Detección genómica y expresión de péptidos antimicrobianos (α- y β-defensinas) en mucosa intestinal de crías de alpaca (Vicugna pacos)

The aim of this study was to determine the presence of genomic β-and α-defensins (bovine enteric beta defensin - β-def alp - and Defa 8 respectively) and their levels of expression as messenger RNA in samples of intestinal mucosa of newborn alpacas. Samples of jejunum of 30 animals from 0 to 45 days of age were collected. Genomic DNA and mRNA were extracted for PCR analysis and real-time RT-PCR respectively. All samples amplified a single DNA segment (between 800 and 900 pb) by PCR which corresponds to the alpha defensin 8 (defa 8), while 90% (27/30) amplified a segment expected 300-350 pb for β-def alp and two additional bands of 800-900 pb evidenced by agarose gel electrophoresis. The detection of mRNAs by real time RT-PCR was performed based on Cycle threshold (Ct) analysis and Melting temperature (Tm) of the amplified products. The Cts for defa 8 products were found between 25.1 and 39.5 cycles with an average of 36.4 ± 1.9, and the Tm of the amplicons was located between 79.1 and 85.7 °C. The Cts for β-def alp were found between 22.7 and 36.8 cycles with an average of 32.4 ± 3.3 and the Tm of these amplified products ranged between 71 and 81.9 °C. The expression levels were determined by relative quantification based on the comparative Ct method. The results showed increased levels of defa 8 and β-def alp until the 3 ^rd week of age, and a decline between the 4^th and 6 ^th week of age. The results demonstrate the genomic presence and expression of α- and β-defensins in the jejunum of alpacas younger than 45 days old.