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White spot syndrome virus (WSSV) is a major pathogen in shrimp culture because of its high infectivity, fast transmission speed, and high fatality rate. White spot disease (WSD), caused by WSSV poses a substantial threat to shrimp production. Therefore, it is crucial to identify effective antiviral agents to mitigate the economic loss caused by WSD. In this study, we prepared 20 ethanol extracts of Chinese herbal medicines (CHMs) and evaluated their anti-WSSV effectiveness using Litopenaeus vannamei larvae as a model. Among the tested extracts, Punica granatum L. exhibited the highest inhibition of WSSV infection at 85%, followed by Gentiana macrophylla at 79% and Isatis tinctoria L. at 63%. Quercetin, an active ingredient found in P. granatum at a concentration of 6.3 μM, increased the survival rate of WSSV-infected larvae by 30% after 72 hpi, and significantly inhibited WSSV infection. Further data from pre-incubation assays indicated that quercetin exhibited a potentially destructive effect on WSSV virions, thereby reducing the virulence and blocking viral horizontal transmission. Moreover, the high stability of the aquacultural water facilitated the continuous exchange of quercetin treatment, which further prolonged the survival time of WSSV-infected shrimp such that the survival rate was still at 13% after 5 days. These results highlight the potential application of quercetin in eliminating WSSV during shrimp larval production. • Pomegranate and quercetin showed anti-WSSV activity in water. • Quercetin blocked horizontal transmission of WSSV virions by reducing its infectivity. • Quercetin was stable in water and had therapeutic effect on WSSV-infected shrimp. [ABSTRACT FROM AUTHOR]

The white spot syndrome virus (WSSV) is rapid onset and high mortality, which has caused a devastating blow to shrimp culture around the world. However, there are no effective measures to prevent and control the WSSV. Thus, it is urgent to find a safe and efficient measures to prevent the outbreak of WSSV. Here, the anti-WSSV activities of 20 Chinese herbal medicine ethanol extracts were evaluated in Litopenaeus vannamei. Among these, the ethanol extract of cinnamon (Cinnamomum cassia Presl) had the highest inhibition rate of 91% on WSSV genome replication. Surprisingly, cinnamaldehyde, the main component of cinnamon extract, has a simple structure and could reduce the copy level of viral genome in shrimp, with the strongest inhibitory effect of 93% at 72 h, and more than 40% of diseased shrimp survived. Further experiments showed that cinnamon extracts and cinnamaldehyde could prolong the cumulative survival time of WSSV-infected larvae, and continuous treatment with cinnamaldehyde could maintain the replication of WSSV genome at a low level. In addition, cinnamon extracts and cinnamaldehyde could significantly inhibit the horizontal transmission of virions at 72 h by 71% and 42%, respectively. Obviously, this further reduces the risk of WSSV outbreak. Similarly, cinnamaldehyde pre-incubated shrimp and virions could improve the tolerance of shrimp to WSSV and reduce the infectivity of virions. Taken together, cinnamon extract and cinnamaldehyde could inhibit WSSV genome replication and reduce mortality rate of WSSV-infected shrimp. The results provided a scientific basis for the use of cinnamon extract and cinnamaldehyde to unlock the outbreak of WSSV, and were worthy of further study and consideration. • Cinnamon ethanol extract and cinnamaldehyde exhibited anti-WSSV activity. • Cinnamaldehyde could reduce the infectivity of WSSV virions and has therapeutic effect on WSSV-infected shrimp. • The structure of cinnamaldehyde is simple and could block the horizontal transmission of WSSV. [ABSTRACT FROM AUTHOR]

White spot syndrome virus (WSSV) is a pathogen that can infect many crustaceans, and that has caused huge economic losses in the shrimp industry. No effective prevention and control measures are currently available. In the present study, the ethanolic extract of Scutellaria baicalensis (SBEE) at 200 mg/L provided >50% protection for WSSV-infected shrimp larvae, and baicalein at 100 μM, one of the main anti-WSSV active substances in S. baicalensis , was 66.7% effective. When shrimp larvae were infected with WSSV after 8 h of SBEE and baicalein preincubation, the respective copy numbers of the viral genome were decreased by 31% and 46% versus the control group. Similarly, WSSV genome copy number reductions of 49% and 55% were observed in WSSV-infected shrimp larvae after 72 h of SBEE and baicalein immersion, respectively. In addition, SBEE or baicalein continuous treatment significantly reduced the viral loads in vivo , effectively blocking the horizontal transmission of WSSV between hosts. SBEE or baicalein also enhanced the expression of Toll4, Dorsal and antimicrobial peptides (AMPs) to restrict WSSV infection. In conclusion, S. baicalensis and baicalein are promising feed additives and immune enhancers for the control of WSSV infection. • Baicalein from Scutellaria baicalensis exhibits an anti-WSSV activity. • Baicalein blocks WSSV transmission in shrimp. • Baicalein enhances the immune resistance of shrimp to WSSV. [ABSTRACT FROM AUTHOR]

Abstract: Understanding the effects of incubation temperature on embryos and hatchlings may have important implications for husbandry and conservation in turtles. Unfortunately, such knowledge is deficient for most Asian turtles. We incubated eggs of the Chinese three-keeled pond turtle (Chinemys reevesii) at 6 constant temperatures (24, 26, 28, 30, 32 and 34 °C) to test for the effects of embryonic thermal environment on incubation duration, hatching success, hatchling size and mass, sex ratio and post-hatching growth. Incubation duration (ID) decreased nonlinearly as the temperature (T) increased, and could be estimated by the equation: ID=42.74⁎exp (4.30/(T −17.28). Eggs incubated at 32 °C and 34 °C had lower hatching success than those at 24 °C, 26 °C and 28 °C. The turtle showed a Male–Female pattern of temperature-dependent sex determination (MF or TSDIa), with male bias at low temperatures (24 °C and 26 °C), and female bias at high temperatures (30 °C, 32 °C, and 34 °C). The relationship between sex ratio (SR) and temperature (T) could be estimated by a nonlinear equation, SR=0.025+0.923/(1+exp (−(T −30.03)/0.009))^0.006. Hatchlings from eggs incubated at 24, 26 and 28 °C were larger and heavier than their counterparts at 30 °C, 32 °C and 34 °C. However, the temperature influence on hatchling size disappeared when the turtles were 3 months old, while most hatchlings from eggs incubated at 34 °C did not survive. After 3 months, female turtles from 30 °C and 32 °C grew faster than did male turtles from 24 °C and 26 °C; females from 28 °C grew significantly faster than males from the same temperature. In contrast, there was no difference in growth rate either within females or within males from different temperatures. The dichotomy of growth rate between turtles from high vs low temperatures are thus largely attributed to between-sex difference rather than temperature effects. Taken together, our results indicate that the temperatures ranging from 28 to 30 °C are most suitable for egg incubation in C. reevesii, because of the high hatchability and post-hatching survival, and the fastest growth of hatchlings in these thermal regimes. Small hatchling turtles may catch up in the subsequent post-hatching growth if provided with a suitable husbandry environment, given that turtle size at hatching is not a determinant of growth in this species. [Copyright &y& Elsevier]