Prevalence of αs1-casein genotypes in American dairy goats1

Abstract

Widespread genotyping of US dairy goat breeds for casein variants has not been reported, even though the genetic data could be of use in selective breeding programs. For instance, variability in the content of protein and solids in goat milk is attributed to allelic differences in the goat alpha(s1)-casein gene. Concentrations of alpha(s1)-casein in goat milk are positively correlated with milk components and coagulation properties. The alleles A and B are designated as strong alleles, resulting in the greatest amount of alpha(s1)-casein in goat milk, whereas the E allele produces intermediate amounts and the weak allele F produces the least concentrations of alpha(s1)-casein in goat milk. Here we report on one of the first surveys of the distribution of alpha(s1)-casein genotypes in US dairy goats. The population surveyed, consisting of a total of 257 American dairy goats representing 7 main dairy breeds, contained a greater predominance of the weaker alleles, E and F, than the strong alleles, A and B. Allele distribution was related to breed, with Toggenburg, Alpine, Saanen, and Oberhasli containing the most E and F alleles and LaMancha, Nubian, and Nigerian Dwarf the fewest. Quantification of alpha(s1)-casein production by 2-dimensional gel electrophoresis demonstrated that F/F animals had the least amount of alpha(s1)-casein protein in their milk compared with all other genotypes. The results indicate that genetic improvement of dairy goats in the United States could be achieved if an alpha(s1)-casein breeding scheme were adopted.

Genetic polymorphism at the CSN1S1 gene in Girgentana dairy goat breed

“…Moreover, casein concentration is greater when strong alleles are present . Maga et al (2009) in a study conducted on the as 1 -casein content in American dairy goats, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional gels, showed that milk from FF and EE animals had 35 and 25% less caseins, respectively, than animals homozygous for the strong alleles. The presence of A or B allele in heterozygote condition with either the F or E allele reduced the deficit in casein by only 5-7% compared with AA homozygote condition.…”

“…Allele E was absent in other goat breeds reared in Southern Italy and showed low frequency in Maltese (Gigli et al 2008) and in Sarda goat breeds (Dettori et al 2009). Furthermore, while the strong alleles appeared more frequently in the autochthonous goat population reared in Southern Italy, allele E was more frequent in Spanish (Jordana et al 1996), French (Ramunno et al 1994) and American (Maga et al 2009) goat breeds. For the A and F alleles, Marletta et al (2005) reported frequency values similar to our results (A = 0.600 vs 0.590, F = 0.040 vs 0.047).…”

Consumption of Lysozyme-Rich Milk Can Alter Microbial Fecal Populations

“…Milk was collected at peak lactation (2 months) from two transgenic animals each in their 1st, 2nd, and 3rd lactations and equal numbers of breed-and parity-matched nontransgenic controls. A total of 200 g of protein from each milk sample was subjected to 2-D gel analysis followed by matrix-assisted laser desorption ionization-time of flight/time of flight (MALDI-TOF/TOF) mass spectrometry as previously described (32). Briefly, separation in the first dimension by isoelectric point was carried out using Immobiline DryStrips (GE Healthcare, Piscataway, NJ) (pH 3 to 5.6; 11 cm in length) followed by separation in the second dimension by size on 15% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels (Protean Xi; Bio-Rad, Hercules, CA).…”

Comparative Protein Composition Analysis of Goat Milk Produced by the Alpine and Saanen Breeds in Northeastern Brazil and Related Antibacterial Activities

“…The interspecies differences can be evaluated using proteomic analysis; however, studies evaluating the nitrogen profile and protein fractions of milk from different breeds of the same species, particularly among goat breeds, are still scarce [13], [14], [15]. In this context, studies with an emphasis on the comparative proteomic evaluation of goat milks are important to identify their protein fraction; these studies will help characterize the alternative hypoallergenic protein sources or protein sources that have important technological properties for processing, leading to the preparation of products with added value.…”