In-vivo effect of medicinal botanicals on rearing parameters of the silkworm, PMxCSR 2

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1 In-vivo effect of medicinal botanicals on rearing parameters of the silkworm, PMxCSR 2 S. Saritha Kumari, R. N. Bhaskar* and S. Latha Department of Sericulture, UAS, GKVK, Bangalore 65, Karnataka, India *College of Sericulture, UAS (B), Chintamani , Karnataka, India rn_bhaskar@rediffmail.com & sariseri@gmail.com ABSTRACT Administration of mulberry leaves treated with aqueous leaf extracts of Adhatoda vasica, Phyllanthus niruri and Terminalia arjuna to first instar larvae of PMxCSR 2 hybrid resulted in positive response with respect to rearing parameters. Highest larval weight in all instars viz., first (0.062 g/10), second (0.221 g/10), third (1.18g/10), fourth (4.93g/10) and fifth (29.56g/10) instar, high silk productivity (3.94cg/day), increased filament length (912.50m) and reduced denier (2.41) was noticed in P. niruri administered lots followed by A. vasica and T. arjuna which were next best in the order of merit as compared to control (0.024, 0.101, 1.00, 4.24, 28.98g/ 10 larvae; 3.54cg/day, m & 2.41, respectively). KEYWORDS: Botanical extracts, denier, filament length, larval weight, PMxCSR 2 INTRODUCTION The silkworm, Bombyx mori L. is a monophagous insect feeding on mulberry leaves. Information on nutritional ecology of insects is a pre-requisite for a better knowledge of their ethobiology and physiology. The quality of leaves provided to the worms for feeding has been considered as the prime factor governing the production of good cocoon crop. The leaves of superior quality enhance the chances of good cocoon crop (Ravikumar, 1988). Adequate feed is required to rear silkworm and treatment with leaf extracts of certain plants to the mulberry can increase the silk production leading to economic gains. Further topical administration of Tridax procumbens, Parthenium histerophorus and Tribulus terrestris had increased the larval weight, ERR, silk productivity and cocoon parameters of silkworm, Bombyx mori. (Murugesh and Bhaskar, 2007). Administration of botanicals to silkworm help in supplementation of various biochemical constituents (Amino acid, proteins, alkaloids, glucoside, phyllanthine, psoralen, betasitosterol) which have the property of phagostimulants and attractants was reported in mulberry (Manoharan, 1996). Leaf extracts of Adhatoda vasica, Phyllanthus niruri and Psorealia coryeliafolia when administered to silkworm, exhibited phagostimulant activity and antifungal properties (Prajapathi et al., 2003). It was further confirmed by Shivaprakasam et al. (1998). Hence, Adhatoda vasica (Acanthaceae), Phyllanthus niruri (Euphorbiaceae) and Terminalia arjuna (Combrataceae) were selected for the present study to evaluate the effect of their aqueous leaf extracts on rearing parameters viz., larval and cocoon parameters of the silkworm, Bombyx mori when administered orally through feed. 40

2 MATERIALS AND METHODS Treatment details: The experiment was conducted at Dept. of Sericulture UAS GKVK Bangalore. Geographically, the place is located at latitude North and longitude East. The centre is at an altitude of 930 meters above sea level. The annual rainfall ranges from mm to mm. The mean normal (779.7 mm) and actual annual rainfall (593.3 mm) of the zone for the year. T1 T2 T3 T4 : Adathoda vasica (Stock) : Phyllanthus niruri (Stock) : Terminalia arjuna (Stock) : Control The tender leaves of three botanicals viz., Adhatoda vasica, Phyllanthus niruri and Terminalia arjuna were collected from Sanjeevini Vatika, Department of Horticulture, University of Agricultural Sciences, Bangalore. The required quantity of fresh leaves from each plant was harvested washed with water and surface sterilized with 70 per cent ethyl alcohol followed by washing with sterile water. Then one gram of leaves was macerated with 10 ml of distilled water using Mortar and Pestle, separately for each medicinal plant. The extract was filtered by double layer sterile muslin cloth, later by Whatman s filter paper. The extracts were collected and used as stock solution. Mulberry leaves were washed in running water and sterilized by using cotton swab dipped in 70 per cent alcohol. The sterilized leaves were shade dried for five minutes, then 0.5 ml of botanical extract was smeared on mulberry leaves on both the sides and fed to first instar silkworm (PMxCSR 2 ) as the first feed. The remaining feeds were normal without any botanical treatment. The control (without spraying) was also maintained. The observations were recorded on larval weight, silk productivity, filament length and denier. The first instar larvae was administered with plant extracts and its effect on larval weight was observed in all instars till it reaches final instar. The data was subjected to ANOVA analysis (Sundar Raj et al., 1972) for further interpretations. Design Simple CRD Number of treatments : 4 Number of botanicals : 3 Botanical proportion : 1(Stock) Number of replications per treatment Number of worms per replication Silkworm Hybrid RESULTS AND DISCUSSION Larval weight : 3 : 50 : PMxCSR2 The beneficial effect of plant extracts was assessed based on increase in the larval weight from first to last instar. Among the botanical extracts tested, the stock solution fed lots of P. niruri registered higher larval weight (0.062, 0.221, 1.18, 4.93 and 29.56g/10) of first, second, third, fourth and fifth instar of first instar administered lots and lower weight was encountered with T. arjuna followed by control. This might be due to the enhancement of bio-availability of nutrients for digestion by these plant extracts resulting in robust growth of the silkworm (Table 1). 41

3 Silk productivity (cg/day) Extrafoliation of different plant extracts registered significant results with respect to silk productivity. However, highest silk productivity was recorded in P. niruri treated lots (3.94cg/day) followed by A. vasica (3.84cg/day) and T. arjuna (3.57cg/day). The lowest silk productivity was recorded in control (3.54 cg/day) (Table 2). Filament length (m) The application of different plant extracts to larvae of PMxCSR 2 through mulberry leaves exhibited significant differences with respect to single cocoon filament length. P. niruri registered longest filament length of m followed by A. vasica (898.93m) and T. arjuna (887.97m) and shortest was registered in control (874.95m) (Table 2). Denier Significant differences were seen with respect to denier among the different plant extracts studied. Denier was found higher in T. arjuna and control which were on par with each other (2.41). Whereas, the lowest denier was recorded in P. niruri (2.31) followed by A. vasica (2.36) (Table 2). The results obtained by Murugesh (2002) revealed that aqueous extracts of Tridax procumbens, Tribulus terrestris and Parthenium hysterophorous treated to silkworm resulted in maximum larval weight (33.75, and 30.25g/10) compared to control (30.70g/10). Patil et al. (1997) also recorded similar observations. However, maximum larval weight of 33.80g/10 larvae was recorded in extrafoliation done with 20 per cent P. hysterophorus aqueous leaf extract compared to only 24.47g/10 larvae in water control. Murugan et al. (1999) also observed that, supply of aqueous leaf extract of T. procumbens increased larval weight of 4.15g compared to control. Similarly, administration of mulberry leaves fortified with extracts of Withania somnifera, Tinospora cordifolia and Terminalia arjuna to silkworms, resulted in increased larval weight compared to control (Sridevi, 2003). Gayathri (2005) also evidenced that larval weight was significantly higher in Euphorbia prostrata (3.286g) and Centella asiatica (3.284g) as compared to water (3.248g) and normal control (3.255g). Murari et al. (2008) indicated that, when silkworm hybrid (PMxCSR 2 ) reared on mulberry leaves sprayed with Cucumis sativus exhibited significant difference with respect to larval weight (2.94g) compared to other treatments. The present study on the effect of medicinal plant extracts clearly indicated that, the P. niruri administered lots of first instar PMxCSR 2 worms showed highest silk productivity (3.94cg/day) with longest filament length (912.51m) and improved filament denier (2.31) and was followed by other two botanicals viz., A. vasica and T. arjuna were in order of merit. However, lowest silk productivity (3.54), shortest filament length (874.95m) and highest filament denier (2.41) was observed in control lots. Increase in the silk productivity might be due to presence of biochemical components which stimulate feeding in silkworm resulting in enhanced biochemical processes of protein synthesis which in turn resulted in the higher silk productivity. The current results are in agreement with those of Mamadapur (1994) that the application of 5 per cent dust of Clerodendron inermae to fifth instar larvae increased the silk filament length (683 to 719m), while denier was brought down from 3.65 to Effect of aqueous extract of leaves of T. terrestris and P. niruri showed maximum filament length when compared to untreated worms (Murugan et al., 1994). Extrafoliation of mulberry leaf with 20 per cent leaf water extract of P. hysterophorous resulted in longer silk filament length (873.12m) and reduced denier (2.30) as compared to control (Patil et al., 1997). Similarly, higher silk filament length and superior denier was recorded in the larvae 42

4 dusted with Lantana camara and C. inermae (Santhoskumar, 1997). Further, Murugan et al. (1999) also recorded, the increased filament length from 480 (control) to 902m and 948m when sprayed with C. spaciflorus and T. procumbent, respectively. Murugesh (2002) observed improvement in silk productivity, filament length and denier due to spraying of T. procumbens, T. terrestris and P. hysterophorous at 0.4 per cent concentration. Sridevi (2003) reported that, administration of mulberry leaves fortified with W. somnifera, T. arjuna and T. cordifolia to silkworm recorded highest silk filament length and finer denier compared to control. Similar results were also observed by Gayathri, 2005, Shubha, 2007, Maribashetty et al., 2008 and Murari et al., CONCLUSION Perusal of experiment revealed that administration of aqueous leaf extracts of Phyllanthus niruri through mulberry leaves to first instar larvae of PMxCSR 2 hybrid showed increased larval weight from first to fifth instar, high silk productivity, increased filament length and reduced denier followed by Adhatoda vasica and Terminalia arjuna. The same was found least in control lots. Table 1: Effect of botanical extracts on larval weight (g/10 larvae) of PMxCSR 2 Botanical extracts Larval Weight (g/10 larvae) I II III IV V Adhatoda vasica Phyllanthus niruri Terminalia arjuna Control F test * * * * * SEm± CD at 5% * Significant at 5% Table 2: Effect of botanical extracts on cocoon parameters of PMxCSR 2 Silk productivity Filament Botanical extracts Denier (cg/day) length (m) Adhatoda vasica Phyllanthus niruri Terminalia arjuna Control F test * * * SEm± CD at 5% * : Significant at 5% 43

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