Effect of weaning and sex on meat fatty acid profile of grazing lambs

Article Details: Received: 2020-10-20 | Accepted: 2020-11-27 | Available online: 2021-01-31https://doi.org/10.15414/afz.2021.24.mi-prap.25-28Twenty Tsigai and Suffolk crossbreed lambs in grazing conditions were used to investigate the effect of weaning status (weaned vs. unweaned) and sex on fatty acid composition of meat. Six males and four females were included in both groups, the weaned lambs group (WL) and the unweaned lambs group (UL). The fatty acid profile of Musculus longissimus lumborum et thoracis intramuscular fat (IMF) were determined by gas chromatography and analysed by analysis of variance. WL displayed higher proportion of t11-C18:1 (P < 0.001), n-6 polyunsaturated fatty acid (PUFA) C18:2 (P < 0.01) and C20:4 (P < 0.05), n-3 PUFA C18:3 (P < 0.05), C20:5 (P < 0.01), C22:5 (P < 0.05), C22:6 (P < 0.05) and the total PUFA (P < 0.01) in IMF than UL. On the contrary, IMF of UL had higher proportion of the medium-chain saturated fatty acids (SFA) such as C12:0 (P < 0.01), C14:0 (P < 0.01) and C16:0 (P < 0.01), the total SFA (P < 0.05) and the total monounsaturated fatty acids (MUFA) (P < 0.05). The weaning status had no significant effect on n-6/n-3 ratio, however the ratio was satisfactory low in both groups. The sex had no effect on a profile of essential and health beneficial fatty acids in meat of lamb. In conclusion, meat of weaned lambs in grazing system might be considered to obtain a higher proportion of healthy n-3 fatty acids compared to unweaned lambs.Keywords: fatty acids, intramuscular fat, lamb meat, weaned lambs, unweaned lambsReferencesBelanche, A. et al. (2019). Amulti-kingdom study reveals the plasticity of the rumen microbiota in response to a shift from non-grazing to grazing diets in sheep. Frontiers in Microbiology, 10, 1-17.Doi: https://doi.org/10.3389/fmicb.2019.00122Cañeque, V. et al. (2001). Effect of weaning age and slaughter weight on carcass and meat quality of Talaverana breed lambs raised at pasture. Animal Science, 73, 85-95.Cividini, A. et al. (2014). Fatty acid composition of lamb meat from the autochthonous Jezersko-Solčava breed reared in different production systems. Meat Science, 97(4), 480-485.Doi: https://doi.org/10.1016/j.meatsci.2013.12.012Cividini, A. et al. (2008). Fatty acid composition of lamb meat as affected by production system, weaning and sex. Acta Agriculturae Slovenica, Suplement 2, 47-52.De Brito, G. F. et al. (2017). TheEfect of Extensive Feeding Systems on Growth Rate, Carcass Traits, and Meat Quality of Finishing Lambs. Comprehensive Reviews. Food Science and Food Safety. 16(1), 23-38. Doi: https://doi.org/10.1111/1541-4337.12230Enser, M. et al. (1998). Fatty acid content and composition of UK beef and lamb muscle in relation to production systemand implications for human nutrition. Meat Science., 49, 329–341.French, P. et al. (2000). Fatty acid composition, including conjugated linoleic acid, of intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based diets. Journal of Animal Science, 78, 2849-2855.Howes, N. L. (2015). Opportunities and Implications of Pasture-Based Lamb Fattening to Enhance the Long-Chain Fatty Acid Composition in Meat. Comprehensive Reviews in Food Science and Food Safety, 14(1), 22-36. Doi: https://doi.org/10.1111/1541-4337.12118Jacques, J. et al. (2016). Meat quality, organoleptic characteristics, and fatty acid composition of Dorset lambs fed different forage to concentrate ratios or fresh grass. Canadian Journal of Animal Science, 97, 290-301.Doi: https://doi.org/10.1139/cjas-2016-0104Kosulwat, S. et al. (2003). Lipid composition of Australian retail lamb cuts with differing carcass classification characteristics. Meat Science, 65, 1413-1420.Margetin, M. et al. (2018). Fatty acids in intramuscular fat of Ile de France lambs in two different production Systems. Archives Animal Breeding, 61(4), 395-403. Doi: https://doi.org/10.5194/aab-61-395-2018Velasco, S et al. (2004). Effect of different feeds on meat quality and fatty acid composition of lambs fattened at pasture. Meat Science, 66(2), 457-465. Doi: https://doi.org/10.1016/S0309-1740(03)00134-7Velasco, S. et al. (2001) Fatty acid composition of adipose depots of suckling lambs raised under different production systems. Meat Science, 59(3), 325-333.Velasco, S. et al. (2000). Carcass and meat quality of Talaverana breed sucking lambs in relation to gender and slaughter weight. Animal Science, 70, 253-263.Woods, V. B., &Fearon, A. M. (2009). Dietary sources of unsaturated fatty acids for animals and their transfer into meat, milk and eggs: A review. Livestock Science, 126, 1-20

LAB/NTAL/ Lat2

LAB/NTAL/Lat2 is a transmembrane adaptor protein closely related to LAT. It is expressed in various myeloid and lymphoid cells, many of which also express LAT. Phosphorylation of LAB occurs following engagement of various ITAM- and non-ITAM-linked receptors and can play positive and negative roles following receptor engagement. LAT binds PLCγ directly, resulting in efficient Ca(2+) flux and degranulation. However, LAB does not contain a PLCγ-binding motif and only binds PLCγ indirectly, possibly via Grb2, thereby resulting in suboptimal signaling. As LAT can signal more efficiently than LAB, competition between the 2 for space/substrates in the lipid rafts can attenuate signaling. This competition model requires coexpression of LAT; however, LAB is repressive, even in cells lacking substantial LAT expression such as macrophages and mature B cells. The reported interaction between LAB and the ubiquitin E3-ligase c-Cbl suggests 1 possible mechanism for LAT-independent inhibition by LAB, but such a model requires further investigation. Given the wide-reaching expression pattern of LAB, LAB has the ability to modulate signaling in virtually every type of leukocyte. Regardless of its ultimate mode of action, the potent regulatory capability of LAB proves this protein to be a complex adaptor that warrants continued, substantial scrutiny by biochemists and immunologists alike