Next generation semiconductor based-sequencing of a nutrigenetics target gene (GPR120) and association with growth rate in Italian Large White pigs.

The GPR120 gene (also known as FFAR4 or O3FAR1) encodes for a functional omega-3 fatty acid receptor/sensor that mediates potent insulin sensitizing effects by repressing macrophage-induced tissue inflammation. For its functional role, GPR120 could be considered a potential target gene in animal nutrigenetics. In this work we resequenced the porcine GPR120 gene by high throughput Ion Torrent semiconductor sequencing of amplified fragments obtained from 8 DNA pools derived, on the whole, from 153 pigs of different breeds/populations (two Italian Large White pools, Italian Duroc, Italian Landrace, Casertana, Pietrain, Meishan, and wild boars). Three single nucleotide polymorphisms (SNPs), two synonymous substitutions and one in the putative 3'-untranslated region (g.114765469C > T), were identified and their allele frequencies were estimated by sequencing reads count. The g.114765469C > T SNP was also genotyped by PCR-RFLP confirming estimated frequency in Italian Large White pools. Then, this SNP was analyzed in two Italian Large White cohorts using a selective genotyping approach based on extreme and divergent pigs for back fat thickness (BFT) estimated breeding value (EBV) and average daily gain (ADG) EBV. Significant differences of allele and genotype frequencies distribution was observed between the extreme ADG-EBV groups (P < 0.001) whereas this marker was not associated with BFT-EBV.

Copy number variants in Italian Large White pigs detected using high-density single nucleotide polymorphisms and their association with back fat thickness.

The aim of this study was to identify copy number variants (CNVs) in Italian Large White pigs and test them for association with back fat thickness (BFT). Within a population of 12 000 performance-tested pigs, two groups of animals with extreme and divergent BFT estimated breeding values (EBVs; 147 with negative and 150 with positive EBVs) were genotyped with the Illumina Porcine SNP60 BeadChip. CNVs were detected with PENNCNV software. We identified a total of 4146 CNV events in 170 copy number variation regions (CNVRs) located on 15 porcine autosomes. Validation of detected CNVRs was carried out (i) by comparing CNVRs already detected by other studies and (ii) by semiquantitative fluorescent multiplex (SQFM) PCR of a few CNVRs. Most of CNVRs detected in Italian Large White pigs (71.2%) were already reported in other pig breeds/populations, and 82.1% of the CNV events detected by PENNCNV were confirmed by SQFM PCR. For each CNVR, we compared the occurrence of CNV events between the pigs of the high and low BFT EBV tails. Sixteen regions showed significance at P < 0.10, and seven were significant at P < 0.05 but were not significant after Bonferroni correction (Fisher's exact test). These results indicated that CNVs could explain a limited fraction of the genetic variability of fat deposition in Italian Large White pigs. However, it was interesting to note that one of these CNVRs encompassed the ZPLD1 gene. In humans, a rare CNV event including this gene is associated with obesity. Studies identifying CNVs in pigs could assist in elucidating the genetic mechanisms underlying human obesity.

Genome-Wide Association Study for Weight Loss at the End of Dry-Curing of Hams Produced from Purebred Heavy Pigs.

Dissecting the genetics of production traits in livestock is of outmost importance, both to understand biological mechanisms underlying those traits and to facilitate the design of selection programs incorporating that information. For the pig industry, traits related to curing are key for protected designation of origin productions. In particular, appropriate ham weight loss after dry-curing ensures high quality of the final product and avoids economic losses. In this study, we analyzed data (N = 410) of ham weight loss after approximately 20 months of dry-curing. The animals used for ham production were purebred pigs belonging to a commercial line. A genome-wide association study (GWAS) of 29,844 SNP markers revealed the polygenic nature of the trait: 221 loci explaining a small percentage of the variance (0.3-1.65%) were identified on almost all Sus scrofa chromosomes. Post-GWAS analyses revealed 32 windows located within regulatory regions and 94 windows located in intronic regions of specific genes. In total, 30 candidate genes encoding receptors and enzymes associated with ham weight loss (MTHFD1L, DUSP8), proteolysis (SPARCL1, MYH8), drip loss (TNNI2), growth (CDCA3, LSP1, CSMD1, AP2A2, TSPAN4), and fat metabolism (AGPAT4, IGF2R, PTDSS2, HRAS, TALDO1, BRSK2, TNNI2, SYT8, GTF2I, GTF2IRD1, LPCAT3, ATN1, GNB3, CMIP, SORCS2, CCSER1, SPP1) were detected.

Impact of innovative rearing strategies for the Italian heavy pigs: Technological traits and chemical composition of dry-cured hams.

To explore the influence of 4 feeding strategies on dry-cured ham quality, 336 barrows and gilts (3 batches, 112 pigs/batch) of 90 kg body weight (BW), were divided into 4 groups and housed in 8 pens with automated feeders. In the control group (C), the pigs were fed restrictively medium-protein feeds and slaughtered at 170 kg BW (SW) and 265 d of slaughter age (SA). With the older age (OA) treatment, the pigs were restrictively fed low protein feeds and slaughtered at 170 kg SW and 278 d SA. The other two groups were fed ad libitum high protein feeds, the younger age (YA) group was slaughtered at 170 kg SW and 237 d SA, the greater weight (GW) at 265 d of SA and 194 kg SW. The hams were dry-cured and seasoned for 607 d, weighed before and after seasoning and deboning. Sixty hams were sampled and sliced. The lean and the fat tissues were separated and analyzed for proximate composition and fatty acid profile. The model of analysis considered sex and treatment as fixed factors. With respect to C: i) OA lowered the ham weight, the lean protein content, increased marbling and decreased the PUFA proportion in intramuscular and subcutaneous fat; ii) YA hams had thicker fat cover with lower PUFA in intramuscular and subcutaneous fat; iii) GW increased the deboned ham weight, fat cover depth and marbling, reduced PUFA in intramuscular and subcutaneous fat, without alteration of the lean moisture content. Sex had a negligible impact.

Transcriptomic Profiling of Subcutaneous Backfat in Castrated and Intact Alentejano Pigs Finished Outdoors with Commercial and Fiber-Rich Diets.

In this work, we studied the backfat transcriptome of surgically castrated (C), intact (I) and intact fed an experimental diet (IE) outdoor-reared male Alentejano (AL) pigs. The experimental diet was a high-fiber diet with locally produced legumes and by-products associated with a boar taint reduction effect. At slaughter (~160 kg), backfat samples were collected for total RNA sequencing. Intact pigs presented leaner carcasses, more total collagen, and more unsaturated intramuscular fat content than C animals. A total of 2726 differentially expressed genes (DEGs, |log2 FC|> 0.58, q < 0.05) were identified between C and I with overexpressed genes related to muscular activity (MYH1, ACTA1) or collagen metabolism (COL1A1, COL1A2) in I pigs. Between C and IE, 1639 DEGs of genes involved in lipidic metabolism (LEP, ME1, FABP4, ELOVL6) were overexpressed in C. Finally, only 28 DEGs were determined between I and IE. Clustering results indicated a drastic influence of the testis in the transcriptome of subcutaneous fat of AL pigs, while the diet had a marginal effect. Diet can reduce stress by increasing satiety in animals, and could have induced an increase of skatole degradation due to the higher expression of the CYP2A19 gene in the IE group.

Impact of Rearing Strategies on the Metabolizable Energy and SID Lysine Partitioning in Pigs Growing from 90 to 200 kg in Body Weight.

The current nutrient recommendations focus on pigs fed ad libitum up to 140 kg in body weight (BW). It remains unclear whether this applies to pigs weighing above 140 kg in BW under different rearing conditions. This study aimed to estimate protein (Pd) and lipid (Ld) depositions and the metabolizable energy (ME), standardized ileal digestible lysine (SID lysine) requirement and partitioning in 224 C21 Goland pigs (90−200 kg in BW). The control pigs (C) received diets limiting ME up to 170 kg in slaughter weight (SW) at 9 months of age (SA); older (OA) pigs had restricted diets limiting ME and SID lysine up to 170 kg in SW at >9 months SA; younger (YA) pigs were fed nonlimited amounts of ME and SID lysine up to 170 kg in SW at <9 months SA; and greater weight (GW) pigs were fed as the YA group, with 9 months SA at >170 kg in SW. The estimated MEm averaged 1.03 MJ/kg0.60. An 11% increase in MEm was observed in OA pigs compared to the controls. Energy restriction had negligible effects on the estimated MEm. The marginal efficiency of SID lysine utilization for Pd averaged 0.725, corresponding to a SID lysine requirement of 9.8 g/100 g Pd.

Differences in carcass chilling rate underlie differences in sensory traits of pork chops from pigs with heavier carcass weights.

Pork hot carcass weights (HCW) have been increasing 0.6 kg per year, and if they continue to increase at this rate, they are projected to reach an average weight of 118 kg by the year 2050. This projection in weight is a concern for pork packers and processors given the challenges in product quality from heavier carcasses of broiler chickens. However, previous work demonstrated that pork chops from heavier carcasses were more tender than those from lighter carcasses. Therefore, the objective was to determine the effects of pork hot carcass weights, ranging from 90 to 145 kg with an average of 119 kg, on slice shear force and sensory traits of Longissimus dorsi chops when cooked to 63 or 71 °C, and to assess if differences in chilling rate can explain differences in sensory traits. Carcasses were categorized retrospectively into fast, medium, or slow chilling-rates based on their chilling rate during the first 17 h postmortem. Loin chops cut from 95 boneless loins were cooked to either 63 or 71 °C and evaluated for slice shear force and trained sensory panel traits (tenderness, juiciness, and flavor) using two different research laboratories. Slopes of regression lines and coefficients of determination between HCW and sensory traits were calculated using the REG procedure in SAS and considered different from 0 at P ≤ 0.05. As hot carcass weight increased, chops became more tender as evidenced by a decrease in SSF (63 °C ß = -0.0412, P = 0.01; 71 °C ß = -0.1005, P < 0.001). Furthermore, HCW explained 25% (R2 = 0.2536) of the variation in chilling rate during the first 5 h of chilling and 32% (R2 = 0.3205) of the variation in chilling rate from 5 to 13 h postmortem. Slow- and medium-rate chilling carcasses were approximately 12 kg heavier (P < 0.05) than fast chilling carcasses. Slice shear force of chops cooked to 63 and 71 °C was reduced in slow and medium chilling compared with fast chilling carcasses. Carcass temperature at 5 h postmortem explained the greatest portion of variation (R2 = 0.071) in slice shear force of chops cooked to 63 °C. These results suggest that carcasses tend to chill slower as weight increases, which resulted in slight improvements in sensory traits of boneless pork chops regardless of final degree of doneness cooking temperature.

Pork carcass weights have increased year over year for at least the past 25 yr. The poultry industry has experienced similar increases in carcass weights in the recent past. The increases in broiler carcass weights have resulted in detrimental impacts on quality. Contrary to the poultry industry, increases in pork carcass weights have resulted in a general improvement in pork quality, including tenderness. The underlying cause of these improvements has not been explained. In the present study, chilling rate was associated with carcass weights, particularly during the first 5 h postmortem. In fact, carcass temperature measured in the Longissimus dorsi muscle at 5 h postmortem was the most predictive of instrumental tenderness values when boneless pork chops were cooked according to UDSA guidelines for whole-muscle pork products. The metabolic conversion of muscle to meat is most active during this initial chilling period. Therefore, chilling rate, which is associated with carcass weight, may be influencing the conversion of muscle to meat and provide some explanation as to why heavy carcasses result in more tender pork chops.

Prevalence of fibrinous pericarditis in heavy pigs (170 kg) and its association with other pluck lesions at slaughter inspection.

This study determined the prevalence of fibrinous pericarditis and its correlation with other pluck lesions in 658 batches of pigs from 236 intensive farms located in Northern Italy over a 12-month period. All pigs were slaughtered at 170 kg, and a total 57,943 plucks (approximately 90 pigs/batch) were individually assessed for the presence of fibrinous pericarditis, pneumonia, pleuritis, and liver milk spots. There was no seasonal variation in the prevalence of plucks with fibrinous pericarditis and annual mean prevalence was 5.6% (range, 0-26.3% at batch level; median, 4.71%). Farm of origin, evaluated as a random effect, accounted for 17.7% batch variation. Batches with a high prevalence of fibrinous pericarditis (≥7.7%) had higher prevalences of pleural, pulmonary, and liver lesions than those with low-middle prevalence of pericarditis; high prevalence of pericarditis was predictive of pluck lesions (P < 0.001). There was a highly significant association between fibrinous pericarditis and severe pleuritis, and 55% of plucks with the highest score for pleuritis also had ongoing fibrinous pericarditis, with a positive correlation at batch level (r2 = 0.52; P < 0.001). The co-existence of pericarditis and pleuritis (73.5% of all pericarditis cases) suggests that pleuritis plays a role in the pathogenesis of pericarditis. Based on the prevalence fibrinous pericarditis, and the role of pleuritis as a potential comorbidity, abattoir data on pluck lesions with accompanying farm history, could aid the interpretation and management of on-farm health problems, and inform diagnostic protocols.

Literature Review on the Pre-Slaughter Welfare of Italian Heavy Pigs.

This work provides a narrative review of the available information on the welfare of Italian heavy pigs in the pre-slaughter phase (transport, lairage, and stunning). The meat from these pigs is used for specific PDO (Protected Designation of Origin) products, and the production rules for these specialties require higher body weight (160-170 kg) and age (in general more than 9 months) at slaughter than in most other countries. This may lead to specific behavioral and physiological needs of pigs. The present paper summarizes the main research findings and knowledge gaps for each of the pre-slaughter phases. Studies are presented according to the four principles of the Welfare Quality assessment protocol (good feeding, good housing, good health, and appropriate behavior). The results of the literature review indicate a lack of knowledge on several aspects. Most of studies were carried out in a single slaughterhouse, making it difficult to identify risk factors and confounding effects. Moreover, animal-based measures were assessed using different protocols, reducing the possibility of comparison across studies. These findings may serve as a basis for the development of specific research studies and policies aimed at enhancing the animal welfare level and the ethical attributes of this renowned production, also in accordance with consumers' expectations.

Predictivity of Antemortem Findings on Postmortem Inspection in Italian Heavy Pigs Slaughterhouses.

Pigs slaughtered in European abattoirs must be submitted to antemortem inspection (AMI) and postmortem inspection (PMI), as required by the current European legislation in the matter of official controls. AMI and PMI are equally essential to guarantee food safety and to monitor swine health and welfare. However, little is known about the ability of AMI to predict conditions that are possibly found during PMI. In this study, such a correlation was explored together with the assessment of conditions typically found during AMI and PMI in heavy pigs slaughtered in two Italian slaughterhouses. An assessment scheme containing 13 variables for AMI and 34 lesions for PMI was used for the scope. The herd size was also considered as a variable and included in the study. A total of 24,510 pigs and 30,961 pigs were assessed during AMI and PMI, respectively. The most common conditions found were manure on the body covering more than 30% of the body (dirt >30%) and pluck lesions ('pleurisy', 'pericarditis', and 'pneumonia') for AMI and PMI, respectively. A significant correlation (p < 0.05) between some antemortem (AM) findings and postmortem (PM) conditions was found. In particular, the AM conditions 'dirt >30%'and 'skin lesions' were positively related with PM conditions 'skin wounds' and 'dermatitis', while the complexes of respiratory and kidney lesions were predicted only by the condition 'dirt >30%'. The variable 'standardized herd size' was negatively associated with 'milk spot liver' and positively associated with 'arthritis/bursitis'. The results of this study show that findings reported during AMI can potentially be used to predict certain conditions found in pigs at PMI. These data can be useful for the competent authorities in characterizing swine farms using a risk-based approach and in developing systems and specific plans for official controls.

Knowledge and Perspectives on the Welfare of Italian Heavy Pigs on Farms.

This review aims to give an overview of the most significant available information on welfare issues of Italian heavy pigs on farms. These animals, whose meat is used to produce typical products, are characterized by much higher body weights and age at slaughter (approximately 160-170 kg, and 9 months of age) than most pigs reared in Europe, resulting in peculiar behavioral and rearing-related needs. To highlight the main findings and the areas in which additional research is needed, the paper was organized by allocating the studies on the basis of the Welfare Quality four principles framework, i.e., good feeding, good housing, good health, and appropriate behavior. The results indicate the possibility of improvement with regard to the management of feeding, watering, and some environmental parameters (light, thermal comfort, enrichments) and a lack of knowledge on the actual space requirements (and a corresponding regulatory gap). Moreover, deficiencies concerning the prevalence of injuries and disease and the relationship between lesions observed post-mortem and rearing conditions needs to be addressed. Lastly, the absence of research concerning the evaluation of the emotional state of animals has been highlighted. It is hoped that these findings will, in the future, serve as a basis for the development of specific policies for these animals in order to increase the ethical value of the entire production chain, in accordance with consumers' demand and expectation for high animal welfare standards.

Behavior and Welfare of Undocked Heavy Pigs Raised in Buildings with Different Ventilation Systems.

The present study aimed to evaluate animal welfare of pigs from the same farm, raised with two ventilation systems. The study involved 60 pens of fattening pigs, raised in two buildings: one naturally ventilated (NV) and the other mechanically ventilated (MV). Pigs were assessed on three observation days: at 40 kg (T1), 100 kg (T2), and 160 kg (T3) of live weight. Animal-based measures were used such as qualitative behavioral analysis (QBA), behavioral measures (BMs), and lesion and health measures (LHMs). Housing conditions (HCs) measured at each observation day were the number of pigs per pen, space allowance, temperature, light, and CO2. The association study was performed using a general linear model and analysis of variance. Ventilation effect was analyzed by performing computational fluid dynamics. Results showed that overall pigs raised in the MV were in a more positive affective state. Despite that, with hot temperatures, the higher occurrence of pig soiling indicated heat stress in pigs and consequent welfare impairment. The higher frequency of pigs showing dog sitting behavior at T2 and T3 suggest welfare worsening in the last phases of fattening. The study concludes that ventilation system influences animal behavior and overall animal welfare, especially during the warmer season.

Effects of space allowance and marketing strategy on growth performance of pigs raised to 165 kg.

A total of 976 pigs (PIC 327 × Camborough; PIC, Hendersonville, TN; initially 22.0 ± 1.53 kg body weight [BW]) were used in a 160-d growth study to evaluate the effects of increasing space allowance and varying marketing strategies on growth performance of pigs raised to market weights of ~165 kg. Pens of pigs were blocked by location within the barn and allotted to one of six treatments. Pen served as the experimental unit, and there were eight replicate pens per treatment. The first four treatments consisted of increased initial stocking density and did not utilize topping strategies: (1) 14 pigs/pen (1.17 m2/pig), (2) 17 pigs/pen (0.97 m2/pig), (3) 20 pigs/pen (0.82 m2/pig), and (4) 23 pigs/pen (0.71 m2/pig). The fifth treatment began with 25 pigs/pen (0.66 m2/pig) and had four marketing events with the heaviest 3 pigs/pen removed on day 93, and additional pigs removed to a common inventory of 20 pigs/pen on day 122 and 17 pigs/pen on day 147 with final marketing on day 160. The final treatment began the experiment with 23 pigs/pen (0.71 m2/pig) with three marketing events to achieve a common inventory of 20 pigs/pen on day 108 and 17 pigs/pen on day 147. Pens of pigs were weighed and feed disappearance measured on days 0, 55, 93, 108, 122, 135, 147, and 160. As space allowance decreased from 1.17 to 0.71 m2/pig via increased initial pen inventory (treatments 1 to 4), overall average daily gain (ADG) and average daily feed intake (ADFI) decreased (linear, P < 0.001), while gain:feed ratio (G:F) did not differ (P > 0.05). The treatments with multiple marketing events were compared with each other and with the treatment that began with 0.71 m2/pig and only marketed once at the end of the study. Overall ADG and ADFI were not different (P > 0.05) among these three treatments. Marketing pigs three or four times improved (P < 0.05) G:F compared with the treatment that began the study with 0.71 m2/pig and marketed only once. Reducing floor space allowance for heavy weight pigs decreased intake, which resulted in lower growth rate and final BW, with these reductions occurring before the critical k-value was reached. Total weight gain per pen was maximized with the lowest space allowance and the multiple marketing treatments. Thus, strategic use of pig removals prior to final marketing may allow producers to maximize both number of pigs and total weight marketed through a barn when feeding to heavy weights.

Prediction of dry-cured ham weight loss and prospects of use in a pig breeding program.

Large ham weight losses (WL) in dry-curing are undesired as they lead to a loss of marketable product and penalise the quality of the dry-cured ham. The availability of early predictions of WL may ease the adaptation of the dry-curing process to the characteristics of the thighs and increase the effectiveness of selective breeding in enhancing WL. Aims of this study were (i) to develop Bayesian and Random Forests (RFs) regression models for the prediction of ham WL during dry-curing using on-site infrared spectra of raw ham subcutaneous fat, carcass and raw ham traits as predictors and (ii) to estimate genetic parameters for WL and their predictions (P-WL). Visible-near infrared spectra were collected on the transversal section of the subcutaneous fat of raw hams. Carcass traits were carcass weight, carcass backfat depth, lean meat content and weight of raw hams. Raw ham traits included measures of ham subcutaneous fat depth and linear scores for round shape, subcutaneous fat thickness and marbling of the visible muscles of the thigh. Measures of WL were available for 1672 hams. The best prediction accuracies were those of a Bayesian regression model including the average spectrum, carcass and raw ham traits, with R2 values in validation of 0.46, 0.55 and 0.62, for WL at end of salting (23 days), resting (90 days) and curing (12 months), respectively. When WL at salting was used as an additional predictor of total WL, the R2 in validation was 0.67. Bayesian regressions were more accurate than RFs models in predicting all the investigated traits. Restricted maximum likelihood (REML) estimates of genetic parameters for WL and P-WL at the end of curing were estimated through a bivariate animal model including 1672 measures of WL and 8819 P-WL records. Results evidenced that the traits are heritable (h2 ± SE was 0.27 ± 0.04 for WL and 0.39 ± 0.04 for P-WL), and the additive genetic correlation is positive and high (ra = 0.88 ± 0.03). Prediction accuracy of ham WL is high enough to envisage a future use of prediction models in identifying batches of hams requiring an adaptation of the processing conditions to optimise results of the manufacturing process. The positive and high genetic correlation detected between WL and P-WL at the end of dry-curing, as well as the estimated heritability for P-WL, suggests that P-WL can be successfully used as an indicator trait of the measured WL in pig breeding programs.

The effect of protein restriction during the growing period on carcass, meat and fat quality of heavy barrows and gilts.

Nutritional strategies are being researched in pigs to increase fatness and then to improve quality of dry-cured products. A total of 160 Duroc×(Landrace×Large White) pigs, 50% barrows and 50% gilts, were used in a trial. During the growing period (73-118d of age), four feeds were formulated with decreasing levels of crude protein (CP; 21.6, 17.7, 14.7 and 13.5%) to achieve 1.10, 0.91, 0.78 and 0.52% of total Lysine, respectively. From 118d until slaughter, at 123kg (183, 181, 178 or 192d of age, respectively), a common diet was provided (17.7% CP and 0.91% Lysine). Barrows had fatter carcasses than gilts but intramuscular fat (IMF) proportion was similar for both. Dietary CP restriction promoted wider backfat depth and pork with higher IMF percentage which was more monounsaturated and less polyunsaturated. We conclude that CP restriction during the grower period improves desirable carcass and meat traits in barrows and gilts intended for dry-cured products.

Suitability of a Salmonella control programme based on serology in slaughter heavy pigs.

The key component of most European pig Salmonella control programmes is the classification of herds according to seroprevalence at slaughter. The objectives of this study were to estimate the true Salmonella seroprevalence, and investigate the association between the true status of infection and serology in slaughter heavy pigs. Blood of 3340 pigs was collected and tested with ELISA. From 385 pigs, also lymph nodes and cecal content were collected for bacteriology. Analysis was performed in a Bayesian framework. Results showed that a large proportion of pigs was serologically positive (herd seroprevalence 93% and within-herd seroprevalence higher than 81% in half of herds at cut-off 10 OD%). The association between the true status of infection and serology was not significant, and therefore the classification of heavy pig herds according to seroprevalence at slaughter would not be suitable to reduce the risk of introducing Salmonella into the food chain.

Direct and social genetic effects on body weight at 270 days and carcass and ham quality traits in heavy pigs.

The aims of this study were to estimate covariance components for BW at 270 d (BW270) and carcass and ham quality traits in heavy pigs using models accounting for social effects and to compare the ability of such models to fit the data relative to models ignoring social interactions. Phenotypic records were from 9,871 pigs sired by 293 purebred boars mated to 456 crossbred sows. Piglets were born and reared at the same farm and randomly assigned at 60 d of age to groups (6.1 pigs per group on average) housed in finishing pens, each having an area of 6 m(2). The average additive genetic relationship among group mates was 0.11. Pigs were slaughtered at 277 ± 3 d of age and 169.7 ± 13.9 kg BW in groups of nearly 70 animals each. Four univariate animal models were compared: a basic model (M1) including only direct additive genetic effects, a model (M2) with nonheritable social group (pen) effects in addition to effects in M1, a model (M3) accounting for litter effects in addition to M2, and a model (M4) accounting for social genetic effects in addition to effects in M3. Restricted maximum likelihood estimates of covariance components were obtained for BW270; carcass backfat depth; carcass lean meat content (CLM); iodine number (IOD); and linoleic acid content (LIA) of raw ham subcutaneous fat; subcutaneous fat depth in the proximity of semimembranosus muscle (SFD1) and quadriceps femoris muscle (SFD2); and linear scores for ham round shape (RS), subcutaneous fat (SF), and marbling. Likelihood ratio tests indicated that, for all traits, M2 fit the data better than M1 and that M3 was superior to M2 except for SFD1 and SFD2. Model M4 was significantly better than M3 for BW270 (P < 0.001) and CLM, IOD, RS, and SF (P < 0.05). The contribution of social genetic effects to the total heritable variance was large for CLM and BW270, ranging from 33.2 to 35%, whereas the one for ham quality traits ranged from 6.8 (RS) to 11.2% (SF). Direct and social genetic effects on BW270 were uncorrelated, whereas there was a negative genetic covariance between direct and social effects on CLM, IOD, RS, and SF, which reduced the total heritable variance. This variance, measured relative to phenotypic variance, ranged from 21 (CLM) to 54% (BW270). Results indicate that social genetic effects affect variation in traits relevant for heavy pigs used in dry-cured hams manufacturing. Such effects should be exploited and taken into account in design of breeding programs for heavy pigs.

Effect of dietary inclusion of whole ear corn silage on stomach development and gastric mucosa integrity of heavy pigs at slaughter.

The effect of dietary inclusion of whole ear corn silage on stomach development and on the incidence of gastric lesions was studied in heavy pigs. Three groups of 14 castrated male pigs were fed a control cereal-based diet and two diets containing whole ear corn silage (15% or 30% DM) from 90 kg bodyweight to slaughter at 170 kg. The diets with whole ear corn silage increased the amount of neutral detergent fibre in the stomach contents, the weight of the organs and the area of the pyloric region. Follicular gastritis was significantly lower and gastritis less severe in pigs fed the whole ear corn silage diets than pigs fed the control diet. The inclusion of whole ear corn silage in the diet influenced the development of the stomach and reduced the incidence of gastritis in heavy pigs.

Live performance, carcass quality, and economic assessment of over 100kg slaughtered pigs / Desempenho, qualidade de carcaça e avaliação econômica de suínos abatidos acima de 100kg

Recent genetic improvement has developed pigs with maximum potential for protein deposit at higher weights; however, their optimal slaughter weight still needs to be determined. The objective of the study was to evaluate live performance, carcass traits, and economic viability of 417 Agroceres PIC pigs slaughtered with 100, 115, 130, and 145kg live weight. Pigs were reared in pens with 10-11 barrows and gilts each, offered a feed allowance of 2.8kg/pig/day until the following slaughter weights (SW): 99.65±0.82kg, 118.53±0.98kg, 133.97±1.17kg, and 143.90±1.24. There was no interaction between sex and SW (P>0.05). Backfat thickness, fat area, and loin eye area linearly increased with SW (P<0.001; R2: 70.12-77.44%), and carcass yield increased in a quadratic manner (P<0.001; R²=24.66%). Lean yield was not affected (P>0.05), and feed conversion ratio (R²=43.29%) linearly worsened with SW (P<0.001), but the effect of SW on live production cost (R$/kg) was quadratic, with the minimum point at 134.8kg. It was concluded that, under the applied management, increasing SW results in larger amount of lean tissue with no change in its yield and little effect on growth performance.

A evolução das linhagens sintéticas de suínos propiciou a obtenção de animais com potencial máximo de deposição proteica em pesos superiores; entretanto o peso ótimo de abate dessas linhagens não é conhecido. O objetivo do estudo foi avaliar o desempenho, características de carcaça e avaliação econômica de 417 suínos da linhagem Agroceres PIC abatidos com 100, 115, 130 e 145kg de peso vivo. Os suínos foram criados em baias com 10-11 machos ou fêmeas, com fornecimento programado de 2,8kg de ração por animal, por dia, a partir de 80kg até os pesos de abate (PA) de 99.65±0.82kg, 118.53±0.98kg, 133.97±1.17kg, e 143.90±1.24. Não houve interação entre sexo e PA (P>0,05). A espessura de toucinho, área de gordura e área de olho de lombo aumentaram linearmente com o PA (P<0,001; R² entre 70,12 e 77,44%), e o rendimento de carcaça aumentou de forma quadrática (P<0,001; R²=24,66%). A porcentagem de carne magra não foi afetada (P>0.05) e a conversão alimentar (R²=43,29%) apresentou discreta piora linear com o PA (P<0,001), mas o efeito sobre o custo de produção (R$/Kg) foi quadrático, com ponto de mínima aos 134,85kg. Conclui-se que, com o manejo utilizado, a elevação do PA resulta em aumento na quantidade de carne produzida sem alteração no seu rendimento e apresenta pouco efeito sobre o desempenho.