Chitin Determination in Residual Streams Derived From Insect Production by LC-ECD and LC-MS/MS Methods

Chitin, a biopolymer present in fungi and arthropods, is a compound of interest for various applications, such as in the agricultural and medical fields. With the recently growing interest in the development of insect farming, the availability of chitin-containing residual streams, particularly the molting skins (exuviae), is expected to increase in the near future. For application purposes, accurate quantification of chitin in these insect sources is essential. Previous studies on chitin extraction and quantification often overlooked the purity of the extracted chitin, making the outcomes inconsistent and prone to overestimation. The present study aims to determine chitin content in the exuviae of three insect species mass-reared worldwide: black soldier fly (BSF), mealworm, and house cricket. Chitin was chemically extracted using acid and alkali treatments to remove minerals and proteins. The purity of extracted chitin was evaluated by hydrolyzing the chitin into glucosamine, followed by quantitative determination of the latter using two liquid chromatography methods: electrochemical detection (ECD) and tandem mass spectrometry (MS/MS). Both methods proved accurate and precise, without the need for labor-intensive derivatization steps. Pearson's correlation and Bland-Altman plots showed that the glucosamine determination results obtained by the two methods were comparable, and there is no consistent bias of one approach vs. the other. The chitin content in extracted residues ranged between 7.9 and 18.5%, with the highest amount found in BSF puparium. In summary, the study demonstrated that (1) the residual streams of the insect farming industry have a great potential for utilization as an alternative chitin source, and (2) both LC-ECD and LC-MS/MS are reliable for the quantitative determination of glucosamine in insect chitin.

The effects of high-monosaccharide diets on development and biochemical composition of white-eyed mutant strain of house cricket (Acheta domesticus)

Tryptophan (TRP) is one of the essential amino acids in the animal body. Its exogenicity and low concentrations mean that it can be regarded as one of the key regulatory molecules at the cellular as well as physiological level. It has been shown to have a number of essential functions, such as in the production of other biologically active molecules. The main objective of this project was to investigate the effects of a high monosaccharide diet (HMD) on a hemimetabolic insect—house cricket (Acheta domesticus) and a mutant strain with impaired visual pigment synthesis (closely related to the tryptophan and kynurenine (KYN) metabolic pathway)—white eye. This study was aimed at determining the effects of glucose and fructose on cricket development and biochemical composition. A parallel goal was to compare the response of both cricket strains to HMD. ELISA assays indicated dysfunction of the TRP-KYN pathway in white strain insects and an elevated KYN/TRP ratio. Biochemical analyses demonstrated the effects of HMD mainly on fat and glycogen content. A decrease in food intake was also observed in the groups on HMD. However, no changes in imago body weight and water content were observed. The results of the study indicate a stronger response of the white strain to HMD compared to the wild-type strain. At the same time, a stronger detrimental effect of fructose than of glucose was apparent. Sex was found to be a modulating factor in the response to HMD.

Possibility of Using House Cricket (Acheta domesticus) or Mulberry Silkworm (Bombyx mori) Pupae Meal to Replace Poultry Meal in Canine Diets Based on Health and Nutrient Digestibility

There has been increasing interest in using insects as sustainable protein sources for humans and animals. Therefore, this study aimed to explore the possibility of substituting poultry meal with house cricket (Acheta domesticus: AD) or mulberry silkworm (Bombyx mori: BM) pupae. Fifty healthy adult mixed-breed dogs were selected and divided into five experimental groups, which were fed, in amounts based on daily energy requirement, with a control diet, a diet with 10% AD, with 20% AD, with 7% BM, or with 14% BM. Days 0–22 and 23–28 of the experiment served as the adaptation and collection phases, respectively. Haematology and blood chemistry were collected at days 0, 14, and 28, and body weight, body condition score, feed intake, faecal output, faecal score, faecal moisture, and apparent total tract digestibility of dry matter and nutrients were measured during the collection phase. The results from this study suggested that AD and BM can replace poultry meal without any adverse consequences on all measured parameters (p > 0.05). Therefore, AD at 20% or BM at 14% can be used in canine diet formulations. However, long-term feeding trials should be conducted and should focus on clinical signs relating to hypersensitivity disorders.

Performance of the house cricket (Acheta domesticus) on by-product diets in small-scale production

As insect farming is becoming more popular in Europe and in the US, the use of food industry by-products in insects’ feed is drawing more attention. However, it is still unclear how to maximise the use of by-products in the feeds while meeting the nutritional requirements and maintaining profitable rearing yields with the current production technology. In this study, we conducted an experiment in Finnish small-scale cricket farming and laboratory conditions to determine whether five diet treatments, including by-product diets with barley mash and turnip rape, modify the overall fresh yield (kg), development time and feed conversion rate of the house crickets (Acheta domesticus). We discovered that the diets differed in the overall fresh cricket yield (kg) but not in the development time or the feed conversion rate of the crickets. The diets with a high proportion of by-product decreased the price of the feed but at the same time reduced the yield. Based on our results, complex by-product diets with the by-product proportion of 20-41% are the most suitable for house cricket rearing.

Effect of the house cricket (Acheta domesticus) inclusion and process temperature on extrudate snack properties

The demand for healthy, satiating, and convenient products is growing, with ready-to-eat expanded snacks being the preferred. These are produced made by extrusion, which is a versatile and efficient technology, with an immense potential to develop new food products. In addition to satisfy consumer requests, it is interesting to add alternative protein sources to these products, such as insects that have nutritional benefits and ecological advantages. The aim of this work is to evaluate the effect of extrusion temperature and enrichment with house cricket (Acheta domesticus) on properties of extruded snacks. Extrudates were produced with a single-screw extruder at two barrel temperatures (165 and 175 °C), formulated with corn flour and house cricket powder in mass ratios, 100:0, 95:5, 90:10, and 85:15. Water content, water activity, expansion, porosity, water absorption, water solubility indices; swelling index and hygroscopicity; colour, texture, protein content, in vitro digestibility, and protein bioaccessibility were measured. The results suggest that incorporating edible insects in extruded snacks can be a good alternative to the snacks on the market, since they maintain the appropriate physicochemical characteristics, especially when formulated at low temperatures. Further, they improve the protein content, with the recommended percentage use of 5 and 10% of house cricket, for the formulation of snacks with extrusion at 165 °C.

Most Effective Combination of Nutraceuticals for Improved Memory and Cognitive Performance in the House Cricket, Acheta domesticus

Background: Dietary intake of multivitamins, zinc, polyphenols, omega fatty acids, and probiotics have all shown benefits in learning, spatial memory, and cognitive function. It is important to determine the most effective combination of antioxidants and/or probiotics because regular ingestion of all nutraceuticals may not be practical. This study examined various combinations of nutrients to determine which may best enhance spatial memory and cognitive performance in the house cricket (Acheta domesticus (L.)). Methods: Based on the 31 possible combinations of multivitamins, zinc, polyphenols, omega-3 polyunsaturated fatty acids (PUFAs), and probiotics, 128 house crickets were divided into one control group and 31 experimental groups with four house crickets in each group. Over eight weeks, crickets were fed their respective nutrients, and an Alternation Test and Recognition Memory Test were conducted every week using a Y-maze to test spatial working memory. Results: The highest-scoring diets shared by both tests were the combination of multivitamins, zinc, and omega-3 fatty acids (VitZncPuf; Alternation: slope = 0.07226, Recognition Memory: slope = 0.07001), the combination of probiotics, polyphenols, multivitamins, zinc, and omega-3 PUFAs (ProPolVitZncPuf; Alternation: slope = 0.07182, Recognition Memory: slope = 0.07001), the combination of probiotics, multivitamins, zinc, and omega-3 PUFAs (ProVitZncPuf; Alternation: slope = 0.06999, Recognition Memory: slope = 0.07001), and the combination of polyphenols, multivitamins, zinc, and omega-3 PUFAs (PolVitZncPuf; Alternation: slope = 0.06873, Recognition Memory: slope = 0.06956). Conclusion: All of the nutrient combinations demonstrated a benefit over the control diet, but the most significant improvement compared to the control was found in the VitZncPuf, ProVitZncPuf, PolVitZncPuf, and ProPolVitZncPuf. Since this study found no significant difference between the performance and improvement of subjects within these four groups, the combination of multivitamins, zinc, and omega-3 fatty acids (VitZncPuf) was concluded to be the most effective option for improving memory and cognitive performance.