Utilization of Tenebrio molitor Larvae Reared with Different Substrates as Feed Ingredients in Growing Pigs

SIMPLE SUMMARY: The procurement of adequate feed resources is one of the most important challenges for the animal industry worldwide. While the need for feeds rich in protein is constantly increasing, their production cannot readily keep up. Consequently, it is necessary to identify and develop new feeding strategies and feed ingredients, such as insect meals, to overcome this challenge in a sustainable way. In the present study, Tenebrio molitor larvae that were fed on either a standard substrate or enriched with aromatic plant material were used as feed ingredients for growing pigs. A total of 36 weaned pigs (34 days old) were allocated to three groups of 12 pigs each and fed for 42 days either a conventional feed (group A) or two feeds in which the larvae meals were included at 10% (groups B and C, respectively). The three groups had similar growth and feed consumption rates. Fecal samples were analyzed, and the results showed that some important bacterial families were found in different populations. Blood analysis showed that the insect supplementation modified total cholesterol but not the rest of the parameters. Meat cuts had different enumerations of microbial populations, higher amounts of total phenols, and different fatty acid profiles, whereas they were similar in their proximate analysis and color. ABSTRACT: The procurement of adequate feed resources is one of the most important challenges for the animal industry worldwide. While the need for feeds rich in protein is constantly increasing, their production cannot readily keep up. Consequently, to overcome this challenge in a sustainable way, it is necessary to identify and develop new feeding strategies and feed ingredients, such as insect meals. In the present study, Tenebrio molitor larvae that were reared on two different substrates (standard and enriched with medicinal aromatic plant material) were used as feed ingredients for growing pigs. A total of 36 weaned pigs (34 days old) were randomly allocated to three treatment groups and fed either the control diet (A) or diets supplemented at 10% with one of the two insect meals (B and C). At the end of the trial (42 days), blood, feces, and meat samples were collected for analysis. The insect meal supplementation did not affect (p > 0.05) overall performance but significantly modified (p < 0.001) the fecal microflora balance and the blood cholesterol (p < 0.001), while the rest of the blood parameters tested were not affected. Moreover, this dietary supplementation significantly affected some microbial populations (p < 0.001), improved the total phenolic content (p < 0.05), and the fatty acid profile (p < 0.001) of the meat cuts, but did not affect (p > 0.05) meat color or proximate composition. Further research is needed to evaluate the different types and levels of inclusion of insect meals in pig nutrition.