Levels of endogenous β-glucanase activity in barley affect the efficacy of exogenous enzymes used to supplement barley-based diets for poultry

• Published in: Poultry science 2011-06, Vol.90 (6), p.1245-1256
• Main Authors: Ribeiro, T, Lordelo, M.M.S, Ponte, P.I.P, Maçãs, B, Prates, J.A.M, Aguiar Fontes, M, Falcão, L, Freire, J.P.B, Ferreira, L.M.A, Fontes, C.M.G.A
• Format: Article
• Language: English
• Subjects: Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; barley; beta-glucans; broiler chickens; Cellulase - pharmacology; diet; Diet - veterinary; Dietary Supplements; endo-1,4-beta-glucanase; feeds; Glucans - metabolism; Glycoside Hydrolases - metabolism; Hordeum - enzymology; Nutritive Value; Recombinant Proteins
• ISSN: 0032-5791; 1525-3171
• DOI: 10.3382/ps.2010-01218

To improve the nutritive value of barley-based diet for broilers, 2 experiments using 2 different barley lots were performed to evaluate the capacity of a mesophilic cellulase when fused to a β-glucan specific family 11 carbohydrate-binding module. The data revealed that the recombinant β-glucanase derivatives were not appropriate for feed supplementation because of a lack of stability at acidic pH levels. However, under the same experimental conditions, a commercial enzyme mixture improved the nutritive value of 1 of the cereal lots used. Analysis of the nutritive value of the 2 barleys revealed intrinsic differences in the levels of endogenous β-glucanase activity. These differences were extensively evident when the studies were expanded to a range of 64 barley lots. Thus, to clarify the effect of endogenous cellulases on the efficacy of exogenous β-glucanases used to supplement barley-based diets for poultry, 2 barley lots presenting low and high levels of endogenous plant cell wall-degrading enzymes were selected. These lots were used to prepare 2 barley-based diets, which were supplemented with or without a commercial enzyme product and fed to broiler chicks. The data revealed that the exogenous enzymes were effective when the basal diet presented low levels of endogenous β-glucanases but were unable to improve the nutritive value of the barley lot displaying higher β-glucanase activity. Thus, these studies suggest that levels of endogenous β-glucanases may affect the efficacy of exogenous enzymes used to improve the nutritive value of barley-based diets for broilers. The development of a quick β-glucanase assay that could be applied for cereal-based feeds may help identify those barley-based diets that are more responsive to the action of feed enzymes.