Genetics of Omega-3 Long-Chain Polyunsaturated Fatty Acid Metabolism and Meat Eating Quality in Tattykeel Australian White Lambs

Muscle biopsy long-chain omega-3 polyunsaturated fatty acid compositions, IMF and FMP in Australian pasture-based Bowen Genetics Forest Pastoral Angus, Hereford, and Wagyu Beef Cattle

BACKGROUND

We investigated breed and gender variations in the compositions of long-chain (≥ C20) omega-3 polyunsaturated fatty acids (LC omega-3 PUFA), fat melting point (FMP) and intramuscular fat (IMF) contents in biopsy samples of the M. longissimus dorsi muscle of grazing beef cattle. The hypothesis that biopsy compositions of health-beneficial LC omega-3 PUFA, FMP and IMF in a pasture-based production system will vary with breed, was tested. Muscle biopsies were taken from 127 yearling pasture-based Angus, Hereford, and Wagyu heifers and young bulls exclusive to the Australian Bowen Genetics Forest Pastoral breeding stud averaging 12 ± 2.43 months of age and under the same management routine.

RESULTS

Breed had a significant influence on IMF, FMP, and the compositions of oleic acid, α-linolenic acid (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA), docosapentaenoic (DPA), and total EPA + DHA + DPA in the M. longissimus dorsi muscle biopsies (P ≤ 0.03). The Wagyu breed had the highest (11.1%) and Hereford the lowest (5.9%) IMF (P = 0.03). The reverse trend was observed in FMP values where the Hereford breed had the highest (55 °C), Angus intermediate (46.5 °C), and Wagyu the lowest (33 °C) FMP. The Wagyu and Angus breeds had similar oleic fatty acid (18:1n-9) content, while the Hereford breed had the lowest (P < 0.01). The highest ALA, DPA, total EPA + DHA, total EPA + DHA + DPA and total ALA + EPA + DHA + DPA contents were detected in the Wagyu breed (P ≤ 0.03). The Hereford had similar EPA and DPA contents to the Angus (P ≥ 0.46). Total EPA + DHA + DPA contents in Wagyu, Angus, and Hereford were 28.8, 21.5, and 22.1 mg/100g tissue (P = 0.01), respectively. Sex was an important source of variation that influenced LC omega-3 PUFA composition, FMP and IMF, where yearling heifers had higher IMF (11.9% vs 5.3%), lower FMP (33°C vs 37°C), and higher LC omega-3 PUFA than bulls.

CONCLUSION

All the results taken together indicate that the Wagyu breed at 28.8 mg/100g tissue, was the closest to meeting the Australia and New Zealand recommended source level threshold of 30 mg/100g tissue of health-beneficial ≥ C20 omega-3 FA content. Since gender was a significant determinant of LC omega-3 PUFA composition, IMF content and FMP, it should be factored into enhancement strategies of healthy meat eating quality traits in grazing cattle. These findings also suggest that the Bowen Genetics Forest Pastoral beef cattle studs are important sources of LC omega-3 PUFA that can be used to cover the deficit in these health claimable fatty acids in Western diets.

Chestnut tannin extract modulates growth performance and fatty acid composition in finishing Tan lambs by regulating blood antioxidant capacity, rumen fermentation, and biohydrogenation

Tannins as plant extracts have emerged as promising and potential alternatives for antibiotics in modern livestock cultivation systems. This study investigates the effect of dietary chestnut tannin extract (CTE) in finishing Tan lambs. Twenty-seven male Tan lambs were randomly divided into three groups: (1) control group (CON; basal diet); (2) low-dose CTE group (LCTE; basal diet + 2 g/kg CTE, dry matter [DM] basis); (3) high-dose CTE group (HCTE; basal diet + 4 g/kg CTE, DM basis). The HCTE group exhibited markedly higher average daily gain (ADG) and DM intake than CON (P < 0.01). The ruminal total volatile fatty acid concentration increased linearly with increasing CTE supplementation (P < 0.01), while the opposite trend was observed for butyrate molar proportion (P < 0.01). Upon increasing CTE dosage, plasma glucose, high-density lipoprotein cholesterol, glutathione peroxidase, and superoxide dismutase content increased linearly (P < 0.05), whereas low-density lipoprotein cholesterol and urea nitrogen decreased linearly or quadratically (P < 0.05), respectively. A linear increase was also observed in ruminal t6 C18:1 and t9, c12 C18:2 proportions (P < 0.01), and plasma C18:2n-6 and n-6 polyunsaturated fatty acids proportions with increased CTE supplementation (P < 0.01). In the longissimus dorsi muscle, the atherogenic index decreased linearly (P < 0.05), while c11 C18:1 and C20:5n-3 increased linearly (P < 0.05). Moreover, c9, t11 conjugated linoleic acids proportion increased in subcutaneous fat with CTE supplementation (P < 0.01). In conclusion, Dietary CTE enhances the ADG of finishing Tan lambs in a dose-dependent manner, modulates plasma metabolites and antioxidant capacity, and improves rumen fermentation and body fatty acid composition. These results provide a reference for the rational application of CTE in ruminant production.

Expression profile of FASN gene and association of its polymorphisms with intramuscular fat content in Hu sheep

The content of intramuscular fat (IMF) is one of the most important factors that has a large impact on meat quality, and it is an effective way to improve IMF according to marker-assisted selection (MAS). Fatty-acid synthase (FASN) is a key gene in meat lipid deposition and fatty acid composition. Thus, this study was conducted to investigate the expression profile of FASN in mRNA and protein levels using real-time quantitative PCR (RT-qPCR) and western-blot methods. In addition, single nucleotide polymorphisms (SNPs) within FASN in 921 Hu rams with IMF content records were investigated using DNA-pooling sequencing and improved multiple ligase detection reaction (iMLDR) methods. Consequently, the highest mRNA expression level of FASN was observed in the perinephric fat, and the lowest in the liver among the 11 tissues analyzed, while no significant difference was found in mRNA and protein expression levels in longissimus dorsi among individuals with different IMF contents. A total of 10 putative SNPs were identified within FASN, and 9 of them can be genotyped by iMLDR method. Notably, two SNPs were significantly associated with IMF content, including NC_040262.1: g.5157 A > G in intron 5 (p = 0.046) and NC_040262.1: g.9413 T > C in intron 16 (p = 0.041), which supply molecular markers for improving meat quality in sheep breeding.

Variation in Acetyl-CoA Carboxylase Beta Gene and Its Effect on Carcass and Meat Traits in Gannan Yaks

Acetyl-CoA carboxylase beta (ACACB) is a functional candidate gene that impacts fat deposition. In the present study, we sequenced exon 37-intron 37, exon 46-intron 46, and intron 47 of yak ACACB using hybrid pool sequencing to search for variants and genotyped the gene in 593 Gannan yaks via Kompetitive allele-specific polymerase chain (KASP) reaction to determine the effect of ACACB variants on carcass and meat quality traits. Seven single nucleotide polymorphisms were detected in three regions. Eight effective haplotypes and ten diplotypes were constructed. Among them, a missense variation g.50421 A > G was identified in exon 37 of ACACB, resulting in an amino acid shift from serine to glycine. Correlation analysis revealed that this variation was associated with the cooking loss rate and yak carcass weight (p = 0.024 and 0.012, respectively). The presence of haplotypes H5 and H6 decreased Warner-Bratzler shear force (p = 0.049 and 0.006, respectively), whereas that of haplotypes H3 and H4 increased cooking loss rate and eye muscle area (p = 0.004 and 0.034, respectively). Moreover, the presence of haplotype H8 decreased the drip loss rate (p = 0.019). The presence of one and two copies of haplotypes H1 and H8 decreased the drip loss rate (p = 0.028 and 0.004, respectively). However, haplotype H1 did not decrease hot carcass weight (p = 0.011), whereas H3 increased the cooking loss rate (p = 0.007). The presence of one and two copies of haplotype H6 decreased Warner-Bratzler shear force (p = 0.014). The findings of the present study suggest that genetic variations in ACACB can be a preferable biomarker for improving yak meat quality.

Evaluation of the Longissimus Thoracis et Lumborum Muscle Quality of Chaka and Tibetan Sheep and the Analysis of Possible Mechanisms Regulating Meat Quality

This study aimed to comprehensively evaluate the characteristics in the longissimus thoracis et lumborum (LTL) muscle of Chaka (CK) sheep and Tibetan (TB) sheep, and transcriptomics-metabolomics association analysis was used to find the possible genes, differential metabolites, and significant differential metabolic pathways that lead to meat quality differences. Based on the researched results, the nutritional quality of meat, including the contents of ether extract (11.95% vs. 10.56%), unsaturated fatty acid (51.20% vs. 47.69%), and polyunsaturated fatty acid (5.71% vs. 3.97%), were better in TB sheep than in CK sheep, while the CK sheep has better muscle fiber characteristics, such as the total number (62 vs. 45) and muscle fiber density (1426.54 mm2 vs. 1158.77 mm2) and flavor. Omics research has shown that the key differential metabolites and metabolic pathways were dominated by amino acid metabolism, particularly the glutathione metabolism, taurine and hypotaurine metabolism, and lipid metabolism-related pathways, such as glycerophospholipid metabolism and the sphingolipid signaling pathway. The intermediate metabolite sn-Glycerol 3-phosphoethanolamine played a key role in determining sheep meat quality, which was regulated by GPAT2, PLPP2, AGPAT1, PNPLA2, and GPAT4 and correlated with meat color, texture, and flavor. Overall, these results will provide effective information and more evidence to support further exploration of valuable biomarkers of meat quality.

Effects of Sheep Sires on Muscle Fiber Characteristics, Fatty Acid Composition and Volatile Flavor Compounds in F(1) Crossbred Lambs

Crossbreeding significantly improves meat production performance in sheep; however, whether hybridization changes the meat quality characteristics of lambs is uncertain. We analyzed the effects of three different hybrid sires on muscle fiber characteristics (MFCs), fatty acid composition (FAC), and volatile flavor compounds (VFCs) in lambs under identical feeding conditions. Compared with those of purebred lambs, the muscle fiber diameter and cross-sectional areas of the crossbred lambs were significantly decreased (p < 0.05), and the collagen fiber content was significantly increased (p < 0.05). The numbers and area ratios of the fast and slow muscle fibers did not significantly differ between the purebred and crossbred lambs, but the expressions of four MyHC gene types differed significantly (p < 0.05). Twenty-three fatty acids were identified in both the purebred and crossbred lambs, of which thirteen were differentially expressed (p < 0.05). Saturated fatty acid (SFA) contents in the crossbred lambs were significantly increased (p < 0.05), whereas the monounsaturated fatty acid content was significantly decreased (p < 0.05). Polyunsaturated fatty acid/SFA and n-6/n-3 ratios were significantly lower in the crossbred lambs than in the purebred lambs (p < 0.05). Twenty-five VFCs were identified among the three hybrids, and aldehydes were the main VFCs. Eleven VFCs were differentially expressed in the crossbred lambs (p < 0.05). Hybrid sires affected the MFCs, FAC, and VFCs of the F1 lambs, thus providing a reference for high-quality mutton production.

Lipidomics and Transcriptome Reveal the Effects of Feeding Systems on Fatty Acids in Yak’s Meat

The differences of fatty acids in yak’s meat under graze feeding (GF) and stall feeding (SF) regimes and the regulation mechanism of the feeding system on the fatty acids content in yak ’s meat was explored in this study. First, the fatty acids in yak’s longissimus dorsi (LD) muscle were detected by gas liquid chromatography (GLC). Compared with GF yaks, the absolute content of ΣSFAs, ΣMUFAs, ΣUFAs, ΣPUFAs and Σn-6PUFAs in SF yak’s LD were higher, whereas Σn-3PUFAs was lower; the relative content of ΣMUFAs, ΣPUFAs, Σn-3PUFAs and ΣUFAs in SF yak’s LD were lower, whereas ΣSFAs was higher. The GF yak’s meat is healthier for consumers. Further, the transcriptomic and lipidomics profiles in yak’s LD were detected by mRNA-Sequencing (mRNA-Seq) and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS), respectively. The integrated transcriptomic and lipidomics analysis showed the differences in fatty acids were caused by the metabolism of fatty acids, amino acids, carbohydrates and phospholipids, and were mainly regulated by the FASN, FABP3, PLIN1, SLC16A13, FASD6 and SCD genes in the PPAR signaling pathway. Moreover, the SCD gene was the candidate gene for the high content of ΣMUFA, and FADS6 was the candidate gene for the high content of Σn-3PUFAs and the healthier ratio of Σn-6/Σn-3PUFAs in yak meat. This study provides a guidance to consumers in the choice of yak’s meat, and also established a theoretical basis for improving yak’s meat quality.

Impact of dietary Lactobacillus supplementation on intramuscular fat deposition and meat quality of Sunit sheep

To investigate the impacts of dietary Lactobacillus supplementation on meat quality such as edible quality and nutritional value of Sunit sheep, a 90-day feeding experiment (Lactobacillus dietary group, R group; non-Lactobacillus dietary group, C group) using twelve 3-month-old Sunit sheep was conducted. The deposition of intramuscular fat (IMF) was increased (p < .05) while the share force and cooking loss were decreased (p < .05) in the R group compared with the C group. The proportions of seven kinds of fatty acids (FAs) have changed significantly (p < .05), especially with higher functional FAs and lower trans-FA in the R group. Metabonomics analysis showed that the metabolites and pathway-related lipid syntheses, such as carnitine cycle, tricarboxylic acid cycle, and glycerophosphocholine metabolic pathway, have significantly changed in the R group. The Lactobacillus dietary supplements impacted the variation of IMF deposition and FAs composition by altering the lipid metabolism pathways of Sunit sheep and then changed the edible quality and nutritional value. PRACTICAL APPLICATIONS: It is well known that the intramuscular fat (IMF) and fatty acids composition in livestock is positively correlated with various aspects of meat quality such as edible quality and nutritional value, which are related to consumer preference. The present study analyzed the effects of Lactobacillus supplement on the intramuscular fat deposition and meat quality of Sunit sheep, which resulted in the increase of IMF, and the differences of fatty acids composition, especially the functional fatty acids. It was explored the mechanism of Lactobacillus affect the variation of lipid metabolism pathways and key metabolites in sheep, which suggested that altering the feeding regimen could improve the meat quality of agri-animals.

Integrated analysis of expression profiles with meat quality traits in cattle

MicroRNAs (miRNAs) play a vital role in improving meat quality by binding to messenger RNAs (mRNAs). We performed an integrated analysis of miRNA and mRNA expression profiling between bulls and steers based on the differences in meat quality traits. Fat and fatty acids are the major phenotypic indices of meat quality traits to estimate between-group variance. In the present study, 90 differentially expressed mRNAs (DEGs) and 18 differentially expressed miRNAs (DEMs) were identified. Eighty-three potential DEG targets and 18 DEMs were used to structure a negative interaction network, and 75 matching target genes were shown in this network. Twenty-six target genes were designated as intersection genes, screened from 18 DEMs, and overlapped with the DEGs. Seventeen of these genes enriched to 19 terms involved in lipid metabolism. Subsequently, 13 DEGs and nine DEMs were validated using quantitative real-time PCR, and seven critical genes were selected to explore the influence of fat and fatty acids through hub genes and predict functional association. A dual-luciferase reporter and Western blot assays confirmed a predicted miRNA target (bta-miR-409a and PLIN5). These findings provide substantial evidence for molecular genetic controls and interaction among genes in cattle.

Genetics and nutrition impacts on herd productivity in the Northern Australian beef cattle production cycle

Genetics and nutrition drive herd productivity due to significant impacts on all components of the beef cattle production cycle. In northern Australia, the beef production system is largely extensive and relies heavily on tropical cattle grazing low quality, phosphorus-deficient pastures with seasonal variations in nutritive value. The existing feedlots are predominantly grain-based; providing high-energy rations, faster turn-off and finishing of backgrounded cattle to meet market specifications. This review focusses on the beef cattle production cycle components of maternal nutrition, foetal development, bull fertility, post-natal to weaning, backgrounding, feedlotting, rumen microbes and carcass quality as influenced by genetics and nutrition. This student-driven review identified the following knowledge gaps in the published literature on northern Australian beef cattle production cycle: 1. Long-term benefits and effects of maternal supplementation to alter foetal enzymes on the performance and productivity of beef cattle; 2. Exogenous fibrolytic enzymes to increase nutrient availability from the cell wall and better utilisation of fibrous and phosphorus deficient pasture feedbase during backgrounding; 3. Supplementation with novel encapsulated calcium butyrate and probiotics to stimulate the early development of rumen papillae and enhance early weaning of calves; 4. The use of single nucleotide polymorphisms as genetic markers for the early selection of tropical beef cattle for carcass and meat eating quality traits prior to feedlotting; The review concludes by recommending future research in whole genome sequencing to target specific genes associated with meat quality characteristics in order to explore the development of breeds with superior genes more suited to the North Australian beef industry. Further research into diverse nutritional strategies of phosphorus supplementation and fortifying tropically adapted grasses with protein-rich legumes and forages for backgrounding and supplementing lot-fed beef cattle with omega-3 oil of plant origin will ensure sustainable production of beef with a healthy composition, tenderness, taste and eating quality.

Effects of different dietary fat levels and sources on diet digestibility, fattening performance and meat quality of Holstein young bulls when substituted for dietary barley grain

The aim of the present study was to investigate the effects of substituting dietary barley grain by different sources and levels of fat on performance and meat quality of Holstein young bulls. Twenty-eight Holstein male calves, 274 ± 32 kg initial body weight, were used in a completely randomised design with a 2 × 2 factorial treatment arrangement for 100 d (with 10 d of adaptation). Seven animals were randomly allocated per treatment. Four dietary treatments were tested, which included: (1) diet supplemented with saturated fat (Energizer® RP10) at low level (diet with high barley and starch content), (2) diet supplemented with saturated fat at high level (diet with low barley and starch content), (3) diet supplemented with unsaturated fat (Persiafat) at low level (diet with high barley and starch content) and (4) diet supplemented with unsaturated fat at high level (diet with low barley and starch content). The dry matter intake, average daily gain, feed conversion ratio and carcass traits were not affected by supplemental fat sources and levels. Total tract digestibility of acid detergent fibre was improved after inclusion of both rumen-protected fat sources while other nutrient digestibilities were not affected by the fat sources or levels. In conclusion, partial replacing of dietary starch with fat supplements has not negative effects on calves' performance and digestibility of neutral detergent fibre.

Dietary Coleus amboinicus Lour. decreases ruminal methanogenesis and biohydrogenation, and improves meat quality and fatty acid composition in longissimus thoracis muscle of lambs

Background

Methane production and fatty acids (FA) biohydrogenation in the rumen are two main constraints in ruminant production causing environmental burden and reducing food product quality. Rumen functions can be modulated by the biologically active compounds (BACs) of plant origins as shown in several studies e.g. reduction in methane emission, modulation of FA composition with positive impact on the ruminant products. Coleus amboinicus Lour. (CAL) contains high concentration of polyphenols that may potentially reduce methane production and modulate ruminal biohydrogenation of unsaturated FA.

This study aimed to investigate the effect of BAC of Coleus amboinicus Lour. (CAL) fed to growing lambs on ruminal methane production, biohydrogenation of unsaturated FA and meat characteristics. In this study, the in vitro experiment aiming at determining the most effective CAL dose for in vivo experiments was followed by two in vivo experiments in rumen-cannulated rams and growing lambs. Experiment 1 (RUSITEC) comprised of control and three experimental diets differing in CAL content (10%, 15%, and 20% of the total diet). The two in vivo experiments were conducted on six growing, rumen-cannulated lambs (Exp. 2) and 16 growing lambs (Exp. 3). Animals were assigned into the control (CON) and experimental (20% of CAL) groups. Several parameters were examined in vitro (pH, ammonia and VFA concentrations, protozoa, methanogens and select bacteria populations) and in vivo (methane production, digestibility, ruminal microorganism populations, meat quality, fatty acids profiles in rumen fluid and meat, transcript expression of 5 genes in meat).

Results

CAL lowered in vitro methane production by 51%. In the in vivo Exp. 3, CAL decreased methane production by 20% compared with the CON group, which corresponded to reduction of total methanogen counts by up to 28% in all experiments, notably Methanobacteriales. In Exp. 3, CAL increased or tended to increase populations of some rumen bacteria (Ruminococcus albus, Megasphaera elsdenii, Butyrivibrio proteoclasticus, and Butyrivibrio fibrisolvens). Dietary CAL suppressed the Holotricha population, but increased or tended to increase Entodiniomorpha population in vivo. An increase in the polyunsaturated fatty acid (PUFA) proportion in the rumen of lambs was noted in response to the CAL diet, which was mainly attributable to the increase in C18:3 cis-9 cis-12 cis-15 (LNA) proportion. CAL reduced the mRNA expression of four out of five genes investigated in meat (fatty acid synthase, stearoyl-CoA desaturase, lipoprotein lipase, and fatty acid desaturase 1).

Conclusions

Summarizing, polyphenols of CAL origin (20% in diet) mitigated ruminal methane production by inhibiting the methanogen communities. CAL supplementation also improved ruminal environment by modulating ruminal bacteria involved in fermentation and biohydrogenation of FA. Besides, CAL elevated the LNA concentration, which improved meat quality through increased deposition of n-3 PUFA.

• Coleus amboinicus Lour. (CAL) into sheep diet decreased CH₄ emission.

• CAL did not reduce nutrient digestibility, but inhibited the methanogen community.

• CAL increased ruminal propionate proportion and decreased acetate/propionate ratio.

• CAL elevated n-3 fatty acid concentration in ruminal fluid and meat.

• Supplementation of CAL improved some meat quality traits.

Next Generation Sequencing of Single Nucleotide Polymorphic DNA-Markers in Selecting for Intramuscular Fat, Fat Melting Point, Omega-3 Long-Chain Polyunsaturated Fatty Acids and Meat Eating Quality in Tattykeel Australian White MARGRA Lamb

Meat quality data can only be obtained after slaughter when selection decisions about the live animal are already too late. Carcass estimated breeding values present major precision problems due to low accuracy, and by the time an informed decision on the genetic merit for meat quality is made, the animal is already dead. We report for the first time, a targeted next-generation sequencing (NGS) of single nucleotide polymorphisms (SNP) of lipid metabolism genes in Tattykeel Australian White (TAW) sheep of the MARGRA lamb brand, utilizing an innovative and minimally invasive muscle biopsy sampling technique for directly quantifying the genetic worth of live lambs for health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), intramuscular fat (IMF), and fat melting point (FMP). NGS of stearoyl-CoA desaturase (SCD), fatty acid binding protein-4 (FABP4), and fatty acid synthase (FASN) genes identified functional SNP with unique DNA marker signatures for TAW genetics. The SCD g.23881050T>C locus was significantly associated with IMF, C22:6n-3, and C22:5n-3; FASN g.12323864A>G locus with FMP, C18:3n-3, C18:1n-9, C18:0, C16:0, MUFA, and FABP4 g.62829478A>T locus with IMF. These add new knowledge, precision, and reliability in directly making early and informed decisions on live sheep selection and breeding for health-beneficial n-3 LC-PUFA, FMP, IMF and superior meat-eating quality at the farmgate level. The findings provide evidence that significant associations exist between SNP of lipid metabolism genes and n-3 LC-PUFA, IMF, and FMP, thus underpinning potential marker-assisted selection for meat-eating quality traits in TAW lambs.

LncIMF2 promotes adipogenesis in porcine intramuscular preadipocyte through sponging MiR-217

Intramuscular fat is positively related to meat quality including tenderness, flavor, and juiciness. Long noncoding RNA (LncRNA) plays a vital role in regulating adipogenesis. However, it is largely unknown about lncRNAs associated with porcine intramuscular adipocyte adipogenesis. In the present study, we focus on a novel LncRNA, which is named lncIMF2, associated with adipogenesis by our previous RNA-sequence analysis and bioinformatics analysis. We demonstrated LncIMF2 knockdown inhibited the proliferation of porcine intramuscular adipocytes while expression of cell cycle-related genes was decreased. Besides, we found LncIMF2 knockdown inhibited expression of adipogenic differentiation marker genes including PPARγ (Peroxisome proliferator-activated reporter gamma) and ATGL (Adipose triglyceride lipase). Similarly, overexpression of LncIMF2 promotes proliferation and differentiation of porcine intramuscular preadipocytes. Moreover, we proved that IncIMF2 acts as a molecular sponge for MicroRNA-217 (miR-217), which has been found associated with adipogenesis, thereby affecting the expression of the miR-217 target gene. Collectively, our findings will contribute to a deeper understanding of the role of LncRNA in pig IMF deposition for the improvement of meat quality.

Fat Deposition in the Muscle of Female and Male Yak and the Correlation of Yak Meat Quality with Fat

This study aimed to explore the differences in fat deposition between female (FYs) and male yaks (MYs). Compared with MYs, the tenderness, L*, marbling, absolute content of fat, and most fatty acids (FAs) of longissimus dorsi (LD) in FYs were higher or better (p < 0.05), whereas the relative content of polyunsaturated fatty acids (PUFAs) and n-3 PUFAs were lower (p < 0.01). The absolute content of fat, C18:0, cis-C18:2, cis-C18:1, and C24:0 were positively correlated with L*_{45 min}, b*_{24 h}, tenderness, and marbling score of LD in FYs and MYs (p < 0.05), respectively. LPL, FATP2, ELOVL6, HADH, HACD, and PLINS genes play a crucial role in improving the marbling score and tenderness of yak meat. The results of gene expression and protein synthesis showed the effect of gender to FA biosynthesis, FA transport, lipolysis, and FA oxidation in the adipose tissue of yak was realized by the expressions of ME1, SCD, ACSL5, LPL, FABP1, PLIN4, and PLIN2 in peroxisome proliferators-activated receptor (PPAR) signaling. This study established a theoretical basis for the improvement of the meat quality of yak and molecular breeding.

The Sources, Synthesis and Biological Actions of Omega-3 and Omega-6 Fatty Acids in Red Meat: An Overview

The maximisation of available resources for animal production, food security and maintenance of human-animal wellbeing is important for an economically viable, resilient and sustainable future. Pasture and forage diets are common sources of short chain omega-3 (n-3) polyunsaturated fatty acids (PUFA), while grain-based and feedlot diets are common sources of short chain omega-6 (n-6) PUFA. Animals deposit n-3 and n-6 PUFA as a result of their direct consumption, as feeds or by synthesis of longer chain PUFA from short chain FA precursors in the body via desaturation and elongation processes. Research conducted over the last three decades has determined that the consumption of n-3 PUFA can improve the health and wellbeing of humans through its biological, biochemical, pathological and pharmacological effects. n-6 PUFA also play an important role in human health, but when consumed at high levels, are potentially harmful. Research shows that current consumption of n-6 PUFA by the human population is high due to their meal choices and the supplied food types. If consumption of n-3 PUFA from land- and marine-based foods improves human health, it is likely that these same food types can improve the health and wellbeing of livestock (farm animals) by likewise enhancing the levels of the n-3 PUFA in their circulatory and tissue systems. Modern agricultural systems and advanced technologies have fostered large scale animal and crop production systems. These allow for the utilisation of plant concentrate-based diets to increase the rate of animal growth, often based on economics, and these diets are believed to contribute to unfavourable FA intakes. Knowledge of the risks associated with consuming foods that have greater concentration of n-6 PUFA may lead to health-conscious consumers avoiding or minimising their intake of animal- and plant-based foods. For this reason, there is scope to produce food from plant and animal origins that contain lesser amounts of n-6 PUFA and greater amounts of n-3 PUFA, the outcome of which could improve both animal and human health, wellbeing and resilience to disease.

Enhancing the Nutritional Value of Red Meat through Genetic and Feeding Strategies

Consumption of red meat contributes to the intake of many essential nutrients in the human diet including protein, essential fatty acids, and several vitamins and trace minerals, with high iron content, particularly in meats with high myoglobin content. Demand for red meat continues to increase worldwide, particularly in developing countries where food nutrient density is a concern. Dietary and genetic manipulation of livestock can influence the nutritional value of meat products, providing opportunities to enhance the nutritional value of meat. Studies have demonstrated that changes in livestock nutrition and breeding strategies can alter the nutritional value of red meat. Traditional breeding strategies, such as genetic selection, have influenced multiple carcass and meat quality attributes relevant to the nutritional value of meat including muscle and fat deposition. However, limited studies have combined both genetic and nutritional approaches. Future studies aiming to manipulate the composition of fresh meat should aim to balance potential impacts on product quality and consumer perception. Furthermore, the rapidly emerging fields of phenomics, nutrigenomics, and integrative approaches, such as livestock precision farming and systems biology, may help better understand the opportunities to improve the nutritional value of meat under both experimental and commercial conditions.

MARGRA Lamb Eating Quality and Human Health-Promoting Omega-3 Long-Chain Polyunsaturated Fatty Acid Profiles of Tattykeel Australian White Sheep: Linebreeding and Gender Effects

Health-conscious consumers increasingly demand healthier, tastier, and more nutritious meat, hence the continuous need to meet market specifications and demand for high-quality lamb. We evaluated the longissimus dorsi muscle of 147 Tattykeel Australian White (TAW) sheep fed on antioxidant-rich ryegrass pastures exclusive to MAGRA lamb brand for meat eating quality parameters of intramuscular fat (IMF) content, fat melting point (FMP) and omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). The aim was to assess the impact of linebreeding and gender on pasture-fed lamb eating quality and to test the hypothesis that variation in healthy lamb eating quality is a function of lamb gender and not its antioxidant status or inbreeding coefficient (IC). After solid-phase extraction and purification, phenolics and antioxidant enzyme activities were analysed by high-performance liquid chromatography and mass spectrometry. IMF and fatty acid composition were determined using solvent extraction and gas chromatography, respectively. IC was classified into low (0-5%), medium (6-10%) and high (>10%) and ranged from 0-15.6%. FMP and IMF ranged from 28 to 39 °C and 3.4% to 8.2%, with overall means of 34.6 ± 2.3 °C and 4.4 ± 0.2%, respectively, and n-3 LC-PUFA ranged from "source" to "good source" levels of 33-69 mg/100 g. Ewes had significantly (P ˂ 0.0001) higher IMF, C22:5n-3 (DPA), C22:6n-3 (DHA), C18:3n-6, C20:3, C22:4n-6, C22:5n-6, total monounsaturated (MUFA), PUFA and Σn-3 fatty acids and lower total saturated fatty acids (SFA) and FMP, than rams. As IC increased, there were no differences in FMP and IMF. Folin-Ciocalteu total phenolics, ferric reducing antioxidant power and antioxidant activities of glutathione peroxidase, catalase and superoxide dismutase enzymes did not differ by either gender or IC. This study provides evidence that IC is inconsequential in affecting antioxidant status, IMF, FMP and n-3 LC-PUFA in linebred and pasture-fed TAW sheep because the observed variation in individual fatty acids was mainly driven by gender differences between ewes and rams, hence the need to accept the tested hypothesis. This finding reinforces the consistent healthy eating quality of MARGRA lamb brand from TAW sheep regardless of its linebred origin.