|Tuesday, November 24|
Yeasts as a supplement in diets diets fed to mealworms (Tenebrio molitor)
* Louise Hénault-ethier, Université Laval/TriCycle, Canada
Alexis Fortin, École de Technologie Supérieure/TriCycle
Didier Marquis, Concordia University/TriCycle
Étienne Normandin, Université de Montréal IRBV/TriCycle
Myriam Tourancheau, Lallemand
Marie-Hélène Deschamps, Université Laval
Grant W. Vandenberg, Université Laval
Yeasts are eukaryotic, single-celled fungal microorganisms, encompassing some 1500 species. Traditionally used in wine, beer and bread production, they are also used in raising sterile fruit flies (Drosophila sp.) to control spoiling, and increasingly used as nutritional supplements in the food industry and in livestock feed. Brewer’s yeast alone was found to be insufficient to sustain growth in mealworn (T. molitor, but an addition of up to 5% brewer’s yeast powder is commonly used to supplement diets. As a probiotic, yeasts supplement in diets is an interesting way to boost the immune system and growth performance of insects. However, compared to traditional insects farming techniques which use nutritionally balanced cereal meals (commonly poultry feed with added vitamins and minerals), the use of agri-food by-products is often constrained by availability of waste. Our studies aims to optimize mealworms by-products diets obtained from circular-economy loops in Montreal Canada (spent brewer’s grain, off-spec cocoa beans, spent mycelium, fruit and vegetable pulp, grain milling residuals) in conducting small scale feed screening trials. Twenty-one treatments containing 5g of various feed (5 replicates) and 10 young larvae (5 mg) were monitored for growth over 89 days. Our experiments have shown that feeding mealworms with local by-products results in lower insect growth and final yields compared to commercial poultry feeds. Supplementation with yellow pea, lactoserum or hemp seeds to formulate iso-proteinic diets equivalent to commercial feeds resulted in stunted growth. The addition of B-vitamin complex by supplementing wheat bran or by-products diets with yeast flakes (5% of feed mass based on dry weight) also increased growth performance in mealworms. Using the above-mentioned experimental design (i.e., 5% dry weight yeasts supplementation), we are now testing if yeast species (Torula sp. vs Saccharomyces cerevisiae) and status (active, inactive, extracts) as well as ten types of commercially available yeasts (Lallemand, Québec, Canada) and two residual brewer’s yeasts can increase growth performance of mealworms. Our work should help to balance insect diets when fed on local by-products and thus, enabling urban circular economy initiative.
Genetic variation in qualitative and quantitative lipid content among three European strains of housefly larvae reared at different temperatures
* Francesco Boatta, Vrije Universiteit Amsterdam, Netherlands
Walter Jansen, Amusca B.V.
Leo Beukeboom, University of Groningen
Jacintha Ellers, Vrije Universiteit Amsterdam
There is a growing interest in the use of insect larvae as an alternative source of proteins for the livestock sector. A species which has so far been underappreciated for its application as feed is the common housefly, Musca domestica. Differences in lipid accumulation may occur between strains derived from different regions, due to the cosmopolitan distribution and phenotypic plasticity of the common housefly. Moreover, strains may differ in the lipid composition depending on rearing temperature as a result of climate adaptation. In this study we characterized the qualitative and quantitative lipid profile of the late developmental stages (third instar) of housefly larvae originated from three European locations (IT, SP, and NL) and reared at two different temperatures (25 and 35°C) to identify a strain with favorable lipid accumulation and lipid composition characteristics. The results of this study provide insight into the variation in lipid metabolism in the common housefly and its adaptation to high temperatures.
Fecundity and larval growth of Tenebrio molitor reared on differently composed diets of similar nutritional composition
* Somaya Naser El Deen, PhD "Environment, Resources and Sustainable Development", Parthenope university of Naples, Italy
Vincenzo Verrastro, CIHEAM-IAMB Mediterranean Agronomic Institute of Bari
Flutura Lamaj, CIHEAM-IAMB Mediterranean Agronomic Institute of Bari
Lina Al Bitar, Parthenope university of Naples - CIHEAM-IAMB Mediterranean Agronomic Institute of Bari
Ferdinando Baldacchino, Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA)
The artificial diet of Tenebrio molitor (L) has been a focal point of many studies that aimed to design the best diet combination. Recent studies have been focusing on the use of by-products and their efficiency as diets for T. molitor rearing. The rearing was successful on a wide range of by-products-based diets. Feed has a profound impact on the lifespan, growth performance, fecundity and nutritional composition of insects like T. molitor. Fecundity is one of the traits that are highly influenced by the diet's composition, especially by the macronutrients. This work aims to study the effect of 8 different diets on the weight and fecundity of females and on their progeny weight: larval weight. Wheat bran, brewer's yeast, spent grain and bread remains were used to make up the diets that were composed of a different inclusion percentage of each by-product. All the diets had narrow range of differences in nutritional composition, mainly macronutrients, although different by-product types. The diets were designed in a way to avoid the effect of different nutritional compositions and study the effect of the by-products type only. Results showed that the difference in female's weight during the egg-laying period under different rearing diets, was not significant. Moreover, the female's fecundity which is measured by the number of larvae, showed no significant difference between the different diets. However, the average larval weight was significantly higher for larvae reared on 2 diets; one composed of wheat bran and brewer's yeast and the second composed of wheat bran, brewer's yeast and spent grain. The mentioned diets although composed of different by-products, have the same amount of protein and carbohydrates. These results prove that the type of by-products included in the experimental diets affects less the performance of T. molitor compared to the nutritional composition.
Effect of temperature on life-history parameters and production performances of the common housefly, Musca domestica
* Ljubinka Francuski, University of Groningen, Netherlands
Walter Jansen, Amusca B.V
Leo W. Beukeboom, University of Groningen
Musca domestica, the common housefly, is increasingly considered as a new, alternative protein source for animal nutrition and biowaste conversion. Easy rearing requirements and the ability of housefly larvae to grow on many different substrates make them useful to turn waste (e.g. manure) into a valuable biomass. Still, industrialization of housefly faces numerous challenges and both fundamental (understanding of housefly biology) and applied (improvements on housefly production method) research is needed. We investigated life-history traits relevant for mass rearing in three European housefly strains (originated from Spain, Italy and The Netherlands) at two temperatures, 25°C and 32°C. All three strains responded to 32°C with shortened duration of preoviposition period, laying phase and overall longevity. Moreover, wing/body size, lifetime egg production, mating activity and sperm quantity and viability declined at higher temperature. In contrast, number of clutches laid per female, hatchability, percentage of pupation, adult emergence rate and wing shape were unaffected by temperature. Although females laid on average 20% fewer eggs at 32°C, the overall efficiency of the rearing process was increased. The combination of shorter sexual maturation period and higher daily egg-laying rate resulted in reaching 50% of total egg production in only six days at 32°C, compared to 13-14 days at 25°C. Our results point at beneficial effects on production performances of M. domestica at higher than 25°C and indicate that 32°C is well suited for efficient housefly rearing.
Nutritional composition and quality of dried earthworms (Lumbricidae) powder
* Ilga Gedrovica, Latvia University of Life Sciences and Technologies, Latvia
Earthworms (Lumbricidae) could also be used as alternative protein source. Powder made from dried earthworms is nutrient-rich food and could be an excellent food for human food also as ingredient for food product production in the future. The protein content of earthworms powder is 74.1 g 100g-1 and contain all essential amino acids.