Epsilon Archive for Student Projects

Abstract

Aquaculture is one of the fastest-growing food-production industries worldwide accounting for almost half of fish used for human consumption. Super-intensive, intensive, and semi-intensive farming practices used to produce large farm fish are increasing the frequency of disease outbreaks which is a major problem affecting sustainable aquaculture growth. Antibiotics used to overcome disease have led to the development of resistant strains which is becoming a global public concern. Over the past few years, there has been a growing interest in using plant-derived nutraceuticals, especially those that possess heat shock protein Hsp70-inducing bioactivities as an alternative to antibiotics. In this study using brine shrimp Artemia as a model organism, an Asian ginseng extract (referred to as Ash01) was studied to examine it’s potential as an Hsp70 inducer for controlling diseases in aquaculture animals. First, a range-finding test for the extract was carried out in Artemia and was found between 200 and 1000 mg/l. Using this dose range, subsequent studies were conducted to determine whether the extract could confer protection to the host Artemia against an aquaculture pathogen Vibrio campbellii LMG 21363, or a wide range of abiotic stressors. Results showed that pre-treatment of Artemia nauplii with Ash01 at a dose of 1000 mg/l caused a significant improvement in the resistance of the nauplii towards pathogenic V. campbellii challenge as well as towards a wide range of environmental stressors like thermal shock, salinity stress, and low pH. This salutary effect of Ash01 appeared to be associated with an increase in the level of heat shock protein Hsp70 and/or possibly other family members of stress proteins. An upregulation of hsp70 gene by a fold of 3.6 although was observed in the Ash01-treated group. The increase however was not significantly different from the untreated control group. Further studies should be carried out using an extract from Ash01 to analyze Hsp70 both at the gene and protein levels as it is likely that the production of Hsp70 in response to Ash01 pre-treatment in Artemia occurred at the protein level. Overall results add new information about the functional properties of Ash01 and advance our knowledge of this herbal plant as a potential prophylactic agent for controlling infection stress in aquaculture animals.