Relationships between carcass quality parameters and genetic types

Pork belly quality variation and its association with fatness level

Belly is a very popular pork cut composed of different layers of fat and muscle tissue. This work aims to investigate the effect of belly fatness on the morphological, mechanical (firmness) and compositional characteristics of fresh pork bellies and the distribution of the fat within the belly slice. A total of 182 bellies, selected to ensure variability of fatness, sexes and genotypes, were scanned by computed tomography (CT) to determine the fat content which, together with the genotype, led to the formation of 5 classes: F1 class below 26%, F2 class from 26% to 33.9%, and F3 class above 33.9% of fat content from common commercial crossbred pigs; F4 class with an average fatness of 47.3% from pure Duroc pigs; and last, F5 class with 62.6% average fat content from Iberian×Duroc pigs. The distribution of the fat in the central belly slice obtained by CT revealed important differences by region although the fat content was proportional to the overall fatness of the belly. Both belly weight and belly firmness increased with higher fatness. In bellies from common commercial pigs, an increase of SFA and MUFA and a decrease of PUFA as fatness increased was observed. This study highlights variations in belly characteristics among different fat classes, indicating considerable differences in the quality of bellies currently available in the market. This may influence producers and consumers acceptability such that fat content could be considered as a quality criterion to pre-classify bellies and better match the raw product with its final destination.

Comparison of Growth Performance, Carcass Properties, Fatty Acid Profile, and Genes Involved in Fat Metabolism in Nanyang and Landrace Pigs

This study compared the growth, carcass properties, fatty acid profile, lipid-producing enzyme activity, and expression pattern of genes involved in fat metabolism in Nanyang and Landrace pigs. In the study, 32 Nanyang (22.16 ± 0.59 kg) and 32 Landrace barrows (21.37 ± 0.57 kg) were selected and divided into two groups, each with eight pens and four pigs per pen. The trial period lasted 90 days. The findings showed that the Nanyang pigs had lower average daily weight gain and lean percentage and higher average backfat thickness and lipogenic enzyme activities, including for acetyl-CoA carboxylase, glucose-6-phosphate dehydrogenase, malic enzyme, and fatty acid synthase, than the Landrace pigs. A total of 14 long-chain fatty acids were detected using HPLC-MS, in which it was found that the levels of C14:0, C18:1n-9, C20:1n-9, C20:4n-6, and MUFA were up-regulated and C18:2n-6, C18:3n-3, PUFA n6, n3/n6, and total PUFA were down-regulated in the Nanyang pigs. Moreover, the mRNA levels for genes involved in fat metabolism, ME1, FAS, and LPL, were higher and the expression of SREBP1 mRNA was lower in the Nanyang pigs. Our results suggest genetic differences between the pig breeds in terms of growth, carcass traits, lipogenic enzyme activities, fatty acid profile, and the mRNA expression of genes involved in fat metabolism in subcutaneous fat tissue, which may provide a basis for high-quality pork production. Further studies are needed to investigate the regulation of lipid metabolism.

Non-destructive evaluation of carcass and ham traits and meat quality assessment applied to early and late immunocastrated Iberian pigs

Castration is a common practice in Iberian pigs due to their advanced age and high weight at slaughter. Immunocastration (IC) is an alternative to surgical castration that influences carcass and cut fatness. These traits need to be evaluated in vivo and postmortem. The aims of the present work were (a) to determine the relationship between ham composition measured with computed tomography (CT) and in vivo ultrasound (US) and carcass fat thickness measurements, (b) to apply these technologies to early (EIP) and late (LIP) immunocastrated Iberian pigs in order to evaluate carcass fatness and ham tissue composition and (c) to assess meat quality on these animals and to find the relationships between meat quality traits (namely, intramuscular fat (IMF)) and fat depot thicknesses. For this purpose, 20 purebred Iberian pigs were immunocastrated with three doses of Improvac ®, at either 4.5, 5.5 and 9 or 11, 12 and 14 months of age (EIP or LIP; respectively; n = 10 each) and slaughtered at 17 months of age. Fat depots were evaluated in vivo by US, in carcass with a ruler and in hams by CT. Carcass and cut yields, loin meat quality and loin acceptability by consumers were determined. Also, IMF was determined in the loin and three muscles of the ham. Carcass weight was 14.9 kg heavier in EIP vs LIP, and loin backfat thickness (US- and ruler-measured) was also greater in EIP. Similarly, CT-evaluated ham bone and fat contents were greater and smaller for EIP vs LIP, respectively. Loin and ham IMF were also greater in EIP, but the other meat quality parameters were similar. The acceptability of meat by consumers was high and it did not differ between IC protocols. Correlations between several fat depots measured with the different technologies were high. In conclusion, all these technologies allowed fat depot measurements, which were highly correlated despite being obtained at different anatomical locations.

The Implications of Nutritional Strategies that Modify Dietary Energy and Lysine for Growth Performance in Two Different Swine Production Systems

Simple Summary

Reducing dietary energy is a common practice for dealing with the price volatility of high energy sources, such as fats and oils, which are the costliest constraints in swine feed formulation. Theoretically, pigs can overcome a reduced energy density by increasing feed intake; however, as other factors like fibrous ingredients limit feed intake physically rather than metabolically, reducing dietary energy could also entail a lower energy intake. The expected effect on feed intake also influences lysine intake, and therefore, when NE trials are conducted, it is necessary to ensure that lysine is not a limiting factor for growth. In the present work, the effects of two dietary energy and lysine levels were tested in a factorial arrangement. The same approach of different levels was analyzed in two different swine production systems targeting different carcass traits. The experiment showed that in one system, reducing energy density did not impair growth; however, in the other system, it limited growth slightly by limiting fat deposition. Although reducing energy density increased feed intake, pigs could not reach a similar energy intake, and consequently were more efficient using energy for growth.

Abstract

This work aimed to determine the impacts of lowering dietary net energy (NE) density in two swine production systems that produce pigs with different carcass traits. To ensure that dietary lysine was not limiting growth, two studies were conducted in a 2 × 2 factorial arrangement with NE and standardized ileal digestible lysine (SID Lys) as experimental factors. A total of 1248 pigs were used in each study, Pietrain (Exp. 1, males non-castrated) or Duroc (Exp. 2, males castrated) sired. Reducing NE resulted in a greater feed intake; however, this was not sufficient to reach the same NE intake. While in Exp. 1 a 3.2% lower NE intake did not impair average daily gain (ADG; p = 0.220), in Exp. 2 a 4.7% lower NE intake reduced ADG by 1.4% (p = 0.027). Furthermore, this effect on ADG entailed a reduced ham fat thickness (p = 0.004) of the first marketed pigs. Increasing SID Lys only had a positive effect in Exp. 1, but no significant interaction between NE and SID Lys was reported (p ≥ 0.100). Therefore, dietary NE can be reduced without impairing growth performance when pigs can increase feed intake sufficiently, and thus, limit energy deficiencies.

Carcass gain per kg feed intake: developing a stakeholder-driven benchmark for comparing grow-finishing pig performance

Feed conversion ratio (FCR) in grow-finishing pigs is one of the most important determinants of pig farm profitability and production efficiency. In its simplest form, FCR represents the amount of feed used per unit weight gain of the pig. Yet, this approach entails various limitations hampering its practical applicability such as availability of accurate data and large variation in ways to adapt FCR values for different starting and end weight as well as mortality rates. Various stakeholders are using their own formulas to determine FCR creating a 'definition nonconformity' when comparing FCRs among farms. This study aimed to optimize the calculation of FCR through the use of participatory qualitative research. A multidisciplinary research group of 9 persons (animal scientists, veterinarians and agricultural economists) and a consulting group of 31 stakeholders (representing the Flemish primary sector, feed industry, pharma, genetic companies, large retailers, academia and policy institutions) were involved. The decision problem analysis started with a literature review, followed by 25 in-depth interviews and their analyses (NVivo 11™). This led to an additional literature review and the formation of focus (expert) groups that helped to formulate preliminary FCR formulas. Revision rounds between the research team and the stakeholders further fine-tuned the formulas with the final result being two distinct complimentary formulas that are fit for purpose. Both refer to carcass gain per kg feed intake (plain (CGF) and standardized (CGFstandardized)). The first formula (CGF), namely ${{{\it{number \, delivered \, pigs}} \times {\it{average \, warm \, carcass \, weight}} - {\it{number \, stocked \, piglets}} \times {\it{average \, piglet \, weight}} \times {\it{piglet \, carcass \, yield}}} \over {{\it{feed \, consumption}}}}$ is an objective representation of the animals' performance. The second formula (CGFstandardized) was developed for farm benchmarking, incorporating a seven-step standardization process that corrects for mortality and 'standardizes' for a fixed (yet fictive) live weight trajectory of 25 to 115 kg. This second formula allows to compare farms (or batches of fattening pigs) with different weight trajectories and different mortality rates. A webtool was designed to ease this standardization process (https://varkensloket.be/tools/CGF).

Automatic ham classification method based on support vector machine model increases accuracy and benefits compared to manual classification

The thickness of the subcutaneous fat (SFT) is a very important parameter in the ham, since determines the process the ham will be submitted. This study compares two methods to predict the SFT in slaughter line: an automatic system using an SVM model (Support Vector Machine) and a manual measurement of the fat carried out by an experienced operator, in terms of accuracy and economic benefit. These two methods were compared to the golden standard obtained by measuring SFT with a ruler in a sample of 400 hams equally distributed within each SFT class. The results show that the SFT prediction made by the SVM model achieves an accuracy of 75.3%, which represents an improvement of 5.5% compared to the manual measurement. Regarding economic benefits, SVM model can increase them between 12 and 17%. It can be concluded that the classification using SVM is more accurate than the one performed manually with an increase of the economic benefit for sorting.

Effects of dietary CP and amino acid restriction on the growth dynamics of organs and body components in entire male, castrated and female pigs

The optimized use of dietary nutrients and the accurate knowledge of the growth dynamics of body components is important for efficient pig production. This study aimed at evaluating the growth of carcass components and organs of Swiss Large White pigs from birth to 140 kg BW depending on the CP and amino acid (AA) supply. A total of 66 entire males (EM), 58 castrates (CA) and 66 female (FE) pigs were used. From 20 kg BW onwards, they had either ad libitum access to a control (C) or a diet (LP) with 20% lower CP, lysine, methionine + cystine, threonine and tryptophan content compared to C. The weight of organs, primal cuts and external fat were recorded in eight EM and eight FE; at 10 kg BW, on two EM, CA and FE each, and at 20 kg BW, on eight pigs from each sex. From 40 to 140 kg BW at 20 kg intervals, measurements were recorded on four pigs per sex and dietary treatment. The weight of each component was related to empty body (EB) using allometric regressions. Kidneys were heavier (P<0.05) in C- than LP-pigs and in EM than CA and FE. Above 21 kg EB weight, growth rate of LP-FE overpassed (P<0.05) the one of C-pigs. Consequently, LP-FE had heavier (P<0.05) lean cuts than C-pigs in the finisher period. However, LP-CA and LP-EM displayed lower (P<0.05) weights and growth rates of the lean cuts than C-CA and C-EM. Shoulder and loin weights and growth rates were reduced (P<0.05) in LP-pigs when compared to C-pigs. Growth rates of the ham were greater (P<0.05) in LP-FE than C-FE, whereas in LP-EM and LP-CA they were lower (P<0.05) than their C-counterparts. Total amounts of subcutaneous fat, backfat, ham fat and shoulder fat were lower (P<0.05) in C- than LP-pigs. The total amount of subcutaneous fat, backfat and shoulder fat of C-CA was, regardless of diet, greater (P<0.05) than of C-FE. In the LP group, this difference was even more pronounced. The amount of deposited ham fat was greater (P<0.05) in LP-CA than LP-FE, but not in C-CA v. C-FE. Differences in kidney weights suggested a greater nitrogen clearance required in C-pigs. Overall, dietary restriction and sex did not affect all body parts to the same extent. This study further suggests the possibility to reduce the CP and AA supply in FE without compromising the yield of primal lean cuts or increasing the amount of subcutaneous fat.

Growth, carcass characteristics and meat quality of Chinese indigenous Yanan pig crossbred with Duroc and Berkshire genotypes

The objective of the present study was to evaluate the effects of crossbreeding on the growth, carcass characteristics and meat quality of Chinese native Yanan (YN) pig breed and related crossbreeds, including Duroc × Yanan (DY) and Duroc × (Berkshire × Yanan) (DBY). In total, 60 pigs (20 per breed) were used in the study. The results showed that both crossbreeds, especially DBY pigs, exhibited improved growth and carcass characteristics compared with those of purebred YN pigs. Moreover, the two crossbreeds, especially DBY pigs, produced acceptable meat-quality characteristics (normal pH and meat-colour values, high intramuscular fat content and water-holding capacity, acceptable muscle-fibre parameters, and strong pork flavour) similar to those of YN pigs. M. longissimus lumborum contained eight essential amino acids, with high contents in all pigs. C18:1, C16:0, C18:0, and C18:2 were the main fatty acids in M. longissimus lumborum in the three breeds, and a polyunsaturated:saturated fatty acid ratio of ~0.2 was observed in DBY and YN pigs. These results indicated that DBY pigs exhibit an acceptable total production performance and could be extensively used in commercial pig production to provide high-quality niche products.

On-line Ham Grading using pattern recognition models based on available data in commercial pig slaughterhouses

The thickness of the subcutaneous fat in hams is one of the most important factors for the dry-curing process and largely determines its final quality. This parameter is usually measured in slaughterhouses by a manual metrical measure to classify hams. The aim of the present study was to propose an automatic classification method based on data obtained from a carcass automatic classification equipment (AutoFom) and intrinsic data of the pigs (sex, breed, and weight) to simulate the manual classification system. The evaluated classification algorithms were decision tree, support vector machines (SVM), k-nearest neighbour and discriminant analysis. A total of 4000 hams selected by breed and sex were classified as thin (0-10 mm), standard (11-15 mm), semi-fat (16-20 mm) and fat (>20 mm). The most reliable model, with a percentage of success of 73%, was SVM with Gaussian kernel, including all data available. These results suggest that the proposed classification method can be a useful online tool in slaughterhouses to classify hams.

The influence of housing and feeding systems on selected fattening and slaughter parameters of finishing pigs with different genotypes

The aim of the present study was to demonstrate the influence of housing and feeding systems on selected fattening and slaughter parameters of finishers with different genotypes. The experimental population consisted of 1200 finishers in three genetic variants from the Landrace (L), Large White (LW), Duroc (D) and Pietrain (P) breeds: 400 finishers L × [D × P] genotype, 400 finishers LW × [D × P] genotype and 400 finishers [L × LW] × [D × P] genotype. Subgroups were isolated for each genetic variant with the experimental factors: housing system (slatted floor or deep litter) and feeding system (dry or liquid). Selected fattening parameters were analysed: final liveweight (kg), mortality (%), average daily gain (g/day) and feed conversion ratio (kg/kg gain). Additionally, slaughter parameters were analysed: carcass weight (kg), height of longissimus dorsi (LD) muscle (mm), backfat thickness (mm) and lean meat content (%). The housing system strongly affected the final liveweight, average daily gain and carcass weight. To a lesser degree, this factor determined the mortality, feed conversion ratio, height of LD muscle, backfat thickness and lean meat content. The feeding system substantially affected almost all fattening parameters, except for the mortality. Statistical analysis of slaughter parameters showed that the impact of the feeding system was confirmed statistically only in terms of carcass weight. Genotype largely determined the final liveweight, average daily gain, carcass weight and lean meat content. Taking into account interactions of all factors, the most favourable effect in terms of production was to fattening four-way crossbreeds [L × LW] × [D × P] on slatted floors and fed by liquid feeding.

Effects of pork differentiation strategies in Canada on pig performance and carcass characteristics

Performance and quality traits were measured in carcasses from combinations of genotype, diet supplement, slaughter weight, and carcass chilling regime. Iberian-crossed pigs had lower live animal performance than Duroc and Lacombe. From 70 to 115 kg, Lacombe pigs grew slightly faster than Duroc. Duroc carcasses had a higher lean percentage, heavier ham and picnic primals, and lighter loins and bellies, compared with Lacombe and Iberian. Heavier carcasses had lower lean yield, except those from Iberian-crossed pigs, and bigger bellies. Meat from Duroc-crossed pigs was lighter in colour and higher in marbling, with intermediate values for fat hardness. Iberian carcasses displayed dark meat with intermediate marbling and the hardest fat. Meat from Lacombe pigs was the leanest although, like in all three breeds, marbling scores were higher in heavier carcasses. Generally, supplementing with canola and flax decreased and blast chilling increased fat hardness values. Dietary canola also seemed to affect meat colour traits, but these effects were not consistent among breeds and slaughter weights. The commercial combination of Duroc breed, control diet, and 115-kg slaughter weight showed a balance in terms of performance, carcass, and quality traits. Other combinations evaluated in this study showed potential to efficiently produce differentiated pork.

Factors affecting the daily feed intake and feed conversion ratio of pigs in grow-finishing units: the case of a company

BACKGROUND

The aim of this study was to use mathematical modeling to identify and quantify the main factors that affect daily feed intake (DFI) and feed conversion ratio (FCR) in grow-finishing (GF) pig units. We evaluated the production records of 93 GF farms between 2010 and 2013, linked to a company, working in a cooperative system, located in western Paraná State, Brazil. A total of 683 batches, consisting of approximately 495,000 animals, were used. Forty production factors related to the management, health, plant and equipment, nutrition, genetics and environment were considered. The number of pigs per pen, type of feeder, origin and sex (the last two variables were combined in the models) of the animals and initial and final body weights were included in the final models to predict DFI and FCR (dependent variables). Additionally, the duration of the GF phase was included for the parameter FCR. All factors included in the final models had significant effects for both dependent variables.

RESULTS

There was a reduction in DFI (0.04 kg) (P < 0.001) and an improvement in FCR (6.0 points) (P < 0.001) in batches from pens with less than 20 animals compared with batches from pens with more than 20 animals. In barns with "other" feeder types (mostly the linear dump type) different of conical semiautomatic feeder, a reduction of DFI (0.03 kg) (P < 0.05) and improved FCR (3.0 points) (P < 0.05) were observed. Batches of barrows from units specialized for producing piglets (SPU) had higher DFI (approximately 0.02 kg) (P < 0.01) than batches of females and batches of mixed animals from SPU, and batches of mixed animals from farms not specialized for piglet production (farrow-to-finish farms). Batches of females from SPU and mixed batches from SPU had better FCR (5.0 and 3.0 points respectively) (P < 0.001 and P < 0.001, respectively) than batches of piglets originating from farrow-to-finish farms. The variables selected for the final models explained approximately 50 and 64 % of the total variance in DFI and FCR, respectively.

CONCLUSIONS

The models are tools for the interpretation of the factors related to the evaluated parameters, aiding in the identification of critical aspects of production. The main parameters affecting DFI and FCR in this company during the GF period were the number of pigs per pen, the type of feeder used and the combination origin-sex of the animals.

Prevalence of boar taint in commercial pigs from Spanish farms

The presence of boar taint can affect the sensory quality of pork because the "off" odours and flavours can be detected by consumers. The aim of this study was to determine the prevalence of boar taint in pig carcasses from 30 Spanish farms located in different regions of the country. Hot carcass weight and subcutaneous fat thickness means were 79.4±8.19 kg and 18.4±5.09 mm, respectively. Subcutaneous fat samples were classified into different levels according to androstenone and skatole concentrations in adipose tissue measured using GC-MS and HPLC. Androstenone results were: 87.4% of the carcasses below 0.50 μg/g, 7.1% from 0.50 to 1.00 μg/g (medium level), and 5.5% ≥1.00 μg/g (high level). Skatole results were: 88.9% of the carcasses below 0.10 μg/g, 4.5% from 0.10 to 0.20 μg/g (medium level), and 6.6% ≥0.20 μg/g (high level). Given these results, a future online method to classify carcasses according to boar taint is strongly recommended.

Managing variability in decision making in swine growing-finishing units

Background

Analysis of data collected from pig farms may be useful to understand factors affecting pig health and productive performance. However, obtaining these data and drawing conclusions from them can be done at different levels and presents several challenges. In the present study, information from 688 batches of growing-finishing (GF) pigs (average initial and final body weight of 19.1 and 108.5 kg respectively) from 404 GF farms integrated in 7 companies was obtained between July 2008 and July 2010 in Spain by survey. Management and facility factors associated with feed conversion ratio (FCR) and mortality were studied by multiple linear regression analysis in each single company (A to G) and in an overall database (OD). Factors studied were geographic location of the farm, trimester the pigs entered the farm, breed of sire and sex segregation in pens (BREGENSEG), use of circovirus vaccine, number of origins the pigs were obtained from, age of the farm, percentage of slatted floor, type of feeder, drinker and ventilation, number of phases and form of feed, antibiotic administration system, water source, and number and initial weight of pigs.

Results

In two or more companies studied and/or in OD, the trimester when pigs were placed in the farm, BREGENSEG, number of origins of the pigs, age of the farm and initial body weight were factors associated with FCR. Regarding mortality, trimester of placement, number of origins of the pigs, water source in the farm, number of pigs placed and the initial body weight were relevant factors. Age of the farm, antibiotic administration system, and water source were only provided by some of the studied companies and were not included in the OD model, however, when analyzed in particular companies these three variables had an important effect and may be variables of interest in companies that do not record them.

Conclusions

Analysing data collected from farms at different levels helps better understand factors associated with productive performance of pig herds. Out of the studied factors trimester of placement and number of origins of the pigs were the most relevant factors associated with FCR and mortality.

A co-association network analysis of the genetic determination of pig conformation, growth and fatness

BACKGROUND

Several QTLs have been identified for major economically relevant traits in livestock, such as growth and meat quality, revealing the complex genetic architecture of these traits. The use of network approaches considering the interactions of multiple molecules and traits provides useful insights into the molecular underpinnings of complex traits. Here, a network based methodology, named Association Weight Matrix, was applied to study gene interactions and pathways affecting pig conformation, growth and fatness traits.

RESULTS

The co-association network analysis underpinned three transcription factors, PPARγ, ELF1, and PRDM16 involved in mesoderm tissue differentiation. Fifty-four genes in the network belonged to growth-related ontologies and 46 of them were common with a similar study for growth in cattle supporting our results. The functional analysis uncovered the lipid metabolism and the corticotrophin and gonadotrophin release hormone pathways among the most important pathways influencing these traits. Our results suggest that the genes and pathways here identified are important determining either the total body weight of the animal and the fat content. For instance, a switch in the mesoderm tissue differentiation may determinate the age-related preferred pathways being in the puberty stage those related with the miogenic and osteogenic lineages; on the contrary, in the maturity stage cells may be more prone to the adipocyte fate. Hence, our results demonstrate that an integrative genomic co-association analysis is a powerful approach for identifying new connections and interactions among genes.

CONCLUSIONS

This work provides insights about pathways and key regulators which may be important determining the animal growth, conformation and body proportions and fatness traits. Molecular information concerning genes and pathways here described may be crucial for the improvement of genetic breeding programs applied to pork meat production.

Effects of ractopamine administration and castration method on muscle fiber characteristics and sensory quality of the longissimus muscle in two Piétrain pig genotypes

Single and combined effects of ractopamine supplementation (RAC, 7.5 vs. 0 ppm), castration method (surgical castration: SC vs. immuno-castration: IM) and genotype (genotype A: GA vs. GB containing 25% or 50% Piétrain) were determined on longissimus muscle (LM) fiber traits and quality of pork (n=512). RAC increased fiber IIX cross-sectional area (P=0.009) and decreased glycolytic potential (P=0.02) and pork tenderness (P<0.001). Fiber traits indicated that LM of IM pigs was more oxidative (P<0.05) and meat had slightly higher (P=0.04) off-flavor score and WBSF than SC. LM from GB pigs was paler (P<0.05) and had greater (P<0.05) glycolytic potential, IIX fiber cross sectional area and pork off-flavor than GA. RAC supplementation, castration method and genotype or their combination affected some fiber traits and some quality parameters but differences reported were small indicating these treatments or their combination could be used without major prejudice to meat quality.

Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues

Human studies of the influence of aging and other factors on intermuscular fat (INTMF) were reviewed. Intermuscular fat increased with weight loss, weight gain, or with no weight change with age in humans. An increase in INTMF represents a similar threat to type 2 diabetes and insulin resistance as does visceral adipose tissue (VAT). Studies of INTMF in animals covered topics such as quantitative deposition and genetic relationships with other fat depots. The relationship between leanness and higher proportions of INTMF fat in pigs was not observed in human studies and was not corroborated by other pig studies. In humans, changes in muscle mass, strength and quality are associated with INTMF accretion with aging. Gene expression profiling and intrinsic methylation differences in pigs demonstrated that INTMF and VAT are primarily associated with inflammatory and immune processes. It seems that in the pig and humans, INTMF and VAT share a similar pattern of distribution and a similar association of components dictating insulin sensitivity. Studies on intramuscular (IM) adipocyte development in meat animals were reviewed. Gene expression analysis and genetic analysis have identified candidate genes involved in IM adipocyte development. Intramuscular (IM) adipocyte development in human muscle is only seen during aging and some pathological circumstance. Several genetic links between human and meat animal adipogenesis have been identified. In pigs, the Lipin1 and Lipin 2 gene have strong genetic effects on IM accumulation. Lipin1 deficiency results in immature adipocyte development in human lipodystrophy. In humans, overexpression of Perilipin 2 (PLIN2) facilitates intramyocellular lipid accretion whereas in pigs PLIN2 gene expression is associated with IM deposition. Lipins and perilipins may influence intramuscular lipid regardless of species.

Carcass quality, physico-chemical parameters, muscle fibre traits and myosin heavy chain composition of m. longissimus lumborum from Puławska and Polish Large White pigs

In 54 Puławska pigs and 60 Polish Large White pigs (PLW), slaughtered at 30 and 100 kg body weight, carcass and meat quality of m. longissimus lumborum were studied. Analysis revealed that in both examined body weight groups, hot carcass weight, carcass yield percentage, meat content, and weight of ham and carcass ham percentage were significantly lower and backfat thickness higher for Puławska pigs compared to PLW pigs, while PLW pigs exhibited significantly longer carcasses, greater loin eye area, and, in the case of lighter pigs, smaller proportion of loin in the carcass. Muscles of Puławska pigs, in the lighter group, had higher IMF content and a* value, while in the heavier group they exhibited higher pH(45), pH(24) and a* values, lower L*, drip loss, WHC, and thermal loss compared with PLW pigs. PLW pigs had higher WB and hardness values and more glycolytic muscles characterised by higher TNF.

Effects of ractopamine administration and castration method on the response to preslaughter stress and carcass and meat quality in pigs of two Piétrain genotypes

The objective of this study was to evaluate the effects of ractopamine supplementation, castration method, and their interaction on the behavioral and physiological response to preslaughter stress and carcass and meat quality of 2 Piétrain genotypes. A total of 1,488 male pigs (115 ± 5 kg BW) were distributed according to a 2 × 2 × 2 factorial arrangement of treatments. The first factor was ractopamine supplementation with 2 groups of pigs (376 and 380 pigs each) receiving 7.5 mg/kg of ractopamine (RAC) or not (NRAC) in their diet during the last 28 d of the finishing period. The second factor was castration method, with 744 surgical castrates (SC) and 744 immunized males (IM), and the third factor was the genotype with 2 crossbreeds containing 50% (genotype A, GA; n = 744) or 25% (genotype B, GB; n = 744) Piétrain genetics. Surgical castration took place at 2 d of age, whereas immunization against gonadotropin-releasing factor (GnRF) was performed through 2 subcutaneous injections of GnRF analog (Improvest, 2 mL) at 10 and 4 wk before slaughter. At loading more vocal stimulation was needed by the handler to drive GB pigs forward through the farm alley (P = 0.01) and RAC-fed GB pigs through the ramp (P = 0.02). Feeding RAC to IM increased the number of fights in lairage compared with SC (P = 0.03). Feeding RAC shortened fighting bouts compared with NRAC pigs (P = 0.05). The SC-GA pigs showed a greater gastrointestinal tract temperature during unloading (P = 0.05) and lairage time (P = 0.03). Blood creatine kinase (CK) concentrations were greater (P = 0.04) in SC compared with IM, and no difference was found in the concentrations of stress hormones in urine collected postmortem. Dressing yield was greater (P = 0.01) in RAC and SC-GB pigs. Carcasses from RAC pigs and IM were leaner than those from NRAC and SC pigs (P < 0.001 and P = 0.002, respectively). Feeding RAC to IM increased drip loss in the LM (P = 0.05). Warner-Bratzler shear force values were slightly greater in the LM from RAC-GB pigs and from IM compared with SC (P = 0.01 and P < 0.001, respectively) and in the semimembranosus muscle of RAC pigs (P = 0.006). In conclusion, immunization against GnRF more than the use of Piétrain genotypes appears to be a viable alternative to the use of ractopamine, as it seems to promote production of lean carcasses without compromising animal welfare and pork quality.

Effects of trailer design on animal welfare parameters and carcass and meat quality of three Pietrain crosses being transported over a long distance

This study aimed at evaluating the effects of trailer design on stress responses and meat quality traits of 3 different pig crosses: 50% Pietrain breeding with halothane (HAL)(Nn) (50Nn); 50% Pietrain breeding with HAL(NN) (50NN); and 25% Pietrain breeding with HAL(NN) genotype (25NN). Over a 6-wk period, pigs (120 pigs/crossbreed) were transported for 7 h in either a pot-belly (PB) or flat-deck (FD) trailer (10 pigs/crossbreed(-1)·trailer(-1)·wk(-1)). Temperature (T) and relative humidity (RH) were monitored in each trailer. Behaviors during loading and unloading, time to load and unload, and latency to rest in lairage were recorded, whereas a sub-population of pigs (4 pigs/crossbreed(-1)·trailer(-1)·wk(-1)) was equipped with gastro-intestinal tract (GIT) temperature monitors. Blood samples were collected at exsanguination for measurement of cortisol, creatine kinase (CK), lactate, haptoglobin, and Pig-MAP concentrations. Meat quality data were collected at 24 h postmortem from the LM and semimembranosus (SM) and adductor (AD) muscles of all 360 pigs. Greater T were recorded in the PB trailer during transportation (P = 0.006) and unloading (P < 0.001). Delta GIT temperature was greater (P = 0.01) in pigs unloaded from the PB. At loading, pigs tended to move backwards more (P = 0.06) when loaded on the FD than the PB trailer. At unloading, an interaction was found between trailer type and crossbreed type, with a greater (P < 0.01) frequency of overlaps in 50NN and 25NN pigs and slips/falls in 50Nn and 50NN pigs from the FD than the PB trailer. Cortisol concentrations at slaughter were greater (P = 0.02) in pigs transported in the PB than FD trailer. Greater lactate concentrations were found in 50Nn and 50NN pigs (P = 0.003) and greater CK concentrations (P < 0.001) in 50Nn pigs. As expected, 50Nn pigs produced leaner (P < 0.001) carcasses, with greater (P = 0.01) dressing percentages, as well as lower (P < 0.001) ultimate pH values and greater (P < 0.001) drip loss percentages in the LM and greater (P = 0.002) drip losses and a paler color (greater L* values, P = 0.02) in the SM than 50NN pigs. When used for long distance transportation under controlled conditions, the PB trailer produced no detrimental effects on animal welfare or pork quality. Pigs with 50% Pietrain crossbreeding appear to be more responsive to transport stress, having the potential to produce acceptable carcass and pork quality, provided pigs are free of the HAL gene.

Carcass and meat quality traits of four commercial pig crossbreeds in China

We evaluated carcass and meat quality traits of two Chinese native crossbreeds Landrace x Meishan (LM) and Duroc x (Landrace x Meishan) (DLM) and two foreign crossbreeds Duroc x (Landrace x Yorkshire) (DLY) and PIC (an imported five-way crossbreed). One hundred and twenty weaned pigs (half castrated males and half females) were reared and slaughtered at a predestinated slaughter age. The general carcass and meat quality traits were measured and analyzed. The DLY and PIC crosses had significantly heavier live weights (93.39 and 96.33 kg, P < 0.01), significantly higher dressing percentages (80.65 and 79.39%, P < 0.05), significantly bigger loin areas (42.69 and 43.91 cm(2), P < 0.001), and significantly more lean carcasses (65.78 and 66.40%, P < 0.001) than LM and DLM. On the other hand, LM had a significantly lower live weight (70.29 kg, P < 0.01), significantly thicker back fat (3.54 cm, P < 0.001), significantly less lean carcasses (46.82%, P < 0.001), and significantly less ham and breech (26.53%, P < 0.05) than the other crossbreeds. Among meat quality parameters, LM had the highest intramuscular fat content (5.02%, P < 0.001) and the smallest fiber area (3126.45 μm(2), P < 0.01). However, PIC showed the lowest pH(1) (5.82, P < 0.01) and pH(2) (5.63, P < 0.01), the highest drip loss (2.89%, P < 0.01), and the lowest intramuscular fat (1.35%, P < 0.001). We concluded that LM and DLM had good meat quality traits but poorer carcass traits than DLY and PIC; DLY had good carcass and meat quality traits; PIC had good carcass traits, but it had less intramuscular fat, lower pH and higher drip loss.

Effects of genotype and dietary oil supplementation on performance, carcass traits, pork quality and fatty acid composition of backfat and intramuscular fat

A 42-day study was conducted to evaluate the effect of genotype: terminal sire line Duroc×F1 (DC×F1); terminal sire line Embrapa MS-115×F1 (MS-115×F1); and MS-115×Moura (MS-115×MO) and three dietary oil sources: soybean; canola; and canola+flax, on performance, carcass traits, pork quality, and fatty acid composition. Genotype affected the technological quality of pork and fatty acid profile. MS-115-sired pigs had better meat color and Duroc-sired pigs had higher intramuscular fat content, more saturated fat and better omega-6/omega-3 ratio. Moura breed influenced positively meat tenderness and intramuscular fat. Diet did not affect the technological quality of the meat. Canola or canola+flax oil diet supplementations increased monounsaturated and C18:3 and decreased C18:2 fatty acids, reducing the omega-6/omega-3 ratio. The best omega-6/omega-3 ratio was obtained through supplementation with canola+flax.

Functional analysis of muscle gene expression profiles associated with tenderness and intramuscular fat content in pork

Warner-Bratzler shear force (WBSF) and % intramuscular fat content (IMF) are objective meat quality measurements that are significantly correlated with aspects of palatability such as tenderness, flavour and juiciness. Using cDNA microarrays, Musculus longissimus transcriptomic profiles at slaughter were compared in samples displaying lower or higher IMF (n=8) and WBSF values on day 1 post mortem (n=8). 101 identified genes were differentially expressed in relation to WBSF, while 160 genes were associated with differences in IMF. Reduced expression of protein synthesis genes and enhanced expression of genes involved in protein degradation were associated with lower WBSF values on day 1. Pathways including oxidative phosphorylation and the citrate cycle were significantly associated with higher IMF. Many lipid oxidation and fatty acid metabolism pathway genes were down-regulated in high IMF tissue, suggesting a suppression of fatty acid turnover in muscle with higher fat content. Identified genes provide targets for the discovery of novel genetic variation influential on pork palatability.

Variation in the IGF2 gene promoter region is associated with intramuscular fat content in porcine skeletal muscle

Intramuscular fat (IMF) and subcutaneous fat (back fat-BF) are two of the major fat depots in livestock. A QTN located in the insulin-like growth factor 2 gene (IGF2) has been associated with a desirable reduction in BF depth in pigs. Given that the lipid metabolism of intramuscular adipocytes differs from that of subcutaneous fat adipocytes, this study aimed to search for genetic variation in the IGF2 gene that may be associated with IMF, as well as BF, in diverse pig breeds. Four proximal promoter regions of the IGF2 gene were characterised and the association of IGF2 genetic variation with IMF and BF was assessed. Six promoter SNPs were identified in four promoter regions (P1-P4; sequence coverage 945, 866, 784 and 864 bp, respectively) in phenotypically diverse F1 cross populations. Three promoter SNPs were subsequently genotyped in three pure breeds (Pietrain = 98, Duroc = 99 and Large White = 98). All three SNPs were >95% monomorphic in the Pietrain and Duroc breeds but minor alleles were at moderate frequencies in the Large White breed. These SNPs were linked and one was located in a putative transcription factor binding site. Five haplotypes were inferred and three combined diplotypes tested for association with IMF and BF in the Large White. As expected haplotype 1 (likely in LD with the beneficial QTN allele) was superior for BF level. In contrast, the heterozygote diplotype of the most common haplotypes (1 and 2) was associated with higher IMF and marbling scores compared to either homozygote. Gene expression analysis of divergent animals showed that IGF2 was 1.89 fold up-regulated in muscle with higher compared to lower IMF content. These findings suggest that genetic variation in the promoter region of the IGF2 gene is associated with IMF content in porcine skeletal muscle and that greater expression of the IGF2 gene is associated with higher IMF content.

Effect of an elevated monounsaturated fat diet on pork carcass and meat quality traits and tissue fatty acid composition from York-crossed barrows and gilts

Fifty-seven York-crossed barrows and gilts were fed either a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic acid (HO with 43% C18:1, Greedy-Grass OLIVA®). There were no interactions between dietary treatment and gender and there were no differences in intramuscular and subcutaneous fatty acid composition between sexes (P>0.05). Similar primal cut yields, composition of major primal cuts, and carcass and meat quality characteristics were found for HO and CONTROL fed pigs. Apart from a few significant but small differences for some fatty acids, intramuscular fatty acid composition was similar for both dietary treatments. Subcutaneous fat from HO fed pigs had a 6.9% increase in total monounsaturated fatty acids and a 9.3% reduction in total polyunsaturated fatty acids (P<0.05) compared with CONTROL fed animals, without adversely affecting carcass quality and producing suitable hams for processing by the meat industry.

A review of the factors influencing the development of intermuscular adipose tissue in the growing pig

Compared with subcutaneous or abdominal fat depots of pig carcasses, intermuscular fat displays a number of original properties. It cannot be easily removed from fresh or processed meat delivered to consumers and has therefore an influence on consumer acceptability of pork. Particular compositional characteristics of intermuscular fat include low lipid content and small size of adipocytes. How age (or body weight), gender, castration, environmental temperature, feeding restriction, diet composition, as well as genetic factors affect intermuscular fat development and composition are surveyed in this review paper. Up to now, few studies have specifically dealt with the intermuscular compartment of body fat while very abundant information is available on the subcutaneous one. As a general rule, any factor, either genetic or non-genetic, which causes a decrease of whole carcass fat deposition generates a higher relative importance of the intermuscular fraction of total fat as well as an increased degree of unsaturation of constituent fatty acids.

Relationships between biochemical characteristics and meat quality of Longissimus thoracis and Semimembranosus muscles in five porcine lines

Five porcine genetic lines which represent a high proportion of European pig production were fully characterized for meat quality parameters and muscle biochemical characteristics (Longissimus thoracis, LT, and Semimembranosus, SM). The line characterisation was based on 100 animals each representing Large White, Landrace, Duroc, Piétrain (Halothane negative) and Meishan (a Meishan/Large White crossbred line) prevalent genetic backgrounds. Different meat quality parameters (pH 45min, pH ultimate, electrical conductivity, and colour measurements), as well as muscle water holding capacity, muscle metabolic and contractile traits, fibre type, size and frequencies were measured and their relationships studied. The main differences in the LT were found between the Meishan and Piétrain genetic lines, in relation to the muscle fibre size (larger in Piétrain). The Duroc line was characterized by the muscle oxidative traits and the Landrace by the high percentage of fast glycolytic fibres. In SM, Duroc and Piétrain were distinguished from Landrace and Meishan according to the metabolic and contractile characteristics of this muscle. Large White tended to lie between the other breeds for many of the traits. The measured muscle characteristics were related to differences in drip loss and marbling values and could thereby influence the eating quality of pork. Overall the results show differences between the genetic lines for a number of muscle traits which could have impact on consumer appeal and eating quality. The present findings should serve to emphasise the importance of including eating quality as a trait in breed selection.