Vol. 10, Special Issue 10 (2021)

Author(s):
Thangamalar Alagesan, Subramanian S, Priyadharshini Pachiappan and Prabhu S

Abstract:
Silkworm is one of the best commercial and beneficial insect in the invertebrates which produce cocoons that act as a source for textile industry in silk and fabric production. In this studies, silkworm nutritional growth indices for two bivoltine pure silkworm races (CSR2, CSR4), bivoltine hybrid (CSR2 X CSR4) and cross hybrid (PM X CSR2) with respect to immunity response against Kanamycin resistant Escherichia coli were studied in third, fourth and fifth instar. The immunity response measured in terms of growth indices viz., food consumption index, digestibility, conversion of ingested food, efficiency of conversion of digested food, silkworm growth rate were analyzed. The results revealed that growth rate of the larvae was affected significantly in CSR2 x CSR4 and PM x CSR2 (0.289 and 0.325) but not in pure races CSR2 and CSR4 (0.300 and 0.303). Approximate digestibility values showed significant difference between control and immunized larvae in the crossbreeds / hybrids, PM x CSR2 and CSR2 x CSR4 (82.857 and 84.064) but not in the pure races CSR2 and CSR4 (84.235 and 83.854). ECI was significantly influenced by immunization, as there was distinct difference between control and immunized set in all the breeds evaluated. ECD values also reflected similar trend depicting the strong negative influence of immunization on this nutritional index. Hence, immunity varies among the different age group of the insect and also the different race.