الفهرس 
Fatty acidsOnly 14 pages are availabe for public view
 |  | from | 186 |  |  |
| | | from | 186 | | |
Abstract
This study was carried out to investigate the protective effect of blended vegetable oils, consists of chia seed and sunflower oils, with varying ratios of n-6/n-3 polyunsaturated fatty acids (PUFAs), on lipid profile, liver functions, adipocyte functions. and evaluating the hepatic bioconversion of alpha-linolenic acid (ALA,18:3, n-3) to eicosapentaenoic acid (EPA, 20:5, n-3) and docosahexaenoic acid (DHA, 22:6, n-3), in rats with or without having high-fat diet.
The data of this study can be summarized as follows:
1st: Physical and chemical characteristics of chia seed and sunflower oils:
Physiochemical properties of chia seed and sunflower oils showed that:
Specific gravity 0.93, color (red) 0.75, refractive index 1.48, acid value 1.03(mgKOH/g oil), saponification value 194.05 (mgKOH/g oil), ester value 193.02, iodine value 189.5 (gI2/100g oil), peroxide value 0.85 (meq oxygen/kg), total unsaponifible matter 1.22%, and stability induction period at (120◦C in hour), 3.94 are the values associated with chia seed oil. While sunflower oil has refractive index 1.47, color (red) 0.95, specific gravity 0.92, acid value 1.27 (mgKOH/g oil), saponification value 191.91(mgKOH/g oil), ester value 190.64, iodine value 120.6 (gI2/100g oil), peroxide value 0.76 (meq oxygen/kg), total unsaponifible matter 2.15% and stability induction period at (120◦C in hour) 4.86.
2nd: Sterols and fatty acids composition of chia seed and sunflower oil:
A- GC.MS fractionation of sterols in chia seed and sunflower oils showed that:
Chia seed oil contains β-sitosterol as the main sterol which reached 46.61%, followed by stigmasterol 19.55%, campesterol 16.93%, then delta-5-avenasterol 10.2%, and lanosterol 6.71%. While sunflower oil contains β-sitosterol as the main sterol which reached 57.63%, followed by delta-7-stigmasterol 15.02%, stigmasterol 9.7 %, then campesterol 9.5 %, delta-7-avenasterol 4.25%, and delta-5-Avenasterol 3.9%
B- GC fractionation of fatty acids in chia seed and sunflower oils showed that:
Chia seed oil contains alpha-linolenic acid as the main fatty acid which reached 61.29%, followed by linoleic acid 18.35%, then oleic acid 8.49%, and finally palmitic and stearic acid (6.71% and 4.39%, respectively). While sunflower oil contains linoleic acid as the main fatty acid which reached 55.87%, followed by oleic acid 25.71%, then palmitic acid 10.09%, and finally stearic, gama-linolenic and alpha-linolenic acid (4.88%, 2.11% and 0.93% respectively).
3rd: Biochemical evaluation of the effect of different n-6/n-3 PUFAs ratios diets on lipid profile, liver functions, and adipocyte functions in rats that were fed a high-fat diet.
This experiment was designed to evaluate the effect of different n-6/n-3 PUFAs ratios diets (1:1, 5:1, and 10:1) on lipid metabolism and liver functions in rats that were fed a high-fat diet for 10 weeks.
The obtained results can be summarized as follows:
1- All studied groups of 1:1, 5:1, and 10:1 n-6/n-3 PUFAs ratios diets lowered significantly body weight gain, weight of tested organs: liver, kidneys, and heart of rats, serum triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), very low-density lipoprotein cholesterol (vLDL-c), risk ratio, atherogenic index, adiponectin (ADPN) levels, and lipoprotein lipase (LPL) activity than those of the positive control group and the lowest values of them were for 1:1group then 5:1 and 10:1 groups.
2- Serum vLDL-c, ADPN, free fatty acids (FFA) and LPL levels in the 1:1 and 5:1 groups were significantly lower than those in the 10:1, negative and positive control groups and the lowest of them was those of 1:1 group.
3- The 10:1 group had significant high levels for serum high-density lipoprotein cholesterol HDL-c, FFA and ADPN levels than those in the negative control group.
4- All studied groups of 1:1, 5:1, and 10:1 n-6/n-3 PUFAs ratios diets had significant high values for serum leptin levels compared with positive and negative control groups and the highest of them was that of 10:1 group then 5:1 and 1:1 groups.
5- Positive control group was exposed to be hyperlipidemic group which led to significant increase in the enzymes activities of liver functions aspartate transaminase (AST), alanine transaminase (ALT), lactate dehydrogenase (LDH) activities and alkaline phosphatase (ALP), but total protein and albumin contents were significantly decreased. All studied groups of 1:1, 5:1, and 10:1 n-6/n-3 PUFAs ratios diets have a protective effect against hyperlipidemia and improved the activities of AST, ALT, ALP and LDH with increasing total protein and albumin contents than those of the positive control group and the best of them was 1:1group then 5:1 and 10:1 groups.
Blended oils with a low n-6/n-3 PUFAs ratio improved metabolic disorders by regulating lipid metabolism. Consequently, that ratio had favorable effects on metabolic profiles in rats fed on high-fat diet-fed rats specially of the ratio of 1:1 n-6/n-3.
4th: Evaluation the effect of different n-6/n-3 PUFAs ratios diets on the hepatic bioconversion of alpha-linolenic acid to eicosapentaenoic acid and docosahexaenoic acid and investigating also their effects on lipid profile and liver functions, compared to control diet:
The animals were divided into four groups. First fed on standard diet and saved as control group; second group fed on diet contain 1:1 n-6/n-3 PUFAs ratio, third group fed on diet contain 5:1 n-6/n-3 PUFAs ratio and fourth group fed on diet contain 10:1 n-6/n-3 PUFAs ratio by blended oils as oil source. The experiment was carried out for 10 weeks.
The obtained results can be summarized as follows:
1- Blended oils with 1:1 and 5:1 n-6/n-3 PUFAs ratio significantly decreased rat’s body weight gain and weight of organs (liver, heart, and kidney) compared with mixed oils with 10:1 n-6/n-3 PUFAs ratio and control groups and the most influential one was that of 1:1 n-6/n-3 PUFAs ratio.
2- The 1:1 and 5:1 groups showed a significant decrease in serum TG, TC, LDL-c, vLDL-c, risk ratio, and atherogenic index. On the other hand, they showed a significant increase in serum HDL-c compared with 10:1 and control groups and the most effective of them was 1:1 group.
3- The 1:1 group showed a significant decrease in serum AST and ALT activities compared with control, also the 1:1 and 5:1 ratio groups showed significant decrease in serum ALP activity compared with control. On the other hand, the 1:1, 5:1 or 10:1 groups showed significant decrease in serum LDH activity compared with control. Finally, the groups of 1:1 and 5:1 n-6/n-3 PUFAs ratios showed significant increase in serum albumin and total protein levels compared with control.
4- Eiccosapentaenoic acid (EPA, C20:5, omega-3) was detected in the liver’s lipid of the 1:1, 5:1 or 10:1 groups (4.14 %, 2.6%, and 0.05% respectively), while docosahexaenoic acid (DHA, C22:6, omega-3) was detected only in the liver’s lipid of 1:1 and 5:1 groups (3.08% and 1.09% respectively).
It could be concluded that feeding rats on diets rich in ALA, (C18:3, n-3) or have a covenant value of n-6: n-3 ratio such as 1:1 was the most effective in elevating EPA and DHA biosynthesis with improvement of blood lipid profile and liver functions compared with the control group.