Physiological effects of Melaleuca cajuputi extract on Macrobrachium rosenbergii, and its sensitivity against Probopyrus buitendijki.

The effect of Melaleuca cajuputi leaf extract (MCLE) on the biochemical and innate immunity of Macrobrachium rosenbergii was observed during the toxicity test. Thereafter, the sensitivity of MCLE against Probopyrus buitendijki was investigated. Firstly, the MCLE phytochemical compounds were analyzed using gas chromatography-mass spectrometry (GC-MS). Then, the MCLE solution was formulated at 0.00 (control), 0.28, 0.57, and 0.85 g/L, exposed to M. rosenbergii, and their biochemical and immunity responses were recorded after 3 days. The MCLE concentration was prepared based on the LC50 value that had been determined earlier. With the same MCLE concentrations, the sensitivity of MCLE against adult male, female, and larvae P. buitendijki was observed after 1 h of exposure using a scanning electron microscope (SEM). The results revealed the presence of 2-isopropyl-10-methylpenanthrene, phenanthrene, 1-methyl-7-(1-methyl ethyl)-, and 4H-1-benzopyran-4-one, 3-acetyl-5, 7-dihydoxy-2-methyl to be the major compounds in MCLE. A significant elevation (p<0.05) of the total protein (TP), alkaline phosphatase (ALP), and phenol oxidase (PO) activities of M. rosenbergii exposed to MCLE was observed compared to control. The total hemocyte count (THC), granular cells (GC), and hyaline cells (HC) were also increased (p<0.05) in MCLE-treated M. rosenbergii. All adult males, females, and eggs of P. buitendijki were dead after 1 h of exposure. Light damage including size reduction was observed in adult male and female P. buitendijki at 0.28 g/L MCLE, while their eggs were shrunken and some of them ruptured. Severe damage was observed in all adult male and female P. buitendijki at 0.85 g/L MCLE, with dented dorsal surfaces, and all eggs were ruptured. Findings indicated the potential of MCLE to improve immunity and health of M. rosenbergii, as well as act as an anti-parasitic agent against P. buitendijki. [ABSTRACT FROM AUTHOR]