IMPACT OF TEMPERATURE ON THE GROWTH AND DEVELOPMENT OF WHITELEG SHRIMP (Litopenaeus vannamei) – PRACTICAL APPLICATIONS IN FEED MANAGEMENT
IMPACT OF TEMPERATURE ON THE GROWTH AND DEVELOPMENT OF WHITELEG SHRIMP (Litopenaeus vannamei) – PRACTICAL APPLICATIONS IN FEED MANAGEMENT
Shrimp are ectothermic animals, meaning their body temperature depends entirely on the surrounding water temperature. Therefore, throughout their growth and development, any fluctuation in temperature directly affects metabolic rate, digestive capacity, and feeding behavior.
Water temperature is the most influential ecological factor governing metabolic activity in whiteleg shrimp. When temperature changes, metabolic rate, digestive enzyme activity, and nutrient absorption efficiency also change accordingly. This results in clear variations in feeding intensity at different times of the day. Under high-density farming conditions in lined ponds, shrimp become even more sensitive to temperature fluctuations, increasing production risks if feed management is not adjusted appropriately.
1. Effect of Temperature on Feed Utilization Efficiency
As temperature increases, the shrimp’s metabolic rate rises. To meet higher energy demands, shrimp must increase respiration to obtain sufficient dissolved oxygen (DO). At the same time, feed intake increases and digestion occurs faster than under normal conditions. However, the amount of endogenous digestive enzymes in shrimp is limited; therefore, although shrimp eat more, nutrient absorption does not increase proportionally. This leads to higher feed consumption without corresponding weight gain, resulting in increased FCR.
Moreover, under high-temperature conditions, metabolic waste from digestion decomposes rapidly at the pond bottom. This decomposition consumes oxygen, causing localized hypoxia and creating favorable conditions for the formation of toxic gases such as H₂S and NH₃. These factors induce stress, damage gills and hepatopancreas, and promote the growth of pathogenic bacteria.
Conversely, when temperature drops sharply (due to monsoons, heavy rain, or sudden weather changes), shrimp metabolism decreases significantly, leading to reduced feeding, prolonged digestion, and delayed molting. In nursery or post-larvae stages, shrimp have a very low tolerance to cold; when temperature falls below the minimum threshold, shrimp may stop feeding and suffer mass mortality. Shrimp tend to move to the pond bottom to avoid cold water, but this zone often contains high levels of toxic gases and fungi, increasing disease risk.
2. Temperature Thresholds and Feeding Responses of Whiteleg Shrimp
2.1. Low Temperature (< 26°C): Markedly Reduced Feeding
Below 26°C, shrimp metabolic rate decreases sharply, digestive enzyme activity slows, and intestinal peristalsis weakens. Shrimp swim slowly, spend more time at the bottom, feed poorly, and require longer digestion time. High feeding levels during this period easily result in feed waste, bottom pollution, and rapid phytoplankton decline.
Practical application:
Reduce feed by 20–30%.
Focus feeding during sunny periods when temperature rises.
Supplement digestive enzymes or gut probiotics in the morning.
2.2. Optimal Temperature (28–30°C): Strong Feeding and Best Growth
At 28–30°C, metabolic rate and nutrient absorption reach optimal levels. Shrimp are active, intestinal motility increases, and the enzyme system remains stable. This is the period with the best FCR and fastest weight gain.
Practical application:
Feed up to the shrimp’s actual appetite.
Increase feeding in the morning and early afternoon; limit increases in late afternoon or evening.
Maintain DO > 5 mg/L to optimize digestion.
2.3. High Temperature (31–32°C): Gradual Reduction in Feeding
Above 31°C, shrimp expend more energy to maintain osmotic balance and cope with heat stress. DO declines rapidly in warm water, forcing shrimp to prioritize respiration over digestion, resulting in reduced feeding. Intestinal digestion slows, and soft feces become more common.
Practical application:
Reduce feed by 10–20% during midday and afternoon meals.
Increase aeration during the hottest hours.
Apply mineral supplements to stabilize osmotic pressure.
2.4. Very High Temperature (> 33°C): Feed Refusal and Heat Shock Risk
Beyond 33°C, shrimp activity decreases sharply and feeding almost stops. The hepatopancreas becomes vulnerable, and Vibrio bacteria proliferate rapidly at high temperatures. Uneaten feed during this period easily triggers NH₃ and NO₂ toxicity, leading to white feces syndrome and bacterial outbreaks.
Practical application:
Completely stop midday feeding if temperature exceeds 33°C.
Avoid sudden water exchange to prevent heat shock.
Apply minerals and probiotics at appropriate times to reduce environmental stress.
2.5. Large Day–Night Temperature Fluctuation (> 5°C): Abnormal Feeding Reduction
Large temperature differences between day and night easily cause stress, especially during the 25–40 day growth stage. When temperature drops significantly at night and rises rapidly at midday, digestive enzymes become “disrupted,” leading to reduced feeding even when other water parameters appear normal.
Practical application:
Do not increase feed on days with large temperature fluctuations.
Increase oxygen supply from 1:00–3:00 a.m.
Enhance water circulation and bottom aeration to prevent thermal stratification.
3. Adjusting Feed Based on the Day–Night Temperature Curve
Practical experience shows that shrimp feed most actively when temperature remains stable between 27–30°C for 6–8 consecutive hours. In contrast, if temperature rises rapidly from 27°C to 33°C within 2–3 hours, shrimp will reduce feeding during midday meals, even though they are still at a strong feeding age.
Key management points:
Gradually increase feed in the morning as temperature rises.
Reduce or stop feeding when temperature reaches its peak.
Slightly increase feed again in the early evening when temperature drops to 28–30°C.
In the late evening, maintain only enough feed to stabilize gut function.
4. Role of Dissolved Oxygen (DO) Under High Temperature Conditions
Higher temperature → lower DO → reduced digestive activity.
In high-density ponds (120–300 shrimp/m²), when DO falls below 4.5 mg/L, shrimp will automatically reduce feeding, even if temperature remains within the optimal range.
Practical application:
Operate 100% of paddlewheel aerators from 11:00–16:00.
Increase bottom aeration in areas with high shrimp concentration.
Reduce feed when DO < 5 mg/L.
5. Temperature-Based Feeding Protocol (Practical Application)
Based on data collected from multiple farming regions, the recommended temperature-based feeding protocol is as follows:.
| Temperature | Feeding Level | Technical Notes |
|---|---|---|
| < 26°C | Reduce 20–30% | Feed when temperature rises |
| 28–30°C | Maximum feeding | Optimal growth period |
| 31–32°C | Reduce 10–20% | Increase aeration, reduce midday meals |
| > 33°C | Stop midday feeding | High risk of heat shock |
| Day–night fluctuation > 5°C | Do not increase ration | High risk of digestive disorders |
Conclusion
Temperature is a decisive factor directly influencing feeding behavior and growth rate of whiteleg shrimp. Understanding temperature thresholds and digestive responses, combined with time-specific feed adjustments, helps reduce feed waste, limit water pollution, and protect shrimp gut health. In high-density lined ponds, temperature-based feed management is not only a necessary technique but also a core solution for achieving high economic efficiency and minimizing risks under increasingly unstable weather conditions.
