Testing feeds and feed ingredients for juvenile pink shrimp Farfantepenaeus paulensis: in vitro determination of protein digestibility and proteinase inhibition

Protein is the major component for shrimp feeds and must be nutritionally appropriate and readily digestible. In vitro protein digestibility of feeds and feed ingredients, and their inhibitory effect on the digestive proteases of juvenile Farfantepenaeus paulensis were examined. The analysis included animal (four types of fish meal, meat meal and blood meal) and plant (soybean meal and wheat flour) ingredients. Commercial shrimp feed from different sources were also assessed. The degree of hydrolysis of feedstuff with shrimp enzymes was determined through the pH-stat routine as well as monitored in SDS-PAGE over time. Enzyme inhibition of shrimp enzymes was verified by spectrophotometric and substrate-SDS-PAGE assays. Brazilian fish meal, meat meal and wheat flour presented higher digestibility either by in vitro degree of hydrolysis as in SDS-PAGE. Intermediate digestibilitywas found forSuper PrimeChilean andArgentinean fishmeals. Least digestible ingredients were soybean meal and blood meal that exhibited high inhibitory effects on shrimp proteinases. Commercial shrimp feeds also differed in terms of digestibility and inhibitory effects. The routine may be employed for quality control of feedstuffs for shrimp culture, being potentially applicable to different segments of the shrimp culture industry such as feed suppliers, feed manufacturers and farmers. D 2004 Elsevier B.V. All rights reserved.