Dietary Α-tocopheryl Acetate Supplementation Research Articles

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 pH24and 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−1exerted an antioxidant effect on chicken tissues (P<0.01). However, dietary α-tocopheryl acetate supplementation at 0.2 g kg−1of 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.

Influence of Dietary α-Tocopheryl Acetate Supplementation on Cholesterol Oxidation in Retail Packed Chicken Meat during Refrigerated Storage

This study examined the effect of dietary alpha-tocopheryl acetate on lipid and cholesterol oxidation in retail packed chicken meat during refrigerated storage. Male broiler chicks were randomly assigned to five pens containing 30 chicks each, which was subjected to one of five dietary treatments (0, 50, 100, 200, or 400 IU of alpha-tocopheryl acetate/kg diet). Five different levels of alpha-tocopherol were supplied to the chicks from 3 to 6 weeks. After 42 d of feeding all the broilers were slaughtered, and the carcasses were packed in polyethylene bags individually, bags similar to those used in the retail trade, and stored for 12 d at 4 degrees C. Growth performance and fatty acid composition were not affected by the dietary alpha-tocopherol levels. The alpha-tocopherol content in breast and thigh muscles increased as the level of dietary alpha-tocopherol increased. The supplementation with 200 or 400 IU of alpha-tocopherol was more effective in reducing the level of lipid oxidation (P<0.05) and total cholesterol oxidation products (P<0.05). Therefore, an increase in the dietary alpha-tocopherol level from 200 to 400 IU/kg feed causes major improvements in the oxidative stability of chicken meat during refrigerated storage.

Shelf-Life Evaluation of Modified Atmosphere and Vacuum Package Fillets of Atlantic Halibut (Hippoglossus hippoglossus), Following Dietary α-Tocopheryl Acetate Supplementation

Atlantic halibut were fed 249 and 544 mg a-tocopheryl acetate per kg diet for 2 months. After slaughter, fillet portions were stored for 11 days at 2°C in MAP and vacuum packed at -20°C for 6 weeks. The diet low in vitamin E was sufficient to ensure saturation of fillet a-tocopherol. However, the higher level of dietary a-tocopheryl acetate resulted in significantly less malondialdehyde (MDA) in modified atmosphere packs (MAP) (P = 0.022) and in lower total bacterial count (TBC) in vacuum packaging (P = 0.037). Vacuum packaging resulted in significantly (P < 0.05) more moisture loss than MAP. MAP resulted in a significant increase of MDA levels and TBC (P < 0.001), while these parameters did not change in vacuum packed frozen fillets. Although color of fillets of all treatments significantly deteriorated in storage, discoloration was not very obvious.

Fillet shelf-life of Atlantic halibut Hippoglossus hippoglossus L. fed elevated levels of α -tocopheryl acetate

Fish fillet quality may be influenced by the antioxidant level in preslaughter diet. Thus, the effects of dietary α-tocopheryl acetate supplementation and feeding time on the flesh quality of farmed Atlantic halibut Hippoglossus hippoglossus L. were investigated. Halibut of mean initial weight of 312 ± 12.3 g were divided into two groups and fed commercial diets, supplemented with different levels of α-tocopheryl acetate at the dietary inclusion levels of 189 and 613 mg kg−1 diet. Fish were sampled after 6,9,12 and 24 weeks. Over the experimental period, they reached a final mean weight of 1320 ± 108.4 g. Tissue α-tocopherol of fillet and liver was significantly affected by the levels of α-tocopheryl acetate given with the diets (P < 0.001). In storage on ice, fillets of fish fed the diets high in α-tocopheryl acetate exhibited significantly lower (P < 0.001) levels of lipid oxidation. The colour of fillets in all groups deteriorated slightly, but diet did not affect this process. Halibut fed the supplemented diets for longer periods were better protected against lipid oxidation (P < 0.001) and colour deterioration (P < 0.01) than those fed for shorter periods. However, after 9 days of storage, lipid oxidation levels were still extremely low [< 0.6 µg malondialdehyde (MDA) g−1 fillet], even in fillets of fish fed the low α-tocopheryl acetate diet for a short period preslaughter. Different slaughtering methods tested at the end of the trial showed that percussive stunning can delay the onset of rigor mortis by 8–12 h compared with bleeding of the fish. These results suggest that halibut fillets have enhanced shelf-life stability even at low doses of dietary α-tocopheryl acetate, and that other factors in the antioxidant defence mechanisms of the species might play a major role in the prevention of lipid oxidation.

Effect of supranutritional level of dietary α-tocopheryl acetate and selenium on rabbit semen

This research examined the effects of dietary α-tocopheryl acetate (50 or 200mg/kg diet) and selenium (Se, 0 or 0.5ppm) supplementation on motion characteristics, oxidative stability and fertilizing ability of rabbit spermatozoa, fresh and stored for 24h at 5°C. The higher amount of dietary α-tocopheryl acetate increased the level of Vitamin E in the fresh semen (1.75mmol/l versus 0.95mmol/l) and its oxidative stability (thiobarbituric acid reactive substances—TBARS 12.44nmol malondialdehyde/108sperm versus 21.4nmol malondialdehyde/108sperm). Dietary Se increased gluthatione peroxidase activity (GPx) in erythrocytes (285U/g Hb versus 207U/g Hb), seminal plasma (270U/l versus 190U/l) and spermatozoa (1338mU/109sperm versus 1103mU/109sperm), whereas it did not show any effect on α-tocopherol level and TBARS. No synergy between Vitamin E and Se was shown. Storage for 24h at 5°C increased the TBARS level in all the experimental groups. Neither live and acrosome reacted spermatozoa, nor kinetic parameters, nor fertility rate were modified by dietary supplementation.

Effect of dietary linseed oil on pig hepatic tissue fatty acid composition and susceptibility to lipid peroxidation

The effect of linseed oil and α-tocopheryl acetate on fatty acid composition and susceptibility to oxidation in pig liver was studied. The α-tocopherol content of liver from pigs fed diets supplemented with α-tocopheryl acetate (200 mg/kg feed) was significantly greater ( P < 0.001) than that of liver from pigs receiving a basal diet of 20 mg/kg feed. The concentration of C12:0, C16:0, C18:0 and total saturated fatty acids was higher in liver lipids from pigs fed the control diet than in the other groups ( P < 0.05). No effect of dietary linseed administration was observed on monounsaturated fatty acid concentration. Adding linseed oil to pig diets either as the only source of dietary fat or in combination with olive oil produced a higher ( P < 0.0001) C18:3 (n-3), C20:4 (n-3) and C22:5 (n-3) concentration in liver lipids. However, no significant effect of dietary treatment was observed on C20:5 (n-3) and C22:6 (n-3). For C20:4 (n-3), a marked effect of dietary linseed concentration was observed, while for C22:5 (n-3) there were no differences between pigs receiving a moderate or a high dietary level of linseed oil. Oxidation was higher in hepatic tissue homogenates from pigs fed linseed oil-enriched diets ( P < 0.05), but 200 mg/kg dietary α-tocopheryl acetate supplementation reduced oxidation, reaching similar values to those of the control group.

Slaughtering method and dietary α -tocopheryl acetate supplementation affect rigor mortis and fillet shelf-life of turbot Scophthalmus maximus L.

The effects of dietary α-tocopheryl acetate supplementation and different slaughtering methods were investigated on the flesh quality of farmed market-size turbot Scophthalmus maximus (L). Turbot were divided into three groups and fed commercial diets, supplemented with different levels of α-tocopheryl acetate at the following dietary inclusion levels: 72 (100), 547 (500), 969 (1000) (mg of α-tocopheryl acetate kg−1 diet, analytical values with diet codes in brackets). After 5 months, fish (mean weight 1056 ± 19.7 g) from each dietary treatment were sampled, applying three different slaughtering methods: (A) bleeding in ice water; (B) thermal shock, no bleeding; (C) percussion followed by bleeding in ice water. The time course of rigor mortis was evaluated, using pH, rigor index and mechanical compression tests. The results showed that the three parameters corresponded very well. Percussive stunning resulted in higher initial post-mortem pH (P < 0.01) and a significantly delayed onset of rigor mortis (P < 0.05). Diet significantly affected shelf-life, with fillets from fish fed diets 500 and 1000 having lower TBARS (thiobarbituric acid reactive substances) numbers from day 2 (P < 0.001) and less colour deterioration from day 7 of storage on ice onwards (P < 0.05). These results suggest that an increase in dietary α-tocopheryl acetate before slaughter as well as careful selection of the slaughtering method may greatly enhance the flesh quality of market-size turbot.

The effect of dietary oregano essential oil on lipid oxidation in raw and cooked chicken during refrigerated storage

The antioxidative effect of dietary supplementation with oregano essential oil on susceptibility of raw and cooked breast and thigh muscle meat of chickens to lipid oxidation during refrigerated storage for 9 days was investigated. Day-old chickens ( n=80) were randomly divided into four groups and fed a basal diet containing 30 mg α-tocopheryl acetate kg −1 feed as control, or basal diet plus 200 mg α-tocopheryl acetate kg −1 feed, or basal diet plus 50 or 100 mg oregano essential oil kg −1 for 38 days prior to slaughter. Lipid oxidation was assessed by monitoring malondialdehyde (MDA) formation in raw and cooked meat during 0, 3, 6 and 9 days of refrigerated storage, using the thiobarbituric acid (TBA) assay and third-order derivative spectrophotometry. Results showed that dietary oregano essential oil supplementation exerted antioxidative effects, the supplementation being most effective in retarding lipid oxidation in stored raw and cooked meat at the 100 mg oregano essential oil kg −1 feed. However, dietary α-tocopheryl acetate supplementation at 200 mg kg −1 feed displayed greater antioxidant activity than oregano treatments. Thigh muscle was more susceptible to oxidation compared to breast muscle in all treatments, although the former tissues contained α-tocopherol at markedly higher levels.

Dose-response effect of dietary vitamin E concentration on meat quality characteristics in light-weight lambs

AbstractThe research was carried out to evaluate the effect of different dietary α-tocopheryl acetate (DTA) concentrations in light-weight lambs on muscle α-tocopherol accumulation and on quality characteristics of stored meats. Thirty-two Manchego lambs were randomly distributed to four groups and given diets containing four levels of DTA (20, 270, 520 and 1020 mg/kg diet) for 6 weeks. Lambs were slaughtered at live weights ranging from 23·5 to 26·4 kg. A linear (P &lt; 0·001) and quadratic (P &lt; 0·001) effect of dietary supplementation level was observed on muscular α-tocopherol concentration, which fitted the following equation: mg muscle α-tocopherol per kg muscle = 1·78(s.e. 0·18) + 7·08 (s.e.0·89)(1 - e00012DTA)) (P &lt; 0·001, R2 = 0·99). There was a linear effect (P &lt; 0·001) of muscle vitamin E concentration on thiobarbituric acid reactive substance on day 0 of storage, but a linear plus quadratic effect (P &lt; 0·001) on days 3, 6 and 9. Broken line analysis of data at day 9 of storage indicated a target muscle α-tocopherol concentration of 5·4 mg/kg. Evolution of surface redness of lamb chops also showed a linear and quadratic effect of dietary treatment on days 3 and 6 of storage, but only a linear effect on day 9. Broken line analysis of data at 3 and 6 days indicated a target α-tocopherol concentration in the range 5·3 to 5·6 mg/kg muscle for optimum red colour stability. Surface luminosity showed no effect of dietary treatment at days 0, 3 and 6 of storage but a linear (P &lt; 0·01) plus quadratic (P &lt; 0·05) effect on day 9 of storage. Broken line analysis at this point indicated a target muscle α-tocopherol concentration of 3·2 mg/kg. It is concluded that the effectiveness of dietary α-tocopheryl acetate supplementation depends on the meat quality attribute assessed. A significant positive effect for lipid oxidation can be reached even at the lower supplementation level utilized in this experiment (270 mg/kg diet). However, considering the protecting effect at different storage times and particularly the effect on meat surface redness, the optimum level would be in the range 5·3 to 5·6 mg/kg muscle, which correspond to a dietary inclusion of 550 to 625 mg α-tocopheryl acetate/kg diet.

Distribution of α-tocopherol in beef muscles following dietary α-tocopheryl acetate supplementation

The objective of this study was to determine the effect of dietary vitamin E supplementation on the distribution and concentration of α-tocopherol in beef muscles. Crossbred cattle ( n=8) were selected and divided into two groups and fed diets containing 20 (basal) and 3000 mg (supplemented) α-tocopheryl acetate/head/day for 135 days prior to slaughter. Carcasses were split centrally and chilled at 4°C for 10 days. Muscles ( n=16) were identified and removed from the left side of each animal and stored at −20°C until required. Mean α-tocopherol levels in muscles were significantly ( P<0.05) higher in all supplemented muscles with the exception of m. infraspinatis and m. deltoidous compared to controls. Mean α-tocopherol levels in muscles from the supplemented group decreased in the order m. supraspinatis > m. psoas major > m. trapezius > m. gluteus medius > m. triceps caput brachii lumborum > m. rhomboidous > m. seratus ventralis > m. gluteobiceps > m. semitendinosus > m. semimembranosus > m. infraspinatis > m. subscapularis > m. tricepscaputbrachiilaterale > m. deltoidous > m. longissimus thorasis > m. longissimus lumborum. Significant ( P<0.05) differences in α-tocopherol distribution within muscles were observed for supplemented m. psoas major and control m. seratus ventralis (highest levels in posterior ends and lowest in anterior ends) only. However, trends showed definite distribution patterns for other muscles. Levels of α-tocopherol were found to be highest in oxidative muscles ( m. psoas major and m. gluteus medius) and lowest in glycolytic muscles ( m. longissimus thoracis and m. longissimus lumborum) while moderate levels of α-tocopherol occurred in intermediate muscles ( m. semimembranosus).

Reduced nitrite levels and dietary α-tocopheryl acetate supplementation: effects on the colour and oxidative stability of cooked hams

The objective of the present study was to determine the effects of dietary vitamin E supplementation and reduced nitrite levels on the colour stability of cooked hams. Large white × Landrace pigs (male n=6, female n=6) were each subdivided into two groups ( n=3) and fed an α-tocopheryl acetate supplemented diet (1000 mg/kg feed) and a basal diet (10 mg/kg feed) for a period of 10 weeks . M. semitendinosus were removed from each pig, divided into light and dark pigmented fractions, vacuum packed and stored at 4°C for 24 h. Muscles were cured with input nitrite levels of 25 and 100 mg/kg meat and were tumbled and massaged for 17 h. Samples were cooked, sliced and overwrapped in a high oxygen permeable film for a storage period of 10 days. Surface colour of hams was measured and expressed as Hunter ‘ a’ values. Concentrations of α-tocopherol were significantly ( P<0.001) greater in supplemented muscles compared to basal muscles for both male and female pigs. Hams manufactured from male and female supplemented pigs resulted in significantly ( P<0.001) higher Hunter ‘ a’ values than hams manufactured from male and female pigs receiving the basal diet. Muscles cured with 100 mg nitrite/kg meat formed products with significantly ( P<0.001) higher ‘ a’ values than those cured with the lower (25 mg/kg meat) nitrite level. Hams manufactured from supplemented muscles, treated with 25 mg nitrite/kg meat showed significantly ( P<0.05) higher Hunter ‘ a’ values than hams manufactured from basal muscles, treated with 100 mg nitrite/kg meat. Hams manufactured from female porcine muscles had significantly ( P<0.001) higher ‘ a’ values than hams from male muscles during the 10 days of simulated retail display. No such gender differences were observed for TBARS values.

The effects of dietary α-tocopheryl acetate supplementation and modified atmosphere packaging (MAP) on the quality of lamb patties

The effects of dietary α-tocopheryl acetate supplementation and/or packaging on the quality of lamb patties were investigated. Ewes ( n=12) were selected and scanned to assess pregnancy. They were divided into two groups ( n=6). The control group was fed a non-supplemented diet of 20 mg α-tocopheryl acetate/kg feed/day for 9 weeks ante-parturition and 3 weeks post-parturition. The lambs were weaned at 3 weeks and fed either the non-supplemented or supplemented diet for 10 weeks prior to slaughter. The M. longissimus dorsi from each carcass from each dietary group was stored at −20°C for 7 months. Patties were formed from supplemented or control minced m. longissimus dorsi and held in either modified atmosphere packs (MAP) under atmospheres of 70:30, 80:20 or 90:10 CO 2:O 2, under vacuum or in overwrapped trays. All packs were held under refrigerated (4°C, 616 lux) display for a period of 10 days. Patties were assessed for oxidative and colour stability on days 0, 2, 4, 6, 8 and 10. With each type of pack, dietary α-tocopheryl acetate supplementation significantly increased oxidative and colour stability compared to control patties. As oxygen concentrations increased in MAP packs, colour stability was enhanced but the rate of lipid oxidation increased. Vacuum packaged patties had significantly ( P<0.05) higher Hunter ‘ a' values, lower proportions of metmyoglobin and lower TBARS numbers than those held under all other forms of packaging. Aerobically packaged patties had lower Hunter ‘ a' values, higher proportions of metmyoglobin and lower TBARS numbers compared to MAP patties.

Influence of dietary α-tocopheryl acetate supplementation of pigs on oxidative deterioration and weight loss in sliced dry-cured ham

The effect of feeding high levels of α-tocopherol to pigs on the susceptibility to oxidative deterioration and weight loss in dry cured hams was investigated. The α-tocopherol concentration in thigh muscle from pigs fed the basal and the supplemented diet (200 mg kg −1 α-tocopheryl acetate) in unprocessed thighs was 8.69 and 16.87, μg g −1 dry matter, not including ash, respectively ( p-value=0.015), while the concentration was 6.65 and 14.28 μg g −1, respectively, in the final products ( p-value=0.011). Hams from pigs fed the basal diet oxidized more during storage ( p-value=0.015) as measured by formation in thiobarbituric acid reactive substances and had a higher rate of weight loss ( p-value=0.0001). The total loss in red color after 4 days of storage was similar in all treatments. However, the rate of discoloration was more pronounced during the first 2 days of storage in hams from pigs fed the basal diet ( p-value=0.016). This result indicates that high dietary level of α-tocopheryl acetate to pigs increases the oxidative stability in dry cured hams manufactured on the basis of such pigs.

Catalase addition prevented a decrease in sperm motility of cryopreserved bovine semen exposed to reactive oxygen species

This research examined the effects of dietary α-tocopheryl acetate (50 or 200 mg/kg diet) and selenium (Se, 0 or 0.5 ppm) supplementation on motion characteristics, oxidative stability and fertilizing ability of rabbit spermatozoa, fresh and stored for 24 h at 5 °C. The higher amount of dietary α-tocopheryl acetate increased the level of Vitamin E in the fresh semen (1.75 mmol/l versus 0.95 mmol/l) and its oxidative stability (thiobarbituric acid reactive substances—TBARS 12.44 nmol malondialdehyde/108 sperm versus 21.4 nmol malondialdehyde/108 sperm). Dietary Se increased gluthatione peroxidase activity (GPx) in erythrocytes (285 U/g Hb versus 207 U/g Hb), seminal plasma (270 U/l versus 190 U/l) and spermatozoa (1338 mU/109 sperm versus 1103 mU/109 sperm), whereas it did not show any effect on α-tocopherol level and TBARS. No synergy between Vitamin E and Se was shown. Storage for 24 h at 5 °C increased the TBARS level in all the experimental groups. Neither live and acrosome reacted spermatozoa, nor kinetic parameters, nor fertility rate were modified by dietary supplementation.

Assessment of α-tocopheryl acetate supplementation, addition of salt and packaging on the oxidative stability of raw turkey meat

1. One-day-old turkey poults (n=14) were randomised into 2 groups (n=7) and fed diets containing 20 (E20) and 600 (E600) mg all-rac-α-tocopheryl acetate/kg food for 21 weeks prior to slaughter. Two batches were formed from E20 meat (E20) and E20 plus 10 g salt/kg (E20S). Two similar batches were formed from E600 meat (E600) and E600 plus 10 g salt/kg (E600S). 2. The effects of α-tocopheryl acetate supplementation and salt addition on the oxidative stability of raw turkey patties was investigated during aerobic and vacuum-packaged refrigerated (4°C) storage. 3. Dietary α-tocopheryl acetate supplementation reduced TBARS (thiobarbituric acid reacting substances) numbers for raw overwrapped and vacuum-packaged turkey leg and breast patties. 4. Dietary α-tocopheryl acetate had the greatest influence on TBARS numbers for raw overwrapped turkey leg patties. 5. The addition of 10 g salt/kg increased TBARS numbers for overwrapped and vacuum-packaged turkey leg and breast patties. 6. Vacuum-packaged patties remained more oxidatively stable than similarly treated overwrapped patties throughout the experimental period.

Effect of dietary α-tocopheryl acetate supplementation on α-tocopherol distribution in raw turkey muscles and its effect on the storage stability of cooked turkey meat

Day-old turkey chicks ( n = 99) were divided at random into three groups ( n = 33) and fed diets containing 20 (E20), 300 (E300) and 600 (E600) mg all-rac-α-tocopheryl acetate per kg feed per day for 21 weeks prior to slaughter. After slaughter, breasts and legs were removed and examined for α-tocopherol content. Breast muscle from birds fed the three diets was oven cooked, cooled, sliced and overwrapped. The oxidative and colour stability of the slices was examined. Mean α-tocopherol levels in turkey muscle were significantly ( p < 0.05) higher in the E300 and E600 groups compared to the control group fed the E20 diet. α-Tocopherol levels in the E300 and E600 groups showed that concentrations in leg muscle were significantly ( p <0.05) higher than in breast muscle. α-Tocopherol levels in leg and breast muscles from birds fed E20 and E600 diets decreased significantly (p < 0.05) during 12 months of frozen (−20 °C) storage. TBARS numbers for breast slices from all three dietary groups, cooked both 24 hr after slaughter and following frozen (−20 °C × 11 months) storage, increased during refrigerated (4 °C) display for 10 days. TBARS numbers for slices produced from meat previously held in frozen storage increased more rapidly than those for meat cooked following slaughter. In both cases, E300 and E600 diets significantly ( p < 0.05) suppressed lipid oxidation compared to E20 samples. In general, Hunter a values for meat slices from turkeys fed the E300 and E600 diets were higher than those for meat slices from turkeys fed the E20 diet.

Effect of Dietary Vitamin E on the Oxidative Stability of Raw and Cooked Rabbit Meat

The effect of dietary α-tocopheryl acetate supplementation (200 mg/kg diet) on plasma and muscle levels of α-tocopherol and the oxidative stability of raw and cooked rabbit meat was determined. Two groups of 20 male hybrid rabbits were fed the experimental diets from 35 to 80 days of age. Feed intake, live weight, feed efficiency and qualitative traits of the carcass and meat were recorded. The α-tocopherol levels in plasma and muscle were significantly higher ( p≤0·01) in the supplemented group, which also showed an increase in oxidative stability in both raw and cooked meat. The higher α-tocopherol level improved the physical traits of the meat, significantly reducing shear value and increasing water-holding capacity; n-3 fatty acids in raw and cooked meat increased ( p≤0·05) and the thrombogenic index decreased ( p≤0·05). Dietary vitamin E did not influence weight gain, feed intake and dressing yield.

Effect of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken

The effects of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken during refrigerated storage were studied. Minced breast and thigh meat from broilers fed diets supplemented with 100, 200 or 400 mg α-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0kGy. Cooked irradiated and unirradiated meat was stored at 4 °C for 5 days. α-Tocopherol concentrations increased with increasing dietary supplementation. Concentrations decreased during storage, but retention was not affected by irradiation. Lipid stability was determined by measuring the formation of thiobarbituric acid-reacting substances (TBARS) and cholesterol oxidation products (COPs) during storage. TBARS and COPs increased during storage and were reduced by increasing levels of dietary α-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg α-tocopheryl acetate/kg feed. Irradiation tended to increase COPs during storage, although no consistent effects were observed. In general supplementation with over 400 mg α-tocopheryl acetate/kg feed may be required to control cholesterol oxidation in minced chicken. The results suggest that, overall, irradiation had little effect on lipid stability in α-tocopherol-supplemented meat following cooking and storage.

Cholesterol oxides in processed chicken muscle as influenced by dietary α-tocopherol supplementation

The effect of dietary α-tocopheryl acetate supplementation on the formation of cholesterol oxidation products (COPs) in chicken muscle during storage was investigated. Broiler chicks (Cobb 500 strain) were fed diets supplemented with 20, 200 or 800 mg α-tocopheryl acetate kg −1 feed. Cooked breast and thigh muscle patties were prepared and stored at 4 °C for up to 12 days. Dietary supplementation significantly ( p < 0.05) increased α-tocophenol concentrations in cooked muscle and decreased thiobarbituric acid-reacting substances (TBARS) during storage. COPs increased during storage. Total COPs ranged from 0.17–3.48 and 2.49–5.79 μg g −1 in breast and thigh meat, respectively. TBARS and total COPs were linearly correlated in breast ( r = 0.68, p < 0.001,) and thigh patties ( r = 0.75, p < 0.05). Dietary α-tocopheryl acetate supplementation significantly ( p < 0.05) reduced the formation of COPs during storage. Total COPs formed after 12 days were reduced by 42 and 75% in breast, and 50 and 72% in thigh, at supplementation levels of 200 and 800 mg kg −1 feed, respectively.

Effects of dietary α-tocopheryl acetate supplementation on α-tocopherol deposition in porcine m. psoas major and m. longissimus dorsi and on drip loss, colour stability and oxidative stability of pork meat

The effect of feeding supra-nutritional levels of α-tocopheryl acetate on its deposition in two porcine muscles of different metabolic rates ( m. longissimus dorsi and m. psoas major) and the effect on meat quality (lipid oxidation, colour stability and drip loss) was studied. Pigs were fed a standard diet supplemented with three levels: 100, 200 and 700 mg/kg of α-tocopheryl acetate from the time of weaning to slaughter at 90kg live weight. Muscle α-tocopherol levels were linearly related to the logarithm of dietary α-tocopheryl acetate supplementation and the linear relationship was estimated for the two muscles. The levels of α-tocopherol in the two muscles differed by a parallel displacement with consistently higher α-tocopherol levels in m. psoas major compared to m. longissimus dorsi. Dietary α-tocopheryl acetate supplementation significantly reduced lipid oxidation as measured by thiobarbituric acid reactive substances (TBARS) in both raw and cooked meat during storage at 4 °C for 6 days. Drip loss and colour stability of raw muscles were not affected by dietary α-tocopheryl acetate levels, 100mg α-tocopheryl acetate/ kg feed resulted in sufficient α-tocopherol levels in muscles to ensure minimum drip loss and optimum colour stability.