title: The effects of tannins on nutrient utilisation in the White Pekin duck.
abstract: 1. Two experiments were conducted to determine the effects of tannins on nutrient utilisation in the White Pekin duck. 2. Experiment 1 was a rapid nutrient balance assay to determine the nitrogen (N) retention and metabolisable energy (ME) of maize, low-tannin sorghum (P-954063) (Sorghum bicolor (L). Moench) and high-tannin sorghum (IS-4225) cultivars for ducks. The assay lasted 120 h, with an initial 24 h food-deprivation period, a 48 h excreta collection period for endogenous losses and a 48 h excreta collection period for ingredient losses. The true metabolisable energy (TMEn) content was lower (P<0.05) in the high-tannin sorghum cultivar (13.85 MJ/kg) than the maize (14.94 MJ/kg) and the low-tannin sorghum cultivar (14.39 MJ/kg). True N retention was lower (P<0.05) for the high-tannin sorghum (0.24 g) than for maize (1.33 g) and low-tannin sorghum (1.1 g). 3. In experiment 2, the brush-border membrane vesicles technique was used to determine whether tannic acid caused inhibition of L-threonine transport across duck intestinal brush-border membrane. The brush-border membrane vesicles were mixed with tannic acid solutions (pH 7.4) to give gradient tannic acid concentrations of 0, 0.05, 0.10, 0.25, 0.50, 1.00 and 2.50%. As a fraction of the control (no tannic acid), the maximal inhibition of L-threonine transport (Imax) under the sodium-gradient condition was 77.10% (P<0.05). Under the sodium-free condition, the maximal inhibition of L-threonine transport (Imax) was 45.15% (P<0.05). 4. These results demonstrated that nutrient utilisation in the White Pekin duck was lower from the high-tannin sorghum cultivar than from the low-tannin sorghum cultivar. The results also suggested that the antinutritive effects of tannins in foodstuffs are due partly to their inhibitory action on intestinal brush-border bound amino acid transporter proteins.
authors.affiliation: Purdue University, USA.
authors.forename: D
authors.initials: D
authors.lastname: King
authors.forename: M Z
authors.initials: MZ
authors.lastname: Fian
authors.forename: G
authors.initials: G
authors.lastname: Ejeta
authors.forename: E K
authors.initials: EK
authors.lastname: Asem
authors.forename: O
authors.initials: O
authors.lastname: Adeola
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002151:Calorimetry / Q000662:veterinary; D004372:Ducks / Q000378:metabolism*; D002523:Edible Grain / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D047348:Hydrolyzable Tannins / Q000494:pharmacology*; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012964:Sodium / Q000502:physiology; D013634:Tannins / Q000008:administration & dosage* / Q000378:metabolism; D013912:Threonine / Q000493:pharmacokinetics; D003313:Zea mays / Q000378:metabolism
chemical_list: D047348:Hydrolyzable Tannins; D013634:Tannins; D013912:Threonine; D012964:Sodium; D009584:Nitrogen