Índices de consumo e utilização de dietas artificiais e folhas de amoreira por larvas de Bombyx mori L. (Lepidoptera: Bombycidae)

EnglishDespite all the benefits that an artificial diet can make to the Bombyx mori rearing, as labor savings, greater production efficiency, raising during creating unfavorable conditions, and rearing virtually free of diseases, was not yet developed an adequate artificial diet for all larval stages. However , in Japan the use of artificial diets is highly diffused to rearing first and second instars silkworm larvae, covering about 50 % of the productions. The objective of this study was to determine the effects of offering artificial diets in the early instars on the consumption of natural diet and metabolism in late instar larvae of B. mori. Three types of treat systems were tested: (i) artificial diet adapted from Miao & Jiang for the first larvae instar and natural diet for others instars; (ii) similar to the previous system, differing from it by the adapted Miao & Jiang diet have been offered to larvae of first and second instars; (iii) artificial diet adapted from Sadiq for the first larvae instar and natural diet for others instars; and (iv) natural diet for all larval instars (check). As natural diet it was used fresh mulberry leaves of the hybrid ‘Shima-Miura”, that was offered five times a day. Consumption and metabolism of fifth instar larvae (late larval stage) were studied by assessing: relative consumption rate, the relative metabolic rate, relative growth rate, efficiency of conversion of ingested food into biomass; conversion efficiency the food digest into biomass; and approximate digestibility. No significant effect of feeding treatment systems was observed in any biological parameter studied, indicating that the supply of artificial diets Sadiq for the first instar larvae, or Jiang & Miao diet for the first and second instars larvae, were not affecting the consumption of natural diet and metabolism of fifth larvae of B. mori, showing that they can be incorporated into a silkworm food system. portuguesA pesar de todos os beneficios que uma dieta artificial pode representar para a criacao de Bombyx mori, como economia de trabalho, maior eficiencia na producao, criacao em epoca desfavoravel e praticamente livre de doencas, ainda nao foi desenvolvido um meio artificial adequado para todos os estagios larvais do inseto. Contudo, no Japao o uso de dietas artificiais e altamente difundido para a criacao dos dois primeiros instares da lagarta de bicho-da-seda, abrangendo cerca de 50% das criacoes. Assim, o objetivo deste trabalho foi determinar os efeitos do oferecimento de dietas artificiais nos instares iniciais sobre o consumo de dieta natural e metabolismo no instar final de lagartas de B. mori. Foram testados tres tipos de sistema de alimentacao: (i) dieta artificial adaptada de Miao & Jiang para larvas de primeiro instar e dieta natural para os demais instares; (ii) sistema semelhante ao anterior, diferindo dele pela a dieta adaptada de Miao & Jiang ter sido oferecida para lagartas de primeiro e segundo instares; (iii) dieta artificial adaptada de Sadiq para larvas de primeiro instar e dieta natural para os demais instares; e (iv) dieta natural para todos os instares larvais (Testemunha). Como dieta natural foram utilizadas folhas frescas de amoreira do hibrido ‘Shima-Miura’ oferecidas cinco vezes ao dia. O consumo e metabolismo de lagartas de quinto instar (estadio larval final) foram estudados avaliando-se a Taxa de Consumo Relativo; a Taxa Metabolica Relativa; a Taxa de Crescimento Relativo; a Eficiencia da Conversao do Alimento Ingerido em Biomassa; a Eficiencia de Conversao do Alimento Digerido em Biomassa e a Digestibilidade Aproximada. Nao foi observado efeito significativo dos sistemas de alimentacao sobre nenhum dos parâmetros avaliados, indicando que a oferta das dietas artificiais de Sadiq para lagartas de primeiro instar; ou de Miao & Jiang para lagartas de primeiro, ou de primeiro e segundo instares; nao afetam o consumo de dieta natural e metabolismo de lagartas de quinto e ultimo instar de B. mori, podendo ser incorporadas nos sistemas de alimentacao do bicho-da-seda.