This report is closed.
Use of canola oil in winter feed for salmon in the sea / Use of canola oil in winterdiets for Atlantic salmon
An experiment was performed with different amounts of rapeseed oil (0, 50 and 80%) in winter feed for 570 grams of salmon raised in the sea with 28.2 ‰ salt (26 - 34 ‰) at an average temperature of 4.5˚C (3.8 - 5 , 6˚C). The fish doubled in weight during the 152-day trial period. TGC3 was an average of 2.9. The fat content of the feed had very little effect on the growth, feed intake, feed utilization and volume content of fish fillets. The composition of the feed fat did not have much effect on the color of the fillets, although fish that were fed only fish oil gave significantly (p = 0.017) lighter fillets than fish that were fed with rapeseed oil. The type of fat in the feed, however, had a significant effect on the fatty acid composition of the fat in both the feed and the fat in the fillets, especially the EPA, DHA content and the ratio of n-6 and n-3 fatty acids. However, the results show that the effect in the fillet fat is much smaller than in the feed fat, especially with the fatty acid DHA. It seems that DHA converts feed fat into fillet fat rather than using it as an energy source.
An experiment with different inclusion of Canola oil (0, 50 and 80%) in diets for 570 grams Atlantic salmon that was reared in sea water with average salinity of 28.2 ‰ (26 - 34 ‰) at average temperature of 4.5˚ C (3.8 - 5.6˚C). The fish doubled its weight during the 152 days trial period. TGC3 was on average 2.9. The fat type had had only minor effects on growth, feed intake, feed conversion and nutrient content in filet. The fat type in the diet did not have much effect on the filet color even though the fish that got feed with fish oil was significantly (p = 0.017) lighter in filet color than fish that got diets with Canola oil. Composition of the diets had market effect on the fatty acid composition of both dietary fat and filet fat in particular the content of EPA and DHA and the n ‐ 6 to n ‐ 3 ratio. However the results show lower effect in the filet fat than in the dietary fat, particularly regarding the content of DHA indicating that the fish is directing that fatty acid towards the storage lipid in the filet rather than using it as energy source.
Optimization of Icelandic turbot culture / Profitability increase in Icelandic sandeel farming
The main goal of the project "Increasing profitability in Icelandic sandeel farming (MAXIMUS)" was to develop methods to reduce production costs in sandeel farming in Iceland. Sandhverfa is for the most part raised in pots on land and is therefore very suitable for farming in Iceland, in addition to which the market price is high (about 1500 ISK / kg) and stable. Land farming, on the other hand, is costly and therefore new and better technical solutions must be sought to increase the efficiency of farming. The MAXIMUS project worked on the development of a new light cycle control that makes it possible to increase growth by up to 20%. Work was done on the development of new feed types which sought to reduce the weight of sea protein and managed to reduce feed costs by up to 10% compared to conventional feed. This will make it possible to increase the efficiency of aquaculture in the later stages of the aquaculture process. The project also developed a multiplex genetic marker kit for a sandeel that has made it possible to genotype large numbers of juveniles quickly and safely. This genetic marker kit will be used to accelerate genetic progress in sandeel farming in the future. Market research was carried out and an attempt was made to examine the future prospects of the farm. Sandeel production will probably increase considerably in the coming years, but despite an increase in recent years, prices have remained stable. The results of the project strongly indicate that sandeel farming is economical in Iceland and the methods that have been developed in the project will increase the likelihood of development and investment in sandeel farming in Iceland.
The overall aim of this project, MAXIMUS, was to develop methods to significantly reduce production costs in farming of turbot (Scophthalmus maximus). Production of turbot in Iceland has been growing and therefore it is important to develop technology to lower the production costs. Turbot is an ideal species for farming in land ‐ based stations in Iceland, having many good characteristics as an aquaculture species and high (1500 kr / kg) and stable market value. Rearing fish in land ‐ based farms comes however with a cost and it is important to constantly strive to develop new technology to reduce cost of production. Firstly, methods to use photoperiod control to increase growth rate up to 20% compared to traditional methods were developed. Secondly, it was found that crude protein in turbot feed can be reduced by approximately 10% compared to current level in commercial feed without negative effects on growth. This will make production of a more cost efficient and less expensive feed for large turbot possible. Thirdly, multiplex genotyping systems were developed, making it possible to determine the pedigree of the parent fish during breeding to ensure genetic diversity leading to high growth rate. Finally, the current and future developments in turbot production and markets were analyzed. Production of this species is likely to increase considerably in coming years. In addition, there are important developments in technology that may impact on future supply and cost of production. An estimate of the economic implications of optimized turbot farming system in Iceland, profitability and revenue, was also investigated. Overall the results from this project will make turbot production in Iceland more feasible, and profitable, in the future.
Report closed until 01.12.2013
Coloring of Arctic charr / Coloring of charr hold
An experiment was carried out with the aim of evaluating the activity of an organic pigment, Ecotone ™, and an inorganic pigment, Lucantin® Pink, on the coloration of char meat. The effect of 25% and 30% fat in feed on the activity of the pigments was also studied. All experimental items were tested in triplicate. The mean weight of the experimental fish was 564 g at the beginning of the experiment and 1381 g at the end of the experiment after 131 days. The temperature during the experimental period averaged 8 C̊ and the salinity of the broth was 20 ‰. The digestibility of astaxanthin in Lucantin® Pink was much higher than in Ecotone ™. The difference in body color measured by different methods turned out to be much smaller, which indicates a better utilization of the color in Lucantin® Pink. Little effect on body coloration was found by different amounts of fat in the feed and this was true for both pigments. The organic dye is more expensive to buy than the inorganic one and it results in approx. 5.5 % is more expensive to dye char with Ecotone ™ compared to Lucantin® Pink. During the analysis of the color of the feed at the beginning and at the end of the experiment 16 weeks later, it was found that there was a significant loss of color from the feed and that loss appeared to be independent of the type of color.
A feeding trial was conducted to compare the pigmenting efficiency of the biological colorant Ecotone ™ containg astaxanthin and prepared from the red yeast Phaffia rhodozyma, and the synthetic colorant Lucantin® Pink in Arctic charr. Both colorants were incorporated into diets containing either 25 or 30% lipid. All treatments were run in triplicate. The initial average weight of the fish was 564 g and the final weight 1381 g after a trial period of 131 days at 8 C̊ and 20 ‰ salinity. The digestibility of astaxanthin seems to be very much dependent upon the astaxanthin source. Differences in flesh color indicate a better utilization of astaxanthin from the synthetic source (Lucantin® Pink) as compared to the biological source (Ecotone ™). There was only a minor effect of lipid content on utilization of the astaxanthin. The biological astaxanthin source is more expensive than the synthetic source, resulting in about 5,5% higher production cost of fish produced with the “organic” colorant Ecotone ™ as compared to fish produced with the synthetic source of astaxanthin (Lucantin® Pink). The astaxanthin content in all diets proved to be very unstable when the feed was stored under conditions that are common in production of Arctic charr (10 - 20 ̊C indoors). The loss of astaxanthin ranged from 21-40% and tended to be higher in diets containing Ecotone ™. Thus, it is very important to avoid high temperatures, light and oxygen during storage of the feed.
Fat tolerance of cod
The purpose of this study was to investigate the effect of fat content in feed on the growth and cleaning of cod of different sizes. Knowledge of the nutritional needs of fish is a necessary prerequisite for the preparation of feed for them. Two-size cod (120 g and 600 g) were fed (in triplicate) for 12 weeks on feed containing 10.0%, 13.5%, 21.2%, 24.5% and 27.7% fats in dry matter. Different fat content did not affect growth (SGR), body mass index (CF), fillet utilization, liver fat content or fillet fat content. In the smaller fish, the feed index (FCR) decreased with increased fat in the feed. The feed fat did not affect the fat content of offal without liver in the smaller fish (120g) but in 600 g fish the fat in the intestines increased with increased fat content of the feed. The fat content did not affect the proportion of gutted weight of the total weight in the 600 g fish, but in the smaller fish the proportion decreased with increased fat in the feed. Liver ratio (HSI) in 600g fish was not dependent on the fat content of the feed, but there was a positive correlation between feed fat and HSI in the 120 g fish. This means that the fat tolerance of cod in terms of liver ratio depends on the size of the fish.
Detailed knowledge of the nutritional requirements of fish is essential for feed formulation. The aim of this research was to investigate the effects of different lipid content in diets for Atlantic cod of different size. Cod of two size groups (initial weight 120 grams and 600 grams) were fed, in triplicate, for 12 weeks diets containing 10.0%, 13.5%, 21.2%, 24.5% and 27.7% lipid in dry matter. Different lipid content in the diet did not affect growth (SGR), condition factor (CF), fillet yield, lipid content in liver or lipid content in fillet. In the smaller fish, FCR was reduced with increased diet lipid. The lipid content in the diet did not affect the lipid content of intestines in the 120 grams fish but in the 600 grams fish there was a positive correlation between lipid content in diet and intestines. Dietary lipid did not affect gutted weight (calculated as the percentage of round weight) in the 600 grams fish but in the 120 grams fish, the percent gutted weight decreased with lipid content of the diet. The Heposomatic index (HSI) in the 600 gram fish was not affected by the lipid content of the diet but dietary lipid content significantly affected the HSI in the smaller fish. This indicates that the lipid tolerance of Atlantic cod, with respect to the effect on HSI, is size dependent.
Plant raw materials in charr feed instead of fishmeal and fish oil
The aim of the project was to produce cheap feed for char so that production costs can be reduced and profitability in char farming can be increased. The project consisted of testing different raw materials (especially plant raw materials) instead of fishmeal and fish oil and finding out how large a proportion of them can be in the feed. The condition for success was that the feed was healthy, utilized well by the fish and led to a growth comparable to the current farmed feed and that the feed did not have a negative effect on the quality of the product, in terms of chemical content (fatty acid, color) and physical properties (taste, color, density). Different types of feed were tested as a starter feed for charr juveniles, which is a new approach, in order to get an overview of the possible amount of different raw materials. The most interesting types of feed from those experiments were then tested in experiments on larger chars to confirm the results and to examine the effect on the quality of the products. The results of the experiments with different protein ingredients confirmed that high quality fishmeal (Superior) is a very good source of protein in feed for char. The charr's possibilities of utilizing soybean meal seem to be limited, as in the case of salmon, ie. ≤ 15% incorporation into the feed. The possible use of maize gluten meal appears to be ≤ 18% in starter feeding but could not be tested on larger fish. The reaction of char to rapeseed meal as a protein source, however, was positive and in fact better than expected considering that there has not been a good word for this raw material in feed for other salmonids. Regarding fat sources in charr feed, the results of the project show that different fat sources can be used with acceptable results. Juveniles, on the other hand, seem to have somewhat stricter requirements for fat sources than larger fish. This is especially evident in the effect on growth rate. The results of the experiments with fat sources also show that the composition of the fat source has a decisive effect on the fat composition of the fish as well as various sensory evaluation factors in the product. The main conclusion, however, is that it is possible, within certain limits, to use different fat sources in charr feed. In particular, it seems that palm oil can be used extensively.
The objective of the project was to produce economic feed for Arctic charr to decrease production cost and increase profitability in Arctic charr farming. The project investigated the possibilities of replacing fishmeal and fish oil with raw materials of plant origin, and to find out the limits for their use as feed ingredients. The criteria was that the feed should ensure maximum health, optimize utilization of feed and growth should be comparable to growth obtained by feed currently used. Neither should the feed have adverse effects on product quality, especially regarding fatty acids composition and physical properties (taste, flesh-color, texture). Effect of different raw materials was screened in start feeding trails using Arctic charr larvae. The most interesting raw material combinations were thereafter tested in trials with bigger fish in order to confirm the results of the start feeding trials and investigate the effect of the combinations on slaughter quality of the Arctic charr. The results of the trials with different protein raw materials confirmed that high quality fishmeal (Superior) is a very good protein source for Arctic charr. Arctic charr seems to have limited ability to utilize soybean meal and the inclusion should be limited to ≤ 15% in the diet, similar to the limits that are common for Atlantic salmon diets. The limits for use of Corn gluten meal in starter diets seem to be ≤ 18% but this raw material was not tested in bigger fish. The response of Arctic charr to the use of rapeseed meal as a protein source was positive and even as high inclusion as 30% in the diet did not have negative effect on growth. The main findings of the project regarding use of lipid sources is that it is possible to use different sources with reasonable effect in feed for Arctic charr. Of particular interest is the effect of palm oil. Arctic charr larvae seem to be more demanding, regarding use of lipid sources, than bigger fish. The results clearly demonstrate the effect of fatty acid (FA) composition of the lipid sources on the FA composition of the fish and it is possible to change the FA profile with different lipid sources. Different lipid sources also have marked effects on different sensory traits in the farmed Arctic charr.