Postprandial indole and skatole formation in the rumen when
feeding white clover, perennial ryegrass and Lotus corniculatus
N.M.SCHREURS, M.H. TAVENDALE, G.A. LANE, T.N. BARRY, D.M.
MAROTTI AND W.C. McNABB
AgResearch Limited, Grasslands Research Centre, Private Bag
11008, Palmerston North, New Zealand.
E-Mail:
NZSAP 2003 Abstract No. 5
Proceedings of the New Zealand Society of Animal Production
63: 14-17
In some international markets, meat and milk products from
pasture-fed animals is associated with an undesirable pastoral flavour
and odour. Sensory evaluation and chemical analysis of products has
associated these flavours and odours with the presence of skatole and
indole. Skatole and indole are formed in the rumen from the degradation
of dietary protein. Condensed tannins (CT) have been shown to reduce
protein degradation in the rumen and could reduce the formation of
skatole and indole. This study investigated the concentrations of
skatole and indole in the rumen of sheep after feeding white clover
(WC), perennial ryegrass (PRG) and the CT forage, Lotus corniculatus
(LC). Six rumen-fistulated Romney wethers were fed the cut forages and
rumen contents sampled at intervals after the start of feeding. Feeding
WC resulted in higher (P<0.05) peak concentrations of indole and
skatole in the rumen per kilogram of crude protein eaten (CPI) compared
to PRG and LC. There was a higher peak concentration of indole, but not
skatole, in the rumen of sheep fed PRG compared to sheep fed LC
(P<0.05). Feeding LC resulted in lower peak concentrations of skatole
compared to feeding WC and lower peak concentrations of indole than when
feeding WC or PRG. White clover in pastures may be a key factor of the
high skatole and indole contents in meat and milk products obtained from
pasture-based grazing systems. CT forages seem a likely solution to
reducing ruminal skatole and indole formation.
Keywords: NZSAPAB;
skatole; indole; meat flavour; condensed tannins; rumen; forages
Last Updated 8/07/2004
