Biology Online is a Biology blog and dictionary site that provides up to date articles on the latest developments in biological science. The Biology Online Dictionary is a completely free and open dictionary with over 60,000 biology terms. It uses the wiki concept, so that anyone can make a contribution.
Category: Aquaculture

Nutrients and bioactive potentials of green and red seaweeds

Seaweeds are macroscopic multicellular algae that have been used as food since ancient time. It was originated in Japan and then China particularly to the people who lived near the coastal areas. In addition to its nutritional value, seaweeds are rich source of structurally diverse bioactive compounds including polysaccharides, phlorotannins and pigments. Because of this, the demand  increases in the global trade wherein Korea is the major producers. In traditional Korean cuisines seaweeds used as soup, snack, pickle, vegetable and salad. Hence, this present research focuses on the edible green and red seaweeds found in Korea.

 

Green and Red Seaweeds Bioactive Compounds

Green seaweeds used to treat stomach disorders and hangovers because it contains 55% polysaccharides, 30% proteins, 13% ash and 1% lipids. It also have micro mineral such as calcium, manganese, iron, selenium, sodium, phosphate and potassium. Additionally, green seaweeds also used to treat wastewater and have significant medicinal value for rheumatism, high blood pressure and diabetes. In recent findings it has potentials bioactive properties to treat cancers and diabetes mellitus. Also it contains essentials oil to inhibit foodborne pathogens, anti-inflammatory, antioxidant and blood lipid reduction. Moreover, it has been used in traditional medicine for sunstroke, urinary diseases and hyperlipidemia. It is also useful to reduce eutrophication in mariculture waters that helps the survival rate productivity of shrimps and prawns.

 

Red seaweeds are the main source of hydrocolloids and contain vitamins A, B and C. It is also a rich source of carbohydrates particularly galactose and glucose. These red seaweeds are popularly known in agar production. And used as a raw material in bio-ethanol industry due to its high level of ethanol extraction efficiency. Likewise, both red and green seaweeds contain antioxidants properties due to its hydroxyl radical scavenging activity. That is responsible for neuro-protection against oxidative stress. In all, seaweeds have potential properties for anticancer, anti-diabetic, anti-obesity, anti-inflammatory, antimicrobial and anti-coagulant.

 

Therefore, seaweeds are vital source of food and medicine on different applications. The presences of secondary metabolites are potential to develop as functional materials due to its promising bioactive properties. Korea is one of the biggest consumers and producers wherein people mostly incorporate seaweeds on daily diets. This research suggests that increase consumption offers healthy benefits as well as utilization of seaweed materials as functional ingredients.

 

Source: Prepared by Joan Tura from  BMC Fisheries and Aquatic Sciences

Volume 21:19, 6 April 2018

 

Potential of Insect-Based Diets for Atlantic Salmon

Atlantic salmon, a ray-finned fish that is found in northern Atlantic Ocean and rivers that flow through Atlantic. These are the largest species in their genus ranging from 71cm-76 cm in length. Young salmon spend up to four years in the natal river and slowly move out after into the ocean. It will then change in color from stream adapted gray spots to sea adapted shiny sides. The study aimed to assess the effects of insects and insect oils on the dietary meal of Atlantic reared salmon. Since the global consumption of salmon fish are of highly in demand. So, to meet these growing needs an increased of production efficiency of aquaculture is needed. While maintaining the environmental sustainability, the choice of ingredients on fish diet can greatly influence environmental impacts.

 

Diets of Atlantic Salmon

The growth performance, body composition and nutrient digestibility of Atlantic salmon were assessed. The insect and insect oil produced by black soldier flies were introduced as food diets for 8 weeks. Replacing dietary fish meal with insect proteins reveals significant results on digestibility coefficients of protein, lipids and amino acids. It also shows that inclusion of insect meal diets increased the hepatosomatic index and visceral somatic index of Atlantic salmon. Furthermore, fish feeds with insect did not affect voluntary intake, indicating that no negative effect on palatability of Atlantic salmon.

 

On the other hand fish feed with insect oil from larvae grown on substrate enriched with marine macroalgae grew fast. Compared to the fish fed with insect oil from larvae that grown on media with terrestrial organic waste. Indeed, inclusion of marine brown algae improved nutritional composition of the black soldier flies larvae grown on feeding media. Therefore, marine nutrients are especially beneficial for the growth of marine carnivore fish species.

 

Indeed, the study shows that insect meal and oil from black soldier flies larvae hold great potential as nutrients source. It also demonstrates that there is no adverse effect on growth, feed utilization, digestibility and body composition of Atlantic salmon. Moreover, protein efficiency ratio and whole body crude protein were unaffected by insect meal diets. So, it indicates that insect meal can be utilized efficiently as protein source of Atlantic salmon.

 

Source: Prepared by Joan Tura from the Journal of Aquaculture

Volume 491, 1 April 2018, Pages 72-81