Analysis of Relationships Between Fattening and Slaughter Performance of Pigs and the Level of Intramuscular Fat (IMF) in Longissimus Dorsi Muscle

Evaluation of different percentages of Duroc genes and gender on growth, carcass and meat quality traits for pigs

The effect of different percentages of Duroc genes in crossbreeding (5, 50 and 100%), the gender (immunocastrated males - ICM and females) and their interaction was evaluated on growth, carcass and meat quality traits for pigs. Crossbreds (50% Duroc) had greater average daily feed intake, hot carcass weight and backfat thickness but lower meat yield when compared to 5% Duroc crossbreds and purebred (100% Duroc) animals (P < 0.05). Purebred (100% Duroc) animals had the lowest backfat thickness and subcutaneous fat thickness, and the greatest muscle depth and meat yield (P < 0.05). ICM animals had better feed conversion, greater average daily gain, hot carcass weight and amount of meat, and lower hot carcass yield, cold carcass weight, Longissimus thoracis depth, rib with belly and ham weights compared to females (P < 0.05). Marbling scores were greater in purebred (100%) animals (P < 0.05). The meat from 50% Duroc crossbreds and 100% Duroc purebred pigs was more reddish pink in color than 5% Duroc crossbreds (P < 0.05). Also, marbling scores were greater for females compared to ICM (P < 0.05). Purebred (100% Duroc) animals required more medications during production (P < 0.05).

Variations in Fibrinogen-like 1 (FGL1) Gene Locus as a Genetic Marker Related to Fat Deposition Based on Pig Model and Liver RNA-Seq Data

The goal of this study was to evaluate the effects of mutations in the FGL1 gene associated with pig productive traits to enrich the genetic marker pool for further selection and to support the studies on FGL1 in the context of the fat deposition (FD) process. The variant calling and χ2 analyses of liver RNA-seq data were used to indicate genetic markers. FGL1 mutations were genotyped in the Złotnicka White (n = 72), Polish Large White (n = 208), Duroc (n = 72), Polish Landrace (PL) (n = 292), and Puławska (n = 178) pig breeds. An association study was performed using a general linear model (GLM) implemented in SAS® software. More than 50 crucial mutations were identified in the FGL1 gene. The association study showed a significant effect of the FGL1 on intramuscular fat (IMF), loin eye area, backfat thickness at the lumbar, ham mass (p = 0.0374), meat percentage (p = 0.0205), and loin fat (p = 0.0003). Alternate homozygotes and heterozygotes were found in the PL and Duroc, confirming the selective potential for these populations. Our study supports the theory that liver FGL1 is involved in the FD process. Moreover, since fat is the major determinant of flavor development in meat, the FGL1 rs340465447_A allele can be used as a target in pig selection focused on elevated fat levels.

Association Between ATP Citrate Lyase (ACLY) Gene Polymorphism and Fattening, Slaughter and Pork Quality Traits in Polish Pigs

The primary aim of this study was to estimate the relationship between ATP citrate lyase (ACLY) gene polymorphism (c.*523 T>C) and fattening and pork quality traits. Investigations were carried out on 526 pigs represented by three breeds: Polish Landrace (n=269), Polish Large White (n=189) and Puławska (n=68). ACLY genotypes were determined by PCR–RFLP method. It was demonstrated that the analyzed polymorphism had significant influence (P<0.05 and P≤0.01) on several economically important traits in pigs, e.g. average daily gain, average backfat thickness, lean meat percentage. The results obtained allow for application of c.*523 T>C polymorphism in breeding programs to improve the pig population in terms of fattening and slaughter traits. However, this breeding program may have a slight negative effect on meat texture parameters.

Cold Exposure Affects Lipid Metabolism, Fatty Acids Composition and Transcription in Pig Skeletal Muscle

Cold exposure promotes glucose oxidation and modulates the lipid metabolism in adipose tissue, but it is still not fully clear whether cold exposure could affect meat quality and fatty acid metabolism in skeletal muscle of pig in vivo. Here, we kept finishing pigs under cold or room temperature overnight and determined the effects of cold exposure on meat quality, fatty acids composition and transcriptional changes in skeletal muscle of pigs. We found that cold exposure significantly reduced the meat colour_{24 h} and pH_{24 h}, without affecting carcass characteristics and other meat quality traits. Considerable changes were found in the proportions of individual fatty acids and the total content of saturated fatty acid, polyunsaturated fatty acids, monounsaturated fatty acid and n3-fatty acids. RNA-seq results showed upregulated fatty acid biosynthesis genes and downregulated mitochondrial beta-oxidation genes. The lipid metabolism in cold-treated longissimus dorsi muscle might be regulated by functions of the lipoprotein particle, the extracellular matrix, and the PPAR signaling pathways. Our study revealed the potential of cold exposure to regulate the lipid metabolism and fatty acid composition in skeletal muscle of farmed animals.

Gene expression of fatty acid binding protein genes and its relationship with fat deposition of Thai native crossbreed chickens

Objective

The objectives of this study were to investigate the relationship between the mRNA expression of adipocyte type fatty acid binding protein (A-FABP) and heart type FABP (H-FABP) in Thai native chicken crossbreeds and evaluate the level of exotic inclusion in native chicken that will improve growth while maintaining its relatively low carcass fat.

Methods

The fat deposition traits and mRNA expression of A-FABP and H-FABP were evaluated at 6, 8, 10, and 12 weeks of age in 4 chicken breeds (n = 8/breed/wk) (100% Chee breed [CH] [100% Thai native chicken background], CH male and broiler female [Kaimook e-san1; KM1] [50% CH background], broiler male and KM1 female [Kaimook e-san2; KM2] [25% CH background], and broiler [BR]) using abdominal fat (ABF) and muscular tissues.

Results

The BR breed was only evaluated at 6 weeks of age. At week 6, the CH breed had a significantly lower A-FABP expression in ABF and intramuscular fat (IF) compared with the other breeds. At 8 to 12 weeks, the KM2 groups showed significant upregulation (p<0.05) of A-FABP in both ABF and IF compared to the CH and KM1 groups. The expression of H-FABP did not follow any consistent pattern in both ABF and IF across the different ages.

Conclusion

Some level of crossbreeding CH chickens can be done to improve growth rate while maintaining their low ABF and IF. The expression level of A-FABP correlate with most fat traits. There was no consistency of H-FABP expression across breed. A-FABPs is involved in fat deposition, genetic markers in these genes could be used in marker assisted studies to select against excessive fat accumulation.

Functional Analysis of Genes Involved in Glycerolipids Biosynthesis (GPAT1 and GPAT2) in Pigs

Simple Summary

Pork consumption is the highest among all meats in Poland and in the world. Current breeding programs were designed to obtain high meat content and low levels of fat in pork carcasses. This resulted in a decrease in the quality of meat. Numerous researchers indicated that intramuscular fat content (IMF) is the determining factor for meat quality and consumer’s acceptance of meat. The genes GPAT1 and GPAT2, being the objective of this study are involved in triacylglycerol (TAG) synthesis. TAGs are the main constituents of animal fat as well as of IMF. The aim of this study was to assess the expression level of the GPAT1 and GPAT2 genes in musculus longissimus lumborum, subcutaneous fat and liver of pigs. Moreover, association analysis between the genes’ expression, production traits, quality and sensory parameters of pork was carried out. The results obtained showed significant differences in the mRNA expression of analyzed genes between tissues and breeds of pigs. Furthermore, association analysis showed significant associations between expression level of the genes and some of the production traits, sensory and quality parameters of pork. The results of this study indicated the possibility of modification of desired traits through transcriptional control of gene expression.

Abstract

Glycerol-3-phosphate acyltransferase (GPAT) enzymes catalyze the first step in triacylglycerol (TAG) synthesis. Genes that belong to the GPAT family are potential genetic markers for intramuscular fat content (IMF) content and thus meat quality. The objective of this study was to analyze the expression of GPAT1 and GPAT2 genes in musculus longissimus lumborum, liver and subcutaneous fat of various breeds of pigs. Furthermore, correlations between the genes’ expression abundance and utility traits, meat quality and meat texture parameters of pork were determined. The results obtained showed significant differences in the mRNA level of GPAT1 between analyzed tissues and breeds. The highest expression of GPAT1 gene was observed in liver tissue (p ≤ 0.01). Furthermore, significantly higher GPAT1 transcript level in the m. longissimus lumborum was observed for duroc in comparison to other analyzed breeds (p ≤ 0.05). Expression of the GPAT2 gene was shown only in the liver tissues, however statistically significant differences between the analyzed breeds were not observed. Correlation analysis confirmed the highest association between GPAT2 gene expression level in liver and cohesiveness and resilience traits of m. longissimus lumborum (p ≤ 0.01).

Efficiency of pea seeds in sow, piglet and fattener feeding

Two varieties of pea, one white flowering (cv. Tarchalska) and one colour flowering (cv. Milwa), partly replaced soybean meal in the diet of sows and their progeny, namely, piglets and growing pigs. The effect of a feed enzyme supplement (Ronozyme VP) was also determined Animal performance and carcass and meat quality were estimated using standard methods. There was no significant difference in the sow bodyweight, number of piglets born and litter weight between the treatments. After weaning, bodyweight gains of piglets in all groups were similar. During the fattening periods, the bodyweight gains of the pigs receiving cv. Milwa were significantly higher than those fed with cv. Tarchalska. The bodyweight gains in the control group were intermediate. The enzyme supplement did not improve bodyweight gains. The digestibility of protein (and in the grower period, also crude fibre and N-free extractives) was higher in the pigs receiving cv. Milwa than in those fed with cv. Tarchalska. There was no significant difference in carcass traits, except for the amount of meat in the ham, which was the highest in the control and lowest in the Milwa group. The intramuscular fat of the pigs fed with cv. Milwa contained significantly more of saturated fatty acids and less of unsaturated fatty acids than did both the control and the pigs fed with cv. Tarchalska. The peas had little effect on the physical traits of the meat; they improved its water-holding capacity but did not change its colour and lightness. Cv. Tarchalska significantly lowered all estimated sensory properties. It is concluded that pea seeds, especially the colour-flowering varieties, may be replacements of soybean meal, in moderate amounts, in the whole cycle of pig nutrition.

The Effect of Feeding Native Faba Bean Seeds (Vicia faba L.) to Sows and Supplemented With Enzymes to Piglets and Growing Pigs

The aim of this experiment was to examine the possibility of replacing part of soybean meal in the diets of sows, their piglets and fatteners with two varieties of high- or low-tannin faba bean seed. Twenty-four sows were allocated to 3 groups, 8 animals in each. Control group (C) received standard feed mixture containing soybean meal as the main protein source. Next groups received standard feed mixture in which part of soybean meal was replaced by high-tannin variety Bobas (group HT) or low-tannin variety Kasztelan (group LT). Faba bean was added to diets at the level of 12 and 14% for pregnant and lactating sows, 6% for piglets, and 12 and 16% for fatteners (grower and finisher, respectively). Diets for half piglets and fatteners were supplemented with the enzyme Ronozyme VP. Apparent digestibility of nutrients was evaluated in a parallel experiment, using the same feeds on 18 barrows weighing about 40 kg (grower) and 80 kg (finisher). There was almost no difference in sow reproductive rates, litter weight and body weight of piglets on the first day of life were similar. Until 35 days of age piglets receiving faba bean grew faster than control ones. Control piglets grew fastest from 35 to 84 days of age, but differences were not significant. Enzyme supplement had a positive effect on body weight only from 56 to 84 days of piglet life. Digestibility of nutrients was lower in pigs fed with faba beans, especially in the grower period. Faba bean HT had lower nutrient digestibility in both periods of fattening. Almost all carcass traits were better in control pigs than in those fed with bean variety Bobas. Meat of these pigs had also the lowest content of unsaturated fatty acids and highest atherogenic indices. In sensory evaluation this meat had also the worst smell and taste. It can be stated that faba bean seeds, in moderate amounts, can partially replace soybean meal in feed for pigs, but some lowering of body weight gain and meat quality is possible especially when high-tannin varieties are used.

Identification of differentially expressed genes in longissimus dorsi muscle between Wei and Yorkshire pigs using RNA sequencing

Intramuscular fat (IMF) content is an important trait closely related to meat quality, which is highly variable among pig breeds from diverse genetic backgrounds. High-throughput sequencing has become a powerful technique for analyzing the whole transcription profiles of organisms. In order to elucidate the molecular mechanism underlying porcine meat quality, we adopted RNA sequencing to detect transcriptome in the longissimus dorsi muscle of Wei pigs (a Chinese indigenous breed) and Yorkshire pigs (a Western lean-type breed) with different IMF content. For the Wei and Yorkshire pig libraries, over 57 and 64 million clean reads were generated by transcriptome sequencing, respectively. A total of 717 differentially expressed genes (DEGs) were identified in our study (false discovery rate < 0.05 and fold change > 2), with 323 up-regulated and 394 down-regulated genes in Wei pigs compared with Yorkshire pigs. Gene Ontology analysis showed that DEGs significantly related to skeletal muscle cell differentiation, phospholipid catabolic process, and extracellular matrix structural constituent. Pathway analysis revealed that DEGs were involved in fatty acid metabolism, steroid biosynthesis, glycerophospholipid metabolism, and protein digestion and absorption. Quantitative real time PCR confirmed the differential expression of 11 selected DEGs in both pig breeds. The results provide useful information to investigate the transcriptional profiling in skeletal muscle of different pig breeds with divergent phenotypes, and several DEGs can be taken as functional candidate genes related to lipid metabolism (ACSL1, FABP3, UCP3 and PDK4) and skeletal muscle development (ASB2, MSTN, ANKRD1 and ANKRD2).

CAPN1 gene as a potential marker for growth performance and carcass characteristics in pigs

The calcium-activated neutral proteinase 1 (CAPN1) gene, which encodes µ-calpain, is considered to be associated with the majority of meat-quality traits. The objective of the present study was to evaluate the effect of CAPN1 polymorphism on the most important slaughter, fattening and pork-quality traits. The genotype frequency of g.1429G>A polymorphism was estimated on 860 pigs represented by five breeds (Polish Landrace, Polish Large White, Pietrain, Duroc and Pulawska). In all breeds, the most frequent were pigs with an AA genotype (60–74%), with the exception of Duroc pigs where the largest number of GG animals was observed (14%). The results showed that g.1429G>A polymorphism significantly affected the number of days on test (P ≤ 0.05) and age at slaughter (P ≤ 0.01), the weight of ham and primary cuts (P ≤ 0.05, P ≤ 0.01 respectively), loin eye area (P ≤ 0.01) and average backfat thickness (P ≤ 0.05). The g.1429G>A single-nucleotide polymorphism showed no clear influence on complex pork-quality traits. At the present stage of research, the results obtained allow for the use of g.1429G>A polymorphism in CAPN1 gene as genetic marker in pig selection to improve several slaughter or fattening traits.

Association of H-FABP gene polymorphisms with intramuscular fat content in Three-yellow chickens and Hetian-black chickens

BACKGROUND

To explore the relationship between the heart-type fatty acid binding protein (H-FABP) gene and intramuscular fat (IMF), a polymorphism of the second exon of the H-FABP gene was investigated in 60 Three-yellow chickens (TYCs) and 60 Hetian-black chickens (HTBCs).

RESULTS

The IMF contents of the cardiac, chest and leg muscles in HTBC were increased compared with TYC. Both TYC and HTBC populations exhibited Hardy-Weinberg Equilibrium (HWE) according to the χ(2) test. Three variations of the two birds were detected, namely, G939A, G982A and C1014T. HTBCs with the TT genotypes exhibit increased IMF content in the chest muscles compared with the TC genotype. Thus, the G982A site could be considered a genetic marker for selecting increased IMF content in the chest muscles of HTBC. The correlation coefficients revealed that H-FABP mRNA expression was negatively correlated with the IMF content in the cardiac, chest and leg muscles of HTBC and in the cardiac and chest muscles of TYC. The relative mRNA expression of H-FABP was reduced in the cardiac and leg muscles of HTBC compared with TYC, but this difference was not observed at the protein level, as assessed by Western blot analysis.

CONCLUSIONS

These findings offer essential data that can be useful in the breeding program of HTBC and future research exploring the role of H-FABP in IMF deposition and regulation in chickens.

Identification of Genes Related to Growth and Lipid Deposition from Transcriptome Profiles of Pig Muscle Tissue

Transcriptome profiles established using high-throughput sequencing can be effectively used for screening genome-wide differentially expressed genes (DEGs). RNA sequences (from RNA-seq) and microRNA sequences (from miRNA-seq) from the tissues of longissimus dorsi muscle of two indigenous Chinese pig breeds (Diannan Small-ear pig [DSP] and Tibetan pig [TP]) and two introduced pig breeds (Landrace [LL] and Yorkshire [YY]) were examined using HiSeq 2000 to identify and compare the differential expression of functional genes related to muscle growth and lipid deposition. We obtained 27.18 G clean data through the RNA-seq and detected that 18,208 genes were positively expressed and 14,633 of them were co-expressed in the muscle tissues of the four samples. In all, 315 DEGs were found between the Chinese pig group and the introduced pig group, 240 of which were enriched with functional annotations from the David database and significantly enriched in 27 Gene Ontology (GO) terms that were mainly associated with muscle fiber contraction, cadmium ion binding, response to organic substance and contractile fiber part. Based on functional annotation, we identified 85 DEGs related to growth traits that were mainly involved in muscle tissue development, muscle system process, regulation of cell development, and growth factor binding, and 27 DEGs related to lipid deposition that were mainly involved in lipid metabolic process and fatty acid biosynthetic process. With miRNA-seq, we obtained 23.78 M reads and 320 positively expressed miRNAs from muscle tissues, including 271 known pig miRNAs and 49 novel miRNAs. In those 271 known miRNAs, 20 were higher and 10 lower expressed in DSP-TP than in LL-YY. The target genes of the 30 miRNAs were mainly participated in MAPK, GnRH, insulin and Calcium signaling pathway and others involved cell development, growth and proliferation, etc. Combining the DEGs and the differentially expressed (DE) miRNAs, we drafted a network of 46 genes and 18 miRNAs for regulating muscle growth and a network of 15 genes and 16 miRNAs for regulating lipid deposition. We identified that CAV2, MYOZ2, FRZB, miR-29b, miR-122, miR-145-5p and miR-let-7c, etc, were key genes or miRNAs regulating muscle growth, and FASN, SCD, ADORA1, miR-4332, miR-182, miR-92b-3p, miR-let-7a and miR-let-7e, etc, were key genes or miRNAs regulating lipid deposition. The quantitative expressions of eight DEGs and seven DE miRNAs measured with real-time PCR certified that the results of differential expression genes or miRNAs were reliable. Thus, 18,208 genes and 320 miRNAs were positively expressed in porcine longissimus dorsi muscle. We obtained 85 genes and 18 miRNAs related to muscle growth and 27 genes and 16 miRNAs related to lipid deposition, which provided new insights into molecular mechanism of the economical traits in pig.

Effect of dietary inclusion of a herbal extract mixture and different oils on pig performance and meat quality

The aim of the study was to evaluate the effect of a herbal extract mixture on pig performance and meat quality. The experiment was performed on 60 fatteners (60±0.5-112±2.0kg). Group I (control) was fed with standard feed; groups II and III received the same feed supplemented with 150mg BHT or 500mg of a herbal extract mixture (sage, nettle, lemon balm and coneflower) per kg of feed, respectively. In each group, half of the animals received 4% rapeseed oil, the other half soybean oil. The herbal extracts had no effect on animal performance but significantly improved meat oxidative stability, lowered cholesterol and TI index and increased PUFA content in meat. Slight differences between animals fed with rapeseed or soybean oils were observed. Gilt meat had significantly better (P≤0.01) AI, TI, and h/H indices than barrow meat. It was concluded that herbal extracts have a beneficial effect on pork health-promoting properties due to changes in lipid fraction.