| Summary: | 碩士 === 東海大學 === 畜產與生物科技學系 === 97 === Excessive adipose mass has been related to low egg yields in hens. The B and L2 chicken lines were bred from the same group of Taiwan country chickens. The L2 line has high egg yields and low adipose mass compared with the B line. This study aimed to investigate the possible roles of serum factors in the different accretion of adipose tissues observed in these two chicken lines. Three individual experiments were conducted using primary culture of adipose stromal-vascular (S-V) cells. Firstly, sera collected from B or L2 chickens during laying periods were applied to the primary culture of broiler adipose S-V cells and adipose conversions were measured. Cells treated with B line serum showed higher levels of triglyceride content and GPDH activity than those treated with L2 line serum. In addition, RT-PCR analysis showed that the mRNA levels of adipose conversion-related genes were higher in B line serum-treated cells than L2 line serum-treated cells. Secondly, sera of B or L2 chickens in prelaying periods were collected and applied to the primary culture of broiler adipose S-V cells. Adipose S-V cells cultured in L2 serum have high levels of triglyceride content, GPDH activity, and the mRNA expression of adipose conversion-related genes compared with those cultured in B serum. Finally, adipose S-V cells from B or L2 line chickens were treated with sera collected from prelaying B or L2 chickens to confirm the differences of serum adipogenic activities between B and L2 chickens observed in the second experiment. Both B and L2 adipose S-V cells cultured in L2 serum demonstrated higher levels of triglyceride content, GPDH activity, and the mRNA expression of adipose conversion-related genes than those cultured in B serum. Taken together, the serum of B line chickens during laying periods had higher adipogenic activity than L2 line chickens. L2 line serum collected in prelaying periods, however, had high adipogenic activity compared with B line serum. These results suggest that the low adipose mass observed in the L2 line chicken during laying period may be related to its low serum adipogenic activity compared with the B line chicken. On the contrary, higher serum adipogenic activity in prelaying L2 chickens implies that L2 chickens possess the energy management better prepared for the ongoing egg production than B chickens do.
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