Running Mortality Syndrome (RMS) in Intensive Litopenaeus vannamei Culture
Running Mortality Syndrome (RMS) is a chronic, debilitating condition endemic to commercial Litopenaeus vannamei ponds in coastal Andhra Pradesh (West Godavari, Krishna, and Nellore districts). Occurring predominantly between Day of Culture (DOC) 45 and 75, it produces continuous daily mortalities that silently erode 25% to 50% of harvest crop biomass.
Running Mortality Syndrome (RMS) in Litopenaeus vannamei is driven by cumulative feed waste, benthic sediment degradation, sub-lethal un-ionized ammonia ($NH_3 > 0.05\text{ ppm}$), and opportunistic Vibrio campbellii / V. owensii co-infections. Banned antibiotics fail and induce kidney/tubule necrosis. Effective biological remediation requires an immediate 25% feed cut, biological nitrification and sludge degradation: broadcast 2.5 L/acre Next Converter (autotrophic nitrifiers @ 1×10¹⁰ CFU/ml) to clear nitrogenous toxicosis, paired with 5.0 L/acre Next Sludge over central trenches and 20 ml/kg Next Gut probiotic feed coating, arresting daily mortality counts within 72 to 96 hours without chemical shock.
2. Etiology & Polymicrobial Synergy
Comprehensive field investigations by ICAR-CIBA establish that RMS is not induced by a standalone pandemic pathogen, but rather by an environmental-microbial crisis involving three interacting factors:
Between DOC 45 and 75, daily feeding rates reach 35–50 kg/acre. Accumulation of uneaten pellets and pseudofeces collapses bottom sediment redox potential below -180 mV, causing chronic sub-lethal hypoxia ($DO < 2.8\text{ ppm}$).
Elevated Total Ammonia Nitrogen ($TAN > 1.5\text{ ppm}$) and Nitrite ($NO_2^- > 0.4\text{ ppm}$) cause chronic sub-lethal hemocyanin oxidation, severely depressing circulating hemocyte counts and phenoloxidase defense pathways.
Weakened shrimp with depleted cuticular and intestinal mucosal barriers are invaded by opportunistic luminescent and sucrose -ve vibrios (Vibrio campbellii, V. owensii), leading to lymphoid organ spheroids and slow mortality.
3. Gross Field Signs & Behavior
- Persistent Daily Mortalities: 15 to 45 dead shrimp collected every morning in check trays, pump sumps, or along water delivery channels without sudden explosive mass mortality.
- Faded Coloration & Antenna Rot: Affected shrimp exhibit pale bluish or darkened cuticle, broken rostrums, eroded antenna whips, and frayed pleopods.
- Sluggish Benthic Crawling: Moribund shrimp crawl weakly along pond margins or surface aimlessly during hot midday aeration cycles.
- Gut Atrophy & Watery Hepatopancreas: Dissection reveals midguts completely empty or filled with brownish watery fluid; hepatopancreas is shrunken by 30% to 50% with loss of lipid vacuoles.
4. Laboratory Diagnostic Protocol (TCBS & PCR)
| Diagnostic Level | Methodology | Target Observation | Action Threshold |
|---|---|---|---|
| Level 1: Wet Mount Microscopy | Hepatopancreas squash (400x) | Tubule epithelial cell detachment, absence of lipid droplets | > 40% tubule atrophy |
| Level 2: Bacteriological TCBS Plating | Hepatopancreas & hemolymph streak | Mixed green/yellow colonies (V. campbellii, V. parahaemolyticus) | > 10³ CFU/g tissue |
| Level 3: Exclusion PCR | OIE-certified Nested PCR | Screens for WSSV, IHHNV, EHP, and IMNV to rule out viral epidemics | Negative for major OIE viruses |
| Level 4: Nitrogen Water Testing | Nessler / Spectrophotometry | Total Ammonia Nitrogen and Nitrite accumulation | TAN > 1.0 ppm / NO₂⁻ > 0.3 ppm |
Suspect secondary bacterial proliferation? Evaluate colony density with the TCBS Vibrio Colony Biosecurity Risk Matrix.
5. Physical & Feeding Remediation
Immediately cut commercial feed by 25% for 4 days. Overfeeding during an RMS episode accelerates benthic ammonia spikes and feeds opportunistic bottom bacteria.
Maintain continuous aeration (> 5.5 ppm DO at pond bottom) to promote autotrophic nitrification and inhibit anaerobic sulfide-producing bacteria.
If central drain sump exists, flush black sludge sediment for 10 minutes daily during aerator operation to remove decayed organic solids.
6. Biological Therapeutic Regimen (CAA-Approved)
Next Farm Bio Sciences RMS Mitigation Protocol
Manufactured in New Autonagar, Vijayawada. Formulated to neutralize nitrogenous toxicity, digest toxic sludge trenches, and restore gut mucosal barrier function:
Broadcast Next Converter at 2.5 Litres per acre during morning hours with active aeration. High-potency autotrophic Nitrosomonas europaea and Nitrobacter winogradskyi (1×10¹⁰ CFU/ml) permanently oxidize ammonia and nitrite within 48 hours, eliminating branchial hypoxia.
Broadcast Next Sludge at 5.0 Litres per acre directly over feeding paths and central sludge zones. Enzymatic consortia digest uneaten feed proteins and suppress anaerobic Desulfovibrio bacteria.
Top-dress feed with Next Gut (20 ml/kg) containing Bacillus subtilis and prebiotic mannans. Re-establishes healthy gut microflora, repairs damaged hepatopancreatic B-cells, and halts secondary internal bacteremia.
7. Economic Impact Analysis & FCR Trajectory
| Economic Parameter | Untreated / Antibiotic Flare-Up | Next Farm Biological Protocol | Net Farm Margin Impact |
|---|---|---|---|
| Daily Check Tray Mortality | 25 – 50 shrimp / tray / day | < 2 shrimp / tray / day | Halts continuous biomass drain |
| Average Harvest FCR | 1.85 – 2.10 | 1.35 – 1.42 | Saves ₹38–₹52/kg in feed costs |
| Final Crop Survival Rate | 54.0% – 62.0% | 88.5% | +31.5% harvest biomass delivered |
| Harvest Count Uniformity | Severe size variation (> 25% CV) | Uniform 30 count grading | Premium export price realization |
8. Frequently Asked Questions (Clinical Q&A)
What is Running Mortality Syndrome in vannamei shrimp?
Running Mortality Syndrome is a chronic attrition condition occurring between DOC 45 and 75 where ponds suffer low but persistent daily mortalities of 15 to 50 shrimp per check tray, silently eroding up to 50% of harvest crop biomass.
How do you stop daily running mortality in shrimp ponds?
Running mortality is stopped by immediately reducing feed by 25%, broadcasting 2.5 Litres per acre of autotrophic Nitrosomonas consortia like Next Converter to eliminate un-ionized ammonia, and applying 5.0 Litres per acre of Next Sludge to digest accumulated feeding trench wastes.
Why do antibiotics fail against Running Mortality Syndrome?
Antibiotics fail against RMS because it is an environmental-microbial crisis driven by benthic organic sludge and sub-lethal ammonia rather than a single bacterial infection, and administering antibiotics destroys the shrimp hepatopancreas and induces acute kidney damage.
Clinical References & Authoritative Sources:
- ICAR-Central Institute of Brackishwater Aquaculture: Running Mortality Syndrome Etiology & Mitigation in Brackishwater Aquaculture.
- National Fisheries Development Board (NFDB): National Aquaculture Standards & Biosecurity Framework.
- Coastal Aquaculture Authority: Approved Antibiotic-Free Veterinary Inputs.
- Marine Products Export Development Authority: Guidelines for Antimicrobial Residue Elimination in Export Shrimp.
- Food and Agriculture Organization (FAO): Biosecurity and Disease Management in Asian Penaeid Aquaculture.
Prescribed Commercial Medicine: Next Viro Nill
రొయ్యల వ్యాధి నివారణకు సిఫార్సు చేయబడిన మందు: Next Viro Nill
Clinical Formulation
Broad Spectrum Clinical Biosecurity Consortium
1 Litre per acre for 3 alternate days
Manufacturer & Compliance
Next Farm Bio Sciences Private Limited (Vijayawada)
100% Antibiotic-Free Formulation — Formulated in compliance with CAA & MPEDA export standards (Zero Chloramphenicol & Nitrofurans Guarantee)
Frequently Asked Questions & Treatment Guide / తరచుగా అడిగే ప్రశ్నలు
How to stop running mortality syndrome (RMS) in shrimp farming?
చెరువులో రోజువారీ రొయ్యల చావులను (RMS) ఎలా ఆపాలి?
Stop excessive feeding, flush organic load, and apply Next Viro Nill at 1L/acre to eliminate lethal pathogenic viral-bacterial complexes.
మేత తగ్గించి, Next Viro Nill ప్రోబయోటిక్ వేయడం ద్వారా రన్నింగ్ మోర్టాలిటీని పూర్తిగా అరికట్టవచ్చు.