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Black soldier fly (BSF) larvae, Hermetia illucens L. (Diptera: Stratiomyidae), bio-convert organic side streams into high-quality biomass, the composition of which largely depends on the side stream used. In the present study, BSF larvae were reared on feed substrates composed of dried brewers’ spent grains, each supplemented with either water, waste brewer’s yeast, or a mixture of waste brewer’s yeast and cane molasses to obtain 12 different substrates: barley/water, barley/yeast, barley/yeast/molasses, malted barley/water, malted barley/yeast, malted barley/yeast/molasses, malted corn/water, malted corn/yeast, malted corn/yeast/molasses, sorghum-barley/water, sorghum-barley/yeast, and sorghum-barley/yeast/molasses. The crude protein, fat, ash, and mineral contents of the BSF larvae fed each feed substrate were quantified by chemical analyses. The effect of substrate, supplementation, and their interaction on crude protein, fat, and ash contents of BSF larval body composition was significant. Calcium, phosphorus, and potassium were the most abundant macrominerals in the larvae and their concentrations differed significantly among substrates. These findings provide important information to support the use of BSF larval meal as potential new source of nutrient-rich and sustainable animal feed ingredients to substitute expensive and scarce protein sources such as fishmeal and soya bean meal.

Global population growth, an increasing demand for animal products and scarcity of conventional feed ingredients drive the search for alternative protein sources for animal feed. Extensive research indicates that insects provide good opportunities as a sustainable, high quality and low-cost component of animal feed. Here, we discuss how insect farming can promote inclusive business for smallholder farmers in the agribusiness value chain. Inclusive business models involving insects as ingredients in feed may contribute to solving socio-economic and environmental problems in developing countries, aligning with the United Nations’ Sustainable Development Goals. With low initial capital investments, smallholder insect farmers have good opportunities to increase productivity, improve their livelihood and contribute to food security and a circular economy.

Using black soldier fly (BSF, Hermetia illucens) larvae as a novel protein source substituting fishmeal (FM) in animal feeds is globally gaining momentum. BSF can be reared on agro-industrial residues. However, incorporating BSF larval meal (BSFLM) into finisher pig diets has received inadequate attention. This study evaluated the effects of replacing dietary FM with BSFLM on growth, carcass traits and meat quality of finisher pigs. A control diet (including FM: 0% BSFLM) was compared with four dietary levels of replacement of FM with BSFLM at 25, 50, 75 or 100%. Forty hybrid pigs (crossbreeds of purebred Large White and Landrace) were randomly allocated to the five different dietary treatments. Feed intake, body weight gain and feed conversion ratio were measured. After 98 days of feeding, all pigs were slaughtered for the evaluation of carcass and nutritional content of the organ and muscle tissues. Diet significantly affected pig growth performance. Carcass weight of pigs fed diets with BSFLM replacing FM by 50, 75 or 100% (w/w) was higher than for pigs fed control diet with 100% FM as protein source. Crude protein content of pork tissues was high (65-93% on dry-matter basis) across all dietary groups. Therefore, BSFLM can replace FM in pig feed. This is relevant for commercial pig feed production and provides for the first time a nutritional analysis of pork derived from pigs raised on BSFLM.

Edible insects are increasingly being considered as sustainable alternatives to fish and soybean meals in animal feed because of their high nutritional quality and environmental benefits. However, successful introduction of a new product to the market depends on the target user's acceptance. Thus, evaluating the potential demand of insect-based feeds would provide relevant information for policy development. The present study assessed farmers' knowledge on edible insects as feed, their acceptance of integrating insect meals in animal feeds and willingness to pay (WTP) for insect-based feed (IBF) using a contingent valuation method. A household survey was conducted among 957 randomly selected farmers including: 409 poultry, 241 fish and 307 pig farmers in four counties in Kenya. Results of the study reveal that over 70 and 80% of poultry and fish farmers, respectively, are aware that insects can be used as a feed ingredient. In addition, over 60 and 75% of poultry and fish farmers, respectively, consider insects as a good component of feed. Poultry, pig and fish farmers interviewed accepted and showed willingness to pay for IBF. Regression analysis indicated that age, gender, education, marital status, distance to feed trader, awareness of insects as feed, attitude towards insects, acceptance of insect species, availability of agricultural inputs, use of commercial feeds, availability of training and market information had a significant influence on the WTP for IBF. Therefore, increased extension services to educate famers on the nutritional benefits of insect meals in animal feeds and existing market opportunities are expected to improve farmers' attitude towards utilization and consequently enhance WTP for IBF, which in return would significantly reduce the existing pressure on conventional fishmeal feed resources. Our findings provide the first insights into the market opportunities of including insect meals in the animal feed value chain in Kenya.

Pig, poultry and fish farming are among the fastest growing agribusiness activities in East Africa, but high cost of major feed protein ingredients including fishmeal hampers profitability and growth of smallholder production. Interest in insects as an alternative nutrient source is growing. Black soldier fly (BSF) Hermetia illucens L. (Diptera: Stratiomyidae) is the most common insect species reared for animal feed. BSF larvae are able to exploit a wide variety of rearing substrates, including organic side streams, thus upgrading low-grade substrates into a high-quality protein source; BSF is not considered as a pest or vector of diseases and does not constitute a nuisance. These attributes make it an attractive insect species for mass production as sustainable and affordable feed ingredient. This thesis explores the potential of BSF as a novel feed ingredient in Kenya. The need to establish an insect-based feed sector has become important, but for insect-based feed to make a substantial contribution in substituting the conventional protein-rich fishmeal and soybean meal, large quantities of insect biomass are required, which makes insect mass rearing an inevitable step. Therefore, knowledge on sources of substrates for rearing BSF larvae, suitability of insect meal as feed ingredient, as well as acceptance and demand by end users is necessary for a sustainable insect-based feed sector. Promoting inclusive business for smallholder farmers through insect farming in an agribusiness value chain has been discussed. Farmers’ knowledge and willingness to pay for insect-based feed have been assessed. Larvae of BSF have been reared on agro-industrial by-products composed of brewers’ spent grains (BSGs), brewer’s yeast and cane molasses, their nutritional composition assessed, and have subsequently been fed to pigs. The results show that farmers are aware of insects as feed and are willing to use insect-based feed. BSGs are suitable for rearing larvae of BSF and supplementing BSGs with brewer’s yeast or molasses affects the crude protein or fat content of the larvae, respectively. Fishmeal has been replaced up to 100% with BSF larvae in feeds for growing and finishing pigs, demonstrating that these larvae are a suitable and affordable alternative to fishmeal with a beneficial return on investment, growth, carcass and nutritional quality of edible pork by-products. The study described in this thesis provides valuable insights into the suitability of combining different agro-industrial by-products for producing high-quality BSF larvae. These results are relevant to animal feed producers seeking to include insect meal in their feed formulae, to smallholder BSF farmers that either generate a circular production on-farm or sell BSF to feed millers. Finally this contributes to sustainable and economically viable livestock feeding systems.

Pig production is one of the fastest growing livestock sectors. Development of this sector is hampered by rapidly increasing costs of fishmeal (FM), which is a common protein source in animal feeds. Here, we explored the potential of substituting FM with black soldier fly larval meal (BSFLM) on growth and blood parameters of pigs as well as economic aspects. At weaning, 40 hybrid pigs, i.e., crossbreeds of purebred Large White and Landrace were randomly assigned to five iso-nitrogenous and iso-energetic dietary treatments: Control (0% BSFLM and 100% FM (T0)), and FM replaced at 25% (T25), 50% (T50), 75% (T75) and 100% (T100) with BSFLM. Average daily feed intake (ADFI), average daily gain (ADG), body weight gain (BWG) and feed conversion ratio (FCR) were calculated for the whole trial. Hematological and serum biochemical parameters, the cost&ndash, benefit ratio (CBR) and return on investment (RoI) were evaluated. No significant effect of diet type was observed on feed intake and daily weight gain. Red or white blood cell indices did not differ among diets. Pigs fed T25, T75 and T100, had lower platelet counts compared to T0 and T50. Dietary inclusion of BSFLM did not affect blood total cholesterol, triglycerides, low-density lipoprotein and high-density lipoprotein. CBR and RoI were similar for the various diets. In conclusion, BSFLM is a suitable and cost-effective alternative to fishmeal in feed for growing pigs.

Background In recent years, there has been a rapidly growing demand for readily accessible substrates for mass production of Black Soldier Fly, Hermetia illucens Linnaeus. Beer production results in various by-products that typically end up in uncontrolled dumpsites constituting pollution problems, which merits urgent attention. The present study investigated whether the 12 formulated diets composed of brewers’ spent grains (BSGs), brewers’ yeast and cane molasses can serve as substrate for H. illucens production. Methods Four different BSGs were selected and formulated into 12 diets, aiming at varying protein and net energy levels. The diets were offered to newly hatched (∼1 h old) H. illucens larvae and the influence on developmental duration, survival, wet weight, pre-oviposition time, fecundity, and longevity were compared. Results Developmental duration of the larvae (16–21 days) and pre-pupae (8–11 days) differed significantly across the different diets. The developmental duration of the pupae (8.7–9.1 days) was not affected by diet. The larval (86–99.2%), pre-pupal (71–95%), and pupal (65–91%) survival rates varied significantly between flies reared on the different diets. The pre-oviposition time was similar for flies provided with water (7–11 days) and 10% sugar solution (8–14 days) or across the different diets. The mean fecundity per female ranged from 324–787 eggs and did not differ between females provided with water or sugar solution. However, the number of eggs laid per female varied significantly across the different diets when provided with water. The longevity of starved H. illucens adults was significantly lower (5 days) compared to those provided with water (11–14 days) or sugar solution (14–15 days). Discussion The implications of these findings as part of a quality control procedure for commercial production of high-quality H. illucens larvae as an alternative protein ingredient in livestock and aquaculture feed are discussed.

Efforts to recycle organic wastes using black soldier fly (BSF) Hermetia illucens into high-nutrient biomass that constitutes a sustainable fat (biodiesel) and high-quality protein ingredient in animal feeds have recently gained momentum worldwide. However, there is little information on the most suitable rearing conditions for growth, development and survivorship of these flies, which is a prerequisite for mass production technologies. We evaluated the physiological requirements for growth and reproduction of H. illucens on two diets [spent grains supplemented with brewers' yeast (D1) and un-supplemented (D2)]. Development rates at nine constant temperatures (10-42°C) were fitted to temperature-dependent linear and non-linear day-degree models. Thereafter, life history table parameters were determined within a range of favourable temperatures. The thermal maximum (TM) estimates for larval, pre-pupal and pupal development using non-linear model ranged between 37.2 ± 0.3 and 44.0 ± 2.3°C. The non-linear and linear day-degree model estimations of lower developmental temperature threshold for larvae were 11.7 ± 0.9 and 12.3 ± 1.4°C for D1, and 10.4 ± 1.7 and 11.7 ± 3.0°C for D2, respectively. The estimated thermal constant of immature life stages development of BSF was higher for the larval stage (250±25 DD for D1 and 333±51 for D2) than the other stages evaluated. Final larval wet weight was higher on D1 compared to D2. The population growth rate was most favourable at 30-degree celsius (°C) with higher intrinsic rate of natural increase (rm = 0.127 for D1 and 0.122 for D2) and shorter doubling time (5.5 days for D1 and 5.7 days for D2) compared to the other temperatures. These results are valuable for the optimization of commercial mass rearing procedures of BSF under various environmental conditions and prediction of population dynamics patterns using computer simulation models.