Effect of Taurine in Rat Milk on the Growth of Offspring.

Abstract

ABSTRACT. The physiological significance of taurine in milk in the growth of rat pups was investigated. Our results confirmed that taurine was at an exceptionally high concentration in rat milk during the lactational period, especially for the first few days after birth. Pups taking no milk from natural dams but from foster mothers at an advanced lactational period showed a slower growth rate. Intraperitoneal administration of taurine to the foster mothers in the first five days restored this growth retardation. On the other hand, intraperitoneal administration of β-alanine, a transport antagonist of taurine, to the natural dams through the lactational period induced a slower growth rate of pups. This β-alanine treatment to dams increased β-alanine concentration, but did not decrease taurine concentrations in milk, and serum taurine concentration in the pups receiving this milk was elevated. Direct administration of β-alanine to pups also increased the serum taurine concentrations dose-dependently. β-Alanine administration to pups significantly decreased [ 3 H]taurine incorporation into all the organs examined, and in contrast, [ 3 H]taurine concentrations in serum and urine were elevated. Thus, β-alanine inhibited taurine incorporation into cells and accelerated taurine excretion into either urine or milk. Serum IGF-I levels in pups receiving β-alanine either directly or via their mothers was significantly lower than those in control pups. Cumulatively, taurine ingestion from milk at an early lactational period seems critical for normal growth of rat neonates due to its role in maintaining normal serum IGF-I levels.KEY WORDS: β-alanine, growth rate, milk, rat pup, taurine.J. Vet. Med. Sci. 62 (7): [693][694][695][696][697][698] 2000 Taurine (2-aminoethane sulphonic acid) is one of the end products of sulfur metabolism, first isolated from ox bile [29], and was considered for a long time to be an inert waste product of the sulfur-containing amino acid catabolism. However, as information concerning the biological roles of taurine has accumulated, taurine has been illustrated to play many important physiological roles in animals, especially during their development. The possible functions of taurine currently proposed are as follows: conjugation of bile acids in the liver [31], improvement of fat absorption [1], maintenance of osmolarity [17], modulation of calcium levels [30], stabilization of membranes [12], antiarrhythmic activity in the heart [24], regulation of ion fluxes [7], and stimulation of sperm motility [20]. In the central nervous system, although the role of taurine is not well established, it has been proposed as a neurotransmitter or a neuromodulator [2]. In addition, taurine seems to be involved in the development of the brain, since taurine concentrations in the brain fall with development and the levels of taurine in adults is about one-third of those of neonates. This pattern has been found in many species including rats [5].Taurine is an essential amino acid for the cat because the cat has ...

β-Alanine Enhances Brain and Muscle Carnosine Levels in Broiler Chicks

“…Further study should be done to clarify this hypothesis. As pointed out in the introduction, tissue taurine depletion could induce physiological dysfunctions such as growth retardation (Sturman, 1993;Hu et al, 2000). In the present study, no significant negative effects were observed in growth parameters such as feed consumption, body weight gain, feed efficiency, MPS weight and whole brain weight (Table 1).…”

“…β-Ala levels of brain, MPS and plasma were dose-dependently increased while their taurine levels were decreased in a dose-dependent manner. Taurine depletion was commonly observed following β-Ala treatment because β-Ala competes with taurine for uptake (Hu et al, 2000;Tomonaga et al, 2005bTomonaga et al, , 2006. The supplemental β-Ala in the present study successfully competed with taurine.…”

“…Among the free amino acids, in addition to the constituent amino acids, we focused on taurine. Administration of β-Ala induces tissue taurine depletion because β-Ala competes with taurine for uptake mechanisms (Hu et al, 2000;Tomonaga et al, 2005bTomonaga et al, , 2006. Furthermore, tissue taurine depletion evokes physiological dysfunctions such as growth retardation (Sturman, 1993;Hu et al, 2000).…”

Expression of Cysteine Sulfinate Decarboxylase mRNA in Rat Mammary Gland.

“…The hepatic taurine pool appears to increase just before parturition and rapidly decrease after the first few days of lactation when high levels of taurine are secreted into the milk [15]. However, the data in our previous study indicated that taurine concentrations in milk always highly exceeded those in dams' peripheral circulation, and administration of β-alanine, a transport antagonist of taurine, to lactating dams did not decrease taurine concentrations in the milk [5]. These observations make us hypothesize that taurine can be synthesized by the mammary gland, and that taurine synthesized in the mammary gland may be another important source of taurine in the milk.…”

“…We have also recently shown that high concentrations of taurine, especially at the beginning of lactation, is mandatory for normal body growth of rat pups presumably by maintaining insulin-like growth factor-I (IGF-I) levels in the blood [5]. Taurine in milk is thought to be derived from the liver, because the milk taurine level was positively correlated with hepatic taurine concentration during a lactational period [15].…”