Development of lipid microbeads for delivery of lipid and water-soluble materials to Artemia

doi:10.1016/j.aquaculture.2007.09.031

Aquaculture

Volume 273, Issue 4, 20 December 2007, Pages 614-623

https://doi.org/10.1016/j.aquaculture.2007.09.031 Get rights and content

Abstract

Lipid spray beads (LSB) containing high concentrations of phospholipids were produced in order to improve their dispersion in both fresh and saltwater. The beads were developed to deliver both fat-soluble and water-soluble micronutrients to Artemia and other suspension feeders. LSB were prepared by spraying molted lipid into a chamber that was cooled with liquid nitrogen in order to solidify the lipid beads. Addition of soy lecithin to LSB did not affect retention of glycine when the beads were suspended in distilled water. There was an initial loss of 80% incorporated glycine after LSB were suspended in water for 20min. Artemia readily ingested riboflavin-containing LSB and their full guts were evident within 30min of feeding. The riboflavin content of Artemia could be increased from 55 ± 0.6 mg kg^− 1 (dw) to 329 ± 62 mg kg^− 1 (dw) after 1h enrichment. LSB prepared with phospholipids are promising vehicles for enrichment of suspension-feeding organisms used as feed for larval marine fish and crustaceans as well as other suspension feeders.

Introduction

Compared with natural zooplankton prey, such as copepods, Artemia are deficient in several water-soluble micronutrients that may be necessary for high growth and survival of marine fish larvae (Van der Meeren, 2003, Moren et al., 2006, Hamre et al., 2007). Enrichment of Artemia with water-soluble micronutrients is commonly achieved by either direct addition of micronutrients to the culture water or by adding micronutrients to lipid emulsions fed to Artemia cultures. The current enrichment methods are not optimal due to low uptake efficiencies and a failure to increase micronutrient concentrations to desired levels (Hamre, unpublished results). Enrichment of Artemia with liposomes has been successful (Tonheim et al., 2000, Monroig et al., 2003, Monroig et al., 2006), but production of large quantities of liposomes is both expensive and technically difficult.

Incorporation of nutrients in a lipid matrix can be accomplished by a method referred to as spray chilling. Molten lipid, containing the active ingredients, is sprayed into a cooled environment where the lipid beads harden. The lipid beads consist of active ingredients randomly distributed in the lipid matrix with some possibly protruding through the surface of the beads. This is in contrast to truly encapsulated material where ingredients are surrounded with an intact wall (see review by Gouin, 2004).

Spray chilling is a commonly used technology in pharmacy and food technology where it has been used for sustained release (Akiyama et al., 1993), taste masking (Yajima et al., 1999), improving stability (Schwendeman et al., 1998) and encapsulation of vitamins and minerals (Gibbs et al., 1999). The development and use of LSB to deliver water-soluble nutrients to marine fish larvae has been successfully accomplished using triacylglyceride (TAG) LSB that were themselves incorporated in a zein-bound feed particle (Önal and Langdon, 2005a, Önal and Langdon, 2005b). Encapsulation of water-soluble nutrients in LSB significantly decreased leaching (Önal and Langdon, 2005a).

The method to produce LSB by spray chilling requires that the lipid is solid at low (< 20 °C) temperatures; therefore, it is not possible to deliver significant proportions of unsaturated fatty acids as TAG because they typically have low melting points. In contrast, phospholipids, such as soy lecithin, often have high proportions of unsaturated fatty acids (58% linoleic acid and 8% linolenic acid; Wettstein et al., 2000), but melting temperatures are elevated compared to those of free fatty acids or triacylglycerols due to the presence of the phosphorus group. This characteristic of phospholipids makes them good candidates for making LSB that are solid at room temperature, but have a high content of unsaturated fatty acids. In addition, several studies have shown that marine fish larvae benefit from inclusion of phospholipids as a dietary lipid source (Kanazawa et al., 1983a, Kanazawa et al., 1983b, Cahu et al., 2003).

The goal of this study was to evaluate the effects of additions of soy lecithin on the characteristics of LSB designed to deliver micronutrients to enrich Artemia, a common live feed for rearing marine fish larvae.

Section snippets

Production of LSB with different concentrations of soy lecithin

Menhaden stearine was used as the major lipid source in experiments to determine the effects of additions of soy lecithin on the properties of LSB. Menhaden stearine is a by-product of menhaden oil refining and has the consistency of peanut butter and a melting point of 43°C. LSB were prepared using a modification of the method described by Önal and Langdon, 2000, Önal and Langdon, 2004a). Briefly, this method involved mixing core materials with molten lipid and then spraying the mixture into a

Dispersion of LSB and effect on leakage rate

LSB containing aqueous slurry of glycine and 0%, 1% or 5% soy lecithin (Table 2), did not disperse in either salt or freshwater, but clumped immediately. In contrast, LSB containing dry particulate glycine and 40% soy lecithin (Table 1) dispersed in both fresh and salt water while LSB prepared with less than 40% lecithin (Table 1) did not disperse in either fresh or sea water (Fig. 1). LSB containing paraffin wax and 54.5% lecithin (Table 3) dispersed well in both fresh and saltwater.

Addition

Discussion

Önal and Langdon (2005b) showed that LSB made of triacylglycerol were hydrophobic and that the LSB clumped and did not disperse in aqueous solution. By inclusion of high concentrations of phospholipids in the LSB, we were able to produce LSB that dispersed freely and were vehicles for delivering both lipid and water-soluble compounds to suspension feeders, such as Artemia. Addition of phospholipids can also increase the concentration of unsaturated fatty acids in LSB without causing a decrease

Acknowledgements

Brendan Clack (Oregon State University) is thanked for teaching the first author the method for producing LSB and Ephraim Temple (Oregon State University) for additional help. We would like to thank Kjersti Ask (NIFES) for analysis of riboflavin. The first author acknowledges the financial support by the Research Council of Norway, project number 14768/120 and project number 169558.

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Development of lipid microbeads for delivery of lipid and water-soluble materials to Artemia

Abstract

Introduction

Section snippets

Production of LSB with different concentrations of soy lecithin

Dispersion of LSB and effect on leakage rate

Discussion

Acknowledgements

J. Control. Release

Anal. Biochem.

Aquaculture

Trends Food Sci. Technol.

Aquaculture

Aquaculture

Aquaculture

Aquaculture

Aquaculture

Aquaculture

Aquaculture

Aquaculture

Anim. Feed Sci. Technol.

The need for riboflavin supplementation in high and low energy diets for Atlantic salmon (Salmo salar L.) parr

Aquac. Nutr.

Evaluation of lipid spray beads for the delivery of water-soluble materials to a marine suspension-feeder, the Manila clam (Deshayes 1853)

Aquac. Nutr.

Effect of dietary phospholipid level and phospholipid: neutral lipid value on the development of sea bass (Dicentrarchus labrax) larvae fed a compound diet

Br. J. Nutr.

Artemia bioencapsulation I. Effect of particle sizes on the filtering behavior of Artemia franciscana

J. Crustac. Biol.

Bioencapsulation in Artemia: II. Influences of the particle concentration in the enrichment process

Aquaculture