The Effects of Somatotropin Passive Immunization on Milk Yield, Plasma Hormone and Metabolite Concentrations in Rats

The objectives of this study were to measure growth rate and endocrine changes and to improve milk production by somatostatin passive immunization in rat. Experimental animals were 10 weeks old 20 Sprague-Dawley rats. The rats were randomly assigned each 10 in control (normal sheep serum injected: NSS) and treatment (anti-somatostatin injected), and pre-fed for 2 weeks. Anti-somatostatin was purified from serum of 1 year old sheep after somatostatin active immunization, and was injected daily to rats, and growth rate and milk yield were measured for 14 days. Growth rate of litters was 2.15 g/d and 2.32 g/d in NSS and anti-somatostatin injected, respectively. Milk production was increased 6.2% in day 8 and 6.5% in day 12 by anti-somatostatin injection. Plasma growth hormone, insulin, glucose, and urea-N were increased, but non-esterified fatty acid was decreased by anti-somatostatin injection. In summary, passive immunization of somatostatin improved growth rate of litters and milk production in rats.