The interest in using byproducts from agro-food industries as a rearing substrate for insects is increasing rapidly. We investigated the influence of byproducts of vegetal origin (okara—a byproduct of soy milk production, maize distillers with solubles, brewer’s grains), used as rearing diet for black soldier fly larvae (BSFL), on the following parameters: biomass production, substrate reduction (SR), nutritional profile and in vitro digestibility, and larval gut microbiota. Hen diet was used as a control substrate. The highest larval biomass was collected on maize distillers, whereas the highest SR was observed on okara. The rearing substrate affected ash, ether extract, and chitin larval content. The BSFL reared on okara were characterized by a lower lauric acid content (17.6% of total fatty acids). Diets also influenced in vitro crude protein digestibility (%) for monogastrics, with the highest values for BSFL reared on maize distillers (87.8), intermediate for brewer’s grains and okara BSFL, and the lowest for hen BSFL (82.7). The nutritive value for ruminants showed a lower Net Energy for lactation for BSFL reared on hen diet than okara and dried maize distillers BSFL. The different byproducts showed an influence on the larval gut microbiota, with a major bacterial complexity observed on larvae fed with the hen diet. The neutral detergent fiber concentration of dietary substrate was negatively correlated with Firmicutes and Actinobacteria relative abundance. Insects valorized byproducts converting them into high-value larval biomass to be used for feed production. The results evidenced the effects of the tested byproducts on the measured parameters, underling the chemical composition importance on the final insect meal quality.

中文翻译：

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农业工业副产品对黑水虻（双翅目：Stratiomyidae）幼虫的生物转化、化学成分、体外消化率和微生物群的影响

使用农业食品工业的副产品作为昆虫饲养基质的兴趣正在迅速增加。我们研究了植物来源的副产品（豆渣——豆奶生产的副产品、具有可溶物的玉米蒸馏器、啤酒谷物），用作黑水虻幼虫 (BSFL) 的饲养日粮，对以下参数的影响：生物量产量、底物还原（SR）、营养成分和体外消化率以及幼虫肠道微生物群。母鸡日粮用作对照底物。在玉米蒸馏器上收集到最高的幼虫生物量，而在豆渣上观察到最高的 SR。饲养基质影响灰分、乙醚提取物和几丁质幼虫的含量。在豆渣上饲养的 BSFL 的特点是月桂酸含量较低（占总脂肪酸的 17.6%）。日粮还影响单胃动物的体外粗蛋白消化率 (%)，在玉米蒸馏器上饲养的 BSFL 的最高值 (87.8)，啤酒谷物和豆渣 BSFL 的中间值，以及母鸡 BSFL 的最低值 (82.7)。反刍动物的营养价值表明，用母鸡饲料饲养的 BSFL 的泌乳净能量低于豆渣和干玉米蒸馏器 BSFL。不同的副产品显示出对幼虫肠道微生物群的影响，在用母鸡饲料喂养的幼虫上观察到的主要细菌复杂性。膳食底物的中性洗涤纤维浓度与厚壁菌门和放线菌相对丰度呈负相关。昆虫将副产品转化为高价值的幼虫生物量，用于饲料生产。