1- Department of Animal Science, College of Agriculture, University of Tehran, Karaj, Islamic Republic of
Iran.
Abstract: (6168 Views)
An experiment was conducted to reevaluate the digestible lysine requirement of Arian male broilers by comparing the performance of chicks fed different levels of cottonseed meal (CSM) on a total amino acid (AA) versus a digestible AA basis. Four hundred and thirty two (432) Arian male broiler chicks were allotted to 18 treatments with four repli-cates of six chicks each in a completely randomized block design in a factorial arrange-ment with two factors (two levels of digestible lysine nine different diets). The first of the eighteen treatments was the corn and soybean meal control diet based on previously de-termined digestible lysine requirement for maximum body weight gain. Diets 2 to 5 con-tained 5, 10, 15 or 20% CSM, respectively and were formulated to contain levels of total AA equivalent to those in the first treatment. Diets 6 to 9 contained the same levels of CSM as diets 2 to 5 but the diets were formulated to be equal in digestible AA content to the first treatment. Treatments 10 to 18 were the same as treatments 1 to 9, but on the ba-sis of determined digestible lysine requirement for maximum feed efficiency. Formulating diets containing CSM on a digestible AA basis resulted in an improvement in chick per-formance compared to those formulated on a total AA basis (P<0.01). The lessening of chick performance with diets formulated on a total AA basis compared to a digestible AA basis, indicated that the previously determined digestible lysine requirement for the Arian broiler strain may be correct.
Received: 2010/01/28 | Accepted: 2010/01/28 | Published: 2010/01/28