Effect of Asiatic mangrove plant (Rhizophora mucronata) extract on the growth and virulence of Vibrio harveyi causing bioluminescence disease in Penaeus monodon larviculture.

Abstract

Aim of study: Aim of the study: Vibrio harveyi bacteria are affecting shrimps during grow-out practices. The application of chemicals to control V. harveyi has resulted in antibiotic‐resistance among bacteria. An extract of the leaves of Rhizophora mucronata was tested to control the growth and virulences of V. harveyi. Area of study: This study was conducted in the Crustacean Culture Division of ICAR-CIBA, Chennai city, Tamil Nadu State, India. Material and methods: R. mucronata plants were collected from the Pitchavaram area, and the contents extracted. The resultant extract was prepared and tested against the growth of V. harveyi and its virulence factors. The various functional compounds of R. mucronata were screened and volatile compounds were analyzed.Main results: When R. mucronata extract was treated against V. harveyi (350 µg/mL) an inhibitory zone of 14 ± 0.1 mm was obser ved. At 300 µg/mL, the extract was found to be active in decreasing the luciferase to a maximum of 76 counts per second in 30 days and a similar level of bioluminescence was reduced in 15 days. During, shrimp larviculture a reduction in the cumulative percent of mortality 15.70% (p<0.033) was observed when treated with the extract of R. mucronata.Research highlights: When extract (200 μg/mL) of R. mucronata was tested against V. harveyi during Penaeus monodon larviculture, the V. harveyi counts decreased (p<0.049). Volatile compounds viz, tetramethyl-6,7,8,8a-tetrahydro-5H-naphthalene-1-one (38.63%), squa lene (31.19%), α-amyrin, (7.07%) and β-amyrin (8.75%) were detected. It would be desirable to use crude extracts of R. mucronata during shrimp culture to control V. harveyi. Additional key words: antimicrobials; antagonism; shrimp larviculture; aquaculture .Abbreviations used: CFU (colony-forming unit); CPM (cumulative percent mortality); CPS (counts per second); DMSO (dimethyl sul foxide); EPS (exopolysachharide); FT-IR (Fourier-transform infrared spectroscopy); GC-MS (gas chromatography and mass spectroscopy); IR (reflectance infrared); MIC (minimum inhibitory concentration); PL (postlarvae). PSU (practical salinity unit); SAT (salt aggregation test); VHSA (Vibrio harveyi selective agar)Authors’ contributions: Conceived and designed the experiment: SK and KS. Performed the work: KS, SK, BS, and PEP. Analyzed and interpreted data: KPJ, KS and SK. All authors drafted and approved the final manuscript.Citation: Kannappan, S; Sivakumar, K; Jithendran, KP; Sivamani, B; Praveena, PE (2021). Effect of Asiatic mangrove plant (Rhizopho ra mucronata) extract on the growth and virulence of Vibrio harveyi causing bioluminescence disease in Penaeus monodon larviculture. Spanish Journal of Agricultural Research, Volume 19, Issue 3, e0506. https://doi.org/10.5424/sjar/2021193-17044 Supplementary material (Figs. S1 and S2) accompanies the paper on SJAR’s website