Palatability and apparent total tract macronutrient digestibility of retorted black soldier fly larvae-containing diets and their effects on the fecal characteristics of cats consuming them

Abstract

There is growing interest in using black soldier fly larvae (BSFL) due to its supposed sustainability and nutritional qualities. Because little research has been conducted to evaluate the use of BSFL in cats, our objective was to determine the palatability and apparent total tract macronutrient digestibility (ATTD) of BSFL-containing canned diets and the fecal characteristics of healthy adult cats consuming them. First, three palatability tests were conducted to compare the following diets: 1) diet with poultry byproduct meal (PBPM) and chicken serving as the primary protein sources (control) vs. diet with BSFL meal replacing PBPM (BSFL meal); 2) control vs. diet with whole BSFL replacing some PBPM and poultry fat (BSFL whole); and 3) control vs. diet with BSFL oil replacing poultry fat (BSFL oil). All diets were formulated to meet Association of American Feed Control Officials nutrient profiles for adult cats and were produced using a still retort. A paired t-test was conducted to analyze data from each palatability test, with a higher (P<0.05) consumption ratio being observed for BSFL meal (1.93:1), BSFL whole (2.03:1), and BSFL oil (1.57:1). Second, 32 adult cats (20 females; 12 males; BW: 4.19 ± 0.55 kg; age: 3.3 ± 0.38 yr) were used in a completely randomized design study composed of a 21-d baseline period and a 70-d experimental period. Cats consumed the control diet during the baseline and were then allotted to 1 of 4 experimental diets (n=8/group): 1) control, 2) BSFL meal, 3) whole BSFL, and 4) BSFL oil. Fecal samples were collected after baseline and experimental periods for ATTD and fecal characteristic analysis. Fecal output was higher (P<0.05) and fecal dry matter percentage was lower (P<0.05) in cats fed BSFL meal than those fed BSFL oil. Organic matter, crude protein (CP), and energy ATTD were lower (P<0.05) in cats fed BSFL meal than those fed BSFL oil or control. CP and energy ATTD were lower (P<0.05) in cats fed BSFL whole than those fed BSFL oil. A few serum metabolites were affected by diet (P<0.05) but remained within reference ranges. Hematology was not affected by diet (P>0.05). Overall, our results suggest that BSFL-containing diets are palatable and do not negatively affect fecal characteristics or serum chemistry but may have slightly lower nutrient digestibilities in adult cats.

Effects of black soldier fly larvae as protein or fat sources on apparent nutrient digestibility, fecal microbiota, and metabolic profiles in beagle dogs

“…In contrast, our findings suggested that 20% DBP reduced the apparent CP and OM digestibility, while 8% BF had no effect on apparent nutrient digestibility. Similar to 20% DBP, previous studies in beagle dogs and cats showed that feeding 20% or 5% BSFL also decreased the apparent CP digestibility (Kröger et al, 2020;Do et al, 2022). Moreover, several studies of BSFL in economic animals (Cullere et al, 2016;Hartinger et al, 2021) and cricket meal in beagle dogs (Kilburn et al, 2020) yielded similar results.…”

The Effect of Dietary Protein Hydrolysate from Black Soldier Fly Larvae and Schizochytrium on Palatability, Nutrient Metabolites and Health Status in Beagle Dogs

“…In addition, compared with the CON diet, diets with added levels of 5%, 10%, and 15% BSFPs had significantly improved fecal scores and decreased ratios of diarrhea, and 15% BSFPs was more efficient among the treatments. The dietary treatments involving the inclusion of BSFL meal, whole BSFL, and BSFL oil displayed a significant tendency to improve fecal score for cats [ 5 ], and having 4% and 8% BSFL supplemented in their diets significantly reduced the incidences of diarrhea induced by enterotoxigenic Escherichia coli K88 in weaned piglets [ 23 ]. In addition, an early study found that DHA added to infant formula decreased infant diarrhea [ 24 ], and the dietary intake schizochytrium, rich in DHA, showed the same effect: when supplemented at 20 g/d, schizochytrium significantly reduced the diarrhea frequency caused by Escherichia coli K99 in pre-weaning dairy calves [ 25 ].…”

“…As a recent example, black soldier fly larvae (BSFL) have the huge potential to be a novel substitute in the market, especially in the pet market, because of their unique nutritional composition, including their high protein content, abundant amino acid composition, lauric acid, and essential minerals and vitamins [ 2 , 3 ]. Some studies have demonstrated that a BSFL-meal-supplemented diet had no negative influence on body health and was readily accepted by dogs [ 4 ], and the inclusion of BSFL in a cat diet was found to be more palatable and did not negatively affect fecal characteristics or blood biochemistry [ 5 ]. Moreover, hydrolysate showed more effective absorption and function due to a higher rate of pure protein and free amino acids and lower allergenicity compared with crude protein [ 6 , 7 ].…”

Influence of a Mixture of Protein Hydrolysate from Black Soldier Fly Larvae and Schizochytrium on Palatability, Plasma Biochemistry, and Antioxidative and Anti-Inflammatory Capacity in Cat Diets

“…In our palatability test, cats showed more affection and preference for the diets with supplementing inclusion of different levels of BSFPs by enhancing the first sniff, the first bite, and the feed intake compared with the CON diet. As a novel insect protein resource, research reported that the dietary supplementation of BSFP significantly promoted palatability for cats [ 65 ], and many works showed that protein hydrolysates are the most popular palatability enhancers in cat diets because of their high short peptide and free amino acid content [ 66 ]. Furthermore, the diet supplementing 0.4% schizochytrium positively improved the first choice and intake ratio for dogs, which showed evidence that palatability can be enhanced with high total concentrations of fatty acids [ 19 ].…”