The purpose of this study was to evaluate the effect of rapeseed and linseed oil supplementations on performance and meat quality of lambs. The experiment was conducted on 18 growing (100-day-old) lambs of 19.7±1.9 kg live weight, assigned to 3 groups of 6 animals each. Control lambs were fed meadow hay and concentrate alone. Experimental animals additionally received rapeseed or linseed oils at a dose of 50 g/d. The lambs were slaughtered at an average body weight of 35.7±0.5 kg. The dressing percentage was higher in lambs fed rapeseed oil. Total saturated fatty acids (SFA) and C15:0, C16:0, C17:0, C21:0, C24:0 were lower in longissimus dorsi muscle (MLD) in lambs fed linseed oil. Supplementation of diet with linseed oil decreased concentrations of total monounsaturated fatty acids and C16:1, C17:1, C18:1 cis-9 in MLD. The concentrations of n-3 polyunsaturated fatty acids (PUFA) and C18:3 n-3, C20:5 n-3 in MLD were higher in lambs fed linseed oil than in other groups. Oils supplementation to diets resulted in increased concentration of C22:6 n-3 in MLD. The inclusion of linseed oil into the diet increased the contents of total PUFA, n-3 PUFA and C18:3 n-3, C20:5 n-3, C22:6 n-3 in semitendinosus muscle in comparison to control. A tendency towards a lower n:6/n:3 ratio in MLD was observed when lambs were supplemented linseed oil. The supplementation of linseed oil to diets seems to reduce the concentration of SFA and increase the concentration of n-3 PUFA. The n-6/n-3 ratio is an important nutritional factor, and its value has been favorably decreased below 2, thereby achieving an important target related to human health. Due to these changes carcass fatty acid profile was improved, and so enhanced lamb meat healthy properties.

Lambs were divided into 3 groups of 6 animals each. For 35 days lambs were fed a diet including 2% rapeseed oil, 1% fish oil and 0.1% carnosic acid (the control group) or two experimental diets supplemented with 0.35 mg ∙ kg⁻¹Se as selenized-yeast (SeY) (the SeY diet) or selenate (the selenate diet). Muscles (Musculus longissimus dorsi(MLD) andMusculus biceps femoris(MBF)), ruminal fluids and microbiota were collected from each lamb. SeY supplementation most effectively stimulated the accumulation of straight-chain volatile fatty acids (VFAs),iso-branched-chain VFAs, CO₂and CH₄in the ruminal fluid. The contents of CO₂, CH₄and VFAs including straight-chain VFAs with the exception ofiso-branched-chain VFAs were most effectively reduced by the selenite diet. The control diet most efficiently increased the concentration sums ofodd-saturated fatty acids (odd-SFAs) andiso-SFAs in microbiota. The SeY diet most efficiently reduced acetic acid to propionic acid ratio in the ruminal fluid. The selenate diet improved animal performance by reducing ruminal concentrations of CH₄and CO₂. The SeY diet and especially the selenate diet reduced the biohydrogenation to C18:0 when compared with the control diet. The selenate diet more efficiently reduced the concentration sums of all SFAs (ΣSFAs) and all fatty acids (ΣFAs) inMLDandMBFthan the SeY diet, which most effectively increased the concentrations of ΣSFAs and ΣFAs inMLDandMBF. The selenate diet most effectively increased the body mass gain of lambs.

During studies on fructan degradation in the rumen, a Treponema-like bacterium able to utilize Timothy grass fructan, commercial inulin and sucrose a