Logo

Bacillus supplementation boost Whiteleg Shrimp performance and resistance to osmotic shock and Vibrio parahaemolyticus

  • By Florian Geay

  • May 28, 2024

The shrimp aquaculture industry faces significant challenges due to suboptimal culture conditions and susceptibility to opportunistic pathogens like Vibrio parahaemolyticus. Given the underdeveloped immune system of shrimp, these factors can lead to high mortality rates and economic losses. Probiotics, particularly strains of Bacillus sp., are increasingly

recognized for their potential to enhance shrimp health and performance. This study, led by Florian Geay, investigates the effects of dietary supplementation with Bacillus pumilus and Bacillus subtilis on the growth, osmotic stress tolerance, and resistance to Vibrio parahaemolyticus in Whiteleg shrimp (Penaeus vannamei).

The feeding trial was conducted using post-larval shrimp (PL12) over a four-week period. Two dietary treatments were tested: a control diet and a diet supplemented with a probiotic mix of Bacillus pumilus and Bacillus subtilis at a concentration of 8.0 x 10^6 cfu/g feed. Each treatment was administered to shrimp housed in eight 400-liter tanks, stocked at a density of 1 PL per liter. Performance metrics such as final mean weight, biomass, average daily gain (ADG), feed conversion ratio (FCR), and survival rate were recorded. 

Osmotic Stress Test 

At the end of the feeding period, 50 shrimp from each tank were subjected to an osmotic shock, transitioning from 8 ppt to 0 ppt salinity. Mortality was recorded

every 30 minutes over a seven-hour period to evaluate osmoregulation capacity. (Figure 1)

Vibrio parahaemolyticus Challenge 

Following the feeding trial, 30 shrimp from each tank were exposed to Vibrio parahaemolyticus in a bath challenge. Mortality was monitored every three hours for three days to assess resistance to bacterial infection. (Figure 2) 

Figure 1: Mortality recorded over the osmotic stress test performed at the end of the feeding trial (N=400)

Results

Growth Performance

Shrimp fed the probiotic-supplemented diet showed significant improvements in growth performance metrics compared to the control group. The final mean weight, biomass, and ADG were all significantly higher in the probiotic group (p<0.05), while FCR was significantly lower, indicating better feed efficiency.

Osmotic Stress Tolerance

Shrimp fed the probiotic diet exhibited enhanced tolerance to osmotic stress, with significantly lower mortality rates compared to the control group

during the osmotic shock test (p<0.01) (Figure 1). This suggests a better capacity of shrimp fed with probiotics to cope with environmental stressors.

Resistance to Vibrio parahaemolyticus

The probiotic-supplemented shrimp also demonstrated increased resistance to Vibrio parahaemolyticus infection. The survival rate was significantly higher in the probiotic group compared to the control group during the bacterial challenge (p<0.01) (Figure 2). The probiotics likely contributed to this improved resistance by competing with the pathogen for nutrients and adhesion sites, and by stimulating the shrimp's immune system.

Figure 1: Mortality recorded over the Vibrio parahaemolyticus challenge performed at the end of the feeding trial (N=240)

The results of this study underscore the potential benefits of probiotic supplementation in shrimp diets. The enhanced growth performance, better feed efficiency, and improved resistance to both osmotic stress and Vibrio parahaemolyticus infection highlight the role of probiotics in promoting shrimp health and robustness. These benefits are attributed to the probiotics' ability to secrete digestive enzymes and essential nutrients, and to modulate the microbial balance in the shrimp gut. 

Dietary supplementation with Bacillus pumilus and Bacillus subtilis significantly improves the growth performance, osmotic stress tolerance, and resistance to Vibrio parahaemolyticus in Whiteleg shrimp. Incorporating probiotics into shrimp feed, alongside optimal farm management and biosecurity protocols, offers a sustainable strategy to enhance shrimp health and mitigate pathogen-related losses. 

Related Insights

Results (6)

    • R&D
    • Nutrition

    Does iron supplementation improve post-smolts Atlantic salmon performance and health in today’s practical diets?

    Iron (Fe) is a crucial trace mineral involved in various biochemical processes in fish. For Atlantic salmon (Salmo salar L.), the dietary iron requirement ranges from 60 to 160 mg/kg. However, these requirements were established using purified diets with highly bioavailable iron forms, and may not reflect the needs in practical diets where interactions with antinutrients such as phytate can affect iron bioavailability.

    Read more
    • R&D
    • RAS

    Effect of different crude protein and lipid levels on growth and feed conversion in Yellowtail Kingfish.

    Yellowtail kingfish (Seriola lalandi) is a highly valued marine species known for its rapid growth and high market price. Predominantly farmed in sea cages in regions such as Australia, New Zealand, Japan, and Mexico, this species is now being explored for recirculating aquaculture systems in Europe and the USA.

    Read more
  • Image of fish being held
    • R&D
    • Nutrition

    Jinni Gu: Natural ingredients support Atlantic Salmon in coping with handling stress

    Atlantic salmon (Salmo salar) farming industry frequently faces the challenge of managing sea lice infestations, which necessitates mechanical treatment procedures that can stress the fish. Handling stress from crowding and delousing can negatively impact fish appetite and growth, leading to economic losses.

    Read more
    • R&D
    • Novel Ingredients

    Navigating the complexity - Challenges and solutions in implementing sustainable raw materials in commercial aquafeeds

    The global aquafeed industry has undergone a significant transformation over the past two decades, shifting from marine-based ingredients to plant-based raw materials. This transition has linked aquafeed production more closely with the environmental and social impacts of agriculture. Sustainable raw material sourcing is critical, given that aquafeed production accounts for up to 80% of the scope 3 greenhouse gas emissions in salmon farming.

    Read more
  • Largemout Bass being held in a pond
    • R&D
    • Nutrition

    Improved heat stress tolerance for Largemouth Bass fed with natural antioxidant

    Largemouth bass (Micropterus salmoides) are a crucial freshwater aquaculture species in China, facing challenges like high water temperatures that cause significant economic losses. One promising solution is using functional feeds with natural antioxidants.

    Read more
    • R&D
    • Nutrition

    A novel krill meal ingredient enhances feed intake following high-temperature lice treatment stress in Atlantic salmon

    Managing sea lice infestations in Atlantic salmon (Salmo salar L.) aquaculture often involves mechanical treatments that can cause acute stress, reducing feed intake and compromising growth.

    Read more

Welcome to BioMar

Choose between the options below

Current selection: Global