ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2011, Vol. 42 ›› Issue (1): 39-43.doi:

• 动物营养 • Previous Articles     Next Articles

The Effects of Injecting pGRF Gene Plasmid on Growth Axis Hormones in the Growing Pigs

ZHANG Jin-xia1, 2, ZHANG Hong-fu1*,ZHOU Zhan-qin2，LIU Yu-tian1,2, LIU Sheng-jun1,WEI Xing-hui3, DING Guo-qing3   

  1. 1. State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China； 2.College of Animal Science and Technolgy, Northwest Agriculture and Forestry University, Yangling 712100, China; 3.Greenpak Biotech of Hong Kong, Hong Kong 999077, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2011-01-25 Published:2011-01-25

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Abstract: This study was conducted to investigate the effect of pig growth hormonereleasing factor gene plasmid （pGRF) on the change of growth axis-hormones in growing pigs by injecting. Eight crossbred castrated boar pigs (Landrace ×Large white) with similar weight((15±0.43)kg) were allocated into two treatments, the experimental and control groups. The experimental pigs was injected with 2 mL (4.5 mg) pGRF at neck, and the control ones were done in the same way with 2 mL normal saline. Serum samples were taken from all pigs at days 1, 4, 7, 11, 16, 21, 26 and 31 after injecting, and the levels of serum GH，IGF-Ⅰ，GRF and SS were determined. The results showed that the serum GH level of pigs in the experimental group increased significantly by 113.47% （P<0.01) compared with the control pigs at day 7 after injecting. Then the values declined gradually, it increased by 47.09% （P<0.05) at day 11 after injecting, and there was no significant difference at day 31. The serum IGF-Ⅰand GRF levels of the experimental pigs had no obvious increase, but they correlated significantly with serum GH level. The correlation coefficient were respectively 0.589（P<0.05) and 0.678 （P <0.05). Their peaks appeared also at day 7 and then declined gradually Compared to the control pigs, the serum SS concentrations in experimental pigs shown a downward trend before day 11 (they reached the lowest point at day 11), but they ascended at day 16 and declined slowly after that, they declined to the same level as that of control pigs at day 31. There were significant negative correlation among the serum SS and GH and GRF levels，the correlation coefficient were respectively －0.777（P<0.01) and －0.689（P<0.05). It can be seen, pGRF gene plasmid could express in vivo and promote the secretion of GH by improving the serum content of GRF. The secretion of SS was inhibited by the injection, which meant the inhibition of GRF and GH by SS was decreased to a certain degree. It suggested that pGRF gene plasmid could play a growth-promoting role in the pigs. In the same time, we found that although the blood samples were taken from pigs by venous fistula, the variances of the determined data on hormones were still big, so increasing the number of experimental pigs was necessary for the better objective results