محمود نفیسی بهابادی

Feed costs can account for as much as 40 to 60% of production costs. It is critical to minimize the cost of feeds relative to production output. For reducing feed costs, it is necessary to use alternative protein sources, such as soybean meal, for fish meal. Shrimp diets which are used as pellets should have minimum disintegration in water. The main objective of this research was to study the stability of diets formulated to contain 42% soybean meal in saline sea water. The stability of diets formulated using binders: three natural substances (gelatin, wheat starch and corn starch), one modified substance (Carboxymethyl cellulose; CMC) and one artificial substance (Urea formaldehyde; UFA) together with a pellet without any binder (control) was evaluated in saline sea water for 240 min. Results showed that leaching in sea water for pellets formulated using UFA and three natural binders were the lowest and highest, respectively. Changes in pellet stability in water with time for both CMC and UFA were similar. Changes in stability in water with time for pellets formulated using wheat starch and corn starch were similar to gelatin. During the experimental period (240 min), the percent weight reduction for the control was 16.7%, for pellets formulated using modified or artificial substance was 8.6%; whereas the weight reduction for pellets formulated using natural substances (gelatin, wheat starch and corn starch) was 13.4%. Due to suitable price and availability, the corn starch is an effective binder for formulating shrimp feeds (pellets) containing 42% soybean meal.