Effect of Moisture Content, Processing Water Temperature, and Immersion Time on Water Stability of Pelleted Shrimp Diets

An experimental shrimp diet was processed at four moisture levels (34%, 37%, 40%, and 43%) and two water temperatures (26°C and 100°C) and formed into feed pellets by means of a meat grinder. Eight pellet samples were immersed in a seawater aquarium for 1, 2, and 4 hours to test the water stability index (WSI) of these pellets in a 2 3 3 3 4 factorial design. Results showed that mean WSI of pellets ranged from 73.8% to 94.5%. Pellets processed at 40% moisture with 100°C water, immersed in water for 1 hour, had the highest WSI. Pellets processed with 100°C water had significantly higher WSI than those processed with 26°C water (P< 0.05). Pellets processed at 34% moisture content had significantly lower WSI than those processed at 37%, 40%, and 43% moisture contents (P< 0.05). Pellets processed at 37% moisture level had a significantly lower WSI than those processed at 40% moisture level (P< 0.05) but were not significantly different than those processed at 43% moisture level (P> 0.05). Pellets immersed in water for 1 hour had a significantly higher WSI than those immersed in water for 2 hours and 4 hours (P< 0.05). Likewise, pellets immersed in water for 2 hours had a significantly higher WSI than those immersed in water for 4 hours (P< 0.05). Therefore, shrimp diets made with a meat grinder should be processed at 40% moisture with 100°C water.