Background and Aim: Hermetia illucens, a black soldier fly, is widely recognized for sustainable recycling of organic waste. Black soldier fly larvae (BSFLs) can consume various types of biowastes and convert them into nutrient-rich biomass, including proteins, lipids, chitin, and minerals. This study investigated the best extraction method by comparing the fatty acid profiles, percentage yield, and antioxidant properties of BSFL oil extracted using different extraction methods. Materials and Methods: The physicochemical properties, fatty acid profile, and free radical scavenging ability of BSFL oil were analyzed using six extraction methods. Results: Ultrasonic extraction with hexane resulted in the highest yields compared with different extraction methods. Lauric acid (28%–37%) was the most abundant fatty acid in all extracts, followed by palmitic acid, myristic acid, oleic acid, and linoleic acid. Compared with other methods, aqueous extraction showed the highest lauric acid composition and free radical scavenging activities. In addition, high-temperature aqueous extraction resulted in higher oil yield and free radical scavenging activities than low-temperature extraction. Conclusion: High-temperature aqueous extraction is the best extraction method because it is rich in lauric acid, has antioxidant ability, and can be further developed to produce novel sustainable biomaterials for humans and animals. Keywords: black soldier fly, extraction method, fatty acid, Hermetia illucens.

Culture of the freshwater pearl mussel, Hyriopsis (Limnoscapha) myersiana, was carried out in three consecutive steps: (1) culture of glochidia larvae in artificial media, (2) rearing the early juveniles (0–120 days old) in a nursery, and (3) rearing the juveniles (120–360 days old) in an earthen pond. The percentage survival of glochidia in standard tissue culture medium (M199) supplemented with common carp plasma was 95±2.5. All surviving larvae (100%) transformed to juveniles, the duration of transformation being 8 days. The early juveniles (0–60 days old) were fed with a mixture of four selected phytoplankton species (Chlorella sp., Kirchneriella incurvata, Navicula sp. and Coccomyxa sp.). The survival rate of juveniles was 8±0.2%. The average length of these juveniles increased from 0.13±0.01 mm to 1.41±0.16 mm and the average height from 0.16±0.01 mm to 0.98±0.09 mm. Subsequently, 60–120-day juveniles were fed with one of the same four phytoplankton species or a combination of the four. Feeding the juveniles with K. incurvata resulted in the highest survival rate (65±8.32%), with an average length of 3.46±0.04 mm and an average height of 1.94±0.04 mm. Finally, the 120–360-day juveniles were cultured in an earthen pond. There were progressive changes in average weight (0.0037±0.002 g to 11.24±5.02 g), length (3.48±0.39 mm to 54.08±6.21 mm), height (1.97±0.24 mm to 25.09±2.48 mm) and width (0.98±0.06 mm to 12.28±3.21 mm) from 120 to 360 days. The average growth rates per day of these parameters were 0.0497±0.01 g, 0.2414±0.15 mm, 0.0975±0.08 mm and 0.0493±0.03 mm, respectively. H. (L.) myersiana juveniles developed the complete structural composition of the adult by 160 days, and at 360 days, gametogenesis was complete.

The morphological development and the sequence of organogenesis from glochidium to the early juvenile stage of the freshwater pearl mussel, Hyriopsis bialatus, were observed. Larvae of H. bialatus were cultured in standard tissue culture medium (M199) supplemented with common carp (Cyprinus carpio) plasma and they showed transformation within 10 days. Larval samples were collected every 2 days during glochidia development and subjected to histological processing. Three types of cell masses were developed during this period: the ventral plate (the foot rudiment), lateral pits (the gill rudiment), and the oral plate or endodermic sac (the origin of the digestive tract). The ventral plate gave rise to two foot lobes which fused into a single lobe. The gills were developed from the lateral pits next to the ventral plate, forming a pair of gill buds that became elongated and turned into gill bars. The digestive tract began with the formation of mouth by invagination of the oral plate (or endodermic sac) and formation of a tube underneath the growing foot. Several controversial aspects of organogenesis have been inferred, e.g., de novo formation of the anterior and posterior juvenile adductors, the fate of the mushroom body structure, and foot lobe formation from two separate precursor lobes. A mushroom body protruded into the mantle cavity and remained there throughout the transformation period. Moreover, the evidence of a supporting band (mucoid structure) in the mature glochidium of H. bialatus has never been reported in other freshwater mussel species, and its function and composition need to be further investigated.

The macroscopic and microscopic structures of male and female gonads of Hyriopsis (Hyriopsis) bialatus are described. The sex of individuals was determined from the presence or absence of sperm and eggs in the gonadal fluid under light microscopy analysis. The gonads of both sexes are composed of numerous acini. Male acini contain germ cells at various developmental stages of typical spermatogenesis, i.e., spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa. A striking feature is the presence of morulae with atypical spermatogenesis, interspersed among typical germ cells. Early stage morulae comprise a few large spermatogonia, those at middle stage contain spermatocytes and those at late stage consist of spermatids and spermatozoa. Female acini include oogonia and five different stages of developing oocytes. Stage 1 oocytes are attached to the acinar wall without yolk vesicles and stalk. Stage 2 oocytes have a stalk connected to the acinar wall. Stage 3 oocytes are larger in size, having yolk vesicles accumulated both at the base of the stalk and at the periphery of nucleus. Stage 4 oocytes have yolk vesicles dispersed throughout the cytoplasm. During this period, the basophilia of cytoplasm is replaced by eosinophilic yolk. Stage 5 oocytes contain both mature and developing oocytes. Immature oocytes are surrounded by a vitelline layer and attached to the acinar wall by a narrow stalk. Mature oocytes, however, are completely detached from the acinar wall, being released into the acinus lumen. The male and female germinal ducts are lined by a simple ciliated columnar epithelium. Several acini are connected to a single germinal duct. Numerous mature germ cells are found in the lumen of the germinal duct. No change was detected in the histological structure of male and female gonads collected at different times of the year. Female gonads collected at different stages of marsupial development are also morphologically similar. These observations strongly suggest that H. (H.) bialatus has no distinct reproductive season and may be suitable for commercial culture.