Concentrations of conjugated linoleic acid (cis-9, trans-11-octadecadienoic acid) are not increased in tissue lipids of cattle fed a high-concentrate diet supplemented with soybean oil1

Abstract

Conjugated linoleic acid (CLA), a mixture of isomers of linoleic acid, has many beneficial effects, including decreased tumor growth in animal cancer models. The cis-9, trans-11 isomer of CLA (CLA9,11) can be formed in the rumen as an intermediate in biohydrogenation of linoleic acid. Recent data, however, indicate that tissue desaturation of trans-fatty acids is an important source of CLA9,11 in milk. Our objective was to determine whether supplementing a high-corn diet with soybean oil (SBO; a source of linoleic acid) would increase concentrations of CLA in ruminal contents and tissue lipids. Four ruminally cannulated steers were utilized in a Latin square design with 28-d periods. A control diet (80% cracked corn, 2.0% corn steep liquor, 8.0% ground corn cobs, and 10% supplement [soybean meal, ground shelled corn, minerals, and vitamins]) was supplemented with 2.5, 5.0, or 7.5% (DM basis) SBO. Supplemental SBO did not affect ruminal pH or concentrations of the major VFA. The proportion and amount (mg FA/g DM ruminal contents) of CLA9,11 were not increased by increasing dietary SBO. However, the proportion and amount of the trans-10, cis-12 CLA isomer (CLA10,12) in ruminal contents increased linearly (P < 0.006) as dietary SBO increased. Trans-18:1 isomers in ruminal contents increased linearly (P < 0.02) as dietary SBO increased. The proportion of CLA10,12 was correlated positively (P < 0.001) with proportions of trans-C 18:1 isomers in ruminal contents. Conversely, CLA9,11 was correlated negatively (P < 0.05) with the proportions of trans-18:1 in ruminal contents. The same high-corn diet, supplemented with 0 or 5% SBO, was fed to 20 Angus-Wagyu heifers for 102 d in a randomized complete block design to determine the effect of added SBO on tissue deposition of CLA. Supplemental SBO did not affect feed intake, gain:feed, or carcass quality. Tissue samples were obtained from the hindquarter, loin, forequarter, liver, large and small intestine, and subcutaneous, mesenteric, and perirenal adipose depots. The concentration of CLA9,11 was greatest in subcutaneous adipose tissue but was not affected in any tissue by SBO. Supplementing high-corn diets with SBO does not increase CLA9,11 concentrations in tissues of fattening heifers. Research is needed to identify regulatory factors for pathways of biohydrogenation that lead to increased concentrations of CLA10,12 in ruminal contents when high-oil, high-concentrate diets are fed.

Animal performance and meat characteristics in steers reared in intensive conditions fed with different vegetable oils

“…These results contradict other studies that report higher levels of t 11-18:1 and c 9, t 11-18:2 after the addition of oils rich in linoleic and linolenic acids (Madron et al, 2002;McNiven et al, 2004;Erjaei et al, 2012). However, the results of this study are supported by other studies, such as those of Engle et al (2000) and Beaulieu et al (2002), who used 4% and 5% soybean oil supplements, respectively, and did not observe any increase in the c 9,t 11-18:2 content. Similarly, Raes et al (2004) found no significant differences in the t 11-18:1 or Means within rows with different superscript differ significantly (P < 0.05).…”

Production of trans C18:1 and conjugated linoleic acid in continuous culture fermenters fed diets containing fish oil and sunflower oil with decreasing levels of forage

“…In ewes, duodenal flow of t10c12 CLA increased and c9t11 CLA decreased in response to graded increments of dietary concentrate with a constant level (7.4 g/100 g diet DM) of supplemental FA from soya-bean oil (Kucuk and Hess, 2004). Our results support the findings of others (Beaulieu et al, 2002;Duckett et al, 2002;Shingfield et al, 2005) that high concentrate diets support t10c12 CLA formation in the rumen. Replacing incremental portions of red clover with maize grain in dual-flow continuous cultures resulted in a linear increase in the output of t10c12 CLA into effluent (Latham et al, 1972).…”

“…Trans10c12 CLA is a potent inhibitor of fat synthesis . What seems evident from this study and others (Beaulieu et al, 2002;Duckett et al, 2002;Kucuk and Hess, 2004) is that a high linoleic acid oil source along with low dietary F:C ratio has the greatest potential to increase t10c12 CLA. The t11t13 CLA was the second predominant isomer in the LF.…”

<b>Chemical and Fatty acid composition of different cuts cooked or uncooked from yearling bulls fed oil sources

“…According to Griswold et al (2003), there are two ways of CLA production, the first occurs with rumen biohydrogenation of linoleic acid and the second is the conversion of C18:1 t11 (trans vaccenic acid) into the CLA by means of the activity of Δ9-desaturase enzyme. Beaulieu et al (2002); Malau-Aduli et al (1997) commented that this enzyme is responsible for the desaturation of saturated fatty acids with 16 and 18-carbon, converting them into their corresponding monounsaturated forms, by adding a double bond at the carbon 9. The production of CLA by Δ9-desaturase is performed using the trans vaccenic acid (C18:1 t11), product of the incomplete biohydrogenation of linoleic and linolenic acids by the rumen bacteria.…”