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Title:Select novel carbohydrates affect glycemic and insulinemic response, energy value, and indices of gut health as measured using canine, avian, rodent, and in vitro model systems
Author(s):Knapp, Brenda K.
Director of Research:Fahey, George C.
Doctoral Committee Chair(s):Fahey, George C.
Doctoral Committee Member(s):Parsons, Carl M.; Swanson, Kelly S.; Tappenden, Kelly A.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):novel carbohydrates
glycemic response
insulinemic response
energy value
Short Chain Fatty Acid (SCFA)
gut morphology
Abstract:The objective of this research was to evaluate select novel, low-digestible carbohydrates – pullulans (Pull), soluble fiber dextrins (SFD), and soluble corn fibers (SCF) - for properties that could positively impact health outcomes. Study 1 measured in vitro hydrolytic digestion characteristics, glycemic and insulinemic responses, and true metabolizable energy (TMEn) content of select SFDs and Pulls. Soluble fiber dextrins varied in digestibility, with all substrates resulting in low to intermediate in vitro monosaccharide digestion. Pullulans were nearly completely hydrolyzed after simulated hydrolytic digestion. The glycemic response with dogs varied widely among SFDs, with all but one SFD having a lower glycemic response than maltodextrin (Malt). The pullulans all resulted in low glycemic values. Lower relative insulinemic responses (RIR) compared to the Malt control were noted for all SFDs and pullulans. Pullulans resulted in higher true metabolizable energy (TMEn) values than did SFDs. Study 2 measured in vitro hydrolytic digestion, glycemic and insulinemic responses, and TMEn content of SCFs (first and second generation products) produced using different methods. All SCFs had intermediate to low amounts of monosaccharides released as a result of in vitro hydrolytic digestion, with glucose being the primary sugar component released. Second generation SCFs, on average, had lower glycemic responses and TMEn values than did first generation SCFs. Study 3 measured in vitro hydrolytic digestion and glycemic and insulinemic responses of select carbohydrate blends, all containing SCF and blended with Pull, sorbitol (Sorb), and (or) fructose (Fruct). The addition of higher amounts of Fruct and Sorb increased the free Fruct and Sorb concentrations of the blends. All SCF blends resulted in low glycemic and insulinemic responses compared to the Malt control. Blends containing Fruct and Sorb were most effective in attenuating the glycemic and insulinemic responses. Study 4 measured gastrointestinal health outcomes resulting from supplementation of SFD and SCF to rats. Rats were randomly assigned to one of four treatment groups (n=10) for 21 d. An AIN-93G diet with 5% cellulose served as the Control. The 5% cellulose was replaced with either 5% pectin (Pectin, positive control), SFD, or SCF. Consumption of SFD and SCF increased cecal weight but not colon weight. On a per cecum basis, SFD and SCF increased acetate, propionate, and total SCFA concentrations, with no effect on butyrate concentrations, compared to the Control diet. Cecal branched-chain fatty acids (BCFA) concentrations were decreased by SFD and SCF, whereas Pectin increased BCFA concentrations. Supplementation of SFD and SCF did not have an effect on cecal microbial populations compared to the Control diet. Pectin tended to decrease cecal Escherichia coli concentrations. Gut histomorphology was positively affected by SFD and SCF. Increased crypt depth, goblet cell numbers, and acidic mucin were observed in both the cecum and colon of rats supplemented with SFD, SCF, and Pectin. These novel, low-digestible carbohydrates appear to have the potential to beneficially impact health through decreased hydrolytic digestion, attenuated glycemic and insulinemic response, decreased energy value, SCFA production, and modulating gut morphology.
Issue Date:2011-05-25
Rights Information:Copyright 2011 Brenda K. Knapp
Date Available in IDEALS:2011-05-25
Date Deposited:2011-05

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