BSFL has used in poultry feed as a replacement for FM and SBM. In experiments with broiler quails, Coturnix Coturnix japonica, no difference was found on productive performance, breast meat weight and yield between the experimental group in which two proportion of BSFL meal was used and control in which commercial broiler poultry feed was used.

Black soldier fly (BSF) larvae can be used to convert a number of organic waste streams into protein and fat. Resulting larvae can be used as a replacement of expensive protein sources used in poultry diet formulations, such as soybean meal (SBM) and fish meal (FM). Doing so solves two issues, potential environmental pollution by these organic waste streams while reducing pressures to increase food, and feed production. The nutrient composition of BSF larvae produced on various waste streams provide possible precursors of chemicals (protein, fat, amino acids, fatty acids, minerals and vitamins) to use as poultry feed.

CONVENTIONAL INGREDIENT IN POULTRY FEED

Soybean meal and its limitation in poultry feed utilization Soybean meal is the most important protein source used to feed farm animals representing two thirds of the total world output of protein feedstuffs, including all other major oil meals, and fish meal.

Soybean cake is a main protein source for swine and poultry in Europe. Using this protein source as animal feed is controversial due to its potentially negative environmental and social impacts (Maurer et al., 2015; Semino, Paul, Tomei, & Joensen, 2009).

As previously mentioned, calculations by the Food and Agricultural Organization of the United Nations predict the world’s population will grow to around 9 billion people by 2050 (Alexandratos and Bruinsma, 2012), resulting in a higher consumption of food from animal origin; therefore, an increased demand for protein to feed livestock is expected.

Alternative protein sources will play an important role to fill the resulting supply gap. A focus will be on sources which do not use arable land resources therefore, not competing with food crops for human nutrition (Cassidy et al., 2013).

Soybean production reached up to 210.9 million tons annually, which is slightly more than 50% of the total production of oilseed meal. Soybean is one of the widespread crop in the world, and its cultivation grew 1.4% from 2010 to 2011 (FAO, 2012; Sánchez-Muros et al., 2014).

There is no doubt SBM is high quality protein with a rich amino acid profile, high digestibility, and other nutritive benefits among the vegetable protein source available.

But SBM contains several unfavorable aspects, such as anti-nutritional factors, imbalance between the essential and nonessential amino acids, low palatability, high proportion of fiber, and non-starch polysaccharides, which limit the percentage of inclusion in the diet (Li et al., 2013; Sruamsiri and Silman, 2008).

In view of the above limitations with the use of SBM, it is necessary to use high value protein source such as protein derived from vertebrates, which has high digestibility, and having a good balance between essential and nonessential amino acids (Refstie et al., 1998, 1997; Webster et al., 1992; Webster and Goodgame‐Tiu, 1995).

Soybean cultivation requires massive quantities of land and water. Monoculture production of soybean depletes soil nutrients, resulting in the use of synthetic fertilizers and chemicals to maintain crop yield annually which could impact the environment (Castanheira and Freire, 2013; Fearnside, 2001).

Presently, soybean production for use as animal feed has increased 500% over last 40 years (FAO, 2012; Sánchez-Muros et al., 2014).

With the expected growth in the global human population over the next 40 years, the necessary increases in soy production might not be attainable (FAO, 2012; Sánchez-Muros et al., 2014).

The compositional data indicate that these BSF larval meals are good sources of protein and fat. In particular, BSF larval meal showed a similar CP content than soybean meal, which was close to meat meal, but it had a higher fat content (De Marco et al., 2015b).

The gross energy MJ/kg in dry matter (DM) of BSFL is 20-24 MJ/kg, whereas in soybean meal 16.3 which is less than BSFL.

The essential and non-essential amino acids (AA) in BSF larval meal have higher value as compared to the SBM except arginine (Barroso et al., 2014; Liu et al., 2017; Makkar et al., 2014; Ravindran et al., 2005, 1999).

Moreover, the mineral content calcium, phosphorus, potassium, sodium, magnesium, iron, manganese, zinc, copper, aluminum have greater in DM of BSFL as compared to the SMB (Liu et al., 2017; Makkar et al., 2014).

Fish meal and its limitation in poultry feed utilization

Fish meal is excellent protein source in commercial poultry, and is prime requirement for intensive control livestock farming (Olsen and Hasan, 2012). The FM obtains from the fishery production, the global total capture data in 2014 was 93.4 million tonnes, of which 81.5 million tonnes from marine waters, and 11.9 million tonnes from inland waters.

For marine fisheries production, China persisted the major producer followed by Indonesia, the United States of America and the Russian Federation (Bell et al., 2017; Kow and Liu, 2017).

However, in 2016, fish harvested from aquaculture amounted to 79.3 million tonnes, therefore, the total fisheries, and aquaculture production was 171.2 million tonnes (FAO, 2018).

The share of world fish production utilized for direct human consumption has increased significantly in recent decades, up from 67% in the 1960s to 88% in 2016, or more than 151 million tonnes, in 2016.

The remaining 21 million tonnes was destined for non-food products, of which 19.2 million tonnes was reduced to FM, and fish oil in 2016. FM prices rise significantly from 2000 to 2016, reach at peak level at US$2192.7 per tonne in 2014 and slight decrease 2031.9 in 2016 (FAO, 2018).

The FM, and fish oil are still graded considered the most nutritious, and digestible ingredients for poultry feeds. Presently the world production of FM and fish oil become stable at approximately 5 to 6 million tons per year from last fifteen year, and not expected to increase (Sánchez-Muros et al., 2014).

In spite of excellent nutritive properties the FM has advantages of other animal protein source because of the current laws forbidding the use of most MM due to the problem of food security, it makes FM the most used animal protein source (Sánchez-Muros et al., 2014).

But at the same time, we are depleting, and exploiting ocean, robbing ourselves to feed one meat source to other meat source.

Meat Meal and its limitation in poultry feed utilization

Meat meal (MM) is poultry feedstuff which is produces by the recycling of animal and poultry by-product (Boix et al., 2004). The MM is mainly dry rendered product derived from the mammalian bones, and associated tissue such as tendons, ligaments, skeleton muscle, gastrointestinal tract, lugs, and condemned livers, whereas, hair, hooves, horns, hide trimmings, blood, and stomach content are not permitted to be added to meal (Prado et al., 2007).

Variations in the proportions of these raw materials contribute to the large variations in MM quality.

The composition depending on the proportion of bone and soft tissue used in the manufacturing, the finished product is designated as MM containing 50 to 52% CP, 8.5 to 14.8% CF, 6 to 12% calcium, and 3.5 to 5% phosphorus (Olufemi and James, 2015; Miles, 2011).

Collagen is the main protein in bone, connective tissue, cartilage, tendon, and comprises no tryptophan.

In MM, 50 to 65% of total protein may be collagen. Increasing the level of bone in MM lowers the nutritive value, and the quality of its protein may vary greatly in terms of amino acid composition and digestibility.

Protein quality is also affected by the temperature used to process the MM (Miles, 2011). As a supplement to cereal-based diets, MM is of lower quality than FM or SBM.

Tryptophan is the first limiting amino acid in MM for poultry fed maize-based diets; lysine, and methionine are also limiting (Kellems and Church, 2010; Ravindran, 2013b).

Normally, no more than 10% meat, and bone meal is recommended for use in poultry diets, largely because phosphorus requirements are met at that level (Kellems and Church, 2010; Ravindran, 2013b).

BLACK SOLDIER FLY LARVAL MEAL

AS ALTERNATIVE PROTEIN SOURCE IN POULTRY FEED

BSFL has used in poultry feed as a replacement for FM and SBM (Onsongo et al., 2018; Wang and Shelomi, 2017).

In experiments with broiler quails, Coturnix Coturnix japonica, no difference was found on productive performance, breast meat weight and yield between the experimental group in which two proportion of BSFL meal was used and control in which commercial broiler poultry feed was used (Cullere et al., 2017, 2016).

BSFL meal replacement had no effect on breast meat sensory aspects and flavor perceptions, oxidative status, or cholesterol composition; and it improved the amino acid contents of the meat towards improved nutritional value (increased aspartic acid, glutamic acid, alanine, serine, tyrosine, and threonine).

However, it increased levels of the less-desirable saturated and monounsaturated fatty acids (FA) (Cullere et al., 2017).

Similar effects were found with BSFL supplementation in the diet of broiler chickens, Gallus gallusdomesticus, with the note that using defatted BSFL reduced the negative impact on fatty acid profiles.

In both cases the authors found BSFL to be a promising protein source for poultry feed (Schiavone et al., 2017), with the authors concluding “BSFL meal inclusion guaranteed satisfactory productive performances, carcass traits, and overall meat quality” (Schiavone et al., 2016).

BSFL supplementation (50%) or total replacement of soybean cake in the diets of laying hens had no impact on hen health or performance and little to no effect on the eggs themselves (Maurer et al., 2016).

BSFL are also highly palatable to poultry, with laying hens reported to seek out BSFL from feeders rather than continue to eat ad-libidum provisioned wheat–soy feeds (Wang and Shelomi, 2017).

As a component of a compound poultry feed, BSF larvae meal has been found to support better growth in chicken birds.

Chicks fed a diet containing dried BSFL (as a substitute for SBM) gained weight at a rate of chicks fed the control diet containing SBM (Makkar et al., 2014; Newton et al., 2005), suggesting higher feed conversion efficiency of diet containing the larvae meal.

Thus, BSFL are a potential partial substitution for poultry feed, providing protein. Moreover, BSFL can be reared on the manure of the same birds that consume them, simultaneously valorizing and recycling the waste (Rehman et al., 2017b).

It is therefore well established BSFL can be used to feed many vertebrates (Tomberlin et al., 2015) and can use various vertebrate wastes as a substrate, with no effects on the palatability of the BSFL-fed meats for humans and with significant implications for sustainable and lower-input agriculture in the developing world (Diener et al., 2011; Nyakeri et al., 2017).

While the potential benefits are greatest in these developing nations, BSFL and other insect feeds are expected to play larger roles over time in advanced economies, due to pledges to reduce waste among food conglomerates seeking approval from increasingly environmentally-conscious consumers and regulators, combined with the volatile prices of FM and other feed directing producers to seek alternatives (Klonick, 2017).