Effect of linseed supplementation of the gestation and lactation diets of dairy ewes on the growth performance and the intramuscular fatty acid composition of their lambs

In this study, we investigated the effects of maternal gestation and/or lactation diets supplemented with extruded linseed (rich in
18:3n-3) on growth performance and long-chain polyunsaturated faaty acid (PUFA) accumulation in muscle tissues of suckling
lambs. A total of 36 dairy ewes were fed a control diet (CON) and a diet containing linseed (LIN) during the last 8 weeks of
gestation and/or the first 4 weeks of lactation. The four dietary treatments consisted of the following gestation/lactation feeding
treatments: CON/CON, CON/LIN, LIN/LIN or LIN/CON. The lambs born from ewes fed the aforementioned diets were reared
exclusively on milk and were slaughtered at 4 weeks of age. Profiles of ewes’ milk fatty acids and that of intramuscular fat (IMF)
of leg muscles from lambs were determined. Compared with the CON/CON, LIN/CON offspring tended to grow slower and to have
reduced cold carcass weights. Moreover, the LIN supplementation only in the prepartum period (LIN/CON) resulted in greater
PUFAn-3 accumulation in the IMF compared with the CON/CON offspring due to increased 20:5n-3 (1.20 v. 0.64 mg/100 mg
of total FA), 22:5n-3 (1.91 v. 1.46;) and 22:6n-3 (1.25 v. 0.89) contents, respectively. Compared with the CON/CON diet,
providing LIN only during lactation (CON/LIN) caused a greater PUFAn-3 content in the IMF mainly due to a greater 18:3n-3
(1.79 v. 0.75 mg/100 g total FA) concentration. Continuous PUFAn-3 exposure, both via the maternal gestation and lactation diet,
had no additive effects on PUFAn-3 accumulation in tissues. The results suggest that linseed, as an 18:3n-3 source, seems to be
more efficient in increasing long-chain PUFAn-3 in fetal than in suckling lamb tissues.