Rumen escape and apparent degradation of amino acids after individual intraruminal administration to cows.
J Dairy Sci
; 80(12): 3325-32, 1997 Dec.
Article
em En
| MEDLINE
| ID: mdl-9436115
ABSTRACT
Apparent rumen degradation and escape of 18 amino acids (AA) after individual administration intraruminally were studied using two nonpregnant, nonlactating, rumen-cannulated cows fed a ration containing hay and concentrate twice daily. The pulse-dosages of AA were 75, 150, 300, and 600 mmol. Polyethylene glycol was used as the liquid marker. Rates of apparent degradation during the first 60 min (initial degradation) varied markedly among the AA; rates were highest for Ser, Asn, Glu, and Gln and lowest for Tyr, Val, Arg, and His. At the 75-mmol dosage, which corresponded to an initial substrate concentration of about 1 mM of rumen fluid, initial degradation varied between 95 and 40% of the dosage, depending on the AA. Rates, expressed as percentages of the dosage, decreased as dosages increased. During the first 8 h after administration, escape of the AA increased from a mean of 9% at the lowest dosage to a mean of 21% at the highest dosage. At the highest dosage, Met caused a net increase in the concentration of 11 of the other AA in rumen fluid. Twelve of the AA administered caused a net increase in the concentration of Ala in rumen fluid. Methionine and Lys are among the AA considered to be limiting to milk yield. These AA showed relatively high rumen escape values and may be useful as feed supplements even in an unprotected form.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Rúmen
/
Bovinos
/
Aminoácidos
Limite:
Animals
Idioma:
En
Revista:
J Dairy Sci
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Noruega