Productivity and Elemental/Chlorophyll Composition of Collard Greens in an Aquaponic System at Different Combinations of Media and Black Soldier Fly (Hermetia illucens) Larvae Frass Supplementations

Abstract

Black soldier fly (Hermetia illucens) larvae (BSFL) production will likely increase to meet the growing demand for sustainable protein and lipids. A by-product is “frass,” which is a mixture of mostly larval excrement but also chitin. This mineral-richby-product could be a valuable aquaponic supplement, but the information is limited. The aim of this study was twofold to determine if BSFL frass additions could enhance the production, mineral composition, and chlorophyll content of collard greens (Brassica oleracea var. viridis) after 10 weeks as well as the influence of culturing collard greens with or without media. Each aquaponic system contained 20 channel catfish (Ictalurus punctatus; initial mean weight of 128 g) that were fed twice daily to apparent satiation. Results showed that dissolved nitrogen, pH, and dissolved oxygen were unaffected ( p > 0.05 ) by BSFL frass additions. There was a significant media and BSFL frass effect ( p < 0.05 ) on total weight, individual weight, and total height of collard greens where the media/frass treatment led to a ninefold increase in weight compared to the no media/no frass treatment. Moreover, both media and BSFL frass significantly increased ( p < 0.05 ) the total chlorophyll content while extensive chlorosis was observed in the no media/no frass group. Manganese in collard greens was significantly increased ( p < 0.05 ) by BSFL frass. The best combination for collard green growth and preventing any chlorosis was the media/frass treatment, which may be due to an increase in various nutrients that were more accessible by biomineralization in the media.

Sub-Liquid and Atmospheric Measurement Instrument To Autonomously Monitor the Biochemistry of Natural Aquatic Ecosystems

“…Monitoring the physicochemical parameters can be beneficial for industrial applications too, such as in fish farms. Temperature, pH, dissolved oxygen, total suspended solids, ammonia, nitrite, and nitrate concentrations have to be continuously measured to evaluate the permissible levels for aquaponic systems that provide information about the survival, growth, and food intake of fish. , Also, pH is an excellent indicator to observe the nutritional profile in freshwater fishery sectors, including calcium, magnesium, iron, manganese, and zinc, and monitoring the electrical conductivity, pH, and oxidation–reduction potential becomes vital in brackish water fish cultures . The same parameters can also be used to assess the quality of groundwater that could be compromised by anthropogenic activities, industrial effluents, , and algal bloom contamination. , …”

Larval Frass of Hermetia illucens as Organic Fertilizer: Composition and Beneficial Effects on Different Crops

“…Insect frass is gaining popularity as an organic fertilizer due to its high concentration of vital plant nutrients and the presence of chitin, a component of the insect exoskeleton, which seems to stimulate plant defense mechanisms and growth [58]. Since insect farming is expanding as a sustainable alternative element for terrestrial and aquatic animal feed production, and for food waste management, the availability of frass also increases [59]. Frass can be considered a value product to use as biofertilizer, having demonstrating comparable efficacy to organic fertilizers, even when BSFL are fed on various types of substrates.…”

Utilizing Insect Frass (Faecal Matter): A Sustainable Approach to Organic Fertilization in Agriculture

“…It can serve as a valuable indicator of insect diversity in specific areas, aiding ecological studies and biodiversity assessments. Moreover, the nutrient content of insect frass makes it a suitable option for use as fish feed, contributing to the nutrition of aquatic species such as hybrid tilapia and channel catfish [25].…”