Formation of polyamines in the rumen of goats during growth
Acta Veterinaria Scandinavica 23(2): 275-294
Ornithine decarboxylase (E.C. 220.127.116.11), S-adenosylmethionine decarboxylase (E.C. 18.104.22.168) and their products putrescine, spermidine and spermine were estimated in the rumen liquid from 3 groups of growing kids and 23 adult goats. Polyamines were also estimated in the feedstuff used. Marked differences in polyamine synthesis in rumen liquid were observed between the different groups of kids. Two groups of kids growing up together with adult goats had at an age of 2-4 mo. a peak of a few days duration in enzyme activity, as well as in polyamine concentration. In these groups, ornithine decarboxylase activity reached maximal values of 158 .+-. 79 s (n = 4) and 100 (66-117) (n = 3) nmol[14CO2]/ml rumen liquid per h at an age of 120 and 77 days, respectively. The corresponding activity in rumen liquid from kids who were isolated from other animals was only .apprx. 1/10 of this value. By comparison, ornithine decarboxylase activity in adult goats was 30.7 .+-. 20 (n = 43) nmol[14CO2]/ml per h. In rumen liquid from kids grown up together with adults, concentrations of the polyamines reached maximum at about the same time as ornithine decarboxylase activity. The mean maximal concentration of putrescine in the 2 groups was .apprx. 350 and 500 nmol/ml, while the corresponding value for spermidine was .apprx. 200 nmol/ml in both groups. Relatively constant and high concentrations of polyamines were present in the feedstuff used. However, in growing kids the ruminal putrescine and spermidine concentration at time far exceeded those that could be accounted for by the estimated intake of polyamines by the food. Polyamines are probably formed in considerable amounts in rumen content of kids during the phase of rapid growth. Results from a few experiments with calves also indicate that this may be true for cattle.