Effect of sex,dietary glycerol or dietary fat during late fattening,on fatty acid composition and positional distribution of fatty acids within the triglyceride in pigs

The effect of sex, source of saturated fat (lard v. palm oil) and glycerol inclusion in the fattening diet on composition and fatty acid positional distribution in the triglyceride molecule was studied in pigs from 78 to 110 kg BW. Average daily gain and carcass characteristics, including ham and loin weight, were not affected by dietary treatment but sex affected backfat depth (P<0.01). A significant interaction between sex and glycerol inclusion was observed; dietary glycerol increased lean content in gilts but not in barrows (P<0.05 for the interaction). Individual and total saturated fatty acid (SFA) concentrations were greater in barrows than in gilts. In contrast, the concentration of total polyunsaturated fatty acids (PUFA) and of C18:2n-6, C18:3n-3, C20:3n-9 and C20:4n-6 in the intramuscular fat (IMF) was higher (P<0.05) in gilts than in barrows. Sex did not affect total monounsaturated fatty acids (MUFA) concentration in the IMF. The proportion of SFA in the subcutaneous fat (SF) was higher in barrows than in gilts (P<0.001). Within the individual SFA, sex affected only the concentrations of C14:0 and C16:0 (P<0.001). Dietary fat did not affect total SFA or PUFA concentrations of the IMF but the subcutaneous total MUFA concentration tended to be higher (P=0.079) in pigs fed lard than in pigs fed palm oil. Dietary glycerol increased total MUFA and C18:1n-9 concentration in the IMF and increased total MUFA and decreased C18:2n-6, C18:3n-3 and total PUFA concentrations in the SF. The data indicate that altering the fatty acid composition of the triglyceride molecule at the 2-position, by dietary intervention during the fattening phase, is very limited.     

Evaluation of energy systems in determining the energy cost of gain of growing-finishing pigs fed diets containing different levels of dietary fat

Two experiments were conducted to evaluate the impact of different energy systems in predicting the energy cost of gain of growing-finishing pigs fed diets containing different levels of dietary fat. The diets in both experiments were based on wheat, corn and soybean meal and supplemented with 0, 1.75, 3.50 and 5.25% tallow. In Experiment 1, 24 crossbred barrows (Duroc x Landrace x Yorkshire) were randomly allocated to one of the four dietary treatments to determine the digestible (DE) and metabolizable (ME) energy content of the diets and net energy (NE) was calculated from DE and ME values. In Experiment 2, 96 crossbred barrows (Duroc x Landrace x Yorkshire) were used to evaluate the effectiveness of the energy systems in predicting the energy cost of gain for growing-finishing pigs fed ad libitum. There were six pens per treatment and four pigs per pen. The results obtained in trial 1 were used for calculating the energy cost of gain in trial 2. During the growing period, there was a linear decrease (p < 0.05) in the DE and ME cost of gain, while the NE cost of gain was not influenced by level of fat. During the finishing period, neither DE, ME or NE cost of gain were influenced by the dietary fat level. For the total experiment, the DE and ME cost of gain decreased (linear effect; p = 0.001), but there was no significant decrease in the NE cost of gain. It is concluded that the NE system can predict the performance of growing-finishing pigs more precisely for diets differing in fat content than can the DE and ME systems.     

Productive performance, carcass and meat quality of intact and castrated gilts slaughtered at 106 or 122 kg BW

A total of 200 (Landrace × Large White dam × Pietrain × Large White sire) gilts of 50 ± 3 days of age (23.3 ± 1.47 kg BW) were used to investigate the effects of castration (intact gilt, IG v. castrated gilt, CG) and slaughter weight (SW; 106 v. 122 kg BW) on productive performance, carcass and meat quality. Four treatments were arranged factorially and five replicates of 10 pigs each per treatment. Half of the gilts were ovariectomized at 58 days of age (8 days after the beginning of the trial at 29.8 ± 1.64 kg BW), whereas the other half remained intact. The pigs were slaughtered at 106 or 122 kg BW. Meat samples were taken at Musculus longissimus thoracis at the level of the last rib and subcutaneous fat samples were taken at the tail insertion. For the entire experimental period, CG had higher (P < 0.05) BW gain and higher (P < 0.001) backfat and Musculus gluteus medius fat thickness than IG. However, IG had higher (P < 0.05) loin and trimmed primal cut yields than CG. Meat quality was similar for IG and CG but the proportion of linoleic acid in subcutaneous fat was higher (P < 0.001) for IG. Pigs slaughtered at 122 kg BW had higher (P < 0.001) feed intake and poorer feed efficiency than pigs slaughtered at 106 kg BW. An increase in SW improved (P < 0.001) carcass yield but decreased (P < 0.05) trimmed primal cut yield. Meat from pigs slaughtered at the heavier BW was redder (a*; P < 0.001) and had more (P < 0.01) intramuscular fat and less thawing (P < 0.05) and cooking (P < 0.10) loss than meat from pigs slaughtered at the lighter BW. In addition, pigs slaughtered at 122 kg BW had less (P < 0.01) linoleic acid content in subcutaneous fat than pigs slaughtered at 106 kg BW. Castration of gilts and slaughtering at heavier BW are useful practices for the production of heavy pigs destined to the dry-cured industry in which a certain amount of fat in the carcass is required. In contrast, when the carcasses are destined to fresh meat production, IG slaughtered at 106 kg BW is a more efficient alternative.     

Effects of conjugated linoleic acid levels and feeding intervals on performance, carcass traits and fatty acid composition of finishing barrows

Two experiments were conducted to investigate the effects of dietary conjugated linoleic acid (CLA) on performance, carcass traits, fatty acid composition and subcutaneous adipose tissue cellularity in finishing barrows. In Experiment 1, 54 crossbred barrows were allotted to one of three treatments, with six pens per treatment and three barrows in each pen. The pigs were fed a diet containing 0, 2, or 4% CLA oil for 6 weeks. Daily gain (P < 0.01) and feed efficiency (P < 0.01) improved with dietary CLA. Loin muscle area (P = 0.01) and intramuscular fat (P = 0.01) increased while 10th rib fat (P = 0.03) and last rib fat (P = 0.02) thickness decreased with increasing dietary CLA. Total CLA isomers increased (P < 0.01) with increasing dietary CLA. Myristic, palmitic and stearic acid levels were increased while oleic, linoleic, linolenic and arachidonic acid decreased in loin muscle and subcutaneous adipose tissue. In Experiment 2, barrows (n = 54) were allotted to one of two treatments with nine pens per treatment and three pigs in each pen. Pigs were fed a diet supplemented with 4% CLA for 3 or 6 weeks before slaughter. Over the entire experimental period, daily gain and feed efficiency were higher (P < 0.01) when CLA was fed for a longer period. Loin muscle area (P < 0.01) and intramuscular fat (P < 0.01) increased while backfat thickness at the 10th (P = 0.03) and last rib (P = 0.04) decreased when CLA was fed for 6 vs. 3 weeks. The number of cells in subcutaneous adipose tissue was not affected while adipocyte volume decreased (P = 0.01) with longer feeding time on dietary CLA. The increased CLA content of pork from CLA fed pigs provides the pork industry with an opportunity to provide value-added, healthful meat products for human consumption with respect to CLA intake and potential improvements in human health.     

Involvement of Zn Depletion in Cd-Induced Toxicity on Prenatal Bone Formation in Rat

This experiment was conducted to evaluate the effects of chromium methionine with/without zinc sulfate or zinc amino acid complex on the growth performance, carcass traits, meat quality, serum parameters, endocrine parameters, and antioxidant status of growing-finishing pigs. A total of 180 (32.0 ± 1.7 kg body weight, BW) crossbred pigs (Duroc × Landrace × Yorkshire) were used in a completely randomized design with three dietary treatments and 10 replicates per treatment (five pens of barrows and five pens of gilts with six pigs per replicate). Three treatments were corn-soybean meal-based diets supplemented with 100 mg Zn/kg from zinc sulfate (ZnSO₄), 100 mg Zn/kg from ZnSO₄ + 0.2 mg Cr/kg from chromium methionine complex (CrMet), or 50 mg Zn/kg from ZnSO₄ + 50 mg Zn/kg from zinc amino acid complex (ZnAA) + 0.2 mg Cr/kg from CrMet, respectively. The experiment lasted 105 days, of which was divided into three stages including phase 1 (30 to 50 kg BW), phase 2 (50 to 80 kg BW), and phase 3 (80 to 110 kg BW). Results showed that supplementation with CrMet and ZnAA improved (P < 0.05) the feed conversion of the pigs in phase 2, phase 3, and the overall experiment. Hot carcass weight, dressing percentage, and a longissimus dorsi muscle area were increased (P < 0.05) in pigs fed with diets supplemented with both CrMet and ZnAA compared with pigs fed with diets containing only ZnSO₄ (P < 0.05). There was also an increase (P < 0.01) pH_24 h in the longissimus dorsi muscle in pigs fed with diets supplemented with CrMet and ZnAA. The concentration of serum glucose in pigs fed with diets containing CrMet and ZnAA was decreased (P < 0.05) compared with that in pigs fed with the diet containing ZnSO₄. Supplementation with CrMet and ZnAA increased (P < 0.05) the circulating levels of insulin and decreased (P < 0.05) cortisol. There was an increase (P < 0.05) in total serum antioxidant capacity and Cu/Zn superoxide dismutase activity as well as a decrease (P < 0.05) in serum malondialdehyde concentrations in pigs fed with diets supplemented with CrMet and ZnAA compared with pigs fed with the diet supplemented only with ZnSO₄. In conclusion, supplementation of CrMet only or CrMet together with ZnAA improved feed conversion, carcass traits, and meat quality in the growing-finishing pigs.     

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

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 alpha- and gamma-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.     

Digestibility of phosphorous in cereals and co-products for animal feed

Feed ingredients used in swine diets contain various levels and availabilities of nutrients. Nutritional precision evaluation of each ingredient is necessary for formulating diets of pigs. Especially, phosphorous (P) is one of important nutrients for metabolism. However, current data of P digestibility were most apparent digestibility. Therefore, this study was aimed to estimate the coefficient of total tract standardized digestibility (CTTSD) of P in cereals and various co-products used in pig diet. Twelve barrows (initial BW?±?SD, 46.70?±?3.21?kg) were used in this experiment. The experimental design was a 12?×?8 incomplete Latin square with 12 diets and 8 periods. Experimental diets were consisted of barley, wheat, lupine kernel (LK), soybean meal (SBM), almond meal (AM), corn gluten meal (CGM), corn gluten feed from China (CGF-C), corn gluten feed from Korea (CGF-C), wheat bran (WB), rice bran (RB), lupine hull (LH) and P-free diet. The CTTAD of Ca was higher in AM than RB and CGF-K. The LK and CGM showed greater CTTSD of P than RB and LH. In conclusion, our results indicated that the cereals and co-products as P sources were the ideally used as an ingredient in mixed diets of the growing-finishing pigs.     

Influence of rearing system,diet and gender on performance,carcass traits and meat quality of Polish Landrace pigs

Forty-eight Polish Landrace pigs (initially 32.43 ± 0.70 kg live weight) were assigned to a 2 × 2 × 2 factorial arrangement in order to assess the effects of the rearing system (outdoor v. indoor), diet (with corn grain silage v. without corn grain silage) and gender (barrows v. gilts) on performance, carcass traits, meat quality and intramuscular collagen (IMC) characteristics. During the trial period of 14 weeks, each group was housed in a pen of 12 m², and the outdoor-reared animals had access to a paddock of 24 m². Pigs were fed a diet computed according to standard requirements and supplied on a basis of 9% of metabolic weight (live weight^0.75). Pigs were slaughtered at 110.69 ± 0.85 kg. The rearing system did not significantly affect growth, hot and cold dressing, meat quality of m. longissimus lumborum or IMC. Outdoor pigs had less (P < 0.05) backfat thickness, slightly higher (P = 0.082) lean percent and a meat with lower pH and fat than the conventional system. In light of these results, alternative pig rearing systems with indoor space and free outdoor access could be an interesting production system for the pigs. Compared with the pigs fed diets with corn grain silage, those fed diets without corn had higher (P < 0.05) lean, ham percentage and IMC content, lower (P < 0.05) neck percentage but similar main tissue components of the ham and meat quality. Compared with the gilts, barrows were fatter and showed a meat with different physico-chemical traits, which was slightly more tender and had similar IMC properties.     

Serum and milk concentrations of leptin in gilts fed a high- or low-energy diet during gestation

Concentrations of leptin in serum and milk were assessed in gilts fed diets during gestation that differed in energy level. Beginning at day 45 and continuing throughout pregnancy, gilts received either a high-energy (6882 kcal metabolizable energy (ME) per day) or low-energy (5221 kcal ME per day) diet (n = 9 per group). All gilts had ad libitum access to a standard lactation diet throughout a 21 day lactation. During gestation, gilts consuming the high-energy diet gained more body weight (P < 0.01) and backfat thickness (P = 0.03) than gilts fed the low-energy diet; however, serum concentrations of leptin remained similar between groups (P = 0.35). Within 24 h after farrowing, gilts fed the high-energy diet had greater levels of leptin in serum and milk than gilts that consumed the low-energy diet during gestation (P < 0.07); Across treatments, backfat thickness and leptin levels in serum were positively correlated (r(2) = 0.51; P = 0.03). At weaning, backfat thickness (P < 0.07), but not body weights or serum and milk levels of leptin (P > 0.1), were greater for gilts fed the high-energy, versus the low-energy, diet during gestation. Gilts that were fed the low-energy diet during gestation consumed more feed during week 2 of lactation (P = 0.06). Our results suggest that altering the level of energy in the diets of gestating swine can influence circulating and milk concentrations of leptin, as well as feed consumption, during lactation.     

Effects of deep-bedded finishing system on market pig performance, composition and pork quality

The purpose of this study was to compare effects of finishing environment on growth performance, pork quality and lipid composition of pork. Environments compared were standard confinement (CON) and deep-bedded semi-outdoor systems. The deep-bedded method employed in the current study was the use of hoop structures. Hoops are large, tent-like shelters with cornstalks or straw for bedding. Gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of Hoop (n = 50) and CON (n = 18) environments. Gilts were fed a two-phase dietary sequence, ad libitum for 45 days. Six gilts per treatment were selected for carcass composition and quality evaluation. The experiment was replicated a total of five times. Pigs raised in the Hoop environment gained significantly less and required significantly more feed for growth than pigs raised in the CON environment. Carcasses from CON-finished pigs were significantly fatter at the 10th rib, which lowered carcass percentage fat-free lean(FFL) and they also had greater loin marbling scores compared with carcasses from Hoop-finished pigs (P < 0.05). Significant replication effects were noted on beginning weight, live weight, carcass weight, percentage FFL, backfat, lipid content and adipose firmness. Carcasses from Hoop pigs had lower proportions of palmitic acid (P < 0.05), and higher proportions of oleic and linoleic acid (P < 0.05) in the inner layer of adipose tissue. The proportion of saturated fatty acid was lower, and that of mono- and poly-unsaturated fatty acid was higher in the inner layer of the adipose tissue of Hoop pigs. Variations in fatty acid composition and lipid deposition may have been caused by environmental temperature, since decreases in environmental temperature accompanied compositional variation of the adipose, leading to higher proportions of monounsaturated fatty acid and lower proportions of saturated and polyunsaturated fatty acid in adipose tissue, regardless of treatment. Volatile profile analysis revealed that adipose tissue of Hoop pigs had significantly higher amounts of 3-butanal and heptanal compared with CON pigs, which may be related to the amount of oleic and linoleic acids composing the adipose tissue. These data indicate finishing pigs in hoop structures allows for exposure to fluctuating temperatures, which may influence the growth of pigs, as well as fatty acid composition and firmness of pork products.     

Effect of Dietary Mono- and Polyunsaturated Fatty Acids on the Fatty Acid Composition of Pigs' Adipose Tissues

In two experiments with growing-finishing pigs six different dietary fats were added to a conventional diet (control - C) to study the effects of dietary monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) on the fatty acid composition of backfat and kidney fat at similar amounts of double bonds in feed (Exp. 1:7% pork fat - PF, 4.95% olive oil - OO, 3.17% soybean oil - SO) or a constant amount of 5% of processed fats (Exp. 2: partially hydrogenated fat - SAT, fractionated pork fats: olein - OLE, stearin - STE). Compared with the control, PUFA were only slightly increased in backfat of pigs fed PF, OLE, STE or OO, although dietary PUFA intake was up to 70% higher. With SO PUFA were significantly increased in adipose tissues, predominantly at the expense of MUFA. Consequently, a non-linear relationship was found between PUFA intake and proportion in backfat. MUFA were incorporated at the expense of SFA, therefore, adipose tissues of OO fed animals were lowest in SFA. Despite comparable amounts of double bonds in feed (Exp. 1), the degree of unsaturation measured as fat score (sum of double bonds) was in the order SO > OO > PF > C. In contrast, the proportion of SFA was C > PF = SO > OO. Regarding the decisive role of SFA for fat consistency it may be concluded that MUFA should also be considered in feeding recommendations for pigs. Furthermore, in case of a high dietary supply of MUFA, a simple index of double bonds might not be sufficiently conclusive to judge pig fat quality.     

The effect of modified eros centre, outdoor raising or conventional group housing on breeding gilts and its effects on reproductive performance over four parities

The present study was conducted in a large Croatian "built up unit". The objective of the study was to determine if an indoor modified eros centre (MEC) compared to indoor or outdoor group housing of gilts, influenced the onset of puberty of gilts and the reproductive performance of the evaluated females (n = 783) over four parities. The gilts were from the same nucleus herd. Gilts of same age (140-150 days of age), body condition (body condition score of 3-4) and similar genetics (four-way cross females), during the same season (January to April 1999), were randomly divided at arrival into three groups and treated as follows:MEC gilts (n = 279): These were placed into indoor MEC pens in groups of 8-10. The gilts had continuous fenceline contact to boars (one boar to two groups of gilts, boars were changed daily) and to shortly weaned oestrous sows. Gilts were regrouped and dislocated at 10-day intervals. Outdoor gilts (n = 263): These were kept in groups of 8-10 on a large pasture (80-100 m2 per group). The animals had fenceline contact to mature boar for 5-10 min daily. Control indoor gilts (n = 241): These were housed indoors in large pens in groups of 8-10. The animals had fenceline contact to mature boars for 5-10 min daily. Each outdoor group had an insulated hut with straw bedding. All gilts were fed ad libitum with the same commercial diet. Housing gilts in MEC resulted in earlier (P < 0.001) onset of estrus (MEC: 174.8 +/- 2.4 days, indoor group housing: 207.6 +/- 4.1 days, outdoor group housing: 187.4 +/- 2.1 days) and lower (P < 0.001) farrowing rate to first service (MEC: 70.97%, indoor group housing: 89.73%, outdoor group housing: 89.62%). Farrowing rate of regularly returning MEC gilts to second service was 95.00%. First total-born litter size, first liveborn litter size, first wean-to-estrus interval (WEI), percent of sows bred after first weaning, second total-born litter size, second liveborn litter size, average third and fourth total-born and liveborn litter size, number of sows having four litters, number of litters per sow, total number of pigs per sow, total number of liveborn pigs per sow showed no significant differences between the groups. More (P < 0.05) sows were culled in outdoor group. Compared to MEC and outdoor housing, indoor housed sows suffered higher (P < 0.05) percentage of anoestrus.     

Effect of level of feed restriction during growth and/or fattening on fatty acid composition and lipogenic enzyme activity in heavy pigs

The influence of feeding system on growth performance, carcass characteristics, and fatty acids profile of subcutaneous backfat and lipogenic enzymes activity was studied. The following feeding systems were applied: HH: group of 12 pigs fed with a high feeding level during growth and fattening periods; HL: group of 12 pigs fed with a high feeding level during growth period and a low feeding level during fattening period; LH: group of 12 pigs fed with a low feeding level during growth period and a high feeding level during fattening period; LL: group of 12 pigs fed with a low feeding system during growth and fattening periods. The high and low feeding levels applied during growth and fattening periods were 70 and 35 g feed/kg live weight^0.75 (LW^0.75) day and 121 and 87 g feed/kg LW^0.75 day, respectively. The duration of the growth period was 163 days in all groups. The ages at slaughter of HH, HL, LH and LL pigs were approximately 383, 406, 439 and 503 days, respectively. The HH and LL pigs had the higher and lower average daily gain respectively, while the LH pigs presented the best feed conversion ratio during fattening period. At slaughter, the LL pigs had the higher value of loin width and the lower values of backfat thicknesses and Longissimus dorsi muscle intramuscular fat percentage (P<0.05). The subcutaneous backfat outer and inner layers from LH and LL pigs had a significantly (P<0.05) higher proportion of C18:1 n-9 and ΣMUFA (monounsaturated) acids than those from HH and HL pigs. The subcutaneous backfat inner layer from LL pigs had a lower C16:0 and ΣSFA (saturated) acids proportions than those from remaining groups of pigs. The activity of the fatty acid synthase (FAS) and glucose-6-phosphate dehydrogenase (G6PD) enzymes, measured in subcutaneous backfat, at the end of growing period was significantly (P<0.05) higher in pigs fed high feeding level during growing phase. An increase of feeding level during the fattening phase led to an increase in the activity of G6PD enzyme. In conclusion, a marked effect of feeding system was observed on pig productivity and fatty acid composition.     

Effects of chromium-loaded chitosan nanoparticles on growth, blood metabolites, immune traits and tissue chromium in finishing pigs

Effects of chromium-loaded chitosan nanoparticles (Cr-CNP) on growth performance, blood metabolites, immune traits, and tissue chromium in finishing pigs were investigated. A total of 160 crossbred barrows (66.06 ± 1.01 kg initial weight) were randomly divided into four groups, each group with four pens, ten pigs per pen. Pigs were fed on the same basal diet supplemented with 0 (the control), 100, 200, and 400 μg/kg Cr from Cr-CNP. All pigs were given free access to feed and water. Eight pigs from each treatment were selected to collect blood and tissue samples after 35 days on trial for analysis of blood metabolites and immune traits and tissue chromium. The results of feeding trial showed that there were no significant difference in growth performance between control and Cr-CNP-treated groups. The supplementation of Cr-CNP decreased serum glucose (P < 0.001) in a linear and quadratic manner. Serum immunoglobulins A and M were linearly increased in Cr-CNP-treated groups (P < 0.001), and serum complement 4 in Cr-CNP-treated groups was also linearly increased (P < 0.05). Cr-CNP supplementation linearly increased the chromium content in the blood, longissimus muscle, heart, liver, kidney, and pancreas (P < 0.001). These results suggested that dietary supplementation of Cr as Cr-CNP affects serum glucose, influences immune status, and increases the tissue chromium content of blood, muscle, and selected organs in finishing pigs.     

Effect of ractopamine and conjugated linoleic acid on performance of late finishing pigs

The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.     

Study of Oxidative Damage in Growing–Finishing Pigs with Continuous Excess Dietary Chromium Picolinate Intake

Chromium picolinate (CrPic) is a popular nutritional supplement; however, its safety has been questioned as it may be a source of oxidative stress that induces genotoxicity. The current work investigated the effect of excessive CrPic intake on oxidative damage in growing-finishing pigs. Thirty castrated male pigs, weighing approximately 30 kg each, were randomly divided into five groups and fed a diet with 0, 200, 800, 1,600, 3,200 microg of Cr/kg feed as CrPic for 80 days (approximately the entire growing-finishing period). High CrPic dose significantly decreased superoxide dismutase activity in serum at 80 days as well as the catalase activity in kidney (p < 0.05); however, compared to controls, malondialdehyde in tissue and serum, urinary 8-hydroxydeoxyguanosine level, and DNA strand breaks in liver and kidney had no notable differences (p > 0.05). These results suggested that long-term exposure to different doses of CrPic in feed did not increase the formation of biomarkers of oxidative damage in growing-finishing pigs. However, taking into account the changes of antioxidant enzymes activity, excessive dietary CrPic intake was not recommended in this study.     

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.     

Maternal backfat depth in gestating sows has a greater influence on offspring growth and carcass lean yield than maternal feed allocation during gestation

A commercial pig spends nearly half of its life in utero and its nutrition during this time can influence birth weight and postnatal growth. We hypothesised that postnatal growth is increased in pigs raised by sows with a high backfat depth and high level of energy intake during gestation compared with sows with a low backfat depth and low level of energy intake during gestation. This was tested in a 2×3 factorial design experiment with 2 factors for gilt backfat depth (Thin and Fat) and 3 factors for gestation feed allowance (Restricted, Control and High). Between d 25 and d 90 of gestation, Thin gilts (n=68; 12±0.6 mm P2 backfat) and Fat gilts (n=72; 19±0.6 mm P2 backfat) were randomly allocated, as individuals, to a gestation diet (6.19 g/kg lysine, 13.0 MJ DE/kg) at the following feed allowances: 1.8 kg/day (Restricted); 2.5 kg/day (Control) and 3.5 kg/day (High). For the remainder of gestation and during lactation all gilts were treated similarly. At weaning (day 28), 155 piglets were sacrificed and 272 were individually housed and followed through to slaughter (day 158). At day 80 of gestation, fasted Thin Restricted gilts had lower serum IGF-1 concentrations than Thin High or Thin Control fed gilts (P<0.001). Pigs born from Fat gilts had greater backfat depths (P<0.05), a lower lean meat yield (P<0.05) and were heavier (P<0.05) at slaughter than pigs born from Thin gilts. Gilt gestation feed allowance had only transitory effects on average daily gain and feed conversion efficiency and had no effect on pig weight at slaughter (P>0.05) or lean meat yield (P>0.05). In conclusion, gilts with a backfat depth of ~19 mm at insemination produced pigs that were heavier and fatter at ~158 days of age than those born from gilts with ~12 mm backfat depth at insemination. Maternal body condition during gestation had a more predominant influence on growth parameters of the offspring, such as weight at slaughter and backfat depth, than did feed level during gestation.     

Chemical composition and oxidative status of tissues from Iberian pigs as affected by diets: extensive feeding v. oleic acid- and tocopherol-enriched mixed diets

The present work was intended to analyse the chemical composition and oxidative stability of the muscle biceps femoris and adipose tissues from Iberian pigs fed different finishing diets: free-range feeding on grass and acorns in a 'Montanera' traditional system (MON), fed in confinement with a mixed diet containing high-oleic sunflower oil (115 g/kg of diet) and supplemented with 250 mg/kg α-tocopherol (HOVE), and fed in confinement with a tocopherol-non-supplemented control mixed diet (CON). Muscles from MON pigs contained significantly (P < 0.05) higher amounts of intramuscular fat than those from HOVE and CON pigs. Muscles from MON and HOVE pigs had significantly higher levels of α-tocopherol than muscles from CON pigs whereas free-range feeding provided significantly higher levels of γ-tocopherol to muscles from MON pigs than the experimental diets did to CON and HOVE pigs. Adipose tissues from MON and HOVE pigs contained significantly lower proportions of saturated fatty acids and significantly higher levels of oleic acid and monounsaturated fatty acids than those from CON pigs. Tissues from MON pigs contained significantly smaller levels of polyunsaturated fatty acids than those from CON and HOVE pigs. To a higher extent, feeding background affected the fatty acid composition of polar lipids from the muscle biceps femoris than that of neutral lipids. Tissues from MON pigs contained significantly smaller ω-6/ω-3 values than those from pigs fed mixed diets. Compared to tissues from CON pigs, those from MON and HOVE pigs exhibited a higher oxidative stability as a likely result of a most favourable fatty acid composition and the presence of higher tocopherol levels.