Determination of optimal standardized ileal digestible lysine to metabolizable energy ratios in diet for Cobb 500 broilers from 1 to 14 days of age
In this study, 400 day-old straight-run Cobb 500 broiler chicks sourced from a commercial hatchery were randomly allotted to treatment following a Randomized Complete Block Design (RCBD). The treatments used were fivve ratios of SID Lysine (Lys) to metabilizable energy (ME) in diet of 3.61, 3.89, 4.17, 4.45, or 4.73 g SID Lys/Mcal ME. There were 8 replicates per treatment with 10 birds in each cage. Result showed that increasing SID Lys to ME ratio improved (quadratic, P<0.01) day 14 body weigh (BW), body weigh gain (BWG), average daily gain (ADG), Feed conversion ratio (FCR) of broiler chicks from 1 to 14 day of age. No (P>0.05) significant differences were observed foraverage daily feed intake (ADFI) across the treatments. Broilers fed the diet containing 4.45 g SID Lys/Mcal ME had the greatest (P<0.01) BW, BWG, ADG, and FCR among all the treatments. Increasing SID Lys to ME ratio in diets did not affect (P>0.05) livability. Overall (day 1 to 33), a tendency for increased (quadratic, P=0.08) ADG and improved (quadratic, P=0.02) FCR in broilers were observed with increasing levels of SID Lys to ME ratios during the booster phase. At day 33 of age there were only numerical differences in BW across the treatments.
