Influence of dietary menhaden oil on egg yolk lipids

Jenn-Horng Fred Lin, Purdue University

Abstract

Interest in health effects of n-3 polyunsaturated fatty acids has stimulated studies of the dietary fish oil on egg yolk lipids. The first work presented in this thesis was to investigate the effect of feeding the menhaden oil diet on egg yolk cholesterol concentration during the laying cycle. Eggs from hens fed with 1.5% menhaden oil exhibited a mean reduction of 19% cholesterol content compared to the controls (1.5% corn oil). Data also indicated that length of feeding time influenced egg cholesterol content. The second experiment was to examine the fatty acid composition of eggs influenced by two dietary lipids, menhaden and corn oil. Changes of dietary fats tended to produce a fatty acid pattern in eggs similar to that of the diet and varies with the oil source concentration. Most of the fatty acid in eggs were altered within 15 days of feeding. Egg yolk cholesterol analyzed by the colorimetric or G.C. methods were examined. Significantly different results but similar change pattern of egg cholesterol levels between these two methods were found. The differences in lipid extraction solvents, saponification precedures or n-3 PUFAs in eggs might be factors which contributed to the discrepancy. Finally, the feeds containing fish oil sources were studied the quality when stored at various condition. The diet kept at 4$\sp\circ$C with 0.04% TBHQ in the fish oil was found to extend the oxidation induction period for at least 2 weeks. If possible, the fish oil diets are better to be prepared every week and stored frozen, preferably at 4$\sp\circ$C or below.

Degree

Ph.D.

Advisors

Pratt, Purdue University.

Subject Area

Food science|Livestock|Nutrition

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