title: Evaluation of free water and water activity measurements as functional alternatives to total moisture content in broiler excreta and litter samples.
abstract: Litter moisture contents vary greatly between and within practical poultry barns. The current experiment was designed to measure the effects of 8 different dietary characteristics on litter and excreta moisture content. Additionally, free water content and water activity of the excreta and litter were evaluated as additional quality measures. The dietary treatments consisted of nonstarch polysaccharide content (NSP; corn vs. wheat), particle size of insoluble fiber (coarse vs. finely ground oat hulls), viscosity of a nonfermentable fiber (low- and high-viscosity carboxymethyl cellulose), inclusion of a clay mineral (sepiolite), and inclusion of a laxative electrolyte (MgSO4). The 8 treatments were randomly assigned to cages within blocks, resulting in 12 replicates per treatment with 6 birds per replicate. Limited effects of the dietary treatments were noted on excreta and litter water activity, and indications were observed that this measurement is limited in high-moisture samples. Increasing dietary NSP content by feeding a corn-based diet (low NSP) compared with a wheat-based diet (high NSP) increased water intake, excreta moisture and free water, and litter moisture content. Adding insoluble fibers to the wheat-based diet reduced excreta and litter moisture content, as well as litter water activity. Fine grinding of the oat hulls diminished the effect on litter moisture and water activity. However, excreta moisture and free water content were similar when fed finely or coarsely ground oat hulls. The effects of changing viscosity and adding a clay mineral or laxative deviated from results observed in previous studies. Findings of the current experiment indicate a potential for excreta free water measurement as an additional parameter to assess excreta quality besides total moisture. The exact implication of this parameter warrants further investigation.
authors.affiliation: Cargill Animal Nutrition, Veilingweg 23, NL-5334 LD Velddriel, the Netherlands evelien_hangoor@cargill.com.
authors.forename: E
authors.initials: E
authors.lastname: van der Hoeven-Hangoor
authors.affiliation: Animal Nutrition Group, Wageningen University, PO Box 338, NL-6700 AH Wageningen, the Netherlands;
authors.forename: C J
authors.initials: CJ
authors.lastname: Rademaker
authors.affiliation: Cargill Animal Nutrition, 10 Nutrition Way, Brookville, OH 45309.
authors.forename: N D
authors.initials: ND
authors.lastname: Paton
authors.affiliation: Animal Nutrition Group, Wageningen University, PO Box 338, NL-6700 AH Wageningen, the Netherlands;
authors.forename: M W A
authors.initials: MW
authors.lastname: Verstegen
authors.affiliation: Animal Nutrition Group, Wageningen University, PO Box 338, NL-6700 AH Wageningen, the Netherlands; Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, NL-3584 CL Utrecht, the Netherlands.
authors.forename: W H
authors.initials: WH
authors.lastname: Hendriks
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000822:Animal Husbandry; D000818:Animals; D018554:Avena / Q000737:chemistry; D002645:Chickens / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D004043:Dietary Fiber / Q000032:analysis; D004326:Drinking; D005243:Feces / Q000737:chemistry*; D054368:Laxatives / Q000378:metabolism; D017633:Magnesium Silicates / Q000378:metabolism; D008278:Magnesium Sulfate / Q000378:metabolism; D010316:Particle Size; D011134:Polysaccharides / Q000008:administration & dosage / Q000378:metabolism; D011897:Random Allocation; D014908:Triticum / Q000737:chemistry; D014783:Viscosity; D014867:Water / Q000032:analysis* / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry
chemical_list: D004043:Dietary Fiber; D054368:Laxatives; D017633:Magnesium Silicates; D011134:Polysaccharides; D014867:Water; D008278:Magnesium Sulfate; C001671:magnesium trisilicate
keywords: broiler; excreta moisture; feed composition; litter moisture; water activity