| Hermetia illucens L. larvae can convert organic waste such as food waste. They produce insect protein, which can be used for livestock and aquaculture feed. Meanwhile, their frass serves as high-quality organic fertilizer. Probiotic microbes play a vital role in the processing of organic waste by the black soldier fly larvae (BSFL). However, the role of lactic acid bacteria in promoting the efficient processing of organic waste by black soldier fly had rarely been studied. This study focused on the black soldier fly larvae and evaluated the impact of different lactic acid bacteria strains added to the artificial feed system for these larvae. The goal was to identify lactic acid bacteria that enhance larval survival rate, conversion efficiency, and protein accumulation, designating them as probiotic lactic acid bacteria. By adding lactic acid bacteria to the black soldier fly larvae’s artificial feed system, three candidate probiotic lactic acid bacteria strains (L4, L7, and L8) were preliminarily screened. After morphological observation, physiological and biochemical identification, and 16S rDNA sequence analysis, L4 was identified as Levilactobacillus brevis, L7 as Levilactobacillus cerevisiae, and L8 as Lactiplantibacillus plantarum. Compared to the control group, the addition of probiotic lactobacilli L4, L7, and L8 significantly increased the fresh weight of black soldier fly larvae by 5.93%, 6.41%, and 9.43%, respectively. Additionally, the conversion rate of the larvae improved by 8.01%, 7.18%, and 13.60%, while the reduction in feed material was enhanced by 3.47%, 4.75%, and 6.28%. Importantly, L4, L7, and L8 demonstrated a significant promotion effect on protein accumulation in black soldier fly larvae. Compared to the control group, the crude protein content of the larvae increased significantly by 5.14%, 3.13%, and 4.70%, respectively. Additionally, the total protein yield of the larvae increased significantly by 14.40%, 14.84%, and 17.63%. In summary, this study screened, identified, and evaluated lactic acid bacteria with probiotic effects on black soldier fly larvae. These lactic acid bacteria not only enhance the larvae’s conversion rate of artificial feed, resulting in greater biomass, but also promote protein accumulation in the larvae, leading to higher-quality insect protein. The research findings are of significant importance in revealing the synergistic metabolic mechanisms between black soldier fly larvae and gut microbiota, and they hold great potential for large-scale conversion of organic waste by black soldier fly larvae. |
