Food consumption and conversion efficiency of eri silkworm Samia ricini Donovan were studied during 4th and 5th larval instars by feeding castor leaves fortified with 100, 200, 300, 400 and 500 ppm concentrations of aqueous extracts of cyanobacteria Anabaena variabilis. The nutritional indices viz., ingesta, digesta, approximate digestibility (%), reference ratio and efficiency parameters like ECI and ECD were recorded which were significantly high at 400 ppm concentration treated batches of 4th instar larvae over control batches. The decline in nutritional efficiency parameters of 5th instar treated larvae might be due to higher utilization of the digested food for metabolic activities. Significant difference of ECI to cocoon % and non-significant difference of ECD to cocoon% and shell were observed between the treatments and control. Cyanabacteria feed supplement contains antibiotic and nutritions factors which has reflective effect on the biological parameters in eri silkworm and therefore has greater application in commercial eri silkworm rearing.
Sericulture has been a traditional rural industry and instrumental in poverty alleviation in India. Qualitative and quantitative increase of cocoon production would certainly result into better economics for this industry and meet production needs. In order to increase the cocoon production, enrichment of mulberry leaves by supplementary compounds is an absolute important aspect (Etebari
Probiotics are the live microbial feed supplements which beneficially affect the host by improving the microbial balance (Yeung
Cyanobacteria (Blue green algae) are free living photosynthetic, and N2 fixing bacteria found in fresh, marine water and terrestrial environments. Genus
Eri silkworm
Cyanobacteria,
Tray-cum shelf rearing method with 25 eri silkworm disease free layings (DFLs) were carried out on castor leaves as suggested by Jayaprakash
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Consumption and utilization studies:
Feed utilization studies were confined to 4th and 5th instar eri silkworm larvae as 80% of total leaves was consumed in these instars. Since resumption to 4th instar, 60 larvae each in four replications (irrespective of sex) of a treatment were maintained separately from general rearing.
Aqueous solution of
The nutritional indices viz., ingesta, digesta, approximate digestibility (AD%), reference ratio (PR) and nutritional efficiency parameters viz., efficiency of converting the ingesta (ECI) and digesta (ECD) into larva, cocoon and shell weight were calculated. Besides, relative consumption and growth rates (RCR & RGR) were computed. The methods of calculation of various parameters (Mathur
The experiments were repeated twice during summer and rainy seasons of 2013 year and pooled data were tabulated, compiled and analyzed by using ANOVA (Analysis of Variance) test.
The food consumption, utilization efficiencies and growth rates of 4th and 5th instars are presented in Table 1 and 2, respectively. The amount of ingesta and digesta varied significantly in 4th and 5th instar larvae fed with castor, R.
Food intake and utilization budget of S. ricini during fourth instar larvae fed on castor leaves fortified with A.variabilis
Food intake and utilization budget of S. ricini during fifth instar larvae fed on castor leaves fortified with A.variabilis
Sampath
The approximate digestibility (AD) defines the quantity of food that was actually digested. AD gradually increased in the treated batches 1 to 4th instar when compared to 5th instar larvae during summer and rainy seasons. significant difference of AD% between control and other treatments batches was noticed (Table 1 &2). This is probably dur to feeding of larvae on supplemented nutrients along with castor leaves. The digestibility is affected by high content of crued fiber deficiency of nutriunts and water in food (Waldbauer, 1964). Similar results of AD as per the age of worms were also reported by Poonia (1978) and Rana
Reference ratio (RR) expresses ingesta required per unit excreta production. High value of RR indicates high rate of digestion and absorption of food. It also expresses the retention efficiency of food. comparatively higher RR (Table 1) was recorded in 400 ppm (T4) treatment(2.47)(2.38) batches than control (1.61) and (1.60) batches of 4th instar larvae recpectively during the both seasons. It indicates that 4th instar larva has to ingest more to produce one gram of excreta. Gokulamma and Reddy (2005) reported that RR and AD (%) values were high during early instars and reduced with advancement of instars of
Efficiency conversion of ingested food (ECI) is an overall measure of the ability of larvae to utilize the undigested food. The ECI recorded was high in 4th instar and lowest in the 5th instar of treated lots. Fourth instar larvae of treated lots performed better with respect to efficiency of conversion of digested food (ECD) recording 82.23 and 80.10% during summer and rainy seasons followed by 5th instar (58.67 and 61.30%) at 400 ppm concentrations. The higher ECD values might be due to higher absorption ability and associated with higher digestibility. The low ECD in the last instar is due to higher utilization of the digested food for metabolic activities. Our findings are in the confirmity with those of Rana
There was consistent increase in the efficiency of conversion of ingested (ECI) and digested (ECD) food into the body substance in 4th instar when compared to decline of both efficiencies in 5th instar. This decline might be associated with energy consuming physiological activities associated with the approach of larval maturity. Similar patterns were also observed by Rana
Relative consumption rate (RCR) and Relative growth rate (RGR) of 4th (1.892 and 0.925) and 5th (2.010 and 0.911) instar larvae were comparatively higher at 400 ppm (T4) of
The efficiency of conversion of ingesta and digesta to cocoon and shell are given in Table 3. Significant difference of ECI to cocoon% was observed between different treatments and control. Higher ECD to cocoon % was recorded in T4 (37.80% in rainy and 35.53% in summer season) and was found non-significant. No Significant difference of ECI and ECD to shell % was observed between all the treatments especially at 400 ppm in comparison to control (Table 3). Maachi and Katagiri (1991) inferred that ECI to cocoon % and shell % were ultimate nutritional indices in terms of productivity to evaluate the production efficiency of breed or hybrid castor leaves supplemented with aqueous extracts of “Spirulina” (Jayaprakash
[Table 3.] Conversion Efficiency Parameters to Cocoon and Shell
Conversion Efficiency Parameters to Cocoon and Shell
This seems to be the first report on consumption and utilization of cyanobacteria,
It can be assumed that the presence of antibiotic and nutritional factors viz., lipids, proteins, vitamins and secondary metabolites in cyano bacteria