Nutritional composition for promoting conversion from ALA to DHA and application thereof

Abstract

The invention provides a nutritional composition for promoting conversion from ALA to DHA and application of the nutritional composition. The nutritional composition comprises goat milk and vegetable oil, the vegetable oil comprises at least one of sunflower seed oil, rapeseed oil and coconut oil; the mass ratio of the goat milk to the vegetable oil is (5-40): 1. The sheep milk fat can promote synthesis of DHA in the liver by increasing expression of a key enzyme in an ALA-DHA conversion pathway in the liver, so that the content of DHA in plasma is increased; and the DHA content in the cerebral cortex can be improved by increasing the expression of DHA important transporter MFSD2A in the cerebral cortex, so that the water maze learning and memory ability of the rats is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nutritional compositions, and in particular to a nutritional composition for promoting the conversion of ALA to DHA and application thereof. Background Art

[0002] Docosahexaenoic Acid (DHA) is a very important n-3 long-chain polyunsaturated fatty acid (LCPUFA) for the human body. It has physiological functions such as brain health, eyesight improvement, anti-cancer, anti-inflammatory, and prevention of cardiovascular diseases. DHA is particularly important for the brain development of infants and young children during their growth and development stage. In the early stages of life, infants' DHA intake is provided by breast milk, which contains 0.2-0.4% DHA, which meets the optimal nutritional level for infants in the first 6 months recommended by the World Health Organization. Infants can then supplement DHA through food intake, mainly through direct supplementation of DHA supplements such as fish oil, or by ingesting plant-derived α-linolenic acid (ALA) converted into DHA.

[0003] α-linolenic acid (ALA) is a precursor for synthesizing DHA. It is widely available, mainly in green leafy vegetables and plant seeds, and is easily obtained. Studies have found that ALA, a plant-based ω-3 fatty acid, can be converted into DHA, a long-chain polyunsaturated fatty acid, through a series of enzymatic reactions, but this conversion process is not particularly efficient, especially in the human body, where the efficiency of ALA conversion to DHA is usually less than 5%. Therefore, how to improve the efficiency of ALA conversion to DHA is a very important research topic in this field. Summary of the invention

[0004] In view of this, the present invention provides a nutritional composition for promoting the conversion of ALA to DHA and application thereof. The nutritional composition comprises goat milk, which can promote the conversion of ALA in vegetable oil to DHA.

[0005] In order to solve the technical problems raised in the background technology, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a nutritional composition, comprising:

[0007] goat milk and vegetable oil;

[0008] The vegetable oil includes at least one of sunflower oil, rapeseed oil and coconut oil;

[0009] The mass ratio of the goat milk to the vegetable oil is (5-40):1.

[0010] Furthermore, the vegetable oil includes sunflower oil, rapeseed oil and coconut oil; and the mass ratio of the sunflower oil, the rapeseed oil and the coconut oil is (35-60):(20-45):(10-25).

[0011] Furthermore, the content of α-linolenic acid in the nutritional composition is 1 wt. % to 4 wt. % of total fatty acids.

[0012] Furthermore, the goat milk comprises: at least one of raw goat milk, goat milk reconstituted with whole goat milk powder and pasteurized whole goat milk; and the fat content of the goat milk is 2wt.%-4wt.%.

[0013] Furthermore, the nutritional composition comprises: 83wt.% to 97wt.% goat milk, 1wt.% to 8.5wt.% sunflower oil, 0.8wt.% to 6wt.% low-erucic acid rapeseed oil, and 0.4wt.% to 5wt.% coconut oil.

[0014] In a second aspect, the present invention provides use of the nutritional composition as described above in the preparation of a product for promoting the conversion of α-linolenic acid into docosahexaenoic acid.

[0015] Furthermore, the performance of promoting the conversion of α-linolenic acid to docosahexaenoic acid includes at least one of the following:

[0016] Enhance learning and memory abilities;

[0017] Increased levels of fatty acid C22:5 and / or fatty acid C22:6 in plasma;

[0018] Increased content of fatty acid C22:6 and / or decreased content of fatty acid C20:5 in brain fatty acids;

[0019] The expression level of at least one of the desaturase FADS1, FADS2, carbon chain elongase ELOVL2, ELOVL5 and DHA transporter MFSD2A protein was increased.

[0020] In a third aspect, the present invention provides a food comprising the nutritional composition as described above and other acceptable auxiliary materials.

[0021] Furthermore, the food includes at least one of nutritional health products, infant formula milk powder, adult milk powder, food for special medical purposes, liquid milk, and complementary food.

[0022] In a fourth aspect, the present invention provides a medicine, comprising the nutritional composition as described above; and pharmaceutically acceptable excipients, wherein the excipients include excipients, diluents, fillers and / or absorption enhancers.

[0023] The beneficial effects of the above technical solution of the present invention are as follows:

[0024] The present invention provides a nutritional composition for promoting the conversion of ALA to DHA and its application, wherein the nutritional composition comprises: goat milk and vegetable oil; the vegetable oil comprises at least one of sunflower oil, rapeseed oil and coconut oil; the mass ratio of the goat milk to the vegetable oil is (5-40):1. The present invention finds that goat milk fat can promote the synthesis of DHA in the liver by increasing the expression of key enzymes in the ALA-DHA conversion pathway in the liver, thereby increasing the DHA content in plasma; and can increase the DHA content in the cerebral cortex by increasing the expression of MFSD2A, an important DHA transport protein in the cerebral cortex, thereby improving the water maze learning and memory ability of rats. The above research conclusions can provide theoretical support for the formula design of goat milk products and promote the refinement of the efficacy of goat milk products. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a protein gel electrophoresis diagram of enzymes related to the conversion of ALA to DHA in the liver. DETAILED DESCRIPTION

[0026] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than for limiting the present invention.

[0027] In a first aspect, the present invention provides a nutritional composition, comprising:

[0028] goat milk and vegetable oil;

[0029] The vegetable oil includes at least one of sunflower oil, rapeseed oil and coconut oil;

[0030] The mass ratio of the goat milk to the vegetable oil is (5-40):1.

[0031] According to some embodiments of the present invention, the vegetable oil includes sunflower oil, rapeseed oil and coconut oil; and the mass ratio of the sunflower oil, the rapeseed oil and the coconut oil is (35-60):(20-45):(10-25).

[0032] According to some embodiments of the present invention, the content of α-linolenic acid in the nutritional composition is 1 wt.% to 4 wt.% of total fatty acids.

[0033] According to some embodiments of the present invention, the goat milk comprises: at least one of raw goat milk, goat milk reconstituted with whole goat milk powder and pasteurized whole goat milk; and the fat content of the goat milk is 2wt.%-4wt.%.

[0034] According to some embodiments of the present invention, the nutritional composition includes: 83wt.% to 97wt.% goat milk, 1wt.% to 8.5wt.% sunflower oil, 0.8wt.% to 6wt.% low-erucic acid rapeseed oil, and 0.4wt.% to 5wt.% coconut oil.

[0035] ALA, a plant-based ω-3 fatty acid, can be converted into DHA, a long-chain polyunsaturated fatty acid, through a series of enzymatic reactions, but the efficiency of this conversion process is low. To address this problem, the present invention provides a nutritional composition, which includes: goat milk and mixed vegetable oils, wherein the mixed vegetable oils include at least one of sunflower oil, canola oil and coconut oil. The present invention found that compared with feeding the vegetable oil mixture alone, the DHA level in the brain of rats fed with a mixed diet of goat milk and vegetable oil was significantly increased. The results show that short-chain fatty acids in the milk fat in goat milk can promote the conversion of ALA to DHA, probably because the high oxidation of short-chain fatty acids in the body avoids the β-oxidation of ALA, thereby promoting the conversion of ALA to DHA. Furthermore, compared with cow's milk, the present invention also found that the effect of mixing goat milk and mixed vegetable oils is better. Specifically, the present invention found that goat milk fat can promote the synthesis of DHA in the liver by increasing the expression of key enzymes in the ALA-DHA conversion pathway in the liver, thereby increasing the DHA content in plasma; and can increase the DHA content in the cerebral cortex by increasing the expression of MFSD2A, an important DHA transport protein in the cerebral cortex, thereby improving the water maze learning and memory ability of rats. The above research conclusions can provide theoretical support for the formulation design of goat milk products and promote the refinement of the efficacy of goat milk products.

[0036] In a second aspect, the present invention provides a method for preparing the nutritional composition as described above, wherein the method comprises the following steps: pasteurizing, evaporating and concentrating the goat milk and homogenizing the goat milk, and then mixing the goat milk with the vegetable oil according to a mass ratio.

[0037] In a third aspect, the present invention provides use of the nutritional composition as described above in the preparation of a product for promoting the conversion of α-linolenic acid into docosahexaenoic acid.

[0038] According to some embodiments of the present invention, the performance of promoting the conversion of α-linolenic acid to docosahexaenoic acid includes at least one of the following:

[0039] Enhance learning and memory abilities;

[0040] Increased levels of fatty acid C22:5 and / or fatty acid C22:6 in plasma;

[0041] The content of fatty acid C22:6 in brain fatty acids is increased and / or the content of fatty acid C20:5 is decreased; and the expression level of at least one of the desaturase FADS1, FADS2, carbon chain elongation enzyme ELOVL2, ELOVL5 and DHA transporter MFSD2A protein is increased.

[0042] In a fourth aspect, the present invention provides a food, comprising the nutritional composition as described above, and other acceptable auxiliary materials.

[0043] According to some embodiments of the present invention, the food includes at least one of nutritional health products, infant formula milk powder, adult milk powder, food for special medical purposes, liquid milk, and complementary food.

[0044] In a fifth aspect, the present invention provides a medicine, which includes the nutritional composition as described above, and pharmaceutically acceptable excipients.

[0045] According to some embodiments of the present invention, the auxiliary materials include excipients, diluents, fillers and / or absorption enhancers.

[0046] According to some embodiments of the present invention, the drug is in the form of powder, tablet, granulation, microcapsule, liquid preparation and / or other dosage forms.

[0047] The present invention will be further described below through some specific embodiments.

[0048] The raw materials used in the following examples and comparative examples include:

[0049] Raw goat milk, source: goat milk provided by Ausnutria China.

[0050] Raw milk, source: milk provided by Ausnutria China.

[0051] Sunflower oil was purchased from: Bangilodes (Xiamen) Oil Technology Co., Ltd.

[0052] Low-erucic acid rapeseed oil was purchased from: Bangilodes (Xiamen) Oil Technology Co., Ltd.

[0053] Coconut oil was purchased from: Bangilodes (Xiamen) Oil Technology Co., Ltd.

[0054] Palm oil was purchased from: Bangi Lodes (Xiamen) Oil Technology Co., Ltd.

[0055] Example 1

[0056] Prepare nutritional composition 1:

[0057] Raw goat milk is pasteurized, heated, concentrated, and spray-dried to obtain whole goat milk powder, with a yield of 11.8%. The fat content of the whole goat milk powder is 30g / 100g, and the α-linolenic acid content is 117mg / 100g. The proportion of α-linolenic acid in fat is 0.39wt.%.

[0058] 49% of the total mass of the vegetable oil is sunflower seed oil, 33% of the low-erucic acid rapeseed oil and 18% of the coconut oil are mixed to prepare a mixed vegetable oil, wherein the content of α-linolenic acid in the mixed vegetable oil is 3.22 g / 100 g, and the proportion of α-linolenic acid in fat is 3.22%.

[0059] 45% of the total mass of the nutritional composition 1 is taken, and 20% of the mixed vegetable oil is added to 35% of the sodium carboxymethyl cellulose solvent to prepare the nutritional composition 1. In the nutritional composition 1, the ratio of the whole goat milk powder to the raw goat milk and the mixed vegetable oil is 45%÷11.8%:20%=19:1.

[0060] The fat content of the nutritional composition 1 is: 45% whole goat milk powder×fat content of whole goat milk powder (30%)+20% mixed vegetable oil×fat content of mixed vegetable oil (100%)=33.47%.

[0061] The content of α-linolenic acid in the nutritional composition 1: 45% whole goat milk powder×α-linolenic acid content of whole goat milk powder (0.12%)+20% mixed vegetable oil×α-linolenic acid content of mixed vegetable oil (3.22%)=0.69%.

[0062] The ratio of α-linolenic acid to total fat in the nutritional composition 1 is: the content of α-linolenic acid in the nutritional composition 1 ÷ the fat content of the nutritional composition 1 = 2.08%.

[0063] Example 2

[0064] Prepare nutritional composition 2:

[0065] Raw goat milk is pasteurized, heated, concentrated, and spray-dried to obtain whole goat milk powder, with a yield of 11.8%. The fat content of the whole goat milk powder is 30g / 100g, and the α-linolenic acid content is 117mg / 100g. The proportion of α-linolenic acid in fat is 0.39wt.%.

[0066] 49% of the total mass of the vegetable oil is sunflower seed oil, 33% of the low-erucic acid rapeseed oil and 18% of the coconut oil are mixed to prepare a mixed vegetable oil, wherein the content of α-linolenic acid in the mixed vegetable oil is 3.22 g / 100 g, and the proportion of α-linolenic acid in fat is 3.22%.

[0067] 17.6% of the total mass of the nutritional composition 2 and 29.9% of the mixed vegetable oil were added to 52.5% of the sodium carboxymethyl cellulose solvent to prepare the nutritional composition 2. In the nutritional composition 2, the ratio of the whole goat milk powder to the raw goat milk and the mixed vegetable oil was 17.6%÷11.8%:29.9%=5:1.

[0068] The fat content of the nutritional composition 2 is: 17.6% whole goat milk powder×fat content of whole goat milk powder (30%)+29.9% mixed vegetable oil×fat content of mixed vegetable oil (100%)=35.19%.

[0069] The content of α-linolenic acid in the nutritional composition 2: 17.6% whole goat milk powder×α-linolenic acid content of whole goat milk powder (0.12%)+29.9% mixed vegetable oil×α-linolenic acid content of mixed vegetable oil (3.2%)=0.98%.

[0070] The ratio of α-linolenic acid to total fat in the nutritional composition 2 is: the content of α-linolenic acid in the nutritional composition 2 / the fat content of the nutritional composition 2 = 2.79%

[0071] Example 3

[0072] Raw goat milk is pasteurized, heated, concentrated, and spray-dried to obtain whole goat milk powder, with a yield of 11.8%. The fat content of the whole goat milk powder is 30g / 100g, and the α-linolenic acid content is 117mg / 100g. The proportion of α-linolenic acid in fat is 0.39%.

[0073] 49% of the total mass of the vegetable oil is sunflower seed oil, 33% of the low-erucic acid rapeseed oil and 18% of the coconut oil are mixed to prepare a mixed vegetable oil, wherein the content of α-linolenic acid in the mixed vegetable oil is 3.22 g / 100 g, and the proportion of α-linolenic acid in fat is 3.22%.

[0074] 63.1% of the total mass of the nutritional composition 3 and 13.4% of the mixed vegetable oil were added to 23.5% of the sodium carboxymethyl cellulose solvent to prepare the nutritional composition 3. In the nutritional composition 3, the ratio of the whole goat milk powder to the raw goat milk and the mixed vegetable oil was 63.1%÷11.8%:20%=5:1.

[0075] The fat content of the nutritional composition 3: 63.1% whole goat milk powder×fat content of whole goat milk powder (30%)+13.4% mixed vegetable oil×fat content of mixed vegetable oil (100%)=32.32%.

[0076] The content of α-linolenic acid in the nutritional composition 3: 63.1% whole goat milk powder×α-linolenic acid content of whole goat milk powder (0.12%)+13.4% mixed vegetable oil×α-linolenic acid content of mixed vegetable oil (3.2%)=0.50%.

[0077] The ratio of α-linolenic acid to total fat in the nutritional composition 3 is: the content of α-linolenic acid in the nutritional composition 3 ÷ the fat content of the nutritional composition 2 = 1.56%.

[0078] Comparative Example 1

[0079] Prepare nutritional composition 4:

[0080] 49% of the total mass of the vegetable oil is sunflower seed oil, 33% of the low-erucic acid rapeseed oil and 18% of the coconut oil are mixed to prepare a mixed vegetable oil, wherein the content of α-linolenic acid in the mixed vegetable oil is 3.22 g / 100 g, and the proportion of α-linolenic acid in fat is 3.22%.

[0081] Nutritional composition 4 was prepared by taking 50% of mixed vegetable oil and 50% of sodium carboxymethyl cellulose solvent.

[0082] Comparative Example 2

[0083] Preparation of nutritional composition 5:

[0084] 49% of the total mass of the vegetable oil is sunflower seed oil, 33% of the low-erucic acid rapeseed oil and 18% of the coconut oil are mixed to prepare a mixed vegetable oil, wherein the content of α-linolenic acid in the mixed vegetable oil is 3.22 g / 100 g, and the proportion of α-linolenic acid in fat is 3.22%.

[0085] Nutritional composition 5 was prepared by taking 24.92% of mixed vegetable oil, 15.02% of pure palm oil (the ratio of α-linolenic acid to fat was 0.16%) and 60.1% of sodium carboxymethylcellulose solvent.

[0086] The fat content of the nutritional composition 5: 24.92% of the mixed vegetable oil×the fat content of the mixed vegetable oil (100%)+15.02% of the palm oil×the fat content of the palm oil (100%)=39.94%.

[0087] The content of α-linolenic acid in the nutritional composition 5: 24.92% of mixed vegetable oil×α-linolenic acid content of mixed vegetable oil (3.22%)+15.02% of palm oil×α-linolenic acid content of palm oil (0.16%)=0.83%.

[0088] The ratio of α-linolenic acid to total fat in the nutritional composition 5 is: the content of α-linolenic acid in the nutritional composition 5 ÷ the fat content of the nutritional composition 5 = 2.07%.

[0089] Comparative Example 3

[0090] Preparation of nutritional composition 6:

[0091] 49% of the total mass of the vegetable oil is sunflower seed oil, 33% of the low-erucic acid rapeseed oil and 18% of the coconut oil are mixed to prepare a mixed vegetable oil, wherein the content of α-linolenic acid in the mixed vegetable oil is 3.22 g / 100 g, and the proportion of α-linolenic acid in fat is 3.22%.

[0092] Nutritional composition 6 was prepared by taking 20.03% of mixed vegetable oil, 46.3% of whole milk powder (the ratio of α-linolenic acid to fat was 0.11%) and 33.7% of sodium carboxymethylcellulose solvent.

[0093] The fat content of the nutritional composition 6: 0.03% of the mixed vegetable oil×the fat content of the mixed vegetable oil (100%)+46.3% of the whole milk powder×the fat content of the whole milk powder (30%)=33.92%.

[0094] The α-linolenic acid content of the nutritional composition 6: 0.03% of mixed vegetable oil×α-linolenic acid content of mixed vegetable oil (3.22%)+46.3% of whole milk powder×α-linolenic acid content of whole milk powder (0.11%)=0.70%.

[0095] The ratio of α-linolenic acid to total fat in the nutritional composition 6 is: the content of α-linolenic acid in the nutritional composition 6 ÷ the fat content of the nutritional composition 6 = 2.05%.

[0096] test:

[0097] 1.1 Experimental animals and groups

[0098] SD rats, female, 4-5 weeks, 15 groups in each group, including a normal control group, Example 1-6 groups and Comparative Example 1-4 groups, fed with basic feed. During the experiment, they were allowed to eat and drink freely, and the light and dark cycle was 12h. Each intervention group was gavaged with fat from different sources for 45 consecutive days. The normal control group, Comparative Example 1 group, and Comparative Example 2 group were gavaged once in the morning and afternoon every day, and Example 1-3 groups and Comparative Example 3 groups were gavaged once in the morning and afternoon (each gavage was 5-7h apart). During the period, the weight of the animals was observed, and the height, diet and drinking water were measured. Gavage controlled the overall ALA intake of rats in each intervention group, and the overall intake of ALA was about 8μg / 100g body weight.

[0099] A water maze experiment was conducted one week before the end of the intervention, during which oral gavage was continued. After the intervention, blood and brain tissue were collected to detect DHA content; liver samples were collected to detect important catalytic enzymes in the ALA to DHA conversion pathway (FASD1, FASD2, ELOVL5, ELOVL2); and brain tissue was collected to detect DHA transporter indicators (MFSD2a).

[0100] After the animal behavior experiment, the rats were fasted but not watered for 12 hours, anesthetized with sodium pentobarbital, and blood samples were collected from the abdominal aorta after anesthesia to separate serum and plasma. The brain, hippocampus, liver, and kidney tissues of the rats were taken, washed with saline, and weighed, and the organ-to-body ratio (organ weight / body weight) of each organ was calculated, and then stored in a -80°C refrigerator. Some plasma and tissues were quickly frozen with liquid nitrogen and then stored in a -80°C refrigerator.

[0101] Serum and plasma were collected from a -80°C refrigerator, and total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen (BUN), and creatinine (CRE) in serum or plasma were detected according to the instructions of the biochemical kit. The kit was purchased from Nanjing Jiancheng Bioengineering Institute.

[0102] 1.2 Morris water maze test

[0103] Morris water maze test was performed 7 days before the end of intervention to evaluate the cognitive function of rats. Morris water maze is a circular pool with a diameter of 150 cm and a height of 60 cm and a black inner wall. The pool is evenly divided into 4 quadrants. The inner wall of each quadrant is marked with equal-sized square, star, triangle and circle markers to help rats enhance memory. The outer periphery is covered with a blackout curtain, and the water temperature is maintained at 23±2℃.

[0104] Day 0, adaptation period. One day before the navigation experiment, the platform was placed in the center of the target quadrant (quadrant 1), 1 cm above the water surface, and rats in each group were randomly placed in the water from a fixed quadrant and swam freely for 60 seconds to adapt to the water maze environment and become familiar with the platform position to reduce stress response.

[0105] On the 1st to 5th day, the positioning navigation experiment was carried out. After 5 consecutive days of training, the platform was placed in the center of the target quadrant (quadrant 1) and submerged about 1 cm in the water. The rats were given oral gavage intervention 30 minutes later and then put into the water. The rats were randomly placed in the pool from the second, third, and fourth quadrants facing the pool wall every day, and were allowed to swim in the water and find the platform by themselves. If the platform was found within 60 seconds, the escape latency time (i.e., the time from being put into the water surface to finding the platform) was recorded, and the rats were allowed to stay on the platform for 15 seconds; if the platform was not found within 60 seconds, the rats were guided to the platform and also allowed to stay on the platform for 15 seconds, with an escape latency of 60 seconds.

[0106] Space exploration experiment on day 6. The platform was removed, and the quadrant where the platform was originally placed was set as the target quadrant. The rats were placed in the water from the quadrant farthest from the platform (quadrant 3), and the number of times the rats crossed the platform within 90 seconds was measured, and the distance and time of the rats in the target quadrant (quadrant where the platform was located, i.e., quadrant 1) were recorded.

[0107] 1.3 GC-MS determination of fatty acids in plasma and brain tissue

[0108] Plasma fatty acid extraction and methylation: Take 50μl plasma, add 10μl heptadecanoic acid internal standard, extract lipids with 2ml methanol / n-hexane (4 / 1, v / v), mix well and slowly add 200ul acetyl chloride, cool to room temperature after 1h in a 60℃ water bath, add 4ml saturated Na2CO3 solution to terminate the reaction, add 0.5ml n-hexane, extract by ultrasonic for 10min, centrifuge at 2500rpm for 5min at room temperature, take the upper n-hexane, recover the upper phase (repeat twice), and use a refrigerated centrifugal concentrator for drying. The dried residue is stored at -80℃, and then re-dissolved with isooctane solution to determine the fatty acids.

[0109] Brain tissue fatty acid extraction and methyl esterification: Weigh 50 mg of brain tissue (prefrontal cortex), take an appropriate amount of methanol for homogenization, and the rest of the steps are the same as above.

[0110] GC-MS detection conditions: A Shimadzu gas chromatograph-mass spectrometer (GCMS-QP2010c) and a chromatographic column (Fame, 100m×0.25mm id×0.25μm, thermo) were used to detect fatty acids in plasma and brain tissue. The detection conditions were set as follows: the starting temperature of the column box was 80℃, maintained for 5min, and then heated to 280℃ at a rate of 4℃ / min and maintained for 20min; the injection temperature was 280℃, the split ratio was 10:1; the carrier gas was high-purity nitrogen, and the flow rate was 1mL per minute. The micro-injector was rinsed with solvent n-hexane and sample loading solution at least three times, and then the sample loading solution was repeatedly aspirated to empty the air in the injector. Finally, 1μL was drawn for injection to detect and separate fatty acid methyl esters. The Shimadzu LabSolutions chromatography workstation software was used to record the peak conditions. After the experiment was completed, the retention time, peak area and other results were exported for the next step of calculation and analysis.

[0111] 1.4 Western blot analysis of fatty acid conversion-related catalytic enzymes and DHA transport proteins

[0112] The liver of SD rats in each group was taken, cut into pieces, added with RIPA tissue lysis buffer (containing PMSF protease inhibitor, added before use), fully ground by high-throughput tissue grinder, centrifuged at 4°C, 12000rpm for 10min, aspirated the supernatant, and the protein concentration of the supernatant was determined by BCA protein assay kit. Each sample was added with 5×SDS protein loading buffer at a ratio of 1:4, heated at 100°C for 10min, denatured and loaded, and separated by 10% polyacrylamide gel electrophoresis, 80V constant voltage electrophoresis until bromophenol blue ran through the concentrated gel layer, and the separation gel electrophoresis voltage was 120V. Take out the gel, soak it in the transfer solution together with the PVDF membrane (immerse it in methanol for 30 seconds before use to activate it) and the filter paper, and mark it. Then assemble it into a "sandwich" sandwich device in the order of sponge pad-filter paper-gel-PVDF membrane-filter paper-sponge pad. After driving away the bubbles between the layers, place it in the transfer instrument, add an appropriate amount of transfer solution, constant voltage 80V, and transfer for 1.5 hours. After taking out the PVDF membrane, place it in 5% skim milk powder blocking solution on a shaker and block it at room temperature for 60 minutes; take out the blocked PVDF membrane and wash it with TBST 3 times, 5 minutes each time; then add the diluted primary antibody (FADS1, FADS2, ELOVL2, ELOVL5) and incubate it on a shaker at 4°C overnight; then wash it with TBST 3 times, 5 minutes each time; add the diluted secondary antibody (refer to the instruction manual for the dilution ratio) and incubate it on a shaker at room temperature for 1 hour; then wash it with TBST 3 times, 5 minutes each time. Finally, the samples were exposed for color development and photographed. ImageJ software was used for image analysis. The grayscale value of the target protein band was compared with the internal reference band, and the relative ratio was used to represent the relative expression level of the target protein.

[0113] 2. Experimental results

[0114] 2.1 General conditions of experimental animals

[0115] During the experiment, the SD female rats in each group ate and drank water freely, had shiny fur, were more active, and had normal urination and defecation.

[0116] 2.2 Weight

[0117] The body weight of rats in each group increased significantly with feeding time, and there was no significant difference in body weight gain between rats in each group before and after intervention.

[0118] 2.3 Body length, tail length and organ-to-body ratio

[0119] At the end of the experiment, there was no significant difference in body length and tail length among the rats in each group (P>0.05). Compared with the blank group, there was no significant difference in the coefficients of brain, hippocampus, liver and kidney in each intervention group (P>0.05).

[0120] 2.4 Blood lipids and liver and kidney function

[0121] After 45 days of intervention, the blood lipid metabolism indexes of rats in each group were measured. The results showed that compared with the blank group, there were no significant differences in total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in the intervention group (P>0.05); the serum (plasma) metabolic indexes of rats in each group were measured. The results showed that compared with the blank group, there were no significant differences in alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum urea nitrogen (BUN) and serum creatinine (CRE) in the intervention group (P>0.05).

[0122] 2.5 Water maze learning and memory ability

[0123] The learning latency of rats in each intervention group (n=10, x±s) is shown in Table 1.

[0124] The results showed that after 5 days of training, the latency of female rats in each group decreased. Compared with the blank group, the latency of female rats in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 on the 5th day to find the platform was significantly shortened (P < 0.05), and the learning ability of rats was enhanced. Compared with Comparative Example 1 and Comparative Example 2, the escape latency of Example 1 to find the platform was reduced on the 5th day, but no significant difference was found (P > 0.05).

[0125] In the learning and memory stage on the 6th day, compared with the blank group, the number of times Example 1 and Comparative Example 1 crossed the platform increased significantly (P < 0.05), and the number of times other intervention groups crossed the platform increased, but no significant difference was found (P > 0.05); compared with other intervention groups, the number of times Example 1 crossed the platform was significantly higher than other intervention groups (P < 0.05). This shows that compared with the vegetable oil mixture, the female rats in the sheep milk fat group with the same ALA content have stronger learning and memory abilities.

[0126] Table 1

[0127]

[0128]

[0129] 2.6 Plasma fatty acids

[0130] (1) Effects of each intervention group on plasma fatty acid content in rats

[0131] The test results of plasma fatty acids of SD female rats in each group are shown in Table 2. As can be seen from Table 2, compared with the blank group, the plasma DPA (C22: 5) and DHA (C22: 6) contents of Example 1 increased significantly (P < 0.05), indicating that the DHA content in the blood of female rats in the group of goat milk fat containing ALA was added to the diet increased, and the ALA conversion was improved. Compared with other intervention groups, the DHA content in the plasma of Example 1 was higher than that of Example 2, Example 3, Comparative Example 2, and Comparative Example 3 (P < 0.05), indicating that the addition of goat milk fat and vegetable oil mixed in the diet can increase the DHA content in the plasma of female rats, and there is no significant difference in the plasma DHA content with Comparative Example 1 in which 3.22% ALA was added to the diet (P > 0.05).

[0132] Table 2

[0133]

[0134]

[0135] 2.7 Brain fatty acids

[0136] The test results of brain fatty acids of SD female rats in each group are shown in Table 3. As can be seen from Table 3, compared with the blank group, the brain DHA (C22: 6) content of Example 1, Example 2, and Example 3 was significantly increased, and EPA (C20: 5) was significantly reduced (P < 0.05). Compared with other intervention groups, the DHA content in the brain of Example 1 was higher than that of Comparative Example 2 and Comparative Column 3 (P < 0.05), indicating that the addition of sheep milk fat and vegetable oil to the diet can increase the DHA content in the brain of female rats, and there is no significant difference with Comparative Column 1 in which 3.22% ALA is added to the diet. The brain DHA content in Example 1 is higher than that in Examples 2 and 3, but there is no significant difference.

[0137] Table 3

[0138]

[0139]

[0140] 2.8 Effects of each intervention group on enzymes involved in the conversion of ALA to DHA in the liver

[0141] Figure 1 The protein gel electrophoresis diagram of the enzymes involved in the conversion of ALA to DHA in the liver. Table 4 records the electrophoresis brightness of each group and the relative content of the standard substance β-actIn.

[0142] In each group of female rats, compared with the blank group, the protein expression levels of desaturase FADS1, FADS2, carbon chain elongation enzyme ELOVL2, and DHA transporter MFSD2A in Examples 1, 2, and 3 were increased (P < 0.05). Compared with the other intervention groups, the protein expression levels of FADS1 and FADS2 in rats in Example 1 were higher than those in Comparative Example 2 and Comparative Example 3 (P < 0.05).

[0143] Table 4

[0144]

[0145] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A nutritional composition, characterized in that The nutritional composition comprises: goat milk and vegetable oil; The vegetable oil includes at least one of sunflower oil, rapeseed oil and coconut oil; The mass ratio of the goat milk to the vegetable oil is (5-40):

1.

2. The nutritional composition according to claim 1, characterized in that The vegetable oils include sunflower oil, rapeseed oil and coconut oil; The mass ratio of the sunflower oil, the low-erucic acid rapeseed oil and the coconut oil is (35-60):(20-45):(10-25).

3. The nutritional composition according to claim 1, characterized in that The content of α-linolenic acid in the nutritional composition is 1 wt. % to 4 wt. % of total fatty acids.

4. The nutritional composition according to claim 1, characterized in that The goat milk comprises at least one of raw goat milk, goat milk reconstituted with whole goat milk powder and pasteurized whole goat milk; The fat content of the goat milk is 2wt.%-4wt.%.

5. The nutritional composition according to claim 2, characterized in that The nutritional composition comprises: 83 wt.% to 97 wt.% of goat milk, 1 wt.% to 8.5 wt.% of sunflower oil, 0.8 wt.% to 6 wt.% of low-erucic acid rapeseed oil, and 0.4 wt.% to 5 wt.% of coconut oil.

6. Use of the nutritional composition according to any one of claims 1 to 5 in the preparation of a product for promoting the conversion of α-linolenic acid into docosahexaenoic acid.

7. The use according to claim 6, characterized in that: The performance of promoting the conversion of α-linolenic acid to docosahexaenoic acid includes at least one of the following: Enhance learning and memory abilities; Increased levels of fatty acid C22:5 and / or fatty acid C22:6 in plasma; Increased content of fatty acid C22:6 and / or decreased content of fatty acid C20:5 in brain fatty acids; The expression level of at least one of the desaturase FADS1, FADS2, carbon chain elongase ELOVL2, ELOVL5 and DHA transporter MFSD2A protein was increased.

8. A food, characterized in that The food comprises the nutritional composition according to any one of claims 1 to 5; and other acceptable excipients.

9. The food according to claim 8, characterized in that The food includes at least one of nutritional health products, infant formula milk powder, adult milk powder, food for special medical purposes, liquid milk, and complementary food.

10. A medicine, characterized in that: The medicine comprises the nutritional composition according to any one of claims 1 to 5; and pharmaceutically acceptable excipients, including excipients, diluents, fillers and / or absorption enhancers.

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