A 2 × 2 factorial experiment was car- ried out to evaluate the effect of herbage or concen- trate feeding and dietary tannin supplementation on fatty acid metabolism and composition in sheep rumi- nal fluid, plasma, and intramuscular fat. Twenty-eight male lambs were divided into 2 equal groups at 45 d of age and kept in individual pens. One group was given exclusively fresh herbage (vetch), and the other group was fed a concentrate-based diet. Within each treat- ment, one-half of the lambs received supplementation of quebracho powder, providing 4.0% of dietary DM as tannins. Before slaughter, blood samples were collected. The animals were slaughtered at 105 d of age, and ru- minal contents and LM were collected. Blood plasma, ruminal fluid, and LM fatty acid composition was de- termined by gas chromatography. Tannin supplementa- tion reduced (P < 0.05) the concentration of stearic acid (−49%) and increased the concentration of vacce- nic acid (+97%) in ruminal fluid from concentrate-fed lambs. Within concentrate- and herbage-based diets, tannin supplementation reduced the accumulation of SFA in blood (P < 0.05) compared with lambs fed the tannin-free diets. When tannins were included in the concentrate, the LM contained 2-fold greater concen- trations of rumenic acid compared with the LM of the lambs fed the tannin-free concentrate (0.96 vs. 0.46% of total extracted fatty acids, respectively; P < 0.05). The concentration of PUFA was greater (P < 0.05) and SFA (P < 0.01) less in the LM from lambs fed the tannin-containing diets as compared with the animals receiving the tannin-free diets. These results confirm, in vivo, that tannins reduce ruminal biohydrogenation, as previously reported in vitro. This implies that tan- nin supplementation could be a useful strategy to in- crease the rumenic acid and PUFA content and to re- duce the SFA in ruminant meats. However, the correct dietary concentration of tannins should be carefully chosen to avoid negative effects on DMI and animal performance.

Metabolic fate of fatty acids involved in ruminal biohydrogenation in sheep fed concentrate or herbage with or without tannins

MELE, MARCELLO;SERRA, ANDREA;
2009-01-01

Abstract

A 2 × 2 factorial experiment was car- ried out to evaluate the effect of herbage or concen- trate feeding and dietary tannin supplementation on fatty acid metabolism and composition in sheep rumi- nal fluid, plasma, and intramuscular fat. Twenty-eight male lambs were divided into 2 equal groups at 45 d of age and kept in individual pens. One group was given exclusively fresh herbage (vetch), and the other group was fed a concentrate-based diet. Within each treat- ment, one-half of the lambs received supplementation of quebracho powder, providing 4.0% of dietary DM as tannins. Before slaughter, blood samples were collected. The animals were slaughtered at 105 d of age, and ru- minal contents and LM were collected. Blood plasma, ruminal fluid, and LM fatty acid composition was de- termined by gas chromatography. Tannin supplementa- tion reduced (P < 0.05) the concentration of stearic acid (−49%) and increased the concentration of vacce- nic acid (+97%) in ruminal fluid from concentrate-fed lambs. Within concentrate- and herbage-based diets, tannin supplementation reduced the accumulation of SFA in blood (P < 0.05) compared with lambs fed the tannin-free diets. When tannins were included in the concentrate, the LM contained 2-fold greater concen- trations of rumenic acid compared with the LM of the lambs fed the tannin-free concentrate (0.96 vs. 0.46% of total extracted fatty acids, respectively; P < 0.05). The concentration of PUFA was greater (P < 0.05) and SFA (P < 0.01) less in the LM from lambs fed the tannin-containing diets as compared with the animals receiving the tannin-free diets. These results confirm, in vivo, that tannins reduce ruminal biohydrogenation, as previously reported in vitro. This implies that tan- nin supplementation could be a useful strategy to in- crease the rumenic acid and PUFA content and to re- duce the SFA in ruminant meats. However, the correct dietary concentration of tannins should be carefully chosen to avoid negative effects on DMI and animal performance.
2009
Vasta, V; Mele, Marcello; Serra, Andrea; Scerra, M; Luciano, G; Lanza, M; Priolo, A.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/133658
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