• Food Science of Animal Resources
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• v.22 no.3
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• pp.252-258
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• 2002

The objective of the study was to investigate the effects of dietary conjugated linoleic acid (CLA) on the egg quality. The ISA Brown (200 days and 500 days) hens were assigned randomly to six diets containing 0, 0.6, 1.2, 1.8, 2.4 and 4.8% CLA, respectively. The CLA contents was not detected in control eggs, whereas the CLA contents of eggs that fed with CLA diets was significantly increased (p.0.05) as increasing of dietary CLA levels and feeding periods. Eggs weight, Haugh unit (HU), shell color, shell weight, shell density, and shell thickness were not significantly different among treatments. However, the albumen height from hens fed CLA was significantly (P<0.05) lower than those of control at 7 weeks. As increasing of the CLA levels in diet, the rate of saturated fatty acid in egg yolk was increased and yolk color showed more yellow color. Especially, T4 showed significantly (P<0.05) more yellow color than those of control in yolk color. When e99s were boiled, egg yolks from CLA dietary groups showed significantly (p<0.05) higher hardness value than control.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.427-442
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• 2002

Conjugated linoleic acid(CLA) is a collective term for a group of positional (c8, c10; c9, c11; c10, c12, and c11, c13) and geometric(cis,cis; cis,trans; trans,cis; and trans,trans) isomers of octadecadienoic acid (linoleic acid) with conjugated double bond system. CLA has been shown to have a variety of biological effects. Major effects of CLA on health, such as anti-cancer, anti-oxidation, anti-atherosclerosis and improving immuno-responses, might be derived or partially derived from the alternated lipid metabolism after CLA feeding. Most of studies on the effect of CLA on fat metabolism are concentrated on rats, mice, pigs and other mammals. The CLA inhibited carcinogen-induced neoplasia in several animal models and inhibited the proliferation of human malignant melanoma, colorectal and breast cancer cells and CLA reduced the atherosclerosis. Several studies have determined the antioxidant property of CLA; however, the property still remains controversial. Some of the studies have shown that CLA acted as an antioxidant, whereas some other studies have demonstrated that CLA might be a prooxidant. Several studies suggested that CLA could reduce fat accumulation in mammals. CLA was suggested to promote muscle growth and reduce fat deposition in mouse, and improve feed efficiency in rats. CLA has been shown to inhibit the activity of stearoyl-CoA reductase. CLA also reduced the content of arachidonic acid. Since arachidonic acid, and eicosapentaenoic acid (EPA) and docosahexenoic acid (DHA) are synthesized by different pathways, reducing the synthesis of arachidonic acid may not mean reducing that of EPA and DHA. Many sutdies have been shown biological effects of CLA. Therefore, further research is needed to answer the following questions: 1) how to synthesize the new CLA by new methods, 2) why CLA has shown biological effects, 3) how to increase CLA effects in animal products.

• Journal of Nutrition and Health
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• v.36 no.3
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• pp.270-279
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• 2003

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of linoleic acid (LA) and exhibits anticarcinogenic activity in a variety of animal models. We have previously observed that CLA inhibited the growth of Caco-2 cells, a human colon adenocarcinoma cell line. The present study was performed to determine whether the growth inhibitory effect of CLA is related to change in secretion of IGF- II and/or IGF-binding proteins (IGFBPs) that have been shown to regulate Caco-2 cell proliferation by an autocrine mechanism. Cells were incubated in serum-free medium with various concentrations of CLA or linoleic acid (LA). Immunoblot analysis of 24-hours, serum-free, conditioned medium using a monoclonal anti-IGF-IIantibody revealed that Caco-2 cells secreted both mature 6,500 Mr and higher Mr forms of pro IGF-II. The levels of pro IGF-II and mature IGF-IIwere decreased by 43 $\pm$ 2% and 53 $\pm$ 6%, respectively by treatment with 50 $\mu$ M CLA. LA slightly increased pro IGF- II levels. Results from Northern blot analysis showed that CLA decreased IGF-II mRNA levels at 50 $\mu$ M concentration suggesting that CLA regulation of IGF-II protein expression occurs partly at the transcriptional level. Ligand blot analysis of conditioned media using 1251-IGF-II revealed that CLA slightly decreased IGFBP-2 levels and increased IGFBP-4 levels. We confirmed our previous results that CLA inhibited cell growth in a dose-dependent manner but LA slightly increased cell growth. Exogenous IGF-II mitigated the growth inhibitory effect of CLA. These results indicate that the growth inhibitory effect of CLA may be at least in part mediated by decreasing IGF-II and IGFBP-2 secretion and increasing IGFBP-4 secretion in Caco-2 cells.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.111-114
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• 2003

Conjugated linoleic acid (CLA), known to possess various beneficial effects such as anticarcinogenic, antioxidative, and cholesterol-depressing, has been used as a health supplementary food in Japan and the USA. Optimum condition for CLA production without causing changes in quality of kimchi was determined using Bifidobacterium sp., a CLA-producing microorganism, as a starter in culture broth, freeze-dried culture, and encapsulated culture. Results revealed encapsulation was most ideal for maintaining the ability of bacterium to produce CLA during kimchi fermentation. Exogenous linoleic acid (LA) which is a substrate for conversion to CLA was not added to kimchi since LA was already exists in red pepper. Changes in sensory properties of kimchi and production of CLA were measured after inoculation of the encapsulated starter. The optimum inoculation concentration of the encapsulated starter was 0.1% (w/w) for production of CLA without causing changes in kimchi taste.

• Food Science of Animal Resources
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• v.28 no.4
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• pp.451-456
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• 2008

This study was conducted to determine the effects of dietary supplementation with conjugated linoleic acid (CLA) feeding levels (0, 0.5, 1.0, 1.5, and 2.0%) on the carcass characteristics, growth performance, serum cholesterol, and fatty acid in thigh of chicken meat. Two hundred broiler (Arbor Acre Broiler, male) were randomly assigned to five groups and were fed for five weeks and slaughtered. Thigh muscle was used for determining fatty acid composition. There was no significant difference in growth performance, such as weight gain, feed intake and feed conversion by CLA levels. Among carcass characteristics, percentage of carcass, thigh, breast, and drumstick was not influenced by the dietary CLA levels, but abdominal fat was significantly reduced with the increased CLA amount in the broilers diets (p<0.05). Higher CLA levels increased HDL-C and reduced total cholesterol and LDL-C (p<0.05). As the dietary CLA levels increased, muscular palmitic acid (saturated fatty acid) levels was increased, but the rates of oleic acid, linoleic acid, and arachidonic acid (unsaturated fatty acid) were decreased. In addition. CLA isomers were linearly increased with the increase in dietary CLA levels (p<0.05). As a conclusion, 2% of CLA feeding is possible to maximize accumulation of CLA in meat, but changes in fatty acid composition is not profitable. Therefore, 1% of CLA feeding i,j considered to be proper for accumulation of CLA and minimization of the change in fatty acid.

• Nutrition Research and Practice
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• v.2 no.4
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• pp.326-330
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• 2008

Conjugated linoleic acids (CLA) were identified in 1980's, since then it has been intensively studied due to its various beneficial health effects such as anti-inflammatory, anti-atherogenic, anti-carcinogenic and anti-diabetic/obesity effects. Isomer specificity of a number of CLA isomers, especially predominant isomer 9Z,11E- and 10E,12Z-CLA, is now recognized. However, the less prevalent CLA isomers have not been well characterized. Recently, studies have reported the distinctively different effects of 9E, 11E-CLA in colon cancer cells, endothelial cells, and macrophage cells compared to the rest of CLA isomers. In this review, various effects of CLAs, especially anti-inflammatory and anti-atherogenic effects, will be discussed with focusing on the isomer-specific effects and potential mechanism of action of CLA. At last, recent studies about 9E,11E-CLA in in vitro and animal models will be discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1348-1352
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• 2004

More than 200 Bifidobacterium sp. originated from human intestine were investigated for their ability to produce conjugated linoleic acid (CLA). Of the Bifidobacteria tested, 1 of culture type strain and 12 isolated strains from Korean infants showed CLA producing ability. cis-9, trans-11 octadecadienoic acid presented more than 90% of the total CLA isomers produced by the Bifidobacteria. CLA content in fermented milk by Bifidobacterium sp. KHU 141 increased by 39.6 mg/l00 g, which showed the potential use for producing fermented milk containing high content of CLA. In fermented milk, little changes showed in lauric acid, myristric acid, palmitic acid, oleic acid, and linolenic acid contents, whereas the content of linoleic acid (LA) decreased and the content of CLA increased. Bifidobacterium sp. KHU 141 converted 86.0% and 84.8% of LA consumed to CLA for 24 hr and 48 hr fermentation, respectively. Prolonging incubation from 24 to 48 hours did not appear to enhance CLA formation and CLA producing ability was stable whether bottle, test tube, or fermenter was used for making fermented milk by Bifidobacterium sp. KHU 141.

• Preventive Nutrition and Food Science
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• v.5 no.1
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• pp.10-14
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• 2000

A simple and rapid method was developed to prepare a large quantity of highly pure conjugated linoleic acid (CLA) chemically-synthesized from safflower seed oil (SSO). CLA-SSO(74.9% in purity) was synthesized from fresh SSO(79.9% of linoleic acid) by alkaline isomerization at 18$0^{\circ}C$. Urea(50g) and CLA-SSO (25g) were completely dissolved in ethanol (750ml) using a water bath(5$0^{\circ}C$) and followed by refluxing for 60 min. The resultant was cooled to room temperature and stored in a cold room (4$^{\circ}C$) for 24hrs. After removing the urea adduct by filtration, the filtrate was rotoevaporated under 4$0^{\circ}C$ and the residue was dissolved in hexane (200ml). The hexane extract was washed with distilled water (100ml$\times$3) and dried over sodium sulfate anhydrous. This urea treatment procedure was repeated three times. The purity of CLA recovered from the hexane extract was 95.0%. This method can be applied to prepare a large quantity of highly pure chemically-synthesized CLA (>0.5kg/a batch) from any plant oils containing high percentages (>70%) of linoleic acid.

• Food Science of Animal Resources
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• v.30 no.6
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• pp.879-885
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• 2010

Conjugated linoleic acid (CLA) isomers are found naturally in foods, such as milk, milk products, beef and others, from biohydrogenation of vegetable oils. They are heterogenous group of isomers of linoleic acid in the family of polyunsaturated fatty acids. Among the isomers of linoleic acid cis9, trans11- CLA (c9, t11-CLA) and trans10, cis12- CLA (t10, c12-CLA) are found to be biologically active isomers. These biologically active isomers either individual or combined found to be health beneficial in various diseases, such as cancer, diabetes, obesity, and atherosclerosis, conclusive participation in physiological processes are necessary. This review focused on the current study of CLA in prevention of disease, such as cancer, diabetes and atherosclerosis, and their effective function in body fat reduction, improvement of bone and muscle mass at a cellular, clinical and systematic level.

• Journal of Nutrition and Health
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• v.36 no.3
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• pp.280-286
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• 2003

Conjugated linoleic acid (CLA) consists of several geometric isomers of linoleic acid. CLA is found in foods derived from ruminants and exhibits strong anticarcinogenic effects in a variety of animal models. Matrix metalloproteinases (MMPs) play a key role in cancer progression. Specifically, MMP-2 and -9, which hydrolyze the basal membrane type IV collagen, are involved in the initial breakdown of collagen and basement membrane components during tumor growth and invasion. However, the effects of CLA on cancer cell motility and MMP expression and activity are not currently well known. Therefore, the present study examined whether CLA reduces the activity of MMP and cell motility in SW480 and SW620 cells, the human colon cancer cell lines. Gelatin zymography and Western blot analysis revealed that phorbol 12-myristate 13-acetate (PMA) induced the activity and protein expression of Mr 92,000 MMP-9 in both cell lines. To examine whether CLA inhibits the MMP activity, cells were incubated with 100 ngfmL PMA in the presence of various concentrations of CLA. PMA-induced MMP-9 activity was decreased by 20 $\mu$ M CLA in SW480 cells, and by 10 $\mu$ M and 20 $\mu$ M CLA in SW620 cells. Results from the Hoyden chamber assay showed that cell motility was increased by PMA and that PMA-induced cell motility was significantly decreased by 20 $\mu$ M CLA in SW480 cells. These results indicate that CLA may reduce the motility and MMP activity in human colon cancer cells.