A. Olivares

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.

Fatty Acids Profile of the Subcutaneous Backfat Layers from Iberian Pigs Raised Under Free-range Conditions

The aim of this study was to investigate the fatty acid composition of the outer, inner and subinner subcutaneous backfat layers from Iberian pigs raised under free-range conditions. The pigs were fattened on acorns and grass under free-range conditions from 101 to 155 kg of live weight. Proportions of C16:0, C18:0 and C20:0 were lower in the outer than in the inner layer, while the C12:0, C16:0 and C18:0 contents were higher in the subinner layer than in the inner layer. The outer layer had higher C15:1, C16:1 n-7, C17:1, C18:1 n-7 and similar C16:1 n-9, C18:1 n-9 and C20:1 n-9 proportions than the inner layer, while the subinner layer had lower C17:1, C18:1 n-9, C20:1, similar C15:1, C16:1 n-7, C18:1 n-7 and higher C16:1 n-9 proportions than the inner layer. Only the concentrations of C18:3 n-3, C18:4 n-3 and C20:3 n-3 were lower in subinner than in inner layer. The content of all polyunsaturated fatty acids (PUFA) was higher in the outer than in the inner layer except for the C20:4 n-6 fatty acid. A tendency (P < 0.1) to a higher Σ n-6/Σ n-3 fatty acids ratio was found for the inner and subinner layers than for the outer layer. Significant correlation coefficients were observed between the proportions of C14:0, C16:0, C18:1 n-9, C18:2 n-6, C18:3 n-3 and C20:3 n-9 of the inner layer and subinner layer. The outer layer melting point (MP) was lower than those of the inner and subinner layers, although no difference for MP between inner and subinner layers was observed.

Physical activity-induced alterations on tissue lipid composition and lipid metabolism in fattening pigs.

In a first experiment one group of pigs was maintained in free-range conditions according to the traditional way in a Mediterranean forest (exercised-1) and another group was housed individually and received acorns (sedentary-1). In a second experiment two groups of pigs were fed a mixed diet for the whole experimental period. One of these groups was housed individually in 8m(2) pens (sedentary-2). The other group was housed in a corridor and forced to walk daily (exercised-2). The subcutaneous fat and neutral lipids of muscle from the exercised pigs fed acorns had higher C18:1n-9, MUFA, C18:1/C18:0, MUFA/SAT and lower C16:0 and SAT when compared with the fat from the pigs fed acorns in confinement. Those exercised animals fed the mixed diet had also lower C16:0 and SAT in subcutaneous fat and lower SAT and higher C18:2, C18:3, PUFA and MUFA/SAT in neutral lipids when compared with the sedentary pigs, which may indicate that delta-9-desaturase activity was higher in exercised than in sedentary pigs. Exercised pigs had higher acid and neutral esterases and lower neutral lipase activity than sedentary pigs. No differences in the α-tocopherol concentration and TBARS values of meat samples among the pigs that received a mixed diet either exercised or sedentary were observed. The moderate exercise reduced the postprandrial concentrations of triglycerides in plasma, but did not reduce other plasma levels.

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.

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).

Fluoxetine combined with clorazepate dipotassium and behaviour modification for treatment of anxiety-related disorders in dogs.

The effectiveness of clorazepate dipotassium combined with fluoxetine and a behaviour modification programme for the treatment of anxiety disorders in dogs was investigated. Forty dogs with anxiety disorders were initially enrolled and 36 dogs completed the trial. Dogs were classified into two behavioural categories (anxious dogs with aggression and anxious dogs without aggression) according to their presenting complaints, and were also subdivided into males, females, juveniles and adults. The dog owners were provided with a behaviour modification plan for their dogs to be commenced in the first week of therapy. Clorazepate dipotassium was administered PO at 1.0 mg/kg every 24 h for 4 weeks, and fluoxetine was administered PO at 1.0 mg/kg every 24 h for 10 weeks. Therapy with both drugs was initiated simultaneously. Improvement was reported in 25/36 dogs. Significant differences in treatment effects were observed between anxious dogs with aggression and anxious dogs without aggression (P<0.05). Positive correlations between owner compliance with the treatment plan and reported improvement achieved during three periods of study were also noted.

Effect of mediterranean forest parasite with Curculio sp. on nutritional value of acorn for Iberian pig feeding and fat characteristics

Sixteen Iberian barrows of the same age with an average initial live weight of 100.1kg were randomly distributed in two groups of eight pigs each. One group was fed healthy acorns and the other group received acorns infested of Curculio sp. The subcutaneous backfat from pigs fed healthy acorns had higher C18:1n-9, MUFA and C20:5n-3 and lower C18:0 and SFA proportions than that from the pigs fed acorns infested with Curculio. The consumption of acorns infested with Curculio sp. led to a reduction of C18:1n-9, MUFA, C18:2n-6, C18:3n-3, C22:5n-3 and PUFA proportions in neutral lipids from Longissimus dorsi muscle with respect to consumption of healthy acorns, whereas in polar lipids it produced a reduction in C18:1n-9, MUFA and C18:4n-3 proportions and an increase in C18:2n-6, C20:4n-6, n-6 and C20:5n-3 proportions and of n-6/n-3 ratio with respect to the healthy acorns consumption. The pigs fed healthy acorns had higher intramuscular fat percentage in Longissimus dorsi than pigs fed with acorns infested with Curculio (9.95 vs 7.09% SEM=0.60).

Effect of age at the beginning of the free-range fattening period on growth and carcass and fat quality in Iberian pigs

Abstract This experiment was carried out to study the influence of age at the beginning of the free-range fattening period (traditional pigs, TP, age 12 months vs. young pigs, YP, age 8 months) on the performance of Iberian pigs. During 152 days prior to the fattening period, TP and YP pigs received 1.7 and 2.6 kg feed per day, respectively. During fattening, TP pigs had a higher average daily gain (p < 0.05) than YP pigs. The proportions of PUFA and n-3 fatty acids of the outer and inner layers of subcutaneous backfat were higher in TP than in YP pigs (p < 0.05), while the proportions of C16:0 and SFA in the inner layer of subcutaneous backfat were greater in YP than in TP pigs (p < 0.05). The ratio of n-6/n-3 in subcutaneous backfat was lower in TP than in YP pigs (p < 0.05). The percentage of intramuscular fat in longissimus dorsi muscle was higher in TP than in YP pigs (p < 0.05). The relationship between the percentage of intramuscular fat in longissimus dorsi muscle and average daily gain during the free-range fattening period adjusted to a quadratic function (p < 0.05). The concentration of α- and γ-tocopherol in subcutaneous backfat at slaughter was significantly higher in TP than in YP pigs (p < 0.05). It is concluded that Iberian pigs that have 8 months of age at the beginning of free-range feeding have adequate commercial quality.

The effect of immunocastration and a diet based on granulated barley on growth performance and carcass, meat and fat quality in heavy gilts.

A total of 48 Duroc × (Landrace × Large White) gilts of 33.2 kg BW were used to investigate the influence of immunocastration and diet on growth performance and carcass, meat and fat quality. Four treatments were arranged factorially (2 × 2) with two sexes (immunocastrated gilts: IG v. entire gilts: EG) and two dietary treatments (a commercial feedstuff as control v. granulated barley as a single major ingredient) provided during the finishing period (from 103 to 126 kg BW). There were four replicates of three pigs per treatment. At the end of the trial, the IGs grew faster (P<0.05) and ate more feed (P<0.05) than the EGs. Carcasses from the IGs had thicker backfat depth than those from the EGs (P<0.01) and carried out a lower percentage of rejected carcasses (P<0.05) at slaughterhouse owing to lack of fat. Meat from the IGs tended to have higher intramuscular fat (IMF) content in the Longissimus thoracis (LT) muscle than that from the EGs (P=0.09). In addition, immunocastration increased the total saturated fatty-acid proportion in subcutaneous fat and IMF (P<0.001) and decreased the total monounsaturated fatty acid (MUFA) and total polyunsaturated fatty acid (PUFA) percentages in subcutaneous backfat (P<0.05 and P<0.001, respectively) and in IMF (P<0.01 and P=0.06, respectively). The use of a diet based on granulated barley during the finishing period had no effect on growth performance but tended to increase IMF content in the LT muscle (P<0.06), and increased MUFA (P<0.05) and decreased PUFA (P<0.01) proportions in omental fat. It is concluded that immunocastration of gilts intended for dry-cured ham industry improved some aspects of growth performance and carcass and meat quality, whereas granulated barley had scarce effect on productive traits and fatty-acid profile but tended to improve IMF content.