Trimethylamine Production in the Caeca and Small Intestine as a Cause of Fishy Taints in Eggs

Abstract

The caeca and small intestine of chickens consistently contain trimethylamine (TMA). The caecal contents in the birds studied ranged from 4 to 55 Mg TMA/g and contained the higher concentrations when the diet contained rapeseed meal or supplementary choline. The amounts of TMA in the small intestine were lower (1 to 21 jug/g) and were less influenced by dietary composition. Supplementary choline in the diet of laying birds induced the production of tainted eggs by some birds. The yolks of tainted eggs contained concentrations of TMA which were consistent for each bird. TMA was also present in the follicular yolks of all sizes in the ovaries of birds which laid tainted eggs. It is postulated that, in birds laying tainted eggs, failure of the liver to oxidize TMA is responsible for deposition of TMA in egg yolk.

Nutritional and physiological effects of rapeseed meal sinapine in broiler chickens and its metabolism in the digestive tract

“…33 Choline availability from RSM in avian species is reported to be half of that found for soybean meal. 38 This may be explained by the lower SNP digestibility of RSM found in this research as well as a more distal location of SNP hydrolysis in the small intestine.…”

Scientific Opinion on safety and efficacy of choline chloride as a feed additive for all animal species

“…Choline chloride is in the wide range (90 mg/kg diet for three weeks up to 1800 mg/kg) without any influence on the performance of laying hens and on hatchability of eggs (Jeroch et al, 1991). In another study (March and MacMillan 1979) the adverse effect of supplementing 3834-5228 mg choline chloride/kg diet affected product quality (fishy taint of some eggs).…”

FUNCTIONAL EGG PRODUCTION. I. THE ROLE OF ω-3 POLYUNSATURATED FATTY ACIDS (review)

“…However, in none of the studies TMA has yet been identified as the main cause of fishy smell. It was reported that in hens with trimethylaminuria, breathing often have this smell [76], but this fact has not been noted in papers reporting findings in enriching eggs with PUFAS.…”

“…is released when the fish products are naturally spoiled, are the only well-studied substance that causes a truly fishy smell of eggs [75]. TMA is a product of some microorganisms of the distal part of the small intestine (including cecums) in chickens [76]. There are chicken genotypes predisposed to fishy smell of eggs due to the high frequency of A-T single-nucleotide polymorphism in exon 7 of FMO3 (flavin-containing monooxygenase 3) gene; interestingly, this recessive mutation is found almost exclusively in brown laying hens [77].…”