Fat accumulation, fatty acids and melting point changes in broiler chick abdominal fat as affected by time of dietary fat feeding and slaughter age.

1. This work aims to quantify changes in fatty acid profile, melting point, abdominal fat accumulation and 2-thiobarbituric acid-reactive substances production depending on dietary fat source and age at slaughter, and to estimate the optimal date for the change from an unsaturated fat to a saturated fat diet or vice versa. 2. Treatments established were (1) birds fed 8% tallow from 21 to 49 d (TTT); (2) birds fed 8% tallow from 21 to 37 d and 8% sunflower oil from d 38 to 49 (TSS); (3) birds fed 8% sunflower oil from 21 to 37 d and 8% tallow from d 38 to 49 (STT); (4) birds fed 8% sunflower oil from 21 to 41 d and 8% tallow from d 42 to 49 (SST); (5) birds fed 8% sunflower oil from 21 to 49 d (SSS). Birds from each group were slaughtered on d 21, 29, 38, 40, 42, 44, 46 and 49. 3. The polyunsaturated fatty acids (PUFAs) proportion in the SSS group reached maximum values at d 40 and fitted a quadratic response. This group also showed a decrease in saturated fatty acids (SATs) and monounsaturated fatty acids (MUFAs) of lower intensity than the PUFA increase. The highest synthesis of SAT + MUFA was found in the SSS and TSS groups, whereas these had the lowest body-to-dietary PUFA ratio. 4. A high and quadratic increase in the MUFA proportion was observed during the first 10 d of feeding with the tallow-enriched diet at the expenses of the proportion of PUFA that quadratically decreased (minimum values at d 38). 5. Lipogenic and desaturation capacity decreased with age. 6. The TSS group increased tissue PUFA content faster that the SST group decreased PUFA content after the change in diet which indicates that the earlier feeding has to be taken into consideration for obtaining higher or lower changes in quality parameters. 7. The melting point of the SSS group showed a lower response to the dietary treatment in the initial period when compared to the TTT treatment. 8. The TTT, STT, SST and TSS groups showed similar fat accumulation, and changes in lipid oxidation were related to the day of dietary sunflower oil supplementation. 9. Based on the results, it would be possible to determine the most appropriate dietary programme and optimum slaughter age to obtain chicken meat with the desired quality characteristics.

Ironing Out the Unconventional Mechanisms of Iron Acquisition and Gene Regulation in Chlamydia.

The obligate intracellular pathogen Chlamydia trachomatis, along with its close species relatives, is known to be strictly dependent upon the availability of iron. Deprivation of iron in vitro induces an aberrant morphological phenotype termed "persistence." This persistent phenotype develops in response to various immunological and nutritional insults and may contribute to the development of sub-acute Chlamydia-associated chronic diseases in susceptible populations. Given the importance of iron to Chlamydia, relatively little is understood about its acquisition and its role in gene regulation in comparison to other iron-dependent bacteria. Analysis of the genome sequences of a variety of chlamydial species hinted at the involvement of unconventional mechanisms, being that Chlamydia lack many conventional systems of iron homeostasis that are highly conserved in other bacteria. Herein we detail past and current research regarding chlamydial iron biology in an attempt to provide context to the rapid progress of the field in recent years. We aim to highlight recent discoveries and innovations that illuminate the strategies involved in chlamydial iron homeostasis, including the vesicular mode of acquiring iron from the intracellular environment, and the identification of a putative iron-dependent transcriptional regulator that is synthesized as a fusion with a ABC-type transporter subunit. These recent findings, along with the noted absence of iron-related homologs, indicate that Chlamydia have evolved atypical approaches to the problem of iron homeostasis, reinvigorating research into the iron biology of this pathogen.

Addition of exogenous enzymes to diets containing grape pomace: Effects on intestinal utilization of catechins and antioxidant status of chickens.

Grape pomace (GP) is a rich source of polyphenols with antioxidant capacity. An experiment was conducted to study the effect of GP phenolic compounds included at 5 and 10%, and the addition (individually or combined) of hydrolyzing enzymes (carbohydrase enzyme complex and tannase at 500ppm) on intestinal utilization of catechins and antioxidant status in broiler chickens. A diet supplemented with 200ppm of α-tocopheryl acetate was also used. Our findings demonstrate the capacity of chickens to digest the monomeric (catechin, epicatechin, gallic acid, and epicatechin-O-gallate) and dimeric (procyanidin B1 and procyanidin B2) catechins present in grape pomace. The addition of enzymes (mainly tannase) hydrolyzed the polymeric structures into smaller catechins, but also promoted a lower digestibility of the monomeric and dimeric catechins suggesting that polymeric structures might favour the intestinal utilization of these catechins. The intestinal accumulation of phenolic compounds generated with tannase and with 10% GP reversed the antimicrobial effect against Clostridium perfringens observed with 5% of GP. Grape pomace improved the antioxidant status of the bird, increasing the α-tocopherol and reducing the iron content on plasma, not affecting the plasma gluthatione. Enzymes modified the intestinal utilization of catechins but not additional protective effect was detected on any of the parameters analyzed to evaluate the antioxidant status.

Effect of dietary organic selenium on muscle proteolytic activity and water-holding capacity in pork.

This study evaluates the effect of dietary selenium (Se) supplementation source (organic, Se-enriched yeast; SY vs. inorganic, sodium selenite; SS), dose (0.2: L vs. 0.4: H mg/kg) and the combination of Se and vitamin E (VITE+SS) for 26days on drip loss, TBARS, colour changes, myofibrillar protein pattern and proteolysis in pork. The lowest water losses were observed in the SY-H group when compared to the others. SY-H and VITE+SS groups presented lower myofibrillar protein hydrolysis/oxidation. VITE+SS supplementation also resulted in higher PRO, TRP and PHE content at days 2 and 7, whereas the SY group showed increased GLY and CAR and tended to have higher TAU and ANS at day 2. The myofibrillar fragmentation index was not modified by the dietary treatment; however, at day 8, it tended to be higher in groups supplemented with SeY and VITE+SS. The results of the present study might indicate a possible relation between muscle proteolysis and water loss.

Long term vitamin A restriction improves meat quality parameters and modifies gene expression in Iberian pigs.

Vitamin A is a key regulator of gene expression, influencing adipogenesis and lipid metabolism in animal tissues. This experiment was conducted to assess the effect of dietary vitamin A level and administration time on productive traits, intramuscular fat (IMF) content in ham muscles, tissue fatty acid composition, and expression of a panel of adipogenic and lipogenic candidate genes in Iberian pigs. Sixty piglets of 16.3 kg (SD = 2.5 kg) live weight (LW) were either fed a vitamin A-enriched diet (10,000 IU vitamin A/kg; CONTROL, n = 20) or a diet without supplemented vitamin A, applied from 16.3 kg (SD = 2.5 kg; early restriction group, ER, n = 20) or from an average weight of 35.8 kg (SD = 3.1 kg; late restriction group, LR, n = 20). Two slaughters were performed when pigs reached the averaged weights of 101.4 (SD = 4.1 kg) and 157.9 kg LW (SD = 7 kg) and samples from liver, heart, and backfat were obtained in both sacrifice times. In addition, ham subcutaneous fat and Semimembranosus (SM) and Biceps Femoris (BF) muscles were sampled at the last sacrifice. Dietary vitamin A level produced no effect on carcass traits in any of the harvests, while a small effect was observed on fatty acid composition in backfat at 101.4 kg LW. However, at 157.9 kg LW, the ER and LR groups showed higher MUFA content and lower SFA content in backfat, ham fat, and IMF (P < 0.01). In IMF, a decrease in n-6/n-3 PUFA ratio was observed in the restricted groups (P < 0.005). Intramuscular fat content in SM muscle was greater (P < 0.05) in the ER group than in the CONTROL and LR groups, while no difference was detected in BF muscle. Little effect of dietary vitamin A was observed in liver. Regarding changes in gene expression, ACSL4, CEBPB, and IGF1 genes were upregulated (P < 0.0001, P < 0.0001, and P < 0.05, respectively) in the ER group in hepatic tissue, whereas CRABPII and SCD genes were upregulated (P < 0.05) in the same group in adipose tissue. On the other hand, was downregulated ( < 0.05) in the ER group in adipose tissue. Results found in this experiment show that long-term restriction of dietary vitamin A has a positive effect on nutritional and sensorial parameters of ham meat. Moreover, gene expression results were consistent with the vitamin A transcriptional regulation of adipogenesis and lipogenesis and with the changes observed in meat and fat composition.

Effect of micellized natural (D-α-tocopherol) vs. synthetic (DL-α-tocopheryl acetate) vitamin E supplementation given to turkeys on oxidative status and breast meat quality characteristics.

This study evaluates the effect of vitamin E supplementation source (micellized natural vs. the synthetic form) and dosage (40, 80, or 120 mg/kg) on α-tocopherol concentration in plasma and muscle, antioxidant capacity, and breast meat quality in turkeys. Three hundred female turkeys were randomly selected at an average live weight 63.2 g±0.5 and distributed into 7 groups. One group (control) was fed a standard diet without vitamin E supplementation and the other 6 were given mixed diets supplemented with the natural (d-α-tocopherol) or synthetic (dl-α-tocopheryl acetate) form of vitamin E in 3 dosages (40, 80, or 120 mg/kg). Following 11 wk feeding, results showed that performance parameters were not modified either by source or dosage of vitamin E supplementation to the turkeys. Plasma and muscle α-tocopherol at d 9 of refrigerated storage were higher when turkeys were supplemented with the natural form at higher doses. Losses in the concentration of α-tocopherol in meat between the beginning and the end of the 9 d refrigerated storage were greater in the groups supplemented with the synthetic form of vitamin E compared to those receiving the natural supplementation. The relationship between plasma α-tocopherol and the Trolox equivalent antioxidant capacity followed a different trend depending on the vitamin E source. Intramuscular fat was not significantly affected by the vitamin E source supplementation; however the slope of the linear regression equation was lower for the natural form than for the synthetic form. Turkeys given the natural form had higher C18:1n-9 but lower C15:1, C17:1, C20:5n-3, and C22:6n-3 in breast muscle. Meat samples from turkeys supplemented with natural vitamin E had higher deoxymyoglobin at d 3, 6, and 9 and lower metmyoglobin at d 9 of refrigerated storage than those receiving the synthetic form. Dietary supplementation with medium doses (80 mg/kg) micellized d-α-tocopherol is an interesting feeding strategy for ensuring antioxidant status and improving meat quality.

Impedance spectroscopy assisted by magnetic nanoparticles as a potential biosensor principle for breast cancer cells in suspension.

Breast cancer (BC) is the leading cause of cancer death in women worldwide, with a higher mortality reported in undeveloped countries. Ideal adjuvant therapeutic strategies require the continuous monitoring of patients by regular blood tests to detect circulating cancer cells, in order to determine whether additional treatment is necessary to prevent cancer dissemination. This circumstance requires a non-complex design of tumor cell biosensor in whole blood with feasibility for use in poor regions. In this work we have evaluated an inexpensive and simple technique of relative bioimpedance measurement, assisted by magnetic nanoparticles, as a potential biosensor of BC cells in suspension. Measurements represent the relative impedance changes caused by the magnetic holding of an interphase of tumor cells versus a homogenous condition in the frequency range of 10-100 kHz. The results indicate that use of a magnet to separate tumor cells in suspension, coupled to magnetic nanoparticles, is a feasible technique to fix an interphase of tumor cells in close proximity to gold electrodes. Relative impedance changes were shown to have potential value as a biosensor method for BC cells in whole blood, at frequencies around 20 kHz. Additional studies are warranted with respect to electrode design and sensitivity at micro-scale levels, according to the proposed technique.

Reproductive long-term effects, endocrine response and fatty acid profile of rabbit does fed diets supplemented with n-3 fatty acids.

The effect of a diet enriched with polyunsaturated n-3 fatty acids (PUFA) on endocrine, reproductive, and productive responses of rabbit females and the litters has been studied. Nulliparous does (n=125) were fed ad libitum from rearing to second weaning two diets supplemented with different fat sources: 7.5g/kg lard for the control diet (group C; n=63) or 15g/kg of a commercial supplement containing a 50% ether extract and 35% of total fatty acids (FAs) as PUFA n-3 (Group P; n=62). Dietary treatments did not affect apparent digestibility coefficients of nutrients, or reproductive variables of does including milk production, mortality and average daily gain of kits over two lactations. However, on Day 5 and 7 post-induction of ovulation, progesterone of Group P tended to increase to a greater extent than in does of Group C. Total PUFAs, n-6 and n-3 and eicosapentanoic (EPA) contents were greater in adipose tissues of does in Group P than in Group C. Docosapentaenoic acid (DPA), EPA, and docosahexaenoic acid (DHA) concentrations were greater in peri-ovarian than in scapular fat with abdominal fat being intermediate in concentration. In PUFA supplemented does, kit mortality at the second parturition tended to be less than in control does. Also, kits born to does of the PUFA-supplemented group weighed more and were of greater length than from does of control group. In conclusion, effectiveness of dietary intervention on reproductive and performance response is greater in the second parity, which suggests an accumulative long-term beneficial effect of n-3 FA supplementation in reproductive rabbit does.

Effects of oral micellized natural vitamin E (D-α-tocopherol) v. synthetic vitamin E (DL-α-tocopherol) in feed on α-tocopherol levels, stereoisomer distribution, oxidative stress and the immune response in piglets.

This study evaluated the strategy of supplementing oral micellized natural vitamin E (D-α-tocopherol) to either piglets and/or sows on α-tocopherol concentrations in piglets serum and tissues after weaning. One first experiment tested the influence of the vitamin E supplementation source (natural form in water v. the synthetic form in feed) and dose administered to piglets and/or sows on serum α-tocopherol concentration, α-tocopherol stereoisomer accumulation, antioxidant capacity and immune response of weaned piglets. A second experiment studied the effect of sow source and dose vitamin E supplementation on some of these parameters in piglets. Oral supplementation to sows with natural vitamin E as a micellized form (D-α-tocopherol) at the lowest dose produced a similar concentration of α-tocopherol in serum at days 2, 14 and 28 postpartum to those supplemented with threefold higher dose of the synthetic form in feed. At day 39 of age, neither piglet supplementation source nor dose significantly affected α-tocopherol accumulation in the serum, muscle, subcutaneous fat or liver. Those piglets from sows supplemented with the micellized alcohol form had higher RRR-α-tocopherol stereoisomers (P<0.001) and lower (P<0.001) RRS- RSS- and RSR-α-tocopherol, at day 39 of age than those from sows supplemented with the synthetic form. A predominant importance of sow over piglet vitamin E supplementation was observed on stereoisomer distribution in piglets. Low doses of oral natural vitamin E supplementation to sows or piglets did not increase the oxidative stress of piglets when compared with the use of the synthetic form in feed. Immunoglobulin levels in piglet serum at day 39 were not affected by natural vitamin E supplementation at low doses in drinking water of piglets or sows when compared with the synthetic form in feed. IgA tended to be higher (P=0.145) at day 39 in piglets supplemented with natural vitamin E when compared with those supplemented with the synthetic form. Low doses of oral micellized natural vitamin E supplementation to sows is an interesting feeding strategy, when compared with the use of high doses of the synthetic form in feed, because it results in similar α-tocopherol concentrations, allows a predominant -R stereoisomer distribution in piglets and also maintains their oxidative status in vivo.

Alpha-tocopherol stereoisomer analysis as discriminant method for distinguishing Iberian pig feed intake during the fattening phase.

The use of stereoisomers of α-tocopherol to correctly classify Iberian pig fat samples according to their feeding system was investigated. Samples were obtained over two different seasons in controlled farms from the four categories of pigs described in the Industry Quality Policy (FREE-RANGE: pigs fed exclusively under free-range conditions; FREE-FEED: pigs fed free-range and supplemented with feed; FEED-OUT: pigs fed outdoors with access to grass and a mixed diet; and FEED: pigs fed exclusively a mixed diet). A higher presence of RRR-stereoisomer indicated a greater consumption of the natural form of tocopherol provided by acorns or grass, whereas a higher proportion of S forms were related to a higher mixed diet intake. Validation results showed 90% success in fat sample classification. Analysis of the RRR-stereoisomer together with γ- and α-tocopherol determination can be considered as a potent tool for distinguishing fat from pigs fed under free-range conditions or exclusively with acorns and grass from those receiving a supplemented diet at any time of their fattening phase.

Short- and long-term effect of oral administration of micellized natural vitamin E (D-α-tocopherol) on oxidative status in race horses under intense training.

This study tested the effect of micellized vitamin E (D-α-tocopherol; 1,400 IU/d) administered 12 and 1 h orally before training for 1 d (ST-VitE) or 8 d (LT-VitE) compared with an unsupplemented control (CONTROL) on plasma α-tocopherol, thiobarbithuric acid-reactive substances (TBARS), total glutathione (GSHt), and trolox equivalent antioxidant capacity (TEAC) in 10 race horses. Different sampling times [immediately before training (BEF) and after intense training (END) or 8 h after recovery (+8h)] were investigated. Plasma α-tocopherol concentration was greater in the ST-VitE group than the CONTROL group at +8h (P < 0.05). Natural vitamin E supplementation increased plasma α-tocopherol (P < 0.001) in the LT-VitE group by approximately 1.6-fold at BEF, END, and +8h. In all groups, TBARS tended to be slightly greater (P = 0.087) immediately after training when compared with values BEF or +8h and the lowest TBARS values were observed at +8h in LT-VitE. Vitamin E supplementation did not affect the GSHt concentrations at BEF, END, or +8h. The TEAC values were modified by the vitamin E administration (P = 0.010). The greatest TEAC was found in the LT-VitE group at all sampling times and similar concentrations were reached in the ST-VitE group at +8h. The CONTROL group was not able to maintain TEAC after training (P < 0.001), indicating consumption of antioxidants (mainly vitamin E) and consequently oxidative stress because of the antioxidant system being overwhelmed by a reduced antioxidant supply. In conclusion, micellized natural vitamin E at 1,400 IU/d for 8 d efficiently increased plasma α-tocopherol concentration of race horses undergoing intense training conditions and maintained the general oxidative status.

Hyperthermic intra-peritoneal chemotherapy using oxaliplatin as consolidation therapy for advanced epithelial ovarian carcinoma. Results of a phase II prospective multicentre trial. CHIPOVAC study.

INTRODUCTION: The aim of the present study was to prospectively evaluate morbidity of intra-peritoneal hyperthermic chemotherapy (HIPEC) using Oxaliplatin as consolidation therapy for advanced epithelial ovarian carcinoma and, secondly, to study peritoneal recurrence. METHODS: Between 2004 and 2007, 31 patients from 18 to 65 years with FIGO stage IIIC epithelial ovarian carcinoma were treated by surgery and a total of 6 cycles of platinum based chemotherapy. Those patients were eligible for consolidation therapy. We performed a second look laparotomy operation with intra-peritoneal hyperthermic chemotherapy. We used Oxaliplatin 460 mg/m(2) with 2 l/m(2) of dextrose in an open medial laparotomy for a total of 30 min at a temperature of 42-44 degrees C. RESULTS: The grade 3 morbidity rate was 29% (95 CI: 14-45%). Nine patients experienced a total of 13 exploratory laparotomies for intra-abdominal bleeding after HIPEC. Two-year disease free and overall survival were 27% and 67% respectively. As a result of this high level of morbidity the trial was closed. CONCLUSION: Using intra-peritoneal Oxaliplatin associated with hyperthermia as consolidation therapy for advanced ovarian cancer results in a high risk of grade 3 morbidities with only a small benefit on survival.

Effect of diet saturation on growth performance, carcass characteristics and fat quality of heavy pigs.

Twenty-four castrated male (Duroc × Large Withe × Landrace) with an average weight of 69.4 kg were randomly distributed and located in individual cages and given the experimental diets. Diets were provided ad libitum and were formulated containing three levels of palm oil and hydropalm (hydrogenated palm stearine): 4% and 0% (low saturation), 2% and 2% (moderate saturation) and 0% and 4% (high saturation). Pigs were slaughtered at a local slaughterhouse with an average weight of 129.1 kg. The dietary treatment had no significant influence on growth performances and carcass characteristics. The diet saturation led to an increase of C18:0 and ΣSFA (saturated fatty acids) proportions and to a reduction of C18:1 n-9, C18:2 n-6 and ΣPUFA (polyunsaturated fatty acids) proportions and in subcutaneous backfat outer and inner layers. The dietary treatment affected significantly the melting point of subcutaneous backfat outer layer but had no significant influence on the melting point of the subcutaneous backfat inner layer. However, a linear effect of C18:0 proportion of subcutaneous backfat outer and inner layers on the melting point was observed. Dietary treatment had no significant effect on the main fatty acids pattern of intramuscular neutral and polar lipids from Longissimus dorsi muscle. In neutral lipids of liver a dietary influence (p < 0.05), but not a clear dose--response relationship, was observed for C16:0, C18:1 n-9, ΣSFA and ΣPUFA fatty acids, whereas in polar lipids the dietary treatment had no significant effect on the main fatty acids proportions. No effect of diet saturation was found on rheological properties of fat except for the hardness. The hardness was higher in the pigs that received the diet with 0% of palm oil and 4% hydropalm than in those given the diet with 4% of palm oil and 0% hydropalm.

Interactions between genotype, dietary fat saturation and vitamin A concentration on intramuscular fat content and fatty acid composition in pigs.

The effect of dietary fat saturation (dFat) and dietary vitamin A (dVitA) level (0 IU vs. 100,000 IU) on performance, carcass characteristics and fatty acid composition in the offspring of two terminal sires: Duroc (DU) and Landrace×Large White (LD×LW) was studied. In the inner backfat layer, the DU-sired pigs had higher C16:0 proportion (P<0.05) and tended (P<0.07) to have higher total saturated fatty acids (SFA) and lower C18:1 n-9 proportions than LD×LW-sired pigs. An interaction sire line×dVitA was observed for intramuscular fat (IMF) content (P<0.005). The effect of supplementation with the high dVitA level in DU-sired pigs was associated with a 20% increase in IMF while no effect was observed in LD×LW pigs. Fatty acid pattern was affected by dFat and sire line. In the inner backfat layer, LD×LW-sired pigs receiving the low dVitA level increased C18:0 proportions by 8% in comparison to animals receiving the high dVitA, whereas in DU-sired pigs the effect of vitamin A was opposite. It is concluded that the effect of dFat and dVitA concentration on IMF content and fatty acid profile of subcutaneous backfat and IMF is variable according to pig genotype.

Dietary vitamin A concentration alters fatty acid composition in pigs.

This experiment was conducted to study the effect of vitamin A concentration in the diet on fatty acid composition in pigs. One-hundred and twenty eight Duroc × (Large White × Landrace) castrated male pigs were used. Pigs were randomly distributed and located in cages of four pigs each to the following treatment: vitamin A-enriched diet (100,000IU/kg) (n=16) and control diet with a basal level (7500IU/kg) (n=16). The pigs were slaughtered at an average weight of 125.9kg. No effect of diet vitamin A level on performance, carcass traits and intramuscular fat percentage was observed. The retinol concentration in subcutaneous backfat and retinol and retinol palmitate contents in liver were higher in the pigs that were given the vitamin A enriched diet than in those receiving the control diet. However the vitamin A supplementation did not increase the retinol content in the muscle. Pigs receiving the vitamin A enriched diet showed a higher C16:0 and ∑SFA proportions in the outer layer and C18:0 and ∑SFA proportions in the inner layer. Moreover, the diet rich in vitamin A led to a reduction of C18:1 n-9 and ∑MUFA proportions in subcutaneous backfat inner layer. Dietary vitamin A concentration had not influence on main fatty acids composition of intramuscular lipids. Dietary vitamin A enrichment lead to a higher C16:0, ∑SFA concentration in liver lipids.

High dietary vitamin A interferes with tissue α-tocopherol concentrations in fattening pigs: a study that examines administration and withdrawal times.

This study aimed to assess the interaction between different dietary vitamin A (dVitA) levels and the same concentration of vitamin E (100 IU all-rac-α-tocopheryl acetate/kg feed) in growing-finishing pigs. In the first experiment, two fat sources × two dVitA levels (0 v. 100 000 IU) were used. The supplementation of 100 000 IU dVitA induced a range of 5.13 to 30.03 µg retinol/g liver, 62.78 to 426.88 µg retinol palmitate/g liver, and 0.60 to 1.96 µg retinol/g fat. Dietary fat did not affect retinol or retinyl palmitate deposition in pigs. The high concentration of dVitA produced lower fat and liver α-tocopherol concentrations, and increased susceptibility of muscle tissue to oxidation. A second experiment was carried out to study the retinol and α-tocopherol retention at different withdrawal times prior to slaughter (two dVitA levels; 0 v. 100 000 IU). A high dose of 100 000 IU vitamin A during a short 2-week period was enough to induce α-tocopherol depletion in liver and fat to a similar extent as when 100 000 IU were administered during the whole fattening. Muscle, fat and liver α-tocopherol concentrations were not affected by dVitA in the 1300-13 000 IU/kg range, but liver α-tocopherol concentration was higher when vitamin A was removed from the vitamin mix 5 weeks prior to slaughter (experiment 3).

Effects of feeding in free-range conditions or in confinement with different dietary MUFA/PUFA ratios and α-tocopheryl acetate, on antioxidants accumulation and oxidative stability in Iberian pigs.

The experiment was undertaken to provide information of the influence of feeding either free-range or in confinement with different dietary MUFA/PUFA ratios and α-tocopheryl acetate supplementation (40 vs. 200 mg/kg) on tocopherol content and susceptibility to lipid oxidation of muscle and microsomes in Iberian pigs. The grass provided to the pigs had a similar α-tocopherol concentration to that observed for diets supplemented with 200 mg/kg α-tocopheryl acetate, and acorns supplied fourfold higher content of γ-tocopherol than the experimental diets. The α- and γ-tocopherol contents of muscle reflected the tocopherol concentration of the diets. Mono and Medium diets produced a similar MUFA/PUFA ratio in neutral and polar lipids of pig muscle to those fed outdoors. The lowest TBARS numbers were found in muscle samples from pigs fed a MUFA-enriched diet in confinement. No significant influence of free-range feeding or dietary fat on drip loss was found. However, α-tocopheryl acetate supplementation reduced (P<0.05) drip loss. Dietary vitamin E supplementation decreased the membrane lipid oxidation by 18% after 120 min. However, free-range feeding decreased the extent of microsome oxidation by 20%, 56% and 82% after 120 min when compared with those groups fed in confinement with high, medium and low MUFA/PUFA ratios, respectively. The hexanal concentration of muscle showed a similar trend to that observed for microsome induced-oxidation, suggesting, that hexanal determination is a more accurate method to measure lipid oxidation in iberian pig muscle than the thiobarbituric acid test.

Effect of dietary vitamin E and partial replacement of poly- with monounsaturated fat on fatty acid patterns of backfat and intramuscular fat in heavy pigs (Iberian x Duroc).

The effects of partial replacement of dietary polyunsaturated fatty acid (PUFA) with monounsaturated fatty acid (MUFA) on fatty acid profiles of subcutaneous and intramuscular fat and rheological properties of fat were studied in heavy pigs. No effect of dietary fat was observed on total saturated fatty acids proportion in outer and inner backfat layers or intramuscular neutral and polar lipids. The partial substitution of dietary PUFA by MUFA produced a rise in MUFA of intramuscular polar lipids (p < 0.01) but neutral lipids were not affected. Moreover, it also decreased (p < 0.01) the n-6 proportion of outer and inner backfat layers and intramuscular polar lipids, but no effect was observed for the n-6 in the intramuscular neutral lipids. No significant effect of dietary fat treatment was observed on n-3 fatty acids in outer and inner backfat layers, but the partial substitution of PUFA by MUFA increased (p < 0.01) the n-3 proportion of intramuscular lipid fractions and the consequent decreased in the n-6/n-3 ratio in all lipid location. Significant effects of dietary vitamin E were observed on springiness, cohesiveness and adhesiveness of backfat inner layer. However, consistency was not affected by dietary fat. Further research is needed to establish the effects of different ranges of dietary oil combination in the feeding of heavy pigs.

Cortisol and dehydroepiandrosterone affect the response of peripheral blood mononuclear cells to mycobacterial antigens during tuberculosis.

The effect of cortisol and/or dehydroepiandrosterone (DHEA) on the immune response to antigens obtained from Mycobacterium tuberculosis was studied in vitro by using peripheral blood mononuclear cells obtained from patients at various stages of lung tuberculosis (TB) and from healthy control people (HCo). The results obtained show for the first time that addition of cortisol within concentrations of physiological range can inhibit the mycobacterial antigen-driven proliferation of cells from HCo and TB patients and the production of interferon-gamma (IFN-gamma), indicating that endogenous levels of cortisol may contribute to the decreased lymphoid cell response to mycobacterium antigens observed in TB patients. DHEA did not affect lymphoid cell proliferation, IFN-gamma production and the cortisol-mediated inhibitory effects. Interestingly, we found that DHEA, but not cortisol, suppressed the in vitro transforming growth factor-beta production by lymphoid cells from TB patients with an advanced disease, which is indicative of a selective direct effect of this hormone.

Effect of dietary copper and vitamin E supplementation, and extensive feeding with acorn and grass on longissimus muscle composition and susceptibility to oxidation in Iberian pigs.

The objective of this study was to assess the effect of dietary copper and/or vitamin E supplementation on composition and oxidation of M. longissimus in Iberian pigs and to compare it with meat samples from pigs produced extensively and fed with acorn and grass. Grass had the highest alpha-tocopherol content (> 150 mg/kg DM), while acorns had the highest copper concentration (78.1 mg/kg DM). Dietary treatment did not affect copper composition in muscle and no interactions were detected between copper and alpha-tocopherol. The alpha-tocopherol content in muscle from pigs fed diets supplemented with alpha-tocopheryl acetate (100 mg/kg feed) was 1.5 times greater (p < 0.0001) than those from pigs receiving a basel diet. M. longisssimus dorsi from pigs fed extensively had a higher concentration of alpha-tocopherol than those fed in confinement with the basel level of alpha-tocopheryl acetate, but lower values than pigs fed supplemented levels. Total n-3 fatty acids (p < 0.02) and hematin (p < 0.0001) concentrations were significantly higher in muscle from pigs fed extensively than when fed in confinement. Muscle homogenates from Iberian pigs fed in extensive conditions showed significantly (p < 0.02) higher susceptibility to oxidation than those from pigs fed mixed diets. Dietary alpha-tocopheryl acetate supplementation (100 mg/kg feed) significantly (p < 0.05) reduced lipid oxidation of muscle, while dietary copper concentration did not modify susceptibility to lipid oxidation.