| 摘要 |
(A) Domesticated ruminants are orally given aplasmomycin or a related cpd. of formula (I): (R1 and R2 are H or MeCO; either (a) the 3-, 3'- and 9'-C atoms are all in the R-configuration; X is CH2CH2 or trans-CH=CH; and Y is a gp. of formula (II): where X1 is bonded to the CH2 and the ring C is bonded to the O atom, X1 being CH2CH2 or trans-CH=CH; Z is Na, K, Li, Cs, NH4 or R3R4R5R6N circled positive; R3-R6 are H or 1-6C alkyl; (b) the 3-, 3'- and 9'-C atoms are all in the S-configuration; X is CH2CH2; and Y is a gp. of formula (III) or (IV): where the CH2 is bonded to the CH2 in (I) and the CH is bonded to the O atom, X2 being CH2CH2 or cis-CH=CH; or (c[ the 3-, 3'- and 9'-C atoms are all in the S-configuration; X is CH2CH2; and Y is a gp. of formula (V): (B) Streptomyces griseus NCIB 11371 is new. (C) (C) are new when (1) in gp. (a) one of X and X1 is CH2CH2 and the other is trans-CH=CH, or X and X1 are both CH2CH2; (2) in gp. (a) X is trans-CH=CH, X1 is trans-CH=CH and Z is K, Li, Cs, NH4 or R3R4R5R6N circled positive; (3) in gp. (b) Y is a (III) or (IV) gp. in which X2 is CH2CH2; (4) in gp. (C) X2 is CH2CH2, X is CH2CH2 and Z is K, Li, Cs, NH4 or R3R4R5R6N. (I) in ruminants modifies rumen metabolism so that the propn. of propionic acid formed at the expense of CH4 and/or acetic acid is increased, so that growth rate is enhanced, and food conversion efficiency is increased. (I) are administered at 0.01-30 mg./kg. in feeds, licks etc. for all, or a selected period, of the animals' growth cycle. (I) do not show toxic effects at effective levels. |
