The current study was conducted to explore the possible impact of soybean replacement with various levels of mealworm meal (MWM), Tenebrio molitor, on growth performance, carcass traits, meat quality, physiological status, and economic efficiency of broiler chickens. The study included 360 unsexed Cobb500™ commercial broiler chicks aged 1 day and weighing 46±1.5 g. Starting from the 22nd to the 42nd d of age, the chicks were randomly distributed according to the dietary inclusion levels of MWM into six treatment groups (6 replicate pens per group × 10 chicks per replicate, considering the equal ratio of males to females in each replicate). The first group of birds was fed a control finisher diet containing soybean-corn meal (0% MWM), while the remaining five groups of birds were provided with a finisher diet in which the soybean meal was partially replaced with 2%, 4%, 6%, 8%, and 10% MWM, respectively. Data were analyzed using the one-way analysis of variance (ANOVA) with a polynomial test to explore the linear and quadratic effects of increasing the MWM levels into the broiler diets. The results of this study showed a linear increase (p < 0.05) in the final body weight, body weight gain, carcass weight, dressing, and meat yellowness (b*) of broilers as the dietary MWM level increased. In addition, linear and quadratic increasing yields of liver, abdominal fats, and intestines were recorded with the increased levels of MWM. The carcass breast yield and the water retention capacity and the shear force of the broiler meat were linearly and quadratically (p < 0.05) increased, while the thawing and cooking loss of meat were decreased (p < 0.05) in response to the increase in the dietary MWM levels, up to 6%. Furthermore, some physiological aspects of the broilers, such as total protein, albumin, globulin, triiodothyronine hormone, triglycerides, and cholesterol profile concentrations in the serum were significantly (p < 0.05) improved by increasing the level of MWM into broiler diets up to 6%. In contrast, some traits of carcass composition and meat quality as well as physiological parameters deteriorated when adding higher levels of the MWM (8-10%) to the diets, compared to the control. Economically, there was a linear and quadratic (p < 0.05) decrease in the protein cost of the diet and a linear increase in birds’ total revenue and profit margin in response to increasing MWM levels in the broiler diet. However, MWM linearly (p < 0.05) decreased the cost-benefit-ratio (CBR) and the return-on-investment outcomes (RoI) due to the restrictive production and the high prices of MWM in the global market. In conclusion, the dietary inclusion of MWM as a replacement of the soybean meal has a beneficial effect on the growth performance, carcass and meat characteristics, and physiological aspects of broiler chickens provided that it is used within the recommended levels, i.e., not exceeding 6% in the broiler diets. However, the economic feasibility of MWM inclusion into broiler diets remains at low CBR and RoI rates at the current time because of the restrictive marketing and the excessive cost of MWM production.
Keywords | Mealworm meal, Broiler chickens, Growth, Carcass traits, Meat quality, Physiological aspects, Economic efficiency