Abstract:
Eri silk production and productivity depends highly on feeds consumed by eri silkworms (Samia cynthia ricini B.),
which will be a function of feed sources. Preferred feed of eri silkworms is castor, however, there is an important
difference in feed utilization efficiency when different castor genotypes were used as feed source for this silkworm.
In this experiment, feed utilization efficiency of eri silkworm was studied on eight different castor genotypes namely
Abaro, Acc 106584, Acc 203241, Acc 208624, Ar sel, Bako, Hiruy and local genotypes in Melkassa Agricultural
Research Center, Ethiopia. The treatments were laid out in a Completely Randomized Design (CRD) in three
replications. Fifty worms after their fourth molt were placed on rearing trays provided with castor leaves harvested
from the eight different genotypes. The genotypes caused significantly different feed utilization efficiency on eri
silkworm. Among castor genotypes, Abaro and Acc 208624 expressed better performance in all evaluated variables
simultaneously. These genotypes yielded 6.672 and 6.904 g/larva of ingesta, 3.379 and 3.574 g/larva of digesta,
50.637 and 51.766 % approximate digestibility, 2.026 and 2.073 reference ratio, 0.814 and 0.862 relative
consumption rate, 33.164 and 31.406 % efficiency to convert ingested leaves to larval biomass, 19.811 and 19.236
% efficiency to convert ingested food to cocoon as well as 39.126 and 37.173 % efficiency to convert digested food
to cocoon, respectively. As a result, these castor genotypes were recommended to future research and development
endeavors of integrated eri silkworm farming and castor seed production.
