Influence of dietary fat and vitamin E supplementation on α-tocopherol levels and fatty acid profiles in chicken muscle membranal fractions and on susceptibility to lipid peroxidation

Effects of dietary vitamin E supplementation on growth performance, slaughter performance, antioxidant capacity and meat quality characteristics of finishing bulls

This study was conducted to investigate the effects of dietary supplementation of vitamin E (VE) on growth performance, slaughter performance, antioxidant capacity and meat quality characteristics of finishing bulls. Twenty Yanbian cattle (bulls) with initial body weight (BW) 485 ± 42 kg were randomly divided into two groups (control and treatment groups) and participated in a100-day finishing trial. The control group (CON) was fed a basal diet (total mixed ration, TMR). The treatment group was fed a basal diet supplemented with VE (provided as α-tocopherol acetate, 700 IU/bull/day). VE supplementation significantly increased the average daily gain (ADG) of finishing bulls, the beef marbling score, meat color parameters (a* [redness]), intramuscular fat content, the concentration of catalase, superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), VE and matrix metalloproteinases (MMP-13) in the serum and muscle tissue (P < 0.05). VE supplementation significantly decreased drip loss and cooking loss of the beef, the concentration of nitric oxide (NO) in the serum and muscle tissue, the concentration of malondialdehyde in the muscle tissue (P < 0.05), and tended to decrease the feed: gain (P = 0.077) and shear force (P = 0.062) of the beef. In conclusion, VE supplementation can improve the meat quality parameters of finishing bulls, especially the improvement of beef tenderness. The improvement of beef tenderness by VE supplementation may be related to the increase of MMPs concentration, and a potential mechanism for the secretion of MMPs by VE supplementation may be related to its antioxidant capacity.

Effect of Feeding Olive Pomace Acid Oil on Dark Chicken Meat Lipid Composition, Oxidative Stability, Color, and Sensory Acceptance

This study evaluated the effect of using olive pomace acid oil (OPAO) instead of crude palm oil (PO) or refined olive pomace oil (ROPO) on lipid composition, lipid oxidation, and quality of chicken meat. Broiler chickens were fed diets with 6% of PO, ROPO, or OPAO, and deboned legs with skin were sampled. Fresh and refrigerated (commercial conditions; 7 days) chicken meat samples were assessed for fatty acid (FA) composition, tocopherol (T) and tocotrienol (T3) content, lipid oxidative stability, 2-thiobarbituric acid (TBA) values, volatile compounds, color, and sensory acceptance. Using ROPO and OPAO led to meat richer in monounsaturated FAs and OPAO to lower α-T levels compared to PO. Oxidative stability, TBA values, volatile compounds, and overall acceptance of meat were not affected by diet. Refrigeration increased TBA values and some volatile compounds' concentrations, but it did not decrease redness or consumers' overall acceptance. Therefore, the OPAO used was an adequate fat source for chicken diets at 6%, as it produced dark meat lower in saturated FAs than PO without affecting lipid oxidation or overall acceptance. According to this, upcycling OPAO as an energy source in chicken diets would be possible, which can contribute to the sustainability of the food chain.

Evaluating the impact of organic chromium with flax seed in broiler diets: effects on production performance, breast muscle pathology, and meat quality aspects

The study investigated the impact of organic chromium (Cr) and flax seed supplementation on live performance, carcass yield, muscle lipid profile, histopathological aspects, and meat quality parameters in broilers. Ninety (n = 90), day-old Cobb chicks were fed a corn-soybean meal-based diet containing 0% flax seed (Control), 10% flax seed (Diet 1) and Diet 1 + 0.05% organic Cr (Diet 2). The experiment was a completely randomized design and chicks were placed in 6 pens with 5 chicks per each pen. Pen was the experimental unit for production performance and bird collected from each pen was considered as experimental unit for all other analysis. On d 43, 45, and 48, one bird per pen were euthanized. A one-way ANOVA was performed with diet as the main factor and significance was set at P < 0.05. Significant differences between each treatment were analyzed by GLM Lean Square Method and Tukey's Honestly Significant Difference test. Weight gain and feed:gain was determined at d (1-11), (12-21), and (22-42). For all response variables, the effects among dietary treatments were compared using ANOVA separately using SAS 9.4. P -values were considered significant at ≤0.05. At d 22, Diet 1 and Diet 2 birds had lower BW and feed:gain than Control (P < 0.05). At d 42, Diet 2 birds were higher in BW with improved feed:gain when compared to Diet 1 (P < 0.05) but were not different from Control (P > 0.05). The overall weight gain was higher in Diet 2 and Control compared to Diet 1 (P < 0.05) and overall feed:gain was the highest in Control than the experimental diets (P < 0.05). Histopathological changes in breast muscle including floccular/vacuolar degeneration, fibrosis, lipidosis, interstitial inflammation, and muscle lysis were less pronounced in Diet 1 compared to Diet 2 (P < 0.05). Breast muscle total fat and cholesterol was lower in Diet 1 compared to Control (P < 0.05). Diet 1 and Diet 2 increased (>2-5 fold) total and long chain (≥20C) n-3 fatty acids (FA) in the breast muscle (P < 0.05) compared to Control. Lipid peroxidation products measured as thiobarbituric acid reactive substances were lower in the breast muscle of Diet 1 and Diet 2 compared to Control (P < 0.05). Phospholipid n-3 FA molecular species in phosphatidylcholine (PC) 36:5, 38:6, and phosphatidylethanolamine (PE) 36:5 were higher in breast muscle of Diet 1 than Control (P < 0.05) and was not different from Diet 2 (P > 0.05). A decrease in n-6 FA species (36:4 and 38:4) was observed in PC and PE of Diet 1and Diet 2 compared to Control (P < 0.05). Drip loss values were reduced in Diet 1 and Diet 2 versus Control (P < 0.05). As consumer demand for n-3 FA-rich poultry products are on the rise, Cr may serve as a feed supplement that could be used in broilers fed flax seed-containing diets for enriching edible tissues with n-3 FA, while enhancing production performance.

Gamma-irradiated rosemary (Rosmarinus officinalis) dips treatment effect on quality of rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage

The effect of the gamma-irradiated extract of rosemary and butylated hydroxyanisole (BHA) antioxidant on sensory, chemical and microbiological changes of rainbow trout fillets stored at 4 ± 1°C was investigated for 16 days. The fillets were divided into: control (C), 750 and 1500 rosemary extract (RE) (immersed in 750 and 1500 ppm rosemary extract); 250 and 500 gamma-irradiated rosemary (GIR), (immersed in 250 and 500 ppm gamma-irradiated rosemary) and 250 and 500 BHA (immersed in 250 and 500 ppm BHA). The shelf life of fillets was reported to be 8 days for C, and 12 days for 500 GIR group according sensory, microbiological and chemical parameters. The pH, peroxide value (PV), total volatile basic nitrogen (TVB-N), free fatty acid (FFA), thiobarbituric acid (TBA), psychrotrophic counts (PTC), and total viable aerobic bacterial counts (TVC) values were 7.62 ± 0.21, 17.17 ± 1.6, 51.07 ± 1.1, 6.05 ± 0.13, 3.42 ± 0.18, 12.03 ± 0.19, and 13.16 ± 0.16 respectively for C group and also, 7.42 ± 0.16, 15.2 ± 1.7, 42.5 ± 1.5, 4.48 ± 0.39, 2.59 ± 0.15, 9.98 ± 0.15, and 10.5 ± 0.15 respectively for 500 GIR group. Finally, the following trend in effectiveness was reported: gamma-irradiated rosemary PBS extract > BHA > rosemary PBS extract.

Soybean Oil Replacement by Poultry Fat in Broiler Diets: Performance, Nutrient Digestibility, Plasma Lipid Profile and Muscle Fatty Acids Content

Simple Summary

The effect of partial or complete substitution of soybean oil (SO) by poultry fat (PF) on growth, nutrient digestibility, plasma lipids, and the pectoral muscle content of fatty acids (FAs) was examined in this study. Dietary PF supplementation improved breast muscle FA profile but did not affect muscle vitamin E content and liver thiobarbituric acid reactive substances (TBARS). By adding PF to the diet, economic efficiency was greatly improved in a dose-dependent manner. Therefore, the results of this study revealed that PF could be used as a partial or total replacement of SO in broiler nutrition without affecting their performance or physiological response with a tendency to improve their meat products.

Abstract

Continuous genetic improvements of commercial broiler strains has led to the necessity of using fats in their rations to fulfill a large portion of the energetic requirements. Several fat sources have been introduced in poultry nutrition, such as rendering poultry fat (PF) an available and cheap lipid source compared to conventional sources such as soybean oil (SO). The present study investigated the effect of partial or full replacement of SO by PF on performance, nutrient digestibility, blood lipids, and fatty acids (FAs) content of pectoral muscle. Four hundred and eighty one-day-old male Ross-308 chicks were distributed into four experimental groups (12 replicates each): the first group (control) was fed a diet formulated with soybean oil as a fat source while the second to fourth groups (PF25, PF50, and PF100) were fed diets formulated with 25, 50 and 100% of PF as a fat source instead of SO. Results revealed no synergistic effect between SO and PF in any of the studied parameters. Replacing SO by PF did not alter birds’ growth, carcass characteristics, and plasma indices of birds. Abdominal fat% was increased (p < 0.01) in PF50 and PF100. Dry matter digestibility was improved (p < 0.05) in PF50 and PF100, while crude fat and protein digestibility was not affected. Contents of palmitic and docosahexaenoic acids in the pectoral muscle of PF50 and PF100 were reduced (p < 0.01) while concentrations of oleic and linolenic acids, total unsaturated FAs, and polyunsaturated FAs/Saturated FAs ratio were elevated (p < 0.05) in the same groups. Liver thiobarbituric acid reactive substances (TBARS) and muscle vitamin E contents were not altered. The dietary addition of PF greatly improved economic parameters. In conclusion, PF can be used as a lipid source in broiler diets to produce inexpensive meat while maintaining its growth performance.

Dietary vitamin E reaches the mitochondria in the flight muscle of zebra finches but only if they exercise

Whether dietary antioxidants are effective for alleviating oxidative costs associated with energy-demanding life events first requires they are successfully absorbed in the digestive tract and transported to sites associated with reactive species production (e.g. the mitochondria). Flying birds are under high energy and oxidative demands, and although birds commonly ingest dietary antioxidants in the wild, the bioavailability of these consumed antioxidants is poorly understood. We show for the first time that an ingested lipophilic antioxidant, α-tocopherol, reached the mitochondria in the flight muscles of a songbird but only if they regularly exercise (60 min of perch-to-perch flights two times in a day or 8.5 km day-1). Deuterated α-tocopherol was found in the blood of exercise-trained zebra finches within 6.5 hrs and in isolated mitochondria from pectoral muscle within 22.5 hrs, but never reached the mitochondria in caged sedentary control birds. This rapid pace (within a day) and extent of metabolic routing of a dietary antioxidant to muscle mitochondria means that daily consumption of such dietary sources can help to pay the inevitable oxidative costs of flight muscle metabolism, but only when combined with regular exercise.

Effect of Castor and Cashew Nut Shell Oils, Selenium and Vitamin E as Antioxidants on the Health and Meat Stability of Lambs Fed a High-Concentrate Diet

Functional oils are known for their compounds with antioxidant, antimicrobial and anti-inflammatory properties, and are used in ruminant nutrition as alternatives to chemicals in order to improve performance. This study aimed to compare the influence of castor and cashew nut shell oils with pure organic selenium (hydroxy-selenomethionine) plus vitamin E, which are known and well-stablished antioxidants, on the performance traits, shelf life and microbial quality of the meat, physiological functions and oxidative stress control of lambs. Thirty-two Dorper x Santa Ines lambs (initial bodyweight of 22.42 ± 3.9 kg and 60 days of age) were submitted to a diet consisting of Cynodon dactylon hay (6%) and concentrate (94%). The animals were divided into four treatments: control, without additives; functional oils (FO), 0.50 g/kg DM of castor and cashew nut shell oils; hydroxy-selenomethionine and vitamin E (SeE), 0.50 mg/kg of organic selenium and 100 IU/kg DM of vitamin E; FO plus SeE, at the same doses as the other groups. Blood samples were collected after 1, 30 and 53 days on feed. After 54 days, the lambs were slaughtered and rumen health, carcass and meat traits, shelf life, and microbiological quality were evaluated. There were no differences in performance or carcass traits. A higher muscle and serum Se concentration (p < 0.0001), lower lipid peroxidation in meat during display (p < 0.0001), and a lower count of psychrotrophic microorganisms on day 5 were observed in the SeE and FO plus SeE groups. The treatments reduced the counts of Enterobacteriaceae, and Staphylococcus spp. FO animals showed higher GSH-Px activity on day 30, while the peroxidase activity was higher in FO plus SeE animals (p = 0.035). SeE and FO plus SeE animals had lower serum ALT and AST levels. Functional oils improved the microbiological quality of meat. Hydroxy-selenomethionine and vitamin E prevented oxidative stress, lipid peroxidation, and microbial spoilage.

Fatty acid profiles of crop contents of free-living psittacine nestlings and of commercial hand-feeding formulas

Research on psittacine nutrition is limited, and nestling requirements are poorly understood. This study analysed fatty acid (FA) profiles of crop contents of free-living scarlet macaws (Ara macao, n = 18), red-and-green macaws (Ara chloropterus, n = 5), Cuban parrots (Amazona leucocephala bahamensis, n = 27), lilac-crowned Amazons (Amazona finschi, n = 33) and thick-billed parrots (Rhynchopsitta pachyrhyncha, n = 32). The same analysis was carried out on 15 commercial parrot hand-feeding formulas. The mean FA concentration of the crop samples of each species ranged from 15% to 53% DM for crop samples and ranged from 6% to 22% for hand-feeding formulas. Long-chain FA represented over 92% of all FA in the crop samples and over 81% of all FA in the commercial formulas. Parrot species shared similarities in saturation profiles of crop samples, ranging between 13%-29% saturated fatty acids (SFA), 12%-40% monounsaturated fatty acids (MUFA) and 39%-58% polyunsaturated fatty acids (PUFA). All studied psittacines, except for the red-and-green macaw, were within the range of values for hand-rearing formulas. Palmitic acid was the most common SFA in scarlet macaws, red-and-green macaws, Cuban parrot, thick-billed parrot and in all but one commercial formula. Palmitic and stearic acids dominated the SFA in the samples of the Lilac-crowned Amazon. Oleic acid was the most common MUFA in all hand-feeding formulas as well as in the crop samples, except for the lilac-crowned amazon and the thick-billed parrot where vaccenic acid dominated. Linoleic acid was by far the most common PUFA found in the crop samples as well as in the hand-feeding formulas. PUFA were largely dominated by the n6 family, both in the crop samples and the formulas. The data presented on nestling diets of free-living parrot species provide a foundation for future researchers to test whether increasing FA concentration in hand-feeding formulas improves nestling development or if species-specific formulas will be advantageous.

Effects of Microencapsulated Blend of Organic Acids and Essential Oils as a Feed Additive on Quality of Chicken Breast Meat

The present study aims to investigate the effect of dietary supplementation based on a blend of microencapsulated organic acids (sorbic and citric) and essential oils (thymol and vanillin) on chicken meat quality. A total of 420 male Ross 308 chicks were randomly assigned to two dietary treatments: the control group was fed with conventional diet (CON), while the other group received the control diet supplemented with 0.5% of a microencapsulated blend of organic acids and essential oils (AVI). In breast meat samples, intramuscular fat content and saturated/polyunsaturated fatty acids ratio were reduced by AVI supplementation (p < 0.05). Moreover, atherogenic (p < 0.01) and thrombogenic (p < 0.05) indices were lower in AVI than CON treatment. AVI raw meat showed a lower density of psychrotrophic bacteria (p < 0.05) at an initial time, and higher loads of enterococci after 4 days of refrigerated storage (p < 0.05). No contamination of Listeria spp., Campylobacter spp., and Clostridium spp. was found. TBARS values of the cooked meat were lower in the AVI treatment compared to CON (p < 0.01). Among colour parameters, a*, b* and C* values increased between 4 and 7 days of storage in AVI cooked meat (p < 0.05). Overall, organic acids and essential oils could improve the quality and shelf-life of poultry meat.

Oxidative stability and Sensoric acceptability of functional fish meat product supplemented with plant-based polyphenolic optimal extracts

Background

Fish meat and its products are usually accepted as good source of biological high value food components and especially for polyunsaturated fatty acids. The quality of fish meat products is considered to be decreased by the lipid peroxidation which leads to reduction in nutritional quality, financial loss and severe health problems. Many tactics are present to reserve their quality and safety. In the present investigation, the extraction and supplementation of optimal total polyphenol extracts (TPC) from vegetable and fruit by₋products was explored for lipids oxidative stability and sensoric acceptability of functional fish product samples.

Methods

Vegetable and fruit by₋products (cabbage leaves and banana peels) were collected from local fruits and vegetables processing industries. A 3₋level five factor Box₋Behnken design was used to study the effect of extraction/sonication temperature (°C), amplitude level, water/meal ratio, extraction/sonication time (minutes) and pH conditions for maximum yield of TPC from dried vegetable and fruit samples. The TPC samples were analyzed for chemical composition (total polyphenols, cyanogenic contents and tannins). Natural TPC extracts were supplemented at different concentration (0.5, 1 and 1.5%) to fish meat for preparation of different meat ball samples. The fish meat product samples without supplementation of TPC extract were kept as control. The partial/parfrying of the products was carried out to determine the lipid stability (peroxide value and free fatty acids) stored at refrigerator (for 9 days) and at − 18 °C in a freezer for a storage period of 60₋days. The sensoric analysis (color, flavor and overall acceptability) was performed at different storage intervals for experimental treatments.

Results

The percent values of TPC yield from cabbage leave and banana peel samples ranged from a from minimum value of 9.8 ± 0.12% to a maximum value of 19.8 ± 0.15% for cabbage leaves and minimum value of 15.55 ± 0.13% to a maximum value of 24.4 ± 0.17% for banana peels, respectively. The results revealed that extraction conditions significantly affect the TPC yield from cabbage leaves and banana peels. The cabbage leaves and banana peels contain up to 4.8% total phenolics, cyanogenic compounds (1.44 − 1.47 ± 0.14) and tannins (6.55–7.90 ± 0.22). Peroxide values (meqO₂ /kg) of meat balls treated with TPC extracts at 4 °C were in the range of 1.31 ± 0.12 to 3.10 ± 0.20 while at − 18 °C ranged was found 1.31 ± 0.12 to 1.55 ± 0.17, respectively. Peroxide values of all the treatments increased at the end of second interval then decreased at the end of last storage interval. Peroxide values of all treatments were higher and significantly different at the beginning and the end of the storage period (p <  0.05). In a similar way, free fatty acids and moisture content values trend was recorded for all experimental treatments. Sensory scores of fish product samples for color, flavor and overall acceptability showed a significant difference in sensory scores at refrigeration temperatures where sensory scores of fish product samples decreased significantly (p <  0.05) throughout refrigeration storage. Whereas, the sensory scores at the − 18 °C shows the good sensory characteristics, relatively.

Conclusions

Phenolic extracts containing antioxidant status can interact with free lipidperoxy or lipidoxy free radicals (formed in result of lipid oxidation) and hence stopping their further self₋breakdown. Plant₋based phenolic extracts can be used to decrease oxidation process and increase the shelf life of fish meat products. Additional studies should be undertaken to determine the maximal shelf life of food products supplemented with different plant₋based polyphenol extracts and treatment of nutritional disorders through their absorption, metabolism and distribution pattern into biological tissues.

Antioxidant status, meat oxidative stability and quality characteristics of lambs fed with hesperidin, naringin or α-tocopheryl acetate supplemented diets

BACKGROUND

Dietary supplementation of sheep with bioactive compounds such as citrus flavonoids appears as a great alternative for improving meat antioxidant capacity and could also have beneficial effects on growth performance, carcass traits and meat quality characteristics. An experiment was therefore conducted to examine the effects of hesperidin or naringin dietary supplementation on lambs' growth performance, antioxidant status and meat quality characteristics. Forty-four male 3-month-old Chios lambs were randomly assigned to four groups: C, fed with a basal diet, or H or N or VE offered the same diet further supplemented with hesperidin at 2500 mg or naringin at 2500 mg or α-tocopheryl acetate (vitamin E) at 200 mg kg^-1 feed respectively. At the end of the experiment (day 35), samples of longissimus thoracis muscle were collected for meat quality evaluation.

RESULTS

Both flavonoids and vitamin E dietary supplementation reduced plasma malondialdehyde (MDA) levels on day 35 (P < 0.05). No significant differences were observed in performance traits and meat quality characteristics among the experimental groups (P > 0.05). Hesperidin and naringin also reduced MDA levels in meat stored at 4 °C for up to 8 days (P < 0.05), although to a lesser extent than α-tocopheryl acetate.

CONCLUSION

Incorporation of flavonoids in sheep diets resulted in an improvement of plasma and meat antioxidant capacity. © 2018 Society of Chemical Industry.

The interactive effect of dietary n-6: n-3 fatty acid ratio and vitamin E level on tissue lipid peroxidation, DNA damage in intestinal epithelial cells, and gut morphology in chickens of different ages

Feeding chickens diets high in n-3 fatty acids (FA) increases their incorporation into tissue lipids, but leads to oxidative stress in cells. This study investigated the effect of the dietary polyunsaturated FA ratio (PUFA n-6: n-3) and vitamin E (vE) level on DNA damage and morphological changes in the gut epithelium of chickens. One-day-old female broiler chicks (n = 176) were divided into 4 groups fed for 43 d diets with a high (HR) or low (LR) PUFA n-6: n-3 ratio and supplemented with 50 or 300 mg vE kg-1. Performance was calculated for periods of d 1 to 9, d 9 to 16, d 9 to 35, and d 9 to 42, while organs were sampled at d 9, d 17, d 36, and d 43. At d 17 and d 43, DNA damage of epithelial cells in the duodenum and jejunum was measured and duodenal and jejunal morphology was analyzed. HR diets improved FCR for the periods of d 1 to 9, d 9 to 16 and d 9 to 42, whereas the increased vE level improved FCR for the period of d 9 to 16. In the jejunum DNA damage was greater in chickens fed LR than HR diets at d 17 (P < 0.001) and the increased vE level promoted DNA damage in both intestinal segments (P < 0.02) in younger birds. The morphology of the duodenum was marginally affected by the diets, whereas LR diets in the jejunum reduced villus surface area at d 17 (P = 0.022), and mucosa thickness (P = 0.029) and villus height (P = 0.035) at d 43. The results indicated that feeding birds LR diets and vE levels significantly exceeding the recommendation induced DNA damage in epithelial cells, but this effect varied depending on the intestinal segment and the age of birds.

The diverse effects of α- and γ-tocopherol on chicken liver transcriptome

α-Tocopherol is the form of vitamin E with the highest biological value and is almost exclusively considered as vitamin E in feed and feed supplements. Because γ-tocopherol, the predominant form of vitamin E naturally present in chicken feed, is not considered as a source of vitamin E, its re-evaluation with newer methods might be important.Despite γ-tocopherol's lower estimated biological value, it has been shown to be effective in reducing reactive nitrogen species, regulating immune and inflammatory processes, and diminishing the risk of metabolic perturbations and associated diseases. A 30-day nutritional trial in broiler chickens (Ross 308) was conducted to investigate how specific forms of vitamin E (α- and γ-tocopherol) and their combination impact liver gene expression when oxidative susceptibility of the organism is induced by high n-3 polyunsaturated fatty acids (PUFA) intake (linseed oil). Thirty-six one-day-old male broilers were fed a diet enriched with 5% linseed oil. A control group (Cont; N = 10) was used as a reference group, Tα (N = 10) was supplemented with 67 mg/kg RRR-α-tocopherol, Tγ (N = 8) with 67 mg/kg RRR-γ-tocopherol, and Tαγ (N = 8) with a combination of 33.5 mg/kg of each tocopherol. Beside oxidative stress indicators, whole chicken genome microarray analysis was performed on liver RNA and selected differentially expressed genes were confirmed by real time quantitative PCR. α-Tocopherol alone and in combination with γ-tocopherol was able to prevent lipid oxidation, which was also supported by transcriptome analysis. The effect of γ-tocopherol was evident in the expression of genes involved in inflammatory processes and immune response, while α-tocopherol affected genes involved in lipid and cholesterol metabolism. Both isomers of vitamin E influenced the transcription of genes, which are related to improved fat oxidation and enhanced glucose sparing.

Supra-nutritional levels of α-tocopherol maintain the oxidative stability of n-3 long-chain fatty acid enriched subcutaneous fat and frozen loin, but not of dry fermented sausage

BACKGROUND

Meat products enriched with n-3 fatty acids are more prone to oxidation. The aim was to investigate whether supra-nutritional levels of α-tocopherol can enhance the colour and lipid oxidative stability of n-3 fatty acids enriched dry fermented sausages, frozen loins and subcutaneous fat. Pigs were fed a diet supplemented with 18 g kg(-1) fish oil and 50, 150 or 300 mg kg(-1) α-tocopheryl acetate. The control group received 12 g kg(-1) soy oil and 150 mg kg(-1) α-tocopheryl acetate.

RESULTS

α-Tocopherol levels of the frozen loin, dry fermented sausage and subcutaneous fat were elevated as a result of the dietary α-tocopherol supplementation. Lipid oxidation occurred to the same extend in the n-3 fatty acid enriched frozen loins when compared to the control group. In the subcutaneous fat enriched with n-3 fatty acids reduced lipid oxidation was found when comparing 50 mg kg(-1) versus 150 and 300 mg kg(-1) . However, in the dry fermented sausages no such effect was observed and higher TBARS values were found in the n-3 fatty acid enriched sausages compared to the control group. Colour parameters of the loin and subcutaneous fat were not affected, whereas some significant differences in the dry fermented sausages were found. The colour stability of the frozen loins was not affected by the dietary treatments.

CONCLUSION

Supra-nutritional levels of α-tocopherol maintain the oxidative stability of n-3 fatty acid enriched frozen loins and subcutaneous fat, but not of dry fermented sausages. © 2016 Society of Chemical Industry.

Carcass and meat quality traits of chickens fed diets concurrently supplemented with vitamins C and E under constant heat stress

The objective of this study was to determine if a diet supplemented simultaneously with vitamins C and E would alleviate the negative effects of heat stress, applied between 28 and 42 days of age, on performance, carcass and meat quality traits of broiler chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2×3 factorial arrangement (diet with or without vitamin supplementation and two ambient temperatures plus a pair-feeding group) and 16 replicates. Chickens were kept in thermoneutral conditions up to 28 days of age. They were then housed in groups of four per cage, in three environmentally controlled chambers: two thermoneutral (22.5 and 22.6°C) and one for heat stress (32°C). Half the chickens were fed a diet supplemented with vitamins C (257 to 288 mg/kg) and E (93 to 109 mg/kg). In the thermoneutral chambers, half of the chickens were pair-fed to heat stressed chickens, receiving each day the average feed intake recorded in the heat stress chamber in the previous day. Meat physical quality analyses were performed on the pectoralis major muscle. No ambient temperature×diet supplementation interaction effects were detected on performance, carcass, or meat quality traits. The supplemented diet resulted in lower growth performance, attributed either to a carry-over effect of the lower initial BW, or to a possible catabolic effect of vitamins C and E when supplemented simultaneously at high levels. Heat stress reduced slaughter and carcass weights, average daily gain and feed intake, and increased feed conversion. Growth performance of pair-fed chickens was similar to that of heat stressed chickens. Exposure to heat stress increased carcass and abdominal fat percentages, but reduced breast, liver and heart percentages. Pair-fed chickens showed the lowest fat percentage and their breast percentage was similar to controls. Heat stress increased meat pH and negatively affected meat color and cooking loss. In pair-fed chickens, meat color was similar to the heat stressed group. Shear force was not influenced by heat stress, but pair-fed chickens showed the tenderest meat. In conclusion, reduction in growth performance and negative changes in meat color in heat stressed chickens were attributed to depression in feed intake, whereas negative changes in body composition, higher meat pH and cooking loss were credited to high ambient temperature per se. Diet supplementation with vitamins C and E as antioxidants did not mitigate any of these negative effects.

The Influence of Naringin or Hesperidin Dietary Supplementation on Broiler Meat Quality and Oxidative Stability

An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin or naringin, on growth performance, carcass characteristics, breast meat quality and the oxidative stability of breast and thigh meat. Two hundred and forty 1-day-old Ross 308 broiler chickens were randomly assigned to 6 groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other five groups were given the same diets further supplemented with naringin at 0.75 g/kg (N1), naringin at 1.5 g/kg (N2), hesperidin at 0.75 g/kg (E1), hesperidin at 1.5 g/kg (E2) and a-tocopheryl acetate at 0.2 g/kg (E). At 42 days of age, 10 chickens per treatment group were slaughtered for meat quality and oxidative stability assessment. No significant differences were observed among groups in final body weight, carcass weight and internal organs weights (P>0.05) apart from liver that decreased linearly with increased levels of naringin (P-linear<0.05). Regarding the breast meat quality parameters, only redness (a*) value was higher in E1 and N1 group compared to VE group (P<0.05), while all the others i.e. shear values (N/mm²), pH₂₄, cooking loss (%) and L* and b* color parameters were not significantly different among groups (P>0.05). Measurement of lipid oxidation values showed that after hesperidin and naringin dietary supplementation, malondialdehyde values decreased in tissue samples in a dose depended manner (P-linear<0.05). In conclusion, hesperidin and naringin, positively influence meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing as important additives for both the consumer and the industry.

Oxidative damage to poultry: from farm to fork

Poultry and poultry meat are particularly susceptible to oxidative reactions. Oxidation processes have been for decades the focus of animal and meat scientists owing to the negative impact of these reactions on animal growth, performance, and food quality. Lipid oxidation has been recognized a major threat to the quality of processed poultry products. The recent discoveries on the occurrence of protein oxidation in muscle foods have increased the scientific and technological interest in a topic that broadens the horizons of food biochemistry into innovative fields. Furthermore, in recent years we have witnessed a growing interest in consumers on the impact of diet and oxidation on health and aging. Hence, the general description of oxidative reactions as harmful phenomena goes beyond the actual impact on animal production and food quality and reaches the potential influence of oxidized foods on consumer health. Likewise, the current antioxidant strategies aim for the protection of the living tissues, the food systems, and a potential health benefit in the consumer upon ingestion. Along these lines, the application of phytochemicals and other microelements (Se, Cu) with antioxidant potential in the feeds or directly in the meat product are strategies of substantial significance. The present paper reviews in a concise manner the most relevant and novel aspects of the mechanisms and consequences of oxidative reactions in poultry and poultry meat, and describes current antioxidant strategies against these undesirable reactions.

Effects of Citrus junos by-products fermented with multistrain probiotics on growth performance, immunity, caecal microbiology and meat oxidative stability in broilers

1. The present study was conducted to develop Citrus junos probiotics (CJP), using by-products of Citrus junos fermented with multispecies probiotic bacteria including Saccharomyces cerevisiae, Enterococcus faecium, Lactobacillus acidophilus and Bacillus subtilis. The effects of dietary CJP on the growth performance, immune status, caecal microbiology and meat oxidative stability of broiler were investigated. 2. A total of 240 one-day-old Ross broiler chicks were used in a 35-d experiment in which the chicks were randomly allotted to one of the 4 dietary treatments (0, 5, 10 and 20 g CJP/kg diet) in a completely randomised design. 3. Dietary supplementation of 5 g/kg CJP significantly increased body weight, average daily gain and average daily feed intake of broiler during the overall experimental period. 4. Serum immunoglobulin (Ig)M concentration was significantly increased by 10 and 20 g/kg CJP, whereas the IgG and IgA concentration remained unaffected. In addition, 20 g/kg CJP significantly inhibited proliferation of Escherichia coli without affecting the concentration of Lactobacillus or Bacillus spp. 5. A significant reduction in the thiobarbituric acid reactive substances values of breast and thigh meat was observed in response to increasing concentration of dietary CJP. 6. Thus, the results suggest that CJP up to a concentration of 20 g/kg can be used in the diet of broilers to improve immunity and to reduce caecal E. coli and TBARS values of breast and thigh meat without any adverse effects on growth performance.

Effect of cinnamon (Cinnamomum zeylanicum) essential oil supplementation on lamb growth performance and meat quality characteristics

A trial was conducted to examine the effect of cinnamon essential oil supplementation on lamb growth performance and meat quality. Sixteen male lambs were randomly assigned to two groups. The first group served as control and was given a basal diet, and the second group was given the same diet supplemented with cinnamon oil (1 ml/kg of concentrated feed) for 35 days. Incorporation of cinnamon oil did not affect growth performance (P>0.05). Meat pH, colour, water-holding capacity, shear force, intramuscular fat and lipid oxidation values of longissimus thoracis muscle were not significantly influenced by cinnamon oil supplementation (P>0.05). The post-inoculation counts of Salmonella enteritidis and Listeria monocytogenes on raw meat during refrigerated storage for 6 days did not differ (P>0.05) between the two groups. The results show that cinnamon oil supplementation may not have the potential to improve lamb growth performance and meat quality characteristics.

Wheat germ oil enrichment in broiler feed with α-lipoic acid to enhance the antioxidant potential and lipid stability of meat

BACKGROUND

Lipid peroxidation is the cause of declining the meat quality. Natural antioxidants plays a vital role in enhancing the stability and quality of meat. The supplementation of natural antioxidants in feed decreases lipid peroxidation and improves the stability of meat.

METHODS

The present research was conducted to determine the effect of α-lipoic acid, α-tocopherol and wheat germ oil on the status of antioxidants, quality and lipid stability of broiler meat. One day old male broilers were fed with different feeds containing antioxidants i.e. natural (wheat germ oil) and synthetic α-tocopherol and α-lipoic acid during the two experimental years.

RESULTS

The feed treatments have significant variation on the body weight and feed conversion ratio (FCR) while having no influence on the feed intake. The broilers fed on wheat germ oil (natural α-tocopherol) gained maximum body weight (2451.97 g & 2466.07 g) in the experimental years 2010-11 & 2011-12, respectively. The higher total phenolic contents were found in the broilers fed on wheat germ oil plus α-lipoic acid in breast (162.73±4.8 mg Gallic acid equivalent/100 g & 162.18±4.5 mg Gallic acid equivalent/100 g) and leg (149.67±3.3 mg Gallic acid equivalent/100 g & 146.07±3.2 mg Gallic acid equivalent/100 g) meat during both experimental years. Similar trend was observed for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power assay (FRAP). The production of malondialdehydes in the breast and leg meat increased with progressive increase in the time period. The deposition of α-tocopherol (AT) and α-lipoic acid (ALA) contents were found to be higher in the broilers fed on wheat germ oil plus α-lipoic acid in breast and leg meat during the both experimental years.

CONCLUSION

In conclusion, the combination of wheat germ oil and α-lipoic acid has more beneficial for stability and the quality of the broiler meat and more work should be needed in future for the bio-evaluation of this kind of functional meat in humans.

Relação vitamina E: vitamina C sobre a qualidade da carne de frangos submetidos ao estresse pré-abate

Determinou-se a melhor relação vitamina E:vitamina C em dietas para frangos de corte, visando ao melhor desempenho produtivo e à melhor qualidade da carne das aves submetidas ao estresse pré-abate. Utilizaram-se 800 pintos de corte, machos, distribuídos em delineamento inteiramente ao acaso, em esquema fatorial 2x4, com dois níveis de suplementação de vitamina E - 0 e 250mg/kg - e quatro de vitamina C - 0, 150, 300 e 450mg/kg. Aos 42 dias de idade, 12 horas ante mortem, amostras de aves de cada tratamento foram submetidas ao estresse por calor e, em seguida, pelo transporte. Foram avaliadas características de desempenho - peso vivo, consumo de ração e conversão alimentar - , bem como rendimento de carcaça e qualidade da carne de peito e coxas - perda de água, cor e pH. Os níveis de vitaminas avaliadas não influenciaram nas características de desempenho avaliadas. Houve menor rendimento de peito (34,2 vs. 34,9%) e maior pH inicial (6,3 vs. 6,1) dos cortes, para aves que sofreram estresse em relação àquelas que não foram submetidas ao estresse pré-abate.

Effects of dietary hesperidin supplementation on lamb performance and meat characteristics

An experiment was conducted to examine the effects of supplementing feed with hesperidin or α-tocopheryl acetate on lambs' growth performance, carcass and meat characteristics. Sixteen male lambs were randomly assigned to four groups. One of the groups served as control and was given a basal diet, whereas the other three groups were given the same diet further supplemented with hesperidin at 1500 mg/kg, or hesperidin at 3000 mg/kg, or α-tocopheryl acetate at 200 mg/kg. At the end of the experiment, lambs were fasted, weighed and slaughtered. After overnight chilling, samples of Longissimus thoracis muscle were taken and were used for meat quality evaluation. No significant differences were observed in final body weight, body weight gain and organ weights among the four groups. pH, color, water-holding capacity, shear force values and intramuscular fat concentration of Longissimus thoracis muscle were also not significantly influenced by the dietary treatments. Measurement of lipid oxidation values showed that hesperidin supplementation positively influenced meat antioxidant properties during refrigerated storage.

Chromium supplementation can alleviate the negative effects of heat stress on growth performance, carcass traits, and meat lipid oxidation of broiler chicks without any adverse impacts on blood constituents

This study was conducted to determine the effects of dietary supplementation with Cr nicotinate and Cr chloride and their optimum inclusion rate on performance, carcass traits, meat oxidative stability, serum metabolites, hematological parameters, and liver chromium concentration in heat-stressed broilers. A total number of 420, 1-day-old male broiler chicks were randomly assigned to seven treatments with four replicates of 15 chicks. The dietary treatments consisted of the basal diet supplemented with 0 (control), 500, 1,000, and 1,500 μg/kg Cr in the form of Cr nicotinate and Cr chloride. Chicks were raised for 6 weeks in heat stress condition (33 ± 2°C). Supplements of organic and inorganic Cr particularly at 1,500 μg/kg incorporation increased feed consumption (P < 0.05) and body mass gain of broilers (P < 0.01). Cr supplementation increased carcass yield and decreased abdominal fat (P < 0.01). Supplementation of 1,500 μg/kg Cr nicotinate (P < 0.05) enhanced liver Cr concentration. Storage time increased lipid oxidation of meat (P < 0.01). Cr decreased lipid oxidation of breast and thigh muscles over 2 (P < 0.01) or 6 (P < 0.05) days of storage time. Birds fed 1,500 μg/kg Cr nicotinate, had lower concentration of serum glucose and triglyceride at 21 days (P < 0.05). Hematological parameters tested at 21 and 42 days, were not influenced. The results suggested that dietary Cr supplementation regardless of its source have a positive effect on productive, and carcass traits, also enhances oxidative stability of refrigerated meat in broilers reared under heat stress conditions.

α-Tocopherol incorporation in mitochondria and microsomes upon supranutritional vitamin E supplementation

Vitamin E (α-tocopherol) is a major lipid-soluble chain-breaking antioxidant in humans and mammals and plays an important role in normal development and physiology. The localization of α-tocopherol within the highly unsaturated phospholipid bilayer of cell membranes provides a means of controlling lipid oxidation at the initiation site. Mitochondria are the site for major oxidative processes and are important in fat oxidation and energy production, but a side effect is leakage of reactive oxygen species. Thus, incorporation of α-tocopherol and other antioxidants into mitochondria and other cellular compartments is important in order to maintain oxidative stability of the membrane-bound lipids and prevent damage from the reactive oxygen species. Many studies regarding mitochondrial disease and dysfunction have been performed in relation to deficiency of vitamin E and other antioxidants, whereas relatively sparse information is available regarding the eventual beneficial effects of antioxidant-enriched mitochondria in terms of health and function. This may be due to the fact that only little scientific information is available concerning the effect of supranutritional supplementation with antioxidants on their incorporation into mitochondria and other cellular membranes. The purpose of this review is therefore to briefly summarize experimental data performed with dietary vitamin E treatments in relation to the deposition of α-tocopherol in mitochondria and microsomes.

The effects of dietary hesperidin supplementation on broiler performance and chicken meat characteristics

Simitzis, P. E., Symeon, G. K., Charismiadou, M. A., Ayoutanti, A. G. and Deligeorgis, S. G. 2011. The effects of dietary hesperidin supplementation on broiler performance and chicken meat characteristics. Can. J. Anim. Sci. 91: 275–282. An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin, a bioflavonoid that is an abundant and inexpensive by-product of citrus cultivation, on growth performance, carcass characteristics, breast meat quality characteristics and the oxidative stability of breast meat. Eighty 308-d-old Ross male broiler chickens were randomly assigned to four groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other three groups were given the same diets further supplemented with hesperidin at 1.5 g kg−1 (HE1), or hesperidin at 3.0 g kg−1 (HE2), or α-tocopheryl acetate at 0.2 g kg−1 (VE). At 40 d of age, broilers were fasted for 12 h, weighed and slaughtered. After overnight chilling, carcasses were trimmed for breast fillets by removing skin, bones and connective tissue. The right pectoralis major muscle was used for quality parameters estimation, whereas the left pectoralis major muscle for lipid oxidation measurements. No significant differences were observed after dietary hesperidin or α-tocopheryl acetate supplementation in final body weight (kg), body weight gain (g), feed conversion rate and internal organs weight (g). Shear values (N mm−2), intramuscular fat (%) and cooking loss (%) were also not significantly influenced by the dietary treatments. Significant differences were found concerning pH24 and color parameter values among the treatment groups. Measurement of lipid oxidation values showed that as hesperidin increased in the diet, malondialdehyde values decreased in tissue samples, suggesting that hesperidin particularly at 3 g kg−1 exerted an antioxidant effect on chicken tissues (P<0.01). However, dietary α-tocopheryl acetate supplementation at 0.2 g kg−1 of feed displayed greater antioxidant activity than hesperidin at either supplementation rate (P<0.01). In conclusion, hesperidin, an abundant component of citrus pulp, positively influences meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing to be an important additive for both the consumer and the industry.

Dietary strategies to improve nutritional value, oxidative stability, and sensory properties of poultry products

Consumers demand both safer and more nutritious food products exempt of non-natural origin preservatives or other food additives. In this frame, products with lower fat content and/or a higher ratio in unsaturated fatty acids, especially n-3 fatty acids, are desired because these lipids can help prevent the development of cardiovascular and inflammatory pathologies. The intake of meat products is of interest because they are an excellent source of vitamins and minerals. In addition, the shelf-life of meat products can be extended by the presence of natural antioxidants coming from different sources such as plant extracts. Therefore, different strategies have been studied to improve the nutritional value, oxidative stability, and sensory characteristics of meat products and eggs through different mineral and natural dietary supplements. In comparison to other strategies, dietary supplements present the advantage that first the living animals may efficiently distribute the compounds throughout the tissues and second, the dietary supplementation is safer because the resulting enriched meat products and eggs ensure tolerable amounts in humans. Poultry meats and eggs are widely consumed and their fatty acid profile and tocopherol content can be easily modified through different dietary strategies thus being excellent models to improve their nutritional value and oxidative stability.

Soybean, palm kernel, and animal-vegetable oils and vitamin E supplementation effect on lipid oxidation stability of sous vide chicken meat

There is an increasing demand in precooked chicken meat products for restaurants and catering services. Because cooked chicken meat develops lipid oxidation relatively fast, sous vide chicken meat was studied to assess its shelf-life. Six hundred Cobb x Ross broilers were fed for 6 wk with a basal corn-soybean meal diet including soybean, palm kernel, or animal-vegetable oil, each supplemented with 33 or 200 mg/kg of dl-alpha-tocopheryl acetate. Broilers were randomly assigned into 6 treatments and 4 repetitions with 25 birds each. Boneless breast or thigh muscle pieces were dissected into 5 x 5 x 5 cm cubes, vacuum-packed, cooked in water bath (until 74 degrees C internal temperature), chilled, and stored at 4 degrees C for 1, 5, 10, 25, and 40 d. For each storage day, each pouch contained 3 pieces of meat, either breast or thigh. Thiobarbituric acid reactive substances analysis, to quantify malonaldehyde (MDA) values, was conducted to estimate the lipid oxidation development. Nonheme iron values of cooked meat were analyzed. Fatty acid methyl esters analysis was performed in chicken muscle to determine its fatty acid composition. There was no interaction between dietary fat and vitamin E level in all of the variables studied except in nonheme iron. Dietary fat significantly influenced the fatty acid composition of the muscle (P < 0.01), but it did not affect the MDA values, regardless of differences in the muscle fatty acid composition between treatments. Supplementation of the high level of vitamin E significantly reduced the MDA values in both breast and thigh meat (P < 0.01). The maximum MDA values were observed at d 40 of storage in thigh and breast meat in animal-vegetable and soybean oil treatments with the low levels of vitamin E, 0.91 and 0.70 mg/kg, respectively. Nonheme iron values in thigh meat differed between treatments at 1 or 25 d of storage but not in breast meat. In conclusion, refrigerated sous vide chicken meat has a prolonged shelf-life, which is enhanced by dietary supranutritional supplementation of vitamin E.

The effects of dietary oregano oil supplementation on pig meat characteristics

The effects of different concentrations of dietary oregano essential oil supplementation on finishing pig meat characteristics were investigated in the present study. Thirty-two barrows and thirty-two gilts were divided into four equal groups. During the experimental period, which started when the animals were 5 months old and finished after 35 days, the first group was fed the control diet (group C), whereas the other three groups consumed the same diet, with the only difference that the feed was supplemented with oregano essential oil at concentrations of 0.25, 0.5 and 1 ml/kg of fed diet (groups OR1, OR2 and OR3, respectively). At the end of the experiment, pigs were fasted for 12 h, weighed and slaughtered. After overnight chilling, a 50 cm loin section was removed from the half of the carcasses (8 pigs per nutritional treatment; 4 barrows and 4 gilts) and transported to laboratory for further examination. No significant differences were observed after dietary oregano essential oil supplementation in final body weight (kg), body weight gain (g) and dressing out (%). Tenderness of longissimus muscle, expressed as shear force value, pH values at 45 min and 24 h postmortem, colour parameters and sensory attributes of eating quality were not significantly influenced by the dietary treatment. Moreover, the lipid oxidation results suggested a lack of antioxidant effect for the oregano essential oil. In conclusion, carcass and meat quality attributes were unchanged, indicating that the dietary administration of different levels of oregano essential oil did not exert any effect on pig meat parameters in the present experiment.

The incorporation of dehydrated rosemary leaves in the rations of turkeys and their impact on the oxidative stability of the produced raw and cooked meat

Thirty-six 12-week-old turkeys were distributed into six groups and were raised for 4 weeks on rations containing 0%, 0.5% or 1.0% dehydrated rosemary leaves as antioxidant in the presence of alpha-tocopheryl acetate from 10 to 300 mg/kg. Following slaughtering, breast and thigh meat samples, raw or cooked, from all six groups were collected to be refrigerated at 4 degrees C for 9 days. All stored samples were submitted to analysis for their concentration in malondialdehyde (MDA), a lipid oxidation marker, and alpha-tocopherol. The results showed that the rations containing 300 mg/kg alpha-tocopheryl acetate increased the mean alpha-tocopherol content of the breast and thigh significantly (P <0.05) compared with the respective control values. No significant (P>0.05) changes could be observed in the alpha-tocopherol content of breast and thigh of turkeys consuming rations containing up to 1% dehydrated rosemary leaves. The refrigeration of the meats led to spontaneous increase in the MDA content of the breast and thigh meat samples. Samples from turkeys fed rations containing 300 mg/kg alpha-tocopheryl acetate showed the lowest mean levels of MDA after the 9-day refrigerated period. The incorporation of rosemary in the rations led to a modest decrease in the formation of MDA in the meats compared with the respective mean control values. The combination of alpha-tocopheryl acetate and rosemary was not associated with an additional decrease in MDA formation.

Influence of different dietary doses of n-3- or n-6-rich vegetable fats and alpha-tocopheryl acetate supplementation on raw and cooked rabbit meat composition and oxidative stability

This study evaluates the effects of replacing beef tallow added to rabbit feeds (3% w/w) by different doses (0%, 1.5% and 3% w/w) of n-6- or n-3-rich vegetable fat sources (sunflower and linseed oil, respectively) and alpha-tocopheryl acetate supplementation (0 and 100 mg/kg) on the fatty acid composition, alpha-tocopherol content, and oxidation levels [assessed by analyzing thiobarbituric acid (TBA) and lipid hydroperoxide values] in rabbit meat. We also measured these parameters after cooking and refrigerated storage of cooked rabbit meat. Both dietary alpha-tocopheryl acetate supplementation and the dose and source of fat added to feeds influenced meat fatty acid composition, modifying the n-6/n-3 ratio, which was more nutritionally favorable when linseed oil was used. Furthermore, the addition of linseed oil and the supplementation with alpha-tocopheryl acetate enhanced long-chain PUFA biosynthesis. However, the addition of 3% linseed oil increased meat oxidation, and although it was reduced by dietary supplementation with alpha-tocopheryl acetate in raw meat, this reduction was not as effective after cooking. Therefore, dietary supplementation with 1.5% linseed oil plus 1.5% beef tallow and with alpha-tocopheryl acetate would be recommended to improve the nutritional quality of rabbit meat.

Effect of dietary oregano oil supplementation on lamb meat characteristics

The effect of dietary oregano essential oil supplementation on lamb meat characteristics was investigated. Eight male and eight female Chios lambs were divided into two equal groups. The first group was fed with the control diet consisting of concentrated feed and alfalfa hay, whereas the second group consumed the same diet, the only difference being that the concentrated feed was uniformly sprayed with oregano essential oil (1ml/kg). Duration of the experimental period was two months. No differences were observed after oregano essential oil supplementation in final body weight (kg), body weight gain (g) and carcass yield (%). Tenderness of longissimus thoracis muscle, expressed as sarcomere length and shear force value, was not influenced by the treatment, whereas pH and colour parameters (yellowness-redness) appeared to increase (P<0.05). Moreover, results showed that dietary incorporation of oregano essential oil exerted strong antioxidant effects retarding lipid oxidation (MDA formation) in meat during refrigerated and long-term frozen storage (P<0.001).