Manure application can spread antimicrobial resistance (AMR) from manure to soil and surface water. This study evaluated the role of the soil texture on the dynamics of antimicrobial resistance genes (ARGs) in soils and surrounding surface waters. Six dairy farms with distinct soil textures (clay, sand, and peat) were sampled at different time points after the application of manure, and three representative ARGs sul1, erm(B), and tet(W) were quantified with qPCR. Manuring initially increased levels of erm(B) by 1.5 ± 0.5 log copies/kg of soil and tet(W) by 0.8 ± 0.4 log copies/kg across soil textures, after which levels gradually declined. In surface waters from clay environments, regardless of the ARG, the gene levels initially increased by 2.6 ± 1.6 log copies/L, after which levels gradually declined. The gene decay in soils was strongly dependent on the type of ARG (erm(B) < tet(W) < sul1; half-lives of 7, 11, and 75 days, respectively), while in water, the decay was primarily dependent on the soil texture adjacent to the sampled surface water (clay < peat < sand; half-lives of 2, 6, and 10 days, respectively). Finally, recovery of ARG levels was predicted after 29–42 days. The results thus showed that there was not a complete restoration of ARGs in soils between rounds of manure application. In conclusion, this study demonstrates that rather than showing similar dynamics of decay, factors such as the type of ARG and soil texture drive the ARG persistence in the environment.
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Manure application can spread antimicrobial resistance (AMR) from manure to soil and surface water. This study evaluated the role of the soil texture on the dynamics of antimicrobial resistance genes (ARGs) in soils and surrounding surface waters. Six dairy farms with distinct soil textures (clay, sand, and peat) were sampled at different time points after the application of manure, and three representative ARGs sul1, erm(B), and tet(W) were quantified with qPCR. Manuring initially increased levels of erm(B) by 1.5 ± 0.5 log copies/kg of soil and tet(W) by 0.8 ± 0.4 log copies/kg across soil textures, after which levels gradually declined. In surface waters from clay environments, regardless of the ARG, the gene levels initially increased by 2.6 ± 1.6 log copies/L, after which levels gradually declined. The gene decay in soils was strongly dependent on the type of ARG (erm(B) < tet(W) < sul1; half-lives of 7, 11, and 75 days, respectively), while in water, the decay was primarily dependent on the soil texture adjacent to the sampled surface water (clay < peat < sand; half-lives of 2, 6, and 10 days, respectively). Finally, recovery of ARG levels was predicted after 29–42 days. The results thus showed that there was not a complete restoration of ARGs in soils between rounds of manure application. In conclusion, this study demonstrates that rather than showing similar dynamics of decay, factors such as the type of ARG and soil texture drive the ARG persistence in the environment.
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From PLoS website: In general, dietary antigens are tolerated by the gut associated immune system. Impairment of this so-called oral tolerance is a serious health risk. We have previously shown that activation of the ligand-dependent transcription factor aryl hydrocarbon receptor (AhR) by the environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects both oral tolerance and food allergy. In this study, we determine whether a common plant-derived, dietary AhR-ligand modulates oral tolerance as well. We therefore fed mice with indole-3-carbinole (I3C), an AhR ligand that is abundant in cruciferous plants. We show that several I3C metabolites were detectable in the serum after feeding, including the high-affinity ligand 3,3´-diindolylmethane (DIM). I3C feeding robustly induced the AhR-target gene CYP4501A1 in the intestine; I3C feeding also induced the aldh1 gene, whose product catalyzes the formation of retinoic acid (RA), an inducer of regulatory T cells. We then measured parameters indicating oral tolerance and severity of peanut-induced food allergy. In contrast to the tolerance-breaking effect of TCDD, feeding mice with chow containing 2 g/kg I3C lowered the serum anti-ovalbumin IgG1 response in an experimental oral tolerance protocol. Moreover, I3C feeding attenuated symptoms of peanut allergy. In conclusion, the dietary compound I3C can positively influence a vital immune function of the gut.
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Voor een efficiënte opfok van vleeskuikens, met behoud van gezondheid van mens en dier, moet aan de dieren een kwalitatief voer met daarin een hoogwaardige eiwitbron worden verstrekt. Om aan de vraag naar eiwit te voldoen, gebruikt men in de veevoederindustrie doorgaans soja. Sojaproductie gaat echter gepaard met een grote ecologische voetafdruk en de vraag naar meer duurzaam geproduceerde eiwitbronnen neemt toe. De meeste eiwitbronnen hebben echter een eiwitverteerbaarheid die lager is dan soja. Bij gebruik van deze bronnen vindt daardoor meer microbiële afbraak (eiwitfermentatie) in de dikke darm en blinde darmen plaats, wat resulteert in darmschade t.g.v. giftige afbraakproducten en bacteriële groei van Clostridium perfringens. Groei van Campylobacter spp. leidt tevens tot gezondheidsrisico voor de consument. Naast een duurzaam productieproces, moeten eiwitbronnen daarom ook een hoge eiwitverteerbaarheid hebben. Uit gesprekken die gevoerd zijn door onderzoekers van de HAS hogeschool met nutritionisten van Agrifirm, het Feed Design Lab (FDL) en leveranciers van eiwitbronnen en voederadditieven, blijkt de noodzaak tot investering in duurzame eiwitbronnen. Hiermee voldoet de veevoederindustrie ook in de toekomst aan de vraag naar hoogwaardige grondstoffen, die door vleeskuikensector, de consument en de maatschappij wordt gesteld. Kansrijke eiwitbronnen worden beoordeeld door bestaande kennis m.b.t. duurzaamheid van het productieproces te centraliseren en in-vitro verteerbaarheidsonderzoek uit te voeren. In dit project werken HAS hogeschool, Wageningen Universiteit (WUR), Agrifirm en FDL samen in een consortium. In een eerste werkpakket leidt literatuuronderzoek tot een selectie van kansrijke duurzame eiwitbronnen. In een tweede werkpakket wordt middels een Boisson-analyse de verteerbaarheid van deze eiwitbronnen bestudeerd. In een volgend project wordt met dierproeven het effect van de meest kansrijke eiwitbronnen op darmfunctie, -gezondheid en dierprestatie bestudeerd.
