Production performance and economic traits of silkworms (Bombyx mori L., 1758) fed with mulberry tree leaves (Morus alba, var. Ichinose) significantly differ according to hybrid lines

摘要

Production performance of silkworm (Bombyx mori L., 1758) play a pivotal role in sericulture industry and good quality cocoon represents the economic driver of farms. Silkworms are monophagus insects and differences between cocoon characteristics may depend both on mulberry tree leaves quality as well as on genetic selection of hybrid lines. While a huge work was carried out to identify the best feeding sources to optimize yields, genetic types of silkworms with desirable production and economic traits were studied to a limited extent to date. This experimental feeding trial was carried out using a commercial variety of mulberry tree leaves (Morus alba var. Ichinose) to feed a total of 1600 silkworms in 4 replicates, allotted into 32 box consisting of 50 larvae each. Feed consumption, manure production and feed conversion ratios were monitored throughout the experimental period across five instars of 8 hybrid lines (200 larvae each). Efficiency, Profitability and Eco-compatibility were identified as criteria to evaluate the best performing hybrid lines: in descending order hybrids 32 x 31, 153 x 154 and 104 x 103 have appeared the best in terms of feed conversion ratio to larva weight gain and to cocoon weight, shell to cocoon ratio and wet manure per g of dry matter intake per silkworm. Our results point to promising outcomes as to animal selection to improve yields of silk production at farm level. Sustainable and modem sericulture industry can therefore point to raise genetically selected hybrid lines of silkworms together with opportune feeding practices, to optimize feed conversions and rationalize manure in farms.