title: Energy evaluation of eight barley cultivars for poultry: effect of dietary enzyme addition.
abstract: Three experiments were conducted to study eight barley cultivars and the effect of enzyme addition on their energy value for poultry. In Experiment 1, the AMEn of a reference barley (Beka cultivar) was calculated by increasing barley concentrations (30, 40, 50, and 60%) that replaced a high protein basal diet. In Experiment 2, eight barley cultivars (four spring and four winter cultivars) replaced the reference barley in the diet with 50% barley inclusion. Two of the winter cultivars were two-rowed and two were six-rowed cultivars. A commercial enzyme was added to these diets to study the effect of enzyme addition. Diets were consumed ad libitum by 27 and 145 21-d-old Arbor Acres broiler chicks, in Experiments 1 and 2, respectively. In Experiment 3, 66 adult roosters were used to determine the TMEn of the eight cultivars used in Experiment 2. Dietary AMEn decreased linearly (P < 0.05) with increasing barley (Beka cultivar) inclusion. Beka barley AMEn was calculated by extrapolation of the linear regression equation be equal to 2,980 kcal/kg DM. Barley energy value was influenced by cultivar (P < 0.001); the spring cultivars showed greater energy value than the winter cultivars (2,963 vs 2,852 kcal AMEn/kg DM; 3,192 vs 2,929 kcal TMEn/kg DM). Two-rowed cultivars showed higher TMEn than six-rowed winter cultivars, although no differences were found for AMEn. The correlation between AMEn and TMEn values of barley was relatively low (r = 0.69); therefore, barley TMEn cannot be extrapolated to AMEn for young chicks. Enzyme addition produced an average increase of 220 kcal/kg DM in barley AMEn (P < 0.001); there was a significant (P < 0.10) interaction between barley cultivar and enzyme supplementation. The increment of barley AMEn caused by enzyme addition was partly explained (47%) by an increase in barley viscosity. This relationship implies that enzyme supplementation significantly improves the feeding value of high as compared to low viscosity barley samples, which involved a decrease in AMEn variation among cultivars for enzyme-supplemented barley. No relationship was found between AMEn of unsupplemented barley cultivars and their chemical composition. Instead, a relationship was detected for enzyme-supplemented barley; therefore two equations were proposed for predicting the AMEn of enzyme-supplemented barley to be used directly in diet formulation.
authors.affiliation: Departamento de Producción Animal, E.T.S.I. Agrónomos, Universidad Politécnica, Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Villamide
authors.forename: J M
authors.initials: JM
authors.lastname: Fuente
authors.forename: P
authors.initials: P
authors.lastname: Perez de Ayala
authors.forename: A
authors.initials: A
authors.lastname: Flores
mesh_terms: D000818:Animals; D002645:Chickens / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D004798:Enzymes / Q000008:administration & dosage / Q000494:pharmacology*; D005527:Food, Fortified; D001467:Hordeum / Q000378:metabolism / Q000592:standards*; D008297:Male
chemical_list: D004798:Enzymes