Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.

https://link.springer.com/content/pdf/10.1007%2Fs10811-016-0974-5.pdf

Algae as nutritional and functional food sources: revisiting our understanding

Review on the use of insects in the diet of farmed fish: Past and future

BACKGROUND
Black soldier fly larvae are converters of organic waste into edible biomass, of which the composition may depend on the substrate. In this study, larvae were grown on four substrates: chicken feed, vegetable waste, biogas digestate, and restaurant waste. Samples of prepupae and substrates were freeze-dried and proximate, amino acid, fatty acid and mineral analyses were performed.

RESULTS
Protein content of prepupae varied between 399 and 431 g kg−1 dry matter (DM) among treatments. Differences in amino acid profile of prepupae were small. On the other hand, the ether extract (EE) and ash contents differed substantially. Prepupae reared on digestate were low in EE and high in ash (218 and 197 g kg−1 DM, respectively) compared to those reared on vegetable waste (371 and 96 g kg−1 DM, respectively), chicken feed (336 and 100 g kg−1 DM, respectively) and restaurant waste (386 and 27 g kg−1 DM, respectively). Prepupal fatty acid profiles were characterised by high levels of C12:0 in all treatments.

CONCLUSION
Since protein content and quality were high and comparable for prepupae reared on different substrates, black soldier fly could be an interesting protein source for animal feeds. However, differences in EE and ash content as a function of substrate should be considered. © 2016 Society of Chemical Industry

Nutritional composition of black soldier fly (Hermetia illucens) prepupae reared on different organic waste substrates

The present opinion has the format of a risk profile and presents potential biological and chemical hazards as well as allergenicity and environmental hazards associated with farmed insects used as food and feed taking into account of the entire chain, from farming to the final product. The opinion also addresses the occurrence of these hazards in non-processed insects, grown on different substrate categories, in comparison to the occurrence of these hazards in other non-processed sources of protein of animal origin. When currently allowed feed materials are used as substrate to feed insects, the possible occurrence of microbiological hazards is expected to be comparable to their occurrence in other non-processed sources of protein of animal origin. The possible occurrence of prions in non-processed insects will depend on whether the substrate includes protein of human or ruminant origin. Data on transfer of chemical contaminants from different substrates to the insects are very limited. Substrates like kitchen waste, human and animal manure are also considered and hazards from insects fed on these substrates need to be specifically assessed. It is concluded that for both biological and chemical hazards, the specific production methods, the substrate used, the stage of harvest, the insect species and developmental stage, as well as the methods for further processing will all have an impact on the occurrence and levels of biological and chemical contaminants in food and feed products derived from insects. Hazards related to the environment are expected to be comparable to other animal production systems. The opinion also identifies the uncertainties (lack of knowledge) related to possible hazards when insects are used as food and feed and notes that there are no systematically collected data on animal and human consumption of insects. Studies on the occurrence of microbial pathogens of vertebrates as well as published data on hazardous chemicals in reared insects are scarce. Further data generation on these issues are highly recommended.

https://www.zora.uzh.ch/id/eprint/119973/1/4257.pdf

Risk profile related to production and consumption of insects as food and feed : EFSA Scientific Committee

With a growing world population, increasingly demanding consumers, and a limited amount of agricultural land, there is an urgent need to find alternatives to conventional meat products. Livestock production is, moreover, a leading cause of anthropogenic-induced climate change. To mediate this, more sustainable diets are needed, with reduced meat consumption or the use of alternative protein sources. Insects are promoted as human food and animal feed worldwide. In tropical countries, edible insects are harvested from nature, but overexploitation, habitat changes, and environmental contamination threaten this food resource. Therefore, sustainable harvesting practices need to be developed and implemented. We provide examples of (1) aquatic insects whose populations are threatened by pollution, (2) caterpillar species in Africa that are disappearing due to overexploitation and habitat change, (3) edible insects species that are considered pests in agro-ecosystems, and (4) edible insect species that can be conserved and enhanced in forest management systems. Insect farming can be conducted either on small-scale farms or in large-scale industrialized rearing facilities. We review the environmental sustainability of insect farming compared to livestock production. The major environmental advantages of insect farming compared to livestock production are as follows: (1) less land and water is required; (2) greenhouse gas emissions are lower; (3) insects have high feed conversion efficiencies; (4) insects can transform low-value organic by-products into high-quality food or feed; and (5) certain insect species can be used as animal feed or aqua feed. For instance, they can replace fish meal, which is becoming increasingly scarce and expensive. However, edible insect species intended for production should be screened for risks to humans, animals, plants, and biodiversity.

https://link.springer.com/content/pdf/10.1007%2Fs13593-017-0452-8.pdf

The environmental sustainability of insects as food and feed. A review

State-of-the-art on use of insects as animal feed.

Seaweeds for livestock diets: A review

Towards sustainable animal diets: A survey-based study☆

Increasing demand for livestock products will impose a huge demand on feed resources. Biophysical factors such as scarcity of land, soil and water, food–fuel–feed competition, ongoing global climate change and increasing competition for arable land and non-renewable resources such as fossil sources and minerals are challenging the sustainability of feed production systems. Efficient use of available feed resources is key to efficient animal production and food security. It is impossible to effectively manage a resource if its availability is not known. While Feed inventories or Feed assessments provide critical information on feed productive capacities and feed availability at a regional/country level, the sufficiency of the feed supply can only be gauged relative to demands for feeds. Essentially, this comparison between livestock requirements and feed supplies constitutes the Feed balance. In many countries Feed Balances are not usually available or accurate despite their strategic role for livestock development opportunities, for providing input data into country level food input-output analyses and for emergency prevention. Estimation of Feed Balance at a national level requires information on the amounts of feed resources available and their energy content, livestock population and herd structure. Likewise, reliable and harmonised herd structure data are also lacking. Information on what proportions of cereals being produced in a country that are diverted to feed production is critical for assessing food security situations in countries. In most situations these data are not available for most developing countries. Equally important is the information on the feeding systems i.e. how different feed resources are being fed to livestock. Assessment of environmental impacts of livestock and development of optimal feeding strategies rely on information about feeding systems and data on feed balance. Feed-use efficiency and decrease in release of environmental pollutants from livestock production systems hinges on feeding of balanced rations; and for their preparation, availability of reliable data on chemical composition and nutritional value of feed resources is a must. Also for reducing wastages, ensuring food safety through enhancing feed safety and promoting international trade, data on the presence of microbial contaminants including mycotoxins, heavy metals, antibiotic and pesticide residues must also be strengthened. Development of a National Feed Resource Information Systems linked to a Global Feed Resource Information Systems should be considered. Feed Inventories, Feed Balance, Feeding Systems, and Feed Quality including Feed Contaminants should be considered as integral components of an overall strategy or options that integrate technical (genetics, health and nutrition), policy and institutional interventions for using resources more efficiently to produce more food and feed. Both policy makers and animal feed and crop scientists have a role to play in making this possible.

Philippe Ankers

Papers

State-of-the-art on use of insects as animal feed.

Seaweeds for livestock diets: A review

Towards sustainable animal diets: A survey-based study☆

A need for generating sound quantitative data at national levels for feed-efficient animal production