3. The method has been successfully applied to evaluating proteins for salmonids and white
shrimp
• Although the spectrum of digestive enzymes in fish is not distinctive from land animals, the
homologues exhibit several different properties
• This may explain why their use better predicts protein digestibility than commercially
available digestive proteases from mammals
- Cod pepsins are activated by NaCl vs porcine pepsins are inhibited
- Salmonid trypsins are several orders of magnitude more sensitive to soy bean trypsin inhibitor than the
enzyme from mammals
② Use of enzymes to improve feed quality
1. To upgrade poor-quality raw materials and/or to pretreat the feed material with enzymes
rather than including the enzymes in the diet formulation
2. The feed value of canola meal for juvenile prawns was improved by adding a mixture of
enzymes to the diet
3. Pretreatment of soybean residue with papain yielded significantly better carp growth and
reduced water turbidity of the fish tanks
4. Pretratment of soybean meal with phytase increased dietary phosphorous availability for
rainbow trout