Effect of dietary neutral detergent fiber on ileal digestibility and portal flux of nitrogen and amino acids and on nitrogen utilization in growing pigs.

Abstract

Two experiments were conducted to determine the effects of dietary NDF on apparent ileal and fecal digestibility and portal flux of nitrogen (N) and amino acids, and on N retention in growing pigs. In four equal portions (at 0600, 1200, 1800, and 2400) barrows on Treatment B received a basal diet, based on casein, cornstarch, and dextrose, at a feeding level of 2.6 times energy for maintenance. Barrows on Treatment B+NDF received an additional amount of 15% (wt/wt) of purified wheat bran NDF (pNDF). In Exp. 1, four ileally cannulated barrows (40 to 75 kg) were used in a crossover arrangement comprising two treatments and three periods. The addition of pNDF decreased ileal N digestibility from 94.1 to 88.9% (P < .001), whereas ileal digestibility of most amino acids was 2 to 5.5 percentage units lower (P < .001). Utilization of ileally digested N increased from 64 to 72% with the addition of pNDF, presumably because of the contribution of pNDF to the energy supply. In Exp. 2, three barrows (30 to 54 kg) fitted with catheters in the portal vein and the mesenteric vein and artery were used in a crossover arrangement comprising two treatments and five periods. Portal absorption of nutrients was derived by multiplying the porto-arterial plasma concentration differences by portal vein plasma flow. The pNDF did not significantly affect the absorption of ileally digested amino acids and the portal flux of ammonia and urea. The results showed that addition of NDF reduced amino acid digestibility, but not the portal flux of digested amino acids, and NDF energy presumably improved utilization of ileally digested amino acids.

Meta-analysis of the amino acid digestibility of oilseed meal in growing pigs

“…Among the chemical components, NDF provided the best estimate thanks to a highly predictable negative linear relationship (Table 2). These results are in agreement with the existing literature (Lenis et al, 1996;Dilger et al, 2004). Dilger et al (2004) also found various linear reductions of the EAA SID of SBM with progressive inclusion of soy hulls.…”

Fibre components negatively affect ileal protein digestibility in pigs

“…In studies on pigs fed purified diets containing NDF from wheat, ileal protein digestibility decreased by 4.9 percentage units when 18% NDF was included (Schulze et al, 1994). A similar effect was observed by Lenis et al (1996) in pigs fed a diet containing 15% NDF. In a recently published paper, Fan et al (2001) evaluated the effect of NDF content on apparent ileal amino acid digestibility in six high-protein wheat samples given to growing-finishing pigs.…”

Variability of apparent ileal amino acid digestibility in different pea samples for growing-finishing pigs

“…It has been well established that dietary NDF has direct adverse effects on apparent ileal CP and AA digestibility in pigs. It was shown that the dietary inclusion of water-insoluble fiber depressed the apparent ileal digestibility values of CP and AA (Graham et al 1986;Li et al 1994;Schulze et al 1994;Lenis et al 1996). The lower ileal digestibility values of CP and AA with increasing water-insoluble fiber content may be attributed to an increase in the rate of passage of digesta (Stanogias and Pearce 1985) and increased distal ileal losses of endogenous CP and AA (Sauer et al 1977;Taverner et al 1981;De Lange et al 1989;Furuya and Kaji 1992;Leterme et al 1992).…”