Nutrients. , 2020., Nov; 12(11): 3382.

Dietary Omega-3 Source Effect on the Fatty Acid Profile of Intramuscular and Perimuscular Fat—Preliminary Study on a Rat Model

Czyż K Sokoła-Wysoczańska, E Bodkowski, R et al.

Abstract

Fatty acids from the omega-3 family are an important element of both human and animal diets. Their activity involves a range of functions for the functioning of a whole organism, and their presence in animal diets can be considered as a means for animal origin product enrichment for human benefit or as compounds profitable for an animal’s health status. The aim of this preliminary study was to compare the effect of supplements rich in omega-3 fatty acids (linseed oil, linseed oil ethyl esters, and fish oil) in rat feed on the fatty acid profile of their intramuscular and perimuscular fat. The results demonstrated beneficial changes in fatty acid profiles (a decrease in saturated acids, an increase in unsaturated ones, i.e., omega-3 acids share) of examined tissues in the case of all supplements however, particular attention should be paid to linseed oil ethyl esters, which significantly increased the content of all omega-3 acids. Supplementation of animal diet with linseed oil ethyl esters may be beneficial for both animals, as omega-3 fatty acids exhibit profitable properties related to an animal’s health status and productivity, and humans who consume such enriched products.

Fatty acids from the omega-3 family are an important element of both human and animal diets. Their activity involves a range of functions for the functioning of a whole organism, and their presence in animal diets can be considered as a means for animal origin product enrichment for human benefit or as compounds profitable for an animal’s health status. The aim of this preliminary study was to compare the effect of supplements rich in omega-3 fatty acids (linseed oil, linseed oil ethyl esters, and fish oil) in rat feed on the fatty acid profile of their intramuscular and perimuscular fat. The results demonstrated beneficial changes in fatty acid profiles (a decrease in saturated acids, an increase in unsaturated ones, i.e., omega-3 acids share) of examined tissues in the case of all supplements however, particular attention should be paid to linseed oil ethyl esters, which significantly increased the content of all omega-3 acids. Supplementation of animal diet with linseed oil ethyl esters may be beneficial for both animals, as omega-3 fatty acids exhibit profitable properties related to an animal’s health status and productivity, and humans who consume such enriched products.

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Key Points

The aim of this preliminary study was to compare the effect of different supplements containing omega-3 fatty acids of a plant and animal origin applied in Wistar rat feed on the profile of fatty acids in their intramuscular and perimuscular adipose tissue, with special attention paid to the level of ALA, EPA, and DHA acids. The rationale for the study was an attempt to determine the profile of fatty acids in intramuscular and perimuscular fat on a rat model, with the possible use of tested supplements in the feeding of farm animals as a source of products that are an important part of the human diet.

The results of this study can be evaluated in two ways. The first relates to animal origin food enrichment with omega-3 fatty acids, which can lead to the production of so-called functional food and thus beneficial health-promoting effects in the consumers of such food. The second aspect is the effect of dietary supplementation of animals with omega-3 fatty acid sources on their health status and productivity, thus generating benefits for the animal organism and concurrent production from such supplementation.

There are various strategies aimed at improving meat lipid profiles and many of these include an increase in long-chain polyunsaturated fatty acid (LC-PUFA) content, especially those from the omega-3 family, i.e., alpha-linolenic acid (ALA, 18:3, n-3), eicosapentaenoic acid (EPA, 20:5, n-3), and docosahexaenoic acid (DHA, 22:6, n-3), and the supplements used in this study resulted in such profitable changes in the FA profiles of the analyzed samples.  This study found a higher conversion rate of ALA to EPA and DHA for linseed oil ethyl esters compared to the oil than that reported in the literature. The esters are produced in a nitrogen atmosphere without oxygen access therefore, we assume that the most important factor that may reduce the conversion of alpha-linolenic acid is related to the products of alpha-linolenic acid auto-oxidation. The preserved double bonds and lack of auto-oxidation products are the two main factors that guarantee a successful conversion of alpha-linolenic acid.

Linseed oil ethyl esters used in the study are characterized by a few- to several-fold higher bioavailability compared to the traditional triglyceride form, and are better absorbed and incorporated into various lipid fractions of blood, which is mainly caused by their simple molecular structure and more efficient kinetics of free acid release, ensuring more efficient digestion. Ethyl esters of linseed oil are characterized by very low toxicity, comparable to natural plant triglycerides, and an absence of very toxic substances from the cyanohydrate group (amygdalin, linamarin) present in the oil, which strongly damages liver cells, and complete resistance to the processes of acidic hydrolysis in liver environment which provides the possibility of transport to further parts of a gastrointestinal tract. They contain some health-promoting components of linseed oil such as phytoestrogens, and other phytosterols (campesterol, sitosterol), carotenoids, phospholipids, and other natural components. Oxygen solubility in esters is considerably lower compared to oil, which is reflected in a considerable increase in stability over longer time periods. They are also significantly less susceptible to the processes of oxidation, epoxidation, and peroxidation than is the case with the raw oil.

The study demonstrated that linseed oil ethyl esters may be a valuable source of omega-3 fatty acids, i.e., alpha-linolenic acid and its metabolites EPA and DHA, in animal diets supplementation aimed at animal origin products enrichment in pro-healthy fatty acids. Such supplementation of animals may be beneficial for both animals, as omega-3 fatty acids exhibit profitable properties related to animals health status and productivity, and humans who consume such enriched products.