Apricot Algae Stimulates Immunity Against Phosphorescent Disease in Shrimp

Recent research has shown that apricot algae extract has the ability to stimulate immunity and increase survival rate in black tiger shrimp to help shrimp against disease caused by Vibrio harveyi.

Black tiger shrimp ( Penaeus monodon ) is a species of high economic value and is raised in many countries around the world. According to a report of the General Department of Fisheries, as of September 24, 2019, brackish shrimp farming area reached 705,209 ha, of which tiger shrimp farming area is 606,661 ha. The harvested output is 504,413 tons, of which, the production of black tiger shrimp is 181,585 tons. However, in recent years, due to climate change, the process of saline intrusion has led to many black tiger shrimp farming, poor quality seed, and frequent epidemics. Some common diseases in black tiger shrimp such as WSSV, yellowhead disease YHV, disease caused by micro-spores of EHP, acute hepatopancreatic necrosis caused by Vibrio parahaemolyticus , phosphorescent disease caused by V. harveyi. Illuminating disease is found in larvae, postlarvae of black tiger shrimp and damages economic and shrimp farming of many countries in the world.

When recognizing the signs of disease, most farmers use chemicals and antibiotics to treat the disease, unreasonable dosages lead to some strains of resistant bacteria that reduce the effectiveness of use, residues in the environment and Food affects consumers' health.

Supplementing herbal extracts is one of the measures researched by many scientists due to its high biosecurity, both ability to prevent and treat diseases and less impact on the environment and consumers' health.

Currently, the demand for seaweed is very large, they serve as a source of food, fodder, fertilizer and medicinal source (SánchezMachado et al., 2004). In particular, brown seaweed has been identified as a rich source of bioactive materials with many biological activities such as antioxidant, antibacterial, antifungal, anti-coagulant, anti-UV-B radiation, capable of making heals wounds and regenerates cell structure, enhances immunity (Liu et al., 2012). Specifically, fucoidan is a substance extracted from brown seaweed, containing polysaccharides sulfate, can help boost immunity for black tiger shrimp, whiteleg shrimp against white spot disease virus (WSSV), or stem redness caused by micro bacterium V. alginolyticus.

Apricot algae is a species of seaweed, which grows into large dust, brownish yellow or olive brown, is a species of brown algae. In traditional medicine, apricot algae is considered a valuable medicine, widely applied in the fields of medicine, industry and fisheries. Research Tran Trung Giang, 2015 said that the mixture of polysaccharide extracted from brown algae S. microcystum has the ability to stimulate growth, enhance immunity of white shrimp when supplemented with a ratio of 1.0% to feed. . Simultaneously, polysaccharide extracted from brown algae S. microcystum was evaluated as a strong antioxidant (Huynh Truong Giang et al., 2013).

The trial was conducted to assess the effect of a mixture of apricot algae extract ( Sargassum microcystum ) added to the feed for black tiger shrimp ( Penaeus monodon ). Shrimp were fed with a diet supplemented with S. microcystum extract of various algae extracts at different levels (0%, 0.5%, 1%, 2% from apricot extract), fed continuously. in 30 days.

A challenge test for Vibrio harveyi was conducted in a 60 L plastic bucket with 30 shrimp / treatment.

Result

The total number of white blood cells (THC), the number of granulated white blood cells (LGC), the number of seedless white blood cells (HC) and the enzyme PO activity increased significantly in the 1% supplement group. from apricot algae, the highest survival rate (80%) was recorded in the dietary supplement group with a concentration of 1% of algae extract after infection with V. harveyi. At the same time, the feeding of 1% of S. microcystum extract from apricot algae can increase the immune response and resistance to V. harveyi in black tiger shrimp.

Illness disease caused by V. harveyi is a common disease common in both black tiger shrimp and black tiger shrimp. When infected shrimp will stop eating and grow slowly, affecting the productivity of the crop. Therefore, adding apricot extract to shrimp feed to limit disease is essential. New research has introduced a new method by adding only 1% of apricot algae extract to shrimp feeds to stimulate immunity against pathogens.

Source : tepbac