The effect of condensed tannin containing diets on whole body
amino acid utilisation in Romney sheep: consequences for wool growth
J. Lee, P.M. Harris, B.R. Sinclair, B.P. Treloar
AgResearch, Fitzherbert Science Centre, Private Bag 11030,
Palmerston North, New Zealand
Proceedings of the New Zealand Society of Animal Production.
1992, 52: 243-246
Three groups of sheep housed in metabolism crates were fed
Lotus corniculatus (low tannin), L. pendunculatus (medium
tannin) and ryegrass pasture (control) respectively. After a period of
adaptation to each of the diets, labelled 35S-cysteine and „H-
phenylalanine were infused (separately) for 6 hours via a jugular
catheter. Blood samples were taken at 5 and 6 hours and irreversible
loss rates were determined from radioactivity and pool size measurements
for cysteine and phenylalanine for sheep on each diet. Blood
concentrations of cysteine, glutathione and phenylalanine, wool
production and dry matter intake were also determined. Significant
treatment differences were found for circulating cysteine, (36.2 ± 4,
36.3 ± 2.8, 60 ± 3.9 µN)m glutathione (1.76 ± 0.14, 1.08 ± 0.1, 1.63 ±
0.14 mM) and cysteine ILR (16.5 ± 3.2, 27.3 ± 2.2, 35.6 ± 3.1m moles d-
1) for the L. corniculatus pasture and L. pedunculatus
treatments respectively. Phenylalanine blood concentrations and
phenylalanine ILR were not significantly different among treatments.
Although L. peduculatus, which contains most tannin,
significantly improved cysteine supply and utilization at whole body
level, this was not reflected in gains in wool production.
Keywords: NZSAPAB;
Condensed tannin; cysteine; glutathione; phenylalanine;
irreversible loss rate; wool; sheep.
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Last Updated 25-01-1997
