ABSTRACT
The effects of a monensin premix on milk fatty acid content during grain-induced subacute ruminal acidosis (SARA) in Holstein cows receiving a total mixed ration was investigated. Six multiparous, rumen-fistulated Holstein cows were used in a two-treatment, two-period crossover design with 6-wk periods. Experimental treatments were either a monensin premix or a placebo premix. At the beginning of wk 4, SARA was induced in experimental cows for a 10-d period using a grain challenge model. The administration of a monensin premix elevated milk fat proportion of total short-chain saturated fatty acids (sum of C4 to C15). Milk fat proportions of conjugated linoleic acid isomers were unaffected. Linolenic acid (C18:3n3) proportion in milk fat of monensin-treated cows were lower when compared with placebo-treated cows during the SARA period. Results from this study indicate that dietary supplementation with monensin during SARA had little effect on milk fatty acid content.
Subject(s)
Acidosis/veterinary , Cattle Diseases/prevention & control , Fatty Acids/analysis , Milk/chemistry , Monensin/adverse effects , Rumen , Acidosis/prevention & control , Analysis of Variance , Animals , Cattle , Cross-Over Studies , Female , Ionophores/adverse effects , Ionophores/therapeutic use , Linoleic Acid/analysis , Lipids/analysis , Monensin/therapeutic use , Placebos , alpha-Linolenic Acid/analysisABSTRACT
The lipids of Tropaeolum speciosum (T. speciosum) are a rich source of naturally occurring nervonic acid (24:1n-9). We report that adding a T. speciosum oil supplement to a semi-purified diet significantly increased the amount of 24:1n-9 in liver and heart, but not brain, sphingomyelin (SM) of young rats. The bioavailability of 24:1n-9 from the lipids of T. speciosum was similar to that of 24:1n-9 ethyl ester in this rat bioassay.
ABSTRACT
The occurrence of an unusual fatty acid, iso 24:0 (22-methyltricosanoic acid), has been shown to be present in the sphingomyelin from rat liver by gas liquid chromatography-mass spectrometry. The fatty acid is also present in the sphingomyelin of rat tissues tested, except for brain and fetal serum. Supplementation of diets with L-valine elevated the content of iso 24:0 in rat liver, heart, and kidney sphingomyelin. The fatty acid appears to be present in sphingomyelin of the sera of mice, dogs, and cats, but not humans.
Subject(s)
Fatty Acids/analysis , Liver/chemistry , Mammals/metabolism , Rats, Wistar/metabolism , Sphingomyelins/chemistry , Animals , Cats , Dogs , Male , Mass Spectrometry , Mice , Organ Specificity/physiology , Rats , Species SpecificityABSTRACT
Twenty-one groups of weanling male Wistar rats were fed semipurified diets containing 5% (w/w) of different dietary fats. After 2 wk, liver sphingomyelin (SM) fatty acid composition was determined. The ratio of 24:1 to 24:0 in liver SM varied over a tenfold range in response to dietary fat type. Step-wise multiple regression analysis indicated that dietary 24:1, 24:0, and 22:1 were the most significant factors in predicting the 24:1/24:0 ratio of liver SM. The mathematical relation between the dietary fatty acid composition and liver SM 24:1/24:0 was y = 1.88 (24:1) -1.49 (24:0) +0.21 (22:1) +0.01 (18:1) +0.26, r2 = 0.95, P < 0.0001. These results were confirmed by a second experiment in which the rats were fed olive oil-based diets supplemented with various fatty acid ethyl esters.
