Digestible Lysine Requirement of Arian Male and Female Broiler Chicks During Six to Twenty-one Days of Age

An experiment was conducted to determine the dietary digestible lysine requirement of male and female broiler chickens (Arian) during the period from ۶ to ۲۱ days post-hatching. An amino acid-fortified basal diet containing corn and soybean meal as intact protein sources provided ۲۰ % CP, and ۳۲۰۰ kcal AMEn / kg. In this experiment ۱۵۰ male and ۱۵۰ female chicks were allocated on the basis of BW to ۱۲ treatments in a factorial arrangement (two sexes at six digestible lysine levels) with five replications of five chicks each in a completely randomized design (CRD). The digestible lysine levels fed were ۰.۸۵, ۰.۹۵, ۱.۰۵, ۱.۱۵, ۱.۲۵ and ۱.۳۵%. The growth rate and feed efficiency of birds fed the basal diet fortified with a surfeit level of l-Lysine-HCl were equal to those of birds fed a corn-soybean meal positive control diet. Average body-weight gain (ABWG) and gain: feed (GF) responded quadratically (P<۰.۰۵) to incremental dietary lysine addition. Subjecting the growth data to broken-line analysis indicated that the digestible lysine requirement for maximum body weight gain was ۱.۰۷۵% for males and ۱.۰۴۹% for females. The lysine requirement for maximum feed efficiency was ۱.۱۷۹% for males and ۱.۱۴۹% for females. Male chicks required a higher level of dietary lysine than females for both maximal ABWG and GF. Regardless of sex, ۸.۸% more digestible lysine (percentage of diet) was required for maximal GF than that needed for maximal ABWG.

Keywords:

Digestible amino acid , Broiler chickens , Lysine requirement