38 research outputs found

    Elevated CO\u3csub\u3e2\u3c/sub\u3e and Extreme Climatic Events Modify Nitrogen Content and Ruminal Protein Digestion of Temperate Grassland

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    This study was aimed at analyzing changes in nitrogen (N) content and in vitro protein rumen digestion of an upland grassland exposed to climate changes in controlled conditions. Monoliths of grassland were inserted in 12 macrocosms in which climatic conditions for the 2050s were simulated (i.e., +2.3°C and 33 mm less precipitation compared to the current climatic conditions). Six of them were subjected to ambient CO2 (390 ppm) while the other six were subjected to elevated CO2 (520 ppm). After four months, an extreme climatic event (ECE) consisting of four weeks of reducted precipitation (-50%) followed by two weeks without irrigation combined with a heat wave (+6°C) were applied in three macrocosms at ambient CO2 and three macrocosms at elevated CO2. Then, all the macrocosms were irrigated to allow the vegetation to recover. The N content and in vitro parameters of rumen protein digestion were measured on plant samples collected before the extreme event (two cuts) and after recovery. Our results indicate that, irrespective of the sampling date, elevated CO2 results in a decrease in plant N content (P \u3c 0.01). Inversely, the application of the extreme event resulted in a large increase in N content (P \u3c 0.001) without a significant interaction with the CO2 effect. These changes significantly impacted ruminal protein digestion as evidenced by changes in the production of the fermentation end-products indicators of the proteolysis, namely ammonia and iso-volatile fatty acids. We conclude that several components of climate change can impact the nitrogenous quality of the forage and its use by ruminants

    Understanding the Effects of a Tannin Extract on Forage Protein Digestion in the Rumen and Abomasum Using a Dynamic Artificial Digestive System Coupled to a Digestomic Approach

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    Improving the use efficiency of dietary protein in ruminants is a major challenge to decrease feed supplementation and significantly decrease nitrogen (N) losses to the environment. The aim of this study was to characterize the effects of tannins on protein digestion in the rumen and in conditions simulating the abomasum, using a dynamic in vitro digestive system coupled to a digestomic approach. Three ruminally-cannulated sheep fed with alfalfa hay were infused daily with a solution of tannins, while three other sheep were infused with water (control). Standardized ruminal fluid was introduced into the digester, which simulated the transit of digesta under physicochemical conditions mimicking the abomasum in terms of pH regulation, digestive enzyme infusions and transit rate. Protein degradation in the rumen and in the simulated abomasum was analyzed by determination of fermentation end-products, and identification and quantification of peptides (Label Free Quantification) by LC-MS/MS high resolution (Orbitrap). The analysis of rumen samples showed that tannins result in a clear decrease of fermentation end-products related to protein degradation, namely ammonia (NH3) and iso-volatile fatty acids (VFA), and a greater abundance of the Rubisco, a major plant protein. In the simulated abomasal compartment, the peptidomic analysis showed that the hydrolysis intensity of Rubisco was higher in the presence of tannins compared to the control group. These results indicate that protein-tannin complexes could be dissociated in the physico-chemical conditions of the abomasum, increasing the flow of peptides to the intestine after protection of protein by tannins in the rumen

    Patterns of in vitro rumen fermentation of silage mixtures including sainfoin and red clover as bioactive legumes

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    International audienceIn this study, we tested the effects of the inclusion in silages of bioactive legumes containing condensed tannins (CF) or polyphenol oxidase (PPO), ensiled alone or in mixture with one grass species, on in vitro rumen fermentations. Six mini-silos were prepared in triplicate as follows: pure sainfoin (SF), pure red clover (RC), pure timothy (T, control without bioactive compounds); binary mixtures T-SF and T-RC (in g/kg on a DM basis, 500:500); ternary mixture T-SF-RC (in g/kg on a DM basis, 500:250:250). Samples from each mini-silo were incubated under anaerobic conditions in culture bottles containing buffered rumen fluid from sheep. Rumen fermentation parameters, namely DM disappearance, volatile fatty acids (VFA), ammonia (NH3), gas production and methane (CH4) were determined. The presence of RC in mixtures with T or T-SF results in fermentation similar to pure T and a positive associative effect between T and RC on total VFA production was observed (P = 0.029). The NH3: total N ratio was similar among the treatments, but lower values for NH3: insoluble N ratio in silages containing SF or RC (P<0.05, except for T-SF) indicates that the bioactive compounds can limit silage protein degradation in the rumen. The CH4 production per g of DM only tended to differ among treatments (P=0.096), being slightly lower for pure SF than for pure T and RC, probably due to differences in the fermentation pathways towards less acetate and butyrate productions. Overall, the benefits of including RC in forage mixtures previously observed on silage quality are also present on ruminal digestion efficiency

    Feeding lambs with silage mixtures of grass, sainfoin and red clover improves meat oxidative stability under high oxidative challenge

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    PubMedID: 31129486This study investigated the oxidative stability of meat from lambs fed silages in which timothy grass was totally or partially replaced by sainfoin and/or red clover. Five groups of 8 lambs were fed the following silages: timothy grass (T), mixture (50:50) of timothy with either sainfoin (T-SF) or red clover (T-RC), mixture of timothy, sainfoin and red clover (50:25:25; T-SF-RC), or mixture (50:50) of sainfoin and red clover (SF-RC). Feeding the silages containing red clover (T-RC, T-SF-RC and SF-RC) decreased the deposition of vitamin E in muscle relative to the highly unsaturated fatty acids (P < .001), did not affect the oxidative stability of fresh meat, but reduced oxidative deterioration in cooked meat and in meat homogenates incubated with pro-oxidant catalysts (P < .001). The results of this study demonstrated that feeding lambs with silages containing sainfoin and red clover improve the oxidative stability of meat subjected to strong pro-oxidant conditions and suggest that these effects should be further clarified. © 2019 Elsevier LtdEuropean Commission: PITN-GA-2011-289377This investigation was supported by the European Commission through a Marie Curie Initial Training Network (PITN-GA-2011-289377, “LegumePlus” project)

    In vitro rumen simulated (RUSITEC) metabolism of freshly cut or wilted grasses with contrasting polyphenol oxidase activities

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    The study investigated in vitro simulated rumen metabolism of freshly cut and wilted cocksfoot [Dactylis glomerata; high polyphenol oxidase (PPO)] and tall fescue (Festuca arundinacea; low PPO). A 16‐vessel RUSITEC was used with the four treatment combinations: cocksfoot wilted (Cw); cocksfoot fresh (Cf); tall fescue wilted (TFw) and tall fescue fresh (TFf). Rumen liquor was collected from four fistulated dairy cows maintained on permanent pasture. The experiment ran for 12 d with sampling of effluent for rumen parameters [volatile fatty acids (VFA) and NH3‐N] on days 10 and 11 at 0, 1, 2, 3, 4, 6, 8 and 24 h intervals. On days 9–12, gas production and composition were measured using a plastic gas collection bag attached to the effluent bottle. At the end of day 12, the grass residue and effluent from the vessels were collected and analysed for digestibility and lipid fractionation. Lipolysis was calculated as the proportional loss of glycerol‐based membrane lipid between the forage and residue. Polyphenol oxidase was higher (P < 0·001) in Cf than the other treatments; Cw was higher than both TF treatments, with no difference between TFw and TFf. The level of protein‐bound phenol (product of oxidation reaction) tended to be higher for Cw and TFw than Cf and TFf, (P < 0·1) and was higher for cocksfoot than tall fescue (P < 0·001). As an average across the day, NH3‐N was lower (P < 0·001) in cocksfoot than tall fescue, despite the lower nitrogen concentration of tall fescue, and in fresh as opposed to wilted grass (P < 0·001). There was a trend (P < 0·1) for lipolysis to be lower in cocksfoot than tall fescue, and for both wilted treatments to be lower than the fresh (P < 0·05). Total VFA concentration was not different across treatments, although there were differences in molar proportions of individual VFA. Cocksfoot as opposed to tall fescue showed a small effect in lowering lipolytic and proteolytic activity (release of NH3‐N), although other differences between the grasses other than just PPO activity such as lipase activity, diphenol substrate content and digestibility may have greater effects between the grasses confounding the effect of PPO
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