A systematic review of the effect of rearing substrate composition on the fatty acid profile of black soldier fly larvae (Hermetia illucens)

Date
2021-12
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: As the agricultural sector is faced with providing sufficient nutritious and affordable food for the global population, the need for more sustainable agricultural practices is highlighted. One of the ways to improve the sustainability of the overburdened agricultural sector is the use of feed ingredients that have a reduced impact on the environment, while still optimising production. The black soldier fly (Hermetia illucens) has been well researched as a protein source for both animal feed and human consumption, as it could augment more traditional protein sources such as soybean meal, which has a large environmental impact. The black soldier fly larvae are also high in lipids and have the potential to be utilized as a source of energy in the form of fatty acids. The use of black soldier fly larvae as a lipid source is however less well researched. Studies have shown that the larval fatty acid profile is affected by multiple factors including: nutrition, age and environmental conditions. In recent years, numerous studies have investigated the effect that the rearing substrate composition has on the larval fatty acid profile. The systematic review performed as part of this study aimed to consolidate and compare the findings of published research regarding this effect. Meta- analyses were incorporated into the systematic review to determine to which extent the concentrations of the individual fatty acids in the larval fatty acid profile are affected by the rearing substrate composition. The results suggested that black soldier fly larvaeā€™s importance as a source of lipids and the effect that nutrition has on their fatty acid profile is recognised by researchers globally and that the interest in the topic has increased in recent years. It did however also show that there is a lack of standardisation in terms of larval rearing trial methodologies, which has a potential impact on the larval fatty acid profile. The findings of the systematic review clarified to which extent the larval fatty acid profile can be changed through changes in the rearing substrate composition. The meta-analysis results indicated that the concentrations of many of the fatty acids are significantly affected by the rearing substrate composition. The largest effect was found for the lauric acid concentration. Subsequently the level of saturation, in other words the total amount of saturated-, monounsaturated- and polyunsaturated fatty acids, are also significantly affected by the rearing substrate composition. This information could contribute to more dynamic larval nutrition thereby tailoring the larval fatty acid profile to its intended purpose, whether that be animal feed, human consumption or another purpose such as biofuel production.
AFRIKAANSE OPSOMMING: Soos wat die landbou sektor streef om voldoende voedsame en duursame voedsel te voorsien aan die populasie, word die nood vir meer volhoubare landbou praktyke beklemtoon. Een van die maniere hoe volhoubaarheid van ā€˜n alreeds oorbelaste landbou sektor kan verbeter, is deur die gebruik van voerbestandele wat ā€˜n verminderde impak op die omgewing het en steeds produksie optimaliseer. Die venstervlieg (Hermetia illucens) is ā€˜n insekspesie wat al baie nagevors is as ā€˜n proteĆÆenbron vir beide voer en menslike gebruik. Dit verteenwoordig ā€˜n aanvulling vir meer tradisionele proteĆÆenbronne soos soja, wat ā€˜n groot impak op die omgewing het. Die venstervlieg larwes bevat ook baie lipiedes en het die potensiaal om gebruik te word as a bron van energie in die vorm van vetsure. Daar is egter minder navorsing gedoen op die gebruik van venstervlieg larwes as a lipied bron. Studies het al gewys that die larwes se vetsuurprofiel geaffekteer word deur meerdere faktore, insluitende voeding, ouderdom en omgewingstoestande. In die afgelope paar jaar is daar meer studies gedoen wat gefokus het op die effek van die groeisubstraatkomposisie op die larwes se vetsuur profiel. Die stelselmatige literatuurstudie wat deel gevorm het van hierdie studie het daarop gefokus om die bevindings van gepubliseerde navorsing te konsolideer en vergelyk. Meta-analises was ook geĆÆnkorporeer om te bepaal tot watter mate die konsentrasies van die individuele vetsure beĆÆnvloed word deur die groei susbtraat- komposisie. Die resultate het aangedui dat daar wĆŖreldwye belangstelling is in die venstervlieg larwes se potensiaal as ā€™n bron van lipiede en die effek wat voeding het op hulle vetsuur profiel. Dit het egter ook daarop aangedui dat daar ā€˜n gebrek aan standaardisering is in terme van die metodologieĆ« wat geĆÆmplimenteer word tydens die groeiproewe. Hierdie metogologiese variasies kan ook ā€˜n invloed hĆŖ op die larwes se vetsuur-profiel. Die stelselmatige literatuurstudie se bevindings verduidelik hoe die vetsuur-profiel van die larwes verander kan word deur wysigings aan te bring in the groeisusbtraatkomposisie. The meta- analise se resultate het aangedui dat die konsentrasie van meeste van die individuĆ«le vetsure beĆÆnvloed word deur die groeisubstraatkomposisie. Die grootste effek was gesien by lauriensuur. Gevolglik is dit ook moontlik om die vetsuur-profiel se vlak van versadiging, met ander woorde die konsentrasie van die versadigde, mono-onversadigde en poli- onversadigde vetsure, te beĆÆnvloed deur wysigings aan te bring in die groeisubstraat. Hierdie inligting kan hopelik bydra tot meer dinamiese larwevoeding. Daardeur is dit dan moontlik om die larwes se vetsuurprofiel aan te pas vir hulle uiteindelike doel, al is dit voer, kos of miskien ā€˜n ander doel soos biobrandstofproduksie.
Description
Thesis (MScAgric)--Stellenbosch University, 2021.
Keywords
Black soldier fly (Hermetia illucens) larvae -- Nutrition, Fatty acid -- Analysis, Black soldier fly as feed, Larvae -- Effect of temperature on, UCTD
Citation