Mealworm inclusion in Label chicken diet does not affect both performance and welfare parameters

The use of insects as an alternative source of protein in animal feed is becoming more globally appealing, also in poultry. Soybean or fish meal in broiler chicken or laying hen have been successfully replaced at low inclusion levels by black soldier flies (Hermetia illucens), housefly (Musca domestica), mealworms (Tenebrio molitor, TM) and silkworm (Bombix mori) pupae. In this experiment, female Label chickens were reared in free range condition (5 replicates per treatment and 12 birds per replicate). Birds were housed at the age of 42 days (average weight 715 g). Two experimental diets were designed: 72.0% corn, 17.0% soybean meal, 7.5% gluten meal (C-group) or mealworm meal (TM-group) and 3.5% mineral-vitamin premix. Diets were formulated using AMEn values calculated for broiler chickens by our research group (Schiavone et al., 2015). C-group and TM group diets were isoenergetic (AMEn: 12.18 and 12.22 MJ/kg, respectively) and isonitrogenous (crude protein: 16.9% and 16.8%, respectively). The experiment lasted 60 days. Birds were weighted at the beginning and at the end of the experiment. At slaughtering, blood samples were taken and the main commercial cuts were evaluated (carcass for grilling, breast and thigh) as well as liver, spleen and Bursa of Fabricius weights. In addition foot pad dermatitis score was evaluated according to the EU Commission recommendations. Data were analysed by Student's t-Test for independent samples. C-group and TM-group displayed similar final body weight (2131 vs. 2162 g), feed conversion ratio (4.37 vs. 4.36 g), carcass for grilling (1459 vs. 1545 g), breast (347 vs. 371 g), thigh (497 vs. 503 g), abdominal fat (41 vs. 45 g), liver (37 vs. 39 g), spleen (4.0 vs. 3.8 g) and Bursa of Fabricius (4.3 vs. 4.2 g). By comparing blood analysis of C-group vs. TMgroup data of red (2.4 vs. 2.6 millions) and white blood cells (9.4 vs. 9.9 thousands), H/L ratio (0.55 vs. 0.51), total protein (3.98 vs. 4.05 d/dl), AST (190 vs. 198), ALT (14.5 vs. 14.0 UI/l), uric acid (5.0 vs. 3.9 mg/dl), triglycerides (43.4 vs. 47.8 mg/dl) and glucose (262 vs. 244 mg/dl) no significant differences were found. Birds did not displayed any foot pad dermatitis lesion. In conclusion TM meal can be safely used as feed ingredient for Label chicken at the inclusion level of 7.5% without affecting growth and slaughter performance as well as blood and welfare parameters.