Why Bacteriophages?

With emergence of highly virulent pathogens in animal health and aquaculture, there is need for highly effective therapeutic product which can reduce usage of sanitisers and antimicrobials. Continuous use of sanitisers and antimicrobials lead to damage of microbiome (the normal non-pathogenic beneficial bacteria) in aquaculture pond ecosystem and shrimp gut. Recent explosion of scientific research has brought to light the importance of maintaining good and unfluctuating microbiome in shrimp and fish health and aquaculture success.

Under this condition Bacteriophages against virulent pathogens in aquaculture will be highly helpful in maintaining the natural ecosystem of the pond while killing the aquaculture pathogens. This strong argument inspired Salem Microbes to initiate Bacteriophage research as early as 2018 and has invested in infrastructure, technology, and technical competence in bacteriophages-based solution development for Aquaculture, Poultry and Food safety.

Salem Microbes possessing 23 years of probiotic tradition has always travelled with Bacteriophages hand in hand from screening to production operations. In the current day scenario, we are ‘embracing the foe as a friend’ to control pathogens of aquaculture. So, we are just jumping sides and exploiting their potential.

Today, we assure that we are in the forefront of bacteriophage research, specialising in isolation, characterisation, and formulation of Phage cocktail within a short turnaround time. Our Research & Development ensures quick screening in case of a sudden disease outbreak to make custom formulation of Bacteriophages from our expansive library of Bacteriophages maintained on-campus.

Phages and Probiotics , a Synergistic combination

Probiotics have played an undeniable role in the environmental management of the shrimp pond and are going to continue to sustain the shrimp ecosystem microbiome, the only catch here is use of quality probiotic inputs which farm owners and technical experts should be aware of.

Probiotics reduce the chances of infection by Competitive Exclusion, but once the critical levels of Vibrio species dominate the environment, it become nearly impossible for probiotic bacteria to exclude Vibrio species. Such critical condition demands quick and sure shot treatment, which is non residual in nature and non-GMO and which does not affect the (microbiome). Here comes the concept of Phage Therapy which is highly specific and quick acting in nature specifically targeting the aquaculture pathogens.

How a Bacteriophage product become relevant to a condition?

A Good Bacteriophage consortia should contains identified lytic phages, specific against pathogens selected from the target environment. Phage cocktails against Pathogens should be continuously upgraded to maintain the pathogen spectrum, specificity and infectivity.

How does a Phage works?

Bacteriophages are Viruses of bacteria which enter the bacteria, use the bacterial source of energy, hijack the bacteria, multiply inside the bacteria and kill them by lysis. When they kill the bacteria, each virus which enter the bacteria multiplies and releases 10 to 100 mature ready-to-attack bacteriophages which are capable of infecting and destroying next set of target pathogenic bacteria.

V PHAGES Consortia

V PHAGES Cocktails for Hatchery and Growout are quite different in their Formulation, Specificity and Purpose. V PHAGES HATCHERY satisfy the need for targeting pathogens specific and prevalent in Hatchery water source, live feeds and also its environment. V PHAGES GROWOUT targets the common pathogens esp Vibrios which are the main cause for bringing down the productivity of a shrimp pond by causing Vibriosis leading to White gut, White faecal disease, off feed, Running Mortality Syndrome and crop loss.

"V PHAGES " cocktails target Vibrio species as,

• Vibrio parahaemolyticus
• Vibrio alginolyticus
• Vibrio harveyi
• Vibrio campbellii and other pathogenic Vibrio sp.

When TO USE IN SHRIMP HATCHERIES?

• To reduce the load Vibrio sp. of the live/ wet/ frozen feed used in brood stocks.
• To reduce Vibrio sp. load in artemia tank.
• To reduce the Vibrio sp. associated problems in Conversion and PL tanks.
• To reduce Vibrio sp. load in intake water thereby preventing biofilm formation in the storage tanks and pipe line downstream of the intake tank.

When TO USE IN SHRIMP GROWOUT PONDS

• Drop in feed intake with increase in yellow or green colonies in TCBS plates
• White gut and White faecal matter appearance coupled with more green colonies in TCBS plates
• Early stages of Running mortality syndrome with empty gut symptom.
• During stocking to safeguard against survival loss of PL’s.
• To increase the efficacy of Probiotics by reducing their primary enemies, the pathogenic

Comparing with Other Therapies

V PHAGES are Natural isolates screened and selected for their strong and fast action against their challenged targets. They do not disturb the Probiotics and other non-pathogenic natural microbiome which are otherwise destroyed by other treatment approaches as Sanitisers, Disinfectants and any products of anti-microbial action. These Phages does not leave any residues on the shrimp or environment as they are Natural. All  bacteriophages in V PHAGES cocktail are Genotypically characterized to ensure proprietary formulation and traceability, which makes them special.

Conclusion

Though Bacteriophage research and applications are known for many years very few products have seen the light of the day. Even these products become irrelevant when they are not supported by a strong expertise in the field and research infrastructure. Salem Microbes has established these capabilities and commits to be in the forefront of giving the Best to its farmers to make their Shrimps Healthy, Productive and Profitable.

Bacterial infections of farmed shrimp are quite common and likely the major cause of mortality in farmed shrimp. Vibriosis is one of the most severe bacterial diseases in shrimp farming caused by Vibrio spp. These bacteria from part of the natural microbiota of wild and cultured shrimp and the marine environments.  Vibrio infections have become a major constraint of the production and trade in shrimp aquaculture. They are responsible for several diseases and mortalities of up to 100% and cause crop loses globally.

Vibrio usually associated with multiple etiological agents. Vibrio has been reported in penaeid shrimp culture systems implicating at least 14 species and they are Vibrio harveyi, V. splendidus, V. parahaemolyticus,V. alginolyticus, V. anguillarum, V. vulnificus, V. campbelli, V. fischeri, V.damsella, V. pelagicus, V. orientalis, V. ordalii, V. mediterrani, V. logei etc. However some Vibrio species have been identified as primary pathogen,  including V. parahaemolyticus and V. harveyi have been described as the main pathogenic species in shrimp. 

Clinical signs of Vibriosis

• • Redness of body
  • Antennae cut
  • Atrophy of hepatopancreas
  • White faeces
  • Delayed hemolymph
  • Luminescence in dark
  • Anorexia
  • Lethargy
  • Melanization
  • White patches in the abdominal muscle
  • Expanded chromatophores
  • Luminescence and necrotic areas in the uropods
  • Mortality

Shrimp diseases associated with Vibriosis

Vibrio can remain in the environment without causing disease, but can very easily switch from opportunistic and commensal to pathogenic when conditions change. Thus, its ability to cause disease or increase in virulence, is a complex process affected by many variables, including host, vibrio species, developmental stage, physiological conditions, environmental stress, and infection method.

They are several diseases associated with Vibriosis.

• • V.harveyi - Luminous disease
  • V.Parahaemolyticus – EMS/AHPND
  • Vibro sp. - White Faecal Disease (WFD)

Diagnosis

Diagnosis of vibrio infection is based on clinical signs and the histological demonstration of rod-shaped Vibrio bacteria in lesions, nodules or haemolymph. Excised organs and haemolymph may be streaked on a Vibrio-selective (TCBS) or general marine agar plate. Vibrio isolates may be identified by a number of methods, including: Gram stain, motility, an oxidase test, mode of glucose utilisation, growth in the presence of NaCl, nitrate reduction and luminescence.  

Vibrio threshold in shrimp farms:

There are many  vibrios maximum threshold standards in farms. Most of them are for Vibrio spp. in pond water. These are the common maximum thresholds used by shrimp farms:

• Total Vibrio Count (TVC): varies from 10³CFU/mL to 10⁴ CFU/mL. Some farmers adopt the TVC of 10² CFU/mL as the maximum threshold. Total Vibrio Count (TVC) in shrimp gut is 10⁵ CFU/g
• Vibrio colonies:10² CFU/mL for green colonies and 10³ CFU/mL for yellow colonies.
• Vibrio percentage: 5% to 10% TVC of total plate count, and 10% Vibrio green colonies of TVC.

How to prevent Vibrio problems?

Vibrios are difficult to eradicate because they adopt well to different environment conditions and can adopt state when facing adverse conditions. However, Vibriosis is controlled by rigorous water management and sanitation to prevent the entry of vibrios in the culture water and to reduce stress on the shrimps. Pond Management and robust gut health are important strategies to control vibrio, together with frequent sampling to monitor their levels in the shrimp gut and pond ecosystem.

Good site selection, pond design and pond preparation are also important. Maintain adequate water quality with low bacterial biomass, A stable phytoplankton bloom and a proper feeding program, Sterilize or filter recirculated water, Routinely monitor shrimp and pond for early diagnosis of a problem, Avoid temperature extremes or rapid variation in temperature, handling, overcrowding, and other stressors, Infections opportunistic and probably result from poor husbandry; may be secondary to other disease processes. An increase in daily water exchanges and a reduction in pond biomass by partial harvesting are recommended to reduce mortalities caused by vibriosis.

The combination of gut acidifiers, prebiotics, use of natural antimicrobials and Probiotics, Bacteriophage applications, immunostimulants and non-antibiotic substances has superior specificity against vibriosis and Luminescent Bacteria (LB) coupled with Best Aquaculture Practices (BAP) , which makes it an effective management tool for the control of vibriosis and bacterial toxicity in aquaculture.

Treatment

Use V Phages Growout immediately when various symptoms of Vibriosis as Luminescence in water, infections in shrimp and or low feed intake etc., correlated by lab test.