Suckling lamb perirenal fat transcriptome

The aim of this study was to perform a comparative analysis of the perirenal fat transcriptomes of suckling lambs from two breeds with different growth and carcass characteristics. The perirenal fat tissue from 14 suckling lambs (Assaf= 8, Churra= 6) was used for the RNA-Seq analysis. The functional enrichment analysis of the 670 highly expressed genes (>150 fragments per kilobase of exon per million fragments mapped) in the perirenal fat transcriptome of both breeds revealed that the majority of these genes were involved in energy processes. The differential expression analysis performed identified 373 differentially expressed genes (DEGs) between the two compared breeds. In Assaf lambs, DEGs were enriched in Gene Ontology (GO) biological processes related to fatty-acid oxidation, while in Churra lambs, the majority of the significantly enriched GO terms were related to cholesterol synthesis, which suggests that upregulated DEGs in Assaf lambs are implicated in fat burning, while the Churra upregulated DEGs are linked to fat accumulation. The transcriptome analysis was performed with RNA extracted from perirenal adipose tissue from 14 suckling lambs from two different breeds (specifically, six Churra and eight Assaf lambs). All the lambs included in this study were males born between April and May 2016. After birth, lambs were maintained between 4-8 hours with their dams to suck the first colostrum. Then, in order to avoid the maternal effects, they were held in lamb pens and fed Ovilac 60 (Calfvet, Lleida, Cataluña, Spain) milk replacer powder using a milk replacer machine. Lambs were slaughtered when they reached an average live weight of (mean ± SD) 10.32 ± 0.73 kg, which is the common market weight range. Lambs ages at slaughter were from 19 to 35 days old, and carcass weight for Churra and Assaf lambs were 5.16 ± 0.44 and 5.34 ± 0.33 kg, respectively. The management, transport and sacrifice of the animals was in accordance with the Spanish and EU legislations (Spanish Laws 32/2007, 6/2013 and RD 37/2014; Council Regulation (EC) 199/2009). At slaughter, perirenal adipose tissue was collected from each lamb.