Evaluation of life cycle and nutrient content of Jamaican field crickets (Gryllus assimilis) reared on the dried rapeseed protein

Daniela Slavíková

Master's thesis

Abstract:

Edible insect rearing could provide a good alternative for protein production in the future. Thus, the theoretical part of diploma thesis is focused on review of nutritional value and rearing technology of the crickets. Insect production has a smaller environmental impact comparing to the traditional livestock farming due to the insect’s ability to convert organic side streams, and so, the work also deals with the possible use of waste and agricultural by-products as an alternative feed. The practical part is devoted to the effect of addition of dried rapeseed cakes into the diet of Gryllus assimilis and its impact on their life characteristics and basic nutrient content. In this experiment, the soybean in the insect feed mixture was replaced by rapeseed cakes as the food industry by-product. The crickets were reared on the four different feed substrates containing different proportions of rapeseed cakes (17.5, 35, 52.5 and 70 %) and control group (chicken feed) in three repetitions. The whole life cycle was observed as well as the individual weights of the crickets were recorded. After cricket’s harvest, laboratory analysis were performed to determine the essential nutrients. Based on the statistical evaluation, the addition of rapeseed protein into the feed mixtures did not influence the content of basic nutrients and life characteristics of Gryllus assimilis. The nutritional value of the crickets, precisely the amount of dry matter, protein, fat, chitin, and ash content was in accordance with the cited literature, thus all feed mixtures enriched by rapeseed cakes were within the nutritional optimum. In conclusion, the agricultural by-product – rapeseed cakes – could possibly be utilized as a part of the cricket feeds without any negative impact of its quality. Therefore, the obtained results may be used to improve the environmental sustainability of insect feed substrates, insect rearing technology and advance the goals of circular economy.

Keywords

edible insects, novel food, food by-products, sustainability

Language used: English

Date on which the thesis was submitted / produced: 18. 4. 2021

Thesis defence

• Supervisor: Ing. Martin Kulma, Ph.D.

Czech University of Life Sciences Prague

Faculty of Agrobiology, Food and Natural Resources

Master programme:
Sustainable Agriculture and Food Security