Influence of Sudden Thermal Stresses on Growth Rate and Enzymatic Identification of Bombyx mori L. Larvae

Rehab Taha,Saad I,Eman Hassan

doi:10.21608/eajbsc.2014.16048

Abstract

Article History The purpose of this study is to determine the impact of different thermal stresses for different periods on univoltine Bombyx mori embryos and grown larvae in terms of larval growth rates, effective rate of rearing and the enzymatic proliferation of larval haemolymph. Egg groups was exposed to different temperatures; 0°C for one hour, 0°C for two hours, 40°C for one hour and 40°C for two hours, followed by 2 hours recovery at room temperature in addition to a control group, the same was applied to the grown larvae. Larval haemolymph of tested groups were subjected to enzyme electrophoretic analysis by native polyacrylamide gel electrophoresis (PAGE) for phosphatases and esterases identification. Exposure to sudden thermal stress of 0°C for one hour at larval stage recorded the highest growth rate. The sudden thermal stresses did not significantly affect the effective rate of rearing. However, thermal stresses increased ACPase and ALKPase activities and decreased α and β esterases activities comparing to control. These results suggest applying sudden heat thermal proteins in breeding strategy for inducing robustness in productive breeds.

Highlights

Silkworm is one of the most important animals which produce silk thread in the form of cocoon by consuming mulberry leaves during larval period
Growth rate and effective rate of rearing: Among the egg groups exposed to sudden thermal stresses, the highest performance was recorded for control and egg group exposed to 40°C for one hour as presented in Table (1)
The results revealed that, the highest performance was recorded for 40oC for one hr and 0 oC for one hr for egg and grown larvae, respectively

Summary

Introduction

Silkworm is one of the most important animals which produce silk thread in the form of cocoon by consuming mulberry leaves during larval period. Growth and development of silkworm is greatly influenced by environmental factors such as temperature and relative humidity (Hussain et al, 2011). The development of silkworms depends on its metabolic modulations and physiological adaptability, besides its genetic constitution (Chatterjee et al.,1993) and (Thiagarajan et al, 1993). The silkworms likely adapt to low temperature by different mechanisms involving synthesis of low molecular weight proteins, heat shock proteins and regulation of activities of certain key enzymes which plays crucial roles in insect metabolism (Singh et al, 2013)

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