Bacterial Degradation of Microencapsulated Foods Used in Larval Culture

Abstract

Microencapsulated foods are widely used in the culture of larval fish, bivalves and crustaceans. The resistance to bacterial decay of two of these diets was investigated under microbial conditions similar to those found in hatchery cultures of larval penaeid prawndshrimps. A 2–3‐fold increase in total ammonia concentration and a 7–14‐fold increase in total bacterial numbers were detected within 48h when microcapsules were added to larval culture water at a density recommended by the manufacturer for one day of supplementary feeding. Increased dissolved total ammonia and bacterial populations were detected within 1.5h of addition of food to penaeid larval culture water. Scenning electron microscopy indicated that microcapsules were colonized by numerous bacterial cells within 1h. Physical disintegration of microcapsules occurred after 6 to 12h. Only in sterilized penaeid larval culture water did microcapsules remain intact for a significant period. These findings are discussed in relation to development of improved methods of larval culture.

Biosecure Shrimp Feeds and Feeding Practices: Guidelines for Future Development

“…There is no nutrient or naturally occurring substance (including enzymes, hormones, pigments, polysaccharides, organic acids, or beneficial microflora) present with live foods and/or fresh natural feed items such as marine polychaetes, Artemia , or squid that cannot be put into a fully biosecure commercially formulated dry, semi‐moist, or liquid shrimp feed. For a review of recent studies concerning the replacement of live and/or fresh natural food items see: Broodstock feeds: Summavielle et al ; Mendoza et al ; Du et al , , ; Perez‐Velazquez et al ; Wouters et al ; Fegan ; Bao‐Shuenn et al ; Meunpol et al , , ; Zhou et al ; Saito et al ; Paibulkichakul et al ; Wu et al ; Matinfar et al ; Argueello‐Guevara and Molina‐Poveda ; Chimsung ; Dhert ; Ortiz Larval feeds: Jones et al ; Galgani and Aquacop ; Coutteau et al ; Muir and Sutton ; Jaime et al , ; Garcia‐Ortega et al ; Jones ; Samocha et al ; Medina‐Reyna et al ; D'souza et al ; Gallardo et al ; Calderon et al ; Fegan ; Robinson et al ; Wang and Mai ; D'Abramo et al ; Jaime‐Ceballos et al , ; Zeng and Wang ; Sirvas‐Cornejo et al ; Gamboa‐Delgado and Le Vay ; Ramya and Felix ; Xie et al , ; Anh et al ; Ghaen et al ; Dhert ; Naessens et al …”

Replacement of live feed by formulated feed: effect on the growth and spawning performance of Siamese fighting fish (Betta splendens, Regan, 1910)

“…The use of dry feeds typically requires an increased water exchange and supplemental aeration to maintain the food particles in suspension. Constant monitoring of culture water is also required to avoid a decline in water quality due to residual and uneaten feed (Muir & Sutton 1994). The development of nutritionally stable inert feeds could reduce operational costs in hatcheries by minimizing the reliance on LFs with variable nutrient composition (Robinson, Samocha, Fox, Gandy & Mckee 2005).…”

Chitosan as a wall material for a microencapsulated delivery system for Macrobrachium rosenbergii (de Man) larvae

“…However, the high cost of these protein-walled microcapsules, use of organic solvents and highly reactive chemical cross-linking agents diminish their long-term prospects of commercial production and use (Langdon 2003). Moreover, a high bacterial load associated with the breakdown of commercial diets encapsulated within cross-linked, protein-walled capsules has also been reported (Muir & Sutton 1994). The main advantages of chitosan compared with the cross-linked protein wall materials are its non-toxicity, formation of ¢lms soluble in acidic pH and well-documented antibacterial property (Allan & Hadwiger 1979;Kendra & Hadwiger 1984;Sudarshan, Hoover & Knorr 1992;Wang 1992;Roller & Covill 1999;Zheng & Zhu 2003).…”