The development of the digestive system of the young animal. VI. The metabolism of short-chain fatty acids by the rumen and caecal wall of the young lamb

Abstract

1. Rumen and caecal wall tissues were taken at slaughter from lambs varying in age from newborn to 11 weeks. The ability of these tissues to metabolize the short-chain fatty acids, acetic, propionic and butyric acid was compared with tissues from adult sheep. Ketone body production was measured.2. The utilization of butyrate by the rumen wall in the newborn lamb was lower than in the adult, but exceeded the adult levels at 3 weeks of age and maintained this higher utilization to 11 weeks and probably longer. Ketone body production was negligible at birth but followed butyrate utilization closely thereafter.3. The caecal wall in the newborn lamb utilized butyrate at a much higher rate than the adult sheep tissue. Foetal lamb caecal tissue utilized butyrate to the same extent as in the newborn lamb. Levels were, however, typical of the adult within a day or two of birth and showed no subsequent effect of age. Ketone body production was negligible at all ages.4. Rumen development in milk-fed lambs slaughtered at 7 and 9 weeks of age was retarded anatomically and showed decreased capacity in the utilization of butyrate.5. The utilization of acetate and propionate by rumen and caecal tissues showed no marked change due to age. Ketone body production from these acids was low.

Body composition of animals during sucking and the immediate post-weaning period

“…In the pig, for example, while those enzymes concerned with the digestion of maltose, sucrose and starch increase in activity from soon after birth, the ability to digest cellulose in the foregut never develops. On the other hand, in 'foregut fermented such as ruminants, and probably also in many marsupials (Hume, 1982), while the enzymes necessary for the digestion of the nutrients in milk are present at birth, the enzymes required for the digestion of maltose and starch are virtually absent, and for sucrose totally absent, so that the utilization of these carbohydrates, and of cellulose, must await the establishment of a microbial population and, in the case of the ruminants, the maturing of the rumen mucosa (Walker & Walker, 1961;Walker & Simmonds, 1962).…”

Transport and metabolism of butyrate by isolated rumen epithelium

“…was taken from the upper area of the same sac. The activity of the system converting butyrate into ketone bodies (on a dry-weight basis) is known to increase with papillae size as the sheep grows (Walker & Simmonds, 1962;Hird & Weidemann, 1964).…”

Ketone-body synthesis in relation to age of lambs

“…It was found possible to strip the epithellum from the attached layers of muscle of the rumen tissue from animals of all ages. In certain comparative experiments, tissue with muscle layers attached was prepared by the method described by Walker & Simmonds (1962). Samples of liverwere hand-sliced according to the method described by Deutsch (1936).…”