Substitution of soy components - Does feeding hens with insect-based diets impair performance?

Summary

Soybean meal and oil are major protein and fat sources in diets for poultry. However, their use in animal feeding is controversially discussed due to potentially negative environmental and social impacts. In response, an intensive search is ongoing looking for dietary protein sources which are more sustainable and are also not competing with human food production. Among the alternative feeds discussed, there is a great interest in integrating insects into livestock nutrition as a replacement for soybean. Still the research on feeding value of insect protein meal and fat of larvae grown on different substrates is scarcer. Among the insects, the greatest potential is seen in the larvae of the Black Soldier Fly (BSF). So far, studies concentrated only on the defatted larval meal whereas the large amount of the larvae fat is only used for industrial purpose. Therefore, the aim of the present study was to investigate the possibility to replace soybean cake and oil in the organic feed of laying hens by meal and oil from larvae reared on different substrates. For this purpose 50 Lohmann Brown Classic hens, being 29 weeks old, were allocated to five dietary treatments in a randomized design. The diets differed in the ingredients used as main protein and fat sources. The control diet contained soybean cake and soybean oil while the four experimental diets were based on different defatted BSF larvae meal and fat sources. Both BFS batches were reared on preconsumer food waste, but the larval materials still largely differed because of differently intensive fat removal and refining techniques applied. The laying hens were housed individually in enriched 80 x 80 x 80 cm cages under controlled temperature, light and humidity conditions. Feed intake, laying performances and egg weight were determined daily and the hens were weighed once per week within a period of 26 days. Feed intake, body weight and laying performance did not differ significantly between the five treatments. There were diet effects on egg weight, egg mass and feed conversion efficiency (P < 0.05). Egg weight and egg mass were most favorable with the diet containing the protein meal of the larvae intensively defatted and soybean oil not being replaced by larval fat.
The feed intake of all groups was within the range recommended and as expected for hens of this age and breed. The results indicate that the insect meals and fats were well palatable and consequently the insect-based materials showed a high potential for their implementation in laying hen production. In order to underline the results of this experiment, various parameters as the egg quality or feed digestibility are currently under investigation.