Marine by-products tested as feed for almaco jack Seriola rivoliana and their effect on fatty acids and sterols in different tissues.

Marine by-products can compose up to 70% of the total weight of produce from fisheries; most of these by-products are discarded. However, these by-products are rich in highly unsaturated fatty acids that are not synthetized by most marine animals that are produced by aquaculture. Here, we used three marine by-products (shrimp head, Catarina scallop viscera, and Pen shell viscera) to produce meals without the step used to separate lipids as is traditionally done; this separation can promote hydrolysis of lipids and ultimately, oxidation of fatty acids and sterols. Lipid-rich meals were used to partially substitute commercial fishmeal on feeds that were used to grow almaco jack (Seriola rivoliana) juveniles for 10 weeks. The content of 20:5n-3 and 22:6n-3 in tissues of fish fed shrimp and Pen shell presented values similar to controls, but the former had had a better effect on growth, lipid, and phytosterols levels. However, Catarina meal had lower concentration of 20:4n-6 and 22:6n-3 but higher proportion of 20:4n-6 in muscle and 22:6n-3 in liver, indicating a selective conservation in relation to other fatty acids. Catarina meal contained traces of 18:5n-3 (0.02 g/kg) indicating that these scallops, albeit their healthy aspect, were in contact with toxins (okadaic acid) produced by dinoflagellates, a setback that needs to be addressed previous to meal manufacturing. In conclusion, marine by-products processed to maintain lipid composition can be used to reduce the use of fishmeal in the diet, and their use improve the lipid content and growth compared to control diet with fishmeal.

Phytochemicals from bryophytes: Structures and biological activity

Little attention has been paid to the bryophytes as sources for human diet despite of the presence of 23000 species in the world. Some mosses contain vitamin B1, tocopherols, prostaglandin-like highly unsaturated fatty acids and phenolic compounds. On the other hand, liverworts contain enantiomeric mono-, sesqui- and diterpenoids to those found in vascular plants. Additionally, they possess bibenzyls, bis-bibenzyls and polyketides, many of them showing various bioactivity such as antimicrobial, antiviral, anti-inflammatory, cytotoxicity against cancer cell lines, muscle relaxing, antioxidant and other. In this paper, the structures of phytochemicals from bryophytes and their biological activities will be discussed.

REDUCING CALORIES OF MARGARINS

The goal is to reduce the calorie content of margarines by changing the composition and fat base. In this regard, we studied the change in caloric content and the content of trans-acids in margarines with a change in their fat content. To reduce calorie content, the fat base of margarine was also reduced to 60%, and to increase the biological value of the product, it was enriched with highly unsaturated fatty acids. It was determined that with an increase in the number of unsaturated fatty acids and a decrease in the margarine fat content, the stability of the emulsion deteriorates. To increase the durability of low-calorie margarine emulsions, it is necessary to increase the flow rate of the emulsifier or enrich it with other functional substances.

Characterization, mRNA expression and nutritional regulation of a Δ6 fatty acyl desaturase-like gene by dietary DHA levels of Perinereis aibuhitensis (Gube, 1878)

The Δ6 fatty acyl desaturase (Δ6 Fad) enzyme plays an important role in the pathways for the biosynthesis of the highly unsaturated fatty acids (HUFA) by converting linoleic (LA, 18:2n-6) and α-linolenic (LNA, 18:3n-3) acids to 18:3n-6 and 18:4n-3, respectively. In the present study, a Δ6 Fad-like gene was cloned and its characterisation, tissue expression and nutritional regulation by dietary DHA (docosahexaenoic acid) levels were analysed in the clamworm Perinereis aibuhitensis. The full-length cDNA was 1535 bp including a 1335 bp open reading frame (ORF) encoding a polypeptide of 444 amino acids, a 113 bp 50’-UTR and an 87 bp 3’-UTR with a poly (A) tail. Sequence comparison revealed that the predicted protein shared higher homologies with Δ6 Fad from Apostichopus japonicus with 56% identify. The tissue distribution of P. aibuhitensis Δ6 Fad-like mRNA was found predominantly in intestine, followed by head, esophagus, stomach and other tissues. Quantitative real-time PCR showed that the Δ6 Fad-like transcriptional levels in intestine gradually decreased with increased content of dietary DHA.