Tag: Probiotics

Reports

TOPCOD, OPTILAR / Long live the first model. Preferred breeding processes in larval and juvenile farming of cod

Published:

01/04/2011

Authors:

Jónína Jóhannsdóttir, Agnar Steinarsson, Rannveig Björnsdóttir

Supported by:

Technology Development Fund and AVS R&D Fund of Ministry of Fisheries in Iceland

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. 

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Reports

Production of wheeled animals for cod farming / Production of quality rotators for breeding cod fry

Published:

01/03/2009

Authors:

Jónína Þ Jóhannsdóttir, Agnar Steinarsson, Rannveig Björnsdóttir

Supported by:

Nordic-Atlantic co-operation (NORA)

Production of wheeled animals for cod farming / Production of quality rotators for breeding cod fry

There is great interest in finding ways to control farming conditions at all stages of aquaculture. The control of microbial flora in the environment and the gastrointestinal tract of larvae is, among other things, thought to be able to reduce losses that occur in the early stages of marine fish farming. A large number of bacteria usually accompanies feed animals in cod farming, but the use of recycling systems in the breeding of equidae has, among other things, the advantage that a smaller number of bacteria gain a foothold in the systems compared to batch farming. The use of bacterial flora for bacterial flora control has increased significantly in recent years and has in some cases contributed to increased growth and quality of larvae. In addition to strengthening co-operation between cod juvenile producers in the Nordic countries, the aim of the project is to develop methods that increase stability and efficiency in the production of feed animals. It is based on a recycling system designed by Sintef in Norway and this section investigates the effects and presence of selected beneficial bacteria in the system. The main results of treatment with two selected bacterial strains showed that the wheeled animals tolerated the treatment well and an increased crop of animals was obtained when treated with the bacteria in lyophilized form. There was a significant decrease in the number of bacteria in the purgatory during treatment with liquid bacterial culture and the number of bacteria in the purgatory did not reach the initial number during the experiment, but there was some increase in the number of lactic acid bacteria. Although the amount of lactic acid bacteria in equidae only increased after treatment, the bacterial strains did not gain a foothold in the system or lead to changes in the composition of the bacterial flora when treated at this concentration. The project is funded by Nordisk Atlantsamarbejde (NORA) and worked in collaboration with Matís, the Marine Research Institute, SINTEF, Fiskaaling, IceCod and Stofnfisk as well as Nordland Marin Yngel.

There is an increasing interest in controlling environmental parameters during the first production stages of aquaculture and controlling bacterial numbers is among various environmental parameters that are believed to promote increased survival of larvae. Elevated bacterial numbers are introduced into the system through the live feed, but numbers of bacteria have been found to be greatly reduced by the use of recirculation culturing system as compared with batch culturing systems. Furthermore, the use of potentially probiotic bacteria in aquaculture has increased over the past years and has in some cases contributed to increased growth and quality of marine larvae. In addition to promoting collaboration between cod producers within the Nordic countries, the main goal of the current project is to develop methods for stable and advantageous production of live feed animals (rotifers). The project is based on a recirculation culturing system engineered by SINTEF and the present part of the project deals with the effect of treatment and persistence of selected probiotic bacterial strains in the system. The overall results indicate that the rotifer cultures were not negatively affected by the bacterial treatment and treatment using freeze-dried preparations of the two probiotic strains even resulted in improved harvesting of the live feed. A drop in bacterial numbers within the bio-filter unit was, however, observed following the addition of liquid bacterial cultures, indicating negative effects of the bacteria on the bacterial community of the bio-filter unit. An increase in the numbers of lactic acid bacteria was observed in the rotifer cultures following treatment, but the probiotic bacterial strains were neither found to become established as a part of nor affect the dominating bacterial community of the system using the concentrations applied. The project was supported by the Nordisk Atlantsamarbejde (NORA) and is a collaboration between Matís, Hafrannsóknastofnun, SINTEF, Fiskaaling, IceCod, Stofnfiskur and Nordland Marin Yngel.

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