Untersuchungen zur Sezernierung endogener Aminosäuren in den Verdauungstrakt und zur Aminosäurenresorption beim Schwein

Abstract

A trial was performed with 2 fistula pigs (each with 2 fistulas, one located about 30 cm below the pyloric orifice and the other at the end of the small intestine). Animal A received a casein diet containing 14% crude protein for a period of 2 weeks before the tracer amino acid was administered. Animal B received the same diet for a period of 10 days and was then fed a diet (at the same protein level) containing gluten as sole protein source. The two tracer amino acids, 14C-U-L-leucine and 3H-4,5-(N)-L-lysine, were injected intravenously. The passage rates for dry matter, organic matter and N measured at the beginning of the small intestine were higher than the rate of intake. The rate of passage of amino acids was also found to be increased relative to the rate of intake. In general, this increase involved the non-essential amino acids to a much larger extent. A considerable proportion of the amino acids passing into the large intestine is not excreted with the faeces but is probably converted in catabolic processes. It is for this reason that any values for the efficiency of amino acid absorption calculated on the basis of data on the faecal excretion of amino acids will not provide conclusive evidence for the availability of dietary amino acids in processes of the intermediate metabolism. The rate of secretion of 3H and 14C radioactivity into the digesta of the small intestine was found to increase rapidly within 1-2 hrs after administration of the tracer amino acids. The 14C radioactivity detected was found to be almost exclusively derived from 14C leucine while only about 60% of the 3H activity found in the digesta of fistula I were shown to be bound to lysine. Labelled lysine and leucine (of endogenic origin) are absorbed into the small intestine at a slower rate (i.e. endogenic proteins are less efficiently digested) than the non-radioactive amino acids (of exogenic origin) so that a process of concentration of endogenic amino acids is observed towards the end of the small intestine.

Digestibility of amino acids in maize, wheat and barley meal, measured in pigs with ileo‐rectal anastomosis and isolation of the large intestine

“…It has been shown that amino acids in these secretions are poorly absorbed from the intestine. 25 The endogenous amino acid output measured in this trial was similar to that recorded by other workers.6Jc28 Endogenous nitrogenous losses have been shown to vary only very slightly with bodyweight changes. 16,29 Consequently, feeding PF1 and PF2 at different liveweights was not likely to have a large influence on endogenous output.…”

“…The DM, crude protein (Nx6. 25) and crude fibre contents of the test diets are shown in Table 2. The values of crude fibre concentration for the protein-free diets show that either there was incomplete recovery of the purified cellulose during analysis, or that impurities were present.…”

Porto-arterial plasma concentration differences of urea and ammonia-nitrogen in growing pigs given high-and low-fibre diets

“…This study (Sauer et al 1977) was done with diets ranging in crude fibre content from 39 to 108 g/kg. The predominance of non-essential amino acids contained in endogenous secretions recovered at the terminal ileum is also supported by the work of Zebrowska et al (1976). Even after ingestion of dietary protein, the abundance of non-essential amino acids in endogenous matter appearing at the terminal ileum seems to persist (Taverner et al 1981).…”

Digestion in the pig between 7 and 35 d of age 6. The digestion of hydrolyzed milk and soya-bean proteins

“…A greater apparent absorption of N from the hydrolyzed proteins than the intact proteins occurred in the duodenum and jejunum. There were no differences in the lower parts of the digestive tract suggesting that all readily-digestible protein had been digested and that the slower digestion of the less-digestible fractions including endogenous secretions (Zebrowska et al 1976) occurred in the ileum, caecum and large intestines.…”