SilvaFeed ENC (S-ENC) is a natural vegetable extract used in the animal feed
industry that provides the animal diet with natural elements. Avian reoviruses
(ARV) are RNA viruses members of the Orthoreovirus genus, Reoviridae
family. ARVs are important causes of disease in poultry, in particular viral
arthritis. It is sometimes associated with chronic respiratory diseases and
Malabsorption syndrome (MAS) together with different enteric viruses including
rotavirus, enterovirus, calicivirus and others. Signs of MAS include anorexia,
diarrhoea, dehydration, growth depression and weight loss, which can lead to
mortality. Considerable economic losses follow the Malabsorption syndrome.
Purpose: Field evidence had previously suggested that this substance could
be effective against enteric viral infectious. In this work we evaluated the in
vitro activity of S- ENC against ARV.
Methods: An ARV strain (R2), isolated in United Kingdom in 1980 was used.
The S-ENC antiviral activity against ARV was tested before and after the
adsorption of the ARV to VERO cells, in order to evaluate the presence of an
intra- or an extra-cellular antiviral activity. The inhibitory effect of S-ENC was
expressed as IC50 (concentration of the compound corresponding to 50%
inhibition of viral cytopathic effect). The MTT assay has been used to evaluate
the 50% cytotoxic concentration (CC50) in the presence of S-ENC on the
growth of VERO cells.
Results: The CC50 of S-ENC was 243,0 ± 18,4 μg/ml and the IC50 in the intracellular
antiviral assay was >200 μg/ml. However S-ENC showed an
extracellular antiviral activity IC50 of 54,2 ± 14,4 μg/ml. All results represented
the mean ± standard deviation of three independent experiments.
Conclusion: S-ENC had in vitro a low cytotoxicity and an extracellular antiviral
activity. Therefore these preliminary results suggests that SilvaFeed ENC
could be a good means in the control of Malabsorption syndrome.
Nevertheless, further in vivo experiments are required to confirm these
findings.
