2'dexoxyguanosine or plasma LM ratio. The inclusion of a mitigation strategy improved ADFI when pigs were fed H-MTX diets and improved GF regardless of MTX level. Addition of a mitigation strategy also reduced plasma protein damage but did not affect indicators of DNA or lipid damage or affect gastrointestinal integrity.

[Investigation of potential causes for the development of porcine ear necrosis: different study designs--comparable results?]. / Untersuchung möglicher Ursachen von Ohrrandnekrosen: unterschiedliche Studien- designs--vergleichbare Resultate?

During the last years two studies for the investigation of the etiology of porcine ear necrosis were carried out at the Clinic for Swine of the University of Veterinary Medicine Vienna. In study 1, parameters, which are discussed in this context, were collected by veterinary practitioners by completing specially designed questionnaires in farms with symptoms of the porcine ear necrosis syndrome. In study 2, samples of piglets and feed were collected for laboratory analysis of the most important infectious agents as well as mycotoxins. In the present manuscript, the results of both projects were compared. Even if the selection criteria of both studies differed, the affected age class was comparable (5.5 to ten weeks of life in study 1 and six to ten weeks of life in study 2). The herd-specific prevalence of the porcine ear necrosis syndrome varied considerably with percentages between 2 and 10, respectively, to 100%. The evaluation of questionnaires in study 1 showed that 51% of the farms had problems with cannibalism. Particles of plant material, which were frequently seen on the histologic slides of study 2, could have got into the tissue by chewing the ears of the pen mates or cannibalism. Whereas in study 1 the negative effect of parameters as high pig density, suboptimal climate, missing enrichment material and bad quality of feed and water were considered, in study 2 all these factors were checked at sample collection and ruled out as precursor for cannibalism. In both studies bacterial agents proved to be a crucial co-factor for the expansion of the necroses to deeper tissue layers, whereas viral pathogens were classified less important. In both projects it was not possible to estimate the direct impact of infectious agents and mycotoxins as direct trigger of the necroses as well as their participation as co-factors or precursor in the sense of an immunosuppression or previous damage of blood vessels or tissue.