PSXI-27 - Chemical Composition and In Vitro Fermentation Characteristics of Legumes Using Canine Fecal Inoculum

Legumes are a popular grain-free alternative carbohydrate source in canine diets; however, information on fermentative characteristics of select legumes have not been established. Thus, the objectives of the present study were to quantify the chemical compositions and fermentative profile of select legumes using canine fecal inoculum. Five legume varieties, whole yellow peas (WYP), green lentils (GL), black bean grits, navy bean powder, and garbanzo beans, were analyzed and compared to a control, beet pulp (BP). Substrates were analyzed for gross energy (GE), dry and organic matter, crude protein (CP), acid hydrolyzed fat, and total dietary fiber  fractions, beta-glucans, starch, free and hydrolyzed sugars, and fermentative characteristics: pH, short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), total gas, hydrogen, and methane. Substrates underwent a two-stage in vitro digestion and subsequent fermentation using canine fecal inoculum for 0, 3, 6, 9, and 12 h. Statistical significance was set at P ≤ 0.05. All test substrates contained approximately 8-9% moisture and 4.5 kcal/g GE. Crude protein concentrations of pulses ranged from 21-27%. Insoluble fiber values varied from 17-33%, with soluble fiber values ranging from 0-8%. Total starch content was greatest for GL (58%) and WYP (56%). Sucrose and stachyose were the most predominant free sugars and glucose was the most predominant hydrolyzed sugar among test substrates. Production of SCFA did not differ among substrates after 3 or 6 h of fermentation. BP and WYP had the greatest acetate (1,656 and 1,765 umol/g, respectively) and propionate production values (157.7 and 126.1 umol/g, respectively) after 9 h of in vitro fermentation. Pulses are good sources of dietary protein; however, they are also fiber-rich ingredients that appear to be slowly fermentable in vitro, which may have beneficial implications on the ratios of saccharolytic to proteolytic fermentation towards the distal colon in vivo.