Influence of dietary inclusion of black soldier fly larvae protein hydrolysates on nutritional indicators and cardiac-related biomarkers of adult beagle dogs.

Protein hydrolysates derived from insects have been explored in recent years for their bioactive functionalities, namely antioxidant and antihypertensive activities, although the investigation of in vivo effects remains scarce. The present study aimed to assess the effects of dietary inclusion of black soldier fly (Hermetia illucens) larvae (BSFL) hydrolysates on nutritional status and cardiac biomarkers of adult Beagle dogs. Three complete diets were used: a control diet containing 3% shrimp hydrolysate (D_Shrimp), and two experimental diets in which the shrimp hydrolysate was replaced by BSFL hydrolysates obtained through the enzymatic hydrolysis with either ALCALASE 2.5 L (D_BSFL-A) or Corolase PP (D_BSFL-C). Two-bowl tests were performed to determine palatability by pairwise comparison between all diets. A feeding trial designed according to four 3 × 3 Latin squares with twelve adult Beagle dogs, three periods of 28 d each, and the three complete diets were performed. A cardiac evaluation was performed to all dogs before the trial. Diet digestibility, fecal characteristics and metabolites, skin and coat quality, and cardiac biomarkers were assessed at the end of each period. No significant differences were observed on first approach, first-taste, and intake ratio. Experimental diets increased organic matter (P = 0.038) and crude protein (P = 0.048) digestibility compared to control, and dry matter digestibility was greater (P = 0.048) for D_BSFL-A than D_BSFL-C. No significant differences were observed in serum levels of C-reactive protein, cardiac troponin I, and NT-proBNP among diets, but dogs fed D_BSFL-A tended to have a lower (P = 0.086) serum insulin-like growth factor 1 level compared to dogs fed D_BSFL-C. Although all echocardiographic measurements remained within normal reference ranges, experimental diets promoted a lower (P = 0.030) interventricular septum diameter in diastole compared to the control, and a lower pulmonary vein diameter was noted for D_BSFL-C compared to D_BSFL-A (P = 0.049). Also, dogs fed D_BSFL-C showed a tendency to lower blood pressure (P = 0.102), serum angiotensin converting enzyme (P = 0.092), and left atrial-to-aortic root ratio (P = 0.062) compared to dogs fed D_BSFL-A. In conclusion, diets containing BSFL hydrolysates are well accepted and digested by dogs and might influence mechanisms involved in blood pressure regulation and potentially modulate cardiac function, although further studies are warranted.