Do, Sungho (2021) Black soldier fly larvae as an alternative protein source for canine and feline diets. Dissertation at Animal Sciences, University of Illinois at Urbana-Champaign https://www.ideals.illinois.edu/items/124834
Abstract: The overall objective of this dissertation was to evaluate the nutrient composition of BSFL, its amino acid (AA) digestibilities using a precision-fed cecectomized rooster model, and its effects on palatability, apparent total tract digestibility (ATTD), fecal characteristics, and skin and coat health markers of healthy adult cats. Our first aim was to determine the effects of harvest age on nutrient and AA digestibility and digestible indispensable amino acid score (DIAAS)-like values of BSFL using the precision-fed cecectomized rooster assay. The BSFL were harvested at six different ages (days after hatch; day 0, 11, 14, 18, 23, and 29). Our second aim was to evaluate the effects of BSFL dietary calcium form and concentration on nutrient composition, nutrient and AA digestibilities, and DIAAS-like values for BSFL using the precision-fed cecectomized rooster assay. Calcium chloride (CaCl2) and calcium carbonate (CaCO3) were used to raise BSFL at different concentrations (1.2% of CaCl2, 1.2% of CaCO3, 0.75% of CaCO3, and 0.6% of CaCl2 and CaCO3). Our third aim was to determine palatability and ATTD of BSFL-containing canned diets, fecal characteristics, and skin and coat health markers of healthy adult cats consuming them. Cats were fed the canned diets formulated with poultry by-product meal (PBPM), BSFL meal, whole BSFL, and BSFL oil. In our first aim, we determined that all harvest ages of BSFL were contained high-quality protein that were well digested, but AA digestibilities were highest at days 14, 18, and 23. Threonine, Met, Cys, and Arg often were the first-limiting AA of BSFL based on DIAAS-like reference values for dogs and cats. In our second aim, we determined that nutrient and AA digestibilities were high (81% to 96% digestibilities), but not different among BSFL fed different calcium sources and concentrations. Aromatic AA (Phe + Tyr) and sulfur-containing AA (Met + Cys) often were the first-limiting AA based on DIAAS-like reference values for dogs and cats. In our third aim, we reported that the intake ratios were higher in cats fed canned diets containing BSFL meal (1.93:1), whole BSFL (2.03:1), and BSFL oil (1.57:1) compared with a poultry-based control diet. Fecal pH and scores and caloric intake were not different (P > 0.05) among diets, but fecal output (as-is, DM, and kcal/d) was highest (P < 0.05) for cats fed BSFL meal compared with those fed BSFL oil. The ATTD of acid-hydrolyzed fat (AHF) was not different among treatments, while DM ATTD was greater (P < 0.05) for cats fed the BSFL oil diet than for those fed the BSFL meal diet. The ATTD of OM by cats fed control or BSFL oil diets was greater (P < 0.05) than for those fed the BSFL meal or BSFL whole diets. For crude protein (CP) and energy, ATTD was greatest (P < 0.05) for cats fed the BSFL oil diet and lowest for those fed the BSFL meal diet. Skin and coat health markers, including skin transepidermal water loss (TEWL), skin hydration status, hair imaging score, and skin and coat hair scores were not affected (P > 0.05) by treatments. Similarly, hematology and a delayed-type hypersensitivity (DTH) response to saline, phytohaemagglutinin (PHA), and concanavalin A (CONA) showed no differences (P > 0.05) among diets. A select serum metabolites were affected by diet (P < 0.05), but remained within reference ranges. This research provided information on the potential for using BSFL in pet foods. Based on our results, the suggested harvest age of BSFL ranges between 14 and 23 days because these ages provide the highest protein quality. Black soldier fly larvae raised with calcium chloride and calcium carbonate accumulate more calcium, but protein quality was similar. Finally, BSFL-derived ingredients hold strong potential for use in pet foods, whether it is included in extruded or canned foods.