Preliminary Indications that Exogenous Phytase Influences Amino Acid and Glucose Catabolism in the Gut Mucosa

Wheat-soybean meal diets containing 0, 500, 1000 and 2000 FTU/kg phytase included over the top were offered to 192 male Ross 308 chicks (8 replicate cages) from 7 to 28 days post-hatch to determine the influence of exogenous phytase on concentrations of glutamic acid + glutamine and glucose in portal plasma and the effects of 500 FTU phytase on portal plasma amino acid concentrations. 500 FTU/kg phytase significantly (P < 0.05) increased plasma concentrations of isoleucine, leucine, lysine, phenylalanine, tryptophan, valine and serine. Additionally, phytase inclusions linearly reduced concentrations of glutamic acid plus glutamine (r = -0.363; P < 0.05) and logarithmically increased plasma glucose levels (R² = 0.127; P < 0.05). Glutamic acid plus glutamine to glucose concentration ratios in portal plasma were related to both FCR (R² = 0.374; P < 0.005) and phytase inclusions (R² = 0.252; P < 0.05). Thus, phytase may be manipulating the metabolic fate of glucose and amino acids within the gut mucosa; thereby contributing to improvements in feed efficiency. These findings indicate that further investigations are justified.