Rodjaroen Somrak, Thongprajukaew Karun, Khongmuang Puridet, Malawa Saowalak, Tuntikawinwong Kimhun, Saekhow Suktianchai
Department of Agriculture, Faculty of Science and Technology, Nakhon Si Thammarat Rajabhat University, Nakhon Si Thammarat 80280, Thailand.
Department of Applied Science, Faculty of Science, Prince of Songkla University, Songkhla 90112, Thailand.
Insects. 2020 Jun 26;11(6):393. doi: 10.3390/insects11060393.
Mealworm larvae () are edible insects consumed in feed and food. In the current study, the optimal harvesting time of mealworm larvae for use as aquafeed was investigated during the ages of 30-90 days after hatching (DAH). Development of digestive enzymes, proximate composition, and in vitro protein digestibility using digestive enzymes from African catfish () and Nile tilapia (), were used as criteria. The specific activities of pepsin and trypsin significantly decreased with age ( < 0.05) from the first harvesting time until 50 and 45 DAH, respectively, while steadiness in these enzyme activities was observed onwards. Chymotrypsin specific activity appeared constant across all harvesting times. The specific activity of amylase significantly decreased in the later stages of development, while cellulase exhibited a different pattern suggesting it has a major role in dietary fiber utilization relative to starch. Regarding proximate compositions of the mealworm larvae, the moisture and ash contents decreased significantly with age, while the protein content exhibited the opposite trend with the highest contents from 60 to 90 DAH. Crude lipid was generally fairly constant, but its lowest value was observed in the earliest stage. In vitro protein digestibility was not significantly different across all harvesting times for both fish species, except for the significantly decreased digestibility value at 65 DAH relative to 30 and 35 DAH for Nile tilapia. However, based on the economic benefits of time for growth increment and proximate chemical composition, approximately 60 DAH is proposed as suitable for harvesting mealworm larvae to be used in fish feed.
黄粉虫幼虫是用于饲料和食品中的可食用昆虫。在本研究中，研究了孵化后30 - 90天（DAH）期间用作水产饲料的黄粉虫幼虫的最佳收获时间。以消化酶的发育、近似成分以及使用非洲鲶鱼（）和尼罗罗非鱼（）的消化酶进行的体外蛋白质消化率为标准。从首次收获时间到分别为50和45 DAH时，胃蛋白酶和胰蛋白酶的比活性随年龄显著降低（<0.05），而从那时起观察到这些酶活性保持稳定。在所有收获时间里，胰凝乳蛋白酶的比活性似乎保持不变。淀粉酶的比活性在发育后期显著降低，而纤维素酶表现出不同的模式，表明其在膳食纤维利用方面相对于淀粉具有主要作用。关于黄粉虫幼虫的近似成分，水分和灰分含量随年龄显著降低，而蛋白质含量呈现相反趋势，在60至90 DAH时含量最高。粗脂肪总体上相当稳定，但在最早阶段观察到其最低值。除尼罗罗非鱼在65 DAH时相对于30和35 DAH的消化率值显著降低外，两种鱼类在所有收获时间的体外蛋白质消化率没有显著差异。然而，基于生长增量时间的经济效益和近似化学成分，建议大约60 DAH适合收获用于鱼饲料的黄粉虫幼虫。
