In vivo and in vitro Digestibility of an Extruded Complete Dog Food Containing Black Soldier Fly (Hermetia illucens) Larvae Meal as Protein Source

Abstract

Growing attention is being directed toward insects as a novel and sustainable source of protein for pet food. The aim of the study was to evaluate nutrient digestibility of a diet containing black soldier fly larvae as its main protein source. Moreover, the purpose of the study was to compare the traditional in vivo total collection method with the in vivo marker method and in vitro digestibility method. Two isonitrogenous and isoenergetic dry diets containing either venison meal (CTRL diet) or black soldier fly larvae meal (BSF diet) as their primary sources of proteins were fed to six adult dogs, according to a Latin square design. The digestibility of nutrients was determined using both in vivo (“total collection” and “internal marker” approaches) and in vitro methods. The two diets showed similar nutrient digestibility values for dry matter, organic matter, ether extract, ash, and phosphorus. However, a statistical trend (p = 0.066) was observed indicating greater protein digestibility in the BSF diet compared with the CTRL diet. Calcium digestibility was higher in the BSF diet compared with the CTRL diet (p = 0.018). On the contrary, fiber digestibility was lower in the insect-based diet compared with the venison diet (p < 0.001). There was no difference between total collection and internal marker methods in the assessment of in vivo digestibility for any of the nutrients considered. The in vitro digestibility values for dry matter, organic matter, and crude protein, as well as the estimated in vivo digestibility of organic matter and crude protein by the means of the predictive equation, were aligned with the in vivo results, although in vitro estimations were consistently higher compared with those obtained by in vivo analysis. Digestibility analysis of a dog food containing insect meal as the sole source of protein (36.5% inclusion) showed promising results in terms of it presenting similar values as a meat-based diet, indicating its suitability as a sustainable protein source for pet food. Moreover, the study showed that both the in vivo marker method and the in vitro method could be possible alternatives to the traditional total collection method in digestibility trials.

Insect Larvae Meal (Hermetia illucens) as a Sustainable Protein Source of Canine Food and Its Impacts on Nutrient Digestibility and Fecal Quality

“…Organic matter digestibility in our study was similar for dogs offered either PM- or BSFL meal-based diets (83.6%). A similar result was obtained by Penazzi et al [ 38 ], where organic matter digestibility was similar in dogs fed the control (processed deer protein source up to 40% as fed) and BSFL meal (36.5% as fed). In vitro organic matter digestibility of house crickets was reported to be 88% as observed by Bosch et al [ 6 ], which was similar to that of PM (85.8%).…”

Possibility of Using House Cricket (Acheta domesticus) or Mulberry Silkworm (Bombyx mori) Pupae Meal to Replace Poultry Meal in Canine Diets Based on Health and Nutrient Digestibility

“…The digestibility of dry matter, organic matter, and fat is not influenced by the use of black soldier fly larvae [7][8][9][10][11], yellow mealworm [7], or tropical house cricket [12] in canine feed, which agreed with this study. Therefore, dogs can be fed these insects without problems in these digestibility parameters.…”

“…Differences in protein source (poultry meal, venison, or lamb), raw material quality, formulation, and animals could be an important factor influencing the different values of crude protein digestibility. Moreover, different crude protein proportions in the control diet were set at 18.1-32.0%DM in other studies [8,9,11,12,20], whereas in this study, the crude protein content was 23.5%DM. Therefore, from the crude protein digestibility lower than 80% found in this study, one still cannot conclude that AD and BM are not a good quality protein source because the crude protein digestibility was similar to the control diet using poultry meal.…”

“…The in vitro digestibility and fermentation of crude house cricket protein is close to those of poultry meal and soybean meal in dogs [6]. The apparent total tract digestibility of crude protein by dogs consuming diets containing black soldier fly larvae [7][8][9][10][11], yellow mealworm [7], or tropical house cricket [12] was 77.1-87.2%, 83.6%, and 82.1-86.0%, respectively. However, the apparent crude protein digestibilities of AD (75.4-76.9%) and BM (77.3-78.0%) in this study were lower than seen in other studies, but similar to the control diets (72.8%).…”

“…Therefore, insects have potential as alternative protein sources for animals, particularly dogs. Based on several study reports, dogs have been shown to be able to consume diets containing black soldier fly (Hermetia illucens) larvae [6][7][8][9][10][11], tropical house cricket (Gryllodes sigillatus) [12], housefly (Musca domestica) larvae, lesser mealworm (Alphitobius diaperinus) [6], and yellow mealworm (Tenebrio molitor) [6,7] without adverse effects on health or nutrient digestibility, even if used as almost total replacements for common protein sources [6]. House cricket (Acheta domesticus: AD) and mulberry silkworm (Bombyx mori: BM) pupae are other potential insects able to be produced on a large scale.…”