PARENT SESSION

(W477) IMPLICATION OF ADIPOGENESIS ON REPRODUCTION IN SOW; NEW CANDIDATE GENES?

Labrecque, Benoit¹, Murphy, Bruce¹, Mathieu, Olivier², Palin, Marie-France ², ¹ University of Montreal, St-Hyacinthe, QC, Canada² Dairy and Swine Research and Development Centre, AAFC, Lennoxville, QC, Canada

ABSTRACT- The adipose tissue is an important endocrine organ, producing factors that act on the hypothalamus and peripheral tissues to regulate a number of processes, including reproduction. The importance of body fat to the maintenance of estrous cycle and lifetime reproductive rate has been demonstrated in mammals. For example, lean sows (<14 mm of backfat at selection) produce fewer litters over their lifetimes than fatter sows. Moreover, reproductive performances in the second pregnancy of lean sows are often poor, with delayed returns to estrus and low litter size. Our working hypothesis is that some adipose derived factors are key regulators of reproductive processes in the pig. The objective of that study was to identify new candidate genes that are produced during the terminal differentiation of fat cells, and that could have a key role in swine reproductive traits. The subtractive suppressive hybridization (SSH) technique was used to identify differentially expressed genes between fully differentiated fat cells from subcutaneaous fat of an adult sow and preadipocytes collected from fetal pigs (Day 90 of pregnancy). The SSH libraries were performed with the PCR-Select cDNA Subtraction Kit, followed by a differential screening using the PCR-Select Subtraction Hybridization Screening Kit (Clontech, Palo Alto, CA). DNA sequencing was performed on differentially expressed clones and sequences were compared against the GenBank database using online computer BLAST program. Differentially expressed clones were classified into different categories according to their sequence identities with GenBank database. Sixty-six cDNA were considered as identified genes based on their high similarities with Genbank sequences, 61 cDNA were similar to EST sequences and 25 new cDNA sequences that had no significant similarity to any GenBank entry. Multi tissues analyses were also performed in order to characterize the gene expression profiles of novel and identified cDNA in various tissues. Further characterization of differentially expressed cDNA will be needed in ovarian and uterine tissues from animals under various reproductive conditions before being able to identify adipose derived factors with key roles in reproductive functions.

KEY WORDS: Gene Expression, Pig, Adipogenesis, Reproductive Functions