Starving Shrimp for 1 day to get better result

By Dr. Wiphada Mitbumrung, Ph.D. Applied Marine Biosciences — Wed Mar 04 2026

Feed contributes nearly 50% of total shrimp production cost, making it the single largest operational expense in most commercial farms. Because of this economic pressure, farmers constantly search for strategies to reduce feed cost without compromising performance. Some reduce formulation cost by incorporating lower quality ingredients, including higher inclusion of plant proteins to partially replace fishmeal. Others experiment with feeding management strategies such as intermittent fasting or cyclical feed restriction to improve feed efficiency. While these approaches may offer short term financial appeal, scientific evidence shows that both strategies carry biological consequences that must be carefully evaluated.

One major consequence is water quality, because in shrimp ponds feed is not only a growth input, it is also the main waste input. Every kilogram of feed delivered to the pond becomes either shrimp biomass or organic loading through uneaten pellets, feces, and dissolved metabolites. Uneaten feed is commonly linked to feeding that does not match shrimp age and pellet size, overfeeding caused by imprecise feeding rate calculations, or reduced feed attraction when low palatability ingredients are used, which can occur in some high plant protein formulations. Uneaten feed also increases during incidents that reduce shrimp appetite, such as stress from heavy rain and rapid salinity change, disease pressure, low dissolved oxygen, or other abrupt shifts in pond conditions. When feed waste increases, organic matter accumulates in the water column and bottom, driving microbial oxygen demand, increasing unstable metabolites, and pushing pond conditions toward lower oxidation reduction potential and higher risk of water quality crashes. In contrast, when waste input is reduced, the organic load declines and the system becomes easier to stabilize. This is also where pond probiotics play a role. By accelerating biodegradation of organic waste and improving the balance between decomposition and oxygen availability, probiotics help manage the gap between organic input and system capacity, supporting a more stable oxidation reduction potential and reducing the chance that accumulated organic matter will overwhelm pond biology.

The second consequence is the direct effect on shrimp performance and survival. Study from Shao et al. evaluated cyclical fasting under intensive culture conditions for six weeks, shrimp were divided into a continuously fed control group and two fasting treatments, F1 with one fasting day per week and F2 with two fasting days per week. Growth parameters such as final weight, weight gain, and specific growth rate were not significantly reduced in fasting groups. In fact, the F1 group showed slightly higher final weight at 15.45 g compared with 14.81 g in the control, and weight gain reached 136.91% compared with 127.21%in the control. Specific growth rate was also slightly higher in F1 at 2.05% per day compared with 1.95% per day in the control. Feed efficiency increased markedly in fasting treatments, from 0.67 in the control group to 0.84 in F1 and 0.75 in F2, indicating more efficient nutrient utilization during refeeding. However, survival rate told a different story. The survival rate of F1 and F2 dropped significantly. This substantial decline in survival offset the apparent improvement in feed efficiency. Although shrimp that survived fasting converted feed more efficiently, the total harvestable biomass was reduced because fewer shrimp reached market size.

Conclusion:

Any feeding strategy should be judged not only by growth and feed efficiency, but also by its impact on pond stability, because feed is the main driver of organic loading in shrimp ponds. Water quality can improve when unnecessary feed input is reduced, but this should be achieved through accurate feeding and better feed management, not through harsh restriction that compromises shrimp survival. At the same time, harsh fasting can increase stress and mortality.

Reference:

Shao, J.-C., Zhu, W.-Q., Liu, M., Wang, L., & Zhao, W. (2020). Cyclical fasting and refeeding is not an advisable feeding strategy for white shrimp (Penaeus vannamei). Aquaculture Reports, 18, 100429.