Method for increasing eicosapentaenoic acid levels in animal plasma

Abstract

Disclosed herein is a method for increasing the plasma EPA:DHA ratio in a non-human animal by feeding the animal with a polyunsaturated fatty acid diet rich in DHA. An example of such a polyunsaturated fatty acid diet rich in DHA contains at least 0.6% DHA by weight of the feed. Also disclosed herein is an animal feed composition comprising polyunsaturated fatty acids rich in DHA. An example of such an animal feed composition is pet food.

Description

Technical Field

[0001] The present invention relates to a method for increasing EPA levels in the plasma of an animal to which DHA is orally administered at a fixed ratio of docosahexaenoic acid ("DHA") to eicosapentaenoic acid ("EPA").

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is an international application claiming priority to U.S. Provisional Application No. 62 / 970,932 filed on February 6, 2020, the entire contents of which are hereby incorporated by reference in their entirety. Background Art

[0004] The nutritional value of polyunsaturated fatty acids (PUFAs) such as ω-3 fatty acids is well known in the art. PUFAs are biologically important molecules that affect cell physiology due to their presence in cell membranes. PUFAs also regulate the production of gene expression of bioactive compounds and serve as biosynthetic substrates. For example, DHA accounts for about 15%-20% of lipids in the animal brain and 30%-60% of lipids in the retina (Jean-Pascal Bergé & Gilles Barnathan, Fatty Acids from Lipids of Marine Organisms: Molecular Biodiversity, Roles as Biomarkers, Biologically Active Compounds, and Economical Aspects, in Marine Biotechnology 1 49, T. Scheper, 2005). Evidence from multiple studies has shown that consuming the recommended amounts of EPA in the form of dietary supplements reduces inflammation (Lau CS, Morley KD, Belch JJ. Br. J. Rheumatol. 1993; 32(11):982-989; Kremer JM, Lawrence DA, Petrillo GF et al., Arthritis Rheum. 1995; 38(8):1107-1114). Because omega-3 fatty acids cannot be synthesized de novo by terrestrial animals, these fatty acids must be obtained from nutritional sources.

[0005] Polyunsaturated fatty acids are synthesized by microorganisms such as microalgae and fungi. Fish obtain polyunsaturated fatty acids by feeding on such microorganisms. Commercially, polyunsaturated fatty acids are obtained by extracting from fish, or by harvesting from microalgae or fungi via fermentation. Polyunsaturated fatty acids extracted from certain fish species, commonly referred to as "fish oils", have high EPA% and relatively low DHA%. Polyunsaturated fatty acids extracted from microalgae, commonly referred to as "algae oils", have various amounts of EPA and DHA. For example, some algae oils have high DHA% and relatively low EPA%. Some other algae oils have high DHA% and almost no EPA.

[0006] It is known that when animals need the health benefits associated with EPA, direct intake of large amounts of EPA can significantly increase the EPA concentration in the plasma of such animals. However, there are situations where direct intake of EPA is not feasible. For example, due to climatic reasons, the commercial supply of fish oil may sometimes be low. In other cases, the use of fish oil in premier pet food may be undesirable due to the presence of contaminants such as mercury.

[0007] Therefore, there is a need to increase the concentration of EPA in the plasma of an animal by supplying one or more types of polyunsaturated fatty acids other than EPA. Summary of the invention

[0008] The present invention relates to a method for increasing the plasma EPA:DHA ratio in a non-human animal, wherein the non-human animal is fed a feed comprising at least 0.6% by weight of DHA. In one embodiment, the feed comprises at least 0.68% by weight of DHA. In another embodiment, the feed also comprises 0.21% by weight or less of EPA. In another embodiment, the EPA:DHA ratio of the feed is 0.39:1 or less. In another embodiment, when compared to the plasma EPA:DHA ratio of a control group animal fed with a feed comprising 0.1% or less of DHA, the above-mentioned plasma EPA:DHA ratio is increased by at least one time. In another embodiment, when compared to the plasma EPA:DHA ratio of a control group animal fed with a feed not containing polyunsaturated fatty acids, the above-mentioned plasma EPA:DHA ratio is increased by at least 1 time, at least 2 times, at least 3 times, at least 4 times, or at least 5 times.

[0009] In some embodiments, the non-human animal is a pet animal, such as a dog, cat, or horse.

[0010] In some embodiments, the non-human animal is a monogastric animal, a ruminant, a zoo animal, a working animal, or livestock.

[0011] The present invention also relates to a method for obtaining a customized level of plasma EPA:DHA ratio in a non-human animal by feeding the non-human animal with a DHA-enriched feed, wherein the method comprises the following steps: 1) collecting three or more plasma EPA:DHA ratios in the non-human animal and their corresponding DHA levels in the feed; 2) calculating a correlation coefficient index based on the data in step 1); 3) determining a customized level of DHA in the feed using the correlation coefficient index in step 2); and 4) feeding the non-human animal with a feed containing the level of DHA determined in step 3).

[0012] In one embodiment, the non-human animal is a pet animal, such as a dog, cat, or horse.

[0013] In other embodiments, the non-human animal is a monogastric animal, a ruminant, a zoo animal, a working animal, or livestock.

[0014] The present invention also relates to a feed composition for a non-human animal for increasing the plasma EPA:DHA ratio in said non-human animal, wherein said feed comprises at least 0.6 wt. % DHA.

[0015] In one embodiment, the non-human animal is a pet animal, such as a dog, cat, or horse.

[0016] In other embodiments, the non-human animal is a monogastric animal, a ruminant, a zoological animal, a working animal, or a livestock animal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a graph showing the increase in the EPA:DHA ratio in cat plasma when cats were fed a diet containing different amounts of algal oil having a fixed EPA:DHA ratio.

[0018] Figure 2 is a graph showing the increase in the EPA:DHA ratio in dog plasma when dogs were fed a diet containing varying amounts of algal oil having a fixed EPA:DHA ratio. DETAILED DESCRIPTION

[0019] After reading the following detailed description, those skilled in the art can more easily understand the features and advantages of the present invention.It should be understood that, for clarity reasons, certain features of the present invention described in the context of separate embodiments may also be combined to form sub-combinations thereof.

[0020] The embodiments identified herein as exemplary are intended to be illustrative rather than restrictive.

[0021] It is an object of the present invention to provide a DHA-rich PUFA oil with a fixed EPA:DHA ratio, which PUFA oil can significantly increase the plasma EPA:DHA ratio in non-human animals.

[0022] The present invention achieves the above object by giving animals a threshold or higher level of DHA. The inventors have unexpectedly found that by providing animals with a DHA-rich oil with a fixed EPA:DHA ratio, the blood plasma EPA:DHA ratio of the animal increases with the increase of DHA levels in the DHA-rich oil taken in. Surprisingly, the EPA:DHA ratio in the animal's blood plasma is inconsistent with the EPA:DHA ratio in the DHA-rich oil taken in. On the contrary, after the animal takes in the DHA-rich oil, the EPA:DHA ratio in the animal's blood plasma becomes significantly higher than the EPA:DHA ratio of the oil fed to the animal. In other words, even when the EPA:DHA ratio of the oil taken in by the animal is fixed, the increase in the blood plasma EPA concentration in the animal is also significantly greater than the increase in the blood plasma DHA concentration. In addition, the inventors have found that when taking in a lower amount of DHA-rich oil, an excessive increase in EPA concentration in blood plasma will not occur. On the contrary, it only occurs after a minimum amount of DHA-rich oil has been taken in. Based on the above observations, the inventors have conceived a method for increasing the plasma EPA:DHA ratio in non-human animals by providing a DHA-enriched oil containing a threshold level of DHA. In one embodiment, the DHA-enriched oil has a fixed DHA% and EPA%, and therefore has a fixed EPA:DHA ratio.

[0023] Thus, the present invention discloses the minimum DHA levels required to significantly increase plasma EPA concentrations in non-human animals.

[0024] One embodiment of the invention relates to a method of increasing the plasma EPA:DHA ratio in a domestic animal, wherein the domestic animal is fed a feed comprising at least 0.6% by weight of DHA. In another embodiment, the feed may comprise at least 0.68% by weight of DHA. In other embodiments, the feed may comprise at least 0.7%, at least 0.8%, at least 0.9%, at least 1.0%, at least 1.1%, at least 1.2%, at least 1.3%, at least 1.4%, at least 1.5%, at least 1.6%, at least 1.7%, at least 1.8%, at least 1.9%, or at least 2.0% by weight of DHA.

[0025] As mentioned above, the inventors have found that by supplying a threshold level of DHA to non-human animals in feed, the EPA:DHA ratio in the animal's plasma can become significantly higher than the EPA:DHA ratio in the DHA-rich oil supplied in the diet. This observation indicates that the EPA in the diet may not be the only source that the animal absorbs into its plasma. The inventors assume that some of the DHA in the diet has been converted into EPA and has therefore led to an excessive increase in EPA in the plasma. However, this is just one of many possible hypotheses to explain the observations made by the inventors. The present invention should not be bound by this theory.

[0026] In the context of the present invention, the phrase "increases the plasma EPA:DHA ratio" means that the plasma EPA:DHA ratio is increased when a test group of animals given a DHA-enriched oil feed is compared to a control group of animals given the same feed except that it contains little or no such DHA-enriched oil. In one embodiment, the feed supplied to the control group animals contains less than 0.1% DHA. In another embodiment, the feed supplied to the control group animals does not contain DHA. In another embodiment, the feed supplied to the control group animals is completely free of PUFA oils. The plasma EPA:DHA ratio in the control group animals has an inherent plasma EPA:DHA ratio. In one embodiment, this inherent plasma EPA:DHA ratio in the control animals is 0.39:1 or about 0.39:1.

[0027] In another embodiment of the present invention, the feed provided to the test group animals not only comprises DHA, but also comprises other polyunsaturated fatty acids, such as EPA, arachidonic acid (arachidonic acid, ARA), docosapentaenoic acid (docosapentaenoic acid, DPA) n-3, DPAn-6, myristic acid, palmitic acid and palmitoleic acid. In one embodiment, the feed provided to the test group animals only comprises a small amount of EPA. In one embodiment, the amount of EPA in the feed provided to the test group animals is less than 0.21% by weight. In another embodiment, the feed provided to the test group animals does not contain EPA.

[0028] When a non-human animal is fed a feed containing at least 0.6% by weight of DHA, the methods disclosed in the present invention can significantly increase the plasma EPA:DHA ratio of the non-human animal. Such an increase was observed when the level of the plasma EPA:DHA ratio was compared to the level of the plasma EPA:DHA ratio of a control group animal. In one embodiment, the control group animal is fed a feed that does not contain PUFA oil. In another embodiment, the test group animal is fed a feed that does not contain DHA. In another embodiment, the control group animal is fed a feed containing less than 0.1% DHA. In another embodiment, the control group animal is fed a feed containing less than 0.1% DHA and EPA. In another embodiment, the control group animal is fed a feed containing less than 0.1% PUFA. In one embodiment, such an increase in the EPA:DHA ratio is doubled. In another embodiment, the increase in the EPA:DHA ratio is twofold. In another embodiment, the increase in the EPA:DHA ratio is threefold. In another embodiment, the increase in the EPA:DHA ratio is fourfold. In another embodiment, the increase in the EPA:DHA ratio is fivefold. The word "fold" or "one-fold" means an increase of 100% over the starting value. For example, if the mean plasma EPA:DHA ratio of the control group of animals is 0.4, a one-fold increase in the plasma EPA:DHA ratio is 0.8.

[0029] The present invention also makes it possible to increase the plasma EPA:DHA ratio of non-human animals to a target range or value. For example, if it has been found that a plasma EPA:DHA ratio of 2:1 has been shown to significantly reduce the occurrence of inflammation in cats, such EPA:DHA ratio can be achieved by supplying a feed containing an oil rich in DHA to a cat, wherein the oil rich in DHA has a DHA greater than 0.68% by weight of the feed. The inventors have found that by increasing the DHA level in the feed, the plasma EPA:DHA ratio of such animals can be significantly increased. As demonstrated in Example 1, the degree of increase in the EPA:DHA ratio can vary from animal to animal. However, the correlation coefficient index of any given animal can be determined by routine experiments. Therefore, the present invention relates to a method in which the plasma EPA:DHA ratio in a non-human animal is increased to a set level, wherein the non-human animal is fed with a feed containing a customized level of DHA with a fixed EPA:DHA ratio. The method comprises the following steps: 1) collecting three or more plasma EPA:DHA ratios in the non-human animal and their corresponding DHA levels in the feed; 2) calculating a correlation coefficient index based on the data in step 1); 3) using the correlation coefficient index in step 2) to determine the customized level of DHA in the feed; and 4) feeding the non-human animal with a feed containing the level of DHA determined in step 3). In one embodiment, when a feed with three or more different levels of DHA is fed to an animal, three or more plasma EPA:DHA ratios are measured in the animal. In some embodiments, at least three, at least four, at least five, at least seven plasma EPA:DHA ratios and their corresponding DHA levels in the feed are collected or measured in non-human animals. For example, in Example 1 of the present application, five plasma EPA:DHA ratios and their corresponding DHA levels in the feed were measured in cats and dogs.

[0030] The present invention relates to a feed composition comprising a PUFA oil rich in DHA, wherein the feed contributes to increasing the plasma EPA:DHA ratio in non-human animals. The source of such DHA-rich PUFA oil can be derived from a microorganism, such as a microalgae, a fungus, a bacteria, a yeast or a protist, or from a marine animal, such as a fish. Regardless of the source of the PUFA oil, it is preferred that such PUFA oil is rich in DHA. The term "rich in DHA" means that the %DHA in the PUFA oil is higher than the %EPA, %DPAn-3, %DPAn-6 and %ARA in the same oil. In some embodiments, the %DHA in the PUFA oil is higher than 20% by weight of the PUFA oil, higher than 30% by weight of the PUFA oil, higher than 40% by weight of the PUFA oil, and higher than 50% by weight of the PUFA oil.

[0031] The present invention relates to an animal feed composition for non-human animals, the animal feed composition comprising any of the PUFA oils of the present invention. In one embodiment, the animal feed composition is a pet food. In one embodiment, the animal feed composition is an animal feed.

[0032] "Animal" includes domestic animals; farm animals; zoo animals; competitive animals; breeding stock; racing animals; exhibition animals; heirloom animals; rare or endangered animals; companion animals; pet animals, such as dogs, cats, guinea pigs, rabbits, rats, mice or horses; primates, such as monkeys, apes, gorillas, baboons, gibbons and chimpanzees; canine mammals, such as dogs and wolves; feline animals, such as cats, lions and tigers; equine animals, such as horses, donkeys and zebras; food animals, such as cows, cattle, pigs and sheep; ungulates, such as deer and giraffes; or rodents, such as mice, rats, hamsters and guinea pigs; monogastric animals, such as cats, dogs, horses or pigs; or ruminants, such as cows and sheep, etc. Animal feed includes, but is not limited to, domestic animal feed including pet feed, zoo animal feed, working animal feed, livestock feed and combinations thereof. In a preferred embodiment, the method of the present application is applied to monogastric animals. However, the methods of the present application can also be applied to any non-monogastric animal, such as ruminants.

[0033] It is known that there are various feed receipts for any given animal species, and also various feeding regimes. Some of these feed receipts and feeding regimes differ significantly from others. However, the effect of the present invention is determined by the amount of polyunsaturated fatty acid oil used in the feed, especially the amount of DHA used, and is not affected by changes in feed composition or feeding regime.

[0034] Example

[0035] Example 1

[0036] Adult cats (>1 years old) and adult dogs (>1 years old) were given ordinary dry cat food or dog food for 4 to 5 weeks, and the dry cat food or dog food was supplemented with 0 weight %, 0.25 weight %, 1.44 weight %, 1.7 weight % or 5.1 weight % of the cat food or dog food. The algae oil used in the study contained 12.5% ​​EPA and 40% DHA, and the ratio of EPA to DHA was 0.31. The cats and dogs in the control group were fed with a control diet, in which poultry fat was used to replace 0.25%, 1.44%, 1.7% or 5.1% of the algae oil. According to the nutritional profile of the Association of American Feed Control Officials, AAFCO, dry pet food without algae oil supplementation (0%) is nutritionally comprehensive and balanced. This pet food without algae oil supplementation (0%) is a control diet. As a result, the EPA to DHA ratio of all test diets was 0.31.

[0037] All cats or dogs were fed with their control diet for at least 4 weeks before being given their designated test diet. The control group had 20 cats or dogs. The test groups each had 10 cats or dogs. Blood samples were collected at the end of the study. Plasma EPA and DHA concentrations were analyzed, and the EPA to DHA ratio in plasma was calculated.

[0038] Table 1 summarizes the plasma EPA to DHA ratio in cats and dogs. Dietary algal oil concentrations up to 1.44% did not affect the plasma EPA to DHA ratio (p>0.05), but the ratio increased numerically at higher dietary algal oil concentrations (1.44%). However, further increases in the amount of algal oil included in the feed (1.7% and 5.1%) significantly increased the plasma EPA to DHA ratio in both cats and dogs (p<0.05).

[0039] When the dietary algal oil concentration was 1.7%, the dietary EPA concentration was 0.21%, and the dietary DHA concentration was 0.68%.

[0040] Table 1

[0041]

[0042]

[0043] *: Student's t test, each test diet versus control diet

Claims

1. A method for increasing the plasma EPA:DHA ratio in a non-human animal for non-diagnostic or non-therapeutic purposes, wherein the non-human animal is fed a feed comprising at least 0.6% by weight DHA, wherein the EPA:DHA ratio of the feed is 0.39:1 or less.

2. The method according to claim 1, wherein the feed comprises at least 0.68% by weight DHA.

3. The method of claim 2, wherein the feed further comprises 0.21 wt% or less EPA.

4. The method of any one of claims 1-3, wherein the plasma EPA:DHA ratio is increased by at least double when compared to the plasma EPA:DHA ratio of a control group of animals fed a feed comprising 0.1% or less DHA.

5. The method of any one of claims 1-3, wherein the non-human animal is a pet animal.

6. The method of claim 5, wherein the pet animal is a dog, a cat or a horse.

7. The method of any one of claims 1-3, wherein the non-human animal is a monogastric animal.

8. The method of any one of claims 1-3, wherein the non-human animal is a ruminant.

Images