Viral diseases are a serious issue for the shrimp aquaculture industry. White spot syndrome virus (WSSV) has been considered one of the most dangerous pathogens infecting cultured shrimp, causing a mortality rate as high as 100% within 7-10 days of viral infection. So far, several protocols have been applied to protect shrimp against virus attacks, but their protection efficiency is very limited. In this study, for the first time, three melanin-containing feedstuffs (F1, F2, and F3) were formulated and fed to cultured shrimp to investigate the ability of melanin to protect shrimp from WSSV. The obtained results showed that F2 had a protection rate of 64% at day 7 and 62% at day 10 after virus challenge. The protection ability of the feedstuff depended on the amount of melanin consumed by shrimp. Moreover, our results also demonstrated that the transcription level of the VP28 gene, which codes for the VP28 protein, a representative for the presence of WSSV, was significantly decreased in shrimp fed F2. Taken together, our study suggests that melanincontaining diets may be applied in aquaculture to protect shrimp against WSSV infection; further, combined protocols with the simultaneous use of melanin-containing diets and other protectants should be studied and applied to increase the protection efficiency.

Introduction: Aspergillus fumigatus and Candida albicans are the most common pathogenic fungi found in Vietnam. Fungal laryngitis has yet to be thoroughly investigated due to the rarity of the disease. This study aimed to describe the clinical, endoscopic and stroboscopic imaging characteristics among patients with fungal laryngitis. Methods: A cross-sectional study was performed on 48 patients diagnosed with fungal laryngitis at the Endoscopy Department of the National Ear- Nose-Throat Hospital of Vietnam from August 2019 to March 2020. Clinical, endoscopic and stroboscopic imaging characteristics among patients with fungal laryngitis were reported. Results: The rate of fungal laryngitis was higher in men compared to women (men/women ratio: 2.2/1). All patients had dysphonia (100%), while other symptoms included coughing (64.6%) and foreign body sensation (50%). In laryngeal endoscopy, fungal pseudo-membrane was thick with white layer (56.3%) on the vocal cords (100%). In laryngeal stroboscopy, less than half of patients had mucosal wave formation (47.9%). The success rate of fungal culture identification was not high (41.7%), with Aspergillus fumigatus as the main pathogenic fungus (90%). Conclusions: Patients with fungal laryngitis in our setting developed prolonged dysphonia. By using endoscopic imaging and stroboscopic imaging, layers of fungal pseudo-membrane on the vocal cords could be observed and extracted for diagnosis.

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Superroxide dismutase (SOD, EC.1.15.1.1) is the enzyme which dismutates superoxide radicals and plays an important role in protection of living cells against oxidative stress. SOD is also involved in immune response in shrimps. In this study, it was found that the total SOD activity of black tiger shrimp muscular tissues is 10 fold higher than that of the haemolymph, however, the specific activity of SOD in the shrimp haemolymph is 9.2 fold higher than that of muscular tissues. By using active gel electrophoresis, 2 different SOD forms were found in black tiger shrimps (one in muscular tissues and two in haemolymph).Using DE-52 cellulose and Q-Sepharose ion exchange column chromatography, one SOD (SOD1) from black tiger shrimp haemolymph was partially purified, and its purity was 31.2 times higher than that of the starting haemolymph. The SOD1 was shown to have mainly one protein band of approximately 24 kDa on SDS-PAGE. SOD1 was most active at 45oC and pH of 5.5. At a concentration of 5 mM, Mn2+ strongly activated SOD1 (up 200% activity), Ca2+ và Zn2+ could increase approximately 20% activity while Cu2+ inhibited more than 60% ativity of the enzyme.