Black soldier fly larvae used for environmental enrichment purposes: Can they affect the growth, slaughter performance, and blood chemistry of medium-growing chickens?

Abstract

IntroductionThis research has been aimed at evaluating the effects of live black soldier fly larvae (BSFL) (Hermetia illucens) on the growth, slaughtering performance, and blood parameters of medium-growing chickens.MethodsA total of 240, 28-day-old, Label Rouge Naked Neck chickens were allotted to four experimental groups, according to the gender (males-females) and to the absence (control group, C) or presence (larvae group, L) of a dietary supplementation with 10% live BSFL, on the basis of the expected average daily feed intake (ADFI) (6 replicates/diet, 10 chickens/replicate). The birds were weighed weekly, and the feed consumption was recorded to calculate the average live weight, feed conversion ratio (FCR), average daily gain (ADG), and the ADFI. At 82 days of age, 2 birds/replicate (12 birds/diet) were selected and slaughtered. The blood samples were collected, and the carcass traits (carcass, breast, thigh, and organ weights and yields) were assessed.Results and discussionsOverall, the administered live BSFL did not impair the growth and slaughtering performance, or the blood traits, while the C females showed a better FCR than the treated ones (P < 0.05). The live BSFL consumption time was longer for the females than for the males (P < 0.001). The weight of the immune organs (spleen and bursa of Fabricius) increased as the live BSFL supplementation increased (P < 0.05). Furthermore, the provision of live BSFL reduced the gamma glutamyl transferase (GGT, U/l) activity content in the blood (P < 0.05). Finally, both the leukocytes (%) and the monocytes (%) were more abundant in the C groups than in the larvae ones (P < 0.05 and P < 0.01, respectively). In short, the supplementation of live BSFL can be used successfully as an environmental enrichment, without affecting the growth performance of male birds. Furthermore, the immune organ activity could be enhanced by the provision of live BSFL.

Does the provision of live black soldier fly and yellow mealworm larvae improve Muscovy duck welfare?

“…Partially in agreement with the present trial, Bellezza Oddon et al [ 18 ] observed a similar overall FCR between broilers fed live BSF larvae and control birds, while they recorded a significant reduction in the overall FCR detected in broiler chickens fed live YM larvae [ 18 ]. The results of the present trial are also in line with the results reported by Bongiorno et al [ 17 ] for Label Necked Neck chickens fed BSF live larvae provided at 10% of the expected ADFI, where, despite a higher amount of larvae provided compared with the present study, LW, ADG, ADFI and FCR were unaffected. By contrast, the daily provision of live BSF larvae (10% of the expected ADFI) to turkeys led to higher ADFI and body weight gain and a lower FCR than the control group [ 20 ].…”

“…The gross energy (GE) content of the larvae was determined using an adiabatic calorimetric bomb (C7000; IKA, Staufen, Germany). Finally, the amino acid analysis was performed as reported by Bongiorno et al [ 17 ]. The proximate composition of the BSF and YM larvae of both early and late instars is reported in Table 2 .…”

“…The ADFI was calculated on the as fed basis considering the average amount of larvae provided. Finally, the DM of the live BSF and YM larvae (25.26 and 38.30 g/100 g for BSF and YM early instar, 24.85 and 37.56 g/100 g for BSF and YM late instars, respectively) was used to adjust the FCR, according to the method reported by Bongiorno et al [ 17 ]. All the measurements were made using an electronic scale (Sartorius – Signum®, Bovenden, Germany; d = 0.1).…”

“…Recently, the effects of providing live insect larvae of the black soldier fly (BSF, Hermetia illucens ) and yellow mealworm (YM, Tenebrio molitor ) as environmental enrichment in poultry has been examined by a number of authors, who have evaluated their effects in terms of growth performance and animal behavior [ 17 – 19 ]. The results on growth performance vary greatly between the studies, probably due to the high variability in terms of the amounts of larvae provided and the methods adopted for larva provision (provided as a supplementation of the diet, included in the diet formula or scattered throughout the pen) and the avian species considered.…”

“…From a nutritional point of view, it is well known that insects are a nutrient-rich feedstuffs for livestock animals, being a good source of protein (with high biological value in terms of amino acid content), fat and energy. However, considering the application of whole insects as environmental enrichment, their water content (around 70%) must be considered, since it highly reduces the amount of provided nutrients (on a DM basis) [ 17 ]. On the other hand, from the results obtained in previous studies, it can be supposed that larvae motility might affect their attractiveness to the birds and encourage foraging behavior and the birds’ activity in general [ 19 – 21 ].…”