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Is Quail Egg’s Cholesterol High?

William H.P. Ho

                                                                                      Abstract:

This article is to summarize the work done by Dr. Ho Hon Fatt (1999) on the research in the cholesterol level of quail egg in Singapore’s quail farm. Being local and a scientific laboratory research, it is the best evidence to clear all misunderstanding of quail egg being very high in cholesterol.

The misunderstanding of quail egg being very high in cholesterol had been very confusing and disturbing for the farmer and also the public. Quail egg to the European is known as the “Vitamin Bomb” (Poultry international, 1990), which is very rich (at least 6 time more than chicken egg) in vitamin, protein and minerals. The goodness of the eggs is not appreciated due to the misunderstanding. The challenge was champion by a researcher in the Primary Production Department of Singapore, which now known as the Agri-food & Veterinary Authority of Singapore, Dr. Ho Hon Fatt in 1998. An initial test was done in one of the local farm, using only a sample of 15 quail eggs which verify the cholesterol level was indeed lower than other results reported in overseas countries. This finding justifies the purpose in a larger research with larger sample and not only for the cholesterol level but with the correlation between age, egg sizes and cholesterol contents.

The sample was from a quail layer population of 47,500 female quail layers with the daily production of about 38,000 eggs. The breed of the quail was a crossbred Japanese quail (Coturnix Japonica). The farm housed the quail in a steel shed, inside it with two rows of each 200 feet long with four tiers of battery cages. Each unit of the cage measure 22” X 10” X 8” which contain fifteen quails in it. The Quails were fed with commercial layer rations. Eggs were collected from the different age group of one, three, five, seven and eleven months on five morning over two week period in February 1998. The farm had the age group properly labeled which each specific cage of eggs from each age group were selected and thus collection of all eggs were taken at the appointed time. The 15 quails laid eggs but not at appointed time, therefore only 10, 13, 11, 10 and 10 eggs belonging to the 3, 5, 7, 9, and 11 month age groups respectively, were collected. The total of 54 eggs were collected and taken immediately to the PPD’s food laboratory for analysis. In the laboratory, the eggs were weighed individually then cracked open and the yolk separated from the white and weighed. The cholesterol in the yolk was extracted by methanolic potassium hydroxide. Cholesterol content was then determined by the High Performance Liquid Chromatography (HPLC) method using a reversed-phase column with a mobile phase of acetonitrile/ isopropanol and measurements taken at wave length 210nm.

 The results were tabulated in table 1, attach in the appendix of this article. The arithmetric mean of the cholesterol content of the 54 eggs measured was 46.3mg per quail egg. Table 2 summarize the analysis of the coefficient of correlation ( r ) was carried out for the six parameters: age/ egg size, age/ egg yolk, age/ cholesterol whole egg, egg size/ cholesterol whole egg and egg size/ cholesterol per g yolk. The result shows they were all significantly correlated. Thus the older the quail, the larger was the size of the eggs; and the heavier the weight of the egg yolk, the higher was the cholesterol content in terms of mg per gram yolk.

It was found that among 54 quail eggs collected; only one egg had a double egg yolk which belongs to the 11-month old age group. The cholesterol content in this egg was 108.51mg. This was confirm with the experience of the farmer, that the double egg yolk is usually found in older quail of the farm. Table 3 was the summarises of publish information in three countries and from one pharmaceutical company, pertaining to cholesterol content in quail eggs. Table 4 similar are summarise data published in the journal Poultry Science.

From the table 3 and 4 we can observe that there different expression in units: mg/ 100g egg, mg/ 100g yolk, mg/ g yolk and mg/ g egg. With so many different way of expression, which easily confuse people in drawing the wrong conclusion in the content of cholesterol in quail eggs. Yolk and whole egg is completely different which 100g of yolk required many whole eggs to be obtained. Average the quail egg weigh only about 10 gram. The commercial source when converted into mg/ egg, it read 364mg/ egg which are still higher than the figure of 46.3 reported in the present research. The reason for the discrepancies might have been inadvertently selected for producing a high level of cholesterol in the egg yolk. Results of surveys reported in the seventies seem to support this view. A more acceptable explanation is that the cholesterol content of eggs has been overestimated using a common colorimetric method (Beyer and Jensen, 1989). For example, the latest nutritional analysis by the USDA shows that a hen egg has about 213mg of cholesterol which is much lower than the previous value of 274 mg cited in the USDA Agricultural Handbook 1976. Analysis by HPLC is now the method of choice in better equipped laboratories.

The research conclude that the cholesterol content of average 10gram is much lower than previously reported by other researchers and found that the cholesterol is higher in larger egg. With the practice of culling quails older than 10 months, the produce quail eggs will be within the weight range of 10 ± 1 gram and having average cholesterol 46.3mg / whole egg.

Reference

Ho, H. F., 1999. Singapore Primary Industry Journal 27: 55-58 1999.

Poultry International,1990.

Appendix