• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1568-1575
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• 2000

Growing pigs (N=25; 18 kg) were used to study effects of L-carnitine and protein intake on plasma carnitine, energy and carnitine balance, and carnitine biosynthesis. Corn-soybean meal basal diets containing low or high protein (13.6% or 18%) were formulated so that protein accretion would be limited by metabolizable energy (ME). Each basal diet was supplemented with 0 or 500 mg/kg L-carnitine and limit fed to pigs for 10 d in a balance trial. Final carnitine concentration was compared with weight/age matched pigs measured on d 0 to calculate carnitine retention rates. Supplementation of carnitine increased (p<0.01) plasma free carnitine (by 250%), short-chain (by 160%) and long-chain acyl-carnitine concentrations (by 80%) irrespective of blood sampling time (p<0.01). The proportion of long-chain carnitine esters decreased by 40% (p<0.01) by carnitine supplementation; whereas, the proportion of short-chain acyl-carnitine concentration was not changed (p>0.10). All criteria of energy balance were unaffected by L-carnitine (p>0.10). Total body carnitine retention was increased by 450% over unsupplemented controls (p<0.01). Carnitine biosynthesis rates in pigs fed diets without L-carnitine were estimated at 6.71 and $10.63{\mu}mol{\cdot}kg^{-1}{\cdot}d^{-1}$ in low protein and high protein groups, respectively. In supplemented pigs, L-carnitine absorption and degradation in the intestinal tract was estimated at 30-40% and 60-70% of L-carnitine intake, respectively. High protein feeding effect did not affected plasma carnitine concentrations, carnitine biosynthesis or carnitine retention (p>0.10). We conclude that endogenous carnitine biosynthesis may be adequate to maintain sufficient tissue levels during growth, but that supplemental dietary carnitine (at 500 ppm) sufficiently increased plasma acyl-carnitine and total body carnitine.

• Journal of Microbiology and Biotechnology
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• v.7 no.5
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• pp.318-322
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• 1997

In order to isolate a microorganism having preferential degradation of D-carnitine from DL-carnitine, a bacterium assimilating D-carnitine as a sole carbon and energy source was isolated from soil by enrichment culture and partially identified as Enterobacter sp. Also, a mutant having lessened L-carnitine decomposition rates was selected with nitrosoguanidine mutagenesis, which led to decrease the specific activities of carnitine dehydrogenase (7.6-fold) and ${\beta}$-hydroxybutyrate dehydrogenase (9.5-fold) as compared to the wild strain. Meanwhile, optimal culture conditions for optical resolution of DL-carnitine were investigated. Under optimal conditions, 3.53 g/l L-carnitine was obtained from 20 g/l DL-carnitine, which corresponded to 35.3% L-carnitine yield and 97.9% optical purity.

• The Korean Journal of Community Living Science
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• v.15 no.1
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• pp.77-83
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• 2004

The aim of this study was to investigate the effects of L-carnitine on the components of serum and liver and the effects on the anti-oxidant system. For this purpose, five experimental groups were setup. For fat source, perilla oil enough with unsaturated fatty acid and beeftallow enough with saturated fatty acid were supplemented together with L-carnitine to the rats. Five experimental groups kept eight Sprague-Dawley rats respectively, They were co group supplemented with basic diet or AIN-93, PO group supplemented with perilla oil, POC group supplemented with perilla oil and L-carnitine, BT group supplemented with beeftallow, and BTC group supplemented with beeftallow and L- carnitine. The results are. 1) Weight gain, food intake and FER were not different significantly among the experimental groups. 2) Significant difference was observed in serum total lipid(P<0.05), serum triglyceride(P<0.05), serum total cholesterol (P<0.05)and serum LDL cholesterol(P<0.05). Serum total lipid and serum triglyceride were significantly low in the groups supplemented with L-carnitine. Serum total cholesterol showed difference with the supplementation of L-carnitine in BTC only. LDL cholesterol showed no significant difference with the supplementation of L-carnatine, but total values of LDL-cholesterol were high in groups supplemented with beeftallow. 3) Total cholesterol in liver was low in POC group with the supplementation of L-carnitine however, there was no difference in BTC group with the supplementation of L-carnitine. In summary, dietary L-carnitine did not influence the weight gain, food intake and food efficiency ratio among the experimental groups, but had an effect of lowering the serum total lipid and triglyceride significantly in both groups which were supplemented with L-carnitine. The effect of lowering of sew total cholesterol with the supplementation of L-carnitine in beeftallow group(BTC) only. The effect of lowering of liver total cholesterol with the supplementation of L-carnitine in perilla oil group(POC) only.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.5
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• pp.799-805
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• 1999

This study was conducted to investigate the effects of L-carnitine with different levels of lysine on performance of pigs weaned at 21 days of age. A total of 120 pigs were allotted into a $3{\times}2$ factorial design with three different levels of lysine (1.40%, 1,60% and 1.80%) and two levels of L-carnitine (0 and 1,000 ppm). Each treatment had 4 replications with 5 pigs per replicate. Pigs of $22{\pm}1$ days (5.9 kg of body weight) were grouped into a completely randomized block design. Treatments were 1) 1.4-Crt; 1.40% of lysine with 1,000 ppm of L-carnitine, 2) 1.4-N; 1.40% of lysine without L-carnitine, 3) 1.6-Crt; 1.60% of lysine with 1,000 ppm of L-carnitine, 4) 1.6-N; 1.60% of lysine without L-carnitine, 5) 1.8-Crt; 1.80% of lysine with 1,000 ppm of L-carnitine and 6) 1.8-N; 1.80% of lysine without L-carnitine. Growth performance was optimized in pigs fed 1.6% lysine regardless of carnitine addition. For the first 7 days of the experimental period, the best ADG and F/G were found in pigs within the 1.6-Crt group. Carnitine significantly improved (p<0.05) ADG of pigs when the lysine level in the diet was 1.6%. Only in the third week carnitine had a significant influence on growth performance of pigs. A lysine-sparing effect of L-carnitine was not detected in this study. The 1.6-Crt group showed the best proximate nutrient digestibility, and the crude fat and gross energy digestibility were higher when the L-carnitine was added in the diet. Lysine level significantly affected the digestibilities of DM (p<0.001), GE (p<0.001), CP (p<0.01) and C.fat (p<0.05). Carnitine also significantly improved digestibility of nutrients. Lysine level as well as carnitine level affected the amino acids digestibility, however, in 1.8% lysine diet carnitine did not influence on amino acids digestibility. Plasma carnitine content was significant higher (p<0.05) in pigs fed L-carnitine. This indicates the increased biological availability of carnitine within the body. L-carnitine supplementation tended to improve feed utilization during the third week (p<0.10) and during the entire period (p=0.10). Lysine level significantly affected feed utilization of pigs during the third week and entire period (p<0.05). As pigs grew, the lysine requirement was reduced.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.15-21
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• 2009

Ergogenic aids are substances, devices, and practices that enhance an individual's energy use and production, and recovery from fatigue. L-carnitine increases enhance performance and aerobic capacity by stimulating lipid oxidation in muscle cells during long term exercise. L-carnitine is a well known and widely used ergogenic aid. In the present study, the effect of L-carnitine at concentrations of 100 nM, 1 μM, 10 μM, and 100 μM on the amplitude of field potential in rat cardiac muscle slices was measured using multi-channel extracellular recording (MED 64) system. In the present result, L-carnitine was shown to enhance field potential as a does-dependent manner. The increasing effect of the L-carnitine on field potential was not affected by application of the glibenclamide, an ATP-dependant K⁺ channel antagonist. The increasing effect of L-carnitine on field potential was suppressed by application of the diazoxide, an ATP-dependent K⁺ channel agonist. Present data show that L-carnitine potentiates field potentials by inhibition on ATP-dependant K⁺ channel in cardiac muscles. The enhancing effect of the L-carnitine on the field potential in cardiac muscles can be suggested as one of the underlying mechanism of ergogenic aid of the L-carnitine.

• KSBB Journal
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• v.14 no.2
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• pp.205-211
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• 1999

We investigated optimal conditions for the microbial transformation of $\gamma$-butyrobetaine into L-carnitine by using Achromobacter cycloclast ATCC 21921. When the cells were cultivated in the medium containing $\gamma$-butyrobetaine as the sole carbon source for both cell growth and L-carnitine production, the maximum L-carnitine production was 2.9 g/L and the conversion yield from $\gamma$-butyrobetaine to L-carnitine was as low as 30.9 mol%. In order to enhance the L-carnitine production and the conversion yield, various carbon sources were added to the $\gamma$-butyronetaine containing basal medium. In the medium supplemented with glycerol, L-carnitine production was as high as 4.6 g/L and the conversion yield was 88.2 mol%, showing a significant improvement in L-carnitine synthesis compared to those in the medium without glycerol. We also examined the additional effect of quaternary ammonium compounds such as betaine and choline, which are similar in structure to $\gamma$-butyrobetaine and L-carnitien. It was observed that in the presence of those quaternary ammonium compounds, both the L-carnitine production rate and the conversion yield increased. In addition, we found that cell growth was inhibited by a $\gamma$-butyrobetaine concentration of more than 3%, while L-carnitine production was efficient at the $\gamma$-butyrobetaine concentration of 2-3%. By cultivating the cells in the optimal medium containing glycerol and choline, we obtained an L-carnitine concentration of 7.2 g/L with the conversion yield of 98.7 mol% in 4 days.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.681-685
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• 2009

L-carnitine promotes mitochondrial ${\beta}$-oxidation of long chain fatty acids and their subsequent transport across the inner mitochondrial membrane. Although the role of L-carnitine in fatty acid metabolism has been extensively studied, its role in live performance and carcass responses of commercial broilers is less understood. The objective of this research was to determine if Lcarnitine fed at various levels in diets differing in CP and amino acids impacted on live performance and carcass characteristics of commercial broilers. Two floor pen experiments were conducted to assess the effect of dietary L-carnitine in grower diets. In Exp. 1, Ross${\times}$Hubbard Ultra Yield broilers were placed in 48 floor pens (12 birds/pen) and fed common diets to d 14. A two (0 or 50 ppm Lcarnitine) by three (173, 187, and 202 g/kg CP) factorial arrangement of treatments was employed from 15 to 35 d of age (8 replications/treatment). An interaction (p<0.05) in carcass yield indicated that increasing CP (187 g/kg) resulted in improved yield in the presence of L-carnitine. Increasing CP from 173 to 202 g/kg increased (p<0.05) BW gain and decreased (p<0.05) feed conversion and percentage abdominal fat. Feeding dietary L-carnitine increased back-half carcass yield which was attributable to an increase (p<0.05) in thigh, but not drumstick, yield relative to carcass. In Exp. 2, $Ross{\times}Ross$ 708 broilers were fed common diets until 29 d. From 30 to 42 d of age, birds were fed one of seven diets: i) 200 g/kg CP, 0 ppm L-carnitine; ii) 200 g/kg CP, 40 ppm L-carnitine; iii) 180 g/kg CP, 0 ppm L-carnitine; iv) 180 g/kg CP, 10 ppm L-carnitine; v) 180 g/kg CP, 20 ppm L-carnitine; vi) 180 g/kg CP, 30 ppm L-carnitine; and vii) 180 g/kg CP, 40 ppm L-carnitine (6 replications of 12 birds each). BW gain, feed conversion, mortality (30 to 42 d), and carcass traits (42 d) were measured on all birds by pen. There were no treatment differences (p<0.05). However, the addition of 40 ppm L-carnitine in the 200 g CP/kg diet increased (p = 0.06) thigh yields relative to BW in comparison to birds fed diets without L-carnitine, which was further confirmed via a contrast analysis (0 vs. 40 ppm L-carnitine in the 200 and 180 g CP/kg diets; p<0.05). These results indicated that dietary L-carnitine may heighten metabolism in dark meat of commercial broilers resulting in increased relative thigh tissue accretion without compromising breast accretion.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.303-308
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• 2019

L-carnitine is found in high levels in muscle tissues. It has been developed as a nutrient and dietary supplement, and also used as a therapeutic supplement in various diseases including type II diabetes, osteoporosis and metabolic neuropathies. However, it is not fully understood how it affects cellular mechanisms in colorectal cancer. Therefore, we attempted to determine the effect of L-carnitine in HCT116 human colorectal cancer cells. First, the HCT116 cells were exposed to L-carnitine for 24 hours at 0-40 mM, and then analyzed for cellular proliferation, oxidative stress and related mechanisms. In a MTT assay, L-carnitine inhibited cellular proliferation and induced reactive oxygen species (ROS) in HCT116 by DCF-DA analysis. To analyze the mechanism of L-carnitine in colorectal cancer cells, we performed a western blot analysis for pERK1/2 and pp38 MAP kinase. The western blot showed that L-carnitine significantly increased protein levels of pERK1/2 and pp38 compared with control. Taken together, we found that L-carnitine has anti-proliferative function via increased ROS and activation of ERK1/2 and p38 pathway in HCT116. These findings suggest that L-carnitine may have an anti-proliferative role on colorectal cancer.

• Clinical and Experimental Pediatrics
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• v.45 no.9
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• pp.1075-1082
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• 2002

Purpose : Obesity is known to be associated with hypertension, dyslipidemia, and fatty liver and is thought to be associated with increased levels of free fatty acids. One of the strategies for decreasing free fatty acid levels is stimulation of hepatic lipid oxidation with L-carnitine. Carnitine is an essential cofactor for transport of long-chain fatty acid into mitochondria for oxidation. This study was designed to evaluate the changes of serum fatty acids and carnitine levels after exogenous injection of L-carnitine. Methods : Sprague Dawley rats were divided into two groups. Group A was control. Group B was given intraperitoneal injection with L-carnitine(200 mg/kg) daily for two weeks. Serum lipid (total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol) and fatty acid levels were analyzed on the first day of the first and second weeks after injection of L-carnitine. Total, free, and acyl carnitine levels also were performed by a enzymatic cycling techniques at the same day intervals. Results : There was no significant difference between the two groups in total cholesterol, HDL-cholesterol, LDL-cholesterol levels before and after the administration of L-carnitine. But triglyceride levels were significantly decreased at the first week in group B compared with group A. Among free fatty acids, linoleic acid showed significant decrement(A group : $131.3{\pm}31.3mg/dL$ vs B group : $90.0{\pm}7.0mg/dL$) at the first week. Total, free, and acyl carnitine levels showed significant increments at all days intervals, but only free carnitine showed significant increments according to cumulative doses of carnitine. Conclusion : Plasma linoleic acid, a long-chain fatty acid, showed significant decrement after administration of L-carnitine in the first week. This may suggest that L-carnitine can be used as an antilipidemic agent for obese patients. A prospective study will investigate obese children in the future.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.4
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• pp.295-300
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• 2001

Objective : To assess the effects of progesterone and acetyl-L-carnitine used after treated with Isolate�� gradient before semen cryopreservation-thawing on sperm parameters and membrane integrity. Material and Methods : From April 2001 to July 2001, ten normal male partner of couples who were visited in vitro fertilization (IVF) clinics. the semens were treated with $Isolate^{(R)}$ gradient before cryopreservation, spermatozoa was incubated with progesterone (1, 5 and $10{\mu}M$), acetyl-L-carnitine (2.5, 5 and $10{\mu}M$), or both (progesterone, $1{\mu}M$; and acetyl-L-carnitine, $5{\mu}M$) for 30 min. Results: There were no differences in sperm parameters and vital stain among isolate only treated group, progesterone (1, 5 and $10{\mu}M$), acetyl-L-carnitine (2.5, 5 and $10{\mu}M$) and both (progesterone, $1{\mu}M$; and acetyl-L-carnitine, $5{\mu}M$). But, in high concentration of acetyl-L-carnitine ($10{\mu}M$) treated group, sperm parameters and vital stain were decreased. The statistical method was used ANOVA (Kruskal-Wallis test) and p value was <0.01. Conclusions : Neither progesterone nor acetyl-L-carnitine show to be protective effect on the cryodamage assessed by sperm parameters and vital stain (eosin-Y stain) in normal sperm. High concentration of acetyl-L-carnitine ($10{\mu}M$), however, was harmful effect on cryoprevention.