Back-fat thickness as a primary index reflecting the yield and overall acceptance of pork meat

A genome-wide association study identified candidate regions and genes for commercial traits in a Landrace population

Backfat thickness (BFT) and feed conversion ratio (FCR) are important commercial traits in the pig industry. With the increasing demand for human health and meat production, identifying functional genomic regions and genes associated with these commercial traits is critical for enhancing production efficiency. In this research, we conducted a genome-wide association study (GWAS) on a Landrace population comprising 4,295 individuals with chip data for BFT and FCR. Our analysis revealed a total of 118 genome-wide significant signals located on chromosomes SSC1, SSC2, SSC7, SSC12, and SSC13, respectively. Furthermore, we identified 10 potential regions associated with the two traits and annotated the genes within these regions. In addition, enrichment analysis was also performed. Notably, candidate genes such as SHANK2, KCNQ1, and ABL1 were found to be associated with BFT, whereas NAP1L4, LSP1, and PPFIA1 genes were related to the FCR. Our findings provide valuable insights into the genetic architecture of these two traits and offer guidance for future pig breeding efforts.

Meat yield and quality characteristics of Woori heukdon pigs as affected by dietary amino acids and chromium supplementation

This study aimed to assess the effect of combined dietary supplementation with amino acids and chromium on carcass traits, meat yield and quality properties of finishing Woori heukdon (WHD) pigs. For this purpose, forty same-age WHD piglets were equally assigned into control and experimental groups (n = 20 per group). The control group were received a basal diet while, the experimental group were received a basal diet supplemented with additional 4% lysine, isoleucine, methionine, threonine, valine and tryptophan during growing phase (30-65 kg body weight), and a basal diet supplemented with 0.1% (w/w) chromium picolinate during finishing period. The pigs were fed ad libitum with the diets until they reached a common market weight of around 110 kg. The animals were slaughtered and assessed for carcass traits and composition, and meat quality of loin, ham and belly cuts. Results showed that no differences in the live weight, carcass weight and total meat yield occurred between control and experimental groups (p-> 0.05). The dietary supplementations significantly increased the intramuscular fat content of the loin and ham cuts, and decreased the fat content of belly cut (p < 0.05). No differences in the meat quality (e.g., pH and color) occurred between the control and experimental diets (p > 0.05). Noticeably, the dietary supplementation reduced the concentration of polyunsaturated fatty acids (PUFA)-derived unpleasant aldehydes, and increased the number and quantity of Maillard reaction-derived pleasant aroma volatiles. It is suggested that dietary supplementation with the amino acids and chromium could be used to improve the meat quality property of WHD pigs.

Replacing yellow maize with Illipe nut (Shorea stenoptera) improves growth performance and meat quality of porker pigs

The effects of incorporating Illipe nut into the diet of pigs, in replacement of yellow maize, on their growth performance and meat quality was investigated in a 60 days feeding trial. Twenty-four male pigs were divided into two treatments and fed diets with 0% (T1) or 15% (T2) Illipe nut inclusion. Feed intake, live weight (LW) and backfat thickness (BFT) were taken and used to calculate average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR) and increase in backfat (IBF). At the end of the trial, final LW and BFT were measured. Pigs were then slaughtered and hot carcass weight (HCW), pH45mins, pH24hrs and dressing percentage (DP) were determined. Other analysis, including total moisture, thawing loss (TL), cooking loss (CL) and water holding capacity (WHC), were conducted on pork samples. Nutritional content and fatty acid (FA) composition of pork samples were analyzed, and nutritional indices were calculated. Improvements (P < 0.05) in final LW, ADG, final BFT, IBF and FCR were seen in pigs fed the T2 diet. Additionally, the T2 pork was superior (P < 0.05) in HCW, DP, pH24hrs, TL, CL, total moisture and WHC than T1 pork. The FA composition of T2 pork was also improved, with a higher (P < 0.05) PUFA:SFA ratio, indicating lower SFA and higher PUFA levels than T1 pork. Along with this, T2 pork had lower (P < 0.05) index of atheroginicity (IA) and higher (health promoting index) HPI levels, indicating that the T2 pork is a healthier choice for consumption. These findings indicate that the inclusion of 15% Illipe nut into the diet of porker pigs improved their overall growth performance and meat quality.

Integrated transcriptomic and metabolomic analyses reveal heterosis for meat quality of Neijiang pigs

Obese pig breeds have excellent meat quality, while lean pig breeds have high lean meat percentage and feed conversion rate. However, due to their respective shortcomings, obese pig and lean pig breeds are unable to balance production and consumption needs. Therefore, this study crossbred the obese Chinese pig breed Neijiang (NJ) with lean type Large White pigs (LW) to produce Neijiang × Large White(NL) pigs. This study compared the differences in carcass and meat quality traits between NJ pigs and NL pigs, and for the first time comprehensively analyzed the longissimus dorsi muscle of NJ pigs and NL pigs using transcriptomics and metabolomics. The results of slaughter and meat quality testing indicate that the carcass performance of NL pigs was significantly higher than that of NJ pigs, and the excellent meat quality characteristics of NJ pigs were also retained on NL pigs. The results of transcriptomics and metabolomics showed that there were 635 differentially expressed genes (DEGs) and 11 significantly different metabolites (SDM) in the longissimus dorsi muscle of NJ and NL pigs. The results of multi omics joint analysis showed that betaine, uridine triphosphate, glycerol 3-phosphate, and glutathione in SDMs were enriched in the shared KEGG pathway and significantly correlated with C1QTNF12, GGA3, SLC16A6, and RXRG in DEGs. In general, it is feasible to enhance the production performance of NJ pigs through crossbreeding with LW pigs. The hybrid offspring inherit the advantages of these two varieties, maintaining excellent meat quality while also having better carcass performance.

The association of P2 and lean % estimates from commercial measurement systems with computed tomography determined composition within Australian pork abattoirs

Pork carcasses were obtained from three abattoirs in Australia (n = 345) where technologies enabled collection of post slaughter measures of P2 fat depth (mm) (Hennessy Grading Probe (HGP), AutoFom III, PorkScan Lite) and estimates of carcass lean % (HGP, AutoFom III, PorkScan Plus). Computed tomography (CT) was used to scan carcasses and determine lean and fat %, with the strength of associations with abattoir measurement devices determined. The AutoFom III lean % demonstrated the strongest associations with whole carcass CT lean % (R2 0.63, RMSE 1.73) and fat % (R2 0.68, RMSE 1.80) and with section (fore, loin, belly and hind) CT composition. The association of P2 from AutoFom III was lower in comparison, however remained superior to other commercial devices (PorkScan Lite and HGP). Porkscan Plus lean % demonstrated moderate associations with whole carcass and section CT lean and fat %, with R2 values generally less than half those of the AutoFom III. The HGP demonstrated weakest associations with CT lean and fat % using either lean % or P2 outputs, which is likely related to data being collected from only the P2 measurement site. This is the first experiment to compare the strength of associations between multiple pork abattoir measurement devices and CT lean and fat % in Australia. P2 is the current industry standard for the assessment of lean yield in pork, however demonstrates weaker associations with carcass CT composition than devices capable of capturing multiple measures across the carcass like AutoFom III and PorkScan Plus.

Relationship between the pH of semispinalis capitis muscle and the quality properties of pork shoulder butt and belly slices

This study investigated the relationship of carcass characteristics such as hot carcass weight and back fat thickness (BFT) and the pH of semispinalis capitis (SC) with the cooking loss (CL) of pork shoulder butt and the CL and Warner-Bratzler shear force (WBSF) of belly. BFT was correlated with the CLs of the butt slices (r s  = -0.30) and the belly slices (r s  = -0.27 to -0.32). The pH of the SC muscle showed a correlation with the CLs of the butt slices (r s  = -0.45) and the belly slices of the 6th and 11th thoracic vertebrae (r s  = -0.28 to -0.33). Additionally, the correlations (r s  = 0.62 to 0.77) were observed in the CLs among the belly slices. However, the WBSF of the belly slices did not show correlations with others. Therefore, the pH of the SC muscle as well as BFT can be used to obtain information on the CL of shoulder butts and bellies in carcasses.

Rearing hogs on pasture minimally impacts pork composition

Managing swine on pasture is increasing in popularity for both the consumer and producer. This interest appears to be driven by an effort to create an improved perception of environmentally sustainable practices and increased animal welfare, while keeping start-up costs low. However, evidence-based guidance on pasture management practices that support quality pork production and environmentally sustainable procedures is lacking. The objective of this work was to quantify the impact of pasture rearing on pig growth efficiency and pork quality. In this pilot study, 20 pigs similar in genetics, age, weight, and sex ratio were divided across indoor (n = 10) and Outdoor (n = 10) housing environments. Pigs were weighed every 14 d and harvested upon reaching an average weight of 113 kg. Average starting body weights were similar between both groups (P = 0.98). Carcass quality was evaluated by measuring pH, loin eye area (LEA), back fat (BF) thickness, subjective color and marbling scores, and colorimetry (CIE color space [L*, a*, b*]) at the 10th rib. Final body weights at slaughter also showed no significant variation between housing groups (P = 0.98). No differences were observed in pork quality: pH 0 h (P = 0.53), 6 h (P = 0.29), 12 h (P = 0.80), and 24 h (P = 0.07) postmortem, LEA (P = 0.44), color (P = 0.73), and marbling (P = 0.40). However, hogs raised indoors had an increase in BF thickness (P = 0.04). Based on this pilot study, outdoor rearing conditions did not have significant impacts on pork quality. Further research will help to determine the impact that rearing scheme has on pH and BF.

Correlation analysis of primal cuts weight, fat contents, and auction prices in Landrace × Yorkshire × Duroc pig carcasses by VCS2000

Currently, in pork auctions in Korea, only carcass weight and backfat thickness provide information on meat quantity, while the production volume of primal cuts and fat contents remains largely unknown. This study aims to predict the production of primal cuts in pigs and investigate how these carcass traits affect pricing. Using the VCS2000, the production of shoulder blade, loin, belly, shoulder picnic, and ham was measured for gilts (17,257 pigs) and barrows (16,365 pigs) of LYD (Landrace × Yorkshire × Duroc) pigs. Single and multiple regression analysis were conducted to analyze the relationship between the primal cuts and carcass weight. The study also examined the correlation between each primal cut, backfat thickness (1st thoracic vertebra backfat thickness, grading backfat thickness, and Multi-brached muscle middle backfat thickness), pork belly fat percentage, total fat yield, and auction price. A multiple regression analysis was conducted between the carcass traits that showed a high correlation and the auction price. After conducting a single regression analysis on the primal cuts of gilt and barrow, all coefficients of determination (R2) were 0.77 or higher. In the multiple regression analysis, the R2 value was 0.98 or higher. The correlation coefficient between the carcass weights and the auction price exceeded 0.70, while the correlation coefficients between the primal cuts and the auction prices were above 0.65. In terms of fat content, the backfat thickness of gilt exhibited a correlation coefficient of 0.70, and all other items had a correlation coefficient of 0.47 or higher. The correlation coefficients between the Forequarter, Middle, and Hindquarter and the auction price were 0.62 or higher. The R2 values of the multiple regression analysis between carcass traits and auction price were 0.5 or higher for gilts and 0.4 or higher for barrows. The regression equations between carcass weight and primal cuts derived in this study exhibited high determination coefficients, suggesting that they could serve as reliable means to predict primal cut production from pig carcasses. Elucidating the correlation between primal cuts, fat contents and auction prices can provide economic indicators for pork and assist in guiding the direction of pig farming.

Association analysis between Acetyl-Coenzyme A Acyltransferase-1 gene polymorphism and growth traits in Xiangsu pigs

Introduction

Acetyl-Coenzyme A Acyltransferase-1 (ACAA1) is a peroxisomal acyltransferase involved in fatty acid metabolism. Current evidence does not precisely reveal the effect of the ACAA1 gene on pig growth performance.

Methods

The present study assessed the mRNA expression levels of the ACAA1 gene in the heart, liver, spleen, lung, kidney of 6-month-old Xiangsu pigs and in the longissimus dorsi muscle at different growth stages (newborn, 6 months and 12 months of age) using RT-qPCR. The relationship between single-nucleotide polymorphisms (SNPs) of ACAA1 gene and growth traits in 6-month-old and 12-month-old Xiangsu pigs was investigated on 184 healthy Xiangsu pigs using Sanger sequencing.

Results

The ACAA1 gene was expressed in heart, liver, spleen, lung, kidney, and longissimus dorsi muscle of 6-month-old pigs, with the highest level of expression in the liver. ACAA1 gene expression in the longissimus dorsi muscle decreased with age (p < 0.01). In addition, four SNPs were identified in the ACAA1 gene, including exon g.48810 A>G (rs343060194), intron g.51546 T>C (rs319197012), exon g.55035 T>C (rs333279910), and exon g.55088 C>T (rs322138947). Hardy-Weinberg equilibrium (p > 0.05) was found for the four SNPs, and linkage disequilibrium (LD) analysis revealed a strong LD between g.55035 T>C (rs333279910) and g.55088 C>T (rs322138947) (r 2 = 1.000). Association analysis showed that g.48810 A>G (rs343060194), g.51546 T>C (rs319197012), g.55035 T>C (rs333279910), and g.55088 C>T (rs322138947) varied in body weight, body length, body height, abdominal circumference, leg and hip circumference and living backfat thickness between 6-month-old and 12-month-old Xiangsu pigs.

Conclusion

These findings strongly demonstrate that the ACAA1 gene can be exploited for marker-assisted selection to improve growth-related phenotypes in Xiangsu pigs and present new candidate genes for molecular pig breeding.

Do carcass traits influence consumer perception of pork eating quality?

The objective of this study was to assess carcass traits' influence on pork eating quality as evaluated by consumers. A total of 1360 pork chops were used, with 824 from the sirloin end and 536 from the butt end of the loin (Longissimuss thoracis et lumborum), to produce 340 packages, each containing four pork chops. Untrained participants received one package of either sirloin or butt chops, being two pork chops from barrows and two from gilts. Participants answered a survey rating the tenderness, juiciness, flavour, and overall acceptability of each chop on an 8-point scale. Correlation analysis was conducted between carcass traits and pork eating quality attributes. For the descriptive analysis, classes (low, medium, and high) for carcass traits, Warner-Bratzler shear force (WBSF) and cooking loss were created based on our consumer responses dataset for palatability attributes. No significant correlations (P > 0.05) were observed between carcass traits and pork eating quality traits. Tenderness and overall acceptability were negatively correlated (P < 0.05) with cooking loss and WBSF. Loin intramuscular fat (IMF) content showed a weak negative correlation (P < 0.05) with WBSF and cooking loss. Consumers rated chops from the high and medium/high backfat thickness and loin IMF classes slightly higher for tenderness and juiciness, respectively. Additionally, chops from the low and/or medium WBSF and cooking loss classes received slightly higher scores for tenderness and juiciness than pork chops in the high classes. In conclusion, the study indicated that carcass traits had minimal impact on overall acceptability of pork by consumers.

Intramuscular fat % in the loin of Australian pork demonstrates a stronger relationship with computed tomography lean and fat % than abattoir measures of P2 and lean

Intramuscular fat (IMF) % is an important measure of pork eating quality, with reduced IMF % linked to the selection of pigs with low backfat P2 thickness and more muscular genotypes over several decades. This experiment tested the association of IMF % from the M. longissimus thoracis et lumborum of 345 pigs at 3 abattoirs (sites) with computed tomography (CT) determined carcass composition (% lean or fat), accredited abattoir measures of P2 backfat (mm; Hennessy Grading Probe [HGP], AutoFom III, and PorkScan Lite) and the lean % output from abattoir devices (HGP, AutoFom III, and PorkScan Plus). There was a negative relationship between carcass CT lean % with IMF % at all sites (P < 0.05), with the strength of this relationship varying between sites. The strongest relationship was demonstrated at site 1 (R2 0.30, RMSE 0.59), and across a 4 SD range in the carcass lean % at each site, resulted in a decrease in loin IMF % of 1.56, 0.44, and 0.80. There was a positive relationship of carcass CT fat % with IMF %, with similar, albeit slightly stronger relationship to IMF than with CT lean %. In contrast, only one of the 3 sites with an accredited P2 measurement device demonstrated a significant association (P < 0.05) with IMF %. This is the first time the associations of IMF % with carcass CT composition has been assessed alongside that of P2 backfat measurements from commercially deployed abattoir devices. Given P2 backfat is the key industry measure on which carcass value is determined in Australia, this experiment demonstrates the limitations that P2 has in measuring and monitoring the associations of carcass lean and fat % with IMF. Ideally, an independent measure of IMF % would allow for independent selection for lean % and IMF %; however, there is currently no commercial device that can measure pork IMF %.

Sow-Offspring Diets Supplemented with Probiotics and Synbiotics Are Associated with Offspring's Growth Performance and Meat Quality

Probiotics and synbiotics supplementation have been shown to play potential roles in animal production. The present study aimed to evaluate the effects of dietary probiotics and synbiotics supplementation to sows during gestation and lactation and to offspring pigs (sow-offspring) on offspring pigs' growth performance and meat quality. Sixty-four healthy Bama mini-pigs were selected and randomly allocated into four groups after mating: the control, antibiotics, probiotics, and synbiotics groups. After weaning, two offspring pigs per litter were selected, and four offspring pigs from two litters were merged into one pen. The offspring pigs were fed a basal diet and the same feed additive according to their corresponding sows, representing the control group (Con group), sow-offspring antibiotics group (S-OA group), sow-offspring probiotics group (S-OP group), and sow-offspring synbiotics group (S-OS group). Eight pigs per group were euthanized and sampled at 65, 95, and 125 d old for further analyses. Our findings showed that probiotics supplementation in sow-offspring diets promoted growth and feed intake of offspring pigs during 95-125 d old. Moreover, sow-offspring diets supplemented with probiotics and synbiotics altered meat quality (meat color, pH_45min, pH_24h, drip loss, cooking yield, and shear force), plasma UN and AMM levels, and gene expressions associated with muscle-fiber types (MyHCI, MyHCIIa, MyHCIIx, and MyHCIIb) and muscle growth and development (Myf5, Myf6, MyoD, and MyoG). This study provides a theoretical basis for the maternal-offspring integration regulation of meat quality by dietary probiotics and synbiotics supplementation.

Effect of non-starch polysaccharide enzyme supplementation with gradually reduced energy diet on growth performance, nutrient digestibility, lean meat percentage and backfat thickness of growing pigs

This study was conducted with the objective of evaluating a way to reduce feed costs with better meat characteristics for growing pigs by supplementing non-starch polysaccharide enzyme (NSPE) in energy reduced diets. A total of 200 growing pigs [(Landrace × Yorkshire) × Duroc] weighing 22.94 ± 0.22 kg were divided into five dietary treatments, each with eight replication pens (three barrows and two gilts). The pigs were allotted in a completely randomised block design according to body weight and sex. The dietary treatments were: CON (control), basal diet (NE 2500 kcal); NSPE1, basal diet + 0.04% NSPE; NSPE2, (basal diet-20 kcal) + 0.04% NSPE; NSPE3, (basal diet-30 kcal) + 0.04% NSPE; NSPE4, (basal diet-50 kcal) + 0.04% NSPE. We have assessed growth performance, lean meat percentage (LMP) and backfat thickness at initial, Week 4 and 8. Apparent nutrient digestibility was assessed in Weeks 4 and 8. There was no significant difference (p > 0.05) among the groups on growth performance. In Week 8, gradual reduction of energy caused a linear reduction (p = 0.028) of backfat thickness and a linear increase (p < 0.05) of LMP. In addition, at Week 8, supplementation of NSPE enzyme showed improved digestibility of nitrogen (p < 0.05) and energy (p < 0.05) in the NSPE1 group than in the CON group. In short, gradual reduction of dietary energy supplemented with NSPE showed consistent growth performance through higher nutrient digestibility with positive changes in backfat thickness and LMP of growing pigs.

Conjugated linoleic acids inhibit lipid deposition in subcutaneous adipose tissue and alter lipid profiles in serum of pigs

Conjugated linoleic acids (CLAs) have served as a nutritional strategy to reduce fat deposition in adipose tissues of pigs. However, the effects of CLAs on lipid profiles in serum and how these lipid molecules regulate fat deposition are still unclear. In this study, we explored the effects of CLAs on regulating lipid deposition in adipose tissues in terms of lipid molecules and microbiota based on a Heigai pig model. A total of 56 Heigai finishing pigs (body weight: 85.58 ± 10.39 kg) were randomly divided into two treatments and fed diets containing 1% soyabean oil or 1% CLAs for 40 d. CLAs reduced fat deposition and affected fatty acids composition in adipose tissues of Heigai pigs via upregulating the expression of the lipolytic gene (hormone-sensitive lipase, HSL) in vivo and in vitro. CLAs also altered the biochemical immune indexes including reduced content of total cholesterol (TChol), high-density lipoprotein (HDL-C), and low-density lipoprotein (LDL-C) and changed lipids profiles including decreased sphingolipids especially ceramides (Cers) and sphingomyelins (SMs) in serum of Heigai pigs. Mechanically, CLAs may decrease peroxisome proliferator-activated receptorγ (PPARγ) expression and further inhibit adipogenic differentiation in adipose tissues of pigs by suppressing the function of Cers in serum. Furthermore, Pearson's correlation analysis showed HSL expression was positively related to short-chain fatty acids (SCFAs) in the gut (P ≤ 0.05) but the abundance of Cers was negatively related to the production and functions of SCFAs (P ≤ 0.05). CLAs altered the distribution of the lipid in serum and inhibited adipogenic differentiation by suppressing the function of Cers and further decreasing PPARγ expression in adipose tissues of Heigai pigs. Besides, the HSL expression and the abundance of Cers are associated with the production and functions of SCFAs in the gut.

Comparison of an advanced automated ultrasonic scanner (AutoFom III) and a handheld optical probe (Destron PG-100) to determine lean yield in pork carcasses

This study compared the accuracy of two methods for predicting carcass leanness (i.e., predicted lean yield) with fat-free lean yields obtained by manual carcass side cut-out and dissection of lean, fat, and bone components. The two prediction methods evaluated in this study estimated lean yield by measuring fat thickness and muscle depth at one location with an optical grading probe (Destron PG-100) or by scanning the entire carcass with advanced ultrasound technology (AutoFom III). Pork carcasses (166 barrows and 171 gilts; head-on hot carcass weights (HCWs) ranging from 89.4 to 138.0 kg) were selected based on their fit within desired HCW ranges, their fit within specific backfat thickness ranges, and sex (barrow or gilt). Data (n = 337 carcasses) were analyzed using a 3 × 2 factorial arrangement in a randomized complete block design including the fixed effects of the method for predicting lean yield, sex, and their interaction, and random effects of producer (i.e., farm) and slaughter date. Linear regression analysis was then used to examine the accuracy of the Destron PG-100 and AutoFom III data for measuring backfat thickness, muscle depth, and predicted lean yield when compared with fat-free lean yields obtained with manual carcass side cut-outs and dissections. Partial least squares regression analysis was used to predict the measured traits from image parameters generated by the AutoFom III software. There were method differences (P < 0.01) for determining muscle depth and lean yield with no method differences (P = 0.27) for measuring backfat thickness. Both optical probe and ultrasound technologies strongly predicted backfat thickness (R2 ≥ 0.81) and lean yield (R2 ≥ 0.66), but poorly predicted muscle depth (R2 ≤ 0.33). The AutoFom III improved accuracy [R2 = 0.77, root mean square error (RMSE) = 1.82] for the determination of predicted lean yield vs. the Destron PG-100 (R2 = 0.66, RMSE = 2.22). The AutoFom III was also used to predict bone-in/boneless primal weights, which is not possible with the Destron PG-100. The cross-validated prediction accuracy for the prediction of primal weights ranged from 0.71 to 0.84 for bone-in cuts and 0.59 to 0.82 for boneless cut lean yield. The AutoFom III was moderately (r ≤ 0.67) accurate for the determination of predicted lean yield in the picnic, belly, and ham primal cuts and highly (r ≥ 0.68) accurate for the determination of predicted lean yield in the whole shoulder, butt, and loin primal cuts.

Exploring a Possible Link between the Fecal Microbiota and the Production Performance of Pigs

The backfat thickness of pigs not only affects the physical properties and taste of meat, but it also closely relates to the reproduction performance of sows. Accumulating evidence indicates that, apart from genetic factors, gut microbiota can also modulate the fat deposition and muscle growth. However, the differential microbiota in pigs with different backfat thickness, and whether microbiota affects backfat thickness, remains elusive. Firstly, 16S ribosomal RNA (16S rRNA) gene sequencing was performed on 62 fecal samples from pigs with different backfat thicknesses, and the compositions of microbiota among different groups with different backfat thicknesses were different. The abundance of Lactobacillus. reuteri (L. reuteri) and Prevotella sp RS2 was significantly higher in pigs with low-backfat thickness than that in pigs with middle and high-backfat thickness; meanwhile, the abundance of Desulfovibrio piger was significantly lower (p < 0.05) in pigs with low-backfat thickness. Furthermore, the functional profiling of microbial communities suggested that the abundance of isoquinoline alkaloid biosynthesis and styrene degradation were significantly lower (p < 0.05) in the low-backfat thickness group than that in middle and high-backfat thickness groups. Finally, L. reuteri fed to Meishan piglets was capable of improving the production performance and had the potential to reduce backfat thickness. This study provides new evidence that microbiota can regulate the phenotype of the host, and dietary supplementation with L. reuteri can improve the production performance of piglets.

Genome-wide association study identifying genetic variants associated with carcass backfat thickness, lean percentage and fat percentage in a four-way crossbred pig population using SLAF-seq technology

Background

Carcass backfat thickness (BFT), carcass lean percentage (CLP) and carcass fat percentage (CFP) are important to the commercial pig industry. Nevertheless, the genetic architecture of BFT, CLP and CFP is still elusive. Here, we performed a genome-wide association study (GWAS) based on specific-locus amplified fragment sequencing (SLAF-seq) to analyze seven fatness-related traits, including five BFTs, CLP, and CFP on 223 four-way crossbred pigs.

Results

A total of 227, 921 highly consistent single nucleotide polymorphisms (SNPs) evenly distributed throughout the genome were used to perform GWAS. Using the mixed linear model (MLM), a total of 20 SNP loci significantly related to these traits were identified on ten Sus scrofa chromosomes (SSC), of which 10 SNPs were located in previously reported quantitative trait loci (QTL) regions. On SSC7, two SNPs (SSC7:29,503,670 and rs1112937671) for average backfat thickness (ABFT) exceeded 1% and 10% Bonferroni genome-wide significance levels, respectively. These two SNP loci were located within an intron region of the COL21A1 gene, which was a protein-coding gene that played an important role in the porcine backfat deposition by affecting extracellular matrix (ECM) remodeling. In addition, based on the other three significant SNPs on SSC7, five candidate genes, ZNF184, ZNF391, HMGA1, GRM4 and NUDT3 were proposed to influence BFT. On SSC9, two SNPs for backfat thickness at 6–7 ribs (67RBFT) and one SNP for CLP were in the same locus region (19 kb interval). These three SNPs were located in the PGM2L1 gene, which encoded a protein that played an indispensable role in glycogen metabolism, glycolysis and gluconeogenesis as a key enzyme. Finally, one significant SNP on SSC14 for CLP was located within the PLBD2 gene, which participated in the lipid catabolic process.

Conclusions

A total of two regions on SSC7 and SSC9 and eight potential candidate genes were found for fatness-related traits in pigs. The results of this GWAS based on SLAF-seq will greatly advance our understanding of the genetic architecture of BFT, CLP, and CFP traits. These identified SNP loci and candidate genes might serve as a biological basis for improving the important fatness-related traits of pigs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08827-8.

Effects of the slaughter weight of non-lean finishing pigs on their carcass characteristics and meat quality

The present study aimed to assess the feasibility of increasing the slaughter weight (SW) of non-lean finishing pigs to improve their meat quality. A total of 36 (Landrace × Yorkshire) × Duroc gilts and barrows were slaughtered at 115 (Av), 125 (Hi), or 135 (XHi) kg, followed by physicochemical analyses and sensory evaluation on their longissimus dorsi (LD) and Semimembranosus (SM) muscles. Backfat thickness was greater (p < 0.05) for the XHi (31.2 mm) and Hi (29.3 mm) groups than for Av (25.0 mm). Dressing percentage and yield of the belly per whole carcass were also slightly greater for XHi and Hi vs. Av. The intramuscular fat (IMF) content of SM was greater for XHi (2.64%) than for Av (1.83%) and Hi (2.04%) and also was correlated with SW (r = 0.55). The pH value, lightness, redness, drip loss, shear force, and moisture and protein contents of LD and SM, as well as IMF content of LD, were unaffected by SW. Percentages of 14:0, 16:0, and total saturated fatty acids (FA) were less for Hi and XHi vs. Av in SM, those of total unsaturated FA, 18:2, 20:4, and n-6 being opposite; FA composition of LM was not influenced by SW except for a reduced 18:0 percentage for XHi vs. Av. The sensory score was less for XHi vs. Av for odor in fresh LD and SM, and less for Hi and XHi vs. Av for aroma in fresh LM; scores for color, drip loss, marbling, and acceptability were unaffected by SW. As for cooked muscles, none of the scores for color, aroma, flavor, juiciness, tenderness, and acceptability was affected by SW, except for a greater LD color score for Hi and XHi vs. Av. Collectively, the results suggested that the increased yield of the carcass and belly due to increased SW is outbalanced negatively by excessive backfat deposition in production efficiency, whereas the SW increase exerts little influence on overall sensory quality of fresh or cooked meat. Production of non-lean market pigs overweighing 115 kg therefore will be uneconomical unless consumers pay a substantial premium for the over-fattened pork.

Characterization of a Read-through Fusion Transcript, BCL2L2-PABPN1, Involved in Porcine Adipogenesis

cis-Splicing of adjacent genes (cis-SAGe) has been involved in multiple physiological and pathological processes in humans. However, to the best of our knowledge, there is no report of cis-SAGe in adipogenic regulation. In this study, a cis-SAGe product, BCL2L2–PABPN1 (BP), was characterized in fat tissue of pigs with RT-PCR and RACE method. BP is an in-frame fusion product composed of 333 aa and all the functional domains of both parents. BP is highly conserved among species and rich in splicing variants. BP was found to promote proliferation and inhibit differentiation of primary porcine preadipocytes. A total of 3074/44 differentially expressed mRNAs (DEmRs)/known miRNAs (DEmiRs) were identified in porcine preadipocytes overexpressing BP through RNA-Seq analysis. Both DEmRs and target genes of DEmiRs were involved in various fat-related pathways with MAPK and PI3K-Akt being the top enriched. PPP2CB, EGFR, Wnt5A and EHHADH were hub genes among the fat-related pathways identified. Moreover, ssc-miR-339-3p was found to be critical for BP regulating adipogenesis through integrated analysis of mRNA and miRNA data. The results highlight the role of cis-SAGe in adipogenesis and contribute to further revealing the mechanisms underlying fat deposition, which will be conductive to human obesity control.