| Co-Investigator(Kenkyū-buntansha) |
ODA Shin-ichi TOHOKU UNIVERSITY, FACULTY OF AGRICULTURE, RESEARCH ASSOCIATE, 農学部, 助手 (60211827)
SHOJI Yoshio TOHOKU UNIVERSITY, FACULTY OF AGRICULTURE, RESEARCH ASSOCIATE, 農学部, 助手 (60005642)
KATOH Kazuo TOHOKU UNIVERSITY, FACULTY OF AGRICULTURE, ASSOCIATE PROFESSOR, 農学部, 助教授 (60091831)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1991: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1990: ¥3,900,000 (Direct Cost: ¥3,900,000)
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| Research Abstract |
It is established that growth hormone (GH), insulin and glucagon are major hormones to control energy distribution, contributing to increase milk yield in the ruminants. We previously reported that the secretion of these hormones was modified by several amino acids in sheep (Kuhara et al., 1991). The aim of the present study was to investigate the effects of administration of amino acids on hormone and metabolite concentrations in lactating goats.
In Experiment 1, the ration was increased to fit the energy requirement for maintenance of lactation. In Experiment 2, the ration was increased to overcome the energy requirement. In both Experiments, either of amino acids (Asp, Leu, Ala and Gly) was infused into the jugular vein of lactating and non-lactating animals at 3 mmol/kg B.W./30 min. In Experiment 3, the administration was continued for 6 days at the energy level of Experiment 1.
In Experiment 1, secretory increment of GH in response to the amino acid administration was enhanced, while that of insulin was suppressed during the lactating period. A rise in amino N concentration was suppressed, but that in FFA concentration was enhanced, in response to the administration during the lactating period. A significantly positive interaction was observed between milk yield and plasma IGF-I concentration. In Experiment 2, however, GH response was suppressed, and the basal concentration of insulin and glucagon was increased during the lactating period. In Experiment 3, the concentration of GH, insulin and glucagon was raised by the continuous infusion of amino acid, but the significant change was not found between lactaing and non-lactating periods. From these results, we conclude that lactating goats showed exergonic reactions (catabolism) at the maintenance energy level, whereas they did synthetic reactions (anabolism) at the excess energy level. However, further study on the method to increase milk yield remains to be investigated.
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