Feed Price and White Feces in Shrimp
By Dr. Wiphada Mitbumrung, Ph.D. Applied Marine Biosciences — Wed Jul 08 2026
Shrimp feed cost is strongly affected by raw material prices. When the price of key feed ingredients increases, feed mills must control formulation cost while still maintaining the declared nutritional value on the feed label. One of the most important nutrients shown on the label is total crude protein. However, total protein alone does not always represent how much protein the shrimp can actually digest and use.
Fishmeal is traditionally a major protein source in shrimp feed because shrimp are carnivorous and require highly digestible animal protein. Fishmeal provides a good amino acid profile, high palatability, and nutrients that are suitable for the short digestive tract of shrimp. Since shrimp have a relatively short gut, they need feed ingredients that can be digested quickly and efficiently.
To reduce feed cost, part of the fishmeal may be replaced with plant-based protein such as soybean meal. Soybean meal can help maintain the total protein percentage in the formula at a lower cost. In laboratory analysis, crude protein is measured by breaking down the feed sample and estimating the nitrogen content. This means the lab can show a high total protein value, even if the shrimp cannot digest and absorb all of that protein efficiently.
In reality, shrimp do not digest feed like a machine in the laboratory. If the protein source is less digestible, a portion of the feed may pass through the gut without being fully digested. Plant-based ingredients can also contain anti-nutritional factors, higher fiber, or less balanced amino acid profiles compared with fishmeal. This can reduce nutrient absorption, increase gut irritation, and increase the amount of undigested material in the intestine.
When undigested feed remains in the shrimp gut or enters the pond environment, bacteria become the main organisms that break it down. This undigested material becomes a good food source for opportunistic bacteria, especially Vibrio spp. If Vibrio levels increase too much, the gut microbiota becomes imbalanced, mucus production increases, and the intestinal lining may be irritated or damaged. This process can contribute to the development of white feces.
Therefore, feed price control must be balanced with digestibility, amino acid quality, ingredient freshness, and gut health. A cheaper feed formula with high total protein may not always give better performance if the shrimp cannot digest and utilize the nutrients. In shrimp farming, the most important question is not only “How much protein is in the feed?” but “How much digestible protein can the shrimp actually use?”