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Chemical and fatty acids composition of fish roes
Full text linkThe global crisis of wild caviar production, due to the block of catch quotas granted by the CITES, caused by the steady decline of world sturgeon populations and the limited production from aquaculture, that has not made up for the caviar demand, has allowed the creation of a market for cheap caviar substitutes. Various fish species are used for the production of caviar substitutes, whose eggs shows different characteristics from a nutritional point of view. The aim of present study was to investigate the chemical composition and fatty acid profile of fish roes deriving from seven different species, collected in the Italian market. The survey involved 12 samples of salmon eggs (Oncorhynchus keta), 11 of lumpfish (Cyclopterus lumpus), 3 of rainbow trout (Oncorhynchus mykiss), 3 of pike (Esox lucius), 3 of cod (Gadus morhua), 3 of Alaska pollock (Theragra chalcogramma) and 3 of capelin (Mallotus villosus). The eggs proximate composition (AOAC standard methods) and fatty acid profile (GC analysis) were determined. The data were processed by SPSS 22 statistical package. Salmon eggs (217.3 ±32.7 mg) were the biggest while the smallest resulted the cod eggs (0.16 ±0.08 mg). Generally, eggs of greater size showed the higher protein and lipid content. Protein content ranged from the value of 29.6 ±0.8 g/100g of salmon to the 8.1 ±0.6 of capelin, while lipid content ranged from 12.8±0.6 of salmon to 2.8 ±0.6 of Alaska pollock. With regard to the fatty acid composition, the fish eggs showed some peculiarities. EPA and DHA (their sum ranged from 46.6% of total fatty acid of pollock to the 20.9% of pike) were dominant in all sea species (salmon, capelin, cod, pollock and lumpfish) while pike and trout presented a higher amount of oleic acid (21.6 % and 27.1% respectively). Eggs from trout, the only farmed species, presented also a significant amount of linoleic acid (9.4%) if compared with all the other species. This content probably derived from the vegetable oils utilized in feed formulation. This study contributes to the chemical characterization of caviar substitute present on the Italian market. Salmon eggs showed a chemical composition that was more similar to caviar, according to our previous results obtained from caviar samples coming from four different farmed sturgeon species. Regarding fatty acid profile, fish eggs presented a valuable content of essential fatty acids of the omega-3 series, which were higher if compared to the more expensive caviar
CRYOPRESERVATION OF POULTRY SEMEN - A REVIEW
No full textAlthough still in the experimental phase, the technique of freezing domestic fowl semen may prove of interest and value to the industry. Various stages of the application of this method of preservation still need to be improved. One of the most critical aspects is the choice of cryoprotectant and its use during the process of freezing and thawing. While glycerol has a better cryopreservative action than other cryoprotectants in domestic fowl semen, it exerts a widely demonstrated contraceptive action, the mechanism of which has not yet been clarified. Thus the use of glycerol as a cryoprotectant must be accompanied by its complete removal before insemination.
The fertilizing capacity of semen preserved by freezing is notably less than that of fresh (non-preserved) material and has been evaluated as 1.6% and 19.7%. Genetic influences appear to affect spermatozoan response and tolerance to thermal treatments resulting in differences in subsequent fertility. Most studies using fowl semen report final freezing temperatures between -79-degrees-C and -196-degrees-C, a cooling rate of 1-10-degrees-C/minute and a thawing rate of 50-70-degrees-C/minute.
Straws have been found to be more satisfactory containers than glass vials or ampoules for preserving semen from domestic fowl
Gli OGM in alimentazione animale e garanzie di qualità e sicurezza alimentare per l'uomo dei prodotti derivati : stato dell'arte
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Pangasianodon hypophthalmus haplotype hp 07 cytochrome oxidase subunit I (COI) gene, partial cds; mitochondrial
No full textUse of Spirulina (Arthrospira platensis) as protein source for the nutrition of juvenile tench (Tinca tinca)
Full text linkSpirulina is a protein source that have a high potential in formulation of fish feeding, as tested by several authors. Spirulina, in contrast to other protein terrestrial plant source, such as soybean meal, does not contain anti nutritional or toxic factors. Its composition include several nutrients, like antioxidants, vitamins and essential fatty acids. In our study we tested the growing response of tench to the substitution of fish meal with spirulina meal, focusing also to the variation of fatty acid profile and to the antioxidant proprieties of spirulina, using the formation of DNA adducts 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) as an indicator of oxidatively generated DNA damage.The results of the present trial demonstrated that it is feasible partially to replace fish meal with spirulina meal in the diet of juvenile tench, although the fatty acids profile of fish resulted affected by the presence of Linoleic Acid, introduced by spirulina meal. Spirulina showed in vivo antioxidant capacity, since fish fed with the highest amount of spirulina presented the lowest DNA adduct formation. Spirulina could be a valuable and sustainable source of protein for aqua feed, taking into account the cost of this ingredient, which could decrease in near future
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