Effect of a novel somatostatin-14 DNA vaccine fused to tPA signal peptide and CpG adjuvant on goat lactation and milk composition.

• Immunization of SS DNA vaccine fused to tPA and CpG induced strong antibody response. • Immunization of SS DNA vaccine increased serum PRL and GH levels. • SS gene immunization improved goat lactation and milk protein and lactose. • The effect of SS DNA vaccine was related to the roles of GH and PRL. This study aimed to investigate the effect of a novel oral somatostatin-14 (SS-14) DNA vaccine fused to tissue plasminogen activator (tPA) signal peptide and CpG adjuvant on goat lactation and milk composition. Ten female goats with two newborn kids each were randomly divided into the immunized group and negative control group; The novel oral somatostatin (SS) DNA vaccine (fused to tPA signal peptide and CpG adjuvant) and empty vector bacteria were orally administered to these groups, respectively, at weeks 0, 3, and 6 of the study period. Blood samples were collected before primary immunization and at weeks 6 and 9 after primary immunization. The specific anti-SS antibody titers in the immunized group were significantly higher than that in the negative control group (P < 0.05). Serum SS concentration was significantly lower, whereas growth hormone (GH) and prolactin (PRL) concentrations were significantly higher in the immunized group compared with those in the negative control group (P < 0.05). Meanwhile, the weight of the kids and the milk protein and lactose contents of the goats were significantly higher in the immunized group than those in the negative control group at week 6 of lactation (P < 0.05). The study revealed that the novel oral SS DNA vaccine can increase serum GH and PRL levels and effectively promote goat lactation and milk composition. This finding indicated a correlation between the effect of SS-14 DNA vaccine treatment and the roles of GH and PRL. [ABSTRACT FROM AUTHOR]