Efficiency of utilizing ileal digestible lysine and threonine for whole body protein deposition in growing pigs is reduced when dietary casein is replaced by wheat shorts1,2

Abstract

To determine the effect of dietary inclusion level of wheat shorts (WS; a high nonstarch poly-saccharide-containing feed ingredient) and casein (CS; a control) on the efficiency of utilizing ileal digestible Lys (kLys) and Thr (kThr) for whole body protein deposition (PD) in the growing pig, 2 separate N-balance studies were conducted with either Lys or Thr as first-limiting AA in cornstarch-based diets. For the Lys study, a basal diet (L-basal) was formulated to contain 0.24 g of standardized ileal digestible (SID) Lys per MJ of DE, to which 0.095 or 0.19 g of SID Lys per MJ of DE were added using either CS (L-CS2 or L-CS3, respectively) or WS (L-WS2 or L-WS3, respectively). A sixth diet was evaluated that was similar to L-CS3 but to which 6% pectin (L-pectin) was added as a source of soluble nonstarch polysaccharides. For the Thr study, the basal diet (T-basal) was formulated to contain 0.14 g of SID Thr per MJ of DE, to which 0.055 or 0.11 g of SID Thr per MJ of DE were added from CS (T-CS2 or T-CS3, respectively) or from WS (T-WS2 and T-WS3, respectively). A sixth diet was evaluated that was similar to T-CS3 but to which 6% pectin was added (T-pectin). Increasing SID Lys intake from CS did not influence kLys for PD (P > 0.10), whereas increasing SID Lys intake from WS reduced kLys for PD (P = 0.001; 89 vs. 79%). Inclusion of 6% pectin had no effect on kLys for PD (P > 0.10). Increasing SID Thr intake from CS also did not influence kThr for PD (P > 0.10), whereas kThr for PD was reduced at the greatest dietary inclusion level of WS (P < 0.001; 90 vs. 77%). Pectin inclusion had no effect on kThr for PD (P > 0.10). The inefficiency of utilizing ileal digestible Lys intake for PD may be attributed to nonreactive Lys in WS. The negative impact of including high levels of WS in the diet of pigs on kThr seems to be associated with fiber content of WS; it was not related to increased endogenous ileal AA losses at the distal ileum. The impact of dietary AA source on the use of ileal digestible Lys and Thr for PD, or other body functions, is substantial and should be considered in the formulation of pig diets. Further research is warranted to elucidate the mechanisms contributing to substantial dietary effects on Thr use for PD.

Maintenance requirement and deposition efficiency of lysine in pigs

“…This means that 10% of the absorbed lysine was lost during metabolic processes. A high efficiency of lysine utilization was also found by other authors: 89% by Libao-Mercado et al (2006) and 91% by Heger et al (2008b).…”

“…The values of lysine deposition efficiency found by Libao-Mercado et al (2006) and Heger et al (2008) show significant variations, possibly due to the methodological differences between the experiments and the premises assumed in the calculations.…”

“…The deposition efficiency of lysine was determined by the angular coefficient of the line originated by the regression of amino acid retention and intake (Libao-Mercado et al, 2006). The coefficient is the slope of the amino acid deposition efficiency, which is the proportion of ingested amino acid that was deposited in the animal body (Sakomura & Rostagno, 2007).…”

Bioavailability of threonine and tryptophan in peanut meal for starter pigs using slope-ratio assay

“…In a recent study using pigs raised from 10 to 25 kg body weight, Wang et al (2006) reported increases in weight gain and feed efficiency with increasing dietary thr. The increase in weight gain and feed efficiency of pigs in response to dietary thr in the present study is expected to include improved protein deposition as observed in studies reported by Zhu et al (2005) and Libao-Mercado et al (2006). Furthermore, Adeola et al (1994) observed linear increases in weights of Table 6 Estimates of relative bioavailability (RB) of tryptophan in peanut meal from daily weight gain (g/day) and gain : feed ratio (g/kg) as response criteria using supplemental dietary tryptophan concentration (g/kg), daily total tryptophan intake (g/day), or daily supplemental tryptophan intake (g/day) as independent variables ham and loin muscles in 10 kg pigs fed graded dietary levels of thr.…”

An integrated approach to the safety assessment of food additives in early life

“…As discussed for other fibers in this document, increases in viscosity and concomitant decreases in digestibility have been observed with high levels of pectin and other dietary fibers, and are linked with decrease feed intake. [165][166][167][168][169][170][171][172][173][174][175][176][177][178][179][180][181][182][183] Thus, the impact of high levels of pectin on growth in the piglet trials is due to delayed gastric emptying and/or prolonged gut transit resulting from the viscosity of the material rather than a toxicological effect. In studies in older growing pigs (greater than 6 weeks old and older), growth effects were not observed at pectin exposures up to 6000 mg/kg bw per day, well above the exposures that impacted growth in the neonatal piglets.…”