Saturated Fatty Acids in Wool as Markers Related to Intramuscular Fat Content in Lambs.

The aim of this study was to identify Longissimus lumborum (LL) muscle from lambs with high IMF content (≥3%) using wool FA. The FA composition was characterized in two sections of wool from Suffolk Down lambs, and its relationship with IMF content assessed. One hundred and forty lambs of similar body weight, body condition score, and age were selected. IMF content from LL muscle, and the wool fat and FA composition of the wool were determined. The proportions of FAs in the wool of lambs with low IMF were 51.96 ± 7.3% of saturated, 31.96 ± 7.7% polyunsaturated, and 16.08 ± 2.3% monounsaturated. Similar proportions of FAs were observed in wool samples of lambs with high IMF. Significant differences were found only in the SFA proportion between groups (p < 0.05). The predominant FAs in the wool samples were C16:0, C17:0, C18:0, C18:1n9c and C18:2n6c, representing over 60% of total FA methyl esters. Correlations were found between the wool FAs C16:1, C17:0, C18:0, C18:1n9c, C24:0, and C22:6n3 in wool samples divided into two sections. Discriminant analysis identified SFAs, particularly FAs C22:0 and C24:0, as potential candidate for predicting lambs with high IMF content with an accuracy of over 92%. These results provide to our knowledge evidence that IMF content could potentially be determined using wool FAs as a non-invasive method.

Characterization of the genetic diversity, structure, and admixture of 7 Chilean chicken breeds.

The Mapuche fowl is an autochthonous breed raised in Chile and represents an important zoogenetic resource for the local economy. This study aimed at investigating the genetic diversity, relationship and population structure of 96 local Chilean chickens derived from 3 ecotype of Mapuche fowl (Kollonka, Ketro, and Kollonka de aretes), 2 ecotype Chilean (Trintre, Cogote pelado) and 2 breeds (Light Brahma and Barred Plymouth Rock) using 12 microsatellite markers. In total, 113 alleles were detected in all populations, with a mean of 7.6 alleles per population. In all population chicken breeds, the observed and expected heterozygosity ranged from 0.91 to 0.98 and from 0.69 to 0.79. Furthermore, all populations showed significant deviations from Hardy-Weinberg expectations. Across each population, the global heterozygosity deficit (FIT) was -0.174, population differentiation index (FST) was 0.073, and the global inbreeding of individuals within breed (FIS) was -0.267. The phylogenetic relationships of chickens were examined using neighbor-joining trees constructed at the level of population. The highest Nei's standard genetic distance value of 0.559 was observed between Barred Plymouth Rock and Light Brahma, whereas the minimum value (0.099) was found between Kollonka and Trintre. The neighbor-joining tree constructed at population level revealed 2 main clusters, with Light Brahma, Barred Plymouth Rock, Ketro and Kollonka de aretes in 1 cluster, and Kollonka, Trintre and Cogote pelado breeds in the second cluster. Based on the results of the STRUCTURE analysis, the most likely number of clustering of the population evaluated was at K = 3, with Light Brahma and Barred Plymouth Rock breeds forming their own distinct clusters, while Kollonka, Ketro, Kollonka de aretes, Trintre and Cogote pelado breeds clustered together. This study represents the first report of genetic diversity in these populations in Chile. These results can be used as baseline genetic information for genetic conservation program, for instance, to control inbreeding and to implement further genetic studies in local Chilean chickens.