Comparative biochemical studies of carotenoids in catfishes

Effects of the use of synthetic astaxanthin in the feeding of Lophiosilurus alexandri, a neotropical siluriform fish

Aiming to test the capacity of retention of carotenoids in tissues, Lophiosilurus alexandri juveniles were fed diets containing 0, 25, 50, 100, 200, and 400 mg/kg of synthetic astaxanthin for 62 days. The inclusion of astaxanthin did not result in significant differences in growth, weight gain, apparent feed conversion, and feed efficiency of the fish. Blood biochemistry and liver histology did not change with the different treatments. At the level of 100 mg/kg of inclusion, there were the highest levels of carotenoids in the blood, and muscle and the smallest difference between the muscle x integument ratio.

De novo assembly transcriptome analysis reveals the genes associated with body color formation in the freshwater ornamental shrimps Neocaridina denticulate sinensis

The body color of Neocaridina denticulate sinensis is a compelling phenotypic trait, in which a cascade of carotenoid metabolic processes plays an important role. The study was conducted to compare the transcriptome of cephalothoraxes among three pigmentation phenotypes (red, blue, and chocolate) of N. denticulate sinensis. The purpose of this study was to explore the candidate genes associated with different colors of N. denticulate sinensis. Nine cDNA libraries in three groups were constructed from the cephalothoraxes of shrimps. After assembly, 75022 unigenes were obtained in total with an average length of 1026 bp and N50 length of 1876 bp. There were 45977, 25284, 23605, 21913 unigenes annotated in the Nr, Swissprot, KOG, and KEGG databases, respectively. Differential expression analysis revealed that there were 829, 554, and 3194 differentially expressed genes (DEGs) in RD vs BL, RD vs CH, and BL vs CH, respectively. These DEGs may play roles in the absorption, transport, and metabolism of carotenoids. We also emphasized that electron transfer across the inner mitochondrial membrane (IMM) was a key process in pigment metabolism. In addition, a total of 6328 simple sequence repeats (SSRs) were also detected in N. denticulate sinensis. The results laid a solid foundation for further research on the molecular mechanism of integument pigmentation in the crustacean and contributed to developing more attractive aquatic animals.

A comprehensive review on carotenoids in foods and feeds: status quo, applications, patents, and research needs

Carotenoids are isoprenoids widely distributed in foods that have been always part of the diet of humans. Unlike the other so-called food bioactives, some carotenoids can be converted into retinoids exhibiting vitamin A activity, which is essential for humans. Furthermore, they are much more versatile as they are relevant in foods not only as sources of vitamin A, but also as natural pigments, antioxidants, and health-promoting compounds. Lately, they are also attracting interest in the context of nutricosmetics, as they have been shown to provide cosmetic benefits when ingested in appropriate amounts. In this work, resulting from the collaborative work of participants of the COST Action European network to advance carotenoid research and applications in agro-food and health (EUROCAROTEN, www.eurocaroten.eu, https://www.cost.eu/actions/CA15136/#tabs|Name:overview) research on carotenoids in foods and feeds is thoroughly reviewed covering aspects such as analysis, carotenoid food sources, carotenoid databases, effect of processing and storage conditions, new trends in carotenoid extraction, daily intakes, use as human, and feed additives are addressed. Furthermore, classical and recent patents regarding the obtaining and formulation of carotenoids for several purposes are pinpointed and briefly discussed. Lastly, emerging research lines as well as research needs are highlighted.

Carotenoid Metabolism in Aquatic Animals

Aquatic animals contain various carotenoids that exhibit structural diversity. These carotenoids originate from algae or partly from some bacteria. Herbivorous animals directly ingest carotenoids from dietary algae and metabolize them. Carnivorous animals ingest carotenoids from dietary herbivorous animals and metabolize them. Therefore, carotenoids found in these animals reflect the food chain as well as the metabolic pathways. Carotenoids in aquatic animals are described from the viewpoints of natural product chemistry, metabolism, food chain, and chemosystematics.

Stereoselective synthesis by olefin metathesis and characterization of η-carotene (7,8,7',8'-tetrahydro-β,β-carotene)

The purported structure of the elusive η-carotene (7,8,7',8'-tetrahydro-β,β-carotene), a natural C(40) carotenoid first detected in the berries of Lonicera japonica and in citrus fruits sixty years ago, has been synthesized by olefin cross-metathesis/dimerization of a C(21) polyene derived from trans-7,8-dihydroretinal, thus allowing the full characterization of this highly unstable natural product.

Carotenoids in marine animals

Marine animals contain various carotenoids that show structural diversity. These marine animals accumulate carotenoids from foods such as algae and other animals and modify them through metabolic reactions. Many of the carotenoids present in marine animals are metabolites of β-carotene, fucoxanthin, peridinin, diatoxanthin, alloxanthin, and astaxanthin, etc. Carotenoids found in these animals provide the food chain as well as metabolic pathways. In the present review, I will describe marine animal carotenoids from natural product chemistry, metabolism, food chain, and chemosystematic viewpoints, and also describe new structural carotenoids isolated from marine animals over the last decade.

Astaxanthin binding to solubilized muscle proteins of Atlantic salmon (Salmo salar L.), haddock (Melanogrammus aeglefinus L.) and Atlantic halibut (Hippoglossus hippoglossus L.)

A study was conducted to compare astaxanthin binding ability of solubilized muscle proteins of Atlantic salmon (Salmo salar L.), haddock (Melanogrammus aeglefinus L.) and Atlantic halibut (Hippoglossus hippoglossus L.). Muscle proteins of juvenile Atlantic salmon, haddock and halibut were solubilized by sequential extraction of muscle tissue using low ionic strength solutions. Electrophoretic protein profiles of the six solubilized fractions from these species were similar. Each solubilized fraction from the three species was examined for its relative astaxanthin binding capacity. The amount of bound astaxanthin was significantly different (P<0.05) among the six fractions of each species. Significant differences in astaxanthin binding were only found for fractions A and E among the species. The amount of bound astaxanthin in various fractions of each species showed a good correlation (R2=0.80-0.92) with the ANS (8-anilino-1-naphthalenesulfonate) fluorescence intensity of those fractions. The pattern and extent of astaxanthin binding to the muscle proteins of juvenile salmon, haddock and halibut is comparable to that reported previously for adult Atlantic salmon (Saha, M.R., Ross, N.W., Gill, T.A., Olsen, R.E., Lall, S.P., 2005. Development of a method to assess binding of astaxanthin to Atlantic salmon S. salar L. muscle proteins. Aquacult. Res. 36, 336-343.). These combined observations suggest that the carotenoid binding capacity of the muscle proteins of salmon is not the limiting factor in the deposition of carotenoid in their flesh.