| 1 Neuroendocrine regulation of Porcine Adipose Tissue DevelopmentIn order to research the neuroendocrine and molecular mechanisms of adipose tissue development, purebred male and female Erhualian pigs, male Large White pigs with significant differences in growth rate, fat deposition and reproductive performance were employed in present study to investigate the developmental changes of GH-R, IGF-1, IGF-IR and Leptin mRNA expression in dorsal subcutaneous adipose tissue and Ob-Rb mRNA expression in hypothalamus by RT-PCR with 18S rRNA as internal standard. Breed difference and sexual dimorphism of the expression patterns of above mentioned genes were also investigated in this research.Results showed that the GH-R, IGF-1 and IGF-IR mRNA expression in adipose tissue followed specific developmental pattern. The developmental change of IGF-1 and IGF-IR mRNA were similar, but were different to that of GH-R. The expression of IGF-1 mRNA were breed different and sexual dimorphic, which was higher in Erhualian boars than in Large White boars, and higher in Erhualian boars than in gilts. The GH-R mRNA expression was higher in Erhualian boars than in Large White boars. The results suggest that the IGF-1 mRNA expression in adipose tissue may independent or partly dependent with GH, and the different patterns of GH-R and IGF-1 gene expression between two breeds may contribute to different phenotypes in adipose tissue deposition.Leptin mRNA expression in adipose tissue increased with age and displayed both sex and line differences. In Erhualian pigs, females expressed higher Leptin mRNA compared with males, and Erhualian boars showed higher abundance of Leptin mRNA than Large White boars. Serum Leptin levels were in good agreement with adipose Leptin mRNA, displaying similar sex and line differences. In contrast, expression of Ob-Rb mRNA in hypothalamus exhibited a distinctive pattern, decreased gradually after birth, and then increased till weaning. After weaning, Ob-Rb gene expression decreased gradually with age but raisedgradually again from 120 to 180 days of age in Erhualian pigs. The expression of Ob-Rb mRNA was higher in Large White pigs than that in Erhualian pigs (P<0.01). The results suggest that the serum Leptin level and Leptin gene expression in adipose tissue highly correlate with adiposity, while Ob-Rb gene expression in hypothalamus is more related with reproductive traits.2 Regulation of porcine adipose tissue by physiological regulators and mechanisms involvedGH can decrease adipose tissue depots, but its mechanism is not yet clear. The relative abundance of GH-R, IGF-1 and IGF-IR mRNA in adipose tissue of growing pigs were increased significantly by rpGH administration, while the expression of Leptin mRNA in adipose tissue were decreased. These results suggest that rpGH could not only regulate adipose tissue directly, but also through the mediation of enhanced IGF-1 secretion in adipose tissue, act locally via the IGF-IR in an autbcrine/paracrine manner.The functional component of CT2000 is cysteamine-a somatostatin inhibiting agent, which can promote growth in animals. However, the effect of cysteamine on adipose tissue depots is not very clear. CT2000 treatment enhanced the body weight gain of finishing pigs, decreased the adiposity index and back-fat thickness in 6,7 rib, decreased the serum Leptin concentration, increased serum TNF- a . CT2000 also down-regulated the relative abundance of Leptin mRNA in dorsal subcutaneous adipose tissue (p<0.05). But no difference in serum insulin level, the relative abundance of GH-R, IGF-1, IGF-IR mRNA in dorsal subcutaneous adipose tissue and Ob-Rb mRNA at hypothalamus between CT2000 treated and control group was found. These suggest that CT2000 can improve carcass quality of finishing pigs apart from its growth-promoting action.3 Effect of yolk antibody against pig adipocyte plasma membrane (APM) protein on adipose tissue depositionImmunization against APM can reduce body fat deposition and improve carcass quality. Anti-sera have b...
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