Fatty acid profiles of muscle, liver, heart and kidney of Australian prime lambs fed different polyunsaturated fatty acids enriched pellets in a feedlot system

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

BACKGROUND

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

RESULTS

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

CONCLUSION

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

Differences in Chemical Composition, Polyphenol Compounds, Antioxidant Activity, and In Vitro Rumen Fermentation among Sorghum Stalks

The aim of the study was to examine the differences in the chemical composition, polyphenol compounds, antioxidant activity, and in vitro rumen fermentation among six varieties of sorghum stalks. The results show that maoliangnuo 1 (M1) contained a higher (p < 0.05) level of dry matter, and jinzhong 405 (J4) contained a higher (p < 0.05) level of crude protein content. The concentrations of neutral detergent fiber, acid detergent fiber, and cellulose were significantly higher (p < 0.05) in stalk jinliangnuo (JN). The levels of chlorogenic acid, homoorientin, isovitexin, vitexin, rhoifolin, genistin, quercetin, apigenin, aloe emodin, emodin, and total polyphenols were all significantly (p < 0.05) higher in maohongnuo 6 (M6) than in the other stalks. Moreover, stalk M6 contained higher (p < 0.05) levels of total antioxidant capacity (TAC), glutathione peroxidase (GPX), catalase (CAT), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging capacity. There were significant (p < 0.05) positive correlations between total polyphenols and TAC, superoxide dismutase, GPX, CAT, and DPPH free-radical scavenging capacity. The total gas production was significantly (p < 0.05) influenced by the sorghum stalk variety and incubation time. Stalk J4 displayed higher values for the (p < 0.05) immediately soluble fraction and the potential extent of gas production, while stalk M6 exhibited a significantly lower (p < 0.05) insoluble fraction level. Furthermore, stalk M6 exhibited a significantly higher level of (p < 0.05) ruminal fluid propionic acid, but its level of butyric acid and its ratio of acetic acid to propionic acid were both significantly lower (p < 0.05). Taken together, the results reported in this paper indicate that the chemical composition, polyphenol compounds, antioxidant activity, and in vitro rumen fermentation all vary greatly among different varieties of sorghum stalks.

Ewe early gestation supplementation with eicosapentaenoic and docosahexaenoic acids affects the liver, muscle, and adipose tissue fatty acid profile and liver mRNA expression in the offspring

Our objectives were to assess the effects of eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) supplementation to pregnant ewes during the first third of gestation on their offspring's liver, adipose, and muscle tissues fatty acid (FA) profile and liver mRNA expression after a finishing period receiving diets with different FA profiles. Twenty-four post-weaning lambs, blocked by sex and body weight, were used in a 2 × 2 factorial arrangement of treatments. The first factor was dam supplementation (DS) in the first third of gestation with 1.61% of Ca salts of palm fatty acid distillate (PFAD) or Ca salts enriched with EPA-DHA. Ewes were exposed to rams with marking paint harnesses during the breeding. Ewes started DS at the day of mating, considered day 1 of conception. Twenty-eight days after mating, ultrasonography was used to confirm pregnancy, and nonpregnant ewes were removed from the groups. After weaning, the offspring lambs were supplemented (LS, second main factor) with two different FA sources (1.48% of PFAD or 1.48% of EPA-DHA) during the growing and fattening phase. Lambs were fed the LS diet for 56 d and sent to slaughter, where the liver, muscle, and adipose tissue samples were collected for FA analysis. Liver samples were collected for relative mRNA expression for genes associated with FA transport and metabolism. The data were analyzed as a mixed model in SAS (9.4). In the liver, the amount of C20:5 and C22:6 (P < 0.01) increased in lambs with LS-EPA-DHA, while some C18:1 cis FA isomers were greater in the lambs from DS-PFAD. In muscle, amounts of C22:1, C20:5, and C22:5 increased (P < 0.05) in lambs born from DS-EPA-DHA. The adipose tissue amounts of C20:5, C22:5, and C22:6 were greater (P < 0.01) in lambs from LS-EPA-DHA. Interactions (DS × LS; P < 0.05) were observed for DNMT3β, FABP-1, FABP-5, SCD, and SREBP-1; having greater mRNA expression in liver tissue of LS-EPA-DHA, DS-PFAD and LS-PFAD, DS-EPA-DHA lambs compared with the lambs in the other two treatments. Liver ELOVL2 mRNA relative expression (P < 0.03) was greater in the offspring of DS-PFAD. Relative mRNA expression (P < 0.05) of GLUT1, IGF-1, LPL, and PPARγ increased in the liver from LS-EPA-DHA lambs. Dam supplementation during early gestation using with different FA sources changed the lipid FA profile in MT, LT, and SAT during the finishing period depending on the tissue and type of FA source administered during the growing phase.

Dietary linseed supplementation improves meat quality and flavor of sheep by altering muscle fiber characteristics and antioxidant capacity

Linseed as a common oil crop that has been implicated in regulating the meat quality of animals. The aim of this investigation was to establish the effects of dietary linseed supplementation on carcass traits, meat quality, muscle fiber characteristics, volatile compounds and antioxidant capacity of sheep. Twenty-four Sunit sheep were distributed into 2 groups with different diet: control (CO) fed a standard diet and linseed (LS, 8% of extruded linseed). The results showed that linseed not only increased M. longissimus thoracis (LT) increased the loin-eye area but also decreased pH24h, L* and shear force. Meanwhile, linseed increased mRNA expression of MyHCI and MyHCIIx and decreased in cross-sectional area (CSA) and muscle fiber diameter. In addition, linseed altered the composition of meat volatile flavor compounds, such as Z-10-Pentadecen-1-ol, pentanal, 2-Octenal, (E)-, decanal, butane, and 2-heptanone. Moreover, linseed increased total antioxidative capacity (T-AOC) activity, the mRNA expression of glutathione peroxidase (GSH-Px) and catalase (CAT), decreased malondialdehyde (MDA) content. Overall, the results suggest that linseed is an effective feed additive in improving meat quality and flavor. The underlying mechanisms for its effectiveness may be partly due to a change in muscle fiber characteristics and antioxidant capacity.

Fortification of diets with omega-3 long-chain polyunsaturated fatty acids enhances feedlot performance, intramuscular fat content, fat melting point, and carcass characteristics of Tattykeel Australian White MARGRA lambs

Meat eating quality indices such as intramuscular fat content (IMF) and fat melting point (FMP) of the Longissimus thoracis et lumborum muscle and the feedlot performance, carcass traits, and commercial wholesale cuts of lot-fed Tattykeel Australian White (TAW) MARGRA lambs as a result of dietary fortification of the diet with omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) were evaluated. A total of 75 TAW MARGRA lambs at 6 months of age with an average liveweight of 30 ± 1.2 kg were used. The lambs were randomly allocated to the following three dietary treatments of 25 lambs each in a 47-day feeding trial using a completely randomized experimental design: (1) control diet of hay plus pellets without omega-3 oil, (2) hay plus commercial whole grain pellets (MSM) without omega-3 oil, and (3) hay plus pellets fortified with omega-3 oil. It was hypothesized that dietary supplementation with omega-3 fortified pellets will improve feedlot performance, meat-eating quality indices of IMF, FMP, and carcass characteristics. Lot-fed lambs on the MSM whole grain had the highest feed intake of 1.69 kg/day, followed by the control at 1.57 kg/day and the lowest in the omega-3 diet at 1.01 kg/day (p = 0.0001). However, the omega-3 diet had the highest average daily gain of 230 g/head/day (p = 0.0001), indicating the greatest feed efficiency since it had the best growth response with minimal feed intake. Post-slaughter evaluation of the Longissimus thoracis et lumborum muscle revealed significant treatment variations in IMF (p = 0.0001), FMP (p = 0.0001), pH (p = 0.0380), and wholesale French rack primal cut (p = 0.0001). Strong correlations (p < 0.05) between liveweight, temperature, pH, FMP, and IMF were observed. Similarly, significant correlations between carcass characteristics of total saleable meat yield, lean trim, fat trims, bones, and leg shank were evident (p < 0.05). However, there were no treatment differences in the final liveweight, GR fat depth, hot standard carcass weight, or dressing percentage. The findings indicate that feedlot performance, meat-eating quality traits such as IMF and FMP, and commercial wholesale French rack cuts can be further improved during feedlot finishing of TAW MARGRA lambs through dietary supplementation with omega-3 oils, and hence the tested hypothesis of improved meat quality attributes is partially confirmed.

Dietary PUFAs drive diverse system-level changes in lipid metabolism

OBJECTIVE

Polyunsaturated fatty acid (PUFA) supplements have been trialled as a treatment for a number of conditions and produced a variety of results. This variety is ascribed to the supplements, that often comprise a mixture of fatty acids, and to different effects in different organs. In this study, we tested the hypothesis that the supplementation of individual PUFAs has system-level effects that are dependent on the molecular structure of the PUFA.

METHODS

We undertook a network analysis using Lipid Traffic Analysis to identify both local and system-level changes in lipid metabolism using publicly available lipidomics data from a mouse model of supplementation with FA(20:4n-6), FA(20:5n-3), and FA(22:6n-3); arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid, respectively. Lipid Traffic Analysis is a new computational/bioinformatics tool that uses the spatial distribution of lipids to pinpoint changes or differences in control of metabolism, thereby suggesting mechanistic reasons for differences in observed lipid metabolism.

RESULTS

There was strong evidence for changes to lipid metabolism driven by and dependent on the structure of the supplemented PUFA. Phosphatidylcholine and triglycerides showed a change in the variety more than the total number of variables, whereas phosphatidylethanolamine and phosphatidylinositol showed considerable change in both which variables and the number of them, in a highly PUFA-dependent manner. There was also evidence for changes to the endogenous biosynthesis of fatty acids and to both the elongation and desaturation of fatty acids.

CONCLUSIONS

These results show that the full biological impact of PUFA supplementation is far wider than any single-organ effect and implies that supplementation and dosing with PUFAs require a system-level assessment.

Lipid Metabolism, Carcass Characteristics and Longissimus dorsi Muscle Fatty Acid Composition of Tropical Crossbred Beef Cattle in Response to Desmanthus spp. Forage Backgrounding

Lipid metabolism, carcass characteristics and fatty acid (FA) composition of the Longissimus dorsi (loin eye) muscle were evaluated in tropical crossbred steers backgrounded on Desmanthus spp. (desmanthus) with or without feedlot finishing. It was hypothesized that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce carcasses with similar characteristics and FA composition. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were backgrounded for 140 days on Rhodes grass (Chloris gayana) hay augmented with 0, 15, 30 or 45 percent desmanthus on dry matter basis. Lucerne (Medicago sativa) hay was added to the 0, 15 and 30 percent desmanthus diets to ensure that they were isonitrogenous with the 45 percent desmanthus diet. After backgrounding, the two heaviest steers in each pen were slaughtered and the rest were finished in the feedlot for 95 days before slaughter. Muscle biopsy samples were taken at the beginning and end of the backgrounding phase. Carcasses were sampled at slaughter for intramuscular fat (IMF) content, fat melting point (FMP) and FA composition analyses. Increasing the proportion of desmanthus in the diet led to a linear increase in docosanoic acid (p = 0.04) and omega-6/omega-3 polyunsaturated FA ratio (n-6/n-3 PUFA; p = 0.01), while docosahexaenoic acid decreased linearly (p = 0.01). Feedlot finishing increased hot carcass weight, subcutaneous fat depth at the P8 site and dressing percentage (p ≤ 0.04). The n-6/n-3 PUFA ratio was within the recommended < 5 for human diets. IMF was within the consumer-preferred ≥3% level for palatability. The hypothesis that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce similar carcass characteristics and FA composition was accepted. These findings indicate that a combination of tropical beef cattle backgrounding on desmanthus augmented forage and short-term feedlot finishing produces healthy and highly palatable meat.

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

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

Nutritional Enhancement of Health Beneficial Omega-3 Long-Chain Polyunsaturated Fatty Acids in the Muscle, Liver, Kidney, and Heart of Tattykeel Australian White MARGRA Lambs Fed Pellets Fortified with Omega-3 Oil in a Feedlot System

Simple Summary

The problem addressed in this research was the possibility of enhancing the nutritional value and health beneficial omega-3 long-chain fatty acid content of lamb and its edible components. The aims and objectives were to evaluate the omega-3 contents of muscle, liver, kidney, and heart of lot-fed Tattykeel Australian White lambs of the MARGRA brand, in response to dietary supplementation with or without omega-3 oil fortified pellets. The findings demonstrate that the inclusion of omega-3 oil in feedlot diets of lambs enhances the human health beneficial omega-3 long-chain polyunsaturated fatty acid profiles of edible muscle tissue and organs without compromising meat quality or shelf life. These results are valuable to society because of increased functionality, health benefits, micro-marbling, tender, mouth-melting taste, and high-end eating quality experience of MARGRA lamb tissues and organs.

Abstract

The aim of this research was to evaluate the nutritional enhancement of omega-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) composition of edible lamb Longissimus thoracis et lumborum muscle, heart, kidney, and liver in response to dietary supplementation of lot-fed lambs with or without omega-3 oil fortified pellets. The hypothesis tested was that fortifying feedlot pellets with omega-3 oil will enhance the human health beneficial n-3 LC-PUFA composition of edible lamb muscle tissue and organs. Seventy-five Tattykeel Australian White lambs exclusive to the MARGRA brand, with an average body weight of 30 kg at six months of age, were randomly assigned to the following three dietary treatments of 25 lambs each, and lot-fed as a cohort for 47 days in a completely randomized experimental design: (1) Control grain pellets without oil plus hay; (2) Omega-3 oil fortified grain pellets plus hay; and (3) Commercial whole grain pellets plus hay. All lambs had ad libitum access to the basal hay diet and water. Post-slaughter fatty acid composition of the Longissimus thoracis et lumborum muscle, liver, kidney, and heart were determined using thee gas chromatography–mass spectrophotometry technique. Results indicated significant variations (p < 0.05) in fatty acid profiles between tissues and organs. Omega-3 oil fortified pellets significantly (p < 0.05) increased ≥C20 n-3 LC-PUFA (C20:5n-3 eicosapentaenoate, EPA + C22:5n3 docosapentaenoate, DPA + C22:6n3 docosahexanoate DHA); C18:3n-3 alpha-linolenate, ALA; C18:2 conjugated linoleic acid, CLA; total monounsaturated fatty acids, MUFA; polyunsaturated fatty acids, PUFA contents; and reduced the ratio of omega-6 to omega-3 fatty acids in all lamb organs and tissues without impacting shelf-life. The findings demonstrate that the inclusion of omega-3 oil in feedlot diets of lambs enhances the human health beneficial omega-3 long-chain polyunsaturated fatty acid profiles of edible muscle tissue and organs without compromising meat quality.

Plasma Metabolites, Productive Performance and Rumen Volatile Fatty Acid Profiles of Northern Australian Bos indicus Steers Supplemented with Desmanthus and Lucerne

The hypothesis tested was that tropical steers supplemented with the Desmanthus legume and lucerne, a widely characterized temperate legume of high nutritive value, would elicit similar responses in plasma metabolite profiles, productive performance, nitrogen retention, and volatile fatty acids (VFA). The tannin-binding compound, polyethylene glycol-4000 (PEG), was added to the diets (160 g/kg Desmanthus dry matter) with the objective of further exploring nitrogen (N) utilization in the animals supplemented with Desmanthus relative to lucerne. From February to June 2020, sixteen yearling Brangus steers (average liveweight of 232 ± 6 kg) were fed a background diet of Rhodes grass (Chloris gayana) hay for 28 days, before introducing three Desmanthus cultivars (Desmanthus virgatus cv. JCU2, D. bicornutus cv. JCU4, D. leptophyllus cv. JCU7) and lucerne (Medicago sativa) at 30% dry matter intake (DMI). Relative to the backgrounding period, all supplemented steers exhibited similar growth performance. Steers supplemented with Desmanthus recorded a lower DMI and animal growth performance, but higher fecal N concentration than animals supplemented with lucerne. Among the three Desmanthus cultivars, there were no significant differences in N concentrations, VFA, and plasma metabolite profiles. The addition of PEG induced higher rumen iso-acid concentrations and fecal N excretion. However, feeding Desmanthus spp. to tropical Bos indicus steers could be a valuable means of increasing N utilization, which is attributable to the presence of tannins, and, consequently, improve animal productive performance. Since supplementation with lucerne resulted in higher liveweight, daily liveweight gains, and overall animal performance than supplementing with Desmanthus, the tested hypothesis that both supplements will elicit similar animal performance does not hold and must be rejected. Further in vivo investigation is needed to better understand the impact of tannins in Desmanthus on N utilization.

Effect of supplementation with different fatty acid profile to the dam in early gestation and to the offspring on the finishing diet on offspring growth and hypothalamus mRNA expression in sheep

Supplementation with omega-3 and omega-9 fatty acids (FA) during late gestation regulates offspring development; however, their effect in the first third of gestation is unknown in sheep. The objective of this experiment was to evaluate the effects of the maternal supplementation with an enriched source of monounsaturated FA (MUFA) or an enriched source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) during the first third of gestation on productive performance on ewes and offspring, and hypothalamic neuropeptides on offspring. Seventy-nine post-weaning lambs, born of sheep supplemented in the first third of gestation with 1.61% Ca salts rich with MUFA or EPA+DHA (dam supplementation, DS), were distributed in a 2×2 factorial arrangement of treatments to finishing diets containing 1.48% of Ca salts of MUFA or EPA+DHA (lamb supplementation, LS). The finishing period of the offspring lasted for 56 d. During the finishing period dry matter intake (DMI, daily) and body weight (BW) were recorded. Plasma was collected for metabolites analysis. Twenty-four lambs were slaughtered, and hypothalamus was collected for mRNA expression of hormone receptors, neuropeptides, and lipid transport genes. The data were analyzed with a mixed model in SAS (9.4) using repeated measurements, when needed. There was a DS×LS interaction for BW (P = 0.10) where LS with EPA+DHA born from DS with MUFA were heavier than the other 3 treatments. Lambs born from DS with MUFA have a greater DMI (P < 0.01) than the offspring born from DS with EPA+DHA. Lambs born from MUFA supplemented dams had a greater (P ≤ 0.05) hypothalamus mRNA expression for cocaine and amphetamine regulated transcript, growth hormone receptor, metastasis suppressor 1, leptin receptor, pro-opiomelanocortin, and Neuropeptide Y. These results indicate that growth depends not on the type of FA during the finishing phase but the interaction of different sources of FA ad different stages. Also, supplementation with FA during early pregnancy changes productive performance and neuropeptides' mRNA expression of lambs independently of the finishing diet.

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

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

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

Meat eating quality with a healthy composition hinges on intramuscular fat (IMF), fat melting point (FMP), tenderness, juiciness, flavour and omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) content. These health-beneficial n-3 LC-PUFA play significant roles in optimal cardiovascular, retinal, maternal and childhood brain functions, and include alpha linolenic (ALA), eicosapentaenoic (EPA), docosahexaenoic (DHA) and docosapentaenoic (DPA) acids. The primary objective of this review was to access, retrieve, synthesise and critically appraise the published literature on the synthesis, metabolism and genetics of n-3 LC-PUFA and meat eating quality. Studies on IMF content, FMP and fatty acid composition were reviewed to identify knowledge gaps that can inform future research with Tattykeel Australian White (TAW) lambs. The TAW is a new sheep breed exclusive to MARGRA brand of lamb with an outstanding low fat melting point (28-39°C), high n-3 LC-PUFA EPA+DHA content (33-69mg/100g), marbling (3.4-8.2%), tenderness (20.0-38.5N) and overall consumer liking (7.9-8.5). However, correlations between n-3 LC-PUFA profile, stearoyl-CoA desaturase (SCD), fatty acid binding protein 4 (FABP4), fatty acid synthase (FASN), other lipogenic genes and meat quality traits present major knowledge gaps. The review also identified research opportunities in nutrition-genetics interactions aimed at a greater understanding of the genetics of n-3 LC-PUFA, feedlot finishing performance, carcass traits and eating quality in the TAW sheep. It was concluded that studies on IMF, FMP and n-3 LC-PUFA profiles in parental and progeny generations of TAW sheep will be foundational for the genetic selection of healthy lamb eating qualities and provide useful insights into their correlations with SCD, FASN and FABP4 genes.

Natural Oregano Essential Oil May Replace Antibiotics in Lamb Diets: Effects on Meat Quality

A study was conducted to investigate the effect of oregano essential oil (OEO) and monensin sodium on the oxidative stability, colour, texture, and the fatty acid profile of lamb meat (m. Longissimus lumborum). Twenty Dorper x Pelibuey lambs were randomly divided into five treatments; control (CON), monensin sodium (SM, Rumensin 200® 33 mg/kg), a low level of OEO (LO, 0.2 g/kg dry matter (DM)), a medium level of OEO (MO, 0.3g/ kg DM), and a high level of OEO (HO, 0.4 g/kg DM). Dietary supplementation of OEO at any concentration lowered the compression strength in comparison with CON and SM. MO had the highest a* values (7.99) and fatty acid concentration (C16:1n7, C18:1n9c, C18:1n6c, C20:1n9, and C18:2n6c) during storage for 7 d at 3 °C. Lipid oxidation was not promoted (p > 0.05) by the moderated supplementation of oregano essential oil; however, OEO at 0.3 g/kg DM showed a slight lipid pro-oxidant effect. Dietary supplementation of MO and SM had the same effect on colour, tenderness, and the fatty acid profile of lamb (L. lumborum). It was demonstrated that oregano essential oil was beneficial for lambs feeding, and it could be a natural alternative to replace monensin in lamb diets with improvements in the quality of the meat.

Improvement of Resveratrol Effects When Combined with Rice Oil in Rat Models of Inflammation

This study investigated the effects of systemic treatment with a new formulation of resveratrol (RSV) vehicled in rice oil (RSVO) in experimental rat models of inflammation. Male Wistar rats were evaluated in the following in vivo models: carrageenan-induced acute edema, complete Freund's adjuvant (CFA)-evoked sub-chronic edema, and CFA-induced polyarthritis. The animals were treated orally with RSVO (10-15 mg/kg) or RSV (100-200 mg/kg), depending on the experimental protocol. RSV was more effective than RSVO in carrageenan-elicited acute edema when dosed in either prophylactic or therapeutic schemes of administration. However, the repeated RSVO administration, at 10-fold lower doses, exhibited superior anti-inflammatory actions in either the sub-chronic edema or the chronic polyarthritis model elicited by CFA, when compared with RSV. The novel formulation RSVO displayed a lower plasma biotransformation when compared with the RSV-treated group-46% versus 88% of metabolites, respectively. RSVO also prevented polyarthritis-related cartilage destruction, an effect that might rely on the inhibition of the pro-inflammatory cytokine interleukin-6 (IL-6), associated with an increase of the anti-inflammatory cytokine interleukin-10 (IL-10). Noteworthy, the long-term administration of RSVO did not elicit any gastrointestinal harm. Our study revealed that RSVO was notably effective in the long-term inflammatory and degenerative responses triggered by CFA. This innovative formulation might well represent a promising alternative for treating chronic inflammatory diseases, such as arthritis.

Enhancing Omega-3 Long-Chain Polyunsaturated Fatty Acid Content of Dairy-Derived Foods for Human Consumption

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are termed essential fatty acids because they cannot be synthesized de novo by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. n-3 PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C20) n-3 PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of n-3 PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of n-3 PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of n-3 PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance n-3 PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of n-3 LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual n-3 LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of n-3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.