Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/19974
Title: The effect of dietary calcium inclusion on broiler gastrointestinal pH: Quantification and method optimization
Contributor(s): Morgan, Natalie  (author)orcid ; Walk, C L (author); Bedford, M R (author); Burton, E J (author)
Publication Date: 2014
Open Access: Yes
DOI: 10.3382/ps.2013-03305Open Access Link
Handle Link: https://hdl.handle.net/1959.11/19974
Abstract: There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed 1 of 2 experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d posthatch. Dietary Ca content had no significant effect on in situ pH, but it contributed toward variance in ex situ pH of both gizzard and duodenum digesta. Digesta pH read higher when the digesta was removed from the tract, but the amount of time the digesta was exposed to air did not affect the reading. Digesta pH read higher when measured at room temperature than when measured at 41°C; temperature made the strongest unique contribution to explaining variance in duodenum pH, and the second strongest contribution to explaining variance in gizzard pH, after diet. When water was added to the digesta, before pH determination, the pH of the digesta read higher (P < 0.001) than when measured in situ. The method that resulted in pH readings that were most representative of bird gastrointestinal environment was insertion of a pH probe directly into the gut lumen posteuthanasia, because measurement ex situ likely encourages dissociation of carbonic acid, the major buffer in the gastrointestinal tract, which causes pH to read to be higher than when measured in situ. This study shows that the method of pH measurement needs careful consideration to ensure the validity of the result.
Publication Type: Journal Article
Source of Publication: Poultry Science, 93(2), p. 354-363
Publisher: Oxford University Press
Place of Publication: United States of America
ISSN: 1525-3171
0032-5791
Fields of Research (FoR) 2008: 070204 Animal Nutrition
Fields of Research (FoR) 2020: 300303 Animal nutrition
Socio-Economic Objective (SEO) 2008: 839999 Animal Production and Animal Primary Products not elsewhere classified
Socio-Economic Objective (SEO) 2020: 109999 Other animal production and animal primary products not elsewhere classified
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Appears in Collections:Journal Article
School of Environmental and Rural Science

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