PS13-14. Extracts of Black Soldier Fly Frass for Use in Neonatal Calves.

Abstract The immune system of a newborn dairy calf can be considered quite immature compared to that of many other animals due to varying management practices. This immaturity increases their susceptibility to many detrimental early-life diseases, including the likes of bacterial-induced diarrhea. Preliminary research at West Virginia University suggested that early-life consumption of Black Soldier Fly frass (BSFF; used growth media from the rearing of BSF [Enviroflight™]) by calves (day 0 - day 60 of life) may decrease challenges to their immune system by reducing early bacterial-induced gastrointestinal sickness. In this preliminary study, inconsistent dry feed intake, as commonly seen in neonatal calves learning to eat dry feed, limited the full interpretation of data (unreported), but observationally, calves consuming greater BSFF early in life may have suffered less bacterial-induced diarrhea. Solubilization of BSFF or BSFF components would allow researchers to better deliver the potential benefits of BSFF earlier and more consistently and quantify its effects on each calf through incorporation into a liquid milk replacer. In the following study, the objective was to partially solubilize random samples of a single-source BSFF with solvents chemically resembling the normal physiological liquid conditions of the calf’s gastrointestinal tract. Solvents used were distilled water and artificial saliva at pH 4.0, 5.0, and 6.0, respectively, and unmodified physiological saline (pH 5.6), all at 37 °C. Solvents (20 ml) were mixed with BSFF (4 g) or used without BSFF in quadruplicate and incubated for 18 hours, then the filtrate was collected under vacuum. The extraction procedure was conducted twice (R1 and R2), with the filtrates used to determine the solubility of BSFF. Effects of R1 extracts on in-vitro microbial digestion of soybean meal (SBM) and physical characteristics (settling of solids over time) of R2 extract incorporation in liquid milk replacer were determined. All data were subjected to statistical analysis via the program R ® and tested for normality and differences due to solvent and or solvent pH. Solvent type was uniform in the extraction (P > 0.05) of BSFF, extracting on average 21%. Solvent-corrected in vitro digestibility of SBM did not differ by solvent type (P > 0.05; averaged 70%). However, extracts of BSFF reduced (P < 0.05) digestibility by 11% while having no measurable effects on the physical characteristics of the liquid milk replacer. These data suggest that BSFF can impact microbial action. The solubilization of frass constituents in a physiological medium and their incorporation in milk-replacer-based diets hold promise in determining potential nutraceutical uses in dairy calf production.