Nutrigenetic screening strains of the mulberry silkworm, Bombyx mori, for nutritional efficiency

Chinnaswamy Ramesha1a*, Hothur Lakshmi2b, Savarapu S. Kumari3c, Chebba M. Anuradha4d, and Chitta S. Kumar5e

1Silkworm Breeding and Molecular Genetics Laboratory, Andhra Pradesh State Sericulture Research and Development Institute, Kirikera-515 211, Hindupur, AP, India
2Silkworm Genetics and Breeding Laboratory, Central Sericultural Research and Training Institute, Central Silk Board, Berhmpore, 742 101, West Bengal, India
3Biology Division, Indian Institute of Chemical Technology, Tarnaka, Hyderabad - 500 007, AP, India
4Department of Biotechnology, College of Engineering and Technology, Sri Krishnadevaraya University, Anantapur- 515 003, AP, India
5Bioinformatics Centre, Department of Biochemistry, Sri Krishnadevaraya University Anantapur-515 003, AP, India

Abstract

The activity of sericulture is declining due the reduction of mulberry production area in sericulture practicing countries lead to adverse effects on silkworm rearing and cocoon production. Screening for nutrigenetic traits in silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) is an essential prerequisite for better understanding and development of nutritionally efficient breeds/hybrids, which show less food consumption with higher efficiency conversion. The aim of this study was to identify nutritionally efficient polyvoltine silkworm strains using the germplasm breeds RMW2, RMW3, RMW4, RMG3, RMG1, RMG4, RMG5, RMG6 and APM1 as the control. The 1st day of 5th stage silkworm larvae of polyvoltine strains were subjected to standard gravimetric analysis until spinning for three consecutive generations covering three different seasons on 19 nutrigenetic traits. Highly significant (p ≤ 0.001) differences were found among all nutrigenetic traits of polyvoltine silkworm strains in the experimental groups. The nutritionally efficient polvoltine silkworm strains were resulted by utilizing nutrition consumption index and efficiency of conversion of ingesta/cocoon traits as the index. Higher nutritional efficiency conversions were found in the polyvoltine silkworm strains on efficiency of conversion of ingesta to cocoon and shell than control. Comparatively smaller consumption index, respiration, metabolic rate with superior relative growth rate, and quantum of food ingesta and digesta requisite per gram of cocoon and shell were shown; the lowest amount was in new polyvoltine strains compared to the control. Furthermore, based on the overall nutrigenetic traits utilized as index or ‘biomarkers’, three polyvoltine silkworm strains (RMG4, RMW2, and RMW3) were identified as having the potential for nutrition efficiency conversion. The data from the present study advances our knowledge for the development of nutritionally efficient silkworm breeds/hybrids and their effective commercial utilization in the sericulture industry.

Keywords: approximate digestibility, breed, consumption index, leaf-cocoon ratio, leaf-shell ratio, metabolic rate, silkworm

Abbreviations: AD, approximate digestibility; CI, consumption index; CD, critical difference; C, control; D/g cocoon, digesta per gram cocoon; D/g shell, digesta per gram shell; ECD, efficiency of conversion of digesta; ECI, efficiency of conversion of ingesta; I/g cocoon, ingesta per gram cocoon; I/g shell, ingesta per gram shell; MR, metabolic rate; RR, reference ratio; RGR, relative growth rate; SE, standard error

Correspondence: a ramesh_silk53@rediffmail.com, b lakshmicsrti@gmail.com, c sugnana27@yahoo.com, d drcmanuradha@gmail.com, e chitta34c@gmail.com, *Corresponding author

Editor: Allen Cohen was Editor of this paper.

Received: 5 March 2011 | Accepted: 29 June 2011 | Published: 22 January 2012

ISSN: 1536-2442 | Volume 12, Number 3

Ramesha C, Lakshmi H, Kumari SS, Anuradha CM, Kumar CS. 2012. Nutrigenetic screening strains of the mulberry silkworm, Bombyx mori, for nutritional efficiency. Journal of Insect Science 12:3 available online: insectscience.org/12.3


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