Nutritional enhancement of sheep meat fatty acid profile for human health and wellbeing

Effect of coconut processing by-product graded feeding on carcass traits and meat quality of lambs

The inclusion of by-product coconut mesocarp skins (CMS) in diets was evaluated in feedlot lambs. The objective of this study was to evaluate CMS levels effects on carcass traits and meat quality of lambs. Thirty-five male lambs with an initial body weight of 16.9 ± 2.93 kg were distributed in a completely randomized design with five CMS levels in total dry matter (0; 4.8; 9.6; 14.4 and 19.2%) and fed during 71 d until slaughter. High levels of CMS decreased the intake of dry matter and negatively affected the performance of lambs. Fat and protein contents of Longissimus lumborum muscle (P < 0.05) and the saturated fatty acid (FA) decreased (P < 0.001) whereas polyunsaturated FA increased (P < 0.01) with the inclusion of CMS. The ratio t10/t11-18:1 increased with the inclusion of CMS (P < 0.001). The instrumental color descriptors were unaffected by CMS levels. According to the effects on the investigated meat quality traits we recommend up to 4.8% CMS in diets of confined lambs.

The comparison of meat yield, quality, and flavor between small-tailed Han sheep and two crossbred sheep and the verification of related candidate genes

Introduction

In Northeast China, Dorper and Australian White rams are commonly crossbred with small-tailed Han (STH) ewes to improve the offspring's meat yield and quality. However, the differences in traits and the flavor between the crossbred sheep and STH sheep remain unclear. In addition, the candidate genes potentially influencing the meat quality in the three sheep breeds require further verification.

Methods

A total of 18 2-month-old healthy rams were raised over a period of 5 months, which included 6 STH, 6 Dorper and small-tailed Han crossbred (Do × STH), and 6 Australian white and small-tailed Han crossbred (Au × STH) offspring. The differences in slaughter, meat quality traits, fatty acid and amino acid composition in the muscular longissimus dorsi (MLD), and volatile compounds in the semitendinosus muscle were compared between the sheep breeds. The candidate genes related to intramuscular fat (IMF) content and fatty acids were validated.

Results

The results of this study revealed that the crossbred sheep had higher body weight, carcass weight, bone weight, net meat weight, and IMF content than the STH sheep (p < 0.05). The Do × STH offspring had a higher pH value (24 h), moisture content, and cooking percentage; they also had redder and brighter meat color. The content of myristate, palmitic, and margaric acids in the crossbred sheep was higher than that in the STH sheep (p < 0.05). The Do × STH offspring had the highest saturated fatty acid content (p < 0.05). The Au × STH offspring had the highest protein content (p < 0.05). The arachidonic acid and amino acid (Asp, Ala, Ile, Leu, Lys, Thr, and essential amino acid) contents were higher in the STH sheep than in the crossbred sheep (p < 0.05). The odor activity value (OAV) analysis showed that most of the aldehydes in the Au × STH offspring had higher values. The PDK4 gene expression was positively associated with the IMF content and was negatively correlated with the linoleic acid content in the Do × STH sheep (p < 0.05). The TMEM273 gene expression was positively associated with linoleic and arachidonic acid contents and was negatively correlated with oleic and palmitic acid contents in the Do × STH sheep (p < 0.05).

Discussion

The results showed the differences between the crossbred sheep and STH sheep and provided the candidate genes related to meat quality in sheep.

The effects of the feeding duration of propylene glycol on major meat quality parameters and substantial proteins in the muscle of Akkaraman lambs

In this study, the effects of propylene glycol (PG) on meat quality and molecular pathways related to energy metabolism in longissimus lumborum muscle on lambs were evaluated. Seventy-two lambs were divided into three groups consisting of 60th, 90th, and 120th of slaughter days. The dosage of the PG and slaughter days were the variables used in the study. Eight animals were slaughtered from each group on each day. The meat quality parameters (e.g., pH, protein, fatty acid profile) and IGF-1, IGFBP4, and DGAT1 (i.e., mRNA and protein levels) were evaluated. The pH 45 min post-slaughter was higher in PG groups on 120th day. On the 4th day after slaughter, the b value was the lowest in the PG3, while 7th day after slaughter it was highest in Con and PG3 on 90th day. The total n3 and n6 were lowest and the NV was highest on 120th day. The IGFBP4 was upregulated in the PG groups on all of the slaughter days. The DGAT1 was upregulated in the PG3 on the 90th day. The IGF-1, DGAT1, IGFBP4 protein levels were found to have increased in the PG3 on 90th day. The IGFBP4 was found to have decreased in the PG3 on 120th day. According to the results of the study, the oral administration of the PG at the 3 mL/kg live weight0.75 for at least 120 days may have positive effects on meat quality in lambs through the IGF-1, DGAT1, and IGFBP4 genes and the proteins encoded by these genes.

Effect of dawri-damaa (Pentas schimperiana) leaf meal supplementation on performances, carcass characteristics, and economic feasibility of sheep fed native grass hay

With a growing export and local market, sheep farming is critical to the economy of smallholder farmers; however, indigenous sheep breeds usually exhibit low carcass output and live weight due to nutritional constraints. The study aimed to investigate the impact of supplementing local sheep with dawri-damaa leaf meal (DDLM) on their performance, carcass characteristics, and profitability when fed native grass hay. The research used a randomized complete block design (RCBD) to administer four feeding treatments (T1, T2, T3, and T4 at 0%, 30%, 50%, and 70% DDLM, respectively) to 20 local uncastrated male lambs having an average 23.72 ± 0.73 kg body weight and average age of 11.72 ± 0.74 months. Greater doses of DDLM in the diet resulted in greater average daily gain (ADG) of 51.4-83.8 g/day and feed conversion efficiency (FCE) of 0.066-0.089 in lambs, compared to 15.0 g/day ADG and 0.025 FCE in lambs under control diet (T1). Additionally, the lambs had increased slaughter body weight (SBW), empty body weight (EBW), and hot carcass weight (HCW) in T4 and T3 compared to other treatments (p < .05). There were no significant differences in dressing percentages (DPs) across any treatment group. The study also discussed the economic viability of supplementing with DDLM, suggesting that feeding 70% daily dry matter of DDLM at 2.5% live weight might be beneficial depending on availability, access, and cost factors. In conclusion, feeding DDLM up to 70% has improved the performance of sheep and is economically feasible. Further research might be required to discover whether such levels of inclusion are harmful and apply different processing methods for feeding animals.

Lipase-catalyzed interesterification of Sunite sheep tail fat and flaxseed oil provides a fat having a unique fatty acid content and favorable physicochemical and nutritional properties

The aim of this study is to combine flaxseed oil (FO), rich in α-linolenic acid (ALA), with Sunite sheep tail fat (STF) through a lipase-catalyzed transesterification reaction, in order to produce an edible oil with a fatty acid ratio suitable for human needs. Initially, the optimal conditions for esterification were determined using the Box-Behnken design, with the measurement criterion being the content of ALA at the sn-2 position. The results indicated that the highest content of sn-2 ALA was obtained under the conditions of using 6.8 wt% Lipozyme®RMIM as the catalyst, a reaction temperature of 57°C, a reaction time of 3.3 h, and a substrate mass ratio of 5.6:4.4 for STF and FO. This led to the rapid breaking and recombining of molecular bonds, resulting in the interesterified fat (IF) with the highest content of ALA at the sn-2 position. Comparing STF and FO, IF exhibited excellent fatty acid composition and content. Furthermore, IF had a lower melting point and crystallization temperature compared to STF, and its solid fat content decreased with increasing temperature, completely melting at temperatures above 30°C. Thus, IF is a synthesized fat with excellent properties from both animal and vegetable sources.

Strategies for Healthier Meat Foods: An Overview

Functional food products remain the focus of current market trends toward healthier nutrition. The consumption of meat-based functional foods has been a topic of interest in food innovation since some of these products generate controversy due to their possible adverse effects on health. However, studies have demonstrated that meat-based functional products are considered an opportunity to improve the nutritional profile of meat products through the addition of biologically valuable components and to meet the specific needs of consumers. In this sense, some strategies and techniques are applied for processing and developing functional meat products, such as modifying carcass composition through feeding, reformulating meat products, and processing conditions. This review focuses on presenting developed and evaluated strategies that allow the production of healthy and functional meat foods, which application has successfully achieved the sensory, nutritional, and technological parameters mainly affected by such application.

Nutritional Quality and Safety Assessment of Pork Meat Cuts from Romania: Fatty Acids and Elemental Profile

In this study, the fatty acids and elemental profiles of 53 pork cut samples were determined. To offer insights into their potential health implications, we computed 18 key nutritional indices. These indices included parameters such as saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), unsaturated fatty acids (UFAs), the MUFAs/SFAs ratio, PUFAs/SFAs ratio, atherogenic index (AI), thrombogenic index (TI), the hypocholesterolemic to hypercholesterolemic ratio (h/H), health-promoting index (HPI), hypocholesterolemic index (HI), unsaturation index (UI), saturation index (SI), peroxidizability index (PI), nutritional value index (NVI), hypocholesterolemic index of fatty acids (DFAs), hypercholesterolemic index of fatty acids (OFAs), and the DFAs/OFAs ratio. These indices were calculated based on their fatty acid composition to provide comprehensive nutritional information. A health risk assessment revealed the safety and minimum health risk for the population from consuming the investigated pork cuts using the Target Hazard Quotient (THQ), Hazard Index (HI), and target cancer risk (TR). The ANOVA test showed significant differences in the levels of K, Fe, Mn, Zn, MUFAs, and AI among the pork cut samples. It was noted that by employing the correlation between the fatty acids profile, nutritional indices, and elemental concentrations and an unsupervised statistical method, such as PCA, a perfect separation from the different pork cuts could not be obtained.

Inclusion of exogenous enzymes in feedlot cattle diets: Impacts on physiology, rumen fermentation, digestibility and fatty acid profile in rumen and meat

The objective of this study was to evaluate if the inclusion of a blend composed of exogenous enzymes (amylase, protease, cellulase, xylanase and beta glucanase) in the individual and combined form in the feedlot steers diet has benefits on the physiology, rumen fermentation, digestibility and fatty acid profile in rumen and meat. The experiment used 24 animals, divided into 4 treatments, described as: T1-CON, T2-BLEND (0.5 g mixture of enzyme), T3-AMIL (0.5 g alpha-amylase), T4-BLEND+AMIL (0.5 g enzyme blend+ 0.5 g amylase). The concentration of mineral matter was higher in the meat of cattle of T4-BLEND+AMIL. A higher proportion of monounsaturated fatty acids was observed in the T3-AMIL group when compared to the others. The percentage of polyunsaturated fatty acids was higher in the T2-BLEND and T4-BLEND+AMIL compared to the T1-CON. The combination of exogenous enzymes in the diet positively modulate nutritional biomarkers, in addition to benefits in the lipid and oxidative profile meat.

Study of the Interactions between Muscle Fatty Acid Composition, Meat Quality-Related Genes and the Ileum Microbiota in Tibetan Sheep at Different Ages

The intestinal microbiota of ruminants is an important factor affecting animal production and health. Research on the association mechanism between the intestinal microbiota and meat quality of ruminants will play a positive role in understanding the formation mechanism of meat quality in ruminants and improving production efficiency. In this study, the fatty acid composition and content, expression of related genes, and structural characteristics of the ileum microbiota of ewes of Tibetan sheep at different ages (4 months, 1.5 years, 3.5 years, and 6 years) were detected and analyzed. The results revealed significant differences in fatty acid composition and content in the muscle of Tibetan sheep at different ages (p < 0.05); in addition, the content of MUFAs in the longissimus dorsi muscle and leg muscle was higher. Similarly, the expressions of muscle-related genes differed among the different age groups, and the expression of the LPL, SCD, and FABP4 genes was higher in the 1.5-year-old group. The ileum microbiota diversity was higher in the 1.5-year-old group, the Romboutsia abundance ratio was significantly higher in the 1.5-year-old group (p < 0.05), and there was a significant positive correlation with oleic acid (C18:1n9c) (p < 0.05). In conclusion, the content of beneficial fatty acids in the longissimus dorsi muscle and leg muscle of Tibetan sheep was higher at 1.5 years of age, and the best slaughter age was 1.5 years. This study provides a reference for in-depth research on the mechanism of the influence of the gut microbiota on meat quality and related regulation.

An overview of the potential application of chitosan in meat and meat products

Chitosan is considered the second most ubiquitous polysaccharide next to cellulose. It has gained prominence in various industries including biomedicine, textile, pharmaceutical, cosmetic, and notably, the food industry over the last few decades. The polymer's continual attention within the food industry can be attributed to the increasing popularity of greener means of packaging and demand for foods incorporated with natural alternatives instead of synthetic additives. Its antioxidant, antimicrobial, and film-forming abilities reinforced by the polymer's biocompatible, biodegradable, and nontoxic nature have fostered its usage in food packaging and preservation. Microbial activity and lipid oxidation significantly influence the shelf-life of meat, resulting in unfavorable changes in nutritional and sensory properties during storage. In this review, the scientific studies published in recent years regarding potential applications of chitosan in meat products; and their effects on shelf-life extension and sensory properties are discussed. The utilization of chitosan in the form of films, coatings, and additives in meat products has supported the extension of shelf-life while inducing a positive impact on their organoleptic properties. The nature of chitosan and its compatibility with various materials make it an ideal biopolymer to be used in novel arenas of food technology.

Concentration of lipids, cholesterol, and fatty acid profile in chicken breast meat affected by wooden breast myopathy frozen for up to 12 mo

The aim of this study was to examine the effects of frozen storage for 12 mo on the concentrations of lipids and cholesterol and fatty acid profile of wooden chicken breast meat. A total of 120 samples of chicken breasts were selected, according to the degree of "wooden breast" myopathy ["severe," "moderate," and "normal" (absence of myopathy)], from male chickens slaughtered at 42 d of age, from Cobb 500 strain. Part of the samples (n = 20/grade of severity) were evaluated on the day of collection and the remainder were packaged, frozen and stored at -18°C for up to 12 mo. At the beginning (collection day) and at the end of the proposed freezing period (12 mo), analyses of lipid, cholesterol, and fatty acid profile were carried out. Percentage of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids were evaluated. Meats affected by wooden breast myopathy had lower levels of PUFA that exert beneficial effects on health, such as DHA, EPA and ARA, and this profile is impaired by prolonged storage (12 mo), which results in important nutritional losses for the consumer.

Full-Length Transcriptome and Gene Expression Analysis of Different Ovis aries Adipose Tissues Reveals Transcript Variants Involved in Lipid Biosynthesis

Sheep have historically been bred globally as a vital food source. To explore the transcriptome of adipose tissue and investigate key genes regulating adipose metabolism in sheep, adipose tissue samples were obtained from F1 Dorper × Hu sheep. High-throughput sequencing libraries for second- and third-generation sequencing were constructed using extracted total RNA. Functional annotation of differentially expressed genes and isoforms facilitated the identification of key regulatory genes and isoforms associated with sheep fat metabolism. SMRT-seq generated 919,259 high-accuracy cDNA sequences after filtering. Full-length sequences were corrected using RNA-seq sequences, and 699,680 high-quality full-length non-chimeric (FLNC) reads were obtained. Upon evaluating the ratio of total lengths based on FLNC sequencing, it was determined that 36,909 out of 56,316 multiple-exon isoforms met the criteria for full-length status. This indicates the identification of 330,375 full-length FLNC transcripts among the 370,114 multiple-exon FLNC transcripts. By comparing the reference genomes, 60,276 loci and 111,302 isoforms were identified. In addition, 43,423 new genes and 44,563 new isoforms were identified. The results identified 185 (3198), 394 (3592), and 83 (3286) differentially expressed genes (transcripts) between tail and subcutaneous, tail and visceral, and subcutaneous and visceral adipose tissues, respectively. Functional annotation and pathway analysis revealed the following observations. (1) Among the differentially expressed genes (DEGs) of TF and SF tissues, the downregulation of ACADL, ACSL6, and NC_056060.1.2536 was observed in SF, while FFAR4 exhibited upregulation. (2) Among the DEGs of TF and VF tissues, expressions of ACADL, ACSL6, COL1A1, COL1A2, and SCD were downregulated in VF, with upregulation of FFAR4. (3) Among SF and VF expressions of COL1A1, COL1A2, and NC_056060.1.2536 were downregulated in VF. Specific differentially expressed genes (ACADL, ACSL6, COL1A1, COL1A2, FFAR4, NC_056060.1.2536, and SCD) and transcripts (NC_056066.1.1866.16 and NC_056066.1.1866.22) were identified as relevant to fat metabolism. These results provide a dataset for further verification of the regulatory pathway associated with fat metabolism in sheep.

Supplementation of chestnut tannins in diets can improve meat quality and antioxidative capability in Hu lambs

Chestnut tannins (CNT), as a source of hydrolyzable tannins, positively affect the antioxidant status of livestock. In the current study, 90 male Hu lambs were used to investigate the effect of dietary CNT intake on growth performance, nutrient digestibility, meat quality and oxidative stability, rumen microbial, and the transcriptomes of muscle and liver. A completely randomized design with three CNT intake levels (0, 0.3%, and 0.6%) was used. Rumen microbial and nutrient digestibility were not significantly altered by CNT intake. Diets with 0.3% CNT intake significantly reduced the shear force, yellowness at 24 h, and C20:2 polyunsaturated fatty acids of lamb meat and malondialdehyde in serum and longissimus thoracis (LT) muscle. Meanwhile, the 0.3% CNT diet significantly increased average daily gain during the 1- 21 days and 64- 90 days, dry matter intake during the 1- 21 days, the slaughter weight, and liver index of lambs. The 0.3% CNT diet significantly increased C26:0 saturated fatty acids, total antioxidant capacity, glutathione peroxidase, superoxide dismutase, and catalase in LT muscle. The meat shelf life of 0.3% CNT and 0.6% CNT groups was prolonged by 8.7 h and 5.4 h, respectively. Transcriptomic analysis revealed that CNT supplementation can induce the expression of antioxidant enzyme gene (CAT, SOD1), and the differentially expressed genes were mainly involved in antioxidant activity, transferase activity, and adenosine triphosphate binding. These results suggest that 0.3% CNT intake can relieve the oxidative stress of lambs, and improve the stability of meat color and meat tenderness, due to the enhanced antioxidative capacity.

Effects of Dam and Sire Breeds on Lamb Carcass Quality and Composition in Pasture-Based Systems

This study explored the impacts of sire and dam breed on carcass quality and composition in a pasture-based system and the use of DXA to rapidly rank carcasses for leanness. Southdown (SD) and Suffolk (SF) ewes were mated to Texel (TX) or SD rams to produce seventy-nine lambs. Lambs were raised on pasture-based systems with limited grain supplementation. Lamb birth weight was greater (p < 0.01) for TX, regardless of dam breed. Lambing rate was lower (p < 0.01) for SD than SF ewes. Circulating myostatin concentrations were greater (p < 0.05) on d 42 than d 75 or d 110 but did not differ by sire breed. Texel-sired lambs had greater (p < 0.01) carcass weight, ribeye area and quality grade compared to SD-sired. Total and primal fat mass as predicted from DXA was higher (p < 0.05) in carcasses from SD than TX sires. Muscles from TX lambs had greater (p < 0.05) polyunsaturated fatty acid (PUFA) composition than SD-sired. Shear force values were influenced (p < 0.01) by dam breed, muscle cut and postmortem age but not by sire breed. The use of TX sires in pasture-based systems improved carcass leanness and muscle PUFA concentrations without altering tenderness.

Sustainable utilization of unsaleable walnut kernel in substitution for corn grain in the diet of fattening lambs improves growth performance and meat quality

As a cost-effective typical co-product of walnut processing; this study aimed to investigate the effects of feeding poor quality, unsaleable walnut kernel, also known as wasted walnut (WW) kernel, on growth performance, carcass characteristics, meat quality and fatty acid (FA) composition of fattening lambs. The experiment was conducted using 24 fattening lambs (27 ±1.07 kg initial BW) assigned to two total mixed concentrate-based diets, over a 80-day experimental period on a completely randomized design. Dietary treatments were: 1) WW (10% WW), and 2) CON (without WW). Average daily and total gain, and final weight increased with WW inclusion (P < 0.05). Also, a significant enhancement in feed conversion ratio (P < 0.05) and carcass cooler shrink loss (P = 0.03) were observed by feeding WW. Dry matter intake (DMI) was not influenced by feeding WW as did carcass prime cuts, meat, bone and fat-tail; however, the backfat thickness was increased (P = 0.01). WW inclusion reduced cholesterol and increased protein load in muscle tissue (P ≤ 0.05). Moreover, this inclusion led to higher concentration of vaccenic acid (VA), conjugated linoleic acid (CLA) and C20 polyunsaturated FAs (PUFA), total n3 and n6 PUFA in muscle and fat-tail (P ≤ 0.05). Due to enhanced animal performance, also chemical and FA composition of muscle and adipose tissue, WW can be included in fattening lamb diets as a rich source of protein and PUFA.

Functional analysis of differentially expressed circular RNAs in sheep subcutaneous fat

BACKGROUND

Circular RNAs (circRNAs), as important non-coding RNAs (ncRNAs), are involved in many biological activities. However, the exact chemical mechanism behind fat accumulation is unknown. In this paper, we obtained the expression profiles of circRNAs using high-throughput sequencing and investigated their differential expression in subcutaneous fat tissue of Duolang and Small Tail Han sheep.

RESULTS

From the transcriptomic analysis, 141 differentially expressed circRNAs were identified, comprising 61 up-regulated circRNAs and 80 down-regulated circRNAs. These host genes were primarily enriched in the MAPK and AMPK signaling pathways which is closely associated with fat deposition regulation. We identified circRNA812, circRNA91, and circRNA388 as vital genes in fat deposition by miRNA-circRNA target gene prediction. The functional annotation results of target genes of key circRNAs showed that the signaling pathways mainly included PI3K-Akt and AMPK. We constructed the competing endogenous RNA (ceRNA) regulatory network to study the role of circRNAs in sheep lipid deposition, and circRNA812, circRNA91, and circRNA388 can adsorb more miRNAs. NC_040253.1_5757, as the source of miRNA response element (MRE) among the three, may play an important role during the process of sheep fat deposition.

CONCLUSIONS

Our study gives a systematic examination of the circRNA profiles expressed in sheep subcutaneous fat. These results from this study provide some new basis for understanding circRNA function and sheep fat metabolism.

Combining sheep and beef cattle in a pasture-based system minorly influenced muscle and fat colour and dorsal fat firmness but increased fat skatole content in lambs

A recent long-term system-level experiment, using grassland-based organic systems established as separate farmlets, showed that combining sheep and beef cattle within a mixed (MIX) system promoted self-sufficient production of grass-fed meat and improved economic and environmental performance in the sheep enterprise compared to a sheep-only (SH) system. In the present study, we used all male lambs produced over the first year in this experiment to evaluate the effect of this farming practice on some lamb carcass and meat sensory quality traits. Lambing took place at the end of February and lambs were pasture-fed from 1 month of age on average until slaughter, unless they were not ready for slaughter at 3-4 weeks before the start of the mating period in October, in which case they were finished indoors on a concentrate-based diet. All MIX lambs (n = 33) were finished at pasture. One SH lamb (out of a total of 85) had to be finished indoors with a concentrate-based diet. MIX lambs had a higher growth rate than SH lambs (P < 0.001), resulting in a lower lamb age at slaughter in MIX than in SH (150 vs 173 days, P < 0.001). Carcass weight and degree of fatness, kidney fat weight and dorsal fat thickness did not differ between systems. Kidney fat skatole concentration was higher in MIX than in SH (median value reaching 0.15 µg/g liquid fat and 0.11 µg/g liquid fat in MIX and SH, respectively, P < 0.05). This was most likely due to MIX lambs being slaughtered at a younger age and therefore eating younger grass. There were minor differences between MIX and SH lambs in dorsal fat firmness and in colour coordinates of longissimus thoracis et lumborum muscle. We conclude that while combining sheep and beef cattle within a mixed system offers advantages in terms of self-sufficient production of grass-fed meat and system economic and environmental performance, it could come at a cost to lamb flavour.

Probiotics Increase Intramuscular Fat and Improve the Composition of Fatty Acids in Sunit Sheep through the Adenosine 5'-Monophosphate-Activated Protein Kinase (AMPK) Signaling Pathway

This experiment aims to investigate the impact of probiotic feed on growth performance, carcass traits, plasma lipid biochemical parameters, intramuscular fat and triglyceride content, fatty acid composition, mRNA expression levels of genes related to lipid metabolism, and the activity of the enzyme in Sunit sheep. In this experiment, 12 of 96 randomly selected Sunit sheep were assigned to receive the basic diet or the basic diet supplemented with probiotics. The results showed that supplementation with probiotics significantly increased the loin eye area, and decreased plasma triglycerides and free fatty acids, increasing the content of intramuscular fat and triglycerides in the muscle and improving the composition of the fatty acids. The inclusion of probiotics in the diet reduced the expression of adenosine 5'-monophosphate-activated protein kinase alpha 2 (AMPKα2) mRNA and carnitine palmitoyltransferase 1B (CPT1B) mRNA, while increasing the expression of acetyl-CoA carboxylase alpha (ACCα) mRNA, sterol regulatory element-binding protein-1c (SREBP-1c) mRNA, fatty acid synthase mRNA, and stearoyl-CoA desaturase 1 mRNA. The results of this study indicate that supplementation with probiotics can regulate fat deposition and improves the composition of fatty acids in Sunit sheep through the signaling pathways AMPK-ACC-CPT1B and AMPK-SREBP-1c. This regulatory mechanism leads to an increase in intramuscular fat content, a restructuring of muscle composition of the fatty acids, and an enhancement of the nutritional value of meat. These findings contribute to a better understanding of the food science of animal resources and provide valuable references for the production of meat of higher nutritional value.

Feeding regimens affecting carcass and quality attributes of sheep and goat meat - A comprehensive review

Sheep and goats can efficiently convert low quality forage into high-quality meat which contains specific nutrients and quality traits. Carcass traits and quality attributes of sheep and goat meat depend upon several factors and one of most effective strategies amongst these is feeding regimens. In this review, the major aspects of feeding regimens affecting growth rate, carcass traits and quality attributes of sheep and goat meat are thoroughly discussed, with a particular focus on physical-chemical composition, flavor profile, and fatty acid (FA) profile. Grazing lambs and kids receiving concentrate or under stall-feeding systems had greater average daily gain and carcass yield compared with animals reared on pasture only. However, growth rate was higher in lambs/kids grazing on pastures of improved quality. Moreover, the meat of grazing lambs receiving concentrate had more intense flavor, intramuscular fat (IMF) content, and unhealthy FA composition, but comparable color, tenderness, juiciness, and protein content compared to that of lambs grazed on grass only. In contrast, meat of concentrate-fed lambs had more intense color, greater tenderness and juiciness, IMF and protein contents, and lower flavor linked to meat. Additionally, the meat of kids grazed on concentrate supplementation had higher color coordinates, tenderness, IMF content and unhealthy FA composition, whereas juiciness and flavor protein content were similar. In contrast, kids with concentrate supplementation had superior color coordinates, juiciness, IMF content and unhealthy FA composition, but lower tenderness and flavor intensity compared to pasture-grazed kids. Thus, indoor-finished or supplemented grazing sheep/goats had higher growth rate and carcass quality, higher IMF content and unhealthy FA composition compared to animals grazed on grass only. Finally, supplementation with concentrate increased flavor intensity in lamb meat, and improved color and tenderness in kid meat, whereas indoor-fed sheep/goats had improved color and juiciness as well as reduced flavor compared to pasture-grazed animals.

Comparative Analysis of the Pre-Parturition and Post-Parturition Genital Tract Microbiota in Plateau Bangor Sewa Sheep

(1) Background: Bangor Sewa sheep are an economically significant livestock species on the plateau. The roles of microbiota in reproduction are complex and critical for animal health. But little is known currently about the microbiome of plateau Bangor Sewa sheep. The purpose of this study was to discover the changes in the genital tract microbiota of pre- and post-partum Bangor Sewa sheep. (2) Methods: Samples from the birth canal were obtained for 16S rRNA sequencing, three days before and after delivery, respectively. (3) Results: The results showed that there was a noticeable difference in three phyla and 74 genera between the pre- and post-parturition groups in the microbiota of Bangor Sewa sheep. The changes included a decrease in the abundance of genera related to health (unclassified_Cellulomonadaceae, Cellulomonas, Fibrobacti, Flavobacterium, Eubacterium_ventriosum_group, Acetitomaculum, Aeromicrobium, Dietzia, Romboutsia, Ruminococcus, etc.) and an increased abundance of negatively related genera (Nocardioides, unclassified_Clostridia, Sphingobacteriaceae, unclassified_Ruminococcaceae, Prevotellaceae_UCG_004, Micromonospora, Streptococcus, Facklamia, Bosea, etc.) spp. (4) Conclusions: Microbes can serve as indicators of the physical state of Bangor Sewa sheep. These findings laid the foundation for deciphering the effects of microbial changes during birth on the reproductive health of plateau Bangor Sewa sheep.

Interactions of rumen microbiota and metabolites with meat quality-related genes to regulate meat quality and flavor of Tibetan sheep under nutrient stress in the cold season

AIM

The meat of Tibetan sheep has a unique flavor, delicious taste, and superior nutritional value. However, the change of grass will lead to a change in meat quality. This study aimed to explore the potential regulatory mechanisms of microbial metabolites with respect to meat quality traits of Tibetan sheep under nutrient stress in the cold season.

METHODS AND RESULTS

We determined and analyzed the longissimus dorsi quality, fatty acid composition, expression of genes, and rumen microbial metabolites of Tibetan sheep in cold and warm seasons. The shear force was decreased (P < .05), the meat color a*24 h value was increased (P < .05), and the contents of crude fat (EE) and protein (CP) were decreased in the cold season. Polyunsaturated fatty acids (PUFAs)-linoleic acid and docosahexaenoic acid increased significantly in the cold season (P < .05). The expressions of meat quality genes MC4R, CAPN1, H-FABP, and LPL were significantly higher in the warm season (P < .05), and the CAST gene was significantly expressed in the cold season (P < .01). The different microbial metabolites of Tibetan sheep in the cold and warm seasons were mainly involved in amino acid metabolism, lipid metabolism, and digestive system pathway, and there was some correlation between microbiota and meat quality traits. There are similarities between microbial metabolites enriched in the lipid metabolism pathway and muscle metabolites.

CONCLUSION

Under nutritional stress in the cold season, the muscle tenderness of Tibetan sheep was improved, and the fat deposition capacity was weakened, but the levels of beneficial fatty acids were higher than those in the warm season, which was more conducive to healthy eating.

Association of branched-chain fatty acids with metabolic syndrome: a systematic review and meta-analysis of observational studies

Background: branched-chain fatty acids (BCFAs) have recently emerged as a group of functional fatty acids that are widely distributed in various foodstuffs, including dairy products, ruminant meat products, and fermented foods. Several studies have investigated the differences in the levels of BCFAs among individuals with varying risks of metabolic syndrome (MetS). In this study, we conducted a meta-analysis to explore the relationship between BCFAs and MetS, and to assess the feasibility of BCFAs as potential biomarkers for diagnosing MetS. Methods: in accordance with the PRISMA guidelines, we conducted a systematic literature search on PubMed, Embase, and the Cochrane Library up to March 2023. Both longitudinal and cross-sectional studies were included. The quality of the longitudinal and cross-sectional studies was evaluated using the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) criteria, respectively. Heterogeneity detection and sensitivity analysis of the included research literature were carried out using R 4.2.1 software with a random-effects model. Results: Our meta-analysis included 685 participants and revealed a significant negative correlation between the endogenous BCFAs (serum BCFAs and adipose tissue BCFAs) and the risk of developing MetS, with lower BCFA levels found in individuals at a high risk of MetS (WMD: -0.11%, 95% CI: [-0.12, -0.09] %, P < 0.0001). However, there was no difference in fecal BCFAs among different MetS risk groups (SMD: -0.36, 95% CI: [-1.32, 0.61], P = 0.4686). Conclusion: our study provides insights into the relationship between BCFAs and the risk of developing MetS, and lays the groundwork for the development of novel biomarkers for diagnosing MetS in the future.

Monomethyl branched-chain fatty acids-a pearl dropped in the ocean

As an emerging group of bioactive fatty acids, monomethyl branched-chain fatty acids (mmBCFAs) have sparked the interest of many researchers both domestically and internationally. In addition to documenting the importance of mmBCFAs for growth and development, there is increasing evidence that mmBCFAs are highly correlated with obesity and insulin resistance. According to previous pharmacological investigations, mmBCFAs also exhibit anti-inflammatory effects and anticancer properties. This review summarized the distribution of mmBCFAs, which are widely found in dairy products, ruminants, fish, and fermented foods. Besides, we discuss the biosynthesis pathway in different species and detection methods of mmBCFAs. With the hope to unveil their mechanisms of action, we recapitulated detailed the nutrition and health benefits of mmBCFAs. Furthermore, this study provides a thorough, critical overview of the current state of the art, upcoming difficulties, and trends in mmBCFAs.

Associations between sheep meat intake frequency and blood plasma levels of metabolites and lipoproteins in healthy Uzbek adults

INTRODUCTION

Uzbekistan is one of the countries with the highest number of diet-related chronic diseases, which is believed to be associated with high animal fat intake. Sheep meat is high in fats (~ 5% in muscle), including saturated and monounsaturated fatty acids, and it contains nearly twice the higher amounts of n-3 polyunsaturated fatty acids and conjugated linoleic acids compared to beef. Nevertheless, sheep meat is considered health promoting by the locals in Uzbekistan and it accounts for around 1/3 of red meat intake in the country.

OBJECTIVES

The aim of this study was to apply a metabolomics approach to investigate if sheep meat intake frequency (SMIF) is associated with alterations in fasting blood plasma metabolites and lipoproteins in healthy Uzbek adults.

METHODS

The study included 263 subjects, 149 females and 114 males. For each subject a food intake questionnaire, including SMIF, was recorded and fasting blood plasma samples were collected for metabolomics. Blood plasma metabolites and lipoprotein concentrations were determined using ¹H NMR spectroscopy.

RESULTS AND CONCLUSION

The results showed that SMIF was confounded by nationality, sex, body mass index (BMI), age, intake frequency of total meat and fish in ascending order (p < 0.01). Multivariate and univariate data analyses showed differences in the levels of plasma metabolites and lipoproteins with respect to SMIF. The effect of SMIF after statistical adjustment by nationality, sex, BMI, age, intake frequency of total meat and fish decreased but remained significant. Pyruvic acid, phenylalanine, ornithine, and acetic acid remained significantly lower in the high SMIF group, whereas choline, asparagine, and dimethylglycine showed an increasing trend. Levels of cholesterol, apolipoprotein A1, as well as low- and high-density lipoprotein subfractions all displayed a decreasing trend with increased SMIF although the difference were not significant after FDR correction.

Fatty acid and oxidative shelf-life profiles of meat from lambs fed finisher diets containing Acacia mearnsii leaf-meal

Five diets containing Acacia mearnsii leaf-meal (AMLM; 0, 50, 100, 150 and 200 g/kg DM) substituted for Triticum aestivum bran were fed to lambs for 42 days. The effect of diet and retail display period on meat fatty acid (FA) composition (day 1); colour, antioxidant activity, myoglobin and lipid oxidation (day 1, 3, 5, 7 and 9); protein oxidation (1, 3 and 7 d) and instrumental tenderness (day 1, 5 and 10) were evaluated. Dietary AMLM linearly decreased (P ≤ 0.05) individual (14:0, 16:0, 18:0) and total saturated FA and increased (P ≤ 0.05) trans(t)-monounsaturated FA (MUFA) mainly t10/t11-18:1, individual and total conjugated linoleic acids, n-3 and n-6 polyunsaturated FA (PUFA) contents. The contents of cis(c)-MUFA, mainly c9-18:1, exhibited a quadratic response reaching a minimum at 50 g/kg AMLM (P ≤ 0.05). Meat antioxidant on day 9 was higher (P ≤ 0.05) for diets containing ≥100 g/kg DM AMLM compared to the other diet × retail display period interactions. Relative to the other interactions, meat redness values were lowest on day 7 and 9 for AMLM diets containing ≥150 g/kg DM (P ≤ 0.05). Dietary addition of AMLM increased (P ≤ 0.05) meat lightness and oxymyoglobin, and reduced (P ≤ 0.05) TBARS and instrumental tenderness values. However, oxymyoglobin values declined (P ≤ 0.05) over the retail display period, while lightness, metmyoglobin, TBARS and carbonyls increased (P ≤ 0.05). Results indicate that AMLM up to 200 g/kg DM in lamb finisher diets, improves meat fatty acid composition, tenderness, and lipid shelf-life.

Forage based diet as an alternative to a high concentrate diet for finishing young bulls - Effects on growth performance, greenhouse gas emissions and meat quality

Two groups of 8 individually housed young crossbred-bulls, in the finishing period, were used to test the effect of a Total Mixed Ration diet with high forage content (54% DM), low starch content (14% DM), supplemented with sunflower seeds (10% DM) (HFS) on growth performance, carcass and meat quality, fatty acid profile and carbon footprint, with reference to a conventional concentrate-based (90% DM) (Control) diet. The experiment lasted 64 days before slaughter. During the experiment, feed intake was monitored daily and live weight every 14 days. Individual CH₄ emissions were assessed at 16-days intervals, using a GreenFeed for Large Animal unit. Feed intake and feed conversion ratio were higher for HFS diet, but average daily weight gain and feeding costs were similar for the two diets. Dressing percentage was reduced with HFS diet. The HFS increased redness, yellowness and Chroma of subcutaneous fat, but did not compromise commercial value of the carcasses. Meat colour, shear force, or sensory parameters were not affected by diet. The HFS diet allowed a healthier FA profile, due to the higher proportions of 18:3n-3, t11-18:1 and c9,t11-18:2 and the lower proportion of t10-18:1. The HFS diet did not reduce the carbon footprint in the finishing period of young bulls, due to increased digestive CH₄ emissions. The results of this experiment showed that the HFS diet can be an alternative to the conventional diets used in finishing young-bulls. Although it may result in a slight reduction in animal performance, it has a strong impact on reducing dependence on inputs from outside the farm.

Estrogen-mediated oar-miR-485-5p targets PPP1R13B to regulate myoblast proliferation in sheep

Ovaries are important endocrine organs in female animals that secrete various steroid hormones, which are involved in multiple physiological functions. Estrogen, one of the hormones secreted by ovaries, is essential for the overall maintenance of muscle growth and development. However, the molecular mechanisms that affect muscle growth and development in sheep following ovariectomy remain unclear. In this study, we identified 1662 differentially expressed mRNAs (DEGs) and 40 differentially expressed miRNAs (DEMs) in sheep that underwent ovariectomy compared with those that underwent sham surgery. A total of 178 DEG-DEM pairs were negatively correlated. GO and KEGG analysis showed that PPP1R13B was involved in the PI3K-Akt signaling pathway, which was essential for muscle development. Using in vitro experiments, we examined the effect of PPP1R13B on myoblast proliferation and found that overexpression or inhibition of PPP1R13B increased or decreased the expression of myoblast proliferation markers, respectively. PPP1R13B was identified as a functional downstream target of miR-485-5p. Our results suggested that miR-485-5p promoted myoblast proliferation by regulating proliferation factors in myoblasts by targeting PPP1R13B. Notably, exogenous estradiol supplementation to myoblasts regulated the expression of oar-miR-485-5p and PPP1R13B and promoted myoblast proliferation. These results provided new insights into the molecular mechanism by which ovaries influence muscle growth and development in sheep.

Effects of Chia Seeds on Growth Performance, Carcass Traits and Fatty Acid Profile of Lamb Meat

The aim of this work was to supplement a diet with chia seeds (Salvia hispanica L.) based on the requirements of finishing lambs for meat, and to analyze biometric parameters and fatty acid profiles in meat. Eighteen male Rambouillet lambs with a bodyweight of 25 kg were used. Animals were kept in individual pens with water and feed provided ad libitum. Three finishing diets were designed with the inclusion of 0, 50 and 100 g dry matter chia seeds and divided among the animals (n = 6). The experimental period lasted 60 days. The weights of the individual lambs were recorded every 14 days. At the end of the experiment, the animals were slaughtered and the weights of the hot carcasses and non-meat components were registered. In addition, an analysis of the fatty acid composition was carried out in the muscles (Longissimus thoracis). The total weight gain and average daily gain displayed significant differences (p < 0.05). Initial and final bodyweights, such as the dry matter intake, did not display differences. The fatty acid profile of the meat tended to decrease the SFA (stearic acid) and increase MUFA (oleic acid) (p < 0.0001) when chia seeds were added to the lamb diets. In conclusion, chia seed supplementation did not increase meat production or other biometric parameters; however, it modified the fatty acid profile in L. thoracis.

Rumen microbial-driven metabolite from grazing lambs potentially regulates body fatty acid metabolism by lipid-related genes in liver

BACKGROUND

Lipid metabolism differs significantly between grazing and stall-feeding lambs, affecting the quality of livestock products. As two critical organs of lipid metabolism, the differences between feeding patterns on rumen and liver metabolism remain unclear. In this study, 16S rRNA, metagenomics, transcriptomics, and untargeted metabolomics were utilized to investigate the key rumen microorganisms and metabolites, as well as liver genes and metabolites associated with fatty acid metabolism under indoor feeding (F) and grazing (G).

RESULTS

Compared with grazing, indoor feeding increased ruminal propionate content. Using metagenome sequencing in combination with 16S rRNA amplicon sequencing, the results showed that the abundance of propionate-producing Succiniclasticum and hydrogenating bacteria Tenericutes was enriched in the F group. For rumen metabolism, grazing caused up-regulation of EPA, DHA and oleic acid and down-regulation of decanoic acid, as well as, screening for 2-ketobutyric acid as a vital differential metabolite, which was enriched in the propionate metabolism pathway. In the liver, indoor feeding increased 3-hydroxypropanoate and citric acid content, causing changes in propionate metabolism and citrate cycle, while decreasing the ETA content. Then, the liver transcriptome revealed that 11 lipid-related genes were differentially expressed in the two feeding patterns. Correlation analysis showed that the expression of CYP4A6, FADS1, FADS2, ALDH6A1 and CYP2C23 was significantly associated with the propionate metabolism process, suggesting that propionate metabolism may be an important factor mediating the hepatic lipid metabolism. Besides, the unsaturated fatty acids in muscle, rumen and liver also had a close correlation.

CONCLUSIONS

Overall, our data demonstrated that rumen microbial-driven metabolite from grazing lambs potentially regulates multiple hepatic lipid-related genes, ultimately affecting body fatty acid metabolism.

Fatty Acid and Multi-Isotopic Analysis (C, H, N, O) as a Tool to Differentiate and Valorise the Djebel Lamb from the Mountainous Region of Tunisia

The objective of this study was to distinguish between the Tunisian Djebel lamb meat and meat from typical Tunisian production systems (PSs) through the fatty acids (FAs) profile and the stable isotope ratio analysis (SIRA). Thirty-five lambs from three different regions and PSs (D = Djebel, B = Bou-Rebiaa, and O = Ouesslatia) were considered for this purpose. The results demonstrated that the PS and the geographic origin strongly influenced the FA profile of lamb meat. It was possible to discriminate between the Djebel lamb meat and the rest of the dataset thanks to the quantification of the conjugated linoleic acids (CLA) and the branched chain FAs. Moreover, statistically different concentrations of saturated, monounsaturated and polyunsaturated FAs and a different n-6/n-3 ratio were found for grazing (D and BR) and indoor (O) lambs, making it possible to discriminate between them. As for the stable isotope ratio analysis, all parameters made it possible to distinguish among the three groups, primarily on the basis of the dietary regimen (δ(¹³C) and δ(¹⁵N)) and breeding area (δ(¹⁸O) and δ(²H)).

Metabolome and microbiome analysis revealed the effect mechanism of different feeding modes on the meat quality of Black Tibetan sheep

Introduction

Black Tibetan sheep is one of the primitive sheep breeds in China that is famous for its great eating quality and nutrient value but with little attention to the relationship between feeding regimes and rumen metabolome along with its impact on the muscle metabolism and meat quality.

Methods

This study applies metabolomics-based analyses of muscles and 16S rDNA-based sequencing of rumen fluid to examine how feeding regimes influence the composition of rumen microbiota, muscle metabolism and ultimately the quality of meat from Black Tibetan sheep. Twenty-seven rams were randomly assigned to either indoor feeding conditions (SG, n = 9), pasture grazing with indoor feeding conditions (BG, n = 9) or pasture grazing conditions (CG, n = 9) for 120 days.

Results

The results showed that, compared with BG and CG, SG improved the quality of Black Tibetan sheep mutton by preventing a decline in pH and increasing fat deposition to enhance the color, tenderness and water holding capacity (WHC) of the Longissimus lumborum (LL). Metabolomics and correlation analyses further indicated that the feeding regimes primarily altered amino acid, lipid and carbohydrate metabolism in muscles, thereby influencing the amino acid (AA) and fatty acid (FA) levels as well as the color, tenderness and WHC of the LL. Furthermore, SG increased the abundance of Christensenellaceae R-7 group, [Eubacterium] coprostanoligenes group, Methanobrevibacter, Ruminococcus 2 and Quinella, decreased the abundance of Lactobacillus, Prevotella 1 and Rikenellaceae RC9 gut group, and showed a tendency to decrease the abundance of Succinivibrio and Selenomonas 1. Interestingly, all of these microorganisms participated in the deposition of AAs and FAs and modified the levels of different metabolites involved in the regulation of meat quality (maltotriose, pyruvate, L-ascorbic acid, chenodeoxycholate, D-glucose 6-phosphate, glutathione, etc.).

Discussion

Overall, the results suggest that feeding Black Tibetan sheep indoors with composite forage diet was beneficial to improve the mouthfeel of meat, its color and its nutritional value by altering the abundance of rumen bacteria which influenced muscle metabolism.

Effect of Different Heat Treatments on the Quality and Flavor Compounds of Black Tibetan Sheep Meat by HS-GC-IMS Coupled with Multivariate Analysis

There are limited reports about the effect of different heat treatments on the quality and flavor of Black Tibetan sheep meat. The current study examined the effect of pan-frying, deep-frying, baking, and boiling treatment on the quality of Black Tibetan sheep meat; the amino acid, fatty acid, and volatile flavor compounds (VFCs) were investigated by a texture analyzer, ultra-high-performance liquid chromatography (UHPLC), gas chromatography (GC), and headspace-gas chromatography-ion mobility (HS-GC-IMS). The key VFCs were identified through orthogonal partial least squares discrimination analysis (OPLS-DA), and variable importance projection (VIP) values. In addition, Pearson’s correlations between meat quality parameters and key VFCs were examined. The sensory scores, including texture, color, and appearance, of baked and pan-fried meat were higher than those of deep-fried and boiled meat. The protein (40.47%) and amino acid (62.93 µmol/g) contents were the highest in pan-fried meat (p < 0.05). Additionally, it contained the highest amounts of monounsaturated and polyunsaturated fatty acids, such as oleic, linoleic, and α-linolenic acids (p < 0.05). Meanwhile, pan-fried and deep-fried meat had higher amounts of VFCs than baked meat. The OPLS-DA similarity and fingerprinting analyses revealed significant differences between the three heat treatment methods. Aldehydes were the key aroma compounds in pan-fried meat. Importantly, 3-methylbutyraldehyde and 2-heptanone contents were positively correlated with eicosenoic, oleic, isooleic, linoleic, α-Linolenic, and eicosadiene acids (p < 0.05). To sum up, pan-fried Black Tibetan sheep meat had the best edible, nutritional, and flavor quality.

Effects of Sheep Sires on Muscle Fiber Characteristics, Fatty Acid Composition and Volatile Flavor Compounds in F1 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.

Characteristics of growth, carcass and meat quality of sheep with different feed efficiency phenotypes

The objective was to evaluate the performance, carcass and meat quality of 40 lambs classified by RFI (residual feed intake) and RIG (residual intake and gain). Dry matter intake (DMI) was recorded to calculate the RFI and RIG, classified as efficient, moderately or inefficient. After the confinement period, they were slaughtered and the carcass and meat quality were determined. The efficient animals had DMI scores of 0.700 RFI and 0.400 kg/d RIG, lower than the inefficient ones with similar weight gain. The RFI efficient animals showed greater shear force, without effect in the RIG classification. In general, the variables analyzed were not influenced by RFI or RIG. Efficiency measures do not affect the carcass and meat quality of sheep, but they do have the advantage of identifying animals with lower feed consumption, making the system more efficient. However, as the dataset is limited to fully assess the effects, this manuscript can be used as preliminary results for future studies.

Engineering Yarrowia lipolytica to produce nutritional fatty acids: Current status and future perspectives

Due to their vital physiological functions, nutritional fatty acids have great potential as nutraceutical food supplements for preventing an array of diseases such as inflammation, depression, arthritis, osteoporosis, diabetes and cancer. Microbial biosynthesis of fatty acids follows the trend of sustainable development, as it enables green, environmentally friendly and efficient production. As a natural oleaginous yeast, Yarrowia lipolytica is especially well-suited for the production of fatty acids. Moreover, it has a variety of genetic engineering tools and novel metabolic engineering strategies that make it a robust workhorse for the production of an array of value-added products. In this review, we summarize recent advances in metabolic engineering strategies for accumulating nutritional fatty acids in Y. lipolytica, including conjugated fatty acids and polyunsaturated fatty acids. In addition, the future prospects of nutritional fatty acid production using the Y. lipolytica platform are discussed in light of the current progress, challenges, and trends in this field. Finally, guidelines for future studies are also emphasized.

Transcript variants of long-chain acyl-CoA synthase 1 have distinct roles in sheep lipid metabolism

Mutton has recently been identified to be a consumer favorite, and intermuscular fat is the key factor in determining meat tenderness. Long-chain acyl-CoA synthetase 1 (ACSL1) is a vital subtype of the ACSL family that is involved in the synthesis of lipids from acyl-CoA and the oxidation of fatty acids. The amplification of the ACSL1 gene using rapid amplification of cDNA ends revealed that the alternative polyadenylation (APA) results in two transcripts of the ACSL1 gene. Exon 18 had premature termination, resulting in a shorter CDS region. In this study, the existence of two transcripts of varying lengths translated normally and designated ACSL1-a and ACSL1-b was confirmed. Overexpression of ACSL1-a can promote the synthesis of an intracellular diglyceride, while ACSL1-b can promote triglyceride synthesis. The transfection of ACSL1 shRNA knocks down both the transcripts, the triglyceride content was significantly reduced after differentiation and induction; and lipidome sequencing results exhibited a significant decrease in 14-22 carbon triglyceride metabolites. The results of the present study indicated that the ACSL1 gene played a crucial role in the synthesis of triglycerides. Furthermore, the two transcripts involved in various interactions in the triglyceride synthesis process may be the topic of interest for future research and provide a more theoretical basis for sheep breeding.

Fatty Acid and Micronutrient Profile of Longissimus Lumborum from Red Angus and Red Angus x Akaushi Cattle Finished on Grass or Grain

Cattle diet and breed modify the nutritional profile of beef. The objective of this study was to compare the fatty acid (FA) and micronutrient profiles of Red Angus (RA) and RA x Akaushi (AK) crossbreed steers fed either a grass or grain diet. This two-year study randomly assigned steers to the diets using a 2 × 2 factorial experiment. FAs and micronutrients were analyzed. Diet effect was the strongest with grass-finished beef being higher in n-3 polyunsaturated FAs (p < 0.001), conjugated linoleic acid (p < 0.05), vaccenic acid (p < 0.05), iron (p < 0.001), and vitamin E (p < 0.001) compared to grain-finished beef. Breed effects were observed for lauric and myristic acids (p < 0.05), selenium (p < 0.05), and zinc (p < 0.01) with AK containing more of these compounds than RA. Diet × breed effects were non-existent. These results indicate that diet has a stronger influence than breed on modifying the nutritional profile of beef. Because of a more favorable FA and antioxidant profile, consumption of grass-finished beef could benefit human health.

Fatty acid profile, secondary compounds and antioxidant activities in the fresh forage, hay and silage of sainfoin (Onobrychis viciifolia) and sulla (Hedysarum coronarium)

BACKGROUND

Sainfoin (Onobrychis viciifolia) and sulla (Hedysarum coronarium) are forage legumes usually preserved to optimize their utilization as feedstuffs. However, the method of preservation modifies the chemical composition differently in both legume species. Secondary compounds (such as proanthocyanidins, fatty acids, carotenoids and tocopherols) present in forages affect the quality of animal products. Therefore, the effect of preservation on the contents of secondary compounds should be investigated. Accoridngly, samples of sainfoin and sulla were directly freeze-dried (fresh), dried at ambient temperature (hay) and vacuum-packaged for 82 days (silage).

RESULTS

In both legumes, the total fatty acid and C18:3 n-3 contents decreased and C16:0 increased with preservation (P < 0.001), with a greater effect for the hays than for the silages. For both legumes, the lutein, neoxanthin and violaxanthin contents decreased to a greater extent in the silages than in the hays (P < 0.001). Both hays exhibited the lowest β-carotene concentrations (P < 0.001). The α-tocopherol contents decreased in hays, but not in silages, compared to the fresh forages of both legumes (P < 0.001). The antioxidant activities were lower in the silages than in the hays and fresh forages (P < 0.001) and were very strongly related to the contents of polyphenols and proanthocyanidins (P < 0.001).

CONCLUSION

Haymaking affected the fatty acid, carotenoid and α-tocopherol contents to a greater extent but had a lesser effect on the antioxidant activities than silage-making, which were very strongly related to their contents of polyphenols and proanthocyanidins. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Influence of Dietary Algae Meal on Lipid Oxidation and Volatile Profile of Meat from Lambs with Competent Reticular Groove Reflex

Dietary lipid sources influence intramuscular fatty acid composition, which in turn may affect the volatile profile of meat. The aim of this work was to investigate the effects of marine algae supplementation (Aurantiochytrium limacinum) on volatile compounds of cooked lamb meat. Forty-eight lambs with 42 days of age were divided into three groups: lambs fed a conventional diet without algae meal supplementation (NOALG), lambs with competent reticular groove reflex (RGR) fed the same diet supplemented with 2.5% marine algae meal mixed in the concentrate (ALGCON), and lambs with competent RGR, receiving the same diet and fed with 2.5% marine algae meal in a milk replacer to bypass the rumen (ALGMILK). Lipid and protein oxidation in raw meat was assessed and volatile compounds in grilled meat were determined. The highest and lowest lipid oxidations were observed in the ALGMILK and NOALG groups, respectively. Protein oxidation was unaffected. Out of 56 identified compounds, 12 volatiles significantly increased in both algae groups and 6 of them exclusively in the ALGCON treatment. Algae meal supplementation and its form of administration, either protected or not from rumen degradation, are important factors to consider in lipid oxidation and the aromatic profile of lamb meat.

Improving the functional value of meat quality by feeding with protected fat supplementation in Morkaraman lambs

This study investigated the effect of feeding different levels of protected fat (calcium soaps of tallow) on fattening performance, carcass characteristics, meat quality, fatty acid composition of Longissimus Thoracis (LT) muscle and economic evaluation of 45 fat-tailed Morkaraman male lambs. The lambs were randomly divided into three groups including a control diet without protected fat (CON), supplemented with 2% protected fat (group PF2), and supplemented with 4% protected fat (group PF4) during the fattening period. Eight lambs randomly selected from each group were slaughtered to determine carcass characteristics and meat quality. Supplementing protected fat significantly improved the fattening performance and carcass characteristics (p<0.05). The groups were similar in terms of pH, colour, ether extract, dry matter and sensory evaluations, except for the crude protein of group PF2. Myristic acid and stearic acid (p<0.05), which are saturated fatty acids (SFA), were decreased with the supplementation of protected fat, while palmitic acid was increased (p<0.01). The fattening with protected fat had a highly significant positive effect on important unsaturated fatty acids such as oleic acid (p<0.01) and resulted in an increase of approximately 91% in the conjugated linoleic acid (CLA) (p<0.05). SFA was significantly decreased, and health indicators were improved (p<0.01). In conclusion, the supplementation of protected fat had a positive effect on fattening performance, carcass traits, chemical, sensory properties and economic evaluation.

Evaluation of Mutton Quality Characteristics of Dongxiang Tribute Sheep Based on Membership Function and Gas Chromatography and Ion Mobility Spectrometry

Dongxiang tribute sheep have a history of use in food dishes such as "Dongxiang Handgrip," which dates back hundreds of years and is a favorite halal food in northwestern China. However, little is known about the mutton quality characteristics of Dongxiang tribute sheep. Here, we measured the sensory characteristics, nutritional quality, and flavor substances to comprehensively evaluate the mutton quality characteristics of these sheep. The mutton qualities of Dongxiang tribute, Tibetan, Ujumqin, and Hu sheep were comprehensively evaluated by membership function. Subsequently, the volatile components in mutton samples from 30 Dongxiang tribute sheep were detected via gas chromatography and ion mobility spectrometry (GC-IMS), and their fingerprints were established. The result of meat quality revealed that the shear force, the contents of protein, essential amino acid (EAA), non-essential amino acid (NEAA), and n-6/n-3 ratio of Dongxiang tribute mutton were better than the other three breeds. Membership functions were calculated for 10 physical and chemical indexes of mutton quality, and the comprehensive membership function values of the four breeds in order of highest to lowest mutton quality were Tibetan sheep (0.76) > Dongxiang tribute sheep (0.49) > Hu sheep (0.46) > Ujumqin sheep (0.33). Thirty volatile compounds were identified via GC-IMS: seven alcohols, eight aldehydes, five ketones, two esters, two phenols, one ether, one furan, one acid, two hydrocarbons, and one pyrazine. Ketones, aldehydes, and alcohols were the main volatile compounds forming the flavor of Dongxiang tribute sheep mutton. The reliability of the results was validated by PCA (principal component analysis) and similarity analyses. Our results provide reference value for consumers of mutton in China.

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.

Reconsidering Meat Intake and Human Health: A Review of Current Research

Meat consumption is gradually increasing and its impact on health has attracted widespread attention, resulting in epidemiological studies proposing a reduction in meat and processed meat intake. This review briefly summarizes recent advances in understanding the effects of meat or processed meat on human health, as well as the underlying mechanisms. Meat consumption varies widely among individuals, populations, and regions, with higher consumption in developed countries than in developing countries. However, increasing meat consumption may not be the main cause of increasing incidence of chronic disease, since the development of chronic disease is a complex physiological process that involves many factors, including excessive total energy intake and changes in food digestion processes, gut microbiota composition, and liver metabolism. In comparison, unhealthy dietary habits and a sedentary lifestyle with decreasing energy expenditure are factors more worthy of reflection. Meat and meat products provide high-value protein and many key essential micronutrients. In short, as long as excessive intake and overprocessing of meats are avoided, meat remains an indispensable source of nutrition for human health.

Breed dependent regulatory mechanisms of beneficial and non-beneficial fatty acid profiles in subcutaneous adipose tissue in cattle with divergent feed efficiency

The current study aimed to determine whether breed and feed efficiency affect the molecular mechanisms regulating beneficial and non-beneficial fatty acid profiles in subcutaneous adipose tissue of beef steers. Fatty acid profiling and RNA-Seq based transcriptome analysis were performed on subcutaneous adipose tissues collected from beef steers with three divergent breeds (Angus, ANG, n = 47; Charolais, CHAR, n = 48; Kinsella Composite, KC, n = 48) and different residual feed intake (RFI, a measure of feed efficiency). The comparison of fatty acid profiles showed that KC had higher beneficial FAs compared to the other two breeds. Distinct FA profiles between H-RFIfat and L-RFIfat steers was more obvious for KC steers, where H-RFIfat steers tended to have higher proportion of healthy FAs and lower proportion of the unhealthy FAs. A higher number of differentially expressed (DE) genes were observed for KC steers, whereas ANG and CHAR steers had a lower number of DE genes between H- and L-RFIfat steers. The association analyses of the gene expressions and FA profiles showed that 10 FA metabolism-associated genes together with the one upstream regulator (SREBF1) were associated with the proportion of C18:2n-6, total n-6, PUFA and PUFA/SFA for KC steers but not the other two breeds. Subcutaneous adipose tissue FA profiles and healthy FA index differed in cattle with divergent feed efficiency and such variation was unique for the three examined cattle breeds. Key FA metabolism-associated genes together with SREBF1 which is the upstream regulator of a set of genes involved in lipid metabolism may be of importance for genetic selection of meat with higher healthy FA index in beef cattle.