THE DIGESTIBILITY BY PIGS OF DRY MATTER, ENERGY, PROTEIN AND AMINO ACIDS IN WHEAT CULTIVARS. I. GLENLEA, NEEPAWA, INIA-66, PITIC-62 AND TWIN, COMPARED WITH BONANZA BARLEY

Abstract

Wheat cultivars (Triticum vulgare L., ’Glenlea,’ ’Neepawa,’ ’Inia-66,’ ’Pitic-62’ and ’Twin’) and barley (Hordeum vulgare L., ’Bonanza’) were compared in digestion trials with six 40-kg barrows in a 6 × 6 latin square experiment. The diets contained 95.7% ground grain, 0.5% chromic oxide feces marker, mineral and vitamin supplements. Inia-66, Neepawa and Pitic-62 wheats had higher dry matter, energy and protein digestibility coefficients than Glenlea or Twin. Barley yielded the lowest values mainly because of having a higher fiber (hull) content and a lower protein content than the wheat samples. The digestible energy values (MJ/kg) also showed Glenlea and Twin wheats to be inferior (P < 0.05) to the other three cultivars. Differences in digestible crude protein (DCP) and in amino acid availability showed Neepawa and Pitic-62 to be superior to Twin. Lysine was the least available of the essential amino acids; 66–74% vs. 79% for the average of all amino acids in wheat. The variations in DCP and lysine availability in wheat may be more important nutritionally than the variations in DE.Key words: Digestibility, wheat, protein, energy, amino acids, pigs