• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.1031-1035
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• 2002

This study was carried out to obtain conjugated linoleic acid (CLA) producing lactic acid bacteria for further study on the enzymes related to the production of CLA which has gained considerable attention and on the development as a probiotic culture. Total 34 lactic acid bacteria were isolated from 19 feces samples of healthy babies. CLA forming ability was measured spectrophotometrically by the modification of linoleate 12-cis, 11-trans-isomerase activity measuring method, and CLA of the cultures were extracted, methylated, and examined by HPLC analysis. CLA methyl ester of only one culture showing the highest value of CLA forming ability could be detected by HPLC analysis. The culture was found to be Gram positive, rods and catalase negative. It grows at $45^{\circ}C$ but not at $15^{\circ}C$, and was identified to be Lactobacillus fermentum on the basis of the biochemical characteristics and the utilization of substrates. These results provide an efficient experimental method to screen CLA producing lactic acid bacteria.

• Preventive Nutrition and Food Science
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• v.6 no.1
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• pp.19-22
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• 2001

Conjugated linoleic acid (CLA) exhibits potent anti-carcinogenic and other biological activities in several animal models. We report here that dietary CLA, chemically synthesized from corn oil, accumulates I silkworm, Bombyx mori, which is used as therapeutic agent for diabetes in Korea and Japan. Mulberry leaves treated with 0.1 or 10% CLA in ethanol were supplied to silkworms from the end of 3rd instar to the 3rd day of the 5th instar. Fresh mulberry leaves or leaves treated with 10% corn oil in ethanol were fed as a check treatment. the amount of total lipids in the larval body ranged from 17.4 to 19.1mg/g of body tissue, which was not significantly affected by the source of the diets. No CLA was found in the control silkworms. But the level of CLA significantly increased to 83.5 mg/g of fat, when fed with mulberry leaves treated with 10% CLA. Only trace amounts of CLA were detected in the larvae reared with check leaves and 0.1% CLA-treated leaves. Mulberry leaves treatd with corn oil or CLA were not palatable to the larvae, resulting in a reduction of larval weight. These results suggest that silkworms containing CLA in body lipids could be producted by dietary CLA.

• Journal of Nutrition and Health
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• v.35 no.10
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• pp.1038-1044
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• 2002

The study was designed to observe the effect of conjugated linoleic acid (CLA) on tumor incidence, eicosanoid formation and antioxidant enzyme activities in colonic mucosa and the fecal excretion of deoxycholic acid and lithocholic acid in 1,2-dimethylhydrazine (DMH)-treated rats. One hundred twenty male Sprague Dawley rats were divided into 2 groups, BT (beef tallow diet) group and FO (fish oil diet) group, and each group was again subdivided into 2 groups depending on CLA supplementation, i.e.4 groups of BT, BTC, FO, FOC. All rats were fed experimental diet for 30 weeks, which contained 12% (wt/wt) total dietary fat including 1% (wt/wt) CLA, and were intramuscularly injected with DMH for 6 weeks to give total dose of 180 mg/kg body. CLA-supplemented to BT and FO diet reduced tumor incidence, eicosanoid (PGE$_2$ and TXA$_2$) level in colonic mucosa. N-3 fatty acids (mainly DHA) of fish oil diet (FO, FOC group) also reduced tumor incidence and significantly reduced eicosanoid (PGE$_2$ and TXA$_2$) level in colonic mucosa. CLA supplementation and n-3 fatty acid significantly increased colonic mucosal level of superoxide dismutase and glutathione peroxidase activities but reduced secondary bile acids (deoxycholic acid and lithocholic acid) excretion in the feces. In conclusion, CLA supplementation and n-3 fatty acid could reduce tumor incidence by reducing eicosanoids and increasing antioxidant enzyme activities in colon and decreasing the excretion of deoxycholic acid and lithocholic acid in the feces. The data might suggest that CLA supplementation and n-3 DHA rich fish oil may modulate colon carcinogenesis.termediate level of endurance exercise training for 6 weeks did not influence concentrations of most of free amino acid in soleus muscle of rats collected at an overnight fasted and rested state. In contrast, isolucine and leucine concentrations in extensor digitorum longus muscle of exercise-trained rats were significantly lower than those for control animals. These results indicate that aerobic energy metabolism had not been efficiently conducted, and thereby the utilization of BCAA for energy substrate was enhanced in fast twitch oxidative glycolytic fibers of extensor digitorum longus muscle of rats followed exercise-training protocol for 6 weeks.

• BMB Reports
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• v.35 no.5
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• pp.494-497
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• 2002

The present study explored the short-term effects of dietary conjugated-linoleic acid (CLA) on liver lipid metabolism in starved/refed Otsuka Long Evans Tokushima Fatty (OLETF) rats. Male OLETF rats (12 weeks old) were starved for 24 hours, then refed for 48 hours with either a CLA diet [7.5% CLA and 7.5% Safflower oil (SAF)] or a SAF control diet (15% SAF). The results demonstrated a 30% reduction of hepatic triglyceride (TG) concentration in the CLA group when compared to the control group. Liver cholesterol concentration was also 26% lower in the CLA fed rats. The activity of mitochondrial carnitine palmitoyltransferase, the rate-limiting enzyme of fatty acid oxidation, was moderately elevated by 1.2-fold in the livers of the CLA group when compared to the control. In contrast, phosphatidate phosphohydrolase, the rate-limiting enzyme for TG synthesis, was found to be 20% lower in the livers of the CLA-fed rats. Therefore, dietary CLA evidently lowers liver lipid concentrations through a reduced TG synthesis and enhanced fatty acid oxidation in starved/refed OLETF rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.6
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• pp.752-760
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• 2008

Scale-up production of low-trans fat containing conjugated linoleic acid (CLA-TFO) was performed through lipase-catalyzed synthesis. Blend of fully hydrogenated soybean oil, olive oil containing conjugated linoleic acid and palm oil with 1:2:7 ratio was interesterified through Lipozyme RM IM in the 1 L-batch type reactor at $65^{\circ}C$ for 12 hrs, and the physicochemical and melting properties of CLA-TFO were compared with conventional (high trans fat) or commercial low-trans fat shortening. The trans fatty acids content in the conventional shortening (48.8 area%) was much higher than that of low-trans shortening (0.4 area%) and CLA-TFO (0.3 area%+CLA; 7.6 area%). Acid, saponification and iodine values of CLA-TFO were 0.4, 173.9 and 59.0, respectively. Their ${\alpha}$-, ${\gamma}$-tocopherol contents showed 4.7, 1.0 mg/100 g. Differences were observed in the solid fat contents (SFC), melting point of the conventional or low-trans fat and CLA-TFO. Each SFC of conventional, low-trans fat and CLA-TFO was 32.0, 29.3 and 30.4% with melting point of 38.5, 43.0 and $39.5^{\circ}C$ at $35^{\circ}C$, respectively. In texture profile analysis, hardness of conventional, low-trans fat and CLA-TFO was 111.7, 75.2 and 63.8 g.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.357-361
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• 2005

The bioconversion of linoleic acid (LA) to conjugated linoleic acid (CLA) was investigated to examine LA-adaptation of Bifidobacterium breve KCTC 3461 to additions of 1 to 5 mg/mL of LA overtime. To induce LA-adaptation, B. breve KCTC 3461 was treated with LA, according to three schemes. For LA-adapted B. breve the maximum concentration of CLA, $300\~350{\mu}g/mL$, was obtained in cys-MRS medium containing 1 mg/mL of LA. The CLA production significantly increased with increasing LA concentration, from 1 to 4 mg/mL, but the conversion of LA to CLA gradually decreased. The CLA production capability of B. breve, and its tolerance, improved significantly with LA-adaptation. The addition of LA (1 mg/mL) into the culture broth after 24 h of cultivation in a 100-mL media bottle was most effective at promoting CLA production. In a 2.5-L stirred-tank bioreactor, the observed conversion and productivity of $56.6\%\;and\;35.4{\mu}gmL^{-1}h^{-1}$, respectively, by LA-adapted B. breve were approximately 6.6 and 9.8 times higher than those of LA-unadapted B. breve.

• Journal of Animal Science and Technology
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• v.46 no.6
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• pp.967-974
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• 2004

The current study was undertaken to determine the effect of various conjugated linoleic acid (CLA) isomers on differentiation of pig preadipocyte during culture. Preadipocyte(stroma-vascular cell) was isolated from the backfat of newborn pigs and cultured to differentiate into mature fat cell. Different doses of CLA isomers were treated to the culture media at different times. Cell differentiation was determined by measuring the glycerol3-phosphate dehydrogenase activity of the cultured preadipocytes. Twenty and fifty $\mu$M of trans110_cis 12 isomer of CLA inhibited differentiation of pig preadipocyte whereas cis9-cis II isomer stimulated the differentiation. Both cis9-transII and trans9-trans11 isomers showed no effect. Effect of CLA isomer was more evident at the early stage of culture(day 0-8), than the late stage(day 8-14). These results suggest that each CLA isomer has different effect on pig preadipocyte differentiation.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1315-1328
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• 2004

Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with two conjugated double bonds. Of more than a dozen isomers of CLA found naturally in dairy and meat products from ruminants, c-9, t-11 and t-10, c-12 are the two isomers with known physiological importance, including anticarcinogenic, antidiabetic, antilipogenic, and antiatherosclerotic effects. Positive effects of CLA on immune function and bone modeling have also been reported. In spite of the compelling findings in tissue cultures and experimental animal models, its effect, dose, and mechanism of action vis-à-vis specific isomers remains speculative. Results obtained from animal models are inconclusive and conflicting at times in humans, where the research data is limited. It appears that there is a long way to go before CLA could be accepted unequivocally as having definite effects in any or all of these physiological states and how such effects actually occur in humans. The objective of this review is to critically examine the available literature on potential health benefits of CLA observed in cell culture, animal models, and human subjects, wherever possible and to a certain extent the mechanism of action associated with these biological activities.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.145-150
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• 2007

Conjugated linoleic acid (CLA) reduces fat deposition in several mammalian species. The proposed mechanisms for this effect are reduced preadipocyte proliferation and differentiation. The objective of this study was to investigate the inhibitory effects of diglyceride (DG), CLA, DG-CLA of proliferation and differentiation of 3T3-L1 preadipocytes. Cell viability was determined using WST-8 analysis and cell differentiation was determined by glycerol-3-phosphate dehydrogenase (GPDH) activity. Lipid accumulation in differentiating 3T3-L1 cells was measured by Oil red O staining. The proliferation of preconfluent 3T3-L1 cells by treatments of DG, CLA, and DG-CLA was reduced in a dose-dependent manner. CLA among them was the most effective in reduction of viable cells with increasing concentrations. Treatments of the DG, CLA, and DG-CLA at the concentration of $100{\cdot}\ddot{I}g/ml$ for 48h significantly inhibited differentiation of 3T3-L1 cells (p<0.05). In addition. cytoplasmic lipid accumulation during differentiation of the 3T3-L1 preadipocytes was also inhibited by treatments of the test solutions. DG-CLA was the most effective in the inhibition of differentiation and lipid accumulation in 3T3-L1 cells. These results indicate that the DG including CLA as fatty acids is more effective for anti-obesity than DG or CLA alone and that consumption of DG-CLA as a dietary oil may give a benefit for controlling overweight in humans.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1165-1170
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• 2003

A total of 250 laying hens were fed a diet containing 0, 1, 2.5 or 5% conjugated linoleic acid (CLA), and 5% Safflower seed oil (SSO) for 5 weeks, and eggs were collected by week to analyse lipid characteristics of egg yolk. Egg yolk from CLA-fed groups showed significant increase in CLA content with increased CLA in the diet. Dietary CLA also increased the ratio of saturated fatty acids and decreased unsaturated fatty acids in the egg yolk. The proportion of myristic, palmitic, stearic and CLA were increased, while those of oleic, linoleic, linolenic and arachidonic acid were decreased. The cholesterol content in egg yolk was significantly decreased by dietary CLA for 5 weeks feeding. After 7 days of feeding, 5% CLA-fed group showed the lowest cholesterol content in egg yolk. CLAfed groups showed significantly lower 2-thiobarbituric acid-reactive substances (TBARS) values compared to control and SSO-fed group after 14 days of storage. No significant differences in TBARS values among CLA-fed groups were observed at the 28 days of storage. Results suggested that lipid oxidation of egg yolk during cold storage could be inhibited by dietary CLA due not only to changes in fatty acid composition but also to the high concentration of CLA in egg yolk.