Determination of endogenous nitrogen associated with bacteria in ileal digesta of pigs receiving cereal-based diets with or without fish meal and various fibre supplements by using a simple ¹⁵N-dilution technique

Abstract

Four Gottinger miniature pigs and five domestic pigs (Landrace) of similar body weight fitted with an ileocaecal re-entrant cannula were given each a cereal-based diets with or without fish meal (Treatments 1 and 2). The diets contained increasing levels of partially hydrolysed straw meal and pectin (2:1 w/w). On day 3, 5 and 7 after the last administration of 15 NH 4 C1 given with the diets during five days the ileal flow of endogenous nitrogen (N) was measured using the atom % 15 N excess in urinary N as indicator for that in endogenous N. The 15 N-enrichments in urinary N, in trichloroacetic acid (TCA)-soluble N of blood plasma as well as in TCA-soluble and -preciptable N in the pancreas and small intestine were nearly the same. Furthermore, the contribution of endogenous N to total, TCA-preciptable and bacterial N of ileal digesta was not affected by the three collection periods. Urinary N seems to be the easiest accessible and valid indicator for determination of the endogenous N under these experimental conditions. Neither the fibre supplements nor the

Effects of a dietary organic acid mixture and of dietary fibre levels on ileal and faecal nutrient apparent digestibility, bacterial nitrogen flow, microbial metabolite concentrations and rate of passage in the digestive tract of pigs

“…In this study, bacterial N contributed 0.42 to 0.46 and 0.42 to 0.55 of N in the ileum, as assessed by purine and DAPA flows, respectively. These proportions are within the wide range of values reported in the literature using both bacterial markers (Wü nsche et al, 1991;Schulze et al, 1994;Bartelt et al, 1999;Huang et al, 2001;Partanen et al, 2001).…”

“…In the studies of Schulze et al (1994) and Bartelt et al (1999), increasing fibre inclusions did not affect bacterial N flow as assessed by DAPA flow. In this study, however, increasing levels of dietary fibre increased the flow of DAPA and consequently of bacterial N flow as assessed by DAPA flow.…”

“…The DAPA / bacterial N ratios of 34 and 40 mg/g are among the highest reported in the literature. Bartelt et al (1999) obtained DAPA / bacterial N ratios of 34.4 and 22.3 mg/g for miniature and domestic pigs with re-entrant ileo-caecal cannulae. Kö hler et al (1992) reported somewhat lower values for pigs with PVTC cannulae (13.9 to 16.7 mg/g) and ileo-rectal anastomosis (14.3 to 27.5 mg/g).…”

“…Dietary formic acid has been shown not to influence the secretion of pancreatic juice (Lesniewska et al, 2001), whereas dietary soluble fibres have been shown to increase the secretion of saliva, gastric and pancreatic juices, and bile considerably (Mosenthin et al, 1994). Endogenous secretions provide an easily available N source for bacteria (Bartelt et al, 1999). In addition, the carbohydrate composition of a diet has a distinct influence on the microbial fermentation and the de novo synthesis of bacterial amino acids in the small intestine (Wenk, 2001).…”

“…The estimated amounts of bacterial nitrogen (N) in ileal digesta have ranged greatly from 0.14 up to 0.74 of total ileal N (Wü nsche et al, 1991;Schulze et al, 1994;Bartelt et al, 1999;Huang et al, 2001). Because organic acids are antimicrobial agents, their effects on ileal apparent amino acid digestibilities can be mediated via microbes of the digestive tract.…”