A Comparative Study of Sheep Breeds: Fattening Performance, Carcass Characteristics, Meat Chemical Composition and Quality Attributes

Fattening performance, Carcass characteristics, chemical composition, and meat quality were evaluated in three sheep breeds: Awassi, Harri, and Najdi. Forty-five lambs of similar weight and age were raised for 90 days under similar conditions. The Harri and Najdi breeds had higher dressing-out percentages than Awassi sheep. The Awassi and Harri breeds had thicker backfat than the Najdi breed. No significant difference was found in moisture, protein, and intramuscular fat among the breeds. However, the Harri breed had a higher ash content than the Awassi and Najdi breeds. The Najdi breed had higher ultimate pH and lower cooking loss than the Awassi and Harri breeds. Awassi and Harri sheep had a higher myofibril fragmentation index, longer sarcomere length, and lower hardness and chewiness than Najdi sheep. Subjectively, no significant differences were detected between the breeds, except for flavor intensity while the Awassi sheep were rated in between and not significantly different. In conclusion, breed affected carcass characteristics, meat composition, and the quality of sheep. The dressing yield was higher in Harri and Najdi than Awassi sheep. Awassi sheep showed superior meat quality characteristics followed by Harri sheep. However, Najdi sheep had the best cooking loss percentage and flavor intensity score.

Gene Expression and In Vitro Maturation of Sheep Oocytes using Bee Pollen and Bee Honey as Medium Supplements

This study was conducted to investigate the effects of raw honey obtained from black seed or Sider and honeybee pollen as an additive in sheep oocyte maturation medium on the oocyte maturation rate, changes in oocyte glutathione (GSH) levels and expression of developmental candidate genes (GDF-9, MPF, C-MOS, IGF-1, BAX). Healthy immature oocytes of Najdi sheep were cultured in a medium supplemented with 5.0% Sider or Nigella sativa (black seed) honey + 1.0 μg/mL honeybee pollen, and after 24 h of incubation, the effects on the improvement of in vitro oocyte maturation were evaluated. Results demonstrated that the mean oocyte maturation rate was the best in group treated with 5% N. sativa (Group 3) compared with group treated with Sider or N. sativa honey (Group 1A and B, respectively). Mean GSH level was higher in Group 3 oocytes (11.09 ± 0.29 nmol) than in Group 2 oocytes (honey alone; 10.93 ± 0.57; P ≤ 0.05). Mean GSH levels were significantly decreased in Group 1. Expression analysis of candidate genes showed significant upregulation of GDF-9, cyclin B, C-MOS and IGF 1 genes in Group 3 and downregulation of BAX compared with control Group 1. In conclusion, addition of 1.0 μg/mL honeybee pollen along with one of two types of bee honey (Sider and N. sativa) at 5% concentration to the in vitro maturation medium of Najdi sheep oocytes has a beneficial effect in improving the maturation rate and gene expression and increasing the glutathione concentration in matured oocytes. © 2020 Friends Science Publishers

Sequencing and Polymorphism detection in growth hormone gene in Najdi Sheep and their association with milk production

This study was aimed to evaluate the relationship between growth hormone (GH) gene polymorphism and milk production in Najdi sheep. Two hundred Najdi ewes were used to determine the daily milk yield (DMY). The complete CDS of the Najdi sheep GH gene is1950 in length, GenBank acc. no. KU310891.1. Najdi sheep GH protein consists of 217 amino acids GenBank ALT22407.1 with conversion amino acid arginine number 121 to amino acid lysine (R121K). A novel five SNPs were detected in Najdi sheep GH gene (G871A, A1259C, G1383A, A1486G and A1509G). A significant association between the detected SNPs genotypes and daily milk yield was found in this study. The regression analysis indicated the positive effect of genotype and SNPs on DMY. Individuals carrying homozygote mutant alleles had the highest DMY. Consequently, these SNP may be useful indicators in the selection of ewes for milk production.