The aim of the present work was to evaluate the protein value of products from the two seaweeds Saccharina latissima and Palmaria palmata grown in Norwegian waters and to characterize possible beneficial or detrimental effects in the intestine and other organs. Mink, a well-established model for comparison of nutrient digestibility in monogastric animals was used. Two products from each of the seaweeds, a dried whole biomass and a protein concentrate, were evaluated. Five diets were made; a reference diet based on fish meal, and one for each of the four seaweed products. In the latter four, seaweed supplied 200 g/kg of crude protein. Each diet was fed to four male mink for two weeks. The results showed that diets with seaweed were less palatable than the fish meal diet. The animals fed the whole Saccharina diet had a significantly higher water intake and urine production than the other animals, supposedly due to the very high ash content of this seaweed product. This diet also stood out regarding urine concentration of iodine, which was 300 times higher than for the fishmeal-based diet. Apparent digestibility coefficient (ADC) for total amino acids, estimated by difference, showed low values for all the seaweed products; 0.574 and 0.734 for the whole and protein concentrated Saccharina products, and 0.588 and 0.700 for the two Palmaria products, respectively. The apparent amino acid digestibility coefficients (ADC) showed greater variation and were particularly low for histidine, <0.000 and 0.271 for the whole Saccharina and Palmaria products, respectively. Also, the ADC of methionine was low for these products, and cysteine ADC showed negative values for both Saccharina products. The estimated chemical score of the proteins, based on the digestible amino acids profile, was 0 and 520 g/kg for the whole product and protein concentrate of Saccharina, 260 and 520 g/kg for the whole product and the protein concentrate of Palmaria palmata, respectively. Expression of genes associated with digestive and immune functions showed minor effects in the jejunum, somewhat more pronounced effects in the colon. The latter effects were related to immune functions and lipid metabolism. No diet-related alterations in the histology of the jejunum and colon were observed. The histological investigation of liver and kidney structure showed some alterations in the seaweed fed animals. Regarding microbiota assemblage in mucosa of jejunum and colon, no clear diet effects were observed either in richness or diversity. In conclusion: the biological value of the seaweed proteins was low. Only one of the products, the Palmaria protein concentrate, might be considered of any use as a protein source. No clear beneficial or detrimental effects of the seaweed products were observed on gut health and function. The results regarding kidney structure and function, as well as the high iodine in the urine, indicating that further investigations are required to secure that animal health is not challenged by use of these seaweed ingredients in animal diets.
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The nutritional value to abalone of Ulva lactuca L with different tissue nitrogen levels was studied. The seaweed was cultured at two levels of ammonia-N enrichment. Cultures receiving 0.5 g ammonia-N m-2 d-1 ("Iow-N") yielded 164 g m-2 d-1 of fresh thalli containing 12% cmde protein in dry matter and 12 kJ g-l energy; cultures receiving 10 g ammonia-N m-2 d-1 ("high-N") produced 105 g of fresh thalli m~7 d-1 containing 44% protein and 16 kJ g-l energy. High-N and low-N algae and a "standard" mixed diet 005% U. lactuca and 25% Graci/aria conferta (w/w) containing 33% protein and 15 kJ g-l energy were fed to juvenile (0.7-2.1 g) an4 adult (6.9-19.6 g) Haliotis tuberclllata and H. discus hannai in a 16-week feeding trial. Voluntary feed intake of the high-N and slllndard diets were significantly lower than the low-N diet in all the cases. Clear differences in performance between treatments were found in the juvenile and adult abalone of both species. Juveniles fed high-N and standard diets grew significantly faster (specific growtb ratc'of H. tuberculata was 1.03% day-l on high-N algae as compared to 0.72% on low-N algae; H. discus hannai grew 0.63 and 0,3% d\\\\y-l on high-and low-N algae, respectively) and showed much better food conversion ratios. The nutritional value of Ulva lactuca to abalone is greatly improved by a high protein content, attainable by culturing the seaweed with high supply rates of ammonia.
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Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC50 scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo.
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Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC50 scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo.
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Considerable work has been carried out on various aspects of Indian seaweeds. Owing to the utilisation of seaweeds in India for commercial production of agar and algin, the research on seaweeds has attained a new impetus. The assessment of available seaweed resource in India has been necessitated by more and more algin and agar industries coming up in the recent years. Survey of the seaweed resources on the coasts of Tamil Nadu, Goa, Maharashtra, Gujarat and Lakshadweep has been completed and the estimates of standing crop of these areas are available. The seaweed survey of Andhra Pradesh coast has been done recently. The resources survey on the rest of the Indian coastline and of Andaman-Nicobar Islands has to be undertaken to estimate the total standing crop and, in particular, the harvestable quantities of agarophytes and alginophytes.
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Seaweeds constitute one of the commercially important marine living renewable resources. They are used as human food, feed for animals, fertilizer for land crops, source of chemicals and drugs. The estimated total standing crop of seaweeds from intertidal and shallow waters of all maritime states, Lakshadweep and Andaman was 91,339 tons (wet wt.). The quantity of seaweeds estimated in deep waters of Tamilnadu was 75,373 tons (wet wt.) in an area of 1863 sq.km. from Dhanushkodi to Kanyakumari.
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There is a high demand for clean, affordable and sustainable source of energy due to the limitation in fossil fuel supplies. The algae industrial revolutions have proved to be a significant step to realize the growing need for energy and achieving the sustainable development goals (SDGs). In this review, the production and processing of algae from an industry point of view and the algae processing in Industry 4.0 as well as a paradigmatic shift from Industry 4.0 to Industry 5.0 were well-delineated. Moreover, numerous aspects in the algae industry have been discussed, including economic and environmental analysis of algae bioenergy production, customization of the algae-derived bioenergy, algae cultivation and modifications in the cultivating approach. Genetic engineering tools implemented in the algae culture for bioenergy and by-products generation was also studied, and area of focusing such as the desired algae strain and its detection through automated genetic manipulation and genetic modification. Furthermore, the impacts of the Industry 5.0 on the new market opportunities and environment aspect as well as the possibility of achieving SDGs were significantly studied.
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Red seaweeds are the major source of economically important colloids, agar and carrageenan. Agar industry in India shall become commercially attractive only when the yield of agar from the raw material is enhanced. Inherently most Indian agarophytes contain 10-20% agar only. Though species of Gelidiella and Gelldium contain 35-50% agar and the quality of agar in terms of gel strength is also superior, their biomass production is very less, occurrence is seasonal and their exploitation is difficult. Hence an attempt is underway to obtain a hybrid strain of red seaweed for large scale mariculture between slow growing but high agar containing seaweed and fast growing, poor agar yielders. This article enumerates the prospective areas of seaweed biotechnology and its immediate relevance to seaweed mariculture and the related industry in India.
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The use of seaweed as food has been traced back to the fourth century in Japan and the sixth century in China. Today those two countries and the Republic of Korea are the largest consumers of seaweed as food and their requirements provide the basis of an industry that worldwide harvests 6 000 000 tonnes of wet seaweed per annum with a value of around US$ five billion. Increasing demand over the last fifty years outstripped the ability to supply requirements from natural (wild) stocks. Research into the life cycles of these algae has led to the development of cultivation industries that now produce more than 90 percent of the market’s demand....
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Macroalgae (mainly marine macroalgae, i.e. seaweeds) are considered as a very promising source for bioethanol production, because they have high carbohydrate contents, superior productivity, and wide adaptability. Macroalgae are generally grouped into three major categories: red, green, and brown algae. Each category has thousands of species, and each species possesses its unique cellular structure, biochemistry, and constitutes. Converting macroalgae to bioethanol involves pretreatment, saccharification, fermentation, and distillation; and the establishment of economic pretreatment methods is always the first key step for bioethanol production. In present, dilute-acid or alkali hydrolysis is typically used to treat macroalgal biomass. Macroalgae can be depolymerized under mild conditions as they have low lignin content. The resulting polysaccharides can be converted to ethanol through enzymatic hydrolysis, followed by adding bacteria, such as Saccharomyces cerevisiae and recombinant Escherichia coli KO11. Compared with the separate hydrolysis and fermentation process, the simultaneous saccharification and fermentation process often provided higher ethanol titer and conversion efficiency. However, the research on bioethanol production from macroalgae is still in its early stage due to both technical and economic barriers, significant amount of research and development work is needed prior to the commercialization of bioethanol manufacture from macroalgae.
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