How do I treat White Gut Syndrome in shrimp without using antibiotics?

Apply Next Gut multi-strain probiotic (Citrobacter, Lactobacillus, Saccharomyces) mixed with feed at 15-20ml per kg twice daily for 5 days. Simultaneously broadcast Next Viro Nill water bio-conditioner at 1 Liter per acre to eliminate pathogenic Vibrio reservoirs.

What is the dosage of Next Converter for severe ammonia (NH3) spikes in pond water?

For active toxic ammonia spikes above 0.5 ppm TAN, apply 2.0 to 3.0 Liters of Next Converter per 1 Acre of pond surface (1 meter water depth) during morning aeration.

Are Next Farm Bio Sciences products approved by the Coastal Aquaculture Authority (CAA)?

Yes. All biological formulations produced by Next Farm Bio Sciences are approved by the Coastal Aquaculture Authority (CAA), certified under ISO 9001:2015, and guaranteed 100% free from banned antibiotics.

Can I order Next Farm products using Cash on Delivery (COD)?

No. To ensure optimal biological cold-chain handling and prevent transit delays for living bacterial formulations, all orders must be pre-paid securely online via Razorpay (UPI, GPay, PhonePe, Cards, NetBanking).

How quickly are orders dispatched to prawn farms in Andhra Pradesh?

Pre-paid orders confirmed before 2:00 PM IST are dispatched same-day from our New Autonagar, Vijayawada warehouse via dedicated express aquaculture freight, reaching coastal districts within 24-48 hours.

Microsporidian PathologyCHRONIC MORBIDITY & STUNTINGHost: Litopenaeus vannamei, Penaeus monodon

Enterocytozoon hepatopenaei (EHP) Microsporidian Stunting

Scientific Classification: Enterocytozoon hepatopenaei (Phylum Microsporidia)

తెలుగు ప్రాంతీయ వ్యాధి సమాచారం (Andhra Pradesh Regional Advisory):

రొయ్యల ఎదుగుదల లోపం (EHP) మైక్రోస్పోరిడియా నివారణ

వనామి రొయ్యల్లో సైజు వైవిధ్యం, ఎదుగుదల లోపం కలిగించే EHP మైక్రోస్పోరిడియా గుర్తింపు మరియు నేల, నీటి యాజమాన్య పద్ధతులు.

Jump to:Overview Etiology Gross Signs Microscopy & PCR Differential Matrix CAA Protocol FAQs

1. Clinical Overview

Enterocytozoon hepatopenaei (EHP) is an intracellular microsporidian parasite that replicates exclusively within the tubule epithelial cells of the penaeid shrimp hepatopancreas. Unlike acute viral pathogens that cause rapid catastrophic mortality, EHP causes severe nutrient absorption failure, leading to profound growth stunting, size disparity (coefficient of variation > 35%), elevated FCR (> 1.8), and extreme vulnerability to secondary White Feces Syndrome and bacterial vibriosis.

2. Etiology & Transmission Dynamics

Causative Agent

Enterocytozoon hepatopenaei, an obligate intracellular microsporidian featuring an extrusion polar filament mechanism for host cell injection.

Transmission Mode

Oral ingestion of infectious spores from live feed (polychaetes, artemia), infected hatchery post-larvae (PL), and cannibalism of infected molts/carcasses.

Incubation Period

Sub-clinical replication over 15 to 30 days; visible growth cessation typically evident after DOC 35.

Expected Mortality

Low direct mortality (< 5%), but economic mortality reaches 80% due to unmarketable stunted shrimp and excessive feed costs.

Primary Target Organ: Tubule epithelial cells (B, F, and R cells) of the digestive hepatopancreas gland.

3. Gross Pathology & Field Signs

A. Pond Dike & Aerator Observations

Growth stagnation: shrimp remain 8–12 grams at DOC 70–80 when standard growth curve expects 18–22 grams.
Extremely wide size distribution in cast nets ranging from 6g pin-heads to 16g normal shrimp.
Soft shells and lethargic feeding response during routine feeding tray checks.

B. Check Tray Pathology

Check trays indicate normal or slightly reduced feed consumption, yet biomass growth fails to correlate with feed fed.
Occasional white fecal strings floating or adhering to trays indicating active ATM transformation.
High percentage of shrimp exhibiting empty digestive tracts despite feed presence.

C. Gross Dissection Findings

Hepatopancreas appears pale, reduced in volume, and exhibits loss of dark brown lipid pigmentation.
Fragile gut wall that tears easily during longitudinal dissection.
Absence of normal food bolus in the midgut and hindgut.

4. Microscopic & Molecular Laboratory Diagnosis

Wet Mount Microscopy

Squash mount of hepatopancreatic tissue at 1000x oil immersion reveals clusters of highly refractile, oval spores measuring 1.1 µm by 0.6 µm.

Histopathology (H&E)

Multinucleate plasmodia and dense clusters of mature spores within hypertrophied cytoplasm of sloughing tubule epithelial cells.

Special Stains

Gram-chromotrope or Uvitex 2B fluorescent staining highlights the chitinous spore wall with bright fluorescence under UV microscopy.

PCR Assay Primers

Nested PCR targeting Spore Wall Protein (SWP1): External primers SWP1F/R (514 bp) and Internal primers SWP1nF/nR (148 bp) providing definitive non-cross-reactive detection.

5. Water Quality Trigger Thresholds

Parameter	Critical Danger Threshold	Biological Impact on Shrimp
Organic Matter (BOD / COD)	Excessive sludge accumulation > 5 cm	Serves as environmental benthic reservoir shielding EHP spores from solar UV breakdown.
Alkalinity	< 100 mg/L as CaCO3	Exacerbates osmotic stress, reducing epithelial regeneration capacity.
Salinity Fluctuation	Sudden swing > 5 ppt in 24 hours	Triggers mass polar filament extrusion and widespread host cell invasion.

6. Differential Diagnosis (Rule-Out Matrix)

Versus: Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV)

Key Distinguishing Features: IHHNV produces "Runt-Deformity Syndrome" (RDS) characterized by bent rostra, deformed antennae, and cuticular blisters. EHP causes size variation without morphological cuticular deformities.

Definitive Diagnostic Test: IHHNV 309 bp PCR vs EHP SWP1 PCR.

Versus: Poor Feed Quality / Nutritional Deficiency

Key Distinguishing Features: Nutritional deficiency affects the entire pond uniformly without high size disparity. EHP produces dramatic size disparity (bimodal distribution).

Definitive Diagnostic Test: Microscopic identification of refractile spores in HP tissue.

7. CAA Statutory Biological Protocol

100% Antibiotic-Free

Spore Wall Digestion & Benthic Bioremediation

Feed Application

Maintain standard feeding ration.

Water Application

Broadcast Next Sludge @ 1 Kg/Acre combined with 20 Kg toasted jaggery fermented for 12 hours across aerator currents.

Timing & Rationale: (Day 1 at 08:00 AM) High-enzyme Bacillus consortia (chitinase, protease, cellulase) break down the extracellular chitin matrix of environmental spores and decompose organic sludge.

Intestinal Microbial Competition with Next Gut

Feed Application

Administer Next Gut @ 15 ml/kg of feed across all 4 daily meals.

Water Application

None.

Timing & Rationale: (Continuous from Day 1 to Day 10) Lactic acid bacteria produce organic acids lowering intestinal pH to < 5.8, inhibiting EHP spore germination and polar tube extrusion.

Nutrient Bioavailability Enhancement with Next Food Pro

Feed Application

Combine Next Food Pro @ 10 g/kg feed during the 2nd and 4th meals to restore protease and amylase activity.

Water Application

None.

Timing & Rationale: (Day 5 through Day 20) Supplies exogenous digestive enzymes and essential amino acid chelates to bypass atrophied hepatopancreatic enzyme secretion, restarting muscle accretion.

8. Clinical Frequently Asked Questions

Q: Can EHP be cured 100% once shrimp are infected?

Because EHP is an intracellular parasite, fully infected cells cannot reverse infection. However, our biological protocol halts secondary spore replication, protects uninfected epithelial cells via competitive exclusion, digests environmental spores in sediment, and restores feeding efficiency.

Q: What is the recommended pond preparation protocol to kill EHP spores before stocking?

After pond draining, apply Agricultural Quicklime (CaO) @ 2,000–3,000 kg/acre on moist soil. Ensure soil pH reaches > 12.0 for at least 5 consecutive days. This hydrolyzes the chitin spore wall and kills latent spores completely.

Scientific Citations & Institutional References

Tangprasittipap, A. et al. (2013). The microsporidian Enterocytozoon hepatopenaei is not the cause of white feces syndrome in whiteleg shrimp Penaeus (Litopenaeus) vannamei. BMC Veterinary Research, 9, 139.
Tourtip, S. et al. (2009). Enterocytozoon hepatopenaei sp. nov. (Microsporida: Enterocytozoonidae), a parasite of the black tiger shrimp Penaeus monodon (Decapoda: Penaeidae). Journal of Invertebrate Pathology, 102, 105–112.
Jaroenlak, P. et al. (2016). Improved PCR primers for detection of the microsporidian Enterocytozoon hepatopenaei (EHP) using ‘SWP’ spore wall protein gene. Aquaculture, 453, 52–56.