An experiment was conducted to determine how feeding calcium (Ca)-deficient diet would affect gastrointestinal pH and volatile fatty acids (VFAs), Ca digestibility, bone mineral density (BMD), and performance in nursery pigs; and if supplementation of nondigestible oligosaccharides would affect these same parameters. In total, 240 weaned pigs (BW = 7.1 kg) were placed into 80 pens with 3 pigs/pen. The eight dietary treatments consisted of: 1) positive control (PC, 0.83% total Ca), 2) negative control (NC, 0.50% total Ca), 3 and 4) NC + 5% or 7.5% soluble corn fiber (SCF), 5 and 6) NC + 5% or 7.5% resistant corn starch (rCS), 7 and 8) NC + 0.25% or 0.50% fat-protected butyrate (pBRT). Pigs were ad libitum fed the dietary treatments for 21 d to determine average daily gain (ADG), average daily feed intake (ADFI) and gain:feed ratio (GF) with a fecal sample collected from each pen to determine Ca digestibility using acid insoluble ash as the dietary marker, with 1 pig/pen euthanized on d 21 for collection of ileal and colon contents and the left humerus. Pigs fed the NC diet had a lower colonic pH compared with pigs fed the PC (P = 0.06) but no effect on total VFA was observed (P > 0.10). Pigs fed diets containing SCF and rCS had lower colonic pH and total VFA compared to pigs fed the NC diet (P ≤ 0.05). Pigs fed diets containing pBRT had greater colonic total VFA compared to pigs fed the NC diet (P ≤ 0.07), but no difference in colonic pH was observed (P > 0.10). Pigs fed the NC diet had a greater Ca digestibility compared to pigs fed the PC (P ≤ 0.01), with no treatment to the NC having any effect on Ca digestibility compared to pigs fed the NC (P > 0.10). There was no effect of dietary Ca level on BMD and no overall addition of feeding SCF, rCS, or pBRT on BMD compared to pigs fed the NC (P > 0.10). There was no impact on pig ADG, ADFI, or GF by reducing dietary Ca by 40% (i.e., pigs fed the NC) compared to pigs fed the PC (P > 0.10). Relative to pigs fed the NC, there was no overall effect of SCF, rCS, or pBRT on ADG, ADFI, or GF (P > 0.10). In conclusion, feeding young pigs a Ca-deficient diet reduced colonic pH, increased digestibility of Ca, but had no impact on bone mineralization or overall pig performance. Supplementation of nondigestible oligosaccharides pr protected butyrate had either no effect or an inconsistent effect on colonic pH, Ca, or PHOS digestibility, bone mineralization, or overall pig performance.
Keywords: bone mineral content and density; calcium digestibility; protected butyrate; resistant corn starch; soluble corn fiber; volatile fatty acids.
Calcium (Ca) is a major component of the skeleton in addition to being essential for growth and is imperative for bone mass development. Improvement in Ca absorption in Ca-deficient diets has been shown in human and rodent studies when nondigestible oligosaccharides have been consumed due to a modification of gastrointestinal conditions which increase mineral solubility. Because swine have been shown to be an excellent model for human nutrition research, an experiment was conducted to determine how a moderately Ca-deficient diet would affect gastrointestinal fermentation conditions, Ca and phosphorus (PHOS) digestibility, bone mineralization, and growth performance in nursery pigs; and if supplementation of nondigestible oligosaccharides would affect these same parameters. Results indicate that feeding young pigs a diet below recommended levels of Ca reduced colonic pH, increased apparent total-tract digestibility of Ca and PHOS, but had no impact on bone mineralization or overall pig performance. Supplementation of nondigestible oligosaccharides had inconsistent effects on colonic pH, and did not affect Ca or PHOS digestibility, bone mineralization, or overall pig performance.
Published by Oxford University Press on behalf of the American Society of Animal Science 2023.