Fatty Acid Composition of the Mammary Gland of Majorera and Palmera Goat Breeds Subject to Undernutrition
Susana P. Alves1, A. Cabo1, L.E. Hernández-Castellano2,3, N. Castro2, A. Arguëllo2, J. Capote4, R.J.B. Bessa1, A. Almeida1,5,6
1CIISA, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal, 2Universidad de Las Palmas de Gran Canaria, Arucas, Spain, 3Vetsuisse Faculty, University of Bern, Bern, Switzerland, 4ICIA, Instituto Canario de Investigaciones Agrarias, Tenerife, Spain, 5Instituto de Investigacao Cientifica Tropical, and Instituto de Biologia Experimental e Tecnologica, Portugal, 6Present Address: Ross University School of Veterinary Medicine, St. Kitts and Nevis, West Indies

Milk production and goat´s body condition are severely depressed during the dry season in Tropics due to the scarcity of pastures. Goat breeds vary in their tolerance to the seasonal feed scarcity and body weight loss, thus it would be possible to identify physiological markers of this trait. Two goat breed differing in their adaptation to dry season (Majorera - well adapted, and Palmera - non adapted) were submitted to moderate feed restriction and the lipid content and fatty acid (FA) composition of mammary gland tissue were compared. Nine Majorera and 10 Palmera goats in mid lactation were divided into control and feed restrition (FR) groups with FR animals loosing 15% of their initial live weight in 23 days of the trial. At the 23th day, mammary gland biopsies were conducted, the total lipids were extracted and FA were determined by GC-FID. Data were analyzed as 2-way ANOVA and statistical significance was declared at P<0.05. FR reduced the FA content in both breeds but the reduction in total lipids were not significant. FR reduced the proportion of 12:0, 14:0, 17:1c9, 18:3n-3, 18:2c9,t11 and increased the 20:4n-6 in both breeds. A significant breed x FR interaction was detected for 16:0 and 18:1c9. The 16:0 decreased with FR from 27 to 20 wt% in Palmera goat compared with Majorera (24 to 21 wt%). Similarly, the 18:1c9 decreased from 44 to 30 wt% in Palmera compared to the non significant decrease (41 to 36 wt%) in Majorera. In spite of the overall effect of FR in reducing the total FA content of mammary gland tissues, the Palmera goats display a deeper change in the FA profile than the Majorera, well adapted to seasonal dryness and pasture shortage.
Financial support though the grant (PTDC/CVT/116499/2010) and fellowships to S.P. Alves (SFRH/BPD/76836/2011) from FCT are acknowledged.