Effect of plant active compounds on immune response and disease resistance inCirrhina mrigalainfected with fungal fish pathogen,Aphanomyces invadans

Abstract

The antibacterial activity of individual and mixed medicinal plant compounds, azadirachtin (Az), camphor (Ca) and curcumin (Cu), was tested at 100, 200, 300, 400, 500, 600 and 700 ppm (mg L−1) against fungal fish pathogen, Aphanomyces invadans, in vitro. At the lower concentrations between 100 and 300 ppm, the mixture of the tri‐herbal (Az+Ca+Cu) compound yielded a higher (P>0.05) zone of inhibition (ZI) of 7 mm than the positive control; the maximum ZI values (8–15 mm) were realized between 400 and 700 ppm (P<0.05). At the lowest minimum inhibitory concentration (MIC) the tri‐herbal compound (100 ppm) yielded 13 colony‐forming units; hence, this dose can be effectively used at the lowest concentration of 100 mg L−1 to ward off the growth of A. invadans in vitro. In Cirrhina mrigala, intramuscular administration (100 μL) of the selected doses of 100, 400 and 700 ppm (mg L−1) significantly enhanced (P<0.05) the serum lysozyme activity (Ly), production of reactive oxygen species and reactive nitrogen species (RNS or NO) by peripheral blood leucocytes on the 10th, 20th and 30th day. A priori administration of the compound in the fish (100 ppm on 30th day) decreased the percentage mortality when challenged with the pathogen while in the untreated group the mortality increased (P<0.05). This study indicates that intramuscular administration of the tri‐herbal compound Az+Ca+Cu at a concentration of 100 ppm could augment the immune response in C. mrigala against A. invadans.

Protective effect of herbal and probiotics enriched diet on haematological and immunity status of Oplegnathus fasciatus (Temminck & Schlegel) against Edwardsiella tarda

“…The decreasing trend in RBC, Ht, and Hb levels in infected fish indicate that RBCs are being destroyed by the leucocytosis activity in erythrocytic anemia with subsequent erythroblastosis [43]. Recently, the restoration of altered haematological parameters by bacterial and fungal infection and their restoration after administration of herbal diet has been documented [15,44]. In our experiments administration of probiotics and mixed diets in infected fish, increased the Ht level significantly (P < 0.05) on week 3 and 6.…”

“…One such way is to augment the level of resistance to infection in the cultured organisms by the use of improved feeds, new vaccines, and immunostimulants [13]. Recently, pharmaceutical preparations of medicinal plants either as pure compounds or as extracts have been widely used against a variety of fish pathogens [14,15].…”

The use of medicinal plants as immunostimulants in aquaculture: A review

“…Intramuscular administration is not commonly used for herbal medicine. Intramuscular administration of the triherbal compound azadirachtin, camphor and augment the immune response in Cirrhina mrigala against the fungal fish pathogen Aphanomyces invadans (Harikrishnan et al, 2009b). In addition, immersing newly hatched offspring of Cichlasoma nigrofasciatum once weekly for 2 months in Tribulus terrestris extract was most effective in terms of masculinization, resulting in a maximum male ratio of 87.23% (Çek et al, 2007).…”

“…They can even be used to treat specific diseases caused by virus, parasites and fungi. Several compounds extracted from medicinal plants inhibited the growth of Gram-positive and Gram-negative organisms (Harikrishnan et al, 2009b). Indian almond extract was an alternative antibacterial remedy against tilapia ecto-parasites and the bacterial pathogen A. hydrophila (Chitmanat et al, 2005).…”

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“…Gannam and Schrock (1999) reviewed various immunostimulants and methods of their application in fish culture. While the effectiveness of different immunostimulants in protecting cultured species against diseases has been extensively researched, such studies with eco-friendly herbal immunomodulators are limited (Venkatalakshmi and Michael, 2001;Dügenci et al, 2003;Jian and Wu, 2003;Rao et al, 2006;Christybapita et al, 2007;Divyagnaneswari et al, 2007;Ji et al, 2007;Sahu et al, 2007;Harikrishnan et al, 2009;Pratheepa et al, 2010 components of the immune system as well as nonspecific immunity with consequent increase in the host defence against pathogenic stimuli. Two dosages (1.5 and 3.0%) of ImmuPlus were tested through dietary administration.…”