Conjugated fatty acids and methane production by rumen microbes when incubated with linseed oil alone or mixed with fish oil and/or malate

Dietary whole and cracked linseed increases the proportion of oleic and α-linolenic acids in adipose tissues and decreases stearoyl-coenzyme A desaturase, acetyl-coenzyme A carboxylase, and fatty acid synthase gene expression in the longissimus thoracis muscle of Yanbian Yellow cattle

We hypothesized that supplementation of linseed in a beef cattle fattening diet would increase PUFA concentrations in intramuscular adipose tissue and depress (), (), and () gene expression by decreasing () expression. Conversely, supplemental linseed would upregulate expression of () and () in muscle of Yanbian Yellow steers. Thirty steers were assigned at random to 3 groups of 10 steers fed either the basal diet (corn grain and corn silage-based commercial concentrate [CON]), the CON diet plus 8% whole linseed (WLS; DM basis), or the CON diet plus 8% cracked linseed (CLS; DM basis) for 6 mo. The WLS and CLS supplements did not affect carcass weight, backfat thickness, or marbling scores ( > 0.10) but increased rib eye area and fat color (more yellow; < 0.05). The WLS and CLS diets decreased the proportions of 16:0 and 18:0 and increased the proportions of 18:1-9, 18:3-3, -9, -11 conjugated linoleic acid, total MUFA, and total PUFA in intramuscular, intermuscular, and subcutaneous adipose tissues. The WLS and CLS diets increased and gene expression whereas the supplements depressed , , , and gene expression in longissimus thoracis muscle, relative to CON muscle, consistent with our hypothesis. Because the WLS and CLS treatments did not affect any measure of carcass adiposity, these results indicated that linseed supplements promoted uptake of dietary lipids while concurrently depressing de novo fatty acid biosynthesis in adipose tissue.

Dietary linseed oil with or without malate increases conjugated linoleic acid and oleic acid in milk fat and and gene expression in mammary gland and milk somatic cells of lactating goats

Supplementary dietary plant oils have the potential to alter milk fatty acid composition in ruminants as a result of changes in the amount and kind of fatty acid precursors. We hypothesized that linseed oil in combination with malate (a key propionate precursor in the rumen) would increase ∆9 unsaturated fatty acids and specific gene expression in somatic cells and mammary glands of lactating goats. Twelve lactating goats were used in a 3 × 3 Latin square design. Treatments included the basal diet (CON), the CON plus 4% linseed oil (LO), and the CON plus 4% linseed oil and 2% -malate (LOM). Relative to CON, the LO and LOM supplements increased the daily intake of palmitic (16:0), stearic (18:0), oleic (18:1-9), linoleic (18:2-6), α-linolenic (18:3-3), and γ-linolenic acids (18:2-6); α-linolenic acid intake was increased over 9-fold, from 6.77 to over 51 g/d ( < 0.02). The LO and LOM supplements increased daily milk yield, milk fat yield, and milk fat percentage ( < 0.05). The LOM supplement also increased milk lactose percentage and daily yield ( = 0.03). Both the LO and LOM supplements increased plasma glucose and total cholesterol and decreased plasma β-hydroxbutyrate concentrations ( = 0.03). The LO and LOM supplements increased concentrations of stearic acid; -vaccenic acid (TVA; 18:1-11); -9, -11 CLA; -10 -12 CLA; and α-linolenic acid in rumen fluid and increased the concentrations of oleic acid; TVA; -9, -11 CLA; -10, -12 CLA; and α-linolenic acid in plasma lipids and milk fat ( < 0.05). Conversely, the LO and LOM supplements decreased short- and medium-chain SFA, including lauric (12:0), myristic (14:0), and palmitic acids, in plasma and milk fat ( < 0.05). Relative mRNA levels for and () gene expression were increased in somatic cells and mammary gland tissue by LO and LOM ( < 0.05). We conclude that the higher intake and ruminal production of stearic acid promoted SCD gene expression in somatic cells and mammary tissue. Furthermore, milk somatic cells are a suitable substitute for documenting treatment effects of dietary oils on gene expression in goat mammary tissue.