Gut microbiota modulate host behavior by altering their brain function through vagal nerve stimulation, the immune system, or the release of hormones. We recently reported that the gut microbiota modifies free amino acid concentrations in the brain. Although many studies of functional lactobacillus have been reported, the role of lactobacillus in learning ability has not been clarified. Cognitive dysfunction syndrome with aging causes abnormal behavior and memory disorders in many animals, including humans,dogs or cats. We investigated the effect of long-term administration of yoghurt （fermented by Lactobacillus delbrueckii subsp. bulgaricus 2038 and Streptococcus thermophilus 1131） on the spatial memory and amino acid and monoamine concentrations in the cerebral cortex of mice. Long-term administration of yoghurt improved the test scores for spatial reference memory on the eight-arm radial maze and increased 5-hydroxytryptamine,and the cerebral cortex concentrations of free L-alanine, D- and L-serine, L-valine, and L-isoleucine. These results suggest that the long-term intake of yoghurt by mice might improve the spatial reference memory through modification of the metabolism of several amino acids and 5-hydroxytryptamine in the cerebral cortex.

Many domestic cats eating commercial complete balanced dry cat foods as main food suffer from vomiting. Many owners bothered their cat's vomiting, but they didn't take measures. Hairballs vomiting can be relieved by hairballs care cat food including cellulose fiber, sugarcane fiber and psyllium ［1,10,11,26］, but there have not been techniques for relieving foods vomiting. The kibbles of conventional pet food shed water due to the solid surface and the abundant oil coating. This feature possibly delays the absorption of gastric juice into the kibbles in stomach. It can be presumed that taking time for dry food to be soften in stomach cause foods vomiting. Main purpose of this study was to develop the techniques for relieving foods vomiting of cats. Kibbles combining high water absorbing and releasing property were developed by using Lignocellulose, new type purified cellulose and new manufacturing method. Cats eating dry food as main food and vomiting dry foods once or more every week were fed only test samples for 3 weeks. These test samples could relieve the foods vomiting （P＜0.01） and their owners realized the effect. The pepsin digestibilities of high water absorbing and releasing kibbles were significantly higher than control （P＜0.01）. It is suggested that the quick digestion in stomach by high water absorbing and releasing property of kibbles leads to relief of foods vomiting in cats.