Science opens new horizons for marine lipids in human nutrition

Impact of nano-sized plastic on the nutritional value and gut microbiota of whiteleg shrimp Litopenaeus vannamei via dietary exposure

Contamination of the world's oceans with plastic waste has attracted increasing attention in recent years. Whereas the ecological consequences of plastic pollution have been the focus of increasing research, the health-related implications of plastic pollution have been somewhat overlooked. In this study, we exposed whiteleg shrimp (Litopenaeus vannamei), a widely consumed marine species, to nano-sized plastic (polystyrene) via a simulated marine food chain in which mussel (Mytilus edulis) was the food source, and evaluated the effects of plastic contamination on shrimp physical, biochemical, and nutritional characteristics over a 21-day exposure period. We identified the changes in certain important biochemical and nutritional indicators, including changes in the gut microbiota and contents of amino acids and fatty acids. The biochemical analysis revealed that microbial activities in the intestine and the glutathione S-transferase and superoxide dismutase activities changed in L. vannamei exposed to nano-sized plastic. In these individuals, the levels of some essential amino acids and fatty acids also decreased. Overall, our findings indicate that plastic pollution can directly interfere with nutritional changes in marine food resources, thereby indirectly causing potential health implications for human consumers.

Nutritional value of the Tunisian mussel Mytilus galloprovincialis with a special emphasis on lipid quality

This study reports, for the first time, data on nutritional quality parameters in Tunisian mussels, Mytilus galloprovincialis, with an especial emphasis on lipid compounds. Mussel condition index (CI), proximate composition and fatty acid profiles were investigated for a one year period in order to identify the best harvesting period. Analysis revealed that polyunsaturated fatty acids (PUFA) were the dominant fatty acids with a prevalence of n-3 over n-6 forms. Pearson's correlation indicated a strong relationship between CI and PUFA compound and Principal Components Analysis suggested that, from winter to summer, the product maintained a condition sufficiently good for marketing. The best CI and lipid quantity/quality occurred during summer and this may be used as criteria for product labelling. The study also included a thorough literature review that allowed data comparison on mussels from various Mediterranean sites and allowed the mussels from the Bizerte lagoon (North of Tunisia) to be differentiated.

Review: Loss of Quality during the Manufacture of Canned Fish Products

From the moment the fish is caught till it arrives at the consumer as a canned product, raw matter is submitted to a variety of industrial steps. Thus, a storage process (namely, chilling or freezing) is needed for holding the raw material to be canned; a cooking step is normally employed for reducing moisture and inactivating endogenous enzyme activity; a rigorous thermal treatment (sterilization) is undertaken to inactivate micro-organisms; and a proper canned storage is necessary to guarantee good palatability of the product. As a result, labile and essential nutrients (proteins, vitamins, lipids, minerals) present in the raw fish are exposed to different processing conditions that can reduce the nutritional and sensory values of the final product. In the present work, detrimental changes produced in each of the steps involved in the manufacture of canned products are mentioned. This review is focused on nutritional and sensory losses in species commonly employed for canning preparation, and special attention is given to research concerning the effect of varying conditions of previous processing (chilling, freezing and frozen storage and cooking) on the quality of the final canned product. New and current technological strategies are recommended to increase the shelf life of previously stored material and to retain sensory and nutritional quality in the final canned product.

Comparative Analysis of Lipid Content and Fatty Acid Composition of Commercially Important Fish and Shellfish from Sri Lanka and Japan

Sri Lanka is surrounded by the Indian Ocean, allowing plenty of fishes to be caught. Moreover, these fishes represent one of the undocumented fish resources in the world and their detailed lipid profiles have not been previously examined. In this study, the lipid content and fatty acid composition of 50 commercially important fishes from the Indian Ocean (Sri Lanka) and the Pacific Ocean (Japan) were compared. The total lipid content and fatty acid composition, including eicosapentaenoic acid (C20:5n-3, EPA) and docosahexaenoic acid (C22:6n-3, DHA), differed significantly among species. Fish from the Pacific Ocean had higher proportions of fatty acids, including EPA and DHA. Herrings and mackerels from both oceanic areas demonstrated high levels of EPA and DHA, and n-3/n-6 ratio. Brackish and freshwater fishes from both groups showed low levels of PUFAs. Fish from the Indian Ocean were high in n-6 fatty acids. Monounsaturated fatty acid levels were high in omnivorous fish from the Pacific Ocean, and saturated fatty acid levels were high in fish from the Indian Ocean. The results of this study will be of value in determining the dietary usefulness of fish caught in Sri Lanka.

Microbiological and biochemical spoilage of smoke-dried fishes sold in West African open markets

Proximate composition and microbiological characteristics of pre-dried Chrysichthys nigrodigitatus and Pseudotolithus typus were studied over a period of 4weeks to determine the health risks associated with delayed consumption. All analyses were conducted using standard microbiological and chemical methods. Results showed a general decline in microbiological safety and nutritive characteristics of both fish species over time, with an observed increase in microbial loads over time. Aspergillus flavus was also present on both species which makes consumption of the fishes hazardous to the health of consumers due to its ability to produce carcinogenic aflatoxins. In order to minimise the health risks to consumers, it is recommended that smoke-dried fishes be consumed with minimal delay and cooked properly before consumption. The findings of this study will prove important in the development of more stringent regulations regarding food safety in Nigeria.

Effect of ice storage on the functional properties of proteins from a few species of fresh water fish (Indian major carps) with special emphasis on gel forming ability

In the present study the effect of ice storage on physico-chemical and functional properties of proteins from Indian major carps with special emphasis on gel forming ability have been assessed for a period of 22 days. The solubility profile of proteins in high ionic strength buffer and calcium adenosine triphosphatase (ATPase) enzyme activity reduced significantly (p < 0.05), while that of total volatile base nitrogen (TVB-N) increased significantly (p < 0.05) at the end of 22 days of ice storage. The major protein fraction showed association-dissociation-denaturation phenomenon during ice storage as revealed by gel filtration profile and viscosity measurements. The gel forming ability of three fish species both in fresh and during different periods of ice storage was assessed by measuring the gel strength of heat induced gel. Among the three species the gel strength of the gel obtained from Catla catla and Cirrhinus mrigala was higher (586 and 561 g.cm) than the gel obtained from Labeo rohita (395 g.cm) in fresh condition. The gel forming ability of three species was significantly affected (p < 0.05) during ice storage. The TVB-N values of fish meat as a function of ice storage was within the prescribed limit up to 17 days of the ice storage.

Effect of substituting live feed with formulated feed on the reproductive performance and fry survival of Siamese fighting fish, Betta splendens (Regan, 1910)

This study aimed to elucidate the effect of partial or complete replacement of live feed (LF) (Tubifex) with formulated feed (FF) on the reproductive performance of Betta splendens. Three hundred B. splendens fry (average weight 0.19 ± 0.01 g) were equally distributed into five different groups, each with three replicates. They were fed for 105 days with following different diets: control (C)-100% LF; T1-75% LF, 25% FF; T2-50% LF, 50% FF; T3-25% LF, 75% FF, and T4-100% FF. Results showed that the average number of hatched larvae (654 ± 101) and fry survival after 2 weeks of rearing (428 ± 70), after completion of three spawning, were recorded highest in the control group, which was, however, not significantly different from the T1, T2, and T3 groups. At the end of the feeding trial, the highest hatching percentage (90.3%) was registered in the T2 group, which was not significantly different from the control and T1 groups. The T2 group also recorded highest fry survival (65.54%) after completion of three spawning, which was not significantly (P < 0.05) different from the T1 and T3 groups. Control diet contained higher saturated fatty acid (63.23%) than formulated diet (29.80%). In the whole-body tissue, highest level of EPA (0.42%) and DHA (3.13%) were found in the T4 group followed by T3 group. The DHA/EPA ration was recorded highest in the T2 group (10.96%), which did not differ significantly from the T1 and T3 groups. Significant positive correlation was observed between saturated fatty acid levels in fish whole-body tissue and number of hatched larvae (Y = 30.81 × -825.3, R(2) = 0.968) and fry survival after 2 weeks of rearing (Y = 21.38 × -580.9, R(2) = 0.967). Considering all these factors, it can be concluded that the live feed Tubifex can be replaced up to 50% without any adverse effect on the reproductive performance and fry survival of B. splendens.