This study evaluated survival and growth of Cambodian field crickets (Teleogryllus testaceus) during captivity when fed a set of local weed species, agricultural and food industry by-products. Wild individuals were caught at two locations in Cambodia, kept in pens and fed commercial chicken feed until the second generation off-spring hatched. First larval stage nymphs from this generation were collected and used in a 70-day feeding trial with one control treatment (chicken feed) and 12 experimental treatments (rice bran, cassava plant tops, water spinach, spent grain, residue from mungbean sprout production, and Alternanthera sessilis, Amaranthus spinosus, Commelina benghalensis, Cleome rutidosperma, Cleome viscosa, Boerhavia diffusa and Synedrela nodiflora). The crickets were kept in plastic cages and feed intake, weight and survival of crickets were recorded weekly. Overall survival did not differ between chicken feed and the experimental treatments with the exception of crickets fed B. diffusa, which had lower survival. From day 35 to day 49, survival on A. sessilis was also lower (P<0.05) than on chicken feed. There was no difference in weight between crickets fed chicken feed, cassava tops and C. rutidosperma. However, crickets fed A. sessilis, A. spinosus and B. diffusa weighed less than those fed chicken feed already at day 21. The feed conversion rate ranged from 1.6 to 3.9 and was ≤1.9 in crickets fed chicken feed, cassava plant tops and C. rutidosperma. Thus this study shows that it is possible, using simple means, to rear Cambodian field crickets. Cassava plant tops and C. rutidosperma both have great potential as cricket feed and the other weeds, with the exception of A. sessilis, A. spinosus and B. diffusa, agricultural and food industry by-products tested, also showed potential.

This study evaluated diets including whole or peeled (legs removed) crickets (Teleogryllus testaceus) in terms of diet digestibility, growth and nitrogen retention, using pigs as an animal model. The experiment included three iso-nitrogenous diets (18.4% crude protein) including either whole cricket meal (WC), body cricket meal (legs removed, BC) or fish meal (control) as the main protein source. Castrated male piglets (n=21, 30-45 days) with initial body weight 13.0±0.3 kg were allocated to one of the dietary treatments (7 piglets/treatment) in a fixed block design. The piglets were kept in single bamboo/wooden stalls with slatted floors and were adapted to the feeds and the housing for 5 days before starting the 25-day experiment. The diets were offered ad libitum, but close to appetite (approximately 5% of body weight). Feed intake was recorded and piglets were weighed every 5 days. During days 20-25, total collection of faeces and urine was performed. Dry matter and nutrient intake were higher for piglets fed the WC and BC diets than for those fed the control diet. From day 10, piglets fed BC and WC were heavier than piglets fed the control diet, but there were no differences between WC and BC. Dry matter digestibility was highest for diet WC, and ash, crude fibre and crude fat digestibility was higher for BC and WC than for the control diet. Feed conversion ratio was lower for the WC and BC diets than for the control diet, and nitrogen retention (% of digested) was higher. We concluded that field cricket meal is a nutritious feedstuff for mono-gastric animals, and most likely also for humans. Removal of legs did not facilitate or improve the digestibility values and nitrogen retention. Thus, in order to minimise food waste, crickets should not be peeled in this way if they are going to be processed into meal.

For almost a decade, edible insects have become promoted on a wider basis as one way to combat world hunger and malnourishment, although attempts to do so have a longer history. Contemporary researchers and consumers, particularly those without an entomophagous background, have been rising safety and sustainability concerns. The present contribution seeks a substantiated answer to the question posed above. The possible answer consists of different factors that have been taken into consideration. First, the species and its life cycle. It is mandatory to realize that what is labeled as “edible insects” stands for more than 2,140 animal species, not counting other edible, non-crustacean arthropods. Their life cycles are as diverse as the ecological niches these animals can fill and last between some days to several years and many of them may—or may not—be reproduced in the different farming systems. Second, the level of knowledge concerning the food use of a given species is important, be it traditional, newly created by research, or a combination of both. Third, the existence of a traditional method of making the use of the insect safe and sustainable, ideally from both the traditional and the modern points of view. Fourth, the degree of effectiveness of these measures despite globalization changes in the food-supplying network. Fifth, farming conditions, particularly housing, feeding (type, composition, and contaminants), animal health and animal welfare. Sixth, processing, transport, and storage conditions of both traditional and novel insect-based foodstuffs, and seventh, consumer awareness and acceptance of these products. These main variables create a complex web of possibilities, just as with other foodstuffs that are either harvested from the wild or farmed. In this way, food safety may be reached when proper hygiene protocols are observed (which usually include heating steps) and the animals do not contain chemical residues or environment contaminants. A varying degree of sustainability can be achieved if the aforementioned variables are heeded. Hence, the question if insects can be safe and sustainable can be answered with “jein,” a German portmanteau word joining “yes” (“ja”) and “no” (“nein”).

Samples of ready-to-eat snacks based on Lethocerus indicus, Gymnogryllus vietnamensis, Tarbinskiellus portentosus, Teleogryllus mitratus, Bombyx mori, Omphisa fuscidentalis, and Cybister limbatus were purchased in Cambodia and Thailand, and their proximate chemical composition (including Na and Cl) was analysed. Comparing the results with the few existing references from the literature (based on unprocessed specimens), marked differences occurred. This was expected as the insect chemical composition varies strongly intra- and interspecifically due to taxon, feeding, instar, and processing, among others. In general, the insects mainly consisted of fat (35 to 60%) and protein (25 to 38%), with 2 to 16% nitrogen-free extract, 2 to 15% fibre, 3 to 5% ashes, 0.4 to 1.6% Na, and 0.6 to 1.4% Cl (dry matter base). In this way, this contribution adds to the compositional knowledge about traditional insect-based foodstuffs. The combination of high fat and protein with low carbohydrates makes them suitable to combat nutrition disorders.