A Tool for Sheep Product Quality: Custom Microarray from Public Databases

Milk and dairy products are an essential food and an economic resource in many countries. Milk component synthesis and secretion by the mammary gland involve expression of a large number of genes whose nutritional regulation remains poorly defined. We aim at understanding the genomic influence on milk quality and synthesis by comparing two sheep breeds, with different milking attitude, Sarda and Gentile di Puglia, using sheep-specific microarray technology. From sheep ESTs deposited at NCBI, we generated the first annotated microarray developed for sheep with a covering of most of the genome. Whole tissue samples of mammary gland were collected from 4 lactating individuals of two sheep (Ovis aries) breeds, Gentile di Puglia and Sarda. Biopsies of lactating mammary tissue were taken at two lactation stages (first record, stage 01: 6 days after lambing; second record, stage 02: 44 days after lambing) in both breeds. Tissues from mammary gland were immersed in RNAlater (Sigma) immediately after biopsy and stored at -20°C.