progress
November 2014
Task 12.2: Influence of broodstock feeding regimes for fecundity and spawn quality (led by IEO)
A great advance was obtained this year in collecting information about the biochemical level of different tissues of wild fish that will contribute the development of a specific formulation for wreckfish broodstock. A total of 60 fish were sampled between February and October of 2014 in the fish market in two places in Galicia although the fish came from the same fishing area, the Azores. Some biometric parameters were obtained (total length, total and eviscerated weight, perimeter, % of the perivisceral fat and gonadosomatic and hepatosomatic index). Fish dissection and sample collection of muscle, liver and gonads were carried out to know the nutritional status of wild fish. Total weight varied between 3.6 and 18 Kg and total length varied between 56 and 98 cm and no relation was observed between weight, sex and perivisceral fat.
Task 12.2: Influence of broodstock feeding regimes for fecundity and spawn quality (led by IEO)
A great advance was obtained this year in collecting information about the biochemical level of different tissues of wild fish that will contribute the development of a specific formulation for wreckfish broodstock. A total of 60 fish were sampled between February and October of 2014 in the fish market in two places in Galicia although the fish came from the same fishing area, the Azores. Some biometric parameters were obtained (total length, total and eviscerated weight, perimeter, % of the perivisceral fat and gonadosomatic and hepatosomatic index). Fish dissection and sample collection of muscle, liver and gonads were carried out to know the nutritional status of wild fish. Total weight varied between 3.6 and 18 Kg and total length varied between 56 and 98 cm and no relation was observed between weight, sex and perivisceral fat.
Concerning biochemical composition the first results showed that on wild wreckfish the level of proteins and lipids in muscle vary between 74-96% and 3-14% respectively. In liver and gonad a high variability was observed: 19-69% in proteins of liver and 10-80% in gonad. Lipid content vary among 15-73% and 9-90% in liver and gonad respectively. The fatty acid profile (% of total fatty acids) of muscle, liver and gonad were obtained. In muscle PUFA, SFA and MUFA fractions are among 36-46%, 28-30% and 25-33% respectively, n-3 PUFA content reached 32-40%, EPA value reached a mean value of 4.3%, DHA 26.2% and ARA 3%. The liver fatty acid profile showed a high variability: PUFA levels were 4-33%, SFAs 21-41% and MUFA 37-69%. n-3 PUFA, n-6 PUFA, EPA, DHA and ARA represent a lesser percentage of total fatty acids that it was found in muscle. In gonad, PUFA content represent 23-37%, SFAs 27-31% and MUFA 36-50%, n-3 PUFA reached 20-29 % of total fatty acids, n-6 PUFA the 3-7%, EPA content had a mean value of 4.5%, DHA 16.3% and ARA 2.9%. First results about biochemical composition of wild wreckfish evidenced the differences in lipid content between these and those cultured, which are very noticeable in muscle with mean values of 23% in cultured fish and 6% in wild fish but it is necessary to carry out more analysis of cultured fish to confirm these results.
With respect to the influence of the broodstock food composition on the reproductive development, some samples of semimoisture diet were collected. This diet is supplied to the IEO broodstock and is a mixture of: % 14.8% white fish,14.8% oily fish 14.8%, mussel 18%, squid 17.6% and fishmeal 24.8%. The first results of its lipid composition showed that lipid level was 14-16%. The PUFA level reached 35-39%, SFAs 29-32% and MUFA 32-34%; EPA represented 9-10%, DHA 14-16% and ARA 1-2%.
The effect on the reproductive development of three feeding regimes: semimoisture diet, commercial dry food (Vitalis Repro and Vitalis Cal) and a new dry food specifically formulated for wreckfish, will be compared in the next years.
With respect to the influence of the broodstock food composition on the reproductive development, some samples of semimoisture diet were collected. This diet is supplied to the IEO broodstock and is a mixture of: % 14.8% white fish,14.8% oily fish 14.8%, mussel 18%, squid 17.6% and fishmeal 24.8%. The first results of its lipid composition showed that lipid level was 14-16%. The PUFA level reached 35-39%, SFAs 29-32% and MUFA 32-34%; EPA represented 9-10%, DHA 14-16% and ARA 1-2%.
The effect on the reproductive development of three feeding regimes: semimoisture diet, commercial dry food (Vitalis Repro and Vitalis Cal) and a new dry food specifically formulated for wreckfish, will be compared in the next years.
Participating organizations (WP leader in bold): P2. FCPCT, P8. IEO and P19. CMRM
Studies on wreckfish nutritional requirements and optimum diets are missing. There are only a few references related to feeding habitats from commercial caught and feeding rates in captivity, but some information can be obtained from studies or results obtained in other species of groupers.
Task 12.1 Live preys and enrichments for wreck fish larvae (led by CMRM). To determine the quality of enrichment products and the effect on wreckfish larvae quality, the following feeding trials will be conducted:
Task 12.2 Influence of broodstock feeding regimes for fecundity and spawn quality (led by IEO). The effect of feeding regimes based on fresh and compound feeds will be studied on wreckfish reproductive performance . Based on wild brood stock feeding habits. The studies will focus particularly on protein/energy ratios and essential fatty acid levels. The best feeding regime will be combined with the best induction protocol in Task 6.3. to optimize the effectiveness of the spawning induction protocols. Effects on fecundity and egg and sperm quality will be determined. Effect of dietary nutrients levels on embryogenesis and biochemical composition of eggs from the former trials will also be examined.
Studies on wreckfish nutritional requirements and optimum diets are missing. There are only a few references related to feeding habitats from commercial caught and feeding rates in captivity, but some information can be obtained from studies or results obtained in other species of groupers.
Task 12.1 Live preys and enrichments for wreck fish larvae (led by CMRM). To determine the quality of enrichment products and the effect on wreckfish larvae quality, the following feeding trials will be conducted:
- Sub-task 12.1.1 Some enrichment products will be developed for live food for larval wreckfish. The first study will focus on EFA content in live preys, since this is one of the main factors affecting marine fish larval survival and growth . The influence of the different live food enrichments on the nutritional composition of the larvae will be studied. Biochemical analysis of samples of live food as well as larvae from the different trials will be done in triplicates.
- Sub-task 12.1.2 This Sub-task will depend on the results obtained above and will focus on either fat-soluble vitamins or antioxidants in different enrichment products . The effect of enrichments nutritional quality on nutritional quality on larvae composition will be studied, as well as the biochemical analysis of samples from the former trials. All the biochemical analysis will be done in triplicates.
Task 12.2 Influence of broodstock feeding regimes for fecundity and spawn quality (led by IEO). The effect of feeding regimes based on fresh and compound feeds will be studied on wreckfish reproductive performance . Based on wild brood stock feeding habits. The studies will focus particularly on protein/energy ratios and essential fatty acid levels. The best feeding regime will be combined with the best induction protocol in Task 6.3. to optimize the effectiveness of the spawning induction protocols. Effects on fecundity and egg and sperm quality will be determined. Effect of dietary nutrients levels on embryogenesis and biochemical composition of eggs from the former trials will also be examined.