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

Abstract

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.

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

“…They were all 10-month-old lambs, with an average liveweight of 36.8 ± 0.3 kg (range of 36–38 kg for rams), 37.4 ± 0.4 kg (range of 37–38 kg for ewes), and an overall mean body condition score of 2.5 ± 0.01. Carcass performance and meat quality characteristics of TAW had been published [ 30 ]. An a priori power analysis was conducted using G-Power to justify an appropriate sample and effect size.…”

“…Research investigations of perceived sheepmeat eating quality sensory scores [ 28 ] and demographic influences [ 29 ] on Australian, American and Chinese consumers demonstrated a consistent consumer response to production factors of muscle type, sire, age, and sex. Evidence in the published literature [ 30 ] indicates that meat eating quality and fatty acid (FA) composition of lipids in tandem with variable fat deposition at the attainment of maturity, vary in the muscles of sheep due to differences in breed [ 31 , 32 , 33 , 34 ], physiological status, breeding systems [ 35 ], grass-fed versus concentrate feeding [ 36 , 37 ], and sex [ 38 , 39 ].…”

“…Linebreeding increases the frequency of desirable alleles, selection intensity and homozygosity, hence a tight culling regime and close monitoring of the inbreeding coefficient are key breeding management practices that ensure uniformity and consistency in TAW lamb eating quality. A comprehensive review of omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) metabolism and meat eating quality in TAW lambs [ 30 ] previously identified knowledge gaps in using Longissimus dorsi muscle biopsy sampling of ram and ewe lambs to directly determine the impact of linebreeding and gender on n-3 LC-PUFA, IMF and FMP contents while the animals are young and alive for early selection and breeding purposes. It also recommended the need for further research to better understand the genetic and nutritional interactions between dietary n-3 LC-PUFA oil supplements versus pasture grazing, finishing performance, carcass traits and the unique eating quality of TAW lambs to afford industry players the opportunity to consistently meet consumer preferences as well as key demand and supply determinants of profitability.…”

Dietary Coleus Amboinicus Herb Decreases Ruminal Methanogenesis and Biohydrogenation, and Improves Meat Quality and Fatty Acid Composition in Longissimus Thoracis of Lambs

“…The lack of alteration in the mRNA content of the ELOVL5 gene regulating FA elongation and the increased n-3 concentration (mainly LNA) in meat may re ect n-3 metabolism in the rumen, rather than that in muscles. Considering the reduced transcript content of another two genes-FADS1 and FASN-this may be linked to the inhibition of the initial stages of the BH process.Pewan et al [57]suggested that the FASN protein complex controls de novo biosynthesis of long-chain FA and affects FA deposition in meat, adipose tissue, and milk. The published evidence on the correlations between n-3 PUFA pro le, the activity of lipogenic genes (such as FASN), and meat quality, however, is very limited [57].Nevertheless, the n-3 PUFA pro le of the meat of lambs fed CAL was improved, which suggests that changes in the FA pro le had already occurred in the rumen, leading to more PUFA being available to the tissue.…”

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

“…Inter- and intra-breed differences are well known in terms of total IMF variability, with very obvious cases of genetic groups with higher marbling [ 127 , 128 ], while populations selected for other traits correlated to total fat, such as lean meat yield, have seen a decrease in IMF as a negative side effect [ 129 , 130 , 131 ] Studies show a medium to high heritability not only for total IMF, but also for the majority of fatty acid groups which can be endogenously synthesized in both ruminants and monogastrics [ 132 , 133 ]. According to GWAS studies in different species, both total IMF and fatty acid composition in meat are influenced by key regulatory genes with major effects and multiple genes with smaller effects, and have shown moderate to high heritability estimates for IMF and low to medium heritability for specific fatty acids [ 134 , 135 , 136 , 137 , 138 , 139 ]. However, despite the potential to include IMF fatty acids in breeding programs, antagonistic genetic relationships with performance have usually minimized the emphasis on selection for these traits.…”