Diet selection and n-3 polyunsaturated fatty acid deposition in lambs as affected by restricted time at pasture

Abstract

This study investigates the effects of restricted grazing time on forage selectivity and meat fatty acid deposition of lambs compared to a traditional grazing system. Results showed that the animals preferred to graze pasture species that were more palatable and lower in fibre, while demonstrating a partial preference for species with high protein levels. Leymus chinensis was more preferentially selected by lambs grazing pasture for shorter periods than longer periods. Lambs that grazed for 4 h per day had a high LNA (α-linolenic acid) intake. The accumulation of LNA and its elongation products in tissue was closely related to the LNA level in diet. Therefore, allowing lambs to graze for at least 4 h per day resulted in a meat fatty acid profile that is richer in health-promoting fatty acids. In particular, the highest DHA (docosahexaenoic acid) was observed in meat from lambs which grazed pasture for 4-h versus 8- and 12-h. It can be concluded that, in grassland systems, a healthier meat fatty acid profile for humans and the potential for better pasture management is achieved by limiting the grazing of lambs to 4 h per day rather than grazing over longer time periods.

Increased Levels of De-oiled Perilla Seed Meal in Broiler Diets to Enhance n-3 Fatty Acid Proportions and Improve Efficiency Levels

“…Consequently, n-3 and n-6 PUFA are generated by the Δ-5 and Δ-6 desaturase enzyme, stimulated by n-3 PUFA and a balance of the n-6:n-3 fatty acid ratio (Araya et al, 2004). Similar findings were revealed in the study of Zhang et al, 2017; who found higher C18:3 n-3 contents in broilers fed linseed oil. Moreover, our results presented higher C18:3 n-3 and PUFA levels in breast meat than in thigh meat lipids; as PUFA are preferentially incorporated into phospholipids (Hulan et al, 1988), which are in higher proportions in breast muscles than in thigh muscles (Ratnayake et al, 1989).…”

Effect of housing system and feed restriction on meat quality of medium-growing chickens

“…Pasture vegetation is also a source of healthy n3 polyunsaturated fatty acids ( Sun et al., 2012 ; Dal Bosco et al, 2016 ; Michalczuk et al., 2017 ; Zhang et al., 2017 ). Ponte et al.…”

Shorter Grazing Time and Supplementation Are Beneficial for Gastrointestinal Tract Development and Carcass Traits of Growing Lambs

“…Concurrently, restricted time at pasture with supplementation improves the growth performance of grazing sheep [ 5 ]. Our previous study found that restricting the grazing of lambs to 4 h per day improved grazing efficiency [ 6 ] and increased health-promoting n -3 unsaturated fatty acids in muscle tissue [ 7 ]. Restricted grazing with supplementation reduced the amount of movement and pasture intake of grazing sheep [ 6 , 7 ], which affected the development of the gastrointestinal tract as well as muscle fiber and carcass quality.…”

“…Our previous study found that restricting the grazing of lambs to 4 h per day improved grazing efficiency [ 6 ] and increased health-promoting n -3 unsaturated fatty acids in muscle tissue [ 7 ]. Restricted grazing with supplementation reduced the amount of movement and pasture intake of grazing sheep [ 6 , 7 ], which affected the development of the gastrointestinal tract as well as muscle fiber and carcass quality. The development of the gastrointestinal tract plays a vital role in nutrient digestion and absorption and muscle fibers impact meat quality [ 8 ].…”