Effects of Dietary Alpha-lipoic Acid on Anti-oxidative Ability and Meat Quality in Arbor Acres Broilers

Lipoamide Alleviates Oxidized Fish Oil-Induced Host Inflammatory Response and Oxidative Damage in the Oviduct of Laying Hens

Fish oil (FO) is an important source of lipid in functional food and aquafeeds. However, the harmful effects of oxidized fish oil (OFO) on host metabolism and reproductive health are not yet clear. In addition, lipoamide (LAM) has been widely studied as an agent for alleviating various diseases associated with oxidative disruption. Therefore, in the current study, to investigate the effects of LAM in alleviating OFO-induced decline in reproductive performance and oxidative damage to the oviduct in laying hens. We constructed a 1% fresh FO model, a 1% OFO model, and a LAM model with 1% OFO (OFO + LAM) added at 100 mg/kg to explore the antioxidant effect of LAM. Herein, these results were evaluated by breeding performance, immune responses, estrogen, and antioxidant indices of serum samples, as well as the number of follicles and antioxidant parameters of oviducts. From the results, compared with the FO group, OFO significantly decreased the egg-laying rate, increased the contents of total protein (TP) and inflammatory factors [tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-8, and interferon γ (INF-γ)], and reduced the concentrations of anti-oxidation [total antioxidant (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), glutathione (GSH), glutathione reductase (GR), catalase (CAT), and hydroxyl radical scavenging activity (HRSA)] in serum samples, as well as reduced the levels of anti-oxidation indexes in oviduct tissues (p < 0.05). Of note, the supplementation of LAM could significantly increase the laying performance, improve the levels of serum immunoglobulins (IgA, IgG, and IgM), serum estrogen [progesterone (P) and estradiol (E2)], and serum antioxidant parameters (T-AOC, T-SOD, GSH-Px, GSH, GR, CAT, and HRSA) and decrease the concentrations of serum inflammatory cytokines (TNF-α, IL-6, IL-8, and INF-γ) in laying hens following OFO administration (p < 0.05). In addition, LAM could dramatically increase the contents of antioxidant factors (p < 0.05) in oviducts and enhance the secretion capacity of the uterine part. Taken together, OFO caused host metabolic dysfunction, oxidative damage, uterine morphological abnormalities, and alterations of ovarian function. These results suggested that LAM administration could alleviate host metabolic dysfunctions and inflammatory damage, and then ameliorate oxidative damage in the oviduct induced by OFO, ultimately improving reproductive function.

Effect of stocking density and alpha-lipoic acid on the growth performance, physiological and oxidative stress and immune response of broilers

Objective

The study was conducted to evaluate the effect of stocking density and alpha-lipoic acid (ALA) on the growth performance, feed utilization, carcass traits, antioxidative ability and immune response of broilers.

Methods

A total of 1,530 22-day-old male broilers (Arbor Acres) with comparable body weights (731.92±5.26) were placed into 18 cages (2.46×2.02 m) in groups of 75 birds (15 birds/m², 37.5 kg/m²; low stocking density [LD]), 90 birds (18 birds/m², 45.0 kg/m²; high stocking density [HD]) and 90 birds with 300 mg/kg ALA added to the basal diet (18 birds/m², 45.0 kg/m²; HD+ALA, high stocking density+α-lipoic acid); each treatment was represented by 6 replicates. The experimental period was 3 weeks.

Results

The results showed that the high stocking density regimen resulted in a decreased growth, feed conversion ratio, carcass weight, thigh yield and bursa weight relative to body weight (p<0.05) on d 42. The abdominal fat yield in the HD+ALA group was lower (p = 0.031) than that of the LD group at 42 d. The superoxide dismutase and glutathione peroxidase activities in serum were increased, and malondialdehyde content decreased after adding ALA product (p<0.05) on d 42. Additionally, the serum concentrations of immunoglobulin A (IgA) and IgG were decreased (p<0.05) and the level of diamine oxidase was higher (p< 0.01) in the HD group on d 42.

Conclusion

The high stocking density significantly decreased broiler growth performance, feed utilization and carcass traits, increased physiological and oxidative stress and induced intestinal mucosal injury. The supplementation of ALA product in broiler diet at 300 mg/kg may reduce the adverse effects of high stocking density-mediated stress by maintaining the antioxidant system and humoral immune system.

Effects of dietary vitamin C, vitamin E, and alpha-lipoic acid supplementation on the antioxidant defense system and immune-related gene expression in broilers exposed to oxidative stress by dexamethasone

Vitamin C, vitamin E, and alpha-lipoic acid (ALA) are potent nutritional antioxidants, which are important for enhancing immunity. This study compared the effects of supplementation with vitamin C, vitamin E, or ALA on the antioxidant defense system and the expression of immune-related genes under oxidative stress induced by dexamethasone (DEX) in broilers. In total, 240 one-day-old female Recessive White Rock chickens were assigned randomly to either a basal diet (control group) or basal diet supplemented with vitamin C (200 mg/kg diet), vitamin E (100 mg/kg), or ALA (500 mg/kg) for 28 d starting from hatching. At 21 d of age, birds fed the ALA-supplemented diet had the highest plasma total antioxidant capacity (T-AOC) and superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) enzyme activities, and the lowest plasma malondialdehyde (MDA) activity, as well as the lowest mRNA gene expression levels of interferon gamma (IFN-γ) and lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF). At 23 d of age, the broilers in the 3 treatment groups were injected in the thigh muscle with DEX for 3 alternating days. In addition, the control group was divided into 2 equal groups, in which one was injected with saline and the other was injected with DEX. At 28 d of age, the DEX-ALA group (P < 0.05) had the highest activity levels for T-AOC, T-SOD, and GSH-PX in the plasma and liver (P < 0.05), and the greatest reduction in the MDA level. Dietary ALA significantly decreased the mRNA expression levels of the interleukin 1 β (IL-1β), IL-6, IFN-γ, and LITAF genes compared with the other groups during oxidative stress by DEX. In conclusion, this study suggests that in broilers, ALA is more effective for normalizing the oxidative stress induced by DEX than vitamin C or vitamin E.

Molecular Mechanisms of Lipoic Acid Protection against Aflatoxin B₁-Induced Liver Oxidative Damage and Inflammatory Responses in Broilers

Alpha-lipoic acid (α-LA) was evaluated in this study for its molecular mechanisms against liver oxidative damage and inflammatory responses induced by aflatoxin B₁ (AFB₁). Birds were randomly allocated into four groups with different diets for three weeks: a basal diet, a 300 mg/kg α-LA supplementation in a basal diet, a diet containing 74 μg/kg AFB₁, and 300 mg/kg α-LA supplementation in a diet containing 74 μg/kg AFB₁. In the AFB₁ group, the expression of GSH-P_X mRNA was down-regulated (p < 0.05), and the levels of lipid peroxide and nitric oxide were increased (p < 0.05) in the chicken livers compared to those of the control group. Additionally, the mRNA level of the pro-inflammatory factor interleukin-6 was up-regulated significantly (p < 0.05), the protein expressions of both the nuclear factor kappa B (NF-κB) p65 and the inducible nitric oxide synthase were enhanced significantly (p < 0.05) in the AFB₁ group. All of these negative effects were inhibited by α-LA. These results indicate that α-LA may be effective in preventing hepatic oxidative stress, down-regulating the expression of hepatic pro-inflammatory cytokines, as well as inhibiting NF-κB expression.

Effects of Dietary L-carnosine and Alpha-lipoic Acid on Growth Performance, Blood Thyroid Hormones and Lipid Profiles in Finishing Pigs

The present study was conducted to determine the effects of L-carnosine (LC) and/or alpha-lipoic acid (ALA) supplementation on growth performance, blood thyroid hormones and lipid profiles in finishing pigs. A total of 40 (Landrace×Yorkshire) pigs with an initial body weight of 57.93±3.14 kg were randomly allocated to 4 experimental diets using a 2×2 factorial arrangement with 2 LC supplemental levels (0 or 0.1%) and 2 ALA supplemental levels (0 or 0.03%) in basal diets. The results showed that pigs fed LC-supplemented diets increased final live weight, average daily gain, and average daily feed intake compared to those of pigs fed without LC-supplemented diets (p<0.05). Dietary supplementation with ALA did not affect the growth performance and carcass traits of pigs (p>0.05). Additionally, LC supplementation increased serum triiodothyronine, thyroxine levels, and ALA supplementation increased serum triiodothyronine levels (p<0.05). Serum total cholesterol and triglycerides levels were significantly decreased in LC and ALA supplemented groups, respectively (p<0.05). Moreover, serum low density lipoprotein cholesterol levels were lower in the ALA-supplemented groups than those of pigs fed without ALA-supplemented diets (p<0.05). However, no significant LC×ALA interaction effect on growth performance, blood thyroid hormones and lipid profiles was found. This study suggested that dietary supplementation of LC resulted in better growth performance compared to that of ALA supplementation. L-carnosine and/or ALA supplementation positively modified blood lipid profiles, which may have the potential to prevent cardiovascular diseases.

Protective Efficacy of Alpha-lipoic Acid against AflatoxinB1-induced Oxidative Damage in the Liver

Alpha-lipoic acid (α-LA) is not only involved in energy metabolism, but is also a powerful antioxidant that can protect against hepatic oxidative stress induced by some drugs, toxins, or under various physiological and pathophysiological conditions. Here, we investigated the effect of α-LA against liver oxidative damage in broilers exposed to aflatoxin B₁ (AFB₁). Birds were randomly divided into four groups and assigned different diets: basal diet, 300 mg/kg α-LA supplementation in basal diet, diet containing 74 μg/kg AFB₁, and 300 mg/kg α-LA supplementation in diet containing 74 μg/kg AFB₁, for 3 weeks. The results revealed that the addition of 300 mg/kg α-LA protected against the liver function damage of broilers induced by chronic low dose of AFB₁ as estimated by a significant (p<0.05) change in levels of plasma total protein, albumin, alkaline phosphatase and the activities of liver glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase. The histopathological analysis also showed that liver tissues were injured in the AFB₁ diet, but this effect was alleviated by the addition of 300 mg/kg α-LA. Additionally, AFB₁ induced a profound elevation of oxidative stress in birds, as indicated by an increase in malondialdehyde level, a decrease in glutathione peroxidase activity and a depletion of the glutathione content in the liver. All of these negative effects were inhibited by treatment with α-LA. Our results suggest that the inhibition of AFB₁-induced excess production of lipid peroxides and the maintenance of intracellular antioxidant status may play important roles in the protective effects of α-LA against AFB₁-induced oxidative damage in the liver.

Effects of Dietary Alpha-lipoic Acid and Acetyl-L-carnitine on Growth Performance and Meat Quality in Arbor Acres Broilers

An experiment was conducted to evaluate the effects of dietary alpha-lipoic acid (LA) and acetyl-L-carnitine (ALC) on growth performance, carcass characteristics and meat quality in Arbor Acres broilers. A total of 486 1-d-old male Arbor Acres broilers were randomly allocated to 9 dietary treatments, 9 treatments were group A (0 mg/kg LA and 0 mg/kg ALC), group B (50 mg/kg LA and 0 mg/kg ALC), group C (100 mg/kg LA and 0 mg/kg ALC), group D (0 mg/kg LA and 50 mg/kg ALC), group E (50 mg/kg LA and 50 mg/kg ALC), group F (100 mg/kg LA and 50 mg/kg ALC), group G (0 mg/kg LA and 100 mg/kg ALC), group H (50 mg/kg LA and 100 mg/kg ALC), group I (100 mg/kg LA and 100 mg/kg ALC). Birds were slaughtered at 42 days old. Average daily gain (ADG), average feed intake (AFI), feed conversion rate (FCR), eviscerated rate, breast muscle percentage, thigh muscle percentage, abdominal fat percentage, liver weight, muscle color (L* value, a* value, b* value), pH values at 45 min and 24 h postmortem were measured. Results showed that there existed an interaction between LA and ALC in growth performance of broilers, carcass traits and meat quality. The overall result is that high level of LA and ALC led to lower AFI, ADG (p<0.01), lower abdominal fat percentage, liver weight (p<0.01), lower L* value, a* value, and b* value of breast muscle, L* value of thigh muscle (p<0.05), and higher FCR (p<0.01), eviscerated rate (p<0.01), breast muscle percentage, thigh muscle percentage (p<0.05), a* value, pH 45 min and pH 24 h of thigh muscle (p<0.01). These results suggested that dietary LA and ALC contributed to the improvement of meat quality in broilers.

Nutritional factors affecting abdominal fat deposition in poultry: a review

The major goals of the poultry industry are to increase the carcass yield and to reduce carcass fatness, mainly the abdominal fat pad. The increase in poultry meat consumption has guided the selection process toward fast-growing broilers with a reduced feed conversion ratio. Intensive selection has led to great improvements in economic traits such as body weight gain, feed efficiency, and breast yield to meet the demands of consumers, but modern commercial chickens exhibit excessive fat accumulation in the abdomen area. However, dietary composition and feeding strategies may offer practical and efficient solutions for reducing body fat deposition in modern poultry strains. Thus, the regulation of lipid metabolism to reduce the abdominal fat content based on dietary composition and feeding strategy, as well as elucidating their effects on the key enzymes associated with lipid metabolism, could facilitate the production of lean meat and help to understand the fat-lowering effects of diet and different feeding strategies.

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 lipoic acid influences antioxidant capability and oxidative status of broilers

The effects of lipoic acid (LA) on the antioxidant status of broilers were investigated. Birds (1 day old) were randomly assigned to four groups and fed corn-soybean diets supplemented with 0, 100, 200, 300 mg/kg LA, respectively. The feeding program included a starter diet from 1 to 21 days of age and a grower diet from 22 to 42 days of age. Serum, liver and muscle samples were collected at 42 days of age. For antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in serum, liver and breast muscle significantly increased in chickens fed with LA. The concentration of malondiadehyde (MDA), an indicator of lipid peroxidation, was significantly lower in serum, liver and leg muscle in birds that received LA than in the control group. Treatments with LA significantly increased glutathione (GSH) content in liver and increased α-tocopherol content in leg muscle as compared to the control. These results indicate that dietary supplementation with 300 mg/kg LA may enhance antioxidant capability and depress oxidative stress in broilers.

Effects of alpha-lipoic acid supplementation on antioxidative ability and performance of sows and nursing piglets

The current study was carried out to determine the effects of alpha-lipoic acid (LA) supplementation during late-gestation and lactation on antioxidative ability and performance of sows and their nursing piglets. A total of 160 multiparous sows were randomly allocated to four treatments with 40 replicates per treatment according to parity number and backfat (BF) thickness. Sows were fed 1 of 4 diets from day 85 of gestation to day 21 of lactation. Diets were control without LA; 400 ppm LA supplementation; 600 ppm LA supplementation; and 800 ppm LA supplementation. BF thickness of sows was determined on day 85 and 110 of gestation and days 1 and 21 of lactation. Piglet bodyweight was measured at birth, days 7, 14 and 21. Blood samples were obtained from the sows, and average daily feed intake (ADFI) of the sows during lactation was recorded. There were no differences in BF thickness or ADFI among treatment groups. Dietary LA supplementation resulted in a decrease in blood urea nitrogen (p < 0.01) concentration at days 110 of gestation. Dietary 800 ppm LA increased serum glutathione peroxidase (GSH-Px) activity (p < 0.05) and reduced maleic dialdehyde levels (p < 0.01) of sows compared with the control diet at days 21 of lactation. Alpha-lipoic acid supplementation increased the birthweight and weaning weight of piglets (p < 0.01) compared with the control group. Weight gains of piglets from sows fed the 800 ppm LA diets were greater (p < 0.01) between days 7 and 14 compared with piglets from control sows. Weight gains of piglets from sows fed the LA-supplemented diets were greater between days 14 and 21 (p < 0.05) and between days 1 and 21 (p < 0.01) compared with piglets from control-fed sows. In conclusion, the results indicate that antioxidant LA was effective in enhancing antioxidant enzymes activity and improving the performance of sows and their nursing piglets.