T/YLSL 2-2019 Determination of rumen degradable starch (RDS) in total mixed ration of ruminant using nylon bag method

Scope

Scope: This standard specifies the terms and definitions, principles, reagents or materials, instruments and equipment, test conditions, sampling and sample preparation, analysis steps, test data processing, precision, and requirements for test reports for the determination of ruminal degradable starch in ruminant total mixed rations. This standard applies to the determination of ruminal degradable starch in ruminant total mixed rations using the nylon bag method. This standard does not apply to ruminant total mixed rations containing starch components that are optically active during analysis and insoluble in 40% ethanol. This standard does not apply to ruminant total mixed rations with a straight starch content exceeding 40% of the total starch. Main technical content: The test steps include sample collection and sample preparation. The relevant formulas for the measurement indicators in this standard are as follows: - Formula for calculating starch content W: See (1). W = (20000 × ((2.5α_1) / m_1 - (5α_2) / m_2)) / α_D20 where: W is the starch content in the sample, expressed in grams per kilogram (g/kg). α1 is the total optical rotation value measured. α2 is the optical rotation value of the ethanol-soluble fraction measured. m1 is the mass of the sample when measuring the total optical rotation. m2 is the mass of the sample when measuring the optical rotation of the ethanol-soluble fraction. αD20 is the specific rotation of pure starch measured at a wavelength of 589.3 nm (sodium spectral D line). - Formula for calculating the degradation rate dp of starch at different times: See (2). dp = (W_t - W_r) / W_t × 100% where: dp is the degradation rate of ruminal starch in total mixed rations at a certain time point, expressed as a percentage (%). W_t is the starch content in total mixed rations, expressed in grams per kilogram (g/kg). Wr is the starch content in the ruminal degradation residue of total mixed rations at a certain time point, expressed in gra

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