The increased intramuscular fat promoted by dietary lysine restriction in lean but not in fatty pig genotypes improves pork sensory attributes

Marine macroalgae in rabbit feed - Effects on meat quality

The addition of macroalgae to livestock diets has demonstrated to enhance the quality of meat by improving the muscle stability, antioxidant capacity and fatty acid profile. However, information regarding rabbit meat is scarce. This study evaluated the effect of adding 1.025% of different macroalgae, dehydrated and as extracts (Saccharina latissima, Himanthalia elongata and Ulva spp.) to the diet of growing rabbits. Dietary supplementation with the Ulva spp. extract increased the fat content (0.96% vs 0.33% in control group) and the proportion of monounsaturated fatty acids (by 22%; P ≤ 0.022), but did not affect the moisture, protein or ash contents or the physicochemical properties of the rabbit longissiumus lumborum muscle. The antioxidant status of the meat was adequate and was not affected by the dietary supplements. The sensorial properties of the meat were also not affected, and dietary supplementation with both S. latissima and H. elongata actually enhanced the flavour and juiciness of the meat (P ≤ 0.01). Altogether, the study findings indicate that the addition of these sustainable ingredients to rabbit feed did not negatively affect meat quality, and some of them may potentially improve specific characteristics, which could make this meat more attractive to consumers.

Regulatory Effects of 198-bp Structural Variants in the GSTA2 Promoter Region on Adipogenesis in Chickens

Molecular breeding accelerates animal breeding and improves efficiency by utilizing genetic mutations. Structural variations (SVs), a significant source of genetic mutations, have a greater impact on phenotypic variation than SNPs. Understanding SV functional mechanisms and obtaining precise information are crucial for molecular breeding. In this study, association analysis revealed significant correlations between 198-bp SVs in the GSTA2 promoter region and abdominal fat weight, intramuscular fat content, and subcutaneous fat thickness in chickens. High expression of GSTA2 in adipose tissue was positively correlated with the abdominal fat percentage, and different genotypes of GSTA2 exhibited varied expression patterns in the liver. The 198-bp SVs regulate GSTA2 expression by binding to different transcription factors. Overexpression of GSTA2 promoted preadipocyte proliferation and differentiation, while interference had the opposite effect. Mechanistically, the 198-bp fragment contains binding sites for transcription factors such as C/EBPα that regulate GSTA2 expression and fat synthesis. These SVs are significantly associated with chicken fat traits, positively influencing preadipocyte development by regulating cell proliferation and differentiation. Our work provides compelling evidence for the use of 198-bp SVs in the GSTA2 promoter region as molecular markers for poultry breeding and offers new insights into the pivotal role of the GSTA2 gene in fat generation.

Exploration of Microencapsulation of Arginine in Carnauba Wax (Copernicia prunifera) and Its Dietary Effect on the Quality of Beef

The objective of this exploratory study was to assess if microencapsulated arginine influences the physicochemical quality of beef. The study included three genetic groups: Angus, Hereford, and Angus × Hereford crossbreed. Two encapsulation systems were used with carnauba wax, at ratios of 3:1 and 2:1, carnauba wax:core (arginine), respectively. A control treatment was also included with no arginine addition. Encapsulated arginine with a 3:1 ratio increased redness by 19.66 at 28 d aged beef compared to the control and 2:1 ratio with values of 18.55 and 16.77, respectively (p = 0.01). Encapsulated arginine at a 3:1 ratio showed the lowest meat shear force values with 24.32 N at 28 d of ageing (p < 0.001). The Angus breed also had a low value of 24.02 N (p < 0.001). Finally, the highest values of intramuscular fat were observed with the inclusion of arginine in a 3:1 ratio. The fat value reached 2.12% with a 3:1 ratio (p = 0.002), while in the Angus breed it was 1.59%. The addition of carnauba wax-encapsulated arginine can improve meat quality. It enhances red color, tenderness, and marbling in bovine meat.

Nutritional regulation of skeletal muscle energy metabolism, lipid accumulation and meat quality in pigs

The quality of pork determines consumers' purchase intention, which directly affects the economic value of pork. Minimizing the proportion of inferior pork and producing high quality pork are the ultimate goals of the pig industry. Muscle energy metabolism, serving as a regulative hub in organism energy expenditure and storage as a fat deposit, is compatible with myofiber type composition, affecting meat color, intramuscular fat content, tenderness, pH values and drip loss. Increasing data illustrate that dietary nutrients and bioactive ingredients affect muscle energy metabolism, white adipose browning and fat distribution, and myofiber type composition in humans, and rodents. Recently, some studies have shown that modulating muscle energy metabolism and lipid accumulation through nutritional approaches could effectively improve meat quality. This article reviews the progress and development in this field, and specifically discusses the impacts of dietary supply of amino acids, lipids, and gut microbiota as well as maternal nutrition on skeletal muscle energy metabolism, lipid accumulation and meat quality of pigs, so as to provide comprehensive overview with respect to effective avenues for improving meat quality.

Effect of crossbreeding and sex on slaughter performance and meat quality in Xingguo gray goose based on multiomics data analysis

Here, we examined the effects of crossbreeding and sex on growth performance, slaughter performance, and meat quality in Xingguo gray (XG) goose, using transcriptomic and metabolomic techniques. The experiment was conducted using 400 goslings (1-day old) of 2 genotypes: the XG breed and its ternary hybrids [F₂ geese; (XG Goose♂ × Yangzhou Goose♀)♀ × Shitou Goose♂]. The goslings were divided into 4 groups: female XG, male XG, female F₂ geese, and male F₂ geese, and growth parameters were examined at 70 d of age, using 30 birds from each group. Following slaughter, samples of breast and thigh muscles were collected from each group for chemical, metabolome, and transcriptome analyses. Growth rate, live body and slaughter weights, meat chemical composition, and muscle fiber diameter were affected by crossbreeding and sex. Crossbreeding significantly improved the dressing percentage, semieviscerated rate, eviscerated yield, and abdominal fat yield of XG geese. To clarify the potential regulatory network affected by crossbreeding and sex, we used RNA-seq and nontargeted metabolomics to detect changes in male and female goose breast muscle. The transcriptome results showed that there were 534, 323, 297, and 492 differently expressed genes (DEGs) among the 4 comparison groups (XG-Female vs. F₂-Female, XG-Male vs. F₂-Male, F₂-Male vs. F₂-Female, and XG-Male vs. XG-Female, respectively) that were mainly related to muscle growth and development and fatty acid metabolism pathways. A total of 141 significantly differentially accumulated metabolites (DAMs) were enriched in serine and threonine, propionate, and pyruvate metabolism. Finally, we comprehensively analyzed the metabolome and transcriptome data and found that many DEGs and DAMs played crucial roles in lipid metabolism and muscle growth and development. In summary, crossbreeding can improve XG goose production performance and affect breast muscle gene expression and metabolites in both female and male geese.

Nutrition and Flavor Evaluation of Amino Acids in Guangyuan Grey Chicken of Different Ages, Genders and Meat Cuts

The composition and content of amino acids in foodstuffs have a vital impact on the nutritional value and taste. With the aim of understanding the nutrition and flavor of Guangyuan grey chicken, the composition and content of amino acids in the pectoralis and thigh muscle of chickens at the age of 90 d, 120 d and 150 d were determine using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and an amino acid analyzer. A total of 17 amino acids were detected both in pectoralis and thigh muscle via the amino acid analyzer, of which the content of glutamate was the highest. Additionally, 21 deproteinized free amino acids were detected via LC-MS/MS. Among all samples, the content of glutamine in thigh muscle was the highest. The content of histidine in the pectoralis was the highest. In terms of the flavor amino acids (FAAs), the umami-taste and sweet-taste amino acids were higher in the thigh muscle of 120 d male chicken. From the perspective of protein nutrition, the essential amino acid was higher in pectoral muscle, and the composition was better. The results of the amino acid score showed that the content of leucine and valine were inadequate in Guangyuan grey chicken. Collectively, the content of amino acid in Guangyuan grey chicken was affected by age, gender and meat cut. This study confirms that meat of chicken in different ages, genders, and cuts presents different nutritional values and flavors owing to the variation of amino acids content.

Influence of Sugar Beet Pulp Supplementation on Pigs’ Health and Production Quality

Fibrous feedstuffs can have a variable effect on pig growth, health and meat quality. The effect of sugar beet pulp (SBP) supplementation in the diet on pork quality has not been widely reported. This study examines the effect of an SBP-supplemented (3%) diet (TG-I group) on 300 Large White/Norwegian Landrace pigs in terms of growth performance, blood parameters, microbial profiling of faeces, carcass parameters and meat quality, including the profiles of biogenic amines (BAs), fatty acids (FAs) and volatile compounds (VCs). After 163 days of the experiment, TG-I pigs had a significantly lower average daily gain and feed conversion ratio than pigs in the control group, as well as a significantly higher percentage of carcasses in the S and KN classes and a lower percentage in the E and U classes (p ≤ 0.05). Faeces of TG-I contained significantly more bacteria that are considered probiotic. Significant differences (p ≤ 0.05) were found in most of the blood parameters, FA, VC profile and emotional responses between the two groups. Higher drip loss, protein content and redness, as well as lower cooking loss, intramuscular fat content and lightness were observed in the meat of TG-I. Most of the sensory properties, as well as overall acceptability, were rated higher for the meat of TG-I. Based on the results, a diet containing 3% of SBP could be beneficial for the improvement of pigs’ gut health and pork quality. However, further studies are needed to indicate which compounds of the SBP dietary fiber are responsible for these desirable changes.

Copy Number Variations Contribute to Intramuscular Fat Content Differences by Affecting the Expression of PELP1 Alternative Splices in Pigs

Simple Summary

Copy number variation (CNV) is a type of variant that may influence meat quality of, for example intramuscular fat (IMF). In this study, a genome-wide association study (GWAS) was then performed between CNVs and IMF in a pig F2 resource population. A total of 19 CNVRs were found to be significantly associated with IMF. RNA-seq and qPCR validation results indicated that CNV150, which is located on the 3′UTR end of the proline, as well as glutamate and the leucine rich protein 1 (PELP1) gene may affect the expression of PELP1 alternative splices. We infer that the CNVR may influence IMF content by regulating the alternative splicing of the PELP1 gene and ultimately affects the structure of the PELP1 protein. These findings suggest a novel mechanistic approach for meat quality improvement in animals and the potential treatment of insulin resistance in human beings.

Abstract

Intramuscular fat (IMF) is a key meat quality trait. Research on the genetic mechanisms of IMF decomposition is valuable for both pork quality improvement and the treatment of obesity and type 2 diabetes. Copy number variations (CNVs) are a type of variant that may influence meat quality. In this study, a total of 1185 CNV regions (CNVRs) including 393 duplicated CNVRs, 432 deleted CNVRs, and 361 CNVRs with both duplicated and deleted status were identified in a pig F2 resource population using next-generation sequencing data. A genome-wide association study (GWAS) was then performed between CNVs and IMF, and a total of 19 CNVRs were found to be significantly associated with IMF. QTL colocation analysis indicated that 3 of the 19 CNVRs overlapped with known QTLs. RNA-seq and qPCR validation results indicated that CNV150, which is located on the 3′UTR end of the proline, as well as glutamate and the leucine rich protein 1 (PELP1) gene may affect the expression of PELP1 alternative splices. Sequence alignment and Alphafold2 structure prediction results indicated that the two alternative splices of PELP1 have a 23 AA sequence variation and a helix-fold structure variation. This region is located in the region of interaction between PELP1 and other proteins which have been reported to be significantly associated with fat deposition or insulin resistance. We infer that the CNVR may influence IMF content by regulating the alternative splicing of the PELP1 gene and ultimately affects the structure of the PELP1 protein. In conclusion, we found some CNVRs, especially CNV150, located in PELP1 that affect IMF. These findings suggest a novel mechanistic approach for meat quality improvement in animals and the potential treatment of insulin resistance in human beings.

Estimation of discrimination threshold for emulsified chicken oil in chicken broth

Although fat content affects the texture and flavor of meat and meat products, the fat discrimination thresholds are unknown. This study aimed to elucidate the discrimination threshold of fat in meat products using broth from chicken thigh meat as a meat taste model. In Experiment 1, triangle tests were conducted between 1%, 0.2%, 0.04%, and 0.008% (w/v) chicken oil-supplemented broth and broth without chicken oil. The results indicated the discrimination threshold to be between 0.04% and 0.008% (w/v). In Experiment 2, similar triangle tests were conducted using oil supplementation at 0.1%, 0.0333%, 0.0111%, and 0.0037% to refine the discrimination threshold. Logistic regression analysis revealed that the discrimination threshold of emulsified chicken oil in chicken broth was 0.0387% (w/v). We demonstrated that chicken oil made a sensory difference in chicken broth at a low concentration and indicates that the chicken oil strongly affects the sensory characteristics of chicken broth.

Genes Related to Fat Metabolism in Pigs and Intramuscular Fat Content of Pork: A Focus on Nutrigenetics and Nutrigenomics

Simple Summary

The intramuscular fat (IMF) or marbling is an essential pork sensory quality that influences the preference of the consumers and premiums for pork. IMF is the streak of visible fat intermixed with the lean within a muscle fibre and determines sensorial qualities of pork such as flavour, tenderness and juiciness. Fat metabolism and IMF development are controlled by dietary nutrients, genes, and their metabolic pathways in the pig. Nutrigenetics explains how the genetic make-up of an individual pig influences the pig’s response to dietary nutrient intake. Differently, nutrigenomics is the analysis of how the entire genome of an individual pig is affected by dietary nutrient intake. The knowledge of nutrigenetics and nutrigenomics, when harmonized, is a powerful tool in estimating nutrient requirements for swine and programming dietary nutrient supply according to an individual pig’s genetic make-up. The current paper aimed to highlight the roles of nutrigenetics and nutrigenomics in elucidating the underlying mechanisms of fat metabolism and IMF deposition in pigs. This knowledge is essential in redefining nutritional intervention for swine production and the improvement of some economically important traits such as growth performance, backfat thickness, IMF accretion, disease resistance etc., in animals.

Abstract

Fat metabolism and intramuscular fat (IMF) are qualitative traits in pigs whose development are influenced by several genes and metabolic pathways. Nutrigenetics and nutrigenomics offer prospects in estimating nutrients required by a pig. Application of these emerging fields in nutritional science provides an opportunity for matching nutrients based on the genetic make-up of the pig for trait improvements. Today, integration of high throughput “omics” technologies into nutritional genomic research has revealed many quantitative trait loci (QTLs) and single nucleotide polymorphisms (SNPs) for the mutation(s) of key genes directly or indirectly involved in fat metabolism and IMF deposition in pigs. Nutrient–gene interaction and the underlying molecular mechanisms involved in fatty acid synthesis and marbling in pigs is difficult to unravel. While existing knowledge on QTLs and SNPs of genes related to fat metabolism and IMF development is yet to be harmonized, the scientific explanations behind the nature of the existing correlation between the nutrients, the genes and the environment remain unclear, being inconclusive or lacking precision. This paper aimed to: (1) discuss nutrigenetics, nutrigenomics and epigenetic mechanisms controlling fat metabolism and IMF accretion in pigs; (2) highlight the potentials of these concepts in pig nutritional programming and research.

Consequences of a low protein diet on the liver and longissimus dorsi transcriptome of Duroc × Iberian crossbred pigs

Low protein diets supplied during the growing period of pigs can diminish their growth rate and increase the intramuscular fat (IMF) content which affects the sensorial and technological characteristics of the products. In the present study, the effects of a low protein diet supplied during the growing period of Duroc × Iberian crossbred pigs on several phenotypic traits and on liver and longissimus dorsi transcriptome were analysed at the beginning (EARLY) and at the end (LATE) of the growing period. Two experimental groups of 10 crossbred pigs each were fed two isocaloric diets with different protein content: control diet (C) with 16.5% protein and 0.8% lysine and low protein diet (LP) with 11% CP and 0.6% lysine. Animals fed LP diet have a slower growth than those fed C diet, but no effect of LP diet was observed on the IMF content. The transcriptomes of liver and longissimus dorsi were characterised and quantified through RNA-sequencing (RNA-seq). In liver, 134 and 480 differentially expressed annotated genes and new isoforms (DEGs) were detected between C and LP diets for EARLY and LATE animals, respectively. In muscle, 128 and 68 DEGs were detected at EARLY and LATE time-points. Functional interpretation revealed that LP diet may inhibit immune system molecules and processes in both tissues at EARLY stage. In liver, the DEGs mainly affect lipid and cholesterol metabolic processes, while in muscle, the expression changes would be involved in growth, development and meat quality. In conclusion, a low protein diet supplied during the growing period seems to slow down the growth of Duroc × Iberian crossbred pigs, but it also seems to affect multiple biological processes that could compromise the immune system of Duroc × Iberian crossbred pigs. Therefore, these results question the adequacy of this type of regime in Duroc × Iberian pigs that must be studied in greater depth before being implemented.

GOT1 regulates adipocyte differentiation by altering NADPH content

Objective

This study was performed to examine whether the porcine glutamic-oxaloacetic transaminase 1 (GOT1) gene has important functions in regulating adipocyte differentiation.

Methods

Porcine GOT1 knockout and overexpression vectors were constructed and transfected into the mouse adipogenic 3T3-L1 cells. Lipid droplets levels were measured after 8 days of differentiation. The mechanisms through which GOT1 participated in lipid deposition were examined by measuring the expression of malate dehydrogenase 1 (MDH1) and malic enzyme (ME1) and the cellular nicotinamide adenine dinucleotide phosphate (NADPH) content.

Results

GOT1 knockout significantly decreased lipid deposition in the 3T3-L1 cells (p< 0.01), whereas GOT1 overexpression significantly increased lipid accumulation (p<0.01). At the same time, GOT1 knockout significantly decreased the NADPH content and the expression of MDH1 and ME1 in the 3T3-L1 cells. Overexpression of GOT1 significantly increased the NADPH content and the expression of MDH1 and ME1, suggesting that GOT1 regulated adipocyte differentiation by altering the NADPH content.

Conclusion

The results preliminarily revealed the effector mechanisms of GOT1 in regulating adipose differentiation. Thus, a theoretical basis is provided for improving the quality of pork and studies on diseases associated with lipid metabolism.

Effect of Immunocastration and Diet on Growth Performance, Serum Metabolites and Sex Hormones, Reproductive Organ Development and Carcass Quality of Heavy Gilts

It is desirable to increase fatness in gilts destined for Teruel dry-cured ham production. A total of 192 Duroc × (Landrace × Large White) gilts of 40.3 ± 4.80 kg body weight (BW) were used to assess the impact of immunocastration and feeding on growth performance, serum metabolites and sex hormones, reproductive organ development, and carcass quality. Six treatments were arranged factorially (2 × 3) with two types of gilt (entire gilts (EG) vs. immunocastrated gilts (IG)) and three experimental diets (control vs. high energy vs. low crude protein and amino acids) provided from 76 to 134 kg BW (n = 4 per treatment, being the replicate the pen with eight pigs). Immunocastration was carried out at 58 and 77 kg BW. The IG grew faster and showed lighter reproductive tracts and greater fatness than EG. The experimental feeds had limited effect on carcass quality, but the high-energy diet improved gain-to-feed ratio and the low-protein and -amino-acids diet did not impair growth performance. In conclusion, immunocastration was a better strategy than the tested diets to increase the fatness of gilts intended for Teruel dry-cured ham, although increasing energy or decreasing crude protein and amino acid levels in the diet could be beneficial strategies for pig farmers.

Feeding a high oleic acid (C18:1) diet improves pleasing flavor attributes in pork

One of the main drivers in consumer meat choice is flavor with some pleasing flavor attributes associated with high oleic acid (C18:1) content in the intramuscular fat. This project aimed to produce pork with a distinctively pleasant bouquet by feeding C18:1 rich macadamia oil compared to corn oil. The project also tested three feed formulations based on cereals and pulses representing different pork producing areas: corn/soy (CS), sorghum-lupins (SL), or wheat/canola (WC). Compared to corn oil, feeding macadamia oil resulted in a significant increase in the C18:1 content in pork loin (longissimus dorsi) with the CS showing a higher impact than the WC diets. Pork loins from the two CS-based groups (CS-Corn and CS-Macadamia) were selected for a consumer sensory study involving 82 panelists (39 of Chinese background). Across ethnic backgrounds the taste of high C18:1 pork resulted in the highest hedonic values.

IRLnc: a novel functional noncoding RNA contributes to intramuscular fat deposition

Background

Intramuscular fat (IMF) is associated with meat quality and insulin resistance in animals. Research on genetic mechanism of IMF decomposition has positive meaning to pork quality and diseases such as obesity and type 2 diabetes treatment. In this study, an IMF trait segregation population was used to perform RNA sequencing and to analyze the joint or independent effects of genes and long intergenic non-coding RNAs (lincRNAs) on IMF.

Results

A total of 26 genes including six lincRNA genes show significantly different expression between high- and low-IMF pigs. Interesting, one lincRNA gene, named IMF related lincRNA (IRLnc) not only has a 292-bp conserved region in 100 vertebrates but also has conserved up and down stream genes (< 10 kb) in pig and humans. Real-time quantitative polymerase chain reaction (RT-qPCR) validation study indicated that nuclear receptor subfamily 4 group A member 3 (NR4A3) which located at the downstream of IRLnc has similar expression pattern with IRLnc. RNAi-mediated loss of function screens identified that IRLnc silencing could inhibit both of the RNA and protein expression of NR4A3. And the in-situ hybridization co-expression experiment indicates that IRLnc may directly binding to NR4A3. As the NR4A3 could regulate the catecholamine catabolism, which could affect insulin sensitivity, we inferred that IRLnc influence IMF decomposition by regulating the expression of NR4A3.

Conclusions

In conclusion, a novel functional noncoding variation named IRLnc has been found contribute to IMF by regulating the expression of NR4A3. These findings suggest novel mechanistic approach for treatment of insulin resistance in human beings and meat quality improvement in animal.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-020-07349-5.

Variations in growth performance, meat quality and consumer preferences influenced by difference of breed in buffalo bulls (Bubalus bubalis)

Context Breeds of buffalo (Nili-Ravi and Kundhi) show different growth-rate and meat characteristics. Consumer preferences vary for the selection of meat according to the taste and sensory attributes. Buffalo meat is widely consumed in Asia and multiple buffalo breeds are reared for meat production. Aims The current experiment was designed to compare growth rates, meat characteristics and consumer preference for meat from bulls of different buffalo breeds. Methods Thirty-five male Nili-Ravi buffalo bulls (NRBB) and 35 male Kundhi buffalo bulls (KBB) having an age of 18 ± 1.56 months and 18 ± 1.65 months with live bodyweight of 150 ± 1.98 kg and 149 ± 2.09 kg respectively, were purchased and reared for 90 days. All animals were slaughtered on the 91st day and samples from M. pectoralis descendance, M. latissimus dorsi and M. obliquus externus abdominis were collected. A consumer preference survey was also conducted to assess the preferences for meat from the buffalo breeds. Key results Results of the survey suggested that for buyers, meat colour was the primary selection criteria (P &lt; 0.05) at the time of purchase. Consumers preferred the lighter-coloured meat of KBB (P &lt; 0.05) than that of NRBB. Conclusions Findings of the study showed that meat from KBB had superior sensory attributes compared with NRBB, although the meat from NRBB was the more nutritious of the two buffalo breeds. Implications The results will provide a focussed view regarding selection of buffalo bulls for meat production.

A High Dietary Incorporation Level of Chlorella vulgaris Improves the Nutritional Value of Pork Fat without Impairing the Performance of Finishing Pigs

Simple Summary

Pork is one of the most consumed meats worldwide but its production and quality are facing significant challenges, including feeding sustainability and the unhealthy image of fat. In fact, corn, and soybean, the two main conventional feedstuffs for pig production, are in unsustainable competition with the human food supply and biofuel industry. Moreover, the nutritional value of pork lipids is small due to their low contents of the beneficial n-3 polyunsaturated fatty acids and lipid-soluble antioxidants. The inclusion of microalgae in pig diets represents a promising approach for the development of sustainable pork production and the improvement of its quality. The current study aimed to investigate the impact of Chlorella vulgaris as ingredient (5% in the diet), alone and in combination with carbohydrases, on growth performance, carcass characteristics and pork quality traits in finishing pigs. Our data indicate that the use of 5% C. vulgaris in finishing pig diets does not impair animal growth and ameliorates the nutritional value of pork. Therefore, C. vulgaris could be used advantageously as an alternative sustainable ingredient in swine feeding.

Abstract

The influence of a high inclusion level of Chlorella vulgaris, individually and supplemented with two carbohydrase mixtures, in finishing pig diets was assessed on zootechnical performance, carcass characteristics, pork quality traits and nutritional value of pork fat. Forty crossbred entire male pigs, sons of Large White × Landrace sows crossed with Pietrain boars, with an initial live weight of 59.1 ± 5.69 kg were used in this trial. Swines were randomly assigned to one of four dietary treatments (n = 10): cereal and soybean meal-based diet (control), control diet with 5% C. vulgaris (CV), CV diet supplemented with 0.005% Rovabio^® Excel AP (CV + R) and CV diet supplemented with 0.01% of a four-CAZyme mixture (CV + M). Animals were slaughtered, after the finishing period, with a BW of 101 ± 1.9 kg. Growth performance, carcass characteristics and meat quality traits were not influenced (p > 0.05) by the incorporation of C. vulgaris in the diets. However, the inclusion of the microalga in finishing pig diets increased some lipid-soluble antioxidant pigments and n-3 PUFA, and decreased the n-6:n-3 ratio of fatty acids, thus ameliorating the nutritional value of pork fat. Moreover, the supplementation of diets with the carbohydrase mixtures did not change (p > 0.05) neither animal performance nor meat quality traits, indicating their inefficacy in the increase of digestive utilization of C. vulgaris by pigs under these experimental conditions. It is concluded that the use of C. vulgaris in finishing pig diets, at this high incorporation level, improves the nutritional value of pork fat without compromising pig performance.

Identification of Candidate Circular RNAs Underlying Intramuscular Fat Content in the Donkey

Intramuscular fat (IMF) content is a crucial indicator of meat quality. Circular RNAs (circRNAs) are a large class of endogenous RNAs that are involved in many physiological processes. However, the expression and function of circRNA in IMF in the donkey remains unresolved. Here we performed an expression profiling of circRNAs in the donkey longissimus dorsi muscle and identified 12,727 candidate circRNAs. Among these, 70% were derived from the exons of protein genes. Furthermore, a total of 127 differentially expressed (DE) circRNAs were identified in high (H) and low (L) IMF content groups, including 63 upregulated and 64 downregulated circRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the host genes of the DE circRNAs showed that the host genes were enriched in lipid metabolism related GO terms (e.g., fatty acid beta-oxidation using acyl-CoA dehydrogenase and MLL3/4 complex), and signaling pathways (e.g., TGF-beta and lysine degradation signaling pathway). Further analyses indicated that 127 DE circRNAs were predicted to potentially interact with miRNAs, leading to the construction of circRNA-miRNA regulatory network. Multiple circRNAs can potentially function as sponges of miRNAs that regulate the differentiation of adipocytes. Our results provide valuable expression profile information for circRNA in the donkey and new insight into the regulatory mechanisms of circRNAs in the regulation of IMF content.

Effects of marketable ages on meat quality through fiber characteristics in the goose

Goose meat is increasingly popular among consumers because of its good quality. The fiber characteristics have been well demonstrated to be key contributing factors of meat quality, and the marketable ages are also closely related to meat quality. However, little is known about the effect of different marketable ages on the quality of goose meat through its fiber characteristics. Here, fiber characteristics of Yangzhou geese of different marketable ages (70, 90, and 120 d) and their effect on meat quality were investigated. The results showed that only fast-twitch fibers were present in breast muscle, irrespective of age, and that few slow-twitch fibers could be identified in leg muscle, especially in gastrocnemius and extensor digitorum longus. Fiber diameter in breast muscle increased rapidly from age 70 d to 90 d, from 19.88 to 26.27 μm, and remained stable for 90 d thereafter. The diameter and cross-sectional area of muscle fiber continue to grow with day increasing in leg muscle. In addition, we measured the proximate composition and physical properties at different ages. Among the 3 marketable ages investigated, the 120-day-old geese had higher intramuscular fat and protein content, as well as lower moisture content, both in breast and leg meat. Greater lightness and pressing loss, with lower redness and shear force, were observed in the breast and leg meat of 70-day-old geese when compared with 90- or 120-day-old geese. Taken together, although older marketable age hardly affected muscle fiber type in geese, it would contribute to larger muscle fiber area, higher intramuscular fat and protein content, as well as redder and chewier meat. As a result, the reasonable marketable age should be taken into account to improve quality in goose meat production, and the marketable age of 90 or 120 d was recommended and it could potentially improve meat quality in goose meat production.

Effect of dietary inclusion of Spirulina on production performance, nutrient digestibility and meat quality traits in post-weaning piglets

The effect of Spirulina (Arthrospira platensis), individually or in combination with two commercial carbohydrases, in piglet diets was assessed on growth performance, nutrient digestibility and meat quality traits. Forty post-weaned male piglets from Large White × Landrace sows crossed with Pietrain boars with an initial live weight of 12.0 ± 0.89 kg were used. Piglets were assigned to one of four dietary treatments (n = 10): cereal and soya bean meal base diet (control), base diet with 10% Spirulina (SP), SP diet supplemented with 0.005% Rovabio^® Excel AP (SP + R) and SP diet supplemented with 0.01% lysozyme (SP + L). Animals were slaughtered after a 4-week experimental period. Growth performance was negatively affected by the incorporation of Spirulina in the diets, with an average decrease of 9.1% on final weight, in comparison with control animals. Total tract apparent digestibility (TTAD) of crude protein was higher (p < .05) in the control group than in other groups. In addition, lysozyme increased TTAD of crude fat and acid detergent fibre, relative to the SP and control groups, respectively. In addition, the incorporation of Spirulina, individually and supplemented with enzymes, did not impair meat quality traits. Surprisingly, no protective effect against lipid oxidation was observed with the inclusion of Spirulina in pork after 7 days of storage. This study indicates that growth performance of post-weaning piglets was impaired by the incorporation of 10% Spirulina in the diets, which is mediated by an increase in digesta viscosity and a lower protein digestibility, as a consequence of the resistance of microalga proteins to the action of endogenous peptidases. In addition, it also indicates that lysozyme, in contrast to Rovabio^® Excel AP, is efficient in the degradation of Spirulina cell wall in piglet's intestine. However, the digestion of proteins liberated by Spirulina cell wall disruption is still a challenge.

Free-Range and Low-Protein Concentrated Diets in Iberian Pigs: Effect on Plasma Insulin and Leptin Concentration, Lipogenic Enzyme Activity, and Fatty Acid Composition of Adipose Tissue

The purpose of this study was to investigate the effect of diets with different protein contents on carcass traits, plasma hormone concentration, lipogenic enzyme activities, and fatty acid (FA) composition in the adipose tissue of Iberian pigs. Twenty-four castrated male Iberian pigs (eight per feeding diet) were fed under free-range conditions with acorns and grass (FR), and in confinement with concentrated diets with standard (SP) and low-protein contents (LP) from 116.0 to 174.2 kg live weight. Backfat thickness was not affected by diet. The plasma leptin concentration was higher (p < 0.001) in the FR group than in the LP and SP groups, while insulin concentration was higher in the SP group than in the LP and FR groups. The lipogenic enzyme activities of glucose-6-phosphate dehydrogenase, malic enzyme, and glycerol-3-phosphate dehydrogenase were lower in the FR group compared to the LP and SP pigs. The activities of these enzymes were adipose-tissue-specific. No differences were found in FA composition of adipose tissue between the SP and LP groups, while the FR pigs had lower proportions of saturated FA and higher proportions of monounsaturated and polyunsaturated FA than the SP and LP pigs. In conclusion, feeding low-protein diets in Iberian pigs does not seem to affect adipose carcass traits, strengthening previous findings that indicate that this is a good strategy to improve meat and dry-cured product quality.

Comparison of growth performances, carcass characteristics, and meat qualities of Okinawan indigenous Agu pigs and crossbred pigs sired by Agu or Duroc boar

Indigenous Okinawa Agu pigs are crossed with Large White × Landrace (WL) pigs to improve their meat production, but there is little information regarding the crossbreeding effects. The study aims to compare growth, carcass characteristics, and meat qualities of Agu pigs with those of WL crossbreeds with Agu sires (WLA) or Duroc sires (WLD). WLA pigs showed better growth performance and carcass characteristics and less intramuscular fat (IMF) contents than Agu ones, but they had higher fat deposition, smaller longissimus dorsi muscle area, and higher IMF contents than WLD pigs. Agu pigs showed higher water holding capacity than the other two breeds. The inner layer of Agu backfat contains higher and lower proportions of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acid (PUFA), respectively, than that in WLD animals. WLA animals had intermediate values for the fatty acid content in the inner backfat, although MUFA contents were equal to those of Agu pigs. Fatty acid profiles in IMF were similar to those in the backfat. These results indicate that crossbreeding of Agu with WL pigs improves growth performance and carcass quality. Particularly, WLA pigs have higher IMF contents and MUFA concentrations and lower PUFA concentrations than WLD pigs.

Differential DNA methylation analysis across the promoter regions using methylated DNA immunoprecipitation sequencing profiling of porcine loin muscle

Background and Aim:

Pork leanness and marbling are among the essential traits of consumer preference. To acquire knowledge about universal epigenetic regulations for improving breed selection, a meta-analysis of methylated DNA immunoprecipitation sequencing (MeDIP-seq) profiling data of mixed loin muscle types was performed in this study.

Materials and Methods:

MeDIP-seq profiling datasets of longissimus dorsi muscle and psoas major muscles from male and female pigs of Landrace and Tibetan breeds were preprocessed and aligned to the porcine genome. Analysis of differential methylated DNA regions (DMRs) between the breeds was performed by focusing on transcription start sites (TSSs) of known genes (−20,000-3000 bases from TSS). All associated genes were further reviewed for their functions and predicted for transcription factors (TF) possibly associated with their TSSs.

Results:

When the methylation levels of DMRs in TSS regions of Landrace breed were compared to those of Tibetan breed, 10 DMRs were hypomethylated (Landrace < Tibetan), and 19 DMRs were hypermethylated (Landrace > Tibetan), accordingly (p≤0.001). According to the reviews about gene functions, all associated genes were pieces of evidence for their roles in a variety of muscle and lipid metabolisms. Prediction of the binding TFs revealed the six most abundant binding TFs to such DMRs-associated TSS (p≤0.0001) as follows: ZNF384, Foxd3, IRF1, KLF9, EWSR1-FLI1, HES5, and TFAP2A.

Conclusion:

Common DMRs-associated TSS between the lean-type and the marbled-type loin muscles were identified in this study. Interestingly, the genes associated with such regions were strongly evidenced for their possible roles on the muscle trait characteristics by which further novel research topics could be focused on them in the future.

Integrating RNA-sequencing and untargeted LC-MS metabolomics to evaluate the effect of lysine deficiency on hepatic functions in Holstein calves

Lysine (Lys) is majorly metabolized in the liver. The liver functional consequences of a dietary Lys deficiency in young Holstein calves are unknown. This study aimed to investigate the effects of Lys deficiency in Holstein calf livers using RNA-sequencing and untargeted LC-MS metabolomics. Calves (n = 36; initial body weight 101.2 ± 10.8 kg; 90-day-old) were fed restricted diets, for 90 days, containing 19.2% crude protein that varied in Lys content (PC group 1.21%; PC-Lys group 0.85%; dry matter basis) for 90 days. Body weight, average daily gain, gain/feed, and Lys intake were significantly decreased in response to Lys deficiency (P < 0.05). Dry matter intake was not altered (P > 0.05). Network and pathway analyses revealed that noradrenaline, adenosine 5'-monophosphate, acetyl-CoA, and coenzyme A were significantly decreased. Regulating of lipolysis in adipocytes pathway and fatty acid degradation pathway were downregulated. We also identified eight significantly differentially expressed genes (SDEGs), among which adrenoceptor beta 2 (ADRB2), WAP four-disulfide core domain 2 (WFDC2), and claudin-4 (CLDN4) were associated with inhibition of lipolysis, and carbon catabolite repression 4-like (CCRN4L), FOS like 2 (FOSL2), and arginase 2 (ARG2) were associated with inhibiting lipid synthesis. Correlation tests showed that coenzyme A was strongly correlated with SDEGs (0.82 ≤|r|≤ 0.96). Acetyl-CoA and adenosine 5'-monophosphate were strongly correlated with CCRN4L (0.90 ≤|r|≤ 0.92), indicating a strong correlation between the changes in SDEGs and these metabolites. In conclusion, Lys deficiency caused dysplasia and affected lipid metabolism in the liver by inhibiting lipolysis and lipid synthesis in calves.

Effects of genetic selection and threonine on meat quality in Pekin ducks

The present study was conducted to investigate the effects of genetic selection and threonine levels on meat quality in Pekin ducks. At 15 D of age, 192 lean ducks and 192 fatty ducks were selected and allotted to one of three treatments with 8 replicates with similar BW (8 ducks/cage), respectively. All ducks were fed the experimental diets (0.00, 0.15, and 0.30% added threonine) for 21 D from 15 to 35 D of age. The results showed that fatty ducks had higher (P < 0.001) feed intake, feed/gain ratio, abdominal fat percentage, and sebum percentage and lower (P = 0.001) breast muscle percentage compared with that of lean ducks. The fatty-type and lean-type ducks had similar weight gain and BW. Dietary threonine supplementation improved (P < 0.05) growth performance and increased breast muscle percentage in lean-type ducks, but it did not affect (P > 0.05) those indices in fatty-type ducks. Lean ducks had higher (P < 0.001) hepatic contents of total lipids, triglyceride, cholesterol, and plasma low-density lipoprotein cholesterol concentration, and dietary threonine supplementation decreased (P < 0.05) hepatic total lipid, cholesterol, and triglyceride contents in lean ducks, but it had no influence on hepatic lipids in fatty ducks (P > 0.05). Lean ducks had higher (P < 0.05) concentrations of monounsaturated fatty acid (MUFA), and C18-polyunsaturated fatty acid (PUFA) in the liver, PUFA in the breast muscle, and C18:3n6 and C18:3n3 in plasma and lower C20-PUFA and C22-PUFA in the liver and MUFA in plasma, compared with fatty ducks. Threonine supplementation increased PUFA, N3-PUFA, and n6-PUFA in plasma and hepatic fatty acids profiles in lean ducks (P > 0.05) but had on influence on total MUFA and total PUFA in the liver, breast muscle, and plasma in fatty ducks (P > 0.05). In conclusion, genetic selection toward meat production and threonine supplementation increases meat production and PUFA contents, which would influence eating quality, but it is benefit for human health.

Effect of Free-Range and Low-Protein Concentrated Diets on Growth Performance, Carcass Traits, and Meat Composition of Iberian Pig

Simple Summary

It is generally assumed in the Iberian pig sector that substitution of traditional free-range rearing, with acorns and grass, by mixed diets affects intramuscular fat content and fatty-acid composition, among others, causing a decrease in meat quality. As mixed diets are usually formulated with higher protein contents than those supplied by natural resources consumed by Iberian pig fed extensively, we hypothesized that the use of a low-protein diet in the final fattening period of pig could be a suitable strategy to improve meat and dry-cured product quality. However, it is also necessary to evaluate the effect of this strategy on performance and carcass traits of pigs. In this study, we found that Iberian pigs fed on low-protein diets had higher intramuscular fat content and different meat composition compared to pigs fed on concentrates with standard protein levels, which could be a suitable way of improving the Iberian pig meat and dry-cured product quality.

Abstract

The feeding system is one of the main factors influencing the Iberian pig meat quality. This experiment was undertaken to evaluate the influence of feeding diets containing different levels of protein on performance, carcass, and meat quality of Iberian pigs. To that aim, 24 castrated male Retinto Iberian pigs with an average weight of 116 kg were fed under free-range conditions with acorns and grass (FR), and on concentrated diets in confinement with standard (SP) and low protein content (LP). The crude protein content in acorns was lower than that in the grass and SP diet, but similar to that in the LP diet. FR pigs needed more time to achieve slaughter weight than LP and SP pigs. Iberian pigs fed on low-protein diet (FR and LP) had a higher intramuscular fat content in the musculus serratus ventralis than SP pigs. The influence of diet on the fatty-acid composition was reflected more markedly in subcutaneous fat than in muscles. FR pigs showed a higher level of C18:1 n-9 and total polyunsaturated fatty acids and lower total saturated fatty acids in subcutaneous fat than LP and SP. It is concluded that diets with low protein levels do not affect Iberian pig productive traits but change the meat composition, rendering them an interesting strategy to improve the quality of Iberian pig meat and dry-cured products.

Effects of Protein Restriction on Performances and Meat Quality of Cinta Senese Pig Reared in an Organic System

Simple Summary

Fat contained in meat is an important contributor to sensory traits: it increases meat tenderness and flavor. In commercial pigs, increasing meat’s fat was obtained by feeding, until the fattening period, a diet slightly lower in protein respect to their requirements. Local pig breeds, such as Cinta Senese, are known as obese pigs because their great potential to deposit fat, which is mainly stored in backfat deposits. This study was aimed to assess if protein restriction in growing can further increase meat’s fat without alter overall body fatness of obese pigs. The normal feeding management and the restricted one were compared in two groups of Cinta Senese pigs. Results showed that protein restriction during the growing phase affected only few traits. The restricted animal was more able to use the protein in feeding, but few modifications were found in the chemical composition of meat, including the meat’s fat, that remained unchanged. So, obese genotype might be less responsive to this kind of feeding management.

Abstract

In lean genotypes, protein restriction during growing increases intramuscular fat content without affecting the overall carcass fatness. The present study aims to assess the feasibility of applying this feeding management on an obese pig, the Cinta Senese, since obese genotypes are characterized by great lipogenic potential often leading to excessively high backfat deposits. Twenty pigs of average weight 38 kg, were divided in two groups, the first group was fed a protein restricted diet (9% of crude protein), while the second one a normal diet (13.5% of crude protein). During finishing, both groups were fed the same diet (10% of crude protein). Average daily gain, protein conversion index, backfat thickness, carcass weight, and prime cuts were determined. A loin sample joint was dissected in intermuscular fat, bone, subcutaneous fat, longissimus lumborum, and psoas major. On longissimus lumborum, physical and chemical analysis was carried out. The fatty acid profile of longissimus lumborum and loin subcutaneous fat were determined. Data were analyzed by analysis of variance. Protein conversion index resulted lower in the restricted group, while backfat was slightly greater. Meat quality traits were not affected by feeding management. Slightly modifications in subcutaneous outer layer fatty acids profile were observed. The protein restriction during growing did not seem a suitable mode of feeding management for Cinta Senese pigs.

Current feeding strategies to improve pork intramuscular fat content and its nutritional quality

Pork, one of the most consumed meats worldwide, has been facing major challenges regarding its low sensory quality and unhealthy image of fat. This chapter addresses current feeding strategies to ameliorate pork sensory attributes and nutritional quality by increasing intramuscular fat deposition and improving fatty acid composition, respectively. Dietary protein reduction, alone or combined with some components, contributes to satisfy consumer requirements and enhances the competitiveness of the meat industry with higher pork quality and lower production costs. In addition, feeding sources of n-3 polyunsaturated fatty acids to pigs, mainly from marine origin (rich in eicosapentaenoic and docosahexaenoic acids), increases their content in pork, thus improving the health value of its fatty acid profile. In the near future, the inclusion of microalgae and seaweeds in feed represents a promising approach for the maintenance and development of the livestock sector, as an environmental friendly alternative to balance food and feed industries.

Effect of ractopamine on digestible-lysine requirement for finishing barrows under thermoneutral conditions

The purpose of the present study was to determine the digestible-lysine (Lys) requirement in diets supplemented or not with ractopamine (RAC), so as to maximise performance and carcass characteristics for finishing barrows reared at thermoneutral conditions. In total, 128 high-lean commercial hybrid barrows with an initial bodyweight of 78.2 ± 4.3 kg were distributed in a completely randomised block design, in a 4 × 2 factorial arrangement (four Lys concentrations: 0.730%, 0.830%, 0.930% and 1.030% and two RAC inclusions: 0 and 10 mg/kg), with two animals per pen and eight pens per treatment. Lys concentrations tested significantly (P &lt; 0.05) affected digestible-lysine intake, and the absolute (g) and relative (%) lean meat content, regardless of RAC inclusion. When diets were RAC-supplemented, feed conversion rate of animals was improved and, in addition, final bodyweight, daily bodyweight gain, loin eye area, loin eye depth, and absolute (g) and relative (%) carcass lean meat content increased (P &lt; 0.05). RAC inclusion also decreased (P &lt; 0.05) backfat thickness and the colour values a* and b* of finishing pigs. Therefore, on the basis of our results, it can be inferred that the best performance and carcass characteristics for finishing barrows reared at thermoneutral conditions were obtained at 1.030% and 0.730% Lys respectively, corresponding to an estimated daily Lys intake of 34.3 g and 24.2 g, independently of the diet RAC concentration.

Effects of reducing dietary crude protein levels and replacement with crystalline amino acids on growth performance, carcass composition, and fresh pork quality of finishing pigs fed ractopamine hydrochloride

Progeny of GPK-35 females mated to PIC 380 boars were blocked by initial BW, and within the 9 blocks, pens of pigs (3 gilts and 3 barrows/pen) were randomly assigned to dietary treatments where CP of finisher-I, -II, and -III diets was 1) 16.04, 14.55, and 16.23%, respectively (Ctrl); 2) 14.76, 13.48, and 15.27%, respectively (ILE); 3) 14.26, 12.78, and 14.28%, respectively (VAL); or 4) 12.65, 12.38, and 13.32%, respectively (NoSBM). All finisher-III diets included 10 mg/kg of ractopamine hydrochloride (RAC) and a Lys:ME ratio of 2.79 g/Mcal. At slaughter, HCW and Fat-O-Meat'er data were recorded before carcasses were subjected to a rapid chilling process. A subsample of whole hams (2/pen) and whole loins (2/pen) were transported under refrigeration to the University of Arkansas. Hams were dissected with a knife into lean, fat, and bone, and 2.5-cm-thick chops from the semimembranosus (SM) and the LM were used to measure fresh pork quality characteristics. Both ADG and G:F decreased (linear, = 0.05) as CP decreased in finisher-I diets, whereas ADFI was reduced (linear, = 0.01) in response to decreasing CP in finisher-II diets. When RAC was included in the finisher-III diets, ADFI and BW decreased (linear, ≤ 0.03) with decreasing CP, and pigs fed the ILE diet had greater (cubic, < 0.01) G:F than pigs fed the Ctrl and VAL diets. Across the entire finishing period, ADG and ADFI decreased (linear, = 0.01) in response to reductions in dietary CP. Conversely, reducing CP in finisher diets did not ( ≥ 0.13) affect carcass yield, fat depth, LM depth, or calculated fat-free lean yield, and dietary CP content did not ( ≥ 0.09) alter the lean, fat, or bone composition of fresh hams. Moreover, there was no effect of dietary CP on the visual and instrumental color or firmness of the LM ( ≥ 0.06) or SM ( ≥ 0.12). However, there were linear increases in LM marbling scores ( = 0.02) and intramuscular fat content ( = 0.03) as CP was reduced in the finisher diets. Although reducing dietary CP decreased overall ADG and ADFI by approximately 6.1 and 4.9%, respectively, carcass composition was not impacted by dietary CP level. More importantly, reducing dietary CP, although meeting the standard ileal digestible requirements for Lys, Thr, Trp, Met, Ile, and Val with crystalline AA, did not impact pork color or water-holding capacity and actually increased the intramuscular fat content of the LM.

Effects of dietary lysine level on the content and fatty acid composition of intramuscular fat in late-stage finishing pigs

This study was conducted to investigate how dietary lysine level affects the intramuscular fat (IMF) content and fatty acid (FA) composition in late-stage finishing pigs. Nine crossbred barrows [94.4 ± 6.7 kg body weight (BW)] were randomly allotted to three treatment groups (n = 3). Three corn- and soybean-meal-based diets were formulated to meet the National Research Council (2012) requirements for various nutrients except for lysine, whose concentrations were 0.43%, 0.71%, and 0.98% (as-fed basis) for Diets 1 (lysine-deficient), 2 (lysine-adequate), and 3 (lysine-excess), respectively. After 5 wk of ad libitum access to diets, pigs were harvested and longissimus dorsi samples were collected. The IMF content and FA composition of the samples were analyzed by gas chromatography. Results showed that the IMF content of the muscle was increased linearly (P < 0.05) with decreasing dietary lysine level from 0.98% to 0.43%. Dietary lysine level altered the composition of FA, especially the unsaturated FA, in the muscle. Particularly, the percentages of C18:1 n-9 and total monounsaturated FA were higher, whereas the percentages of C18:2 n-6 and total polyunsaturated FA were lower, in the muscle of the pigs fed Diet 1. Collectively, dietary lysine deficiency increased the proportion of monounsaturated FA and decreased the proportion of polyunsaturated FA, which may benefit pork palatability.

Dietary Supplementation with Pioglitazone Hydrochloride and Chromium Methionine Improves Growth Performance, Meat Quality, and Antioxidant Ability in Finishing Pigs

This work was designed to investigate the synergistic effects of pioglitazone hydrochloride (PGZ) and chromium methionine (CrMet) on meat quality, muscle fatty acid profile, and antioxidant ability of pigs. Pigs in four groups were fed a basic diet or basic diet supplemented with 15 mg/kg of PGZ, 200 μg/kg of CrMet, or 15 mg/kg of PGZ + 200 μg/kg of CrMet. In comparison to the control group, the average daily feed intake, feed/gain ratio, and serum high-density lipoprotein level decreased in the PGZ + CrMet group. Dietary PGZ + CrMet supplementation increased carcass dressing percentage, intramuscular fat, and marbling score. The percentages of C18:1ω-9c, C18:2ω-6c, C18:3ω-3, and polyunsaturated fatty acid (PUFA) in the longissimus thoracis muscle were increased in the PGZ + CrMet group. Greater superoxide dismutase and glutathione peroxidase activities were observed in the PGZ + CrMet group compared to the control group. Collectively, these findings suggested that feed with PGZ and CrMet improved the growth performance and meat quality, especially for PUFA proportions and antioxidant ability.

Similar effects of lysine deficiency in muscle biochemical characteristics of fatty and lean piglets

The main objective of this work was to investigate the effects of feeding Lys-deficient diets on muscle biochemical characteristics, particularly intramuscular fat concentration and fatty acid profile, in a fatty (Iberian) and a conventional pig genotype (Landrace × Large White [LDW]) maintained in identical experimental conditions. Performance and plasma metabolite changes were also monitored. Twenty-eight barrows of 10 kg initial BW, 14 of Iberian and 14 of LDW breed, were randomly assigned to each of 2 experimental diets in a 2 × 2 factorial arrangement (2 breeds × 2 diets). Seven pigs were allocated to each treatment combination. Diets (isonitrogenous and isoenergetic; 200 g CP/kg DM and 14.7 MJ ME) based on barley, corn, corn gluten meal, and soybean meal, with identical composition, except for their Lys content (10.9 g/kg for the diet adequate in Lys and 5.2 g/kg for the diet deficient in Lys), were assayed. Pigs were housed in individual 2 m pens and fed at 85% of ad libitum intake of the Iberian genotype, of greater intake capacity. Daily feed allowance was based on BW individually measured each week. At 25 kg BW, pigs were slaughtered by exsanguination after electrical stunning. Blood samples were taken and longissimus dorsi and biceps femoris muscles were rapidly dissected and stored frozen prior to analysis. Performance was reduced in both pig breeds when fed Lys-deficient diets, particularly in LDW pigs (breed × diet interaction, < 0.05). Intramuscular fat content increased in longissimus dorsi of Iberian ( < 0.05) and in biceps femoris of both pig genotypes ( < 0.01) when fed Lys-deficient diets. Oleic acid increased ( < 0.05) and PUFA acid decreased ( < 0.01) in longissiumus dorsi and biceps femoris of pigs of both genotypes fed Lys-deficient diets. The proportion of oxidative fibers ( < 0.001) and free carnitine content ( < 0.05) increased in longissimus dorsi of both pigs types fed Lys-deficient diets. Plasma creatinine was greater in LDW pigs compared with Iberian pigs ( < 0.01). Urea and total cholesterol increased in pigs consuming Lys-deficient diets ( < 0.01). The plasma free carnitine concentration was higher in Iberian pigs than in LDW pigs ( < 0.059). No changes in plasma carnitine status due to dietary Lys supply were detected. Feeding Lys-deficient diets could be a suitable strategy for increasing intramuscular fat content in fatty and lean pigs.

Lower Expression of SLC27A1 Enhances Intramuscular Fat Deposition in Chicken via Down-Regulated Fatty Acid Oxidation Mediated by CPT1A

Intramuscular fat (IMF) is recognized as the predominant factor affecting meat quality due to its positive correlation with tenderness, juiciness, and flavor. Chicken IMF deposition depends on the balance among lipid synthesis, transport, uptake, and subsequent metabolism, involving a lot of genes and pathways, however, its precise molecular mechanisms remain poorly understood. In the present study, the breast muscle tissue of female Wenchang chickens (WC) (higher IMF content, 1.24 in D120 and 1.62 in D180) and female White Recessive Rock chickens (WRR; lower IMF content, 0.53 in D120 and 0.90 in D180) were subjected to RNA-sequencing (RNA-seq) analysis. Results showed that many genes related to lipid catabolism, such as SLC27A1, LPL, ABCA1, and CPT1A were down-regulated in WC chickens, and these genes were involved in the PPAR signaling pathway and formed an IPA® network related to lipid metabolism. Furthermore, SLC27A1 was more down-regulated in WRR.D180.B than in WRR.D120.B. Decreased cellular triglyceride (TG) and up-regulated CPT1A were observed in the SLC27A1 overexpression QM-7 cells, and increased cellular triglyceride (TG) and down-regulated CPT1A were observed in the SLC27A1 knockdown QM-7 cells. These results suggest that lower lipid catabolism exists in WC chickens but not in WRR chickens, and lower expression of SLC27A1 facilitate IMF deposition in chicken via down-regulated fatty acid oxidation mediated by CPT1A. These findings indicate that reduced lipid catabolism, rather than increased lipid anabolism, contributes to chicken IMF deposition.

Arginine supplementation modulates pig plasma lipids, but not hepatic fatty acids, depending on dietary protein level with or without leucine

Background

In the present study, the effect of arginine and leucine supplementation, and dietary protein level, were investigated in commercial crossbred pigs to clarify their individual or combined impact on plasma metabolites, hepatic fatty acid composition and mRNA levels of lipid sensitive factors. The experiment was conducted on fifty-four entire male pigs (Duroc × Pietrain × Large White × Landrace crossbred) from 59 to 92 kg of live weight. Each pig was randomly assigned to one of six experimental treatments (n = 9). The treatments followed a 2 × 3 factorial arrangement, providing two levels of arginine supplementation (0 vs. 1%) and three levels of basal diet (normal protein diet, NPD; reduced protein diet, RPD; reduced protein diet with 2% of leucine, RPDL).

Results

Significant interactions between arginine supplementation and protein level were observed across plasma lipids. While dietary arginine increased total lipids, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol and triacylglycerols in NPD, the inverse effect was observed in RPD. Overall, dietary treatments had a minor impact on hepatic fatty acid composition. RPD increased 18:1c9 fatty acid while the combination of leucine and RPD reduced 18:0 fatty acid. Arginine supplementation increased the gene expression of FABP1, which contributes for triacylglycerols synthesis without affecting hepatic fatty acids content. RPD, with or without leucine addition, upregulated the lipogenic gene CEBPA but downregulated the fat oxidation gene LPIN1.

Conclusions

Arginine supplementation was responsible for a modulated effect on plasma lipids, which is dependent on dietary protein level. It consistently increased lipaemia in NPD, while reducing the correspondent metabolites in RPD. In contrast, arginine had no major impact, neither on hepatic fatty acids content nor on fatty acid composition. Likewise, leucine supplementation of RPD, regardless the presence of arginine, promoted no changes on total fatty acids in the liver. Ultimately, arginine, leucine and dietary protein reduction seem to be unrelated with fatty liver development.

Enhancement of porcine intramuscular fat content by overexpression of the cytosolic form of phosphoenolpyruvate carboxykinase in skeletal muscle

Intramuscular fat (IMF) content has been generally recognized as a desirable trait in pork meat because of its positive effect on eating quality. An effective approach to enhance IMF content in pork is the generation of transgenic pigs. In this study, we used somatic cell nuclear transfer (SCNT) to generate cloned pigs exhibiting ectopic expression of phosphoenolpyruvate carboxykinase (PEPCK-C) driven by an α-skeletal-actin gene promoter, which was specifically expressed in skeletal muscle. Using qRT-PCR and Western blot analysis, we demonstrated that PEPCK-C was functionally expressed and had a significant effect on total fatty acid content in the skeletal muscle of the transgenic pigs, while the n-6/n-3 polyunsaturated fatty acid (PUFA) ratio showed no difference between transgenic and control pigs. Thus, genetically engineered PEPCK-C^mus pigs may be an effective solution for the production of IMF-enriched pork.

Effect of dietary kapok oil supplementation on growth performance, carcass traits, meat quality and sensory traits of pork in finishing-pigs

Kapok seed and oil from the tropical zone are widely used as pig feed to harden porcine fat in Japan. This study evaluated the effect of dietary kapok oil supplementation on pork quality and sensory traits. Five Duroc pigs each were assigned to an experimental group supplemented with kapok oil and a control group. Dietary kapok oil supplementation had no effect on growth performance and intramuscular fat content in the Longissimus dorsi muscle (LM). Supplemental kapok oil increased saturated fatty acid contents in subcutaneous and intramuscular fat and decreased monounsaturated fatty acid levels (P < 0.05). Off-flavor detection by a trained panel was higher in the experimental than the control group (P < 0.05), but tenderness, juiciness, texture and flavor intensity of LM chops were similar in both groups. The overall palatability of pork as judged by a consumer panel decreased with kapok oil supplementation (P < 0.01). These results indicate that while growth performance, intramuscular fat contents and carcass characteristics were unchanged, while dietary kapok oil supplementation makes firm fat to prevent inferior soft fat in pork, it can lower the palatability of pork due to a decrease in monounsaturated fatty acids.

Higher membrane fluidity mediates the increased subcutaneous fatty acid content in pigs fed reduced protein diets

The production of pork with moderate amounts of intramuscular fat (IMF) without an increase in subcutaneous fat is highly desirable for the meat industry. Several studies indicate that dietary protein reduction during the growing-finishing period of pigs enhances IMF content, but its consequence on carcass fat deposition is still contradictory. In this study, we hypothesized that the effects of reduced protein diets (RPD), corrected or not with the limiting amino acid lysine, on subcutaneous fat deposition from pigs with distinct genotypes are mediated by adipose membranes biophysical properties. In total, 36 crossbred (Large White×Landrace×Pietrain - a lean genotype) and purebred (Alentejana breed - a fatty genotype) male pigs were randomly assigned to the control group, the RPD group or the reduced protein diet equilibrated for lysine (RPDL) group, allowing a 2×3 factorial arrangement (n=6). Backfat thickness and total fatty acid content were higher in Alentejana relative to crossbred pigs. Although dietary treatments did not change backfat thickness, RPD and RPDL increased total fatty acids content of subcutaneous fat. In order to understand this effect, adipose tissue membranes isolated from pig's subcutaneous fat were assayed for glycerol permeability and fluidity, using 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-(trimethylamino)-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) probes. The glycerol transport across adipose membranes was not mediated by aquaglyceroporins and remained unchanged across dietary groups. Regardless of lysine correction, RPD increased membrane fluidity at the hydrocarbon region (lower DPH fluorescence anisotropy) in both genotypes of pigs. This result was associated with a lower ratio between oleic acid and linoleic acid on membrane's fatty acid composition. Adipose membrane's cholesterol content was independent from genotype and diet. Taken together, the present study shows that dietary protein reduction is successful in maintaining backfat thickness, although a negative side effect was observed on total fatty acids in subcutaneous fat, which may be due to changes in the fluidity of adipose membranes.

Beef palatability and its relationship with protein degradation and muscle fibre type profile in longissimus thoracis in Alentejana breed from divergent growth pathways

The traditional beef production in the South of Portugal is based on a discontinuous growth (DG) system that requires lower external inputs and could enhance meat quality and financial returns to cattle producers. This system allows farmers to take advantage of the bull's compensatory growth when the pasture is abundant and finishes the cattle on concentrates for 2 to 3 months before slaughter. The fast gain rate before slaughter could be a valuable strategy to improve tenderness and to reduce its inconsistency in beef production. Therefore, the aim of this study was to evaluate the effects of production system (continuous growth (CG) v. DG) on longissimus thoracis muscle properties from Alentejana bulls. In total, 40 Alentejana male calves were allocated to two distinct feeding regimes: in the CG system, animals were fed concentrate plus hay and slaughtered at 18 months of age, whereas in the DG system, animals were fed on hay until 15 months of age and then fed the same diet provided to the CG group until 24 months of age. The DG system had a positive impact on meat tenderness (P<0.001) and global acceptability (P<0.001). DG bulls had greater fibre cross-sectional area (CSA) of glycolytic fibres (P<0.05) and relative area of the muscle (RA) occupied by type IIX fibres (P<0.01) and greater levels of α-actinin (P<0.05) and myosin light chain 2 (P<0.01) proteins, and pH24h (P<0.01) than CG bulls. The latter had greater CSA of type I (P<0.05) and type IIA (P<0.01) and greater RA of type IIA (P<0.05) and oxidative (P<0.05) than CG bulls. The compensatory growth production system had a positive impact on meat tenderness and global acceptability, overcoming the negative effects of slaughter of the bulls at a later age. The DG beef system could be a worthwhile strategy of beef production in Mediterranean areas due to the low-quality pasture in summer.

Mechanisms of protein balance in skeletal muscle

Increased global demand for adequate protein nutrition against a backdrop of climate change and concern for animal agriculture sustainability necessitates new and more efficient approaches to livestock growth and production. Anabolic growth is achieved when rates of new synthesis exceed turnover, producing a positive net protein balance. Conversely, deterioration or atrophy of lean mass is a consequence of a net negative protein balance. During early life and periods of growth, muscle mass is driven by increases in protein synthesis at the level of mRNA translation. Throughout life, muscle mass is further influenced by degradative processes such as autophagy and the ubiquitin proteasome pathway. Multiple signal transduction networks guide and coordinate these processes alongside quality control mechanisms to maintain protein homeostasis (proteostasis). Genetics, hormones, and environmental stimuli each influence proteostasis control, altering capacity and/or efficiency of muscle growth. An overview of recent findings and current methods to assess muscle protein balance and proteostasis is presented. Current efforts to identify novel control points have the potential through selective breeding design or development of hormetic strategies to better promote growth and health span during environmental stress.

Restriction of dietary protein does not promote hepatic lipogenesis in lean or fatty pigs

The influence of genotype (lean v. fatty) and dietary protein level (normal v. reduced) on plasma metabolites, hepatic fatty acid composition and mRNA levels of lipid-sensitive factors is reported for the first time, using the pig as an experimental model. The experiment was conducted on forty entire male pigs (twenty lean pigs of Large White×Landrace×Pietrain cross-breed and twenty fatty pigs of Alentejana purebreed) from 60 to 93 kg of live weight. Each pig genotype was divided into two subgroups, which were fed the following diets: a normal protein diet (NPD) equilibrated for lysine (17·5 % crude protein and 0·7 % lysine) and a reduced protein diet (RPD) not equilibrated for lysine (13·1 % crude protein and 0·4 % lysine). The majority of plasma metabolites were affected by genotype, with lean pigs having higher contents of lipids, whereas fatty pigs presented higher insulin, leptin and urea levels. RPD increased plasma TAG, free fatty acids and VLDL-cholesterol compared with NPD. Hepatic total lipids were higher in fatty pigs than in the lean genotype. RPD affected hepatic fatty acid composition but had a slight influence on gene expression levels in the liver. Sterol regulatory element-binding factor 1 was down-regulated by RPD, and fatty acid desaturase 1 (FADS1) and fatty acid binding protein 4 (FABP4) were affected by the interaction between genotype and diet. In pigs fed RPD, FADS1 was up-regulated in the lean genotype, whereas FABP4 increased in the fatty genotype. Although there is a genotype-specific effect of dietary protein restriction on hepatic lipid metabolism, lipogenesis is not promoted in the liver of lean or fatty pigs.

Increased intramuscular fat induced by reduced dietary protein in finishing pigs: effects on the longissimus lumborum muscle proteome

Reduced protein diets affects the amounts of proteins related to fibre type and structure and energy.