Vol 12, Issue 4, 2019 Online - 2455-3891 Print - 0974-2441 EFFECTS OF DRIED LEAF POWDER OF OCIMUM SANCTUM IN HEXAMITA-INFECTED FISH ANABAS TESTUDINEUS PRADIP MONDAL, NIMAI CHANDRA SAHA* Department of Zoology, University of Burdwan, Burdwan, 713104, India. Email: sahanvcbu@gmail.com Received: 26 January 2019, Revised and Accepted: 26 February 2019 ABSTRACT Objective: The prophylactic and antioxidative role of the dried powdered of Ocimum sanctum (Tulasi) was measured in Hexamita-infected fish Anabas testudineus. Method: Four groups of infected fish were kept in four separate aquariums and the following doses of leaf powder applied (25 mg, 50 mg, and 100 mg/L) for 10 days, and the first group is considered as control and no such treatment is given there. Results: Histopathology showed a remarkable alteration in the structure of liver tissue. Progressive changes observe along with the treatment schedule in hepatic histology and differential count of blood. Results showed that Hexamita infections significantly increased (p<0.05) the oxidative stress in the liver of infected fish. Whereas the treated fish exposed to different doses of powdered leaf of O. sanctum show significantly higher levels of antioxidant enzymes (Catalase, Superoxide dismutase, Glutathione peroxidase) and lower levels of stress marker (Malondialdehyde) than control fish. This treatment caused a rapid skin formation in the scar region. The highest recovery found in 100 mg/L doses of leaf powder, whereas the least recovery found in 25 mg/L group. Conclusion: The findings of the present study may play a key role in aquaculture industry for controlling the death of fish from Hexamita infection. Keywords: Aquaculture, Hexamita, Histopathology, Ocimum sanctum, Oxidative stress. INTRODUCTION The Holy Basil or Ocimum sanctum is a household medicinal plant commonly known as Tulasi, well known for its remarkable action against a wide range of diseases [1]. Activity includes immunomodulatory, antioxidant activity, antibiotic nature, anti-inflammatory, antiulcer, antipyretic, and chemopreventive properties proven by various researches [2-4]. The immunomodulatory effects of O. sanctum have been reported for various animal species [5]. Among a variety of medicinal plant is predominant throughout the world, but O. sanctum holds the designation “queen of the herb” and retained since generation after generation due to the enumerable medicinal value [6]. From ancient time, Indian tradition recommended to plant a Tulasi sapling in each house and it is considered as a natural energizer. Researcher has been identified and purifies various components from this plant and characterizes different biopharmacological and chemical substances. Various reports are available by scientists from the different continents, and from India, since the past few decades to prove the essential versatile beneficial role of this medicinal herb for the humankind as well as benefits of the animals [3]. The most common and dangerous cause of fish disease in fish culture than any other fish parasites is protozoan parasites [7,8]. Some parasites like ciliates are obligatory in nature and utilize skin as a substrate for adherence and cause enormous damage. It becomes fatal on small fish when infections occur in moderate levels because these parasites infection may stop feeding of fish [8]. Hexamita sp. is one of the most common protozoan parasite has been associated with medium to severe mortalities in hatcheries [9,10]. The mode of infection of the organism is still not clearly understood. Reports show that massive numbers of these protozoa cause high mortalities in fish farm fingerlings and it is not always depends on environmental stress factors [11,12]. This flagellate protozoa is generally an intestinal commensal and it becomes pathogenic only when the number of parasites becomes large in number tropical and temperate fish [13]. Reports suggested that flagellate parasites create problems with the nutrition by consuming essential nutrients by disintegrating the epithelium of intestine [14]. Hexamitiasis is one of the most frequent parasitic infections of fish, specifically in juvenile carp and also some aquarium and many marine fish. Infected fish become weak, restless, and anorexic. Head appears large in respect to the body when the infection becomes in great amount. Fish showing loss of balance in highly infected conditions and they swim on each of either side [7,15]. Fish with acute Hexamita infection exhibit higher mortality rate over a very short period of time due to rapid growth of the parasite causes damage to the epithelium. During spring and autumn the chronic form of hexamitiasis generally occurs, resulting higher death rate than non- infected fish [15]. In temperate fish when infection occurred with Hexamita sp. resulting anemia, weight loss, dark body color, intestinal anomaly, excessive mucus secretion, and yellow color mucus secreted from intestine due to addition of bile; in addition, blood also oozing out from infected intestine forms intestinal hemorrhage and hepatic disintegration may also be found [16,13]. Fish with heavily infected condition parasites are profound in the digestive tract, did not show any symptoms of damage to mucosa and without invasion of the parasite into the epithelial tissue [17]. Severe infection by this parasite in fish creates the oxidative stress [18]. However, there is no such information available on fish in this context. Nowadays, the practice has profound to replace the commercially available pharmacy chemical by organic substances which is less toxic and environment friendly. O. sanctum is the most common medicinal and easily available widely used medicinal plant to control different infection. This study is trying to find out the prophylactic quality of dried leaf powdered of O. sanctum and its antioxidative role and recovery. This may be used as a curing measure to defend Hexamita infection and reduce mortality of cultured fish without causing any side effect and environmental problems. © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2019.v12i4.31754 Research Article