Effects of glyphosate residues and different concentrate feed proportions in dairy cow rations on hepatic gene expression, liver histology and biochemical blood parameters

Abstract

Glyphosate (GLY) is worldwide one of the most used active substances in non-selective herbicides. Although livestock might be orally exposed via GLY-contaminated feedstuffs, not much is known about possible hepatotoxic effects of GLY. As hepatic xenobiotic and nutrient metabolism are interlinked, toxic effects of GLY residues might be influenced by hepatic nutrient supply. Therefore, a feeding trial with lactating dairy cows was conducted to investigate effects of GLY-contaminated feedstuffs and different concentrate feed proportions (CFP) in the diets as tool for varying nutrient supply to the liver. For this, 61 German Holstein cows (207 ± 49 days in milk; mean ± standard deviation) were either fed a GLY-contaminated total mixed ration (TMR, GLY groups, mean GLY intake 122.7 μg/kg body weight/day) or control TMR (CON groups, mean GLY intake 1.2 μg/kg body weight/day) for 16 weeks. Additionally, both groups were further split into subgroups fed a lower (LC, 30% on dry matter basis) or higher (HC, 60% on dry matter basis) CFP resulting in groups CONHC (n = 16), CONLC (n = 16), GLYHC (n = 15), GLYLC (n = 14). Blood parameters aspartate aminotransferase, γ-glutamyltransferase, glutamate dehydrogenase, cholesterol, triglyceride, total protein, calcium, phosphorus, acetic acid and urea and histopathological evaluation were not influenced by GLY, whereas all mentioned parameters were at least affected by time, CFP or an interactive manner between time and CFP. Total bilirubin blood concentration was significantly influenced by an interaction between GLY and CFP with temporarily elevated concentrations in GLYHC, whereas the biological relevance remained unclear. Gene expression analysis indicated 167 CFP-responsive genes, while seven genes showed altered expression in GLY groups compared to CON groups. Since expression changes of GLY-responsive genes were low and liver-related blood parameters changed either not at all or only slightly, the tested GLY formulation was considered to have no toxic effects on the liver of dairy cows.

Subacute toxicity studies of meals prepared from genetically modified potato overexpressing the StDREB1 or the VvWRKY2 transcription factor in rats

“…These results are in accordance with those of Rhee et al ., 21 who demonstrated that the consumption of GMPs did not have negative effects on the fertility of rats. The absence of adverse effects in our study are consistent with those described in other studies in which processed GM crops with enhanced agronomic traits have shown the absence of clinical effects or histopathological abnormalities in the organs or tissues of animals 22‐37 . Other safety assessment studies of GMPs showed the absence of negative effects on rats 19,38,39 .…”

Indirect Effects of the Herbicide Glyphosate on Plant, Animal and Human Health Through its Effects on Microbial Communities

“…Residues of glyphosate and AMPA in plant products and water are taken up by animals and humans and largely (60-70%) excreted in their feces and urine (Bus, 2015;Faniband et al, 2021;Heymann et al, 2021;Niemann et al, 2015;von Soosten et al, 2016;FAO and WHO, 2016). Glyphosate was detected in the urine of up to 96% of farm animals, with a maximum of 164 μg/L (Krüger et al, 2014a;Krüger et al, 2014b;Schrödl et al, 2014).…”

“…In a feeding study with dairy cows, where glyphosatecontaminated feedstuffs (122.7 μg GL/kg BW for 16 weeks) were compared with control feed, no direct effects of glyphosate were detected on various blood and liver parameters (Heymann et al, 2021;Schnabel et al, 2020), as well as the general health condition of the cows (Schnabel et al, 2017). Nevertheless, long-term indirect health effects via changes in the microbiome have been documented (Gerlach et al, 2014;Krüger et al, 2013).…”

Glyphosate Contamination at Several Concentrations And Its Impact onChanges in Goat (Capra hircus) Organ Tissue

“…The preparation output was then documented and observed visually microscopically. Furthermore, microscopic analysis was carried out on the organ tissues of the flesh, stomach, kidneys, lungs, and liver to analyze the effect of exposure to glyphosate compounds (Heymann et al, 2021).…”

“…The liver is an important organ in xenobiotic detoxification (Peillex and Pelletier, 2020). Glyphosate administration in cattle feed with an average glyphosate intake of 122.7 µg/kg/ day for 16 days, affected the total blood blilirubin concentration levels (Heymann et al, 2021). The main function plays a role in determining the non-specific immune response of organisms and plays a role in adaptive or specific immune responses including T and B lymphocytes for defense from harmful pathogens (Jakab, 2015).…”