Dietary Α-lipoic Acid Research Articles

Evaluation of dietary α-lipoic acid supplementation on the growth performance and physiological status of striped catfish Pangasianodon hypophthalmus

This study aimed to evaluate the dietary supplementation of α-lipoic acid (ALA) on the growth performance, antioxidative capacity, and protein-sparring effect of striped catfish (Pangasianodon hypophthalmus) fingerling. The striped catfish (individual weight of 1.4 ± 0.0 g) were stocked in 25 cages at 2x1x1.5 m size in a 200-m pond at 50 fish. Fish were fed formulated diets with ALA supplementation, namely: diet A (27% protein: 390 kcal), diet B (27% protein: 390 kcal +ALA 8 g/kg), diet C (27% protein: 400 kcal), diet D (27% protein: 400 kcal +ALA 8 g/kg), and diet E (30% protein: 390 kcal). Feeding was performed until apparent satiation for 60 days. The ALA supplementation significantly produced higher final individual weight, specific growth rate, and protein efficiency ratio, followed by a lower feed conversion ratio on the 27:390+ALA diet treatment (P<0.05) than other diet treatments. The highest liver performance based on superoxide dismutase enzyme activity and glycogen contents was obtained from the 27:390+ALA diet treatment. The malondialdehyde, triglycerides, and lipid accumulation in the liver on the 27:390+ALA diet treatment were lower than other diet treatments (P<0.05). Therefore, the best growth performance and physiological status in striped catfish was obtained from 27:390+ALA diet treatment.

Dietary α-lipoic acid supplementation improves postmortem color stability of the lamb muscles through changing muscle fiber types and antioxidative status

This study investigated the effect of dietary α-lipoic acid (600 mg/kg) supplementation on the postmortem color stability of the biceps femoris from lambs. The results showed that dietary α-lipoic acid supplementation increased a* and decreased b* and metmyoglobin (MMb) percentage of the biceps femoris with the time of storage (P < 0.05). The content of malondialdehyde (MDA) reduced with the time of storage after treatment with α-lipoic acid (P < 0.05). α-lipoic acid increased the myoglobin (Mb) content, and myosin heavy chain I (MyHC I) gene expression but decreased glycogen content, lactate dehydrogenase (LDH) activity, and MyHC IIb gene expression (P < 0.05). The T-AOC value, catalase (CAT) activity, and expression of SOD and CAT gene expression increased after α-lipoic acid treatment (P < 0.05). Therefore, dietary α-lipoic acid supplementation improved the meat color by regulating muscle fiber types and inhibited glycolysis. Moreover, α-lipoic acid maintained meat color stability by effectively inhibiting muscle oxidation via enhancing the antioxidant capacity

Dietary α-lipoic acid alleviates deltamethrin-induced immunosuppression and oxidative stress in northern snakehead (Channa argus) via Nrf2/NF-κB signaling pathway

The goal of the study was to determine the ameliorative effects of dietary alpha-lipoic acid (α-LA) on deltamethrin (DEL)-induced immunosuppression and oxidative stress in northern snakehead (Channa argus). The northern snakeheads (15.38 ± 0.09 g) were exposed to DEL (0.242 μg/L) and fed with diets supplemented α-LA at 300, 600, and 900 mg/kg. After the 28-day exposure test, we obtained the following results: i) α-LA alleviates DEL-induced liver injury by reversing the increase of the serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and liver cytochrome P450 enzymes (Cytochrome P450 (cyp)1a and cyp1b) expression levels. ii) α-LA can reverse the DEL-induced reduction of serum complement 4 (C4), C3, immunoglobulin M (IgM), and lysozyme (LYS) levels and the increase of liver and intestine nuclear factor kappa B (nf-κb) p65, tumor necrosis factor (tnf)-α, interleukin (il)-1β, il-8, and il-6 gene expressions, while il-10 expression levels showed the opposite result. iii) α-LA reversed the reduction of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px) levels in the liver and intestine induced by DEL, while malondialdehyde (MDA) showed the opposite result. iv) α-LA reversed the reduction of Cu/Zn sod, nuclear factor erythroid 2-related factor 2 (nrf2), NAD (P)H: quinone oxidoreductase (nqo)1, and heme oxygenase (ho)-1 antioxidant gene expression levels in the liver and intestine induced by DEL. Therefore, our study indicated that optimal α-LA (600 mg/kg) could attenuate DEL-induced toxicity (including liver damage, immunotoxicity, and oxidative stress) in northern snakehead via Nrf2/NF-κB signaling pathway. This is the first research that explores the alleviated effects of α-LA on DEL-induced toxicity damage in fish. This study provides a positive measure to reduce the toxicity damage caused by DEL to aquatic animals, and provides a theoretical basis for exploring the regulation mechanism of α-LA in toxic substances.

Dietary α-lipoic acid can alleviate the bioaccumulation, oxidative stress, cell apoptosis, and inflammation induced by lead (Pb) in Channa argus

This study aims to evaluate the effects of dietary α-lipoic acid (α-LA) on bioaccumulation, oxidative stress, apoptosis, and inflammation in Channa argus after 28 d of lead (Pb) exposure. A total of 300 fish were divided into five groups: the first group was the control group and the other four groups were exposed to waterborne Pb (800 ppb) and fed α-LA diets supplemented with 0, 300, 600, and 900 mg/kg. The results demonstrated that dietary α-LA effectively reduced the Pb accumulation in the liver, kidney, gill, intestine, and muscle of C. argus after exposure to Pb. Meanwhile, dietary α-LA reversed alterations in the biochemical parameters (Alanine aminotransferase (ALT), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), blood urea nitrogen (BUN), cortisol (COR), and creatinine (CRE)) and immunity parameters (myeloperoxidase (MPO), complement 3 (C3), lysozyme (LYS), complement 4 (C4), C-reactive protein (CRP), and immunoglobulin M (IgM)) in the serum of fish caused by Pb. Pb-induced reduction of antioxidant enzyme activities (Catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px)) was inhibited by dietary α-LA. And malondialdehyde (MDA) and protein carbonyl (PC) content exhibited an opposite trend. Meanwhile, dietary supplemented with α-LA was found to relieve Pb-induced oxidative stress by downregulating Keap1 mRNA expression levels and upregulating the expression levels of CAT, nuclear factor erythroid 2-related factor 2 (Nrf2), GSH-Px, and Cu/Zn SOD. Furthermore, α-LA supplementation reversed Pb-induced upregulation of pro-inflammatory genes (interleukin (IL)-6, IL-1β, tumor necrosis factor α (TNF-α), and nuclear factor kappa B (NF-κB)), Pro-apoptotic genes (Bcl-2-associated X (Bax), caspase (Cas)-3, and tumor protein p53 (p53)) and Hsp70, and downregulation of anti-inflammatory genes (IL-10, inhibitor of κBα (IκBα), and transforming growth factor β (TGF-β)) and anti-apoptosis gene (B-cell lymphoma-2 (Bcl-2)). Overall, dietary α-LA supplementation could enhance the innate immunity and antioxidant capacity of fish, attenuating the Pb accumulation, and cell apoptosis after being exposed to Pb. Furthermore, dietary α-LA could relieve Pb-induced inflammatory response and oxidative stress of fish via regulating NF-κB and Nrf2 signaling, respectively.

Dietary α-lipoic acid requirement and its effects on antioxidant status, carbohydrate metabolism, and intestinal microflora in oriental river prawn Macrobrachium nipponense (De Haan)

Alpha lipoic acid (α-LA) is not only a natural antioxidant, but also a key cofactor for the enzymes pyruvate dehydrogenase and α-ketoglutarate dehydrogenase. The purpose of this study was to investigate the effects of dietary α-lipoic acid on the growth, antioxidant status, carbohydrate metabolism, and intestinal microflora of prawn, Macrobrachium nipponense. A total of 1250 juvenile M. nipponense with an average body weight of 0.050 ± 0.003 g were randomly divided into five groups with three replicates (50 prawns per tank) for an 8-week feeding trial. The groups were fed with basal semi-purified diets containing α-lipoic acid at five different concentrations: 0 mg/kg (LA1), 500 mg/kg (LA2), 1000 mg/kg (LA3), 2000 mg/kg (LA4) and 4000 mg/kg (LA5). The results showed that the weight gain (WG), specific growth rate (SGR) and the survival rate were significantly lower in LA5 than in other groups. Dietary α-lipoic acid at a concentration below 2000 mg/kg (LA4) significantly reduced the malondialdehyde (MDA) content and increased the glutathione (GSH) content in the hepatopancreas of M. nipponense, and significantly increased the activities of glutathione reductase (GR), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD). However, the MDA content in the hepatopancreas was higher in LA5 than in LA1. The prawns in the LA3 group showed the highest activities of isocitrate dehydrogenase (ICDH) and key enzymes in glycolysis (pyruvate kinase, PK; 6-phosphofructokinase, PFK; Hexokinase, HK), but lower activity of lactate dehydrogenase (LDH) compared with those in LA1 and LA2. Analyses of gut microflora at the operational taxonomic unit (OTU) level indicated that abundance (Chao index) and diversity (Simpson index) were lower in LA5 than in LA1 and LA3. The Shannon index's index was highest in LA5. The intestinal flora of M. nipponense comprised five main phyla and five main bacteria. The proportions of Proteobacteria and Citrobacter were higher in LA3 and LA5 than in LA1. The proportions of Actinobacteria, Bacteroidetes Aeromonas, Tyzzerella_3 and Mycobacterium were significantly higher in LA5 than in LA3 and LA1. In summary, dietary α-lipoic acid at an appropriate level (<2000 mg/kg) can improve the antioxidant capacity and carbohydrate metabolism of M. nipponense and modulate its intestinal microbiota without reducing growth performance. Excessive α-lipoic acid (4000 mg/kg) negatively affected the growth performance and antioxidant activity of M. nipponense. Calculations based on WG and SGR indicate that the optimal addition amount of α-lipoic acid for juvenile M. nipponense is 1354.8 mg/kg and 1329.92 mg/kg, respectively.

Dietary α-lipoic acid supplementation to improve growth, blood chemistry, and liver antioxidant status of African catfish Clarias gariepinus

Dietary α-lipoic acid supplementation to improve growth, blood chemistry, and liver antioxidant status of African catfish Clarias gariepinus

Systemic effect of dietary lipid levels and α-lipoic acid supplementation on nutritional metabolism in zebrafish (Danio rerio): focusing on the transcriptional level.

Considering the excessive lipid accumulation status caused by the increased dietary lipid intake in farmed fish, this study aimed to investigate the systemic effect of dietary lipid levels and α-lipoic acid supplementation on nutritional metabolism in zebrafish. A total of 540 male zebrafish (0.17g) were fed with normal (CT) and high lipid level (HL) diets for 6weeks, then fed on 1000mg/kg α-lipoic acid supplementation diets for the second 6weeks. HL diets did not affect whole fish protein content, but increased ASNS expression (P <0.05). Dietary α-lipoic acid increased whole fish protein content, and decreased the expressions of protein catabolism-related genes in muscle of high lipid level groups (P <0.05). Furthermore, HL diets increased the whole fish lipid content and the expressions of gluconeogenesis and lipogenesis-related genes (P <0.05), and α-lipoic acid counteracted these effects and decreased the whole fish triglyceride and cholesterol contents and expressions of lipogenesis-related genes, with the enhanced expressions of lipolytic genes, especially in high lipid groups (P <0.05). HL diets did not affect hepatocyte mitochondrial quantity or the mRNA expressions of mitochondrial biogenesis and electron transport chain-related genes; they were significantly increased by dietary α-lipoic acid (P <0.05). These results indicated that high dietary lipid promotes lipid accumulation, while α-lipoic acid increases protein content in association of enhanced lipid catabolism. Thus, dietary α-lipoic acid supplementation could reduce lipid accumulation under high lipid, which provides a promising new approach in solving the problem of lipid accumulation in farmed fish.

The comparisons in protective mechanisms and efficiencies among dietary α-lipoic acid, β-glucan and l-carnitine on Nile tilapia infected by Aeromonas hydrophila

Dietary α-lipoic acid (LA), β-glucan (Gluc) and l-carnitine (L-Ca) are commonly used additives to promote fish growth and stress resistance in aquaculture production. However their mechanisms and efficiencies in helping fish to resist diseases have not been compared before. In this study, we fed Nile tilapia (Oreochromis niloticus) with diets containing appropriate doses of LA, Gluc and L-Ca for five weeks and further intraperitoneally injected the fish with Aeromonas hydrophila. After dietary treatment, none of the additives affected the fish growth, but dietary Gluc and L-Ca reduced protein and lipid body contents in fish, respectively. After A. hydrophila challenge, all fish treated with the three dietary additives showed higher survival rate, but those fed on dietary L-Ca had lower survival than those fed on LA and Gluc diets, indicating high protection efficiency of LA and Gluc. The protective mechanisms of the three feed additives were quite different under A. hydrophila infection. Dietary LA induced higher total antioxidant capacity and higher mRNA expression of anti-oxidative genes than other additives in liver and also activated partly the immune function in serum and spleen. Gluc largely increased the immune function by activating the immunity enzymes in serum, inducing inflammation in liver and increasing the expression of immune genes in spleen and head kidney. Gluc also increased partly the antioxidant capacity in serum and liver and lipid catabolism in liver. L-Ca largely increased lipid catabolism in liver while it increased partly the antioxidant capacities in serum and liver. Taken together, these results indicate that, dietary LA, Gluc and L-Ca have various protective mechanisms and differ in their efficiencies on resisting A. hydrophila infection in Nile tilapia.

Protective effects of dietary α-lipoic acid on abalone Haliotis discus hannai against the oxidative damage under waterborne cadmium stress

Protective effects of dietary α-lipoic acid on abalone <i>Haliotis discus hannai</i> against the oxidative damage under waterborne cadmium stress

Effects of dietary α-lipoic acid on carcass characteristics, antioxidant capability and meat quality in Hainan black goats

The effects of α-lipoic acid (LA) on the carcase characteristics, antioxidant capability and meat quality of Hainan black goat were investigated in the present study. Thirty goats (10.71 ± 0.42 kg) were randomly assigned with three levels of LA in the concentration diet (0, 300, 600 mg/kg). The goats fed for 70 days. The results showed that goats fed the diet containing 600 mg/kg LA had a significantly (p < .05) higher ADG and better feed conversion rate (FCR) compared with goats offered the basal diet without LA. There were no differences in carcase characteristics among the three treatments. For antioxidant enzymes, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) and catalase (CAT) in serum significantly increased (p < .05) in goats fed with 600 mg/kg LA at day 70. The concentration of malondiadehhyde (MDA) was significantly lower (p < .05) in serum of goats that received 600 mg/kg LA than in the goats fed diet without LA. Addition level of LA had no significant impact on pH and intramuscular fat (IMF) of longissimus dorsi muscle tissue (LM) and semimembranosus muscle tissue (SM) in the goats (p > .05). However, increasing additional LA in the diet caused a decrease on drip loss and WBSF (p < .05). Treatment of goats with 600 mg/kg of LA has the lowest drip loss and WBSF. These results indicate that diet supplementation with LA may enhance antioxidant capability, improved the growth performance and meat quality in Hainan black goats.

Various levels and forms of dietary α-lipoic acid in broiler chickens: Impact on blood biochemistry, stress response, liver enzymes, and antibody titers

The present experiment was conducted to evaluate the impact of various levels and forms of α-lipoic acid (ALA) on blood biochemistry, immune and stress response, and antibody titers in broiler chickens. The four levels (7.5, 15, 75, and 150 ppm) and 2 sources (powder, P-ALA and encapsulated, E-ALA) of ALA along with negative (C−) and positive control (C+; contains antibiotics) diets consisted of 10 dietary treatments, and these treatments were allocated to 1,200 1-d-old chicks and were replicated 12 times with 10 birds per replicate. Among the blood biochemistry parameters, creatinine levels were almost 3 times lower in E-ALA-supplemented diets compared to the C− diet (0.09 vs. 0.25 mg/dL; P < 0.0001). Neither level nor source of ALA affected blood urea nitrogen (BUN), total protein (TP), albumin, globulin, or albumin to globulin ratio (AGR). The supplemented diets decreased serum levels of the liver enzymes aspartate-aminotransferase (AST; P < 0.006) and alanine-aminotransferase (ALT; P < 0.0003). The Newcastle disease virus (NDV) antibody response in supplemented groups was poor at day zero (P < 0.0001) but increased by d 14 (P < 0.03). Birds did not respond to infectious bronchitis virus (IBV) vaccination at any observed stage (P > 0.05). The concentration of cortisol was reduced in chickens fed ALA-supplemented diets as compared to the C− diet (P < 0.001). Results suggest that ALA-supplemented diets ameliorated blood biochemistry profiles and immune responses and reduced stress in broiler chickens. The encapsulated form of ALA was more effective than the powder form.

Effects of dietary α-lipoic acid, acetyl-l-carnitine, and sex on antioxidative ability, energy, and lipid metabolism in broilers

An experiment was conducted to evaluate the effects of dietary α-lipoic acid (LA), acetyl-l-carnitine (ALC), and sex on antioxidative ability, energy, and lipid metabolism in broilers. A total of 972 one-day-old broilers with equal sex were randomly assigned in a 3 × 3 × 2 factorial design using 3 LA, 3 ALC levels, and 2 sexes (6 replications, 9 birds/replication). The LA and ALC levels were 0, 50, and 100 mg/kg, respectively. Results showed that increased LA or ALC resulted in increased total antioxidant capacity and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and decreased levels of malondialdehyde in serum and liver of birds (P < 0.05). In addition, with increasing addition of LA or ALC, an increased (P < 0.01) level of insulin (Ins), as well as decreased (P < 0.05) levels of glucose and glucagon (Glu), were observed in serum of broilers. Total cholesterol and triglyceride (TG) levels decreased (P < 0.05) and nonesterified fatty acid, lipoprotein lipase, and lipase levels increased (P < 0.05) in serum with increased administration of LA or ALC. Moreover, a significant (P < 0.05) interaction of LA × ALC was observed for serum and liver SOD, serum GSH-Px, glucose, and TG levels. Birds fed diets containing 50 mg/kg of LA and 50 mg/kg of ALC had higher serum and liver SOD activities and lower serum glucose and TG levels than those fed diets containing 100 mg/kg of LA or ALC alone. The main effect of sex and all interactions among main effects (except LA × ALC) were not significant (P > 0.05) for all of the above parameters. Overall, the present data indicate that LA or ALC supplementation, or both, at low levels (50 or 100 mg/kg) improved antioxidative ability, energy metabolism, and lipid metabolism in broilers, and synergistic effects by the combined supplementation of LA and ALC were indicated by serum and liver SOD activities and serum glucose and TG levels.

Abstract 1588: Detection in vivo of a novel endogenous etheno DNA adduct derived from arachidonic acid and the effects of antioxidants on its formation

Abstract Previous studies showed that the 7-(1′,2′-dihydroxyheptyl) substituted etheno DNA adducts are products from reactions with epoxide of (E)-4-hydroxy-2-nonenal (HNE), an oxidation product of n-6 polyunsaturated fatty acids (PUFAs). In this work, we report the detection of 7-(1′,2′-dihydroxyheptyl)-1,N6-ethenodeoxyadenosine (DHHedA) in rodent and human tissues by two independent methods: a 32P-postlabeling/HPLC method and an isotope dilution liquid chromatography electrospray ionization tandem mass spectrometry method (ID-LC-ESI-MS/MS). This study demonstrated for the first time that DHHedA is a background DNA lesion in vivo. We showed that DHHedA can be formed upon incubation of arachidonic acid (AA) with deoxyadenosine (dA), supporting the notion that n-6 PUFAs are the endogenous source of DHHedA formation. Because the cyclic adducts are derived from the oxidation of PUFAs, we subsequently examined the effects of antioxidants, α-lipoic acid, polyphenon E and vitamin E on the formation of DHHedA and γ-hydroxy-1,N2-propanodeoxyguanosine (γ-OHPdG), a widely studied acrolein-derived cyclic adduct arisen from oxidized n-3 and n-6 PUFAs, in the livers of Long Evans Cinnamon (LEC) rats. LEC rats are inflicted with elevated lipid peroxidation and prone to the development of hepatocellular carcinomas. The results showed that while the survival of LEC rats was increased significantly by dietary α-lipoic acid, none of the antioxidants inhibited the formation of DHHedA and only polyphenon E treatment decreased the formation of γ-OHPdG. In contrast, vitamin E caused an increase in the formation of both γ-OHPdG and DHHedA in the livers of LEC rats. This work was supported by the NCI grant: RO1-CA-134892. Citation Format: Ying Fu, Marcin Dyba, Jishen Pan, Casey Schultz, Peiying Yang, Dhimant Desai, Shantu Amin, Fung-Lung Chung. Detection in vivo of a novel endogenous etheno DNA adduct derived from arachidonic acid and the effects of antioxidants on its formation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1588. doi:10.1158/1538-7445.AM2014-1588

Effect of dietary α-lipoic acid on the mRNA expression of genes involved in drug metabolism and antioxidation system in rat liver.

In the present study, the mRNA levels of hepatic proteins involved in the drug metabolism of rats fed α-lipoic acid were evaluated by DNA microarray and real-time PCR analyses. Experimental diets containing 0, 0·1, 0·25 and 0·5 % (w/w) α-lipoic acid were fed to four groups of rats consisting of seven animals each for 21 d. DNA microarray analysis revealed that the diet containing 0·5 % α-lipoic acid significantly (P< 0·05) increased the mRNA levels of various phase I drug-metabolising enzymes up to 15-fold and phase II enzymes up to 52-fold in an isoenzyme-specific manner. α-Lipoic acid also up-regulated the mRNA levels of some members of the ATP-binding cassette transporter superfamily, presumed to be involved in the exportation of xenobiotics, up to 6·6-fold. In addition, we observed that α-lipoic acid increased the mRNA levels of many proteins involved in antioxidation, such as members of the thiol redox system (up to 5·5-fold), metallothioneins (up to 12-fold) and haeme oxygenase 1 (1·5-fold). These results were confirmed using real-time PCR analysis, and α-lipoic acid dose dependently increased the mRNA levels of various proteins involved in drug metabolism and antioxidation. Consistent with these observations, α-lipoic acid dose dependently increased the hepatic concentration of glutathione and the activities of glutathione reductase and glutathione transferase measured using 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrates, but decreased the hepatic and serum concentrations of malondialdehyde. In conclusion, the present study unequivocally demonstrated that α-lipoic acid increases the mRNA expression of proteins involved in drug metabolism and antioxidation in the liver.

The effect of dietary α-lipoic acid, betaine, l-carnitine, and swimming on the obesity of mice induced by a high-fat diet.

We evaluate the effect of supplementation, at 300 mg kg(-1) body weight (BW), with the antioxidants α-lipoic acid (AL), betaine (BT), l-carnitine (LC), and the combination of these and exercise on obesity induced by a 9 week high-fat diet (HFD) in mice. Healthy 5 week-old male C57BL/6J mice were divided into 9 groups: (1) CON, control group fed with a commercial mice chow containing 10% crude fat; (2) HFD, high fat diet group fed with a commercial mice chow containing 60% crude fat; (3) HFD-AL, HFD group fed with AL; (4) HFD-BT, HFD group fed with BT; (5) HFD-LC, HFD group fed with LC; (6) HFD-SW, HFD with swimming as an exercise; (7) HFD-SWAL, HFD-AL with swimming; (8) HFD-SWBT, HFD-BT with swimming, and (9) HFD-SWLC, HFD-LC with swimming. The BW of mice with LC and swimming reduced the increase of BW after 9 weeks. Relative adipose tissue weights were reduced by the combinations of antioxidant supplementation and swimming. Levels of serum glucose and leptin were reduced in the HFD-SWLC group when compared with the HFD group. Serum triglyceride and total cholesterol and the size of adipose were also decreased in the HFD-LC and HFD-SWLC groups. These results show that LC at a dose of 300 mg kg(-1) BW was the most effective for reducing fat accumulation in mice with HFD for 9 weeks. In addition, exercise should be given in combination to enhance the BW reduction and serum lipid level.

Dietary α-Lipoic Acid Prevents UVB-Induced Corneal and Conjunctival Degeneration Through Multiple Effects

This study investigated the effects of dietary α-lipoic acid (α-LA) against ultraviolet B (UVB)-induced corneal and conjunctival degeneration in a mouse model. Female CBA mice were randomly divided into five study groups, including blank control, UVB without α-LA, and UVB with dietary α-LA at 1, 10, and 100 mg/kg body weight. Following UVB exposure, corneal surfaces were assessed along with immunohistochemistry for nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), malondialdehyde (MDA) accumulation, and P63⁺ basal cell distribution. Matrix metalloproteinase (MMP)-2 and MMP-9 activities were determined by gelatin zymography. ELISA assay was performed to confirm the findings of immunohistochemistry for NF-κB, COX-2, and MDA, along with the levels of TNF-α and IL-6. Tear production and goblet cell density were determined after tear strip assay and periodic acid Schiff staining, respectively. The results showed that UVB irradiation caused corneal surface damage, polymorphonuclear leukocyte infiltration, and loss of P63⁺ basal cells. Dietary α-LA ameliorated the UVB-induced corneal damage while simultaneously reducing MDA accumulation and maintaining P63⁺ basal cell survival. NF-κB-p65, COX-2, TNF-α, IL-6, and MMP-9 activity were all reduced by dietary α-LA. In addition, α-LA helped to reverse aqueous tear reduction, conjunctival squamous epithelium metaplasia, and goblet cell loss after UVB exposure. Dietary α-LA can prevent UVB-induced corneal damage and can be used as a prophylactic agent prior to excessive UVB exposure.

Selective deposition of dietary α-Lipoic acid in mitochondrial fraction and its synergistic effect with α-Tocoperhol acetate on broiler meat oxidative stability

The use of bioactive antioxidants in feed of broiler to mitigate reactive oxygen species (ROS) in biological systems is one of promising nutritional strategies. The aim of present study was to alleviate ROS production in mitochondrial fraction (MF) of meat by supplemented dietary antioxidant in feed of broiler. For this purpose, mitochondria specific antioxidant: α-lipoic acid (25 mg, 75 mg and 150 mg) with or without combination of α-tocopherol acetate (200 mg) used in normal and palm olein oxidized oil (4%) supplemented feed. One hundred and eighty one day old broiler birds were randomly divided into six treatments and provided the mentioned feed from third week. Feed intake, feed conversion ratio (FCR) remained statistically same in all groups while body weight decreased in supplemented groups accordingly at the end of study. The broiler meat MF antioxidant potential was significantly improved by feeding supplemented feed estimated as 1,1-di phenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, 2,2-azinobis-(3- ethylbenzothiazoline-6-sulphonic acid) (ABTS+) and thiobarbituric acid reactive substances (TBARS). The maximum antioxidant activity was depicted in group fed on 150 mg/kg α-lipoic acid (ALA) and 200 mg/kg α-tocopherol acetate (ATA) (T4) in both breast and leg MF. Moreover, TBARS were higher in leg as compared to breast MF. Although, oxidized oil containing feed reduced the growth, lipid stability and antioxidant potential of MF whilst these traits were improved by receiving feed containing ALA and ATA. ALA and ATA showed higher deposition in T4 group while least in group received oxidized oil containing feed (T5). Positive correlation exists between DPPH free radical scavenging activity and the ABTS + reducing activity. In conclusion, ALA and ATA supplementation in feed had positive effect on antioxidant status of MF that consequently diminished the oxidative stress in polyunsaturated fatty acid enriched meat.

Dietary alpha lipoic Acid improves body composition, meat quality and decreases collagen content in muscle of broiler chickens.

A total of 192 broiler chicks were used to evaluate the influence of dietary α-lipoic acid (ALA) on growth performance, carcass characteristics and meat quality of broiler chickens with the purpose of developing a strategy to prevent the occurrence of pale, soft, and exudative (PSE) meat and to improve the meat quality of broilers. At 22 d of age, birds were allocated to 4 ALA treatments (0, 400, 800, and 1200 ppm). The results showed that dietary ALA significantly decreased average feed intake (AFI), average daily gain (ADG), final live body weight (BW) and carcass weight (p<0.05), while no difference in feed conversion ratio (FCR) was detected among chickens fed with and without ALA. Abdominal fat weight significantly decreased (p<0.05) for broilers fed 800 and 1200 ppm ALA. However when calculated as the percentage of carcass weight there was no significant difference between control and ALA treatments. Meat quality measurements showed that dietary ALA regulated postmortem glycolysis and improved meat quality as evidenced by increased muscle pH and decreased drip loss of meat (p<0.05). Although ALA did not change the tenderness of meat as indicated by meat shear force, dietary ALA decreased collagen content and mRNA expression of COL3A1 gene (p<0.05). In conclusion, the results indicate that dietary ALA may contribute to the improvement of meat quality in broilers.

Effects of dietary α-lipoic acid enantiomers on hepatic fatty acid metabolism in rats

Effects of dietary α-lipoic acid enantiomers on hepatic and serum lipid concentrations and the activity and mRNA levels of enzymes involved in hepatic fatty acid metabolism were examined in rats. Rats were fed experimental diets containing 0 or 2.5g/kg of α-lipoic acid enantiomers (a racemic mixture of R/S-, S- or R-α-lipoic acid) for 21days. Various α-lipoic acid preparations decreased serum and liver concentrations of triacylglycerol, and also lowered serum concentrations of cholesterol and phospholipid and the concentration of cholesterol in the liver. α-Lipoic acid decreased the activity and mRNA levels of various hepatic lipogenic enzymes and also decreased the activities of carnitine acyltransferase and 3-ketoacyl-CoA thiolase and mRNA levels of carnitine palmitoyltransferase 1a involved in fatty acid oxidation in the liver; however, R- and S-enantiomers of α-lipoic acid as well as well as a racemic mixture of R/S-α-lipoic acid were indistinguishable in altering these indices for lipid metabolism.

Combined effect of sesamin and α-lipoic acid on hepatic fatty acid metabolism in rats

Dietary sesamin (1:1 mixture of sesamin and episesamin) decreases fatty acid synthesis but increases fatty acid oxidation in rat liver. Dietary α-lipoic acid lowers hepatic fatty acid synthesis. These changes can account for the serum lipid-lowering effect of sesamin and α-lipoic acid. It is expected that the combination of these compounds in the diet potentially ameliorates lipid metabolism more than the individual compounds. We therefore studied the combined effect of sesamin and α-lipoic acid on lipid metabolism in rats. Male Sprague-Dawley rats were fed diets supplemented with 0 or 2 g/kg sesamin and containing 0 or 2.5 g/kg α-lipoic acid for 22 days. Sesamin and α-lipoic acid decreased serum lipid concentrations and the combination of these compounds further decreased the parameters in an additive fashion. These compounds reduced the hepatic concentration of triacylglycerol, the lignan being less effective in decreasing this value. The combination failed to cause a stronger decrease in hepatic triacylglycerol concentration. The combination of sesamin and α-lipoic acid decreased the activity and mRNA levels of hepatic lipogenic enzymes in an additive fashion. Sesamin strongly increased the parameters of hepatic fatty acid oxidation enzymes. α-Lipoic acid antagonized the stimulating effect of sesamin of fatty acid oxidation through reductions in the activity of some fatty acid oxidation enzymes and carnitine concentration in the liver. This may account for the failure to observe strong reductions in hepatic triacylglycerol concentration in rats given a diet containing both sesamin and α-lipoic acid.