In vitro and in vivo selection of probiotic purple nonsulphur bacteria with an ability to inhibit shrimp pathogens: acute hepatopancreatic necrosis disease-causing Vibrio parahaemolyticus and other vibrios

Abstract

Shrimp cultivation has been faced with huge losses in productivity caused by infectious shrimp pathogenic vibrios, especially Vibrio parahaemolyticus that causes acute hepatopancreatic necrosis disease (AHPND). Hence, purple nonsulphur bacteria (PNSB) were isolated from shrimp ponds for investigating their abilities to control shrimp pathogenic Vibrio spp. and their use as probiotics for sustainable shrimp cultivation. Based on their probiotic properties, strains S3W10 and SS15 were selected because of their strong abilities to produce amylase, gelatinase and vitamin B12. However, only three PNSB strains (SS15, TKW17 and STW181) strongly inhibited V. harveyi_KSAAHRC and V. vulnificus_KSAAHRC including V. parahaemolyticus AHPND strains by secreting antivibrio compounds. Four selected PNSB also grew in the presence of pancreatic enzymes, and they were identified as Rhodobacter sphaeroides for strains S3W10, SS15 and TKW17 and Afifella marina for strain STW181. The effects of a mixed culture were also investigated as follows: T1 (S3W10 + SS15), T2 (S3W10 + TKW17) and T3 (S3W10 + STW181) on postlarval white shrimp (Litopenaeus vannamei) for 60 days by comparison with a control. All three probiotic PNSB sets significantly improved the digestive enzyme activities and shrimp growth with their proliferation in shrimp gastrointestinal tract although the shrimp survival was not significantly different. They also significantly reduced the cumulative mortality of shrimp exposed to a virulent AHPND strain (V. parahaemolyticus SR2). This is the first to conclude that selected probiotic PNSB strains have great potential to be used for shrimp cultivation to control vibrios including AHPND strains.

Purple bacteria as added-value protein ingredient in shrimp feed:Litopenaeus vannameigrowth performance, and tolerance againstVibrioand ammonia stress

“…A hypothesis might be that PNSB in the feed were able to colonize the gastrointestinal tract and assist the digestion. Chumpol et al (2017) for example observed that shrimp administered with live PNSB are able to colonize the gastrointestinal tract and assist the digestion by excreting proteases, lipases and amylases. Our study was performed with freeze-dried PNSB.…”

“…sphaeroides have antimicrobial properties (Kaspari & Klemme, 1977). Chumpol et al (2017) have performed a similar screening of PNSB on V. harveyi and V. vulnificus. They isolated 185 PNSB species from shrimp ponds and discovered 10 strains with anti- Vibrio potential belonging to the species Rb.…”

“…Studies have also shown that PNSB have anti- Vibrio properties when administered live (not as feed) to shrimp ponds (Chumpol et al, 2017; Wang & Gu, 2010). In addition, in vitro agar plate experiments revealed that some PNSB strains of Rhodobacter sphaeroides and Afifella marina have anti- Vibrio properties (Chumpol et al, 2017). However, thus far, no studies are available that investigate the anti- Vibrio potential of PNSB contained in feed.…”

Probiotics as a tool for disease mitigation in wildlife: insights from food production and medicine

“…Two common invertebrate pathogens, Vibrio and Aeromonas , have developed resistance to antibiotics; consequently, probiotics are quickly becoming a tool in the aquaculture industry to reduce losses caused by the most common infectious diseases. As a result, research into alternative probiotic treatments has increased, and a number of effective probiotics that inhibit aquaculture pathogens have been identified . Bacterial probiotics treatments, including members of the genera Lactobacillus, Carnobacterium, Bacillus , and Pseudomonas , have been shown to provide protection from disease in turbot, salmon, trout, cod, crab, prawns, oysters, and others …”

“…As a result, research into alternative probiotic treatments has increased, and a number of effective probiotics that inhibit aquaculture pathogens have been identified. 22 Bacterial probiotics treatments, including members of the genera Lactobacillus, Carnobacterium, Bacillus, and Pseudomonas, have been shown to provide protection from disease in turbot, salmon, trout, cod, crab, prawns, oysters, and others. 19,21,23 Although aquaculture currently has one of the most diverse arrays of probiotic organisms that are being used to mitigate pathogens, claims of beneficial probiotic effectiveness are rarely quantified in controlled studies and, surprisingly, "manufacturers of foods and supplements are not required to obtain premarket approval of claims of efficacy or safety."…”