In Fiji, little or no attention has been given to entomopathogenic nematodes (EPNs) in biocontrol programs due to the lack of awareness about their occurrence and distribution in Fiji. A survey of EPNs was conducted for the first time in Fiji Islands in 2012 and 2013, throughout the eight provinces in Viti Levu to determine the occurrence and distribution across different habitat in Viti Levu. The soil samples from various habitats were collected and assayed for the presence of EPN using Galleria mellonella as baits. EPNs were recovered from five out of seven provinces with 35 positive sites (7.3%) out of 478 sites sampled. The only EPN genera encountered was Heterorhabditis. Steinernema was not isolated from any of the samples. Characterization of isolates was done by using morphometric and molecular examinations and isolates were identified as Heterorhabditis indica. H. indica isolates were primarily recovered from leeward side of the Viti Levu Island along the coastline and riversides, being more prevalent in lighter soil with pH > 6. Further, this study found significant association between habitat type, soil type, soil pH, average annual rainfall and EPN occurrence. This is the first record of naturally occurring EPNs in Fiji. The found nematodes will serve as the basis for efficacy screening with the ultimate aim of delivering effective, more sustainable and environmentally safe control for agricultural pests in Fiji.
Entomopathogenic nematodes (EPNs) in the families Steinernematidae and Heterorhabditidae are obligate parasites of soil inhibiting insects. EPNs are being widely researched as promising biocontrol agents for a wide range of agricultural pests. It is known that strains of EPNs isolated from different geographical regions differ in their attributes, such as host-finding ability, host range, infectivity, reproduction, and environmental stress tolerance. A precise knowledge of these factors is therefore an essential pre-requisite for devising successful strategies to use these nematodes in biological control programmes. Thus, ecological characterisation of the EPN Heterorhabditis indica (Rhabditida: Heterorhabditidae) newly isolated and representing the only species of EPN reported from the island of Viti Levu, Fiji was carried out using Galleria mellonella larvae (L) (Pyralidae: Galleriinae) as hosts to allow comparisons between bioassays conducted in different laboratories around the world. Temperature data showed that native isolates of H. indica are warm-adapted nematodes with thermal range for infectivity between 15˚C and 35˚C and can reproduce between 20˚C and 30˚C. They are highly virulent with LC50 values against G. mellonella ranging from 2.8 IJ to 3.8 IJ/larva. However, they showed poor desiccation tolerance and fail to infect hosts in soil with moisture levels below 8%. They showed a moderate level of hypoxic tolerance and can be stored at 15˚C for 4 months. Results also showed great variability within the selected native isolates of H. indica. Beneficial traits for selected isolates were added up to identify a superior candidate. The current study also suggested that the thermal niche breadth for infection can differ among conspecific strains of an EPN species. The results of this experimental study on ecological aspects of these native isolates of H. indica should form a basis for their potential use in biological control of insect pests in Fiji.
Study was conducted to evaluate the hepatoprotective effects of Seabuckthorn leaf extract (SLE) supplementation on serum enzymatic levels in streptozotocin (STZ) induced diabetes mellitus in Wistar rats. Thirty-two adult male Wistar rats were divided into four groups namely CON (negative control), SCO (Seabuckthorn control), DCO (Diabetic control), and DSL (Diabetic seabuckthorn treatment group). Diabetes mellitus was induced by single intra peritoneal injection of STZ @ 50 mg/kg body weight in DCO and DSL group of rats. SLE was administered orally @ 100mg/kg body weight for 40 days to SCO and DSL groups. CON served as the negative control. Blood samples were collected from experimental animals on zero, 20th, and 40th days of trial to study liver specific serum enzyme profile viz aspartate amino transaminase (AST), alanine amino transaminase (ALT), alkaline phosphatase (ALP) and acid phosphatase (ACP). Significantly (P less than 0.01) higher levels of all the enzymes studied were observed in experimentally induced diabetic rats in comparison to normal rats. However, in SLE treated diabetic rats (DSL group), significant (P less than 0.01) improvement was observed in all the above enzymes. It may be concluded that SLE exerts hepatoprotective effect in STZ induce Diabetes mellitus in Wistar rats.
Aim:To evaluate the protective and ameliorative effect of aqueous sea buckthorn leaf extract (SLE) on hemato-biochemical profile in lead intoxicated Wistar rats.Materials and Methods:An experiment was conducted for 60 days. 36 adult male Wistar rats with a mean body weight of 177.8±12.6 g were divided into five groups and were subjected to various daily oral treatment regimens. Group I served as a negative control receiving only feed and water, Group II (positive control for lead) received lead acetate at 250 ppm in drinking water, and Group III (positive control for SLE) received SLE at 100 mg/kg b.wt. Animals in Group IV received a combination of lead acetate at 250 ppm in drinking water for the first 45 days and SLE at 100 mg/kg b.wt. throughout the experimental period of 60-day, and in Group V for the last 15 days of the trial after the administration of lead acetate until the first 45 days of the trial to study the protective and ameliorating effects of SLE, respectively. Blood samples were collected from retro-orbital fossa of each rat on 0th, 45th, and 60th day of the experiment for hemato-biochemical analysis including hemoglobin (Hb), packed cell volume (PCV), serum total protein, albumin, globulin, albumin:globulin ratio, cholesterol, urea, and creatinine.Results:Significantly (p<0.01) lower levels of serum total proteins and albumin, and a significantly (p<0.01) higher serum cholesterol, urea and creatinine levels were observed in Group II (lead intoxicated group) in comparison to Group I (negative control). Administration of SLE at 100 mg/kg body wt. to lead intoxicated Wistar rats resulted in normalization of almost all the biochemical parameters studied in both the treatment Groups, i.e., IV and V (protective and ameliorative). However, the effects were more pronounced in the protective group. No effects of SLE supplementation were observed on Hb levels. PCV levels improved in protective groups, but no effect was observed in ameliorative group in comparison to lead intoxicated groups.Conclusion:SLE administration at 100 mg/kg b.wt. to lead intoxicated Wistar rats may be used to protect/ameliorate lead induced biochemical alterations in Wistar rats.
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