Supplementation of L-Ornithine Could Increase Sleep-like Behavior in the Mouse Pups.

Along the maternal-fetal-neonatal axis, one of the problems relating to the maternal-neonatal axis is infant sleep problems including nighttime crying. One possible solution could be to provide the newborn with sleep-promoting ingredients through breast milk or formula. So far, it has been reported that L-ornithine has a sleep-related effect.

Orally administrated D-arginine exhibits higher enrichment in the brain and milk than L-arginine in ICR mice.

D-Amino acids exert various physiological functions and are widely present in animals. However, they are absorbed to a lesser extent than L-amino acids. Little is known about D-arginine (D-Arg); however, its isomer L-Arg serves as a substrate for several metabolites and exhibits various functions including promotion of growth hormone secretion.

Oral administration of l-ornithine increases the content of both collagen constituting amino acids and polyamines in mouse skin.

l-Ornithine is found in animals as a free amino acid and is a vital component of the urea cycle in the liver; it is reported to have various functions such as promoting wound healing, promoting growth hormone secretion, hypnotic effects, and so on. The present study aimed to investigate the effects of a single oral administration of l-ornithine on 1) the metabolism of amino acids in the liver and skin of mice and 2) the metabolism of polyamines in the skin of mice. To this end, ICR mice were separated into five groups; four groups were administered l-ornithine dissolved in fresh water (3.

Restraint stress in lactating mice alters the levels of sulfur-containing amino acids in milk.

It is well known that maternal stress during the gestation and lactation periods induces abnormal behavior in the offspring and causes a lowering of the offspring's body weight. Various causes of maternal stress during the lactation period, relating to, for example, maternal nutritional status and reduced maternal care, have been considered. However, little is known about the effects on milk of maternal stress during the lactation period.

Dietary L-serine modifies free amino acid composition of maternal milk and lowers the body weight of the offspring in mice.

The growth of offspring is affected not only by the protein in maternal milk but also by the free amino acids (FAAs) contained in it. L-Serine (L-Ser) is known as an important FAA for the development of the central nervous system and behavioral activity. However, it is not clear whether L-Ser is transported into the pool of FAAs contained in milk and thereby affects the growth of offspring.

Taurine and β-alanine intraperitoneal injection in lactating mice modifies the growth and behavior of offspring.

Taurine, one of the sulfur-containing amino acids, has several functions in vivo. It has been reported that taurine acts on γ-aminobutyric acid receptors as an agonist and to promote inhibitory neurotransmission. Milk, especially colostrum, contains taurine and it is known that milk taurine is essential for the normal development of offspring.