Effect of differently lipid-enriched live feed on growth, survival, and lipid composition of two larval gadoids: Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)

• Main Author: Garcia, Alexandre Sachsida
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2006
• Subjects: atlantic cod; Gadus morhua; Rotifer
• Online Access: https://research.library.mun.ca/10530/; https://research.library.mun.ca/10530/1/Garcia_AlexandreSachsida.pdf

Dietary lipids are recognized as one of the most important nutritional factors that affect fish larval growth and survival. Rotifers and Artemia sp. are widely used as live-feed during the larviculture of marine fish species. However, these organisms are naturally poor in essential fatty acids, and provide only sub-optimum nutrition to the larvae. The present thesis evaluated the use of commercial products for the enrichment of rotifers and Artemia, and the effects of these enriched live-feed on the early growth, survival and lipid composition of Atlantic cod and haddock larvae. For both species the enrichments tested during the rotifer phase were: 1) AlgaMac 2000®, 2) AquaGrow® Advantage, and 3) a combination of Pavlova sp. paste and AlgaMac 2000®. During the Artemia phase of cod larviculture, the same three treatments were tested in addition to a combination of DC DHA Selco® + AlgaMac 2000® as a fourth treatment. Treatments two, three, and four were tested during the Artemia phase of haddock larviculture. Larvae from both species performed better when fed with rotifers enriched with a combination of Pavlova sp. and AlgaMac 2000. At the end of the rotifer phase, larval dry weight ranged from 1.03 to 1.50 mg for cod, and from 1.03 to 1.10 mg for haddock. The larval lipid composition of both species was affected differently by the treatments. During the rotifer phase, larvae from both species maintained high levels of DHA (22:6ω3) while levels of EPA (20:5ω3) decreased significantly. During the Artemia phase, cod larvae fed with AlgaMac 2000-enriched Artemia and haddock larvae fed with DC DHA Selco + AlgaMac 2000-enriched Artemia showed the best overall performance. The cod larvae final dry weight ranged from 5.31 to 12.06 mg, and haddock larvae final dry weight ranged from 4.47 to 6.40 mg. Larvae from both species had their lipid composition affected differently by the treatments. However, in contrast to the rotifer phase, during the Artemia phase, larvae from both species accumulated EPA and reduced DHA levels. ...