Screening of probiotics from indigenous Omani natural products for potential use in the aquaculture industry

Abstract

Probiotics can enhance the growth performance and disease resistance of aquatic animals. Probiotics can influence digestive physiology through the secretion of exogenous digestive enzymes, facilitating the utilization of nutrients, and resulting in improvements in growth performance. The objectives of the present study were to reduce fish diseases, minimize the usage of antibiotics, and promote national policy on aquatic health management in Oman through enhancing immune stimulation mechanisms with probiotics from indigenous Omani products and finally to promote Oman’s aquaculture industry. Thirty-five kinds of edible products were screened. After the primary screening process, only 3 products contained appropriate amounts of probiotics, therefore the present study focused on 3 probiotics from Omani products, i.e., dried date, date vinegar, and camel milk. Gram staining, VITIK2, and DNA tests were used for the identification and characterization of bacterial strains. DNA sequence revealed that the bacteria isolated from dried dates were identified as Bacillus licheniformis. Those from date vinegar were identified as Bacillus vallismortis. A viability test with pepsin, pH 3 showed that the bacteria isolated from camel's milk (Bacillus stratospheric) had a greater tolerance at low pH followed by bacteria isolated from dried date (B. licheniformis). Thus, these can be used as a probiotic for aquatic organisms.