The use of stoned olive cake and rolled linseed in the diet of intensively reared lambs: effect on the intramuscular fatty-acid composition

Abstract

The aim of the present study was to evaluate the effect of the inclusion of stoned olive cake and rolled linseed in a concentratebased diet for lambs on the fatty-acid composition of polar and non-polar intramuscular lipids of the longissimus dorsi muscle. To achieve this objective, 32 Appenninica lambs were randomly distributed into four groups of eight lambs each and were fed conventional cereal-based concentrates (diet C); concentrates containing 20% on a dry matter (DM) basis of rolled linseed (diet L); concentrates containing 35% DM of stoned olive cake (diet OC); and concentrates containing both rolled linseed (10% DM) and stoned olive cake (17% DM; diet OCL). The concentrates were administered together with grass hay at a 20 : 80 forage : concentrate ratio. Growing performances and carcass traits were evaluated. The fatty-acid composition was analysed in the total intramuscular lipids, as well as in the polar and neutral lipids. The average feed intake and the growth performance of lambs were not affected by the dietary treatments, as a consequence of similar nutritional characteristics of the diets. The inclusion of rolled linseed in the L and OCL diets increased the content of C18:3 n-3 in intramuscular total lipids, which was threefold higher in meat from the L lambs and more than twofold higher in meat from the OCL lambs compared with the C and OC treatments. The n-6 : n-3 ratio significantly decreased in the meat from lambs in the L and OCL groups, reaching values below 3. The L treatment resulted in the highest level of trans-18:1 fatty acids in the muscle. Regardless of the dietary treatment, the t10-18:1 was the major isomer, representing 55%, 45%, 49% and 45% of total trans-18:1 for C, L, OC and OCL treatments, respectively. Neutral lipids from the OC-fed lambs contained the highest amount of c9-18:1 (more than 36% of total fatty acids); however, the content of c9-18:1 did not differ between the OC and C lambs, suggesting an intensive biohydrogenation of dietary c9-18:1 in the case of OC treatment. The highest content of c9,t11-18:2 was detected in the intramuscular fat from the L-fed lambs, followed by the OCL treatment. A similar trend was observed in the neutral lipid fraction and, to a lower extent, in the polar lipids.

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

“…Some authors found an increase of LC-PUFAn-3 in lambs fed linseed diets (Noci et al, 2011;Berthelot et al, 2012), while others did not observe any effect (Bas et al, 2007). Others found that feeding ewes a n-3-enriched diet in lactation increased the proportion of 18:3n-3 and their longer chain derivatives in suckling lamb muscles (Gómez-Cortés et al, 2014;Mele et al, 2014), whereas Berthelot et al (2012) did not report such effects in their earlier experiment. Some studies in human and laboratory animals suggest that the conversion of ALA into LC-PUFA homologs increases during pregnancy probably due to the agonistic effects of the female sex hormones estrogen and progesterone (Kitson et al, 2010).…”

Volatiles in raw and cooked meat from lambs fed olive cake and linseed

“…The detailed animal management and diet composition was published by Luciano et al (2013) and by Mele et al (2014). Briefly, the feeding trial was conducted at the Experimental Station of the Department of Applied Biology at the University of Perugia, Italy and involved 32 Appenninica male lambs.…”

“…Recently, we have conducted a study to increase the concentration of PUFA n-3 fatty acids in lamb meat by feeding diets containing linseed (Mele et al, 2014). Considering that PUFA n-3 fatty acids are susceptible to oxidation, we have added olive cake into the diets and we found that the combination of linseed and olive cake effectively increased the content of n-3 PUFA in the muscle (Mele et al, 2014) and preserved the meat from rapid oxidation (Luciano et al, 2013).…”

“…Considering that PUFA n-3 fatty acids are susceptible to oxidation, we have added olive cake into the diets and we found that the combination of linseed and olive cake effectively increased the content of n-3 PUFA in the muscle (Mele et al, 2014) and preserved the meat from rapid oxidation (Luciano et al, 2013). Volatile organic compounds (VOCs) are produced through lipid oxidation, or through Maillard reaction or Strecker degradation (Mottram, 1998), which are responsible for meat flavour development.…”

“…We have hypothesized that the differences found previously in the meat fatty acid composition and oxidative stability could lead to differences in the meat volatiles. Therefore, using the solid-phase microextraction (SPME) and subsequent GC-MS analysis, we have determined the volatile compounds in the same meat samples used by Luciano et al (2013) and Mele et al (2014).…”