The growing world population accompanied by urbanisation and improved economies has resulted in an increased demand for diets rich in animal proteins. The rearing of livestock by existing practices is also becoming increasingly difficult due to changing environmental conditions. The use of black soldier fly larvae (BSFL) grown on organic side streams (bioproducts) as feed for animals presents a sustainable alternative to conventional feed ingredients. The nutritional and compositional profile of BSFL reared on organic side streams and their potential to be used as animal feed has been extensively explored. However, little information is available on the chemical safety of BSFL reared on organic side streams. This review addresses the chemical safety hazards of BSFL reared on substrates spiked with different chemical contaminants, including heavy metals, mycotoxins, pesticides, and pharmaceuticals. BSFL were observed to excrete mycotoxins and were able to reduce the concentration of pesticides and pharmaceutical compounds in the substrate. Certain heavy metals were found to be accumulated in BSFL when grown on spiked substrate. Initial studies have also indicated that the growth parameters and composition of BSFL are not altered by the presence of microplastics and organic pollutants in the substrate. Information about these feed-safety issues will assist in developing regulatory frameworks and appropriate processing methods to mitigate these hazards, thereby providing a framework of risks for the commercialisation of BSFL destined for animal feed.
Flystrike remains a serious financial and animal welfare issue for the sheep industry in Australia despite many years of research into control methods. The present paper provides an extensive review of past research on flystrike, and highlights areas that hold promise for providing long‐term control options. We describe areas where the application of modern scientific advances may provide increased impetus to some novel, as well as some previously explored, control methods. We provide recommendations for research activities: insecticide resistance management, novel delivery methods for therapeutics, improved breeding indices for flystrike‐related traits, mechanism of nematode‐induced scouring in mature animals. We also identify areas where advances can be made in flystrike control through the greater adoption of well‐recognised existing management approaches: optimal insecticide‐use patterns, increased use of flystrike‐related Australian Sheep Breeding Values, and management practices to prevent scouring in young sheep. We indicate that breeding efforts should be primarily focussed on the adoption and improvement of currently available breeding tools and towards the future integration of genomic selection methods. We describe factors that will impact on the ongoing availability of insecticides for flystrike control and on the feasibility of vaccination. We also describe areas where the blowfly genome may be useful in providing impetus to some flystrike control strategies, such as area‐wide approaches that seek to directly suppress or eradicate sheep blowfly populations. However, we also highlight the fact that commercial and feasibility considerations will act to temper the potential for the genome to act as the basis for providing some control options.
The demand for animal proteins, especially from pork and poultry, is projected to increase significantly due to rapid growth in population and underlying socio-economic conditions. Livestock rearing using conventional feed ingredients is becoming challenging due to climate change and several other factors, thereby suggesting the need for alternative, viable and sustainable animal feed sources. The use of black soldier fly larvae (BSFL) (Hermetia illucens) as a component in animal feed is a promising candidate due to their ability to valorise different organic waste streams. The nutrient composition of BSFL reared on organic waste streams is also comparable to that of several conventional animal feed ingredients and varies depending upon the feed, rearing conditions, and the morphological stage of the larvae. The identification of organic waste is of importance as it can determine not only the composition but also the safety issues of BSFL as an animal feed ingredient. The objective of this study was to determine the ability of near-infrared (NIR) spectroscopy to trace the food waste used to grow BSFL. Samples of BSFL (5th and 6th instar BSFL; n = 50) obtained from a commercial production facility were analysed using NIR spectroscopy. Partial least squares discriminant analysis (PLS-DA) was employed to develop the models. The outcomes of this study revealed that NIR spectroscopy could distinguish different larval instars and suggested the importance of larval instars in developing calibration models for traceability applications. The developed PLS-DA model could predict the feed source used for rearing the 5th instar larvae (R2 value: 0.89) and 6th instar pre-pupae (R2 value: 0.91). This suggests that NIR spectroscopy could be used as a non-invasive traceability tool for BSFL and to assist in selecting the suitable time frame for larvae harvesting in commercial facilities.
The control of house flies, Musca domestica (L.), currently relies on the use of chemical insecticide spray and bait formulations. Entomopathogenic fungi, such as Metarhiziumanisopliae, may provide an alternative to these products. This study aimed to develop and evaluate a mycoinsecticide bait formulation containing a virulent M. anisopliae isolate. Five M. anisopliae isolates were screened against M. domestica and isolate M16 was selected for bait development. Bait formulations containing a variety of additives, including (Z)-9-tricosene, were tested for their ability to increase fly visitation. A bait formulation containing M. anisopliae and skim milk powder was found to have the highest house fly visitation and was subsequently compared to a conventional chemical bait in an efficacy assay. The chemical bait (0.5% imidacloprid) caused faster mortality than the mycoinsecticide bait, however, similar levels of mortality were achieved by 4–5 days’ post exposure. These results suggest that M. anisopliae mycoinsecticide baits may offer an alternative to conventional chemical insecticides for the control of house flies in suitable areas.