Effects of dietary Tenebrio molitor meal inclusion in free‐range chickens

Abstract

Insects are currently being considered as a novel protein source for animal feeds, because they contain a large amount of protein. The larvae of Tenebrio molitor (TM) have been shown to be an acceptable protein source for broiler chickens in terms of growth performance, but till now, no data on histological or intestinal morphometric features have been reported. This study has had the aim of evaluating the effects of dietary TM inclusion on the performance, welfare, intestinal morphology and histological features of free-range chickens. A total of 140 medium-growing hybrid female chickens were free-range reared and randomly allotted to two dietary treatments: (i) a control group and (ii) a TM group, in which TM meal was included at 75 g/kg. Each group consisted of five pens as replicates, with 14 chicks per pen. Growth performance, haematological and serum parameters and welfare indicators were evaluated, and the animals were slaughtered at the age of 97 days. Two birds per pen (10 birds/treatment) were submitted to histological (liver, spleen, thymus, bursa of Fabricius, kidney, heart, glandular stomach and gut) and morphometric (duodenum, jejunum and ileum) investigations. The inclusion of TM did not affect the growth performance, haematological or serum parameters. The morphometric and histological features were not significantly affected either, thus suggesting no influence on nutrient metabolization, performance or animal health. Glandular stomach alterations (chronic flogosis with epithelial squamous metaplasia) were considered paraphysiological in relation to free-range farming. The observed chronic intestinal flogosis, with concomitant activation of the lymphoid tissue, was probably due to previous parasitic infections, which are very frequently detected in free-range chickens. In conclusion, the findings of this study show that yellow mealworm inclusion does not affect the welfare, productive performances or morphological features of free-range chickens, thus confirming that TM can be used safely in poultry diets.

Black soldier fly as dietary protein source for broiler quails: apparent digestibility, excreta microbial load, feed choice, performance, carcass and meat traits

“…Results on chicken broilers were consistent with our findings: when free-range chicken fed either a control diet or a diet in which gluten meal was replaced with T. molitor meal, the same average daily feed intake was observed (Biasato et al, 2016). Similar results were found when a T. molitor meal replaced soya bean meal with hulls in the diet for broiler chickens (Bovera et al, 2015).…”

Effect of Tenebrio molitor larvae meal on growth performance, in vivo nutrients digestibility, somatic and marketable indexes of gilthead sea bream (Sparus aurata)

“…It is already raised on an industrial scale, but there are few data in literature on its use in animal feeding. Tenebrio molitor larvae meal (TM) has been used in broiler De Marco et al, 2015;Biasato et al, 2016) and laying hens (Giannone, 2003;Wang et al, 2005). In fish, TM was used in African catfish (Ng et al, 2001), rainbow trout , and European sea bass , black bullhead (Roncarati et al, 2015) with encouraging results.…”

ASPA 22nd Congress Book of Abstracts

“…Moreover, no limitations are reported for the use of insect oil in animal feeds. Among insect species, black soldier fly (Hermetia illucens), yellow mealworm (Tenebrio molitor), and common housefly (Musca domestica) are the most evaluated and results on their inclusion on animal feed are promising (Barroso et al 2014;Makkar et al 2014;Belforti et al 2015;Veldkamp and Bosch 2015;Biasato et al 2016;Gasco et al 2016;Schiavone et al 2017;Piccolo et al 2017;Renna et al submitted). EU regulation authorises among other insect species, both H. illucens and T. molitor.…”

“…defatting procedures), the feed formulation (level of IM inclusion and conventional protein substitution), and, of course, the animal age and species. Generally speaking, dietary inclusion up to 35% to 40% seems feasible in freshwater species, without worsening the performance parameters, while in marine species, 25% inclusion results to be the maximum acceptable amount especially in fingerlings (Gasco et al 2016;Piccolo et al 2017). As far as poultry is concerned, inclusion levels of up to 15% lead to promising results.…”

“…Little research has been done so far to evaluate IM in pig production but the inclusion of up to 10% results feasible (Bressan et al 2017). The dietary inclusion of IM and insect oil influences the meat and flesh quality, mainly the fatty acid composition (Belforti et al 2015;Gasco et al 2016;Schiavone et al 2017;Renna et al submitted). IM and insect oil are rich in saturated and monounsaturated fatty acids and completely lack in n-3 long chain polyunsaturated fatty acids (Makkar et al 2014;Henry et al 2015).…”