Neglected and underutilised insects of Ghana: identification, spatial distribution and utilisation for food, feed and nutrition

Even though animal meat plays a vital role in human diet, there are growing concerns about the supply gap and the ecological footprint resulting from high production and consumption of animal meat. These studies were conducted to identify the major edible insects of Ghana and encourage their cultivation and consumption in the country. The study was also aimed at developing an entomophagical map of Ghana and evaluate how insects could contribute to food, feed and nutrition security in Ghana. The studies also evaluated social and environmental factors that affect entomophagy in Ghana with a view to initiating programmes for their use for human and poultry nutrition in Africa. Two thousand questionnaires were administered to randomly selected respondents in all the ten regions of Ghana. Nine species of major edible insects belonging to five orders were identified. The nine edible insects in Ghana are: the larvae of the palm weevil (Rhyncophorus phoenicis Fabricius), termites (Macrotermes bellicosus Smeathman), ground crickets (Scapteriscus vicinus Scudder), field crickets (Gryllus similis Chapman), house cricket (Acheta domesticus Linnaeus), grasshoppers (Zonocerus variegatus Linnaeus), locusts (Locusta migratoria Linnaeus), the shea tree caterpillar (Cirina butyrospermi Vuillot) and larvae of the scarab beetle (Phyllophaga nebulosa Harris). Proportionally, the scarab beetle (2%), field cricket (5%), shea tree caterpillar (8.7%), house cricket (9.5) and the locust (10%) were the least consumed insects whereas the palm weevil larvae (47.2%), termites (45.9%), ground cricket (33.3%) and grasshopper (30.5%) were the most consumed insects in Ghana.With the exception of the palm weevil, all the other edible insects are only available from May to December. iv Entomophagy was found to be influenced by age, gender, education and occupation. Also, entomophagy was more pronounced in rural areas than urban areas. The studies also revealed that entomophagy is practised across all age groups and gender. Proportionally, 90%, 78% and 74% of the aged (60+), middle age (31-50) and the youth (18-30) consume various edible insects, respectively. Over 87% of respondents who consume edible insects obtained them through hunting/trapping. An entomophagical map of Ghana was also developed to delineate the location and extent to which various edible insect species are utilized as food and feed. Proximate and comparative analyses of the nutritional chemistry of some identified entomophagical species were also done. The shea tree caterpillar (STC) C. butyrospermi contained the highest amount of crude protein of 63% while the Black Soldier Fly Larvae (BSFL) Hermetia illucens Linnaeus contained the highest percentage of ash (17%) with the Palm weevil larvae (PWL) recording the lowest percentage of ash (1.4%). The PWL had the highest fat content of 65.4%, followed by BSFL (18.0%). The predominant amino acid in house fly larvae (HSFL) Musca domestica Linnaeus was phenylalanine (36.5 μg/g), followed by methionine (30.1 μg/g) whiles the limiting amino acid was arginine (7.5 μg/g). The highest amino acids in PWL was phenylalanine (54.6 μg/g), followed by Isoleucine (53.0 μg/g) with the limiting amino acid being tyrosine (8.6 μg/g). Further experiments were conducted to develop a mass production system for BSFL, HSFL and PWL in the rural conditions of Ghana. Among the several organic wastes evaluated, the best yield for BSFL was from 3 kg moist spent grain (brewery waste) + 2 kg dry fish feed factory waste + 0.5 litre yeast (liquid) + 4.5 litres of water. For the HSFL, two formulations (2 kg chicken manure + 2 kg fish feed waste + 3-5 L water or 3 kg brewery waste + 1 kg chicken manure + 1 kg v Yeast + 1 L water) proved very useful for mass rearing of the maggots. The potential of the BSFL meal as a replacement for fish/soyabean meal in the diets of broilers was also investigated. The crude protein of BSFL (44.8) was the highest and T1 (BSFL+Soy) (20.8) recorded the lowest crude protein. The highest feed intake was recorded from T2 (BSFL+Fish) (5.7 kg) and the control T0 (Fish+Soy) registered the highest water intake (12.15 l). In terms of total weight gain and final weight, T2 was superior to T1 but statistically (p > 0.05) similar to the control. Conversely, the differences between feed conversion ratio (FCR) and mortality rate were not significant (p > 0.05). The differences in all chicken carcass parameters measured except for empty intestine and abdominal fat weights were significant (p < 0.05). Again, T2 was better (p < 0.05) than T1 for heart weight and liver weight. Wings, breast and thigh weights were significantly (p < 0.05) influenced by BSFL but not for drumstick, and back weights. Birds fed with T1 had relatively lighter (p < 0.05) wings compared to those fed with T2. Haematological parameters were not significantly (p > 0.05) different among treatments except for white blood cell count and mean cell volume. The research has demonstrated that, edible insects especially the shea tree caterpillar (STC) is a good source of unsaturated fatty acids, particularly linolenic acid which is required in the diets of the aged. The oils in edible insects are rich in polyunsaturated fatty acids such as linoleic and α-linoleic acids which are essential for the development of children and infants. The high content of desirable unsaturated fatty acids in some edible insects makes them important food components in the diet of humans. The larvae of the black soldier fly can be used as a replacement for fish/soy meal in the diets of broiler chicks so as to reduce the cost of poultry production.

Source: KNUST