|RANATHUNGA, SANJEEWA - South Dakota State University|
|ANDERSON, JILL - South Dakota State University|
|HERRICK, KEVIN - South Dakota State University|
Submitted to: Animal Feed Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2017
Publication Date: 4/1/2017
Citation: Ranathunga, S.D., Kalscheur, K., Anderson, J.L., Herrick, K.J. 2017. Evaluation of a modified method to measure total starch in animal feeds. Animal Feed Science and Technology. 226:124-132.
Interpretive Summary: The AOAC sets standardized methods for chemical analysis, and AOAC method 996.11 has been recognized as an accurate, repeatable, and efficient method to measure total starch in animal feeds. However, analyzing starch using the AOAC method can be expensive and associated with technical challenges. Modification of the AOAC method was done by combining the AOAC method with the acetate buffer method and using a-amylase and amyloglucosidase concentrations from alternative sources. Different samples with varying starch concentrations were analyzed for starch concentrations using the AOAC method and modified AOAC method. The results suggest that the modified AOAC method was comparable to AOAC method. The modified method could be considered a more cost effective, environmental friendly and less technically challenging method compared with the AOAC method.
Technical Abstract: The AOAC method 996.11 has been recognized as an accurate, repeatable, and efficient method to measure total starch in animal feeds. However, analyzing starch using the AOAC method can be expensive and associated with technical challenges. The objective of this study was to determine if an alternative modified starch method (MAOAC) could be more economical and alleviate technical challenges associated with the AOAC method. Average starch concentration for 9 samples analyzed: rumen sample, fecal sample, alfalfa, dried distillers grains with solubles, corn silage, TMR, concentrate mixture, dry corn, and pure corn starch was not affected by method (AOAC method = 298.7±1.84; MAOAC = 298.0±1.39 g kg-1; P = 0.49), technician (technician I = 297.8±12.8 g kg-1; technician II = 299.0±19.6 g kg-1; P = 0.24), or run (run I = 298.4±15.3 g kg-1; run II = 298.1±17.0 g kg-1; P = 0.59). The average time spent to analyze 18 samples was approximately 3 hours for both methods. Average cost per sample assayed with the MAOAC method was $0.84 compared with $3.40 for the AOAC method. There was a 79% decrease in water consumption for the samples containing >100 g kg-1 starch with the MAOAC method compared with the AOAC method. The MAOAC starch assay could be considered a cost effective, environmentally friendly, and less technically difficult method compared with the AOAC starch method.