Fishy-egg tainting has long been a problem associated with feeding canola meal (CM) to brown-shelled laying hens. It is a classical example of nutrigenetics, as both dietary and genetic factors must be present for a hen to lay fishy-tainted eggs. Trimethylamine (TMA), the compound responsible for the fishy smell, is produced by bacterial fermentation of choline in the lower gut. CM contains large amounts of choline in the form of sinapine. Choline must first be hydrolyzed from sinapine before it can be absorbed or converted to TMA. Normally, the malodourous TMA is metabolized to the odourless trimethylamine N-oxide (TMAO) by flavin-containing monooxygenase 3 (FMO3). A mutation in FMO3 (c.984A>T) prevents TMA from being oxidized to TMAO, and subsequently TMA accumulates in the developing egg yolks. Our objective was to determine the inheritance pattern of fishy-egg tainting when hens are fed canola meal, reflecting typical industry conditions. In the first of two trials, hens of a commercial brown-shelled strain were genotyped at FMO3 c.984A>T and fed graded levels of CM (0, 6, 12, or 18%). These hens were bred to produce a second generation of hens, which were also genotyped and fed graded levels of CM (0, 6, 12, 18, or 24%) or choline chloride (0, 0.055, 0.110, 0.165, or 0.220%). Choline chloride, at levels up to 0.220%, does not lead to the production of fishy tainted-eggs. When fed CM, TT hens laid fishy-tainted eggs. Mean yolk TMA concentration was not significantly different between hens of the AA and AT genotypes, with means from both genotypes remaining below the human detection threshold for all of the dietary treatments. Large day-to-day variations in yolk TMA concentration were seen in hens of all three genotypes. We concluded that fishy-egg tainting is recessive when hens are fed CM at levels reflecting typical commercial practices.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-09152008-112404 |
| Date | 16 September 2008 |
| Creators | Ward, Alison Katherine |
| Contributors | Van Kessel, Andrew G., Schmutz, Sheila M., Laarveld, Bernard, Drew, Murray D., Classen, Henry L. (Hank), Buchanan, Fiona C., Whiting, Susan J. |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-09152008-112404/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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