Nutritional and cost effects of adapted quality protein maize on broiler feeding

Abstract

ZPQPM13 is a maize hybrid with improved protein quality, adapted to temperate climate growth conditions, developed by crossing a QPM version of ZPL5 commercial line (developed by marker assisted selection) and GS-6 (a QPM line with 50% tropical and 50% temperate germplasm). This hybrid has grain yield as commercial hybrids, over 90% of hard endosperm, contents of tryptophan and protein over 0.075% and 10%, respectively, and stability of tryptophan content over different locations and years. ZPQPM13 was tested for use in broiler feeds, with the aim to reduce utilization of costly synthetic lysine or soybean components. The feeding experiment on Ross 308 broilers was divided into two groups – control (fed with standard maize) and treatment (fed with QPM). In treatment group diets, ZPQPM13 was increased and soybean component decreased for 3%. Chemical analyses revealed higher contents of limiting essential amino acids in mercantile ZPQPM13 compared to standard maize – 0.44 vs. 0.25 % lysine, 0.077 vs. 0.070 % tryptophan and 0.39 vs. 0.27 % threonine. Duration of each feeding trial was 42 days, comprising three phases - starter (1-14 days), grower (15-35 days) and finisher (36-42 days). Feed intake (FI), body mass gain (BMG), average daily gain (ADG) and feed conversion ratio (FCR) were calculated at the end of each phase. In treatment group, FI was reduced, while BMG and ADG were higher in starter phase but lower in grower and finisher phases. FCR was lower in all three phases in treatment group – 1.13 vs. 1.30, 1.25 vs. 1.33 and 1.28 vs. 1.45. Although a small drawback is that final weight was 3.4 % higher in control broilers, comparison of feed and meat prices show that financial benefits of using QPM are still significant compared to using standard maize in feeds, as soybean is four times more expensive than maize.