Metabolomics by 1H-NMR and mineral content by ICP-OES for the spectroscopic characterization of rumen of dairy cows: an in vitro fermentation experiment.

Summary The aim of this thesis is to investigate the suitability of two techniques, Proton Nuclear Magnetic Resonance (1H NMR) and Inductively Coupled Plasma- Optical Emission Spectroscopy (ICP-OES) for the preliminary study of the effects of the administration of zootechnical bentonite, a mineral aflatoxins adsorbent, on the rumen metabolome of dairy cows. Clay minerals, such as bentonite, are added to animal feed because of their ability to absorb heavy metals and mycotoxins, and this practice has been linked to a wide variety of beneficial impacts, particularly on animal health and production. On the other hand, it appears that these substances can also cause adverse effects and can interact with the microbiota in the intestinal and ruminal tracts. The current study aims to evaluate the effects of varying doses of bentonite on ruminal fermentations, metabolomes, and mineral content during an in vitro fermentation experiment in order to draw conclusions about how these factors are affected. The addition of 0, 2.5, 5, 10, and 50 mg of bentonite (GLOBALFEED®T1) produced five treatment groups (B0, B50, B100, B200, B1000). For each treatment group, five independent samples were set up. Therefore, there were five different dosages of bentonite (0, 2.5, 5, 10, and 50 mg in a total volume of 150 mL) that were incubated at 39 ° C for 24 hours with 1 g of a dairy cow Total Mixed Ratio (TMR) and the ruminal fluid that was taken from a healthy Holstein cow. Proton (1H) Nuclear magnetic Resonance (NMR) spectroscopy and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) were used to analyze the metabolome and mineral content of the treated ruminal fluids, respectively, in pooled replicate samples to learn more about the effects of the bentonite treatment on ruminal fluid. Rumen fluid samples were collected from a health Holstein dairy cow from esophageal prob, frozen at -80 ° C, and analyzed using 1H-NMR spectroscopy and ICP-OES. The 1H-NMR study led to the identification of twenty distinct metabolites and revealed that the treatments resulted in clearly different rumen metabolic profiles for each bentonite dosage. According to the results of the ICP-OES analysis, the addition of bentonite changed the concentration of several elements, including Al, Ba, Ca, Cr, Mn, Mo, and Sr. It is possible that the administration of bentonite does not influence the gross fermentations that take place in the rumen, but it does appear to modify the ruminal metabolome and the concentrations of a few minerals, particularly butyrate and propionate in the ruminal fluid.