Genome-wide analysis identified candidate variants and genes associated with heat stress adaptation in Egyptian sheep breeds

Heat stress caused by climatic changes is one of the most significant stresses on livestock in hot and dry areas. It has particularly adverse effects on the ability of the breed to maintain homeothermy. Developing countries are advised to protect and prepare their animal resources in the face of potential threats such as climate change. The current study was conducted in Egypt’s three hot and dry agro-ecological zones. Three local sheep breeds (Saidi, Wahati, and Barki) were studied with a total of 206 ewes. The animals were exercised under natural heat stress. The heat tolerance index of the animals was calculated to identify animals with high and low heat tolerance based on their response to meteorological and physiological parameters. Genomic variation in these breeds was assessed using 64,756 single nucleotide polymorphic markers (SNPs). From the perspective of comparative adaptability to harsh conditions, our objective was to investigate the genomic structure that might control the adaptability of local sheep breeds to environmental stress under hot and dry conditions. In addition, indices of population structure and diversity of local breeds were examined. Measures of genetic diversity showed a significant influence of breed and location on populations. The standardized index of association (rbarD) ranged from 0.0012 (Dakhla) to 0.026 (Assuit), while for the breed, they ranged from 0.004 (Wahati) to 0.0103 (Saidi). The index of association analysis (Ia) ranged from 1.42 (Dakhla) to 35.88 (Assuit) by location and from 6.58 (Wahati) to 15.36 (Saidi) by breed. The most significant SNPs associated with heat tolerance were found in the MYO5A, PRKG1, GSTCD, and RTN1 genes (p ≤ 0.0001). MYO5A produces a protein widely distributed in the melanin-producing neural crest of the skin. Genetic association between genetic and phenotypic variations showed that OAR1_18300122.1, located in ST3GAL3, had the greatest positive effect on heat tolerance. Genome-wide association analysis identified SNPs associated with heat tolerance in the PLCB1, STEAP3, KSR2, UNC13C, PEBP4, and GPAT2 genes

Performance démographique des races locales ovines et caprines dans deux zones agro-écologique de l’Égypte.

International audienceSmall breeders in Egypt raise locally adapted sheep and goats breeds, which have the ability to produce and reproduce under the prevailing harsh conditions. Improving resilience of their production system is a major challenge to support socioeconomic development. However, little is known about the productive abilities of these breeds in small farming systems. The present work is anattempt to assess the performance of local breeds in small farming systems, and their capacity to cope with feed scarcity and harsh climatic conditions. In 2018, a retrospective survey was conducted over 12 month period to assess demographic rates of 25 local Barki sheep and goat flocks in the rain-fed area of Coastal Zone of Western Desert (CZWD) and 28 local Saidi sheep and goat flocksunder the hot intensive agriculture system in Upper Egypt (UE). Flocks are larger, reproductive performance and offtake rates are higher (and mortality lower) in the CZWD, a region specialized in small ruminant breeding whereas it remains a secondary activity in Upper Egypt. The marketing season is mainly during Korban Eid festival. Their main challenges are frequent incidence of drought inthe CZWD and high prices of feed stuffs in both sites. Our study suggests breeders have different strategies in UE and the CZWD when confronted with feed shortage. Breeders in the CZWD purchase feed to maintain high herd productivity whereas in UE small ruminant breeding is a minor activity with less productive animals that are resilient to feed shortage.Les races locales de petits ruminants élevées en Egypte sont reconnues pour leur la capacité à demeurer productives malgré des conditions climatiques extrêmes. L’amélioration de la résilience des systèmes d’élevage est un défi majeur pour le développement socioéconomique. Cependant, les performances démographiques de ces races n’ont à ce jour pas été caractériséesen conditions réelles. Ce travail présente les premiers résultats d’une étude sur les performances de ces races dans deux régions d’élevage contrastées en Egypte. En 2018, des enquêtes démographiques rétrospectives sur les 12 derniers mois ont été effectuées sur 25 troupeaux de moutons et chèvres Barki dans la zone pastorale côtières et sur 28 troupeaux de moutons et de chèvres Saidi lelong de la vallée du Nil en Haute Egypte, une région historique d’agriculture intensive. La fertilité et les taux d’exploitations sont plus élevés en zone pastorale (et la mortalité moindre) vraisemblablement en raison de la spécialisation de cette région dans l’élevage alors qu’il s’agit d’une activité secondaire en Haute Egypte. Le gros des ventes se déroule pendant les fêtes religieuses de KorbanEid. Les principaux défis sont la récurrence des sécheresses dans la zone pastorale et les coûts élevés des aliments dans les deux sites. Nos résultats suggèrent une stratégie différente des éleveurs confrontés au manque de fourrage. Dans la zone pastorale côtière, les éleveurs maintiennent la productivité du troupeau en achetant de l’aliment tandis qu’en Haute Egypte l’élevage de petits ruminantsest une activité mineure avec des animaux moins productifs mais résilient au manque de fourrage

DataSheet1_Genome-wide analysis identified candidate variants and genes associated with heat stress adaptation in Egyptian sheep breeds.PDF

Heat stress caused by climatic changes is one of the most significant stresses on livestock in hot and dry areas. It has particularly adverse effects on the ability of the breed to maintain homeothermy. Developing countries are advised to protect and prepare their animal resources in the face of potential threats such as climate change. The current study was conducted in Egypt’s three hot and dry agro-ecological zones. Three local sheep breeds (Saidi, Wahati, and Barki) were studied with a total of 206 ewes. The animals were exercised under natural heat stress. The heat tolerance index of the animals was calculated to identify animals with high and low heat tolerance based on their response to meteorological and physiological parameters. Genomic variation in these breeds was assessed using 64,756 single nucleotide polymorphic markers (SNPs). From the perspective of comparative adaptability to harsh conditions, our objective was to investigate the genomic structure that might control the adaptability of local sheep breeds to environmental stress under hot and dry conditions. In addition, indices of population structure and diversity of local breeds were examined. Measures of genetic diversity showed a significant influence of breed and location on populations. The standardized index of association (rbarD) ranged from 0.0012 (Dakhla) to 0.026 (Assuit), while for the breed, they ranged from 0.004 (Wahati) to 0.0103 (Saidi). The index of association analysis (Ia) ranged from 1.42 (Dakhla) to 35.88 (Assuit) by location and from 6.58 (Wahati) to 15.36 (Saidi) by breed. The most significant SNPs associated with heat tolerance were found in the MYO5A, PRKG1, GSTCD, and RTN1 genes (p ≤ 0.0001). MYO5A produces a protein widely distributed in the melanin-producing neural crest of the skin. Genetic association between genetic and phenotypic variations showed that OAR1_18300122.1, located in ST3GAL3, had the greatest positive effect on heat tolerance. Genome-wide association analysis identified SNPs associated with heat tolerance in the PLCB1, STEAP3, KSR2, UNC13C, PEBP4, and GPAT2 genes.</p