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Pretreating fibrous feedstuffs with exogenous enzymes may improve their utilization in broiler chickens. Pretreatment of wheat middlings ( WM ) and sunflower meal ( SM ) with fiber degrading enzymes ( FDE ) was investigated for 1) in vitro solubilization of crude protein ( CP ) and fiber-degrading (experiment 1), and 2) apparent retention ( AR ) of CP, neutral detergent fiber ( NDF ), nitrogen corrected apparent metabolizable energy ( AMEn ), as well as the concentration of ceca digesta metabolites in broiler chickens (experiment 2). In experiment 1, WM was pretreated with FDE and SM with FDE ± protease and incubated in a shaker for 24 or 48 h at 40°C and 200 rpm. Samples were centrifuged, and the supernatant used for assay of sugars and organic acids and pellet processed for determination of apparent disappearance ( AD ) of dry matter ( DM ), fiber, and CP solubilization. In experiment 2, WM and SM were pretreated with FDE for 24 h, oven-dried, and incorporated in iso-caloric and iso-nitrogenous experimental diets. Diets were: 1) a corn-soybean meal positive control ( PC ); 2) PC plus untreated WM and SM (negative control, NC ), and diets 3, 4, 5, and 6 test diets, in which the untreated WM and SM in NC were replaced with pretreated WM and SM at 25% (N25), 50% (N50), 75% (N75), and 100% (N100), respectively. Diets were prepared in mash form in two phases (starter, days 0 to 21 and finisher, days 22 to 42) and had TiO 2 (0.3%) as an indigestible marker. A total of 288 Ross708 d-old male broiler chicks were placed in cages based on body weights (6 birds/cage) and allocated diets ( n  = 8). Birds had free access to feed and water. Samples of excreta for AR and AMEn, and of ceca digesta for the concentration of short-chain fatty acids ( SCFA ) were collected at the end of each phase. Pretreatment with FDE increased ( P  < 0.001) solubilization of CP, AD of NDF, and release of sugars and organic acids in the supernatant. The mixture of FDE and protease further increased ( P  < 0.001) CP solubilization in SM. Feeding pretreated WM and SM had a linear response ( P  ≤ 0.038) on AMEn, and gross energy ( GE ) (day 21) and a quadratic response ( P  < 0.05) on AR of components and AMEn (day 42) and concentration of total SCFA on day 42. On day 42, N25 and N50 had higher AR of DM, CP, NDF, and GE than N75 and N100. In conclusion, pretreatment of WM and SM with enzymes increased CP and fiber degradation. Incorporating moderate amounts (N25 and N50) of pretreated WM and SM in a corn-soybean meal diet fed to broiler chickens improved nutrient and energy utilization., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. R.P. is an employee of Canadian Bio-Systems Inc., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The ever-increasing animal feed costs are driving many vulnerable communities involved in animal husbandry out of business. The high cost is mainly driven by the protein source, which represents the most expensive component in animal feed. In conventional feed, protein is obtained mainly from soybean and fish meal (SFM). The present study explored potential of partially replacing this SFM with black soldier fly prepupae meal (BSFPM) in Cobb 500 broiler chicken diets. A SFM-based diet was compared to three experimental diets formulated by partially substituting SFM with BSFPM at 13.8, 27.4, and 42.0% of the crude protein (CP) in the starter feed and 11.0, 37.2, and 55.5% of the CP in the finisher feed of diets D1, D2, and D3, respectively. Dietary effects on average daily feed intake, average daily body weight gain, feed conversion ratio, carcass characteristics, breast meat sensory attributes, and the economic implication of their use in broiler production were evaluated. Replacement of SFM with BSFPM did not affect daily feed intake, daily body weight gain, feed conversion ratio, aroma or taste of cooked breast meat. A 16.0% higher Cost Benefit Ratio and 25.0% better Return on Investment was recorded when the birds were reared on the highest concentration of black soldier fly (D3) compared to the conventional diet which was 19.0% more expensive. The implication of these findings for the promotion of insect mass production enterprises for animal feed protein, and their potential for income generation and job creation particularly in developing countries is discussed., (© The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)