NUTRITION ▶▶▶


Oyster mushrooms: A diarrhoea remedy


The feed industry is focusing on alternatives to reduce the use of antibiotics as growth promoters and zinc oxide as a diarrhoea remedy in piglet diets. Thanks to its immunomodulation properties, among other properties, oyster mushroom is one of the potential alternatives.


BY MATTHEW WEDZERAI, CORRESPONDENT Z Parameter (mmol/L) Acetate


Propionate Butyrate


Total SCFA 22


inc oxide (ZnO) is usually recommended for inclu- sion during the first two weeks after weaning to prevent post-weaning diarrhoea in pigs. However, due to its low absorption, most ZnO is excreted in


faeces, which is detrimental to the environment. Whereas therapeutic ZnO is not approved for use in the EU as from 2022, antibiotics are an alternative to the control of Escheri- chia coli infections post-weaning. However, these antibiotics are being banned due to their ef- fects on antimicrobial resistance. In humans, several studies (involving animal models) have shown that edible mush- rooms have immunomodulating properties, including β-glu- can-induced anti-inflammatory effects, enhanced natural kill- er (NK) cell activity, improved dendritic cell maturation and function and increased cytokine production in patients with ulcerative colitis and Crohn’s disease. Mushrooms contain secondary metabolites such as alkaloids, lactones, polyphe- nols, sesquiterpenes, sterols, terpenoids, β-glucans and


Table 1 – Concentration of acetate, butyrate, propionate and total SCFA of weaning piglets fed diets containing different levels of oyster mushroom.


Dietary OM levels (g/kg)


0.00 5.00 10.00 15.00 35.95 45.37 49.83 42.96 11.17 25.12 24.30 22.98 9.13 10.39 11.14 13.35 56.25 80.88 85.27 79.29


▶PIG PROGRESS | Volume 36, No. 6, 2020


glycoproteins. These metabolites are responsible for immu- nomodulation and have anticholesterolemic, anticancer and antioxidant properties.


Diarrhoea incidence Researchers at Jilin Agricultural University, Changchun, China, found valuable effects of supplementing piglet diets with oyster mushrooms. The mushrooms were included in three doses: 5g/kg, 10g/kg and 15g/kg. A total of 100 crossbred (Duroc×Large White×Landrace) weaner piglets were used. The inclusion of mushroom at 5g/kg feed resulted in a 51% lower incidence of diarrhoea compared to the control group, and 15g/kg resulted in a 55% lower incidence of diarrhoea. The researchers attributed the reduction to the presence of bioactive compounds such as glucans, alkaloids, phenols and other active ingredients that can reduce the enteric bacteria (coliform, E. coli, etc.) population and activities in the intes- tines of piglets. The prebiotic properties of this mushroom re- sulted in high production of short chain fatty acids (SCFAs) such as butyrate, propionate and acetate. The bacteriostatic properties of butyrate result in a better immune response and a heathier gut – contributing to a reduction in the incidence of diarrhoea.


Gut microflora Their findings showed that supplementing the diet with oys- ter mushrooms increased intestinal microbial population and diversity. The most abundant microbes in the treated groups were the Bacteroidetes phylum (which mainly produces ace- tate and propionate) and the Firmicutes phylum (for butyrate production). The high fibre content of mushrooms is less digestible in the upper gastrointestinal tract (GIT) as it lacks fibre-digesting enzymes. However, microbes in the large intestine can fer- ment these fibres to synthesise SCFAs such as acetate, bu- tyrate and propionate. These SCFAs lower the hindgut pH, creating unfavourable conditions for most pathogenic bacte- ria – thus promoting gut health. Butyrate also serves as the main source of energy for colonocytes, helping with the maintenance of gut homeostasis and intestinal epithelial in- tegrity; its bacteriostatic properties help improve the immune response. Their study has shown that oyster mushrooms act as a prebiotic that favourably affects the composition and


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