Intramuscular Fat Content Research Articles

Composition of Donkey Meat (Equus Asinus) from the Puno Region, Peru

Objective: To determine the proximate chemical composition of donkey meat (Equus asinus) considering the variables of animal class (young and adult) and commercial cut (shoulder, rib and leg) with the purpose of nutritionally assessing it as an alternative source of red meat. Theoretical Framework: Donkey meat is characterized by a low intramuscular fat content and could be used as a valid alternative to other species of red meat such as beef and sheep in the Puno region, Peru. However, little is known about the nutritional quality of meat from donkeys that are slaughtered at the main equine slaughterhouse in southern Peru. Method: Muscle tissue samples were taken from the following muscles: deltoid, Longissimus dorsi and biceps femoris representing the commercial cuts of shoulder, rib and leg, respectively. Chemical analysis (moisture, protein, fat and ash) was performed following the protocols established for meat by the Association of Official Analytical Chemists (AOAC), in the Bromatology Laboratory of the Faculty of Veterinary Medicine and Zootechnics of UNA-Puno. Data analysis was performed in a randomized complete block design (DBCA) and the LSD significance test (α=0.05). Results and Discussion: The proximate chemical composition of donkey meat is as follows: moisture 73.79%, protein 19.23%, fat 4.53% and ash 1.20%. The animal class (young and adult) and the commercial cut (shoulder, rib and leg) have a significant effect on the moisture and fat content (p≤0.05), with an inverse relationship between the two; but there is no effect on the protein and ash content (p>0.05). Implications of the research: It was possible to demonstrate that the meat of donkeys from the Puno region has a similar composition to the red meat of other domestic species, so it can be a good alternative to replace red meat. Originality/Value: This study contributes to the literature by knowing the chemical composition of donkey meat from the Puno region, Peru for consumption purposes as a substitute for red meat or for the preparation of meat by-products.

High-concentrate diet supplemented with hydrolysable tannin improves the slaughter performance, intestinal antioxidant ability and barrier function of fattening lambs

The objective of current experiment was to study the potential influence of hydrolysable tannin supplementation on slaughter performance, meat quality, intestinal digestive enzyme activity, antioxidant ability and barrier function in fattening lambs. In total, 36 male Hu sheep lambs with similar body weight (15.83 ± 0.48 kg) and days in age (55 ± 2 d) were randomly assigned to one of three groups of 12 animals each: control without tannin (CON) and tannin supplementation groups (TA1, 3 g/d per lamb; TA2, 6 g/d per lamb). All the lambs were reared in individual hutches, and the experiment lasted for 60 d. On d 61, 8 lambs from each group were randomly selected to slaughter. Results showed that the serum diamine oxidase and lipopolysaccharide contents of TA2 group were higher (p < 0.05) than those of CON group. Compared with CON group, the carcass weight and intramuscular fat content of lambs in TA1 group were increased (p < 0.05) and the meat shear force was decreased (p < 0.05). The trypsin activity in the jejunum and ileum of TA1 group was higher (p < 0.05) than that of CON and TA2 groups. Also, tannin supplementation significantly increased (p < 0.05) the level of jejunal and ileal total antioxidant capacity and reduced (p < 0.05) the jejunal malondialdehyde concentration in lambs. The jejunum and ileum of TA1 lambs showed reduced (p < 0.05) tumor necrosis factor-alpha and increased (p < 0.05) interleukin-10 mRNA levels compared with CON lambs. In the jejunum, the secretory immunoglobulin A content of TA1 group was higher (p < 0.05) than that of CON and TA2 groups. Lambs supplemented with tannin at the level of 3 g/d increased (p < 0.05) the gene expressions of claudin-1, claudin-4 and zonula occludens-1 in the jejunum when compared to those of CON and TA2 groups. In summary, tannin supplementation at the level of 3 g/d per animal can improve the production performance and intestinal function of fattening lambs fed a high-concentrate diet.

Application of resistance exercise training combined with CT image evaluation in postoperative functional rehabilitation and fracture risk prediction of elderly femurs

ObjectiveTo evaluate the overall functional recovery of femoral patients, improve recovery ability, and prevent fractures in the elderly. MethodsA group of elderly femoral postoperative participants were selected and randomly divided into resistance exercise training and routine rehabilitation training. Simultaneously, a control group (without a history of fractures) and a fracture group (with a history of fractures) were designed to predict fracture risk. Finally, computerized tomography was used to evaluate the functional rehabilitation status. ResultsThe resistance exercise training group showed significantly better performance in functional rehabilitation and fracture risk prediction than the control group, and the decrease in Barthel index at 12 weeks after surgery in this group was 6.25 (P > 0.001). The age, gender, and volumetric bone density between the control group and the fracture group showed P > 0.001, and the differences were statistically significant. The average age of the control group was significantly higher than that of the fracture group, and the proportion of males in the fracture group was significantly higher than that of the control group. The intramuscular fat content of the iliopsoas muscle in the fracture group was significantly lower than that in the control group, P = 0.004. This indicated that lower intramuscular fat content of the iliopsoas muscle was associated with higher fracture risk, as participants with lower intramuscular fat content of the iliopsoas muscle had less bone protection, resulting in an increased risk of fracture. The difference in body mass index between the two groups was not statistically significant, P = 0.737, indicating that the impact of this parameter on fracture risk was not significant in this study. ConclusionResistance exercise training combined with CT image evaluation is an effective rehabilitation strategy with high clinical application value. This study provides reliable empirical evidence for the application of resistance exercise training and the combination of CT image evaluation, and provides guidance for the optimization of clinical rehabilitation strategies.

Effects of Acorns on Meat Quality and Lipid Metabolism-Related Gene Expression in Muscle Tissues of Yuxi Black Pigs

Objectives: The aim of this study was to investigate the effects of acorn diets on the composition of fatty acid (FA) and the intramuscular fat (IMF) content in Yuxi black pigs. Methods: Ninety Yuxi black pigs with similar body weight (99.60 ± 2.32 kg) were randomly divided into five groups. The control group was fed a basal diet, and the AD20, AD30, AD40, and AD50 groups were fed experimental diets which contained 20%, 30%, 40%, and 50% acorns, respectively. The feeding experiment lasted for 120 days. Results: The results showed that compared with the control group, the content of SFA in longissimus dorsi and biceps femoris tissues in the AD30 group decreased by 8.57% and 20.10%, and the content of MUFA increased by 5.40% and 15.83%, respectively, while the PUFA content of biceps femoris increased by 5.40% (p < 0.05). Meanwhile, the IMF content of the AD30 group was significantly higher than that of the control group in the longissimus dorsi and biceps femoris. In addition, the mRNA expression levels of the ATGL, PPARγ, and FABP4 genes in longissimus dorsi (p < 0.05) were up-regulated, and HSL were down-regulated (p < 0.05) in the AD30 group. In the biceps femoris of the AD30 group, it was observed that the expression levels of the ACC and FAS genes were up-regulated (p < 0.05), while HSL and ATGL genes were down-regulated (p < 0.05). Conclusions: These results demonstrated that the addition of appropriate amounts of acorn to the diet (a 30% acorn diet) could improve the nutritional value of pork.

LncBNIP3 Inhibits Bovine Intramuscular Preadipocyte Differentiation via the PI3K-Akt and PPAR Signaling Pathways.

Intramuscular fat (IMF) content is an economic trait in beef cattle that improves the meat quality. Studies have highlighted the correlation between long noncoding RNAs (lncRNAs) and IMF development. In this study, lncBNIP3 knockdown promoted bovine intramuscular preadipocyte differentiation. RNA-seq analysis of intramuscular preadipocytes with lncBNIP3 knockdown identified 230 differentially expressed genes. The PI3K-Akt and PPAR signaling pathways were enriched. lncBNIP3 interference promoted mRNA and protein expression of key genes in PI3K-Akt signaling pathway. LncBNIP3 interference reversed the effects of an AKT-inhibitor MK-2206 on Akt protein expression and lipid droplet accumulation, promoted mRNA and protein expression of essential genes in the PPAR signaling pathway, and ameliorated the inhibitory effects of a PPARg antagonist GW9662 on lipid accumulation. Therefore, lncBNIP3 inhibition of bovine intramuscular preadipocyte differentiation is likely mediated via the PI3K-Akt and PPAR signaling pathways. This study identified a valuable lncRNA with functional roles in IMF accumulation and revealed new strategies to improve beef quality.

Productive, Physiological, and Environmental Implications of Reducing Crude Protein Content in Swine Diets: A Review

Pig production is one of the most important providers of high-quality proteins and amino acids (AAs) to human nutrition. In this sector, feeding has an important economic and environmental impact. A strategy to reduce production costs and negative sustainability effects is reducing dietary crude protein (CP) contents with or without AA supplementation. This review addresses the different aspects related to this strategy, particularly the effects on growth performance and pork traits in piglets and growing and finishing pigs, as well as the physiological molecular mechanisms’ underlying effects. Insight is also provided into the effects of dietary CP reduction on the productive performances of alternative pig production systems and breeding boars and sows. Finally, an overview is conducted on the effects of dietary CP reduction on ammonia, odor, and greenhouse gas emissions arising from pig production systems. Overall, CP reduction may lead to production losses, albeit they can be, to some extent, hindered by adequate AA supplementation. Losses are particularly relevant during the post-weaning phase, whereas in finishing pigs, it may bring additional benefits, such as high intramuscular fat contents in some markets or improved gut barrier function with benefits to the animals’ health and welfare, as well as decreased ammonia emissions to the environment.

Integrated analysis of muscle lncRNA and mRNA of Chinese indigenous breed Ningxiang pig in four developmental stages

Meat and its derivatives serve as crucial sources of protein, vitamins, minerals, and other essential nutrients for humans. Pork stands as China’s primary animal-derived food product consumed widely across diverse dietary structures; evaluating intramuscular fat content becomes pivotal in assessing its quality standards. Nonetheless, the intricate molecular mechanisms governing intramuscular fat deposition remain elusive. Our study utilized sequencing technology to scrutinize longitudinal development stages within Ningxiang pig’s longest dorsal muscles aiming to unravel these underlying mechanisms. In three distinct comparisons (30d vs. 90d, 90d vs. 150d and 150d vs. 210d) there were 578, 1,000 and 3,238 differentially expressed mRNA, along with 16, 158 and 85 lncRNAs were identified. STEM analysis unveiled six enriched model profiles for lncRNAs while seven such profiles emerged for mRNAs; notably, multiple shared model profiles existed between both RNA types. Enriched analysis highlighted numerous genes from mRNA profile8 and lncRNA profile7 significantly associated with pathways linked to fat deposition. Weight Gene Co-Expression Network Analysis (WGCNA) revealed that differential expression modules (DMEs) & differential expression lncRNAs primarily clustered within cyan, dark slate blue and pale turquoise modules. Furthermore, target genes PKD2 (MSTRG21592.MTRSG8859 and MTRSG18175), COL5A1 (MTRSG9969 and MTRSG180) and SOX13 (MTRSG21592 and MTRSG9088) as core components all intricately tied into processes related to fat deposition. This study lays the groundwork for deeper exploration into the molecular mechanisms underlying LDM fat deposition traits, and it also presents candidate genes for future molecular marker-assisted breeding.

Overexpression of ALDOC Promotes Porcine Intramuscular and Intermuscular Fat Deposition by Activating the AKT-mTORC1 Signaling Pathway.

Skeletal muscle fat accumulation, a common complication of obesity, has garnered increasing attention. For livestock animals, intramuscular fat content is a key determinant of meat quality and directly influences consumer preferences for different meat products. However, genes effectively regulating intramuscular and intermuscular fat (IIMF) deposition remain largely unexplored. To address this gap, we employed transcriptome sequencing of muscle from pigs with high and low IIMF contents, uncovering Aldolase C (ALDOC) as a novel key gene controlling IIMF. ALDOC overexpression significantly enhanced the IIMF content both in vivo and in vitro. Mechanistic investigations revealed that ALDOC activates the AKT-mTORC1 axis to promote lipid accumulation in myotubes and intramuscular adipocytes. Notably, the mTORC1 inhibitor rapamycin abrogated ALDOC's proadipogenic effect. Our findings establish ALDOC as a novel key gene regulating IIMF deposition and identify the ALDOC-AKT-mTORC1 signaling pathway as a promising therapeutic target for treating skeletal muscle fat infiltration and improving pork quality.

Two-Stage Multimodal Method for Predicting Intramuscular Fat in Pigs

Intramuscular fat (IMF) content significantly influences pork tenderness, flavor, and juiciness. Maintaining an optimal IMF range not only enhances nutritional value but also improves the taste of pork products. However, traditional IMF measurement methods are often invasive and time-consuming. Ultrasound imaging technology offers a non-destructive solution capable of predicting IMF content and assessing backfat thickness as well as longissimus dorsi muscle area size. A two-stage multimodal network model was developed in this study. First, using B-mode ultrasound images, we employed the UNetPlus segmentation network to accurately delineate the longissimus dorsi muscle area. Subsequently, we integrated data on backfat thickness and longissimus dorsi muscle area to create a multimodal input for IMF content prediction using our model. The results indicate that UNetPlus achieves a 94.17% mean Intersection over Union (mIoU) for precise longissimus dorsi muscle area segmentation. The multimodal network achieves an R2 of 0.9503 for IMF content prediction, with Spearman and Pearson correlation coefficients of 0.9683 and 0.9756, respectively, all within a compact model size of 4.96 MB. This study underscores the efficacy of combining segmented longissimus dorsi muscle images with data on backfat thickness and muscle area in a two-stage multimodal approach for predicting IMF content.

The Effects of Concentrate Supplement Levels on Feed Utilization and Red Meat Production of Blackhead Somali Sheep Fed Natural Pasture Grass Hay as a Basal Diet.

In recent years, consumers have become aware of their health, and their preference has been rapidly changing to consume less fatty meat. Therefore, devising a strategy to produce lean meat is a concern in this study. One of the strategies, among others, for lean meat production is controlling the amount of supplements given to sheep. Hence, muscle (lean) and adipose tissue (fat) require different amounts of energy to lie down. This study was conducted to evaluate the effects of concentrate supplementation levels on feed utilization and red meat production in Blackhead Somali sheep (BHS) fed natural pasture grass hay as a basal diet. A total of 16 BHS sheep weighing 19.5±0.2kg (mean±SE) at the beginning of the experiment were kept for 90 days by feeding two levels (1% [T1] and 1.75% [T2] body weight [BW] of sheep) of supplement. The sheep were blocked according to their initial BW (IBW), and the supplements were randomly assigned within a block. At the end of the feeding period, all sheep were slaughtered, and carcass and non-carcass data were recorded. Data were analysed using the SAS software version 9.1 of PROC GLM programme. Sheep fed T1 and T2 consumed 6.1 and 8.2MJ/day metabolizable energy (ME), respectively, and 73.1 and 93.6g/day crude protein (CP), in that order. Consequently, sheep fed T2 produced 1.37kg extra BW by growing an average rate of 15g/day greater (p<0.0001) over their counterpart fed T1. They also produced 0.9kg, 0.8 cm2 and 2.64% heavier carcasses, a wider rib eye area and a higher intramuscular fat content (p<0.0001), respectively, over the sheep fed T1. On the other hand, the lean-to-fat ratio was significantly lower in sheep fed T2 than T1. In most parameters considered in this study, sheep fed T2 (1.75% BW) were superior, but its intramuscular fat (IMF) content was much higher than the limit that the consumers needed. Therefore, it can be concluded that 1% BW supplementation is enough for BHS to produce lean meat containing the optimal fat content in stall feeding condition.

Multi-omics analysis of chemical composition variation among different muscle types in Hu lamb.

Consumers' preferences for lamb meat vary greatly depending on the specific cut. Variations in the chemical composition across different muscle types play a crucial role in determining meat quality, particularly with regard to flavor. Therefore, it is essential to study the variations in chemical composition among different muscle types in lamb, as well as the mechanisms behind their formation, aiming to understand the flavor variation across the muscle types. Flank muscles showed significantly higher intramuscular fat content and muscle fiber diameter compared to triceps brachii and biceps femoris (BF), at the same time as displaying a significantly lower percentage of type I muscle fibers. Forty-three differentially abundant volatile compounds (DAVC) were identified across five muscles, with the majority of DAVCs being more abundant in the BF. In total, 161 differentially abundant lipids were identified across five muscles, with triglycerides (TG), phosphatidylcholines (PC), phosphatidyl ethanolamines (PE) and phosphatidylmethanol (PMeOH) showing a strong correlation with DAVCs. A lipid-gene regulatory network was established, encompassing 664 lipids and 11 107 genes, leading to the identification of pathways and genes that regulate the metabolism of PEs, PMeOH, PCs and TGs. The present study showed the significant variation in flavor compounds among the five edible muscles, as well as the potential reasons for their formation. The results potentially provide a theoretical foundation for improving the meat quality of lamb. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

Comparative analysis of production performance, carcase traits, and meat quality in yearling beef of Limousine, Sardo-Bruna, and their crosses

The aim of this study was to compare animal performance and meat quality of a local cattle breed of Sardinia Island with specialised meat purebred or obtained by crossbreeding. For this purpose, 10 Sardo-Bruna (SB; 5 males, 5 females), 10 Limousine (L; 5 males, 5 females) and 10 Limousine × Sardo-Bruna crossbreed (L × SB; 5 males, 5 females) were compared simultaneously from 12 to 20 ± 1 (mean ± SEM) months old. During the trial, body weight (BW) was recorded once a month for estimating the average daily gain (ADG). At slaughter, carcase measurements, pH and colour traits were recorded from the left side of the carcase. Proximate composition, fatty acid (FA) profile, cooking and drip losses were evaluated using the Longissimus thoracis et lumborum muscle. The SB group showed a lower cold carcase yield compared to L and L × SB genetic types. Males had a higher ADG, slaughter weight, hot and cold carcase weights, hot and cold carcase yields, and cooking losses than females. Females group showed a higher intramuscular fat content and rib fat thickness compared to males. No relevant differences among genetic types and between sexes were observed for meat and fat colours and pH. Concerning the FA profile, SB genetic type evidenced a higher oleic acid content and a better nutritional index than other genetic types while males had a higher PUFA content than females. In conclusion, the results of this study showed that the Limousine breed can be effectively used to enhance carcase yield of local breed without effects on meat quality.

Integrating spatial transcriptomics and single-nucleus RNA-seq revealed the specific inhibitory effects of TGF-β on intramuscular fat deposition.

Intramuscular fat (IMF) is a complex adipose tissue within skeletal muscle, appearing specially tissue heterogeneous, and the factors influencing its formation remain unclear. In conditions such as diabetes, aging, and muscle wasting, IMF was deposited in abnormal locations in skeletal muscle, damaged the normal physiological functions of skeletal muscle. Here, we used Longissimus dorsi muscles from pigs with different IMF contents as samples and adopted a method combining spatial transcriptome (ST) and single-nucleus RNA-seq to identify the spatial heterogeneity of IMF. ST revealed that genes involved in TGF-β signaling pathways were specifically highly enriched in IMF. In lean pigs, IMF autocrine produces more TGF-β2, while in obese pigs, IMF received more endothelial-derived TGF-β1. In vitro experiments have proven that porcine endothelial cells in a simulated high-fat environment released more TGF-β1 than TGF-β2. Moreover, under obesity mice, the addition of TGF-β after muscle injury abolished IMF production and slowed muscle repair, whereas TGF-β inhibition accelerated muscle repair. Our findings demonstrate that the TGF-β pathway specifically regulates these processes, suggesting it as a potential therapeutic target for managing muscle atrophy in obese patients and enhancing muscle repair while reducing IMF deposition.

Integrative multiomics analysis identifies key genes regulating intramuscular fat deposition during development

Intramuscular fat (IMF) content is an important indicator of livestock and poultry meat quality. Enhancing IMF deposition can significantly improve meat quality. Focusing on the core process of IMF deposition, this study used the Jingxing Yellow (JXY) chickens as a model organism and employed multi-omics approaches, including RNA-sequencing (RNA-seq), Whole-genome bisulfite sequencing (WGBS), and metabolomics, to identify the key genes influencing IMF deposition in chickens during development. The results indicated that the contents of triglycerides (TG) and phospholipids (PLIP) exhibited an upward trend. The TG content did not differ significantly between day 1 (D1) and day 7 (D7), but increased significantly after 35 days (D35) of age. The WGBS results revealed that CpG methylation was the predominant methylation type in the breast muscle tissue of JXY chickens. Integrative analysis of RNA-seq and WGBS identified 50 genes, including PLA2G4F, PALMD, PLSCR5, ARHGEF26, LUM, DCN, TNRC6B, CACNA1C, ROBO1, and MBTPS2, whose methylation levels were significantly negatively correlated with their expression levels. In addition, the combined Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of differentially-expressed metabolites (DEM) and differentially-expressed genes (DEG) converged on the glycerophospholipid metabolism pathway, which was significantly enriched in DEGs such as PLA2G4F, PLA2G15, LPIN1, MBOAT2, DGKH, AGPAT2, and CHKA, as well as DEM like glycerophosphocholine and phosphocholine. Notably, PLA2G4F was identified as a DEG by DNA methylation, suggesting that PLA2G4F could be a key candidate gene influencing IMF deposition during chicken development. These findings are expected to provide a solid theoretical foundation for improving meat quality through targeted genetic and epigenetic interventions.

Changes in the Objective Indices Related to Meat Quality of Porcine Longissimus Dorsi Induced by Different Thawing Methods.

The quality of frozen pork is adversely affected upon thawing. In this study, the influence of various thawing methods for frozen pork, including cold water (18 °C), room temperature (18 °C), and refrigeration (4 °C) thawing, on physicochemical and nutrient substances were examined. The pork samples (a Chinese local breed: Anqing six-end-white pigs), which were thawed through the above conditions, were compared with controls (fresh porcine longissimus dorsi). Analyses were carried out to determine porcine longissimus dorsi shear force, pH value, crude protein content, antioxidant capacity, amino acid content, and fatty acid content. The results indicated that the shear force, pH value, crude protein content, total antioxidant capacity (T-AOC), and total superoxide dismutase (T-SOD) content of the porcine longissimus dorsi muscle significantly decreased via the three thawing methods compared with the control group (p < 0.05). However, malondialdehyde (MDA) content, intramuscular fat content, inosinate and cholesterol content, essential amino acid content, and umami amino acid proportion in the cold thawing group were not significantly different from the control group (p > 0.05), but there were significant differences between the other two groups. The MDA content of the air thawing and hydrostatic thawing groups significantly increased compared with the control group (p < 0.05), with it being 42.6% and 50.8% higher than the control group, respectively. In addition, the monounsaturated fatty acid content in the pork subjected to the three thawing methods significantly increased compared with the control group (p < 0.05), and the monounsaturated fatty acid content after cold thawing and hydrostatic thawing increased by 18.2% and 21.6%, respectively. In conclusion, refrigeration had less influence on the quality of the Anqing six-end-white pork and was the most suitable thawing method. This study provides a theoretical reference for frozen pork preservation for improving food quality and availing its economic benefits.

Quality and Processability of Meat in Polish Native Pigs – A Review

Abstract The primary aim of pig breeding efforts is to produce animals characterized by outstanding performance, including also fattening and slaughter performance traits. However, improved carcass leanness and reduced carcass fatness, especially intramuscular fat content, have led to a deterioration of pork quality and processability. Due to the growing frequency of meat defects and the limited potential use of such meat in the production of premium products this constitutes a considerable problem for the meat industry. The breeds superior in terms of meat quality are native pig breeds, such as those kept in Poland, i.e. Pulawska (Pul), Zlotnicka Spotted (ZS) and Zlotnicka White (ZW) pigs. The aim of this paper is to present a review of research results concerning quality and processability of meat produced by the Polish native pig breeds. The presented results indicate that pigs of local breeds exhibit a low level of performance traits (daily gain, carcass leanness, backfat thickness) while maintaining very good parameters of meat quality and processability (muscle composition and physical properties, fatty acids profile, sensory traits). Thus, they are used as a source material for premium products. In view of the small size of local populations and higher production costs in Poland it is a niche production. Therefore, the current aim of breeding indigenous breeds is both to maintain a safe population size and genetic diversity and to increase popularity of their meat and processed meat products among consumers. This objective is attained, among other things, thanks to efforts to reduce cost of their production through optimization of environmental conditions and wider use of less expensive traditional feed formulations, which make it possible to fully utilize the potential of local pork resources.

Effects of Supplementation with Essential Fatty Acids and Conjugated Linoleic Acids on Muscle Structure and Fat Deposition in Lactating Holstein Cows

High-yielding dairy cows need diets that meet their energy demand and contain sufficient essential nutrients such as n-3 fatty acids (FAs). Conjugated linoleic acid (CLA) is able to relieve the energy metabolism, but common corn silage and concentrate-based diets contain insufficient amounts of essential fatty acids (EFA). Abomasal infusion was used in the current study to supplement cows from 9 weeks antepartum to 9 weeks postpartum with either coconut oil (CTRL, n = 8), EFA (n = 9), or conjugated linoleic acid (CLA, n = 9), or a combination of both (EFA + CLA, n = 10). The study focused on the effects of FAs on peripheral tissues, such as longissimus muscle (MLD) and adipose tissues, which were harvested after slaughter. Fatty acid composition, muscle fiber and fat cell morphology, muscle fiber type transition, and gene expression were analyzed. Supplemented FAs and their metabolites were increased (p &lt; 0.05) in MLD and intermuscular fat (INTF) but not in subcutaneous fat (SCF). The intramuscular fat content and gene expression of ACACA and FASN were increased in CLA-supplemented cows (p &lt; 0.05). Supplementation did not affect the muscle fiber size and fiber type composition. Supplemented CLA had more effects than EFA, improving the energy balance of cows accompanied with increased triglyceride formation and storage.

Saturated Fatty Acids in Wool as Markers Related to Intramuscular Fat Content in Lambs.

The aim of this study was to identify Longissimus lumborum (LL) muscle from lambs with high IMF content (≥3%) using wool FA. The FA composition was characterized in two sections of wool from Suffolk Down lambs, and its relationship with IMF content assessed. One hundred and forty lambs of similar body weight, body condition score, and age were selected. IMF content from LL muscle, and the wool fat and FA composition of the wool were determined. The proportions of FAs in the wool of lambs with low IMF were 51.96 ± 7.3% of saturated, 31.96 ± 7.7% polyunsaturated, and 16.08 ± 2.3% monounsaturated. Similar proportions of FAs were observed in wool samples of lambs with high IMF. Significant differences were found only in the SFA proportion between groups (p < 0.05). The predominant FAs in the wool samples were C16:0, C17:0, C18:0, C18:1n9c and C18:2n6c, representing over 60% of total FA methyl esters. Correlations were found between the wool FAs C16:1, C17:0, C18:0, C18:1n9c, C24:0, and C22:6n3 in wool samples divided into two sections. Discriminant analysis identified SFAs, particularly FAs C22:0 and C24:0, as potential candidate for predicting lambs with high IMF content with an accuracy of over 92%. These results provide to our knowledge evidence that IMF content could potentially be determined using wool FAs as a non-invasive method.

Dry-ageing impacts on meat quality, oxidative stability, and release of free amino acids in striploins from dairy crossbred yearling and 2-year-old steers

This study determined the impacts of dry-ageing on meat quality, oxidative stability, and release of free amino acids (FAAs) in striploins from dairy-crossbred yearlings and 2-year-old steers (n = 12 each group) over 21 days of in-bag dry-ageing. Dry-ageing increased weight losses, with higher % drying rates in yearling meat during dry-ageing, likely due to the smaller loin size and lower intramuscular fat content (P < 0.05). Yearling meat showed greater (P < 0.05) decreases in moisture content, but both meats reached similar moisture levels by day 21. pH values increased with dry-ageing with variations at different ageing times. Dry-ageing reduced a*, b*, and chroma while increasing L* and hue angles on day 21 (P < 0.05), likely due to dehydration and lipid oxidation (higher TBARS, P < 0.05) after 14 days, especially in yearling meat. The decreased levels (P < 0.05) of some monounsaturated fatty acids and conjugated linoleic acid cis-9, trans-11 were likely linked with lipid oxidation. Total levels of FAAs and essential amino acids increased significantly, especially within the first 7 days, with distinct patterns between the two meats. Dry-aged yearling meat contained more FAAs associated with sweat taste (e.g., glutamine and glycine) and fewer FAAs associated with bitter taste (e.g., phenylalanine and tyrosine). Carnosine levels varied and significantly increased after 21 days. Dry-ageing demonstrated distinct effects on dehydration, lipid oxidation, and release of FAAs in meat from yearlings compared with 2-year-old steers, which can be tailored to develop high-quality beef products with unique flavours.

Effects of Feeding Systems on the Growth Performance, Carcass Characteristics, and Meat Quality in Sheep: A Meta-Analysis.

Meat quality is important in the meat-production chain. Conflicting reports of the effects of feeding systems on sheep growth performance and meat quality exist. By way of meta-analysis, we reviewed the literature on the growth and slaughter performance, and meat quality of lambs that grazed solely on pasture, those that grazed on pasture but received a dietary supplement, and those were exclusively fed indoors. The relevant literature comprised 28 papers, from which response variables of interest were obtained. Compared with stall-fed sheep, pasture-grazing led to significantly (p < 0.05) lower average daily gain, slaughter live weight, hot carcass weight, cold carcass weight, and similar dressing percentage, but pasture-grazed sheep fed a supplement had similar (p > 0.05) values for each of these attributes to stall-fed sheep. The quality of the longissimus muscle from lambs that grazed either exclusively on pasture or pasture with a supplement had significantly (p < 0.05) lower lightness and intramuscular fat content, and significantly (p < 0.05) higher yellowness, Warner-Bratzler shear force, and protein content than meat from stall-fed sheep. We conclude that sheep that have fed exclusively on pasture have lower carcass yield and meat edibility, but improved meat quality, and that pasture-fed sheep that received a supplement had comparable carcass attributes, but greater meat color and health quality than stall-fed sheep.