Food composition and digestive enzymes in the gut of the African electric catfish Malapterurus electricus (Gmelin 1789) (Malapteruridae)

Analyses of stomach contents of 330 Malapterurus electricus (standard length, 10.1-30.5 cm) in Mahin Lagoon (southwestern Nigeria) established it as a bottom feeder. There was a preponderance of insects accounting for >80% occurrence and >25% of total volume in stomachs of specimens, suggesting a stenophagous predatory habit. Qualitative and quantitative assays of digestive enzymes in the different regions of the gut (oesophagus, stomach, duodenum, ileum, rectum) were investigated. Carbohydrases (amylase, maltase), chitinase, proteases (pepsin, chymotrypsin, trypsin) and lipases were detected in different gut regions with different activity. The pattern of distribution and relative activity of the enzymes correlated with the predatory diet

Functional properties of enzymatically modified protein from fish waste

Fish flour from dried waste consisting of head, tail, fins and entrails was enzimatically hydrolysed using various proteases and the hydrolysate was spray dried. The functional properties such as water-fat absorption ratio, foaming and solubility index of the hydrolysates and fish flour revealed that some of the products might find significant uses in the food and/or cosmetics industry. Electrophoretic separation of the proteins from the fish flour and of the hydrolysates indicated that almost all the flour proteins are susceptible to proteolytic cleavage with the exception of one or two. The extent of degree of hydrolysis from 43-70.3% with a simultaneous decrease in unpleasant smell suggest an economical tool for minimizing odour pollution due to fish industry waste deterioration.

Effect of fertilizer carbamide on proteolytic enzymes of fish Labeo rohita

Specific activities of acid, alkaline and neutral proteases in liver, muscle, brain, and gill of fish exposed to 50 ppm ambient carbamide for 15, 30 and 60 days and in control were estimated. It was observed that carbamide even at low concentration of 50 ppm inhibited proteolysis and favoured protein synthesis.