Application of glucurolactone in preparation of feed for preventing and treating PRRSV infection, DON infection or PRRSV and DON combined infection

Abstract

The invention discloses application of glucurolactone in preparation of feed for preventing and treating PRRSV infection, DON infection or PRRSV and DON combined infection, and belongs to the technical field of animal feed. The glucurolactone is applied to preparation of feed for preventing and treating PRRSV infection, DON infection or PRRSV and DON combined infection. According to the invention, glucurolactone is used for preparing the feed, and glucurolactone in the feed can effectively improve the oxidation resistance of PRRSV infected, DON infected or PRRSV and DON combined infected pigs, improve the lung injury of the infected pigs, and improve the growth performance and health level of the infected pigs.

Description

Technical Field

[0001] The invention relates to the technical field of animal feed, and in particular to application of glucuronolactone in preparing feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection. Background Art

[0002] Deoxynivalenol (DON) is a trichothecene mycotoxin produced by Fusarium spp., which is commonly found in grains such as wheat and corn. In animal husbandry, long-term consumption of DON-contaminated feed by livestock will seriously damage growth performance and body health, reduce livestock feed intake, reduce efficiency, cause vomiting, diarrhea and even death, causing significant economic losses to farmers.

[0003] Porcine reproductive and respiratory syndrome virus (PRRSV) is a highly contagious RNA virus that can cause respiratory diseases in pigs (especially piglets). After PRRSV infection, PRRSV enters the cells of sick pigs and replicates inside the cells, which can cause cell necrosis, cell rupture and release a large number of subviral particles. These particles enter the lymphatic circulation and spread to immune organs such as lymph nodes and spleen, thereby causing damage to these immune tissues or organs.

[0004] Studies have shown that eating DON-contaminated feed can aggravate the symptoms of PRRSV infection in pigs, further reducing the growth performance and survival rate of pigs. Currently, antibiotics and other drugs have limited effects on the prevention and treatment of PRRSV infection, DON infection, or DON and PRRSV co-infection, and excessive use of antibiotics will lead to the gradual increase of bacterial resistance, so there are more and more restrictions on their use in animal feed. Summary of the invention

[0005] In view of this, the object of the present invention is to provide the use of glucuronolactone in the preparation of feed for preventing and treating PRRSV infection, DON infection, or combined infection of PRRSV and DON, so as to overcome the technical problem that the effect of preventing and treating PRRSV infection, DON infection, or combined infection of DON and PRRSV in the prior art is relatively limited.

[0006] In a first aspect, the present invention provides the use of glucuronolactone in preparing feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection.

[0007] Compared with the prior art, the present invention uses glucuronolide to prepare feed. The glucuronolide in the feed can effectively enhance the antioxidant capacity of pigs infected with PRRSV, DON, or PRRSV and DON, improve the lung damage of infected pigs, and promote the absorption and transport of nutrients, thereby improving the growth performance and health level of infected pigs.

[0008] Furthermore, based on the mass of the above feed, the effective amount of glucuronolactone added to the feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection is 50-600 mg / kg.

[0009] The above technical solution further limits the amount of glucuronolide added to the feed. Within the above addition amount range, glucuronolide can better play a preventive and therapeutic effect on PRRSV infection, DON infection, or PRRSV and DON combined infection, and further improve the growth performance and health level of infected pigs.

[0010] In a second aspect, the present invention provides a feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection, comprising a basal feed and glucuronolactone for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection.

[0011] Compared with the prior art, the feed of the present invention contains glucuronolactone, which can effectively alleviate the infection symptoms of pigs infected with PRRSV, DON, or PRRSV and DON, improve the lung damage of infected pigs, and reduce the serum and lung virus loads of infected pigs, thereby effectively improving the growth performance and health level of pigs.

[0012] Furthermore, the basic feed includes the following components: corn, protein substances, low-protein whey powder, oil, sugar, amino acid, feed additives, enzyme preparations and premixes.

[0013] The above technical solution further defines the composition of the basic feed, which can provide rich and balanced nutrients for pigs, especially piglets, and promote the growth and development of piglets.

[0014] Furthermore, based on the mass of the above-mentioned feed, the feed contains the following components: 450-650 parts of corn, 250-350 parts of protein substances, 40-80 parts of low-protein whey powder, 15-35 parts of oils and fats, 10-30 parts of carbohydrates, 3.2-7.6 parts of amino acids, 5.5-10 parts of feed additives, 1-3 parts of enzyme preparations, and 10-30 parts of premixes; based on the mass of the feed, the added amount of glucuron-lactone is 50-600 mg / kg.

[0015] The above technical solution further limits the content range of each component in the feed, within which the healthy growth of piglets can be further promoted.

[0016] Furthermore, the protein substances are soybean meal, puffed soybeans and fish meal; and / or the mass ratio of soybean meal, puffed soybeans and fish meal is (150-190):(80-115):(20-45).

[0017] The above technical solution further limits the types and proportions of protein substances. Soybean meal, puffed soybeans and fish meal can provide pigs with high-quality and easily digestible and absorbable protein, thereby promoting the growth and development of pigs.

[0018] Furthermore, the fat may be soybean oil or lard, etc.; and / or the sugar may be molasses, etc.

[0019] In the above technical solution, oil can significantly increase the energy level of feed and meet the energy requirements for rapid growth of pigs; sugars are easier to be digested and absorbed by pigs, which can improve the overall utilization rate of feed and reduce the burden of undigested substances on the intestines.

[0020] Furthermore, the amino acids are lysine, threonine and methionine; and / or the mass ratio of lysine, threonine and methionine is (2-4.2):(0.6-1.7):(0.6-1.7).

[0021] The above technical solution further limits the types and proportions of amino acids in feed, which can ensure that pigs obtain a balanced supply of amino acids to support their rapid growth, immune function, intestinal health and overall metabolism.

[0022] Furthermore, the feed additives are calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride; and / or the mass ratio of calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride is (0.8-1.5):(0.2-0.8):(2.0-3.5):(1.2-1.8):(1.3-2.4).

[0023] The above technical solution further limits the types and proportions of feed additives to ensure that pigs receive a comprehensive supply of minerals and electrolytes to support their bone health, immune function, intestinal health and overall metabolism.

[0024] Furthermore, the enzyme preparation is a mixture of lipase and amylase.

[0025] The above technical solution further limits the enzyme preparation to a mixture of lipase and amylase, which can simultaneously improve the digestibility of fat and starch and further optimize the nutritional value of the feed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the lung lesion condition of the infected piglets in Test Example 4.

[0027] Figure 2 The lung injury conditions and lung pathology scores of the infected piglets in Test Example 4.

[0028] Figure 3 This is the viral load in the serum and lungs of infected piglets in Test Example 4.

[0029] Figure 4 This is the lung inflammation condition of the infected piglets in Test Example 4.

[0030] Figure 5 The antioxidant levels in the plasma and lungs of the infected piglets in Test Example 4.

[0031] Figure 6 It is the gene expression level of antioxidant-related enzymes in the lungs of infected piglets in Test Example 4.

[0032] Figure 7 The expression levels of P-Nrf2 / Nrf2, HO-1, and Keap1 in the lungs of infected piglets in Test Example 4. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] In a first aspect, an embodiment of the present invention provides the use of glucuronolactone in preparing feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON co-infection.

[0035] The glucuronolactone added to the feed in the above technical solution can effectively improve the antioxidant levels in the plasma and lungs of pigs infected with PRRSV, DON, and especially those co-infected with PRRSV and DON, reduce lung inflammation, serum and lung viral loads of infected pigs, thereby reducing lung damage in infected pigs and improving the health and growth performance of infected pigs.

[0036] Further, on the basis of the above embodiment, the embodiment of the present invention further selects that the effective amount of glucuronolactone added to the feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection is 50-600 mg / kg, based on the mass of the feed. Preferably, the effective amount of glucuronolactone added to the feed for preventing and treating PRRSV infection can be 200-400 mg / kg, the effective amount of glucuronolactone added to the feed for preventing and treating DON infection can be 50-200 mg / kg, and the effective amount of glucuronolactone added to the feed for preventing and treating PRRSV and DON combined infection can be 200-600 mg / kg, more preferably 500-600 mg / kg. The above-mentioned amount of glucuronolactone has the best effect on the prevention and treatment of PRRSV infection, DON infection, or PRRSV and DON combined infection.

[0037] In a second aspect, the present invention provides a feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection, comprising a basal feed and glucuronolactone for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection.

[0038] Among them, the basic feed includes the following components: corn, protein substances, low-protein whey powder, oils, sugars, amino acids, feed additives, enzyme preparations and premixes.

[0039] Furthermore, the feed contains the following components, calculated by weight: 450-650 parts of corn, 250-350 parts of protein substances, 40-80 parts of low-protein whey powder, 15-35 parts of oils and fats, 10-30 parts of carbohydrates, 3.2-7.6 parts of amino acids, 5.5-10 parts of feed additives, 1-3 parts of enzyme preparations, and 10-30 parts of premixes; calculated by weight of the feed, the amount of glucuron-lactone added is 50-600 mg / kg.

[0040] For example, the corn in the feed can be 450 parts, 500 parts, 550 parts, 600 parts or 650 parts; the protein material can be 250 parts, 300 parts or 350 parts; the low protein whey powder can be 40 parts, 50 parts, 60 parts, 70 parts or 80 parts; the oil can be 15 parts, 20 parts, 25 parts, 30 parts or 35 parts; the sugar can be 10 parts, 22 parts or 30 parts; the amino acid can be 3.2 parts, 5.6 parts or 7.6 parts; the feed additive can be 5.5 parts, 8.5 parts or 10 parts; the enzyme preparation can be 1 part, 2 parts or 3 parts; the premix can be 10 parts, 20 parts or 30 parts; according to different infection conditions, the added amount of glucuron-lactone can be 50 mg / kg, 100 mg / kg, 200 mg / kg, 300 mg / kg, 400 mg / kg, 500 mg / kg or 600 mg / kg.

[0041] In some embodiments, the protein material can be selected from soybean meal, puffed soybean and fish meal. The mass ratio of soybean meal, puffed soybean and fish meal is (150-190): (80-115): (20-45), and for example, the mass ratio of soybean meal, puffed soybean and fish meal can be 150:80:20, 170:100:35 or 190:115:45.

[0042] In some embodiments, the oil can be selected as soybean oil or lard, and the sugar can be selected as molasses.

[0043] In some embodiments, the amino acids may be selected from lysine, threonine and methionine. The mass ratio of lysine, threonine and methionine is (2-4.2): (0.6-1.7): (0.6-1.7), and for example, the mass ratio of lysine, threonine and methionine may be 2: 0.6: 0.6, 3.2: 1.2: 1.2 or 4.2: 1.7: 1.7.

[0044] In some embodiments, the feed additive can be selected from calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride. The mass ratio of calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride is (0.8-1.5): (0.2-0.8): (2.0-3.5): (1.2-1.8): (1.3-2.4), and for example, the mass ratio of calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride can be 0.8: 0.2: 2.0: 1.2: 1.3, 1.3: 0.6: 3: 1.6: 2 or 1.5: 0.8: 3.5: 1.8: 2.4.

[0045] In some embodiments, the enzyme preparation can be selected as a mixture of lipase and amylase, wherein the mass ratio of lipase to amylase is 1:1.

[0046] In some embodiments, the premix provides the following components per kilogram of feed, based on the mass of each kilogram of feed: 9000 IU of vitamin A, 900 IU of vitamin D, 150 mg of vitamin E, 1.15 mg of thiamine, 3.48 mg of riboflavin, 31.4 mg of niacin, 5.3 mg of pyridoxine, 18 g of vitamin B12, 0.06 mg of biotin, 10.4 mg of pantothenic acid, 0.31 mg of folic acid, 95 mg of zinc, 105 mg of iron, 5.8 mg of copper, 3.69 mg of manganese, 0.15 mg of iodine, and 0.29 mg of selenium.

[0047] It should be understood that the raw materials used in the following examples are all commercially available raw materials unless otherwise specified.

[0048] Example 1

[0049] The invention provides a feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection. The feed comprises the following components: 547.9 g corn, 170 g soybean meal, 100 g puffed soybean, 35 g fish meal, 80 g low-protein whey powder, 20 g soybean oil, 22 g molasses, 3.2 g lysine, 1.2 g threonine, 1.2 g methionine, 1.3 g calcium hydrogen phosphate, 0.6 g stone powder, 3 g salt, 1.6 g zinc oxide, 2 g choline chloride, 1 g lipase and amylase mixture, 10 g premix, and 200 mg glucuronolactone.

[0050] Example 2

[0051] The invention provides a feed for preventing and treating PRRSV infection or PRRSV and DON combined infection. The feed comprises the following components: 573.3 g corn, 150 g soybean meal, 80 g puffed soybean, 20 g fish meal, 70 g low-protein whey powder, 35 g soybean oil, 30 g molasses, 2 g lysine, 0.6 g threonine, 0.6 g methionine, 0.8 g calcium hydrogen phosphate, 0.2 g stone powder, 2.0 g salt, 1.2 g zinc oxide, 1.3 g choline chloride, 3 g lipase and amylase mixture, 30 g premix and 400 mg glucuronolactone.

[0052] Example 3

[0053] The invention provides a feed for preventing and treating DON infection. The feed comprises the following components: 545.4.9g corn, 190g soybean meal, 115g puffed soybean, 45g fish meal, 40g low-protein whey powder, 15g lard, 10g molasses, 4.2g lysine, 1.7g threonine, 1.7g methionine, 1.5g calcium hydrogen phosphate, 0.8g stone powder, 3.5g salt, 1.8g zinc oxide, 2.4g choline chloride, 2g lipase and amylase mixture, 20g premix and 50mg glucuronolactone.

[0054] Example 4

[0055] The invention provides a feed for preventing and treating PRRSV and DON combined infection. The feed comprises the following components: 572.9 g corn, 170 g soybean meal, 100 g puffed soybean, 35 g fish meal, 50 g low-protein whey powder, 25 g soybean oil, 22 g molasses, 3.2 g lysine, 1.2 g threonine, 1.2 g methionine, 1.3 g calcium hydrogen phosphate, 0.6 g stone powder, 3 g salt, 1.6 g zinc oxide, 2 g choline chloride, 1 g lipase and amylase mixture, 10 g premix and 500 mg glucuronolactone.

[0056] Example 5

[0057] The invention provides a feed for preventing and treating PRRSV and DON combined infection. The feed comprises the following components: 577.9 g corn, 170 g soybean meal, 100 g puffed soybean, 35 g fish meal, 60 g low-protein whey powder, 30 g lard, 22 g molasses, 3.2 g lysine, 1.2 g threonine, 1.2 g methionine, 1.3 g calcium hydrogen phosphate, 0.6 g stone powder, 3 g salt, 1.6 g zinc oxide, 2 g choline chloride, 1 g lipase and amylase mixture, 10 g premix and 600 mg glucuronolactone.

[0058] Comparative Example 1

[0059] The difference between the feed for preventing and treating PRRSV infection or PRRSV and DON co-infection provided in Example 2 is that an equal amount of glucuronolactone is replaced by ribavirin.

[0060] Comparative Example 2

[0061] The difference between the feed for preventing and treating PRRSV and DON co-infection provided in Example 4 is that an equal amount of glucuronolactone is replaced by ribavirin.

[0062] Comparative Example 3

[0063] The only difference from the feed for preventing and treating DON infection provided in Example 3 is that an equal amount of glucuronolactone is replaced by amoxicillin.

[0064] Comparative Example 4

[0065] The only difference from the feed for preventing and treating DON infection provided in Example 3 is that the amount of glucuronolactone added to the feed is set to 1 g.

[0066] Comparative Example 5

[0067] The difference from the feed for preventing and treating PRRSV infection or PRRSV and DON co-infection provided in Example 2 is that the amount of glucuronolactone added to the feed is set to 1 g.

[0068] Comparative Example 6

[0069] The only difference from the feed for preventing and treating PRRSV and DON co-infection provided in Example 4 is that the amount of glucuronolactone added to the feed is set to 1 g.

[0070] Test Example 1

[0071] The effect of feed on the growth performance of PRRSV-infected piglets was tested using the following methods:

[0072] 40 21-day-old weaned piglets with an average body weight of 7.41±0.15 kg were selected and divided into 4 groups. They were fed with the feeds in Examples 1 and 2 and Comparative Examples 1 and 5, 4 times a day, and were allowed to eat freely. On the 15th day of feeding, all piglets were injected with 2.0 ml of PRRSV (10 5 TCID 50 / ml) to infect piglets with PRRSV, and then continue to raise them for 3 weeks, and then test the growth performance of PRRSV-infected piglets. The test results are shown in Table 1.

[0073] Table 1

[0074] Average daily weight gain (g / d) Average daily feed intake (g / d) Material weight ratio Example 1 485 665 1.37 Example 2 449 617 1.46 Comparative Example 1 360 584 1.56 Comparative Example 5 334 497 1.49

[0075] From the results in Table 1, it can be seen that after the equal amount of glucuronolactone was replaced by ribavirin in Comparative Example 1, the average daily weight gain and average daily feed intake of piglets decreased, and the feed-to-weight ratio increased, indicating that the glucuronolactone in the feed of the present invention can improve the growth performance of piglets infected with PRRSV.

[0076] In Comparative Example 5, after the addition amount of glucuronolactone in the feed was set to 1 g, the average daily weight gain and average daily feed intake of the piglets decreased, and the feed-to-weight ratio increased, indicating that the glucuronolactone in a specific content range in the feed of the present invention has the effect of improving the growth performance of PRRSV-infected piglets, and excessive glucuronolactone content in the feed will affect the growth performance of the piglets.

[0077] Test Example 2

[0078] The effect of feed on the growth performance of DON-infected piglets was tested as follows:

[0079] 40 21-day-old weaned piglets with an average weight of 7.20±0.21 kg were selected and divided into 4 groups. They were fed with the feeds in Examples 1 and 3 and Comparative Examples 3 and 4, respectively. 2 mg / kg of DON was added to the feeds of the 4 groups to infect the piglets with DON. The piglets were fed 4 times a day and were free to eat. After 36 days of feeding, the growth performance of the DON-infected piglets was tested. The test results are shown in Table 2.

[0080] Table 2

[0081] Average daily weight gain (g / d) Average daily feed intake (g / d) Material weight ratio Example 1 443 612 1.38 Example 3 472 667 1.41 Comparative Example 3 395 574 1.45 Comparative Example 4 419 603 1.44

[0082] From the results in Table 2, it can be seen that in Comparative Example 3, after an equal amount of glucuronolide was replaced with amoxicillin, the average daily weight gain and average daily feed intake of DON-infected piglets decreased, and the feed-to-weight ratio increased, indicating that the glucuronolide in the feed of the present invention can improve the growth performance of DON-infected piglets.

[0083] In Comparative Example 4, after the addition amount of glucuronolactone in the feed was set to 1g, the average daily weight gain and average daily feed intake of DON-infected piglets decreased, and the feed-to-weight ratio increased, indicating that the glucuronolactone in a specific content range in the feed of the present invention has the effect of improving the growth performance of DON-infected piglets, and that too high a glucuronolactone content in the feed will affect the growth performance of the piglets.

[0084] Test Example 3

[0085] The effect of feed on the growth performance of piglets co-infected with PRRSV and DON was tested as follows:

[0086] 80 21-day-old weaned piglets with an average body weight of 7.41±0.15 kg were selected and divided into 8 groups. The feeds in Examples 1, 2, 4, 5 and Comparative Examples 1, 2, 5, and 6 were fed respectively. 2 mg / kg of DON was added to the feeds of the 8 groups to infect the piglets with DON. The piglets were fed 4 times a day and were free to eat. On the 15th day of feeding, all piglets were injected with 2.0 ml of PRRSV (10 5 TCID 50 / ml) to infect piglets with PRRSV, and after 3 weeks of continuous feeding, the growth performance of piglets co-infected with PRRSV and DON was tested. The test results are shown in Table 3.

[0087] Table 3

[0088] Average daily weight gain (g / d) Average daily feed intake (g / d) Material weight ratio Example 1 445 623 1.4 Example 2 451 629 1.39 Example 4 487 672 1.38 Example 5 482 664 1.38 Comparative Example 1 332 512 1.54 Comparative Example 2 327 507 1.55 Comparative Example 5 325 498 1.53 Comparative Example 6 314 482 1.54

[0089] From the results in Table 3, it can be seen that in Comparative Example 1, after the glucuronolide in the feed of Example 2 was replaced with ribavirin in an equal amount, and in Comparative Example 2, after the glucuronolide in the feed of Example 4 was replaced with ribavirin in an equal amount, the average daily weight gain and average daily feed intake of piglets co-infected with PRRSV and DON were both reduced, and the feed-to-weight ratio was increased, indicating that the glucuronolide in the feed of the present invention can improve the growth performance of piglets co-infected with PRRSV and DON.

[0090] In Comparative Example 5, the amount of glucuronolactone added in the feed of Example 2 was set to 1g, and in Comparative Example 6, the amount of glucuronolactone added in the feed of Example 4 was set to 1g. The average daily weight gain and average daily feed intake of piglets co-infected with PRRSV and DON decreased, and the feed-to-weight ratio increased, indicating that the glucuronolactone within a specific content range in the feed of the present invention has the effect of improving the growth performance of piglets co-infected with PRRSV and DON, and that too high a content of glucuronolactone in the feed will affect the growth performance of infected piglets.

[0091] Test Example 4

[0092] The effects of feed on other parameters of piglets co-infected with PRRSV and DON were tested as follows:

[0093] Thirty 21-day-old weaned piglets with an average body weight of 7.41±0.15 kg were selected and randomly divided into three groups, with 10 pigs in each group (raised in the same pen).

[0094] The first group was a control group (CON) infected with PRRSV, the second group was a DON group infected with PRRSV and DON, and the third group was a DON+GLU group infected with PRRSV and DON using glucuronolactone. The infection method of the first group of piglets was referred to the above test example 1, and the infection methods of the second and third groups of piglets were referred to the above test example 3.

[0095] The three groups of piglets were fed with feeds as follows: the CON group piglets were fed with the feed in Example 4 without glucuronolide, the DON group piglets were fed with the feed in Example 4 without glucuronolide, and the DON+GLU group piglets were fed with the feed in Example 4. The feeding method was referred to Test Example 3.

[0096] After 36 days of feeding, all piglets were slaughtered and sampled to test the following indicators:

[0097] 1. Body temperature and clinical symptoms of piglets: After PRRSV infection, piglets in the CON group showed typical clinical symptoms such as elevated body temperature, rapid breathing, coughing, lethargy, loss of appetite, slow reaction, and swollen eyelids. Compared with piglets in the CON group, piglets in the DON group showed more obvious symptoms, with more severe symptoms in terms of nasal secretions, eye secretions, and conjunctival edema. Compared with piglets in the DON group, piglets in the DON+GLU group had milder clinical symptoms and slower disease progression, especially in terms of respiratory symptoms such as respiratory rate, coughing, and sneezing. This indicates that eating feed contaminated with DON will aggravate the symptoms of PRRSV infection, and the glucuronolactone contained in the feed can effectively alleviate the infection symptoms of piglets co-infected with PRRSV and DON.

[0098] 2. Organ index. The results are shown in Table 4.

[0099] Table 4

[0100] project CON DON DON+GLU P-value heart 0.57±0.02 0.56±0.01 0.53±0.01 0.246 liver <![CDATA[3.72±0.06 ab ]]> <![CDATA[3.81±0.13 a ]]> <![CDATA[3.39±0.14 b ]]> 0.055 spleen 0.27±0.02 0.28±0.02 0.26±0.02 0.685 lung <![CDATA[1.87±0.11 b ]]> <![CDATA[2.54±0.14 a ]]> <![CDATA[1.41±0.06 c ]]> 0.001 kidney <![CDATA[0.57±0.03 ab ]]> <![CDATA[0.63±0.02 b ]]> <![CDATA[0.59±0.01 a ]]> 0.130

[0101] Note: Different lowercase letters in the same row indicate significant differences (P<0.05); the same or no letters indicate no significant differences (P>0.05).

[0102] As shown in Table 4, after PRRSV infection, the lung organ index of the DON group increased significantly compared with the CON group piglets, indicating that the combined infection of PRRSV and DON aggravated the symptoms of the lung organs. Compared with the DON group piglets, the lung, liver and kidney organs of the DON+GLU group decreased significantly, indicating that the glucuronolactone in the feed significantly alleviated the symptoms of the lung, liver and kidney organs.

[0103] 3. Lung tissue morphology, the results are as follows Figure 1 , Figure 2 shown.

[0104] Depend on Figure 1It can be seen that after PRRSV infection, compared with the piglets in the CON group, the piglets in the DON group had more severe lung damage, which was characterized by darker color, enlarged lesions and obvious congestion, and the pathological score was significantly increased, indicating that the co-infection of PRRSV and DON would aggravate the lung damage of the infected piglets; compared with the piglets in the DON group, the severity of lung lesions in the DON+GLU group was significantly reduced, the consolidation area was small and the bleeding points were fewer, and the pathological score was significantly reduced, indicating that the glucuronolactone contained in the feed can effectively reduce the lung damage of piglets co-infected with PRRSV and DON.

[0105] Depend on Figure 2 It can be seen that after PRRSV infection, compared with the piglets in the CON group, the lung damage of the piglets in the DON group was aggravated, manifested by moderate thickening of the alveolar wall, enlarged alveolar septa and infiltration of inflammatory cells, and the pathological score was increased, indicating that the co-infection of PRRSV and DON would aggravate the lung damage of the infected piglets; compared with the piglets in the DON group, the granulocyte infiltration of the alveolar wall of the piglets in the DON+GLU group was reduced, a small amount of bleeding was seen around the bronchioles and blood vessels, and the pathological score was significantly reduced, indicating that the glucuronolactone contained in the feed can effectively reduce the lung damage of piglets co-infected with PRRSV and DON.

[0106] 4. Serum and lung viral load, the results are as follows Figure 3 As shown: After PRRSV infection, the serum and lung viral loads of piglets in the DON group were significantly increased compared with those in the CON group, indicating that the co-infection of PRRSV and DON would increase the viral load of PRRSV in the serum and lungs of piglets; compared with the piglets in the DON group, the serum viral load of piglets in the DON+GLU group was significantly decreased, indicating that the glucuronolactone contained in the feed can effectively reduce the viral load of the serum and lungs of piglets co-infected with PRRSV and DON.

[0107] 5. Lung inflammation, the results are as follows Figure 4 As shown: after PRRSV infection, compared with the piglets in the CON group, the mRNA expression level of TNF-α (tumor necrosis factor α) in the DON group piglets was significantly increased, and the mRNA expression level of IFN-α (interferon α) was significantly decreased, indicating that the co-infection of PRRSV and DON would aggravate the lung inflammation of the infected piglets; compared with the piglets in the DON group, the mRNA expression of IL-6 (interleukin 6) and TNF-α in the DON+GLU group piglets was significantly decreased, and the mRNA expression level of IL-10 (interleukin 10) was significantly increased, indicating that the glucuronolactone contained in the feed can effectively control the inflammatory response in the lungs of piglets co-infected with PRRSV and DON.

[0108] 6. Antioxidant capacity, the results are as follows Figure 5 , Figure 6 , Figure 7 shown.

[0109] Depend on Figure 5 It can be seen that after PRRSV infection, compared with piglets in the CON group, the MDA (malondialdehyde) level in the plasma of the DON group was significantly increased, and the CAT (catalase) and T-AOC (total antioxidant capacity) levels were significantly decreased; compared with piglets in the DON group, the CAT, SOD (superoxide dismutase) and T-AOC levels in the plasma of piglets in the DON+GLU group were significantly increased, and the MDA level was significantly decreased. Compared with piglets in the CON group, the MDA level in the lungs of piglets in the DON group was significantly increased; compared with piglets in the DON group, the MDA level in the lungs of piglets in the DON+GLU group was significantly decreased, and the SOD and T-AOC levels were significantly increased. This shows that compared with PRRSV infection alone, the co-infection of PRRSV and DON will further reduce the antioxidant capacity of infected piglets, and the glucuronolactone contained in the feed can effectively improve the antioxidant capacity of piglets co-infected with PRRSV and DON.

[0110] Depend on Figure 6 It can be seen that after PRRSV infection, the mRNA expression level of NQO-1 gene in the lungs of piglets in the DON group was significantly decreased compared with that in the CON group, indicating that the co-infection of PRRSV and DON would further reduce the antioxidant capacity of infected piglets; compared with the DON group, the mRNA expression levels of antioxidant enzyme-related genes SOD1, GCLM, HO-1, NQO-1 and HMOX in the lungs of the DON+GLU group were significantly upregulated, indicating that the glucuronolactone contained in the feed can effectively improve the antioxidant capacity of piglets co-infected with PRRSV and DON.

[0111] Depend on Figure 7 It can be seen that the Nrf2 signaling pathway is the key to regulating oxidative stress. After PRRSV infection, compared with piglets in the CON group, the levels of P-Nrf2 / Nrf2 and HO-1 proteins in the lungs of piglets in the DON group were significantly reduced, while the expression of Keap1 protein was significantly increased, indicating that the co-infection of PRRSV and DON would further reduce the antioxidant capacity of infected piglets; compared with piglets in the DON group, the levels of P-Nrf2 / Nrf2 and HO-1 proteins in the lungs of the DON+GLU group were significantly upregulated, while the expression of Keap1 protein was significantly decreased, indicating that the glucuronolactone contained in the feed can significantly improve the antioxidant capacity of piglets co-infected with PRRSV and DON through the Nrf2 signaling pathway.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Application of glucuronolactone in the preparation of feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection.

2. The use according to claim 1, characterized in that: Based on the mass of the feed, the effective amount of glucuronolactone added to the feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection is 50-600 mg / kg.

3. A feed for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection, characterized in that: The invention comprises a basic feed and glucuronolactone for preventing and treating PRRSV infection, DON infection, or PRRSV and DON combined infection.

4. The feed according to claim 3, characterized in that The basic feed comprises the following components: corn, protein substances, low-protein whey powder, oil, sugar, amino acid, feed additives, enzyme preparations and premixes.

5. The feed according to claim 4, characterized in that Calculated by weight of the feed, the feed contains the following components: 450-650 parts of corn, 250-350 parts of protein substances, 40-80 parts of low-protein whey powder, 15-35 parts of oils and fats, 10-30 parts of sugars, 3.2-7.6 parts of amino acids, 5.5-10 parts of feed additives, 1-3 parts of enzyme preparations, and 10-30 parts of premixes; calculated by weight of the feed, the added amount of glucuron-lactone is 50-600 mg / kg.

6. The feed according to claim 4 or 5, characterized in that The protein substances are soybean meal, puffed soybeans and fish meal; and / or the mass ratio of the soybean meal, puffed soybeans and fish meal is (150-190): (80-115): (20-45).

7. The feed according to claim 4 or 5, characterized in that The amino acids are lysine, threonine and methionine.

8. The feed according to claim 7, characterized in that The mass ratio of lysine, threonine and methionine is (2-4.2):(0.6-1.7):(0.6-1.7).

9. The feed according to claim 4 or 5, characterized in that The feed additives are calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride; and / or the mass ratio of calcium hydrogen phosphate, stone powder, salt, zinc oxide and choline chloride is (0.8-1.5):(0.2-0.8):(2.0-3.5):(1.2-1.8):(1.3-2.4).

10. The feed according to claim 4 or 5, characterized in that The enzyme preparation is a mixture of lipase and amylase.

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