Finfish broodstock nutrition and impacts on reproductive output in Atlantic Cod (Gadus morhua)

• Main Author: Webb, Matthew
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2014
• Subjects: atlantic cod; Gadus morhua
• Online Access: https://research.library.mun.ca/6276/; https://research.library.mun.ca/6276/1/Matt%20Webb%20thesis%20Final%202014.pdf

In aquaculture, broodstock nutrition is recognized as an influential factor affecting spawning performance and subsequent egg and larval quality. The purpose of this thesis was to examine broodstock dietary effects on the eggs of fish fed different experimental diets. This study also examined broodstock dietary effects on larval growth using RNA:DNA as predictors of growth. Three diets were tested: an OG diet, an experimental BR diet and a BF diet. The first objective of this work was to categorize the dietary lipid classes and fatty acids in the eggs produced by the broodstock fed these diets. Significant differences were observed between five of the nine dietary lipid classes examined and significant differences were observed in fatty acids (% of total FA) and their ratios among diets for 16 of the 29 dietary fatty acids examined. Of particular importance are, TAG (p = <0.001), PL (p = <0.001), EPA (p = <0.001), DHA:EPA (p = <0.001) and EPA:ARA (p = <0.001). The BF diet which showed the best reproductive output in terms of fertilization and hatching success had the highest proportions of DHA:EPA and the lowest proportions of TAG and EPA. Overall, the differences present in the dietary lipid classes of this study did not translate into differences in the lipid classes of the eggs. Dietary differences were more evident in the essential FA composition of diets and eggs as the proportions of DHA and EPA in the eggs are reflective of the dietary proportions. However, the proportions observed in the eggs are much higher, and the DHA proportions are larger than the EPA proportions, supporting the idea that DHA is preferentially retained in developing yolk-sac larvae. The second objective was to determine if the experimental diets led to any growth benefits in the subsequent larvae. No effects of broodstock diet were observed in larval survival, concentration of nucleic acids, protein concentration or SGR of larvae. The slopes of the RNA:DNA (p = <0.001) after 7 dph showed a significant difference ...