ISSN:0003-942X    

DOI:10.1080/17450399609381858

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Fatty acids in fish can arise from two sources: synthesisde novofrom non‐lipid carbon sources within the animal, or directly from dietary lipid. Acetyl‐CoA derived mainly from protein can be converted to saturated fatty acids via the combined action of acetyl‐CoA carboxylase and fatty acid synthetase. The actual rate of fatty acid synthesisde novois inversely related to the level of lipid in the diet. Freshwater fish can de‐saturate endogenously‐synthesized fatty acids to monounsaturated fatty acids via a A9 desaturase but lack the necessary enzymes for completede novosynthesis of polyunsaturated fatty acids which must therefore be obtained preformed from the diet. Most freshwater fish species can desaturate and elongate 18:2(n‐6) and 18:3(n‐3) to their C20 and C22 homologues but the pathways involved remain ill‐defined. Cyclooxygenase and lipoxygenase enzymes can convert C20 polyunsaturated fatty acids to a variety of eicosanoid products. The dietary ratio of (n‐3) to (n‐6) polyunsaturated fatty acids influences the pattern of eicosanoids formed. The ß‐oxidation of fatty acids can occur in both mitochondria and peroxisomes but mi‐tochondrial ß‐oxidation is quantitatively more important and can utilise a wide range of fatty acid substrates.

ISSN:0003-942X    

DOI:10.1080/17450399609381859

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Till date, many workers have demonstrated the nutritive value of dietary lipids and the qualitative and quantitative requirements for essential fatty acid (EFA) in many cultivable fish. From the data accrued, a categorization can be made for the EFA requirement as follows: Type I (require n‐6 fatty acids), Type II (require both n‐6 and n‐3 fatty acids) and Type III (require n‐3 fatty acids).

ISSN:0003-942X    

DOI:10.1080/17450399609381860

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The paper summarizes the major morphological signs of nutritional lipid pathologies which have been reported in farmed fish, including nutritional pathologies arising from dietary essential fatty acid (EFA) deficiencies, nutritional pathologies resulting from dietary fatty acid toxicities and imbalances, and nutritional pathologies resulting from the dietary intake of oxidized lipids.

ISSN:0003-942X    

DOI:10.1080/17450399609381861

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Two trials were conducted with duplicate groups of (first feeding) carp larvae fed artificial dry diets based on casein and dextrin over 21 or 25 days. One control diet based on yeast was also tested. Survival, growth and fatty acid profiles of larvae were studied.

ISSN:0003-942X    

DOI:10.1080/17450399609381862

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The stability of the coated lipid fraction of a standard weaning diet was verified by comparing growth and fatty acid incorporation for European sea bass fed diets with an identical formulation but prepared either by extrusion/coating or extrusion only. For each type of experimental diet, a (n‐3) HUFA level of 1 and 2.5% of the dry diet was evaluated. European sea bassDicentrarchus labraxL. were weaned and consequently reared for 23 days on the experimental diets in a recirculation system. A commercial weaning diet served as a control. Final individual dry weight of sea bass larvae weaned and ongrown for a total period of 30 days on the various diets did not differ significantly. The (n‐3) HUFA content of the fish tissue was a reflection of the dietary (n‐3) HUFA content and was not influenced by the technique used to include the essential fatty acids in the diet. The (n‐3) HUFA requirements of European sea bass during and immediately after weaning did not exceed 1% of the dry diet. The combined technique of cooking‐extrusion of a basal diet followed by coating of a lipid emulsion proved to be a valid technique to prepare diets for studying quantitative fatty acid requirements of weaning and first ongrowing stages of marine fish. A standard diet with open formulation is proposed.

ISSN:0003-942X    

DOI:10.1080/17450399609381863

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0003-942X    

DOI:10.1080/17450399609381864

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper examines the effect of different fatty acid composition, together with varying dietary vitamin E contents on fatty acid composition and tocopherol and tocotrienol contents of carp, and compares with other species of fish and the storage quality of the fish produced. Dietary fatty acid composition affected fatty acid patterns of tissues of carp significantly, but this was correlated with the fat content of the diet. Varying the vitamin E content results in no or only very slight variations in the fatty acid pattern of the tissues. The content of α‐tocopherol in the tissues was affected significantly by dietary α‐tocopheryl acetate content and by dietary fat source. There was a negative correlation between (n‐3) fatty acids and the storage of α‐tocopherol, while this was positively correlated with (n‐6) fatty acids. The content of α‐tocopherol in fish affected the stability during storage with the content of malondiaidehyde used as a parameter for measuring the extent of fat oxidation. Other relationships, e.g. with sensory qualities and S‐containing substances in the edible part of the fish, are discussed.

ISSN:0003-942X    

DOI:10.1080/17450399609381865

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The paper summarises experimental data demonstrating effects of various dietary factors exerting changes in the fatty acid composition and fatty acid metabolism of the common carp(Cyprinus carpioL.). Among the dietary factors (1) supplementary feeding in fish ponds, (2) absence of essential fatty acids (EFA) in the diet, (3) starvation, and (4) ration level were studied.

ISSN:0003-942X    

DOI:10.1080/17450399609381866

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Although carp is in a position to utilize carbohydrates efficiently, lipids are an important energy source in carp diets. In general fat‐enriched high‐energy diets result in rapid growth and favourable feed conversion. Many authors emphasize the protein‐sparing effect of lipid supplementation in carp diets. For efficient protein‐utilization an optimal protein/energy ratio in feed is necessary. Good results may be obtained with diets containing 30–50% high‐quality protein, > 14 MJ digestible energy/kg and a lipid level of at least 15%. Low protein‐high energy diets bring about low nitrogen excretion which is important for maintenance water quality. Lipid‐supplemented diets lead to increased lipid content in the carp. Fingerling carp with high fat deposits exhibit an improved overwintering ability. By using fish oil as lipid source it is possible to produce carp meat with high concentrations of n‐3 polyunsaturated fatty acids which are beneficial for human health.

ISSN:0003-942X    

DOI:10.1080/17450399609381867

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor