Effects of Dietary Fat Sources on Occurrences of Conjugated Linoleic Acid and trans Fatty Acids in Rumen Contents

AbstractThe effects of three fat supplements on milk yield and composition were measured using 12 mid-lactation in-calf Hoistein-Friesian cows in a balanced incomplete change-over design over three periods each of 3 weeks. All cows received a basal diet consisting of 36 kg/day grass silage (dry matter (DM) 270 g/kg, metabolizable energy (ME) 11·6 MJ/kg DM) and 7 kg/day o f a concentrate mixture containing (g/kg) rolled barley (501), molassed sugar-beet pulp shreds (277), soya-bean meal (208) and a standard cow mineral supplement (14). Treatments were CON (control-no supplement); LIN and FISH (250 gl day of either linseed oil or marine oil, providing approximately 0·046 of ME intake) or TOA (95 glday of tuna orbital oil, providing 0·018 of total ME intake).There were no significant effects on silage DM intake or milk yield (means 9·25 and 17·2 kg/day respectively). The FISH and TOA treatments depressed (F < 0·05) milk fat concentration (45·4, 44·6, 34·5 and 41·6 (s.e.d. 1·08) g/kg for CON, LIN, FISH and TOA respectively; note — the same treatment order is used for all results quoted). Compared with values for CON, yield of f at (glday) was significantly (F < 0·05) greater for LIN and significantly lower for FISH (739, 808, 572 and 732, s.e.d. 28·7). All three oil supplements reduced (F < 0·05) milk protein content (33·6, 32·5, 30·6 and 32·4 (s.e.d. 0·43) g/kg) but, apart from a small increase for LIN, protein yield (glday) was unaffected (545, 586, 510 and 574, s.e.d. 20·2).The concentrations (g/100 g) of short-chain fatty acids (< C14) and C16 : 0 in milk f at were lower (F < 0·05) for LIN than for the other treatments. All supplements increased the concentrations ofC18:1 (F < 0·05), the value for LIN being greater (F < 0·05) than for the other treatments (21·0, 27·2, 25·3 and 23·7, s.e.d. 0·74). The FISH and TOA treatments increased (F < 0·05) the concentrations of long chain (< C2O) (n-3) poly-unsaturated fatty acids (PUFA), (0·19, 0·17, 0·49 and 0·27, s.e.d. 0·026) but less than proportionately 0·03 of dietary intake of these acids was transferred to milk, probably because they were found to be mostly in the phospholipid and cholesterol ester fractions of plasma. The FISH and TOA treatments increased (F < 0·05) the percentages of total trans fatty acids in milk fat (1·13, 2·19, 10·26 and 3·62, s.e.d. 0·728) whilst a significant (F < 0·05) increase in conjugated linoleic acid (CLA) was observed only for FISH (0·16, 0·28, 1·55, and 0·52, s.e.d. 0·154). Concentrations of CLA and total trans acids in milk were highly correlated (r = 0·91, no. =36, F < 0·001) whilst trans acids in milk were inversely correlated with milk fat content (r = -0·63, no. = 36, F < 0·001) supporting the theory that milk fat depression may be caused by increased supply of trans fatty acids to the mammary gland. The health implications of these changes in milk fat composition are discussed.

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Effect of conjugated linoleic acid and different type of dietary fat on serum lipid profile, liver enzymes activity and oxidative stress markers in wistar rats

Roczniki Państwowego Zakładu Higieny ◽

10.32394/rpzh.2019.0049 ◽

2018 ◽

pp. 27-33

Author(s):

Magdalena Franczyk-Żarów ◽

Edyta Kuś ◽

Renata B. Kostogrys

Keyword(s):

Fatty Acids ◽

Linoleic Acid ◽

Lipid Profile ◽

Conjugated Linoleic Acid ◽

Significant Influence ◽

Dietary Fat ◽

Serum Lipid ◽

Wistar Rats ◽

Liver Enzymes ◽

The Body

Background. Nutritional recommendations emphasize the need to limit consumption of saturated fatty acids and to increase the intake of polyunsaturated fatty acids in the prevention of non-communicable chronic diseases, particularly cardiovascular diseases. Among the fatty acids with health-related effects on the body, conjugated fatty acids are mentioned (i.e. CLA). Objective. The current study was designed to determine the effects of conjugated linoleic acid (CLA) on serum lipid profile, glucose, liver enzymes activity (AST and ALT), malonic dialdehyde (MDA) as well as lipid hydroperoxide (LPO) concentrations in rats fed diet differing in type of dietary fat. Material and methods. Male Wistar rats were divided into six groups and fed the following diets: control AIN-93G diet contained soybean oil (O) and diets with modification of fat source: butter (B) and margarine (M). The experimental diets were supplemented with 1% of conjugated linoleic acid (O+CLA, B+CLA, M+CLA). After 21 days the blood was collected and lipid profile, glucose, liver enzymes, MDA as well as LPO were analyzed. Results. The dietary treatments had no significant effect on the body weight and liver weight of the animals. The concentrations of total cholesterol (TC) and LDL+VLDL cholesterol were unchanged. Both experimental factors (fat source and CLA) had a significant influence on the TAG and HDL levels. Margarine (M) significantly increased the TAG concentration, whereas CLA had a significant impact on the TAG reduction (M+CLA). Glucose level was significantly decreased in all groups fed diets supplemented with CLA. Serum ALT significantly increased in all CLA groups. Fat source had statistically significant influence on the MDA concentration. The LPO level was significantly elevated in all CLA groups. There was statistically significant interaction of experimental factors (fat source and CLA supplementation) on LPO level. Conclusions. Margarine had an adverse effect on the rat’s lipid profile. However, in the group fed with margarine, the addition of CLA decreased the concentration of TAG. Regardless of the type of the dietary fat, CLA supplementation increased the level of LPO in the blood serum of animals.

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