Modulating the Fatty Acid Profiles of Hermetia illucens Larvae Fats by Dietary Enrichment with Different Oilseeds: A Sustainable Way for Future Use in Feed and Food

Assessing Substrate Utilization and Bioconversion Efficiency of Black Soldier Fly (Hermetia illucens) Larvae: Effect of Diet Composition on Growth and Development Temperature

Black soldier fly larvae (BSFL) can utilize food by-products or residues for growth, benefiting farm animal's diets' production sustainability. The experiment aimed to assess the effect of different substrate compositions on larval growth, chemical composition, and substrate temperature. BSFL were allocated to one of the four diets (control, vegetable, carnivorous, and omnivorous) for the entire experiment (8 days). The temperature was measured twice daily using a thermal-imaging camera, and the accumulated degree hours (ADH) was calculated. The results showed that the larvae fed the vegetable diet exhibited a significantly reduced growth performance, with a biomass reduction of 26.3% compared to the control diet; furthermore, vegetable-fed larvae showed a lower dry matter content (-30% compared to the average of other diets) due to lower fat content (-65% compared to average of other diets). The nutritional composition of larvae fed an omnivorous diet was similar to larvae fed a high-quality substrate diet (control diet-chicken feed), indicating that the omnivorous diet could be an ideal solution for rearing BSFL larvae; however, the current European legislation prohibits the use of animal meal. The study also revealed that substrate temperatures did not have a discernible influence on larval growth, further emphasizing the importance of diet in BSFL rearing strategies.

Quality Characteristics of Black Soldier Flies Produced by Different Substrates

Black soldier fly (BSF; Hermetia illucens) has a high capacity for amino acids and fatty acid accumulation. This study was conducted to assess the effectiveness of tofu by-products, food waste, and vegetables for BSF growth and conversion efficiency. BSFs under tofu by-product treatments showed the greatest weight at d 12 and the harvest period. Moreover, BSF larval weight was greater in the food waste treatment compared with the vegetable treatment at d 12 and harvest. The larva yield result was greater in the vegetable treatment compared with the tofu by-product. The bioconversion rate was higher in the tofu by-product treatment compared with the food waste and vegetable treatments. The protein conversion rate and lipid conversion rate were the highest in the vegetable treatment. The protein yield and lipid yield were greatest in the tofu by-product treatment. The lauric acid content was increased in BSFs fed tofu by-products compared with the food waste treatment. The concentration of C16:1 was the highest in the tofu by-product treatment. The content of oleic acid and α-linolenic acid was higher in BSFs fed tofu by-products compared with the vegetable treatment. In conclusion, the tofu by-products show benefits for larval growth and nutrient accumulation, which can improve larval quality for livestock feed ingredients.

Fat Quality Impacts the Effect of a High-Fat Diet on the Fatty Acid Profile, Life History Traits and Gene Expression in Drosophila melanogaster

Feeding a high-fat diet (HFD) has been shown to alter phenotypic and metabolic parameters in Drosophila melanogaster. However, the impact of fat quantity and quality remains uncertain. We first used butterfat (BF) as an example to investigate the effects of increasing dietary fat content (3-12%) on male and female fruit flies. Although body weight and body composition were not altered by any BF concentration, health parameters, such as lifespan, fecundity and larval development, were negatively affected in a dose-dependent manner. When fruit flies were fed various 12% HFDs (BF, sunflower oil, olive oil, linseed oil, fish oil), their fatty acid profiles shifted according to the dietary fat qualities. Moreover, fat quality was found to determine the effect size of the response to an HFD for traits, such as lifespan, climbing activity, or fertility. Consistently, we also found a highly fat quality-specific transcriptional response to three exemplary HFD qualities with a small overlap of only 30 differentially expressed genes associated with the immune/stress response and fatty acid metabolism. In conclusion, our data indicate that not only the fat content but also the fat quality is a crucial factor in terms of life-history traits when applying an HFD in D. melanogaster.

Improvements in Performance of Nursery Pigs Provided with Supplemental Oil Derived from Black Soldier Fly (Hermetia illucens) Larvae

The current study evaluated the impact of increasing levels of supplemental black soldier fly larvae (BSFL) oil, a novel and sustainable feed ingredient, on growth performance and blood chemistry indices in nursery pigs. Pigs were weaned at 21 days of age (n = 192; body weight = 6.9 ± 0.15 kg) and randomly allotted within sex and body weight to 1 of 4 dietary treatments, using 48 pens (4 pigs/pen). Treatments contained 0, 2, 4, or 6% supplemental BSFL oil, replacing equivalent quantities of corn oil. A 3-phase feeding program was used with 14, 11, and 15 days for phase 1 to 3, respectively. Supplementation of BSFL oil linearly (p ≤ 0.052) improved pig body weight and daily gain throughout the study and overall. No differences were observed in feed intake; however, feed efficiency was linearly improved with BSFL oil supplementation for phase 1 and 2 (p < 0.05). Serum cholesterol increased linearly (p = 0.002) and platelet count tended to increase linearly (p = 0.082) with increasing BSFL oil. No other differences were detected in blood chemistry and all results were within normal ranges. In conclusion, BSFL oil is a valuable, energy-dense feed ingredient that can promote growth performance of nursery pigs.