Use of polyethylene glycol (PEG) to assess the effect of condensed tannins on nitrogen balance and digestibility in sheep fed fresh sainfoin (Onobrychis viciifolia) - Archive ouverte HAL Accéder directement au contenu
Poster De Conférence Année : 2011

Use of polyethylene glycol (PEG) to assess the effect of condensed tannins on nitrogen balance and digestibility in sheep fed fresh sainfoin (Onobrychis viciifolia)

Résumé

The aim of this study was to investigate the effects of the structure, the content and the biological activity of condensed tannins (CT) present in sainfoin (Onobrychis viciifolia) on in vivo digestive characteristics in sheep. Sainfoin was studied as fresh forage at the first vegetation cycle at one phenological stage (end of flowering) and at the second vegetation cycle (start of flowering, 5 weeks after the end of flowering). The feeding trial involved 12 sheep; six received polyethylene glycol (PEG) to neutralise the effects of CT, and the other six were dosed with water. Organic matter (OM) digestibility, total tract N digestibility and nitrogen (N) balance were measured on the whole plant. Total tract N digestibility was increased by the addition of PEG (P<0.001) and by the vegetation cycle (P<0.001). PEG did not affect OM digestibility (P=0.156). Inactivation of tannins by PEG tended to increase N excretion in urine (P=0.0754), but this was offset by lower faecal N excretion (P<0.001). Body N retention was not affected by tannins. Kinetic studies of total nitrogen (tN) and ammonia nitrogen (NH3-N) in rumen fluid were made before and 1.5 h, 3 h, 6 h after feeding. Sainfoin CT decreased rumen fluid soluble N (P<0.05) and NH3-N (P<0.05). Biological activity of CT increased with the vegetation cycle (from 1.02±0.06 g tannic acid equivalent/100 g dry matter (DM) to 1.58±0.72 g tannic acid equivalent/100 g DM). CT content increased, according to thiolysis, with the vegetation cycle (from 6.2±0.2 g CT/kg DM to 13.6±1.6 g CT/kg DM). Prodelphinidin:procyanidin ratios (PD:PC) were similar for both vegetation cycles. The mDP of tannins of sainfoin was lower at the start of flowering (11) in relation with their higher biological activity and CT content.
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Dates et versions

hal-02745826 , version 1 (03-06-2020)

Identifiants

  • HAL Id : hal-02745826 , version 1
  • PRODINRA : 197695

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Aikaterini Theodoridou, Jocelyne J. Aufrere, Donato Andueza, René Baumont. Use of polyethylene glycol (PEG) to assess the effect of condensed tannins on nitrogen balance and digestibility in sheep fed fresh sainfoin (Onobrychis viciifolia). 3. Panhellenic Conference of Animal Production, Feb 2011, Thessaloniki, Greece. Alexander technological educational institute of Thessaloniki, 592 p., 2011, 3rd Pan-Hellenic congress in technology of animal production. ⟨hal-02745826⟩
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