EFFECT OF FEEDING DIFFERENT KINDS OF LIPIDS ON CHOLESTEROL LEVELS AND FATTY ACID PROFILES IN JAPANESE QUAIL

Abstract

The effect of three kinds of lipids (fish oil, lard and sunflower oil) at 4% in diet on cholesterol concentration in quail egg, plasma and liver was investigated. Fish oil diet significantly lowered the yolk cholesterol concentration in the starting layer (P<0.05). The yolk cholesterol concentration in quails fed the sunflower oil diet was significantly higher than those in quails fed the fish oil diet and the lard diet after nine weeks feeding. Long term feeding with fish oil did not lower the yolk cholesterol concentration; however, long term feeding with sunflower oil resulted in an increase in the concentration of yolk cholesterol. Nine week·s feeding with sunflower oil significantly lowered plasma total cholesterol and cholesteryl ester concentration; however feeding with fish oil failed to reduce the cholesterol concentration in quail plasma. Feeding the quails with fish oil diet for nine weeks significantly (P<0.05) reduced the total lipid content in quail liver and quails fed the lard diet had the highest liver lipid content comparing to fish oil and sunflower oil diets .. Quails during growing periods had higher cholesterol concentration in liver tissues than during the laving period; the fish oil diet significant, (P<0.05) lowered liver tissue total lipid content and cholesterol concentration compared to the sunflower oil diet Dietary fish oil significantly decreased the the formation of cholesteryl ester in liver. The fatty acid profiles of the dietary lipids were partly reflected in the fatty acid profile in quail egg. plasma and liver. High percentage or ?-3 fatty acids mainly eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA?-3), and docosahexaenoic acid (DHA) in the fish oil diet were easily enriched in yolk lipids and reached peak concentrations after a short period; however, yolk EPA concentration was sensitive to feeding period. and after reaching its highest concentration. after a short period. EPA percentage subsequently decreased significantly. The percentages of DPA ?-3, DHA and total ?-3 fatty acids in total yolk lipids were only affected by the concentrations of these fatty acids in the diets and were not sensitive to feeding duration. High EPA level is difficult to maintain in quail yolk lipids during long term feeding. Eggs laid by quails fed the fish oil diet had higher ?-3 fatty acid level and lower ?-6 fatty acid level at the expense mainly of linoleic acid: the derivation from 20:4?-6 to 22:4?-6 and 22:5?-6 was almost completely inhibited. Eggs laid by quails fed the sunflower oil diet had a higher ro-6 fatty acid level and much lower level of ?-3 fatty 2.cids; EPA could not be detected after five days of feeding the sunflower oil, and the concentration of DHA was significantly reduced. Dietary ro-6 fatty acid inhibited the derivation from 18:3?-3 to EPA and DHA at the expense mainly of EPA, DPA, and DHA The fatty acid profiles in quail abdominal fat is different to the yolk fatty acid profiles in its response to dietary lipids, especially highly derived fatty acids in both omega-3 and omega-6 series is seldom in abdominal fat tissue. Docosatetraenoic acid (22:4?-6) and 22:5?-6 in the quails fed different levels of fish oil and sunflower oil were not detected in abdominal fat: EPA, DPA?-3 and DHA were found in much lower percentages than in yolk The concentration of arachidonic acid in abdominal fat was not readily affected by the dietary lipids. At different stages of yolk development, the recruited follicles takes up different kinds of fatty acid selectively In the early stage, the ovum preferentially take up a high percentage of w-3 fatty acids and polyunsaturated fatty acids rather than saturated fatty acids and monounsaturated fatty acids. The optimum level of dietary fish oil supplementation for Japanese quail is 4% of total diet weight.