TOPCOD, OPTILAR / Long live the first model. Preferred breeding processes in larval and juvenile farming of cod
Recent research has shown that the best conditions for the production of larvae produce juveniles of better quality and that the growth advantage in the early stages of rearing pays off to some extent in the later stages of growth. The main goal of this project is to define the best conditions for cod cod farming in Iceland and to that end use various methods to solve the main problems associated with the production of cod larvae today. This report discusses the work components that Matís ohf. participated in, among other things, researching the effects of enrichment of feed animals with supplementary bacteria and protein digestion on the growth, development, immune stimulation and digestive flora of larvae, as well as research on the effects of different primary feeds on muscle growth carried out in collaboration with the MRI. The results indicate that the start of dry feed feeding late or around 50 dph does not give the larvae a growth advantage and that it is sufficient to feed Artemia up to 40 dph. Dry feed from 30 dph led to lower growth and an increased incidence of structural defects. Enrichment of feed animals with a lyophilized mixture of two complementary bacterial strains did not affect the composition of bacterial flora larvae and strains did not gain a foothold in treated larvae. However, poor roe quality can be expected to have affected treatment outcomes. The results of experiments confirm previous results on the positive effect of enrichment of feed animals with protein digestion on the performance and development of larvae.
Recent research has demonstrated that production optimization during the larval and juvenile phase will to some extent be reflected in the performance of the fish during the ongrowing phase. The objectives of the project are to optimize the larval production of Atlantic cod in Iceland by applying a multidisciplinary approach to solve central bottlenecks related to larval production. This report presents tasks where Matis ohf. was involved, including analyzes of the effects of live prey enrichment using putative probionts and a fish protein hydrolyzate on larval survival quality immune stimulation and intestinal bacterial community of larvae. The study also involved an analysis of the effect of startfeeding protocols on muscle growth in collaboration with MRI. The results indicate that late weaning around 50 dph may be excessive and produce no significant advantage. An intermediate weaning strategy, with brine shrimp feeding up to 40 dph, appears to be sufficient to convey important advantages in terms of growth and anatomy. Early weaning at 30 dph produced slow ‐ growing juveniles and a higher deformity ratio. Using the freeze dried preparations of the probionts did not affect the bacterial community structure of larvae and the probionts were not found to be established within the bacterial community of treated larvae. Poor quality egg may, however, partly explain the lack of effects as a result of treatment. The present study confirms the results of previous studies where live prey enrichment using a fish peptide hydrolyzate significantly improved larval survival and development.
