| | In vitro analyses will be beneficial to characterize the existing variation in energy digestibility within specific feed ingredients such as grains and to develop procedures predicting nutritional value of grains for swine. Analytical procedures have been developed to determine in vitro energy digestibility and DE content for barley, but have not been validated for their suitability to predict in vivo values. First, 21 barley samples with a range in fiber content (5.7 to 12.1% ADF) and total-tract energy digestibility (51.9 to 78.5%) and DE content in grower pigs were subjected to an existing in vitro analysis in duplicate (Huang et al. 2003). Briefly, the procedure involved subsequent digestions with pepsin (6 hr), pancreatin (18 hr), and cellulase (24 hr), and DM and GE analyses of the barley sample and residue. The in vitro energy digestibility ranged from 63.7 to 82.2% for the 21 barley samples and relative errors for samples ranged from 0.2 to 4.8%. In vitro energy digestibility was strongly related to swine in vivo energy digestibility content (R2=0.81). Second, a subset of seven barley samples was subjected to quadruplicate in vitro analyses. In vitro energy digestibility ranged from 63.5 to 82.8% for the seven samples and the relative error was 4.2% for the barley sample with a low energy digestibility (63.5%) and ranged from 0.6 to 1.4% for the other six barley samples. For the seven barley samples, in vitro energy digestibility was strongly related to in vivo energy digestibility content (R2=0.97). In summary, with quadruplicate analyses, in vitro energy digestibility was an accurate predictor of in vivo energy digestibility. In vitro energy digestibility can be successful as the core analytical procedure to calibrate rapid analytical equipment to predict energy digestibility and therefore DE content of barley for grower pigs.
Key Words: swine, grain, analysis
R.T. Zijlstra* (1), W.C. Sauer (1), J.H. Helm (2), D.N. Overend (3), and R.W. Newkirk (4)
(1) University of Alberta, Edmonton, AB,
(2) Field Crop Development Centre, Lacombe, AB,
(3) Ridley Inc, Mankato, MN,
(4) Canadian International Grains Institute, Winnipeg, MB. |
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