Dual Benefits of Whey Protein Concentrate in a Microencapsulated Diet for Larval White Shrimp, Litopenaeus vannamei

Abstract

In this work a larval shrimp diet was spray-dried using a ratio of 75% whey protein concentrate and 25% mesquite gum as wall material, where the sole protein contribution to the diet was the whey protein concentrate. The microencapsulated diet exhibited the following physical properties: mean volumetric particle size of 49.3 µm, characteristic floatability time 225.3 min, and density of 606 g/l. Its outer morphology was characterized by a dimpled spherical shape with no evident surface pores or cracks. Inner microstructure showed a central void, with the feed components finely embedded in the wall matrix. Two bioassays were performed with zoea of white shrimp Litopenaeus vannamei. In the first study, microencapsulated diet, and microencapsulated diet plus a single dose of live algae, were compared with a live algae control diet; in the second study, three co-feeding regimes consisting of microencapsulated diet + 10, 30 and 60 C. muelleri cells/ µl, respectively, were compared with the live algae control diet. In overall terms, the co-feeding regime with 30 cells/ µl produced larvae with carapace length (0.74-mm Cl) and development index (4.5 DI) significantly superior to that of the live algae treatment (0.70- mm Cl, 4.1 DI; respectively), and yielded similar individual dry weight (34-µg DW) and survival rate (58%). These results indicate that microencapsulated diets supplemented with live algae can produce responses similar to those of live feed. These results further indicate that whey protein concentrate is a good protein source as well as a wall forming agent for microencapsulating shrimp larval diets.