Heterozygosity analysis of Bionda Piemontese and Bianca di Saluzzo chicken breeds by microsatellites markers: a preliminary study

Effects of Saccharides Supplementation in the Extender of Cryopreserved Rooster (Gallus domesticus) Semen on the Fertility of Frozen/Thawed Spermatozoa

The aim of this study was to create balanced media for the cryopreservation of rooster semen in pellets to maintain the functional state of the sperm after thawing. Fructose was replaced by trehalose in experimental media in proportions of 10% (LCM-T10) and 20% (LCM-T20), while LCM was used as a control. After artificial insemination of the hens, the eggs were incubated (n = 400). To determine the functional safety of spermatozoa in the genital tract of hens after 5, 10, and 15 days from the last insemination, we used a method for assessing the interaction of sperm with the perivitelline membrane. Significantly higher rates of egg fertilization (82-86%) were obtained when using LCM-T10 and LCM-T20 compared to control (79%, p < 0.05). Egg fertility on the 5th day from the last insemination with the LCM-T20 diluent reached 100% versus 86% in the control; on the 10th day, the fertility rates were 55% versus 20%, respectively. The best results for fertility duration were obtained by freezing spermatozoa with LCM-T20 medium. The numbers of interaction points of spermatozoa with the perivitelline membrane were as follows: on the 5th day from the last insemination with LCM-T20-461.5 ± 11.5 holes/cm² (LCM-control-13.7 ± 2.7 holes/cm²), p < 0.01; on the 10th day with LCM-T20-319.3 ± 12.9 holes/cm² (LCM-control-14.9 ± 3.5 holes/cm²); and on the 15th day with LCM-T20-345.2 ± 11.1 holes/cm² (LCM-control-0 holes/cm²). In conclusion, the use of trehalose in LCM diluent medium can increase the fertility of frozen/thawed sperm and the duration of their fertility in the genital tract of hens.

Authentication of poultry products at the breed level using genetic markers

The Oravka tawny is a Slovak national breed of chicken. This breed has combined utility, which means it is valuable for both its meat and eggs. The Oravka tawny is linked to a specific region, Orava, and therefore these products could be protected by European geographical indication. The labeling and sale of chicken meat by the traditional breed of origin are widely used to promote quality and attract those products in the marketplace. For that use, we created the system and method of authentication that can reliably distinguish between the Oravka tawny, other chicken breeds, and other of Oravka”™s colorful characters. In our research, we analyzed 153 chicken feathers from the Oravka breed as well as from breeds used in the process of breeding the Oravka to their current state. They were divided into nine populations. To separate those populations, we used seven microsatellite markers recommended by FAO (Food and Agriculture Organization) and other authors. To create separate clusters of individual breeds, we used DAPC (discriminant analysis of principal components) analysis.

Looking at genetic structure and selection signatures of the Mexican chicken population using single nucleotide polymorphism markers

Genetic variation enables both adaptive evolutionary changes and artificial selection. Genetic makeup of populations is the result of a long-term process of selection and adaptation to specific environments and ecosystems. The aim of this study was to characterize the genetic variability of México's chicken population to reveal any underlying population structure. A total of 213 chickens were sampled in different rural production units located in 25 states of México. Genotypes were obtained using the Affymetrix Axiom® 600 K Chicken Genotyping Array. The Identity by Descent (IBD) and the principal components analysis (PCA) were performed by SVS software on pruned single nucleotide polymorphisms (SNPs).ADMIXTURE analyses identified 3 ancestors and the proportion of the genetic contribution of each of them has been determined in each individual. The results of the Neighbor-Joining (NJ) analysis resulted consistent with those obtained by the PCA. All methods utilized in this study did not allow a classification of Mexican chicken in distinct clusters or groups. A total of 3,059 run of homozygosity (ROH) were identified and, being mainly short in length (<4 Mb), these regions are indicative of a low inbreeding level in the population. Finally, findings from the ROH analysis indicated the presence of natural selective pressure in the population of Mexican chicken.The study indicates that the Mexican chicken clearly appear to be a unique creole chicken population that was not subjected to a specific artificial selection. Results provide a genetic knowledge that can be used as a basis for the genetic management of a unique and very large creole population, especially in the view of using it in production of hybrids to increase the productivity and economic revenue of family farming agriculture, which is widely present in México.

Genetic variability of two Italian indigenous chicken breeds inferred from microsatellite marker analysis

The objective of this study was to determine the genetic structure and variability of Bionda Piemontese and Bianca di Saluzzo (Piedmont, Northwest Italy) using an international set of microsatellite loci (AVIANDIV-FAO). Differences compared with commercial lines and other Italian breeds were verified to justify the implementation of conservation programmes. Flock contribution to genetic variability was assessed following the approach implemented in the MolKin software. Comparison was performed using the fixation index and the Reynolds genetic distance. The most likely number of different populations was estimated using the clustering procedure implemented in STRUCTURE. The molecular information suggests that management practices could have prevented random mating and produced inbreeding and heterogeneity across flocks. In this respect, Bionda and Bianca show substructuring and are more similar to British breeds than other continental European breeds. Bionda and Bianca fit into the European breeds provided with the highest number of alleles and expected heterozygosity. There is a clear distinction between the Piedmont breeds and the other populations. The Piedmont poultry differ from both commercial lines and other Italian breeds and retain a high level of genetic variability. As for other indigenous breeds, Bionda and Bianca could make an original contribution to the industry in the future. A collective planned approach to restoration is essential, because the flocks are managed with poor regulation. Enhancing connection between breeders with an efficient replacement interchange and mating plan is the right way of controlling inbreeding, preventing substructuring and increasing variability within the flocks.