Neuroexcitatory plasma amino acids are elevated in migraine.

To investigate the role of glutamic (Glu) and aspartic acid (Asp) in migraine, we measured the plasma amino acids in migraine patients with and without aura, between and during attacks, and compared the profiles with the plasma amino acid profiles of tension headache patients and healthy controls. Between attacks, migraineurs (notably with aura) had substantially higher plasma Glu and Asp levels than did controls and tension headache patients. In addition, patients with migraine without aura showed low plasma histidine levels. During migraine attacks, Glu (and to a lesser extent Asp) levels were even further increased. The results suggest a defective cellular reuptake mechanism for Glu and Asp in migraineurs, and we hypothesize a similar defect at the neuronal/glial cell level, predisposing the brain of migraineurs to develop spreading depression.

Improvement of phosphorus availability by microbial phytase in broilers and pigs.

Techniques have been developed to produce microbial phytase for addition to diets for simple-stomached animals, with the aim to improve phosphorus availability from phytate-P in plant sources. The activity of the crude microbial phytase showed pH optima at pH 5.5 and 2.5. The enzyme was able to degrade phytate in vitro in soya-bean meal, maize and a liquid compound feed for pigs. When microbial phytase was added to low-P diets for broilers the availability of P increased to over 60% and the amount of P in the droppings decreased by 50%. The growth rate and feed conversion ratio on the low-P diets containing microbial phytase were comparable to or even better than those obtained on control diets. Addition of microbial phytase to diets for growing pigs increased the apparent absorbability of P by 24%. The amount of P in the faeces was 35% lower.