High-protein maize in diets for broilers

Abstract

The nutritional performance of three high-protein maize hybrids was compared with conventional maize in a 42-day feeding trial in broilers. The following experimental diets were compared: i) control diet (CTR) containing conventional maize; ii) diet containing hybrid IPM1; iii) diet containing hybrid IPM2; iv) diet containing hybrid IPM3. The diets were offered to male broilers (Hubbard Ultra-Yield; 120 birds per treatment) in 3 phases: starter, grower and finisher. All the diets were iso-nitrogenous and iso-energetic. The IPM2 and IPM3 diets (containing maize grains with the highest protein and essential and non-essential amino acid contents) resulted in a higher final weight in broilers (2622 and 2632 g, respectively, versus IPM1 and CTR diets; P<0.05), a higher average daily gain (60.8 and 61.4 g/d, respectively, versus IPM1 and CTR diets; P<0.05) and better feed to gain ratios (1.70 and 1.69, respectively, versus the CTR diet; P<0.05) throughout the experimental period. The nutritional characteristics of the different maize varieties were also evaluated using a 9-day digestibility trial in male rats (6 rats per treatment). Higher percentages of nitrogen retention were obtained from the IPM2 (54.02%) and IPM3 (53.51%) diets compared with the CTR (44.20%) and IPM1 (41.87%) diets (P<0.05). These results suggest a greater amino acid availability in the diets based on high-protein maize varieties. Therefore, high-protein maize can profitably be included in broiler diets with the advantage of reducing the use of imported protein sources (such as soybean meal) because of its higher protein content and consequently, providing savings on feed costs.