Use of lysophosphatidic acid in prevention and treatment of porcine infectious diarrhea

Abstract

A method for preventing and treating porcine infectious diarrhea, wherein lysophosphatidic acid is used as a feed additive for preventing and treating porcine infectious diarrhea, and the porcine infectious diarrhea is caused by Escherichia coli. The feed additive is a premix prepared by means of mixing lysophosphatidic acid and a carrier, and the dosage form thereof is an oral powder or granule, and the dosage of the lysophosphatidic acid premix added to the feed is 0.1%-0.5% of the total weight of the feed.

Description

Application of lysophosphatidic acid in preventing and treating infectious diarrhea in pigs Technical Field

[0001] The invention belongs to the technical field of feed nutrition and relates to application of lysophosphatidic acid as a feed additive in preventing and treating infectious diarrhea in pigs. Background Art

[0002] Early weaning of piglets is a key technology in modern intensive pig farming. It effectively shortens the sow's lactation period, increases annual productivity, and maximizes reproductive performance. However, early weaning deprives piglets of the passive immunity provided by their mother's breast milk, reducing their immunity and making them susceptible to exogenous pathogens, leading to decreased disease resistance. Furthermore, the piglet's gastrointestinal tract is not fully developed at the time of early weaning. Weaning also causes structural changes in the intestinal morphology, including shortened villi, increased crypt depth, and decreased digestive enzyme activity. These gastrointestinal changes impair the piglet's ability to digest and absorb dietary nutrients. Undigested nutrients enter the posterior intestinal tract and ferment, allowing pathogens to multiply and proliferate, reducing the number of beneficial bacteria and increasing the number of harmful bacteria, thereby compromising the intestinal barrier. Furthermore, increased intestinal permeability allows exogenous and exogenous pathogens to easily penetrate the intestinal epithelium, triggering symptoms such as intestinal inflammation and diarrhea.

[0003] E. coli can be divided into two main categories, enterotoxigenic and non-toxigenic, based on their ability to produce enterotoxins during infection. Enterotoxigenic E. coli (ETEC) is the most common pathogen causing intestinal diseases in livestock and poultry, and a major cause of mortality in piglets. ETEC relies on adhesion factors to colonize host intestinal epithelial cells. Their massive proliferation disrupts the intestinal microbiome, triggering secondary infections. ETEC also secretes enterotoxins, disrupting the osmotic pressure of intestinal epithelial cells and impairing intestinal barrier function, leading to intestinal dysfunction, diarrhea, dehydration, and even death in piglets. ETEC-infected piglets initially bind to the host intestinal epithelium through adhesins. Currently, the most studied animal-derived ETEC adhesins include K88 (F4), K99 (F5), and 987P (F6), with K88 (F4) garnering the most attention. K88 mainly includes three serotypes: K88ab, K88ac, and K88ad. K88ac is considered to be the main serotype that causes diarrhea in piglets. The immune response caused by ETEC K88ac infecting piglet intestinal epithelial cells (IPEC-J2) is the most obvious. After colonizing the small intestine, ETEC will proliferate rapidly and secrete virulence factors such as enterotoxins that are directly related to diarrhea, including heat-labile enterotoxins (LT) and heat-stable enterotoxins (ST). The heat-stable enterotoxin (ST) secreted by porcine ETEC can bind to the extracellular domain and sulfolipid receptors of guanylate cyclase C (GC-C) of porcine intestinal epithelial cells, leading to an imbalance in water and salt metabolism in the intestine, extravasation of large amounts of water and electrolytes, and causing secretory diarrhea.

[0004] In production, when piglets develop diarrhea caused by E. coli, antibiotics are often used to treat them. However, while treating diarrhea, antibiotics can also cause toxic side effects such as reduced immunity, increased bacterial resistance, the presence of drug residues, and gene mutations, deformities, and cancer.

[0005] Lysophosphatidic acid (LPA) is a biologically active glycerophospholipid with high concentrations in serum but low concentrations in other eukaryotic tissues. LPA is known to have at least six high-affinity, homologous rhodopsin-like G-protein coupled receptors, as well as a nuclear receptor and peroxisome proliferator-activated receptor C (PPARc). The biological effects of LPA can be divided into three categories: normal cell function, such as smooth muscle contraction, cell chemotaxis, Ca 2+ Mobilization and neurotransmitter release, platelet aggregation, erythropoiesis, hematopoietic function of bone marrow stroma, normal cell proliferation and migration, cell differentiation, etc.; secondly, inhibiting various diseases, including schizophrenia, atherosclerosis, abnormal itching, asthma, fibrosis, reproductive disorders and bone metabolism; thirdly, regulating the acquisition of malignant capabilities of many cancer cell lines, such as abnormal proliferation and migration, infection, autophagy, and drug resistance of cancer cells.

[0006] Summary of the Invention

[0007] The present invention aims to provide a method for using lysophosphatidic acid as a feed additive in preventing and treating infectious diarrhea in pigs. Lysophosphatidic acid (sodium 1-oleoyl-sn-glycerol 3-phosphate) has a molecular weight of 510.39 and a structure as follows:

[0008] Preferably, the porcine infectious diarrhea is caused by Escherichia coli.

[0009] More preferably, the feed additive is in the form of powder or granules.

[0010] More preferably, the feed additive is a composition or mixture containing an effective dose of lysophosphatidic acid.

[0011] More preferably, the feed additive composition is a premix prepared by mixing lysophosphatidic acid and a carrier.

[0012] More preferably, the amount of the lysophosphatidic acid premix added to the feed is 0.1% to 0.5% of the total weight of the feed.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] Lysophosphatidic acid is a lipid substance produced endogenously in the body. It can reduce the excessive secretion of intestinal fluid in piglets infected with E. coli by inhibiting CFTR-dependent iodine efflux. It also helps prevent susceptibility to E. coli in weaned piglets, effectively maintaining intestinal health. Lysophosphatidic acid, an endogenous substance, is the first to be discovered in this study to prevent and treat E. coli-induced diarrhea in piglets, without toxic side effects, and with no environmental impact from animal excretion. DETAILED DESCRIPTION

[0015] Example 1

[0016] 1. Test materials

[0017] The average weight of 25-day-old DLY weaned piglets was (7.24±0.07) kg.

[0018] 2. Experimental Design

[0019] The study involved 32 piglets divided into four groups, with eight replicates in each group, for a 21-day trial. The ETEC+LPA and LPA groups received 0.3% lysophosphatidic acid in their diets. On day 18, the control and LPA groups were gavage-fed 500 ml of normal saline, while the ETEC and ETEC+LPA groups were gavage-fed 500 ml of ETEC solution, with an ETEC concentration of 1 × 10 9CFU concentration. Specific grouping is shown in Table 1. Slaughter sampling was carried out on the morning of the 21st day of the experiment.

[0020] Table 1 Experimental groups

[0021] 3. Test results

[0022] 3.1 Effect of lysophosphatidic acid on the rate of Escherichia coli infectious diarrhea in piglets

[0023] As shown in Table 2, ETEC challenge significantly increased the diarrhea rate and diarrhea index of piglets (P < 0.05). Adding LPA to the feed significantly improved ETEC-induced diarrhea in piglets, significantly reducing the diarrhea rate (P < 0.05) and diarrhea index (P < 0.05).

[0024] Table 2 Effects of adding LPA to feed on diarrhea indicators in piglets after virus challenge Note: Data in the same row without letters or with the same letters indicate no significant difference (P>0.05), while data with different lowercase letters indicate significant difference (P<0.05).

[0025] 3.2 Effects of lysophosphatidic acid on intestinal tissue morphology in piglets infected with Escherichia coli

[0026] As shown in Table 3, there were no significant differences in villus height, crypt depth, or villus height / crypt depth ratio (V / C) between the CON and LPA groups (P>0.05). ETEC challenge decreased villus height and V / C in the duodenum and ileum (P<0.05) and increased crypt depth in the ileum (P<0.05). Dietary LPA significantly increased villus height and V / C in the duodenum and ileum of ETEC-challenged piglets (P<0.05). Furthermore, LPA decreased crypt depth and increased the villus / crypt ratio in the ileum of ETEC-challenged piglets (P<0.05).

[0027] Table 3 Effects of LPA supplementation in feed on intestinal tissue morphology of piglets

[0028] 3.3 Effect of lysophosphatidic acid on intestinal permeability of piglets infected with Escherichia coli

[0029] As shown in Table 4, compared with the CON group, the LPS, DAO, D-lactic acid, and fluid aggregation rate of ETEC-challenged piglets increased significantly (P < 0.05), and the addition of LPA to the feed significantly reduced the LPS, DAO, D-lactic acid, and fluid aggregation rate of ETEC-challenged piglets (P < 0.05).

[0030] Table 4 Effect of LPA addition in feed on the permeability of piglets after challenge

[0031] 4. Conclusion

[0032] Lysophosphatidic acid has no significant negative impact on the growth performance of piglets, can significantly improve the damage to the intestinal tissue morphology and the reduction in permeability caused by ETEC in piglets, and can significantly reduce the diarrhea rate caused by Escherichia coli in piglets.

[0033] Example 2

[0034] 1. Test materials

[0035] The average weight of 21-day-old DLY weaned piglets was (6.23±0.82) kg.

[0036] 2. Experimental Design

[0037] The experiment involved 24 piglets divided into three groups, with eight replicates in each group, for a 21-day trial. The ETEC+LPA group received 0.2% lysophosphatidic acid in their diet. On day 18, the control group received 200 ml of normal saline, while the ETEC and ETEC+LPA groups received 200 ml of ETEC solution, with an ETEC concentration of 1 × 10 9 CFU concentration. Specific grouping is shown in Table 5. Slaughter sampling was carried out on the morning of the 21st day of the experiment.

[0038] Table 5 Experimental groups

[0039] 3. Test results

[0040] As shown in Table 6, the addition of lysophosphatidic acid before infection significantly reduced the diarrhea rate (P < 0.05). At the same time, after infection, the diarrhea rate and diarrhea index of E. coli-infected piglets supplemented with lysophosphatidic acid also decreased significantly (P < 0.05).

[0041] Table 6 Escherichia coli diarrhea rate in piglets

[0042] 4. Conclusion

[0043] Adding 0.2% lysophosphatidic acid to feed can effectively reduce the diarrhea rate caused by Escherichia coli in weaned piglets.

[0044] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preventing and treating infectious diarrhea in pigs, characterized in that: Lysophosphatidic acid is used as a feed additive to prevent and treat infectious diarrhea in pigs.

2. The method according to claim 1, characterized in that The porcine infectious diarrhea is caused by Escherichia coli.

3. The method according to claim 1 or 2, characterized in that: The feed additive is in the form of oral powder or granules.

4. The method according to claim 1 or 2, characterized in that: The feed additive is a composition or mixture containing an effective dose of lysophosphatidic acid.

5. The method according to claim 4, characterized in that The feed additive composition is a premix prepared by mixing lysophosphatidic acid and a carrier.

6. The method according to claim 5, characterized in that The addition amount of the lysophosphatidic acid premix in the feed is 0.1% to 0.5% of the total weight of the feed.

Images