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Untersuchungen zum Stoffwechsel von Aminen und Polyaminen bei Einsatz von Grassilagen mit unterschiedlichen Reineiweißgehalten unter Zulage von Soja im Pansen in vitro
| Content Provider | Semantic Scholar |
|---|---|
| Author | Thomsen, Anna |
| Copyright Year | 2018 |
| Abstract | Evidences suggest that feeding grass silages low in the ratio of true protein in total crude protein (< 50 % TP/CP) is a nutrient factor of an unspecific health threatening disease called “Faktorenerkrankung Milchviehherde” in dairy cows since 2005. The early addition of soy protein helped to prevent severe propagation of the disease. Previous investigations about the fermentation of grass silages low in true protein in the in vitro system of the rumen called RUSITEC led to increased levels of secondary plant metabolites and free amino acids. In these investigations they could also determine a shift in ammonia, in branched short chain fatty acids (BSCFA), in gaseous volumina and composition as well as in the rumen microbiome. This study was conducted to investigate the metabolism of amines and especially polyamines in the RUSITEC-system when feeding grass silages of a TP/CP ratio less than 50 % and the influence of the addition of soy protein. Therefore, eight digestive experiments lasting 28 days each in the RUSITEC-system containing six fermenters were completed. Both types of grass silages (low: 50 % in TP/CP ratio) were collected from the same cultivated pastureland of two different dairy farms in northern Germany, minimizing the botanical influence. Two blocks of digestive experiments were performed (L31–L34: dairy farm A and L35–L38: dairy farm B). Corn starch was added for energy to all six fermenters of the RUSITEC. After the first eight days to initiate a balanced fermentation while feeding control grass silage, four fermenters were replaced with test grass silage (< 50 % TP/CP) of which two were supplemented with soy protein. This experimental stage lasted for ten days. In the final recovery stage from day 20–28 control grass silage was added again to all fermenters. Amines and polyamines and corresponding amino acids were analyzed using a liquid chromatography system linked to a mass spectrometry detector (LC-MS/MS). A new method without derivatization was developed on basis of HAKKINEN et al. (2007) to determine the soluble amines and polyamines cadaverine, putrescine, spermidine, spermine, β-Alanine, GABA and m/z 173 (possibly thermospermine) as well as the corresponding amino acids in the liquid and solid phase of the RUSITEC samples. Ammonia was measured via ammonia electrode and BSCFA were detected by gas chromatography. The results of the experimental stage in the liquid fermentation samples of the RUSITEC showed lower levels of amines in test fermenters compared to the control fermenters (-13.5 % to -60.3 %) except for cadaverine and GABA. In the first block cadaverine and GABA had also lower levels (-13.2 % and -36.1 %, resp.) whereas the second block had positive deviations in test fermenters vs. control fermenters (+9.8 % and +127 %, resp.). The corresponding amino acids had higher amounts in fermenters fed with test grass silage compared to control (between +1.6 % and +25.4 %). The solid RUSITEC samples were collected from the feeding bags after 48 hours of incubation. Lower analogous amine levels were noted as well during the experimental period (-7.8 % to -43.9 %). A different result was found for cadaverine in test fermenters leading to very little positive deviations from control fermenters (+1.8 % to +3.7 %), whereas β-Alanine and m/z 173 (possibly thermospermine) had contrary results. The first block (L31–L34) had +9.3 % and -48.2 % for β-Alanine and m/z 173 in test fermenters in comparison to control fermenters and the second block (L35–L38) had -44.3 % and +14.6 % respectively. Another exclusion was notable in the results of GABA which were positive throughout both blocks in solid samples, but in the second block even higher (L31–L34: +33.3 % and L35–L38: +88.7 % resp.). The corresponding amino acids tended to have negative deviations (-11.8 %), except for L-arginine (+4.6 to +54.3 %). L-lysine in test fermenters had contrary results again noting -86,6 % in the first and +82,1 % in the second run compared to control fermenters. The addition of soy protein did not reveal significantly different results in amines and polyamines. Ammonia and BSCFA were higher in test fermenters compared to control fermenters and soy protein addition resulted in significantly higher levels for those parameters. Summarizing all findings, it is obvious that feeding grass silages of TP/CP ratios < 50 % results basically in lower levels of amines and polyamines and higher amounts of free amino acids. We were able to show a connection between amino acids and amines and especially polyamines in the RUSITEC system with regard to their fast and complex metabolism and the wide range of influences. The results of ammonia and BSCFA could be explained by a shift in the rumen microbiome. The positive effect of the addition of soy protein in dairy herds could not be explained, but increased BSCFA and ammonia in test fermenters added with soy protein are supposed to be promotional to the deaminating bacteria Megasphaera elsdenii and HAP-Species. This still needs to be confirmed in further investigations. Main point of the investigations was to evaluate the reactivity and toxicity of long chained amines in cattle. Since the amounts of polyamines analyzed in the RUSITEC system were relatively small, a toxic potential of polyamines when feeding grass silages low in true protein is not assumed. Still pending is the potential feature of polyamines to build harmful complexes in the rumen and their influence on the dairy herd health. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://elib.tiho-hannover.de/servlets/MCRFileNodeServlet/etd_derivate_00000034/thomsena_ss18.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
