Analysis of Candidate Genes for Growth and Milk Performance Traits in the Egyptian Barki Sheep

Abstract

The most common sheep breeds of Egypt are Ossimi, Rahmani, and Barki breeds. The latter one is well adapted to the challenging desert environment, characterized by food shortage and a high temperature fluctuation. Growth performance of Barki sheep has an important economic value in terms of minimizing the shortage of mutton meat in Egypt. Further, milk production is of great importance for feeding newborn lambs. Eight candidate genes, recently associated with production traits in different breeds, were used to study the effect of genotype on lamb growth and ewe milk traits. The examined genes were LEP, IGF1, DGAT1, STAT5A, PRL, CSN1S2, GHR, and GHRHR, of which one representative single nucleotide polymorphism (SNP) located in the coding region was selected for genotyping. Data from 251 Barki sheep were used in this study. Association analysis between SNPs and lamb growth traits identified rs420693815 of the LEP gene to be significantly associated with weaning weight and average daily gain. In ewes, significant effects on milk yield and composition have been estimated for LEP (rs420693815), STAT5A (rs161082816), PRL (rs422713690), and GHRHR (rs414991449). The results indicated that these genes might be considered as interesting candidates for further investigations to improve growth and milk performance in Barki sheep.

A missense mutation in the coding region of the toll-like receptor 4 gene affects milk traits in Barki sheep

“…Overall, the estimates of milk traits reported here in Barki ewes were in agreement with those estimated by Abousoliman et al [3] in Barki sheep and dairy sheep in Slovakia [14]. How-ever, some milk components were dissimilar in the Slovakian ewes (FP = 6.91% vs 4.63%, LP = 4.54% vs 6.37%) compared with those reported in this study.…”

“…Additionally, it is more nutritious, richer in vitamins A, B, and E, calcium, phosphorus, potassium and magnesium, and has a health benefit as it contains a higher portion of short and medium fatty acids chains [ 2 ]. On the other hand, it has a positive impact on the newborn lambs, in which good milk supply from the mother may increase the growth rate in the lambs [ 3 ].…”

Genetic Polymorphisms of Fabp4 Gene and Their Association with Milk Traits in Barki Ewes الأنماط الجينيه لجين FABP4 وعلاقتها بصفات اللبن في نعاج البرقي

“…This lower polymorphism may be due to higher selection pressure for the gene in Barki (Zhou et al, 2017;Sallam, 2021), which decreases the genetic variations in the studied individuals in the corresponding genomic region. It could be attributable also to the high similarity of the allelic frequency of FABP4 reported in this study in Barki sheep, due to inbreeding (Abousoliman et al, 2020). Effect of presence/absence of the FABP4 gene variants on the studied traits Effect of presence/absence model of the FABP4 gene variants on milk traits is illustrated in Table 3.…”

“…Globally, milk production is a trait of interest that was under intensive selection for many years in livestock. Alongside to the unique dairy products of sheep for the human consumption, another concern of milk production as the main source to sufficient feed of the newborn lambs (Abousoliman et al, 2020). This is eventually lead to producing healthy lambs until weaning, which is dependent mainly on their dam's milk production and composition (Amel et al, 2019).…”

Genome-Wide Analysis for Early Growth-Related Traits of the Locally Adapted Egyptian Barki Sheep

“…This is also related to the fact that problems for the dam or the newborn lamb should be avoided, such as dystocia during the birth process. In fact, Barki sheep show large differences in growth traits, ranging from 2.4 to 5.0 kg for birth weight with an average of 3.7 kg and from 5.2 to 28.8 kg for weaning weight with an average of 13.8 kg [19]. In general, although Barki sheep are highly adapted to the harsh environmental conditions of northeast Africa and have a high value for farmers in this region, it remains difficult to obtain a large number of genotyped and comprehensively phenotyped animals due to the smallholder sheep farming systems in Egypt [20].…”