Abstract: The growth hormone (GH) and growth hormone releasing hormone (GHRH) contents in serum of 3 weights (90,110 and 130 kg) of Chuanzang Black swine hybrid and DLY pigs were detected by enzyme-linked immune sorbent assay (ELISA),their relationship with cross sectional area of muscle fiber (CSA) and intramuscular fat (IMF) content were also analyzed.The results showed that the GH contents of Chuanzang Black swine hybrid and DLY pigs of 3 weights were 14.25,14.61,14.11 and 17.86,16.98,16.77 μg/L,respectively,while the GHRH contents of which were 22.88,23.98,24.33 and 27.72,27.47,28.39 μg/L,respectively.There was no significant difference in different weight of the same breeds (P >0.05) except the significant difference between 90 and 130 kg of DLY pigs (P<0.05).The GH and GHRH contents of Chuanzang Black swine hybrid were both significant lower than DLY pigs of the same bodyweight (P< 0.05) except GHRH content of 110 kg weight (P >0.05).Relevance analysis showed that GH and GHRH contents had a significant positive correlation with CSA (P< 0.05),and an extremely significant negative correlation with IMF content (P< 0.01),which prompted that GH and GHRH might regulate the growth of muscle fiber and IMF deposition through blood.

Key words: Chuanzang Black swine hybrid; DLY; cross sectional area of muscle fiber (CSA); intramuscular fat (IMF); growth hormone (GH); growth hormone releasing hormone (GHRH)