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.

Adipose tissue transcriptional response of lipid metabolism genes in growing Iberian pigs fed oleic acid v. carbohydrate enriched diets.

Diet influences animal body and tissue composition due to direct deposition and to the nutrients effects on metabolism. The influence of specific nutrients on the molecular regulation of lipogenesis is not well characterized and is known to be influenced by many factors including timing and physiological status. A trial was performed to study the effects of different dietary energy sources on lipogenic genes transcription in ham adipose tissue of Iberian pigs, at different growth periods and on feeding/fasting situations. A total of 27 Iberian male pigs of 28 kg BW were allocated to two separate groups and fed with different isocaloric feeding regimens: standard diet with carbohydrates as energy source (CH) or diet enriched with high oleic sunflower oil (HO). Ham subcutaneous adipose tissue was sampled by biopsy at growing (44 kg mean BW) and finishing (100 kg mean BW) periods. The first sampling was performed on fasted animals, while the last sampling was performed twice, with animals fasted overnight and 3 h after refeeding. Effects of diet, growth period and feeding/fasting status on gene expression were explored quantifying the expression of a panel of key genes implicated in lipogenesis and lipid metabolism processes. Quantitative PCR revealed several differentially expressed genes according to diet, with similar results at both timings: RXRG, LEP and FABP5 genes were upregulated in HO group while ME1, FASN, ACACA and ELOVL6 were upregulated in CH. The diet effect on ME1 gene expression was conditional on feeding/fasting status, with the higher ME1 gene expression in CH than HO groups, observed only in fasting samples. Results are compatible with a higher de novo endogenous synthesis of fatty acids (FA) in the carbohydrate-supplemented group and a higher FA transport in the oleic acid-supplemented group. Growth period significantly affected the expression of most of the studied genes, with all but PPARG showing higher expression in finishing pigs according to a pattern dissimilar from the usual in cosmopolitan pig breeds. Feeding/fasting status only influenced PPARG gene transcription. The lack of effects of feeding/fasting status on lipogenic gene expression and the higher ME1 response to diet in fasting samples than in postprandial sampling, suggest the persistence of de novo lipogenesis during fasting. Overall results improve the understanding of the influence of different factors on lipid metabolism regulation in Iberian pigs.

Effect of management (organic vs conventional) on volatile profiles of six plum cultivars (Prunus salicina Lindl.). A chemometric approach for varietal classification and determination of potential markers.

The volatile profiles of six plum cultivars ('Laetitia', 'Primetime', 'Sapphire', 'Showtime', 'Songold' and 'Souvenir') produced under two management systems (conventional and organic) and harvested in two consecutive years were obtained by HS-SPME-GC-MS. Twenty-five metabolites were determined, five of which (pentanal, (E)-2-heptenal, 1-octanol, eucalyptol and 2-pentylfuran) are reported for the first time in Prunus salicina Lindl. Hexanal stood out as a major volatile compound affected by the management system. In addition, partial least square discriminant analysis (PLS-DA) achieved an effective classification of genotypes based on their volatile profiles. A high classification accuracy model was obtained with a sensitivity of 97.9% and a specificity of 99.6%. Furthermore, the application of a dual criterion, based on a method of variable selection, VIP (variable importance in projection) and the results of a univariate analysis (ANOVA), allowed the identification of potential volatile markers in 'Primetime', 'Showtime' and 'Souvenir' genotypes (cultivars not characterised to date).

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.

Dietary CLA alters intramuscular fat and fatty acid composition of pig skeletal muscle and subcutaneous adipose tissue.

The present study was conducted to determinate the responsiveness of different levels of dietary conjugated linoleic acid (CLA) on intramuscular fat (IMF) and fatty acid composition of skeletal muscle and fat in pigs fed from 59.5 to 133.5kg. Forty female Large Whitex(Large WhitexLandrace) pigs were used. Four levels (0%, 0.5%, 1% and 2%) of a commercial enriched CLA oil supplementation (60% of CLA isomers, 30% cis-9, trans-11 and 30% trans-10, cis-12) were fed to pigs. Carcass, ham, foreleg and loin weights were recorded. Dietary CLA enrichment increased the loin weight (P<0.01) and the combined weights of hams+forelegs+loins (P<0.02). IMF content in Longissimus dorsi was also increased by dietary CLA treatment (P<0.001) and a linear response was observed. Dietary CLA increased saturated fatty acids (SFA) and decreased monounsaturated fatty acids (MUFA) in muscle and adipose tissue (P<0.001). Feeding 1% CLA to finishing swine increases IMF in heavy pigs slaughtered at an average weight of 133.5kg.

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.

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).

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.

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.

Effect of vitamin E supplementation and partial substitution of poly- with mono-unsaturated fatty acids in pig diets on muscle, and microsome extract alpha-tocopherol concentration and lipid oxidation.

The experiment was organized in a 3 x 2 factorial arrangement with three dietary fat blends and a basal (20 mg kg(-1) diet) or supplemented (220 mg kg(-1)) level of alpha-tocopheryl acetate. Dietary vitamin E and monounsaturated to polyunsaturated fatty acid ratio (dietary MUFA/PUFA) affected muscle alpha-tocopherol concentration (alpha-tocopherol [log microg g(-1)] = 0.18 (+/- 0.105) + 0.0034 (+/- 0.0003) x dietary alpha-tocopherol [mg kg(-1) diet] (P < 0.0001) + 0.39 (+/- 0.122) x dietary MUFA/PUFA (P < 0.0036)). An interaction between dietary alpha-tocopherol and dietary MUFA/PUFA exists for microsome alpha-tocopherol concentration (alpha-tocopherol [log microg g(-1)] = 1.14 ( +/- 0.169) (P < 0.0001) + 0.0056 ( +/- 0.00099) x dietary alpha-tocopherol [mg kg(-1) diet] (P <0.0001) + 0.54 (+/- 0.206) x dietary MUFA/PUFA (P < 0.0131) - 0.0033 (+/- 0.0011) x dietary alpha-tocopherol [mg kg(-1))] x dietary MUFA/PUFA (P < 0.0067)), and hexanal concentration in meat (hexanal [ng x g(-1)] = 14807.9 (+/- 1489.8)- 28.8 (+/- 10.6) dietary alpha-tocopherol [mg x kg(-1)] (P < 0.01) - 8436.6 (+/- 1701.6) x dietary MUFA/PUFA (P < 0.001) + 24.0 (+/- 11.22) x dietary alpha-tocopherol-dietary MUFA/ PUFA (P < 0.0416)). It is concluded that partial substitution of dietary PUFA with MUFA lead to an increase in the concentration of alpha-tocopherol in muscle and microsome extracts. An interaction between dietary alpha-tocopherol and fatty acids exists, in which at low level of dietary vitamin E inclusion, a low MUFA/ PUFA ratio leads to a reduction in the concentration of alpha-tocopherol in microsome extracts and a concentration of hexanal in meat above the expected values.

Bronchial, alveolar, and vascular-induced anaphylaxis and irritant-induced cardiovascular and pulmonary responses.

We examine the respiratory, bronchomotor, cardiac, and vascular responses to histamine and ragweed allergen delivered to the bronchi or alveoli compartments and the potential role of sensory nerves and reflexes mediating the histamine-induced responses. The masses of aerosols deposited in the bronchi and alveoli were quantitated using radioaerosol techniques. Activation of sensory nerves and/or histamine-induced mediator release were characterized by depositing nedocromil sodium aerosol prior to histamine challenge. The histamine-induced responses due to vagosympathetic transmission were determined by performing bilateral vagotomy. Both histamine and ragweed increased respiratory rate, ventilation, and bronchomotor tone whether deposited in the bronchial or alveolar regions. However, these responses were not elicited when histamine was administered intravenously. Precipitous allergen-induced decreases in heart rate and systolic and diastolic pressure were maximal 72 sec following ragweed deposition in alveolar regions of the lungs. Increases in respiratory rate were mediated via the vagus whether delivered to the bronchi, alveoli, or vasculature. Histamine-induced increases in respiratory rate and bronchomotor tone were attenuated by nedocromil. When histamine was delivered to the alveolar regions, increases in lung resistance appeared to be mediated primarily via the vagus and when delivered to the bronchial airways primarily by its action on smooth muscle or local reflexes. Histamine-induced hypotension and bradycardia appear to be mediated by the direct action of histamine on the cardiovascular system rather than through a vagally mediated reflex.

Characterization of rhizobial isolates of Phaseolus vulgaris by staircase electrophoresis of low-molecular-weight RNA.

Low-molecular-weight (LMW) RNA molecules were analyzed to characterize rhizobial isolates that nodulate the common bean growing in Spain. Since LMW RNA profiles, determined by staircase electrophoresis, varied across the rhizobial species nodulating beans, we demonstrated that bean isolates recovered from Spanish soils presumptively could be characterized as Rhizobium etli, Rhizobium gallicum, Rhizobium giardinii, Rhizobium leguminosarum bv. viciae and bv. trifolii, and Sinorhizobium fredii.

Bronchial and alveolar allergen-induced anaphylaxis and the stimulation of bronchial mucociliary clearance in ragweed-sensitized dogs.

In allergic airways disease, we hypothesized that an acute allergen inhalation activates cells in the bronchial and alveolar regions of the lungs to initiate cardiopulmonary anaphylactic responses that include the stimulation of bronchial mucociliary clearance. Seven beagles were neonatally sensitized to ragweed allergen, and four were sham-sensitized. Adult dogs were anesthetized with propofol and etomidate. Bronchial retention of radiotagged particles deposited in the lungs was monitored with a gamma camera. Then 0.4-1.8 micrograms of ragweed allergen was deposited either proximally or peripherally in the lungs while achieving a similar total mass deposited. Both proximal and peripheral allergen deposition elicited cardiopulmonary responses characteristic of anaphylaxis. Following proximal allergen deposition, the mean bronchial mucuciliary clearance at 60 min increased from 27.5% +/- 4.9% to 59.9% +/- 3.3% (p < .01), and following peripheral deposition it increased from 5.9% +/- 3.1% to 52.9% +/- 7.2% (p < .01). No allergen-induced suppression of bronchial mucociliary clearance was detected within the 140-min postexposure period. No changes in cardiopulmonary responses or bronchial mucociliary clearance in the unsensitized dogs could be ascribed to the inhalation of allergen. Both the bronchi and alveoli are target sites for the initiation of allergen-induced respiratory and cardiovascular anaphylactic responses and the stimulation of bronchial mucociliary clearance.

Sporulation of several species of Streptomyces in submerged cultures after nutritional downshift.

Streptomyces griseus ATCC 10137, S. griseus IMRU 3570, S. griseus JI 2212, S. acrimycini JI 2236 and S. albus G sporulated abundantly in several liquid media after nutritional downshift. Spores formed in submerged cultures were viable and as thermoresistant as aerial spores. Scanning electron microscopy showed that submerged spores are morphologically similar to aerial spores. The sporulation of the Streptomyces strains tested in complex medium appeared to be triggered by phosphate nutritional downshift, induced by addition of Ca2+ to the medium. Spore-shaped bodies were formed by S. lividans JI 1326 and S. coelicolor JI 2280 when grown in complex medium supplemented with Ca2+ and proline. The thermoresistance of these spore-shaped bodies differed from that of aerial spores.