Leaching properties of three different micropaticulate diets and preference of the diets in cod (Gadus morhua L.) larvae

• Published in: Aquaculture
• Main Authors: Kvåle, A., Yúfera, Manuel, Nygård, E., Aursland, K., Harboe, T., Hamre, Kristin
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2005
• Subjects: Microparticulated diet; Hydrolysed protein; Leaching; Atlantic cod; Larvae; atlantic cod; Gadus morhua
• Online Access: http://hdl.handle.net/10261/42970; https://doi.org/10.1016/j.aquaculture.2005.06.002

14 páginas, 3 figuras, 7 tablas. Leakage of water soluble nutrients from larval microparticulated feeds is probably extensive and needs to be further investigated. Leaching rates of 14C-labelled serine, pepsin hydrolysed, protein enriched 14C-algae extract and intact protein enriched 14C-algae extract were measured from three microparticulated feeds for marine fish larvae (heat coagulated, protein bond feed; agglomerated feed; protein encapsulated feed). The effects of particle size (< 0.3 mm, 0.3–0.6 mm; 0.6–1.0 mm) and immersion time (1–60 min) in salt water were also tested. Leaching increased by decreasing molecular weight of leaching component (P < 10− 5), by the feeds in order encapsulated, heat coagulated and agglomerated feeds (P < 10− 5), by longer immersion time (P < 10− 5), and by decreasing feed particle size (P < 10− 5). Due to low protein content of the algae extract, the leaching rates of intact and hydrolysed algae extract did not represent absolute estimates for protein and hydrolysed protein leaching. A new estimate for leakage of hydrolysed protein was calculated based on molecular weight distribution of the hydrolysed algae extract analysed by cutoff centrifugation of the extract. Assuming that molecules < 300–600 or < 9–18 kD would leak, leakage of hydrolysed protein from the smallest feed particles after 5 min immersion would be 80–98%, 43–54% and 4–6% of the agglomerated, heat coagulated and protein encapsulated feeds, respectively. The feeds were also tested for preference in cod larvae of two different sizes (5.6 ± 2.5 mg and 15.8 ± 7.2 mg). The preference was highest for the heat coagulated feed in the first experiment (feed intake 0.32 ± 0.06 mg dry feed larvae− 1) and the agglomerated in the second (2.04 ± 0.32 mg dry feed larvae− 1), while the protein encapsulated feed was preferred at lower rates in both experiments (0.11–0.14 mg dry feed larvae− 1). This study was part of a project financed by the Norwegian Research Council (project no. 115575/120). Peer ...