Effect of dietary supplementation with insect fats on growth performance, digestive efficiency and health of rabbits

Abstract

BackgroundThe present work aimed at evaluating the effect of the dietary replacement of soybean oil (S) by two types of insect fats extracted from black soldier fly larvae (H, Hermetia illucens L.) and yellow mealworm larvae (T, Tenebrio molitor L.) on growth performance, nutrient digestibility, blood parameters, intestinal morphology and health of growing rabbits.MethodsAt weaning, 200 crossbred rabbits (36 days old) were allotted to five dietary treatments (40 rabbits/group): a control diet (C) containing 1.5% of soybean oil and four experimental diets where soybean oil was partially (50%) or totally (100%) substituted by H (H50 and H100) or T (T50 and T100) fats. Total tract digestibility was evaluated on 12 rabbits per treatment. The growth trial lasted 41 d and, at slaughtering (78 days old), blood samples were collected from 15 rabbits per treatment, morphometric analyses were performed on duodenum, jejunum and ileum mucosa, and samples of liver, spleen and kidney were submitted to histological evaluation.ResultsNo difference was observed between the control and the experimental groups fed insect fats in terms of performance, morbidity, mortality and blood variables. The addition of H and T fats did not influence apparent digestibility coefficients of dry matter, protein, ether extract, fibre fractions and gross energy. Gut morphometric indices and organ histopathology were not affected by dietary inclusion of H and T fats.ConclusionsH and T fats are suitable sources of lipid in rabbit diets to replace soybean oil without any detrimental effect on growth performance, apparent digestibility, gut mucosa traits and health.Electronic supplementary materialThe online version of this article (10.1186/s40104-018-0309-2) contains supplementary material, which is available to authorized users.

Antimicrobial effects of Black Soldier Fly and Yellow Mealworm fats and their impact on gut microbiota of growing rabbits

“…Recently, insects are receiving great attention as novel alternative feed ingredients because of their excellent nutritive properties [11] and their potential effect on animal health [12,13]. It has been shown that insects have the ability to modulate the intestinal microbiota with positive effects on poultry growth, health and resistance against pathogens [13][14][15][16][17].…”

“…Lipids are a main component of insects (30-40% of the dry matter, DM) [18] and, once extracted during the insect larvae processing, they can be used as an interesting feed ingredient in animal farming [12-13; 19-24] Black soldier y (Hermetia illucens, HI) and Yellow mealworm (Tenebrio molitor, TM) fats are characterized by a different fatty acid (FA) pro le. The HI fat is rich in saturated FAs (SFA) and in medium chain FAs (MCFA), mainly lauric acid (C12:0; 48% of the total FA pro le) [12], which has an antimicrobial effect on a wide range of microbes [25]. On the other hand, the TM fat is considered as a source of n-6 poly-unsaturated FAs (PUFA), with high linoleic acid content (9% of the total FA pro le) [12].…”

“…The HI fat is rich in saturated FAs (SFA) and in medium chain FAs (MCFA), mainly lauric acid (C12:0; 48% of the total FA pro le) [12], which has an antimicrobial effect on a wide range of microbes [25]. On the other hand, the TM fat is considered as a source of n-6 poly-unsaturated FAs (PUFA), with high linoleic acid content (9% of the total FA pro le) [12]. MCFA are effectively absorbed and metabolized on the gastro-intestinal tract and known for their physiological and antibacterial effects on Gram positive bacteria [26][27][28].…”

Insect and fish by-products as sustainable alternatives to conventional animal proteins in animal nutrition

“…Overall, insects are generally rich in proteins (30-68% on dry matter, DM) with well-balanced amino acid profiles (Finke 2015;Gasco et al 2018a;Koutsos et al 2019). In addition, they result promising as a fat/ energy source (Wang and Shelomi 2017;Biasato et al 2018;Schiavone et al 2018;Gasco et al 2019b) being rich in lipids (about 10 to 30% on DM), though their fatty acid profile is highly variable. Insects can be considered also a good source of vitamins (especially vitamin B 12 ) and bioavailable minerals, particularly iron and zinc (Finke 2015;Payne et al 2016).…”

Black soldier fly from pest to ‘crown jewel’ of the insects as feed industry: an historical perspective

“…The purpose of this article is to provide some historical perspective of the black soldier fly before its recognition as a model for recycling organic waste to produce feed for aquaculture (St. Hilaire et al, 2007), poultry (Moula et al, 2017), livestock (Biasato et al, 2019;Gasco et al, 2019), and pets (Bosch et al, 2014), or use to produce bio-energy (Surendra et al, 2016), while generating organic matter (i.e. frass) that can be used as fertiliser (Setti et al, 2019;Xiao et al, 2018).…”