Alternative antibiotic feed additives alleviate pneumonia with inhibiting ACE‐2 expression in the respiratory system of piglets

Abstract

Weaning piglets often suffer from pneumonia during growth, so in general, antibiotics are used by owners to make piglets grow smoothly. However, antibiotics may be accompanied by many side effects such as gastrointestinal discomfort and allergies. The aim of this study was to develop an alternative antibiotic herbal veterinary medicine for alleviating pneumonia in weanling piglets. As observed in the pig ranches, many weanling piglets suffer from the pneumonia and also show high expression of angiotensin‐converting enzyme 2 (ACE‐2) in their respiratory and intestinal tracts. ACE inhibitors have been reported that can decrease pneumonia risk through their main mechanism of action. Thus, we also try to find alternative antibiotic feed additives that can reduce expression of ACE‐2 in piglets. We selected the Guizhi Li‐Zhong Tang Extract Granules (GLZ) as a natural product for piglets. Then, we compared the serum immunoglobulin levels of piglets with sham, tilmicosin antibiotic (TAB), and GLZ treatments. Our results showed that piglets with GLZ treatment had significantly a higher expression of immunoglobulin A and immunoglobulin G but a lower expression of immunoglobulin E than those with sham and TAB treatments. In addition, piglets with GLZ treatment showed obviously low pneumonia incidence than those with sham and TAB treatments. Similarly, piglets with GLZ treatment showed significantly lower expressions of ACE‐2 in their tracheal, bronchial, and lung tissues than those with sham and TAB treatments. GLZ seems to be an alternative ACE inhibitor that can decrease pneumonia risk through inhibiting ACE‐2 expression and alleviating allergies in their respiratory systems. Thus, we suggest that GLZ can be an alternative antibiotic feed additive for weaning piglets.

Evaluation of Tannin Extracts, Leonardite and Tributyrin Supplementation on Diarrhoea Incidence and Gut Microbiota of Weaned Piglets

“…In fact, following the ban on the use of antibiotics as growth promoters, therapeutic antibiotics and zinc oxide have become more widely used [7][8][9] to prevent porcine colibacillosis, improve suboptimal weight gain, and feed efficiency. Alternatives to antibiotics and zinc oxide are also urgently needed to guarantee the profitability of swine farming, particularly during weaning, which involves the largest use of antimicrobials due to the high incidence of gastroenteric disorders and multifactorial post-weaning diarrhoea (PWD) [10,11]. The gastrointestinal tract (GIT) is a highly specialised organ where the dynamic interaction between host cells and the complex environment (mucosal chemical barrier, immune system, and epithelium) impacts on gut health [12].…”

Chinese Herbal Medicine Formula Guizhi Li-Zhong Tang as an Alternative to Antibiotic Feed Additives for Preventing Pneumonia in Piglets through Antioxidant, Anti-Inflammatory, and Antiapoptotic Protection

“…The herbal formula GLZ was investigated as an alternative medicine for weanling piglets. The formula can alleviate respiratory allergies and prevent pneumonia in weanling piglets by inhibiting ACE-2 expression in the respiratory system [ 20 ]. However, little is known regarding the underlying pharmacological mechanisms.…”

“…A component of GLZ, Guizhi, is a traditional herbal preparation that has been used to treat head-related illnesses such as fever, headache, sweating, and wind-induced headaches [ 22 ]. Chromatographic investigation of Guizhi in our previous research [ 20 ] revealed that its bioactive substances are coumarin, cinnamic acid, cinnamaldehyde, and 2-methoxycinnamaldehyde. Coumarin has been used in various products and candidate drugs because coumarin compounds have high bioavailability and both antioxidant and anti-inflammatory properties [ 23 ].…”

“…The medicinal ingredients in weight percentage are as follows: Guizhi 5–40%, Ginseng 10–25%, licorice 10–25%, Atractylodes macrocephala 10–35%, and ginger 10–25%. As our previous study [ 20 ], we analyzed bioactive marker compounds of GLZ through three-dimensional chromatography.…”

“…In patients with COVID-19, high ACE-2 expression was identified in lung alveolar cells, and some patients had severe pneumonia [ 19 ]. We previously discovered that Guizhi Li-Zhong Tang (GLZ) could be used as an alternative feed additive to significantly reduce ACE-2 expression in the lung tissue of piglets as compared with sham or antibiotic treatments [ 20 ]. Although GLZ can be used to treat pneumonia in weanling piglets by reducing ACE-2 expression in lung tissue, the related protective mechanisms have not been studied systematically.…”