Department of Crop Production and Management

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Browsing Department of Crop Production and Management by Author "Angwech, Harriet"

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    Growth, survival and nutritional composition of the edible long-horned Grasshopper Ruspolia differens (Serville) reared on diets from oil seed by-products.
    (Springer Nature, 2025) Sengendo, Francis; Egonyu, James Peter; Valtonen, Anu; Noyens, Isabelle; Angwech, Harriet; Alaroker, Martha Franny; Nyeko, Philip; Malinga, Geoffrey Maxwell; Miert, Sabine Van
    The long-horned edible grasshopper Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) is a significant food source in Southern and Eastern Africa due to its rich nutritional profile. The declining yields from wild harvests have driven research into developing methods for mass rearing of R. differens. Despite extensive efforts, identifying cost-effective nutritious diets has been challenging. This study tested eight diets including seven diets constituted from oil seed by-products, i.e., sunflower seed cake, shea seed cake, oil palm seed cake and one control diet (germinated finger millet). The experiment was arranged as a randomised unreplicated block design. Survival of neonates to adults and adult weight of R. differens reared on sole sunflower seed cake and combinations of either oil palm seed cake or shea seed cake with germinated finger millet were statistically comparable to the R. differens reared on sole germinated finger millet (control); whereas no R. differens survived on any of the diets containing shea seed cake and the sole oil palm seed cake diet. Germinated finger millet increased the insect’s crude fat, carbohydrates and mono-unsaturated fatty acids. Conversely, R. differens reared on oil seed by-products-based diets had the highest contents of protein, minerals and polyunsaturated fatty acids than those raised on germinated finger millet. We conclude that (i) sole sunflower seed cake and/or a combination of the same or oil palm seed cake with 50% germinated finger millet are alternative diets to sole germinated finger millet in the mass rearing of R. differens and (ii) the diets based on oil seed by-products can be used to enhance the content of protein, mineral and polyunsaturated fatty acids of R. differens. We recommend further studies to increase the content of alpha linolenic acid in these diets to produce R. differens which is more nutritionally suitable for human consumption.
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    Strides in farming edible African bush cricket, Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) in East Africa : a systematic review of rearing protocols.
    (Springer Nature, 2025) Malinga, Maxwell Geoffrey; Angwech, Harriet; Alemu, Hussen Mohammed; Valtonen, Anu; Nyeko, Philip; James Peter Egonyu
    The edible African bush cricket, Ruspolia differens (Serville), is the most sought-after nutrient-dense edible insect in East Africa, with the potential to boost employment and income opportunities and ensure food and nutritional security. However, this potential is curtailed by the reliance on the limited and unstable harvests from its wild populations. Recently, significant effort has gone into developing protocols for domesticating this species, but this information is scattered in literature and limits the standardization of rearing techniques. This contribution reviews recent research on edible R. differens rearing protocols in East African region with a view to improving its rearing practices. We searched published articles from four databases including PubMed, Google Scholar, Scopus and Web of Science following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) method. Of the 99 records identified, 36 reviews met inclusion criteria. We found that this species can be reared from egg to adult in a relatively short time on grass leaves, inflorescences and grains as well as on artificial diets, side-streams from industry and agricultural by-products, and at relatively high densities. More diversified diets lead to shorter development time, increased adult fresh weight, and enhanced female fecundity compared to single or less diversified diets. Increasing the protein levels in the diet by up to 17% enhances the growth, development and survival of R. differens. The suitable temperature for R. differens rearing is 28–30 °C. Suitable rearing density for young R. differens nymphs should not exceed 36 nymphs per liter, as higher densities significantly increase nymph mortality rapidly over time. A promising egg-laying medium for larger scale production is an artificial folded plastic cloth (one side covered with short fleece). We also identify knowledge gaps and challenges that need to be tackled before scaling up technologies for R. differens mass production in the East African region. Our review offers suggestions to entrepreneurs and investors who wish to finance R. differens farming endeavors.
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    Supplementation of maize bran with either sunflower or oil palm seed cakes improves growth and nutritional value of the edible house cricket (Acheta domesticus).
    (Wiley, 2025) Sengendo, Francis; Egonyu, Peter James; Valtonen, Anu; Noyens, Isabelle; Angwech, Harriet; Alaroker, Franny Martha; Nyeko, Philip; Malinga, Maxwell Geoffrey; Miert, Van Sabine
    The house cricket, Acheta domesticus (Linnaeus) (Orthoptera: Gryllidae) is one of the major insects successfully domesticated for food around the world. However, expensive feed is still a major challenge in the production of the insect, leading to low returns. This study aimed at developing an alternative diet for mass rearing of A. domesticus. We tested five diets, namely commercial chicken mash (CCM; control diet), maize bran supplemented with 50% sunflower seed cake (SFC50), 50% shea seed cake (SBC50), 50% oil palm seed cake (POC50), and 25% maize bran+25% of each of the oil seed cakes (MSSP25). The experiment was arranged as a randomized unreplicated block design with 50 blocks, each containing one replicate of each diet treatment. Survival of A. domesticus fed on maize bran supplemented with either sunflower seed cake or oil palm seed cake was comparable to that of those fed on the control diet. However, emerging adults on oil seed supplemented diets (SFC50 and POC50) were heavier than their counterparts raised on the control diet. The shortest development time was observed among A. domesticus fed on 50% sunflower seed cake compared to all other diets. Acheta domesticus fed on the control diet was richer in protein, while those reared on maize bran supplemented with either sunflower seed cake or oil palm seed cake contained higher levels of fat, minerals (sodium, calcium, and iron) and polyunsaturated fatty acids (PUFAs). We conclude that supplementation of maize bran with 50% of either sunflower seed cake or oil palm seed cake improves survival and weight gain of A. domesticus and shortens their development time. In addition, these diets modify the nutritional composition of A. domesticus, especially lipids, minerals, and PUFAs. We recommend the use of SFC50 and POC50 as alternative diets to commercial chicken mash in the mass production of A. domesticus. KEYWORDS: circular economy, dietary supplementation, fatty acids, mass production, minerals, nutritional composition, nutritional profile, oil seed cake, orthoptera, proximate composition