Determination of bacterial amino acid contribution to ileal digesta from pigs using ³⁵S and DAPA marker techniques

Abstract

A study was conducted using two duodenal and ileal cannulated, 45 kg gilts, to determine the bacterial amino acid contribution to amino acids in ileal digesta by using 35 S and diaminopimelic acid (DAPA) as bacterial protein markers. Both the 35 S and DAPA marker techniques are based on the assumption that a representative purified bacterial pellet is collected from ileal digesta samples. The 35 S technique was modified from previous methods by isolating a specific methionine sulphone marker fraction. However, results from the 35 S-methionine sulphone marker technique exceeded sensible physiological estimates (mean of 190.6%) of the bacterial amino acid contribution to ileal digesta amino acids. Whereas, the mean bacterial amino acid contribution to ileal digesta was 29.4% when determined using the DAPA marker technique. The values determined by DAPA are within the 20 to 34% range of values that have been reported for pigs fed cereal based diets. The amino acid composition was different (P^0.05) between bacteria and undigested non-bacterial residues for isoleucine, aspartic acid, glycine, cysteine and tyrosine. The high concentration of glycine in non-bacterial residues relative to other amino acids measured and the corresponding low concentration in bacterial samples suggests that the bacterial pellet fraction was free of contamination. It was therefore concluded, that further research into determining the bacterial contribution to amino acids in ileal digesta is warranted.

Effects of dietary Ca/P ratio, P level and microbial phytase supplementation on nutrient digestibilities in growing pigs: breakdown of phytic acid, partition of P and phytase activity along the intestinal tract

“…The percentages of IP6 to total P in vegetable feedstuffs used in our study were well within the range of 50-85%, as reported by LANTZSCH (1990), EECKHOUT and DE PAEPE (1994) and POINTILLART (1994). This means that the relative contribution of Po to the issue of P digestibility of vegetable feedstuffs, can be quite considerable.…”

“…Partition of N in the ileal digesta of pigs in UD-N, WS-N and BED-N, similar to the present results, has been reported by other researchers: 10-16%, 62-67% and 17-27%, respectively (DIERICK et al 1983) and 17-23%, 43-62% and 22-40%, respectively (DIERICK et al 1990). Also studies of POPPE et al (1983), DROCHNER (1984), DUGAN et al (1994), BARTELT et al (1997) andCAINE et al (1997) show that 20 to 30% of N in ileal digesta originates from bacterial N. Therefore, bacterial fermentation processes in the terminal ileum should not be underestimated. Dense populations of culturable anaerobic bacteria (8.3×10 9 to 8.8×10 9 per g of digesta) were found by JENSEN and JÖ RGENSEN (1994) in the last third of the small intestine, indicating that substantial microbial activity takes place in that portion of the gut in pigs.…”

“…Plant ingredients used to formulate diets for pigs and poultry contain within them sufficient amounts of phosphorus (P) to meet the P requirements of pigs and poultry. However, approximately two-thirds of intrinsic phosphorus in vegetable feedstuffs is in the form of poorly soluble salts of phytic acid (IP6, myo-inositol hexakisphosphate) and, to a small extent, other inositol phosphates (DE BOEVER et al 1994;EECKHOUT and DE PAEPE 1994). The digestibility of these salts for monogastrics is very limited and thus they will predominantly be excreted.…”

Ileal digestibilities of neutral detergent fiber, crude protein, and amino acids associated with neutral detergent fiber in wheat shorts for growing pigs.

“…However, the apparent ileal CP digestibilities of the diets fed in the study by Schulze et al (1994) ranged from 84.0 to 88.9%, which are higher than values reported in the studies by Huang et al (1999). The bacterial nitrogen content in ileal digesta of pigs was also determined by Wuensche et al (1991), Dugan et al (1994), and Caine et al (1999). In some of the studies, quantitative contributions (g/d) were not reported.…”

“…Bacteria were isolated from the pooled digesta and fecal samples as described by Dugan et al (1994). Bacterial nitrogen was quantified using diaminopimelic acid (DAPA) as an indicator and calculated on the basis of 26.4 mg DAPA/g bacterial nitrogen according to Wuensche et al (1991).…”