Journal of Livestock Science and Technology
Volume:8 Issue: 2, Dec 2020

The study aimed to evaluate the chemical composition and the effects of Nepeta glomerulosa Boiss. (Lamiaceae) essential oil (NGEO) on in vitro gas production and ruminal fermentation. The essential oil (EO), obtained by steam distillation from Nepeta glomerulosa Boiss. (0, 150, 300, and 450 mg/L), was investigated in an in vitro culture medium using sheep rumen fluid and artificial saliva. A fattening diet was used as the substrate in the culture medium and gas production was measured. The profile of NGEO was determined by GC-mass analysis. The 1, 8-cineole (23.2%), α-pinene (15.3%), limonene (9.1%), and β-pinene (3.5%) were the major components in NGEO. Ammonia nitrogen and total volatile fatty acids (TVFA) concentrations did not change when NGEO was added to the culture medium, whereas TVFA tended to increase at the higher concentration of NGEO (p <0.1). The pH value of the culture medium linearly and quadratically decreased with increasing NGEO (p <0.05). The potential of gas production (bgas; linear, and quadratic, p <0.05) increased with increasing NGEO, however, the constant rate decreased linearly and quadratically (p <0.05). Dry matter (DMD) and organic matter degradability (OMD) were increased (linear and quadratic) with increasing NGEO in the culture medium. The partitioning factor (PF), microbial mass yield (MMY), and efficiency of microbial mass synthesis (EMMS) linearly and quadratically decreased when the concentration of NGEO increased. It seems that NGEO affected the fermentation process in vitro partly via improving TVFA production or by increasing DMD and OMD. Further in vitro and in vivo studies are needed to confirm that NGEO in the diet has no adverse effects on the health and production in ruminants.

Nowadays, assisted reproduction has become an essential part of the management of horse reproduction in different parts of the world. In vitro production of equine embryos requires established techniques including oocyte collection, in vitro oocyte maturation and intracytoplasmic sperm injection. No report is available on in vitro oocyte maturation of horse oocytes in Iran. Ovaries were immediately collected from newly dead mares of different ages, and transported to the laboratory. The visible follicles were opened using a scalpel blade and the granulosa layers of the follicle wall were scraped from the follicle. Then, the ovaries were cut in 5 mm sections to collect more oocytes from follicles within the ovarian stroma. The oocytes were cultured in TCM-199 medium, supplemented with 10% fetal calf serum and hormones, in a CO2 incubator at 38.5 0C for 30 h. In addition, using a home assembly devised ovum pick-up (OPU) system, five attempts were made to collect oocytes from preovulatory follicles in four mares. After 30 h in culture, the denuded oocytes were fixed and stained with aceto-orcein to determine the nuclear maturation of the oocytes. Out of 29 cultured oocytes from dead mares, 15 (51.7%) oocytes reached the metaphase II. Further, of five OPU operations on live mares, one compact COC suitable for culture and one degenerate COC were collected. The results of this report describe the feasibility of ovum pick-up and oocyte collection from either live mares or immediately after death of the animal and further successful in vitro maturation of the equine oocytes.

It seems that; long exposure to equine chorionic gonadotropin (eCG) in ewe synchronization programs would stimulate the growth of ovarian follicles resulting in better reproductive performance. Therefore, the aim of present study was to expose Farahani ewes to longer duration of eCG by using an eCG-alhydrogel mixture as a slow-release eCG. Fifty Farahani ewes (3-4 years, 44 ± 1.3 kg BW, BCS 3.04±0.3 on scale 1 to 5) were treated with controlled internal drug release (CIDR) for 14 days. The experimental groups consisted of: control group receiving no eCG, and four groups of ewes receiving either 400 IU eCG or eCG-alhydrogel preparation (i.m.) at 24 h (-24S, and -24SR groups, respectively), or 48 h (-48S and -48SR groups, respectively) prior to CIDR removal. Blood samples were taken from two days before until one day after CIDR removal. Reproductive performance was recorded at lambing. There was no difference (P>0.05) between groups in terms of the pregnancy rate, lambing rate, fertility, multiple birth and fecundity. However orthogonal contrasts showed that the fecundity and multiple birth were higher (p <0.05) in eCG-alhydrogel ewes. In all groups, estradiol concentration showed an increasing trend with time (p <0.05). Estradiol concentration was significantly higher in the -48SR compared with the -48S group; no difference was observed between 24S and -24SR ewes (P>0.05). The findings indicated that in an estrous synchronization protocol, administration of slow- release eCG preparations might improve the fecundity and multiple births in sheep. Keywords: alhydrogel, estrous synchronization, Farahani ewe, reproductive performance

A multiple marker analysis approach in the framework of the mixed-effects model was developed, allowing all markers of the entire genome to be included simultaneously in the analysis. The approach was extended to multitrait situations. The proposed method is a one-stage process, which simultaneously models the residuals and genetic effects. In addition, it can easily accommodate co-variates, extra sources of variation, fixed or random including polygenic effects and it can easily be generalized to experimental and crossing designs commonly used. The developed approach considered an unstructured co-variance model for the traits residuals and fitted a multiplicative model for the trait by marker effects. The particular multiplicative model considered herein was the factor analytic model. This provided a parsimonious model specification to limit the numberof parameters to be estimated. It was shown through the simulation study that modelling multiple phenotypes in a single linkage analysis simultaneously could markedly increase the power, compared with modelling of each phenotype separately. Correlations among phenotypes can arise from several different causal processes, which may have different implications for the power and performance of the multivariate linkage analysis. Obviously, further studies using the approach suggested herein for multitrait quantitative trait loci (QTL) mapping that specifically consider different situations, should be undertaken. Furthermore, the efficiency of the model to distinguish between a pleiotropic QTL and closely linked QTL affecting different traits is another area that needs more investigation.

This study was carried out to investigate the polymorphisms of bone morphogenetic protein 15 (BMP15) exon 2 in purebred Kermani and crossbred Romanov × Kermani sheep and functional analysis of the underlying mutations. A number of 50 purebred Kermani and 115 F1 Romanov (ram) × Kermani (ewe) crossbred sheep were sampled and a 153 bp fragment from exon 2 of the ovine BMP15 gene was successfully amplified from the genomic DNA of each animal using designed primers. The polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) technique was used to investigate the polymorphism of BMP15 gene (exon 2(. Twenty samples of different SSCP patterns were randomly selected for DNA sequencing and detecting the BMP15 mutations and subsequent functional analyses. The polymorphic fragments amplified by designed primers were sequenced. There were eight SSCP patterns (AA, AB, BB, AC, AD, AE, AF and AG) with frequencies of 0.24, 0.17, 0.24, 0.08, 0.05, 0.10, 0.03 and 0.09, respectively. The frequency of A allele was obviously higher than those of other alleles. The sequencing results revealed two single nucleotide mutations; the first mutation at position 32bp which did not cause any change in the amino acid sequence but the second mutation led to a change in 40th amino acid (a Lysine amino acid replaced by an Asparagine amino acid). The result of this experiment indicates that the genetic diversity level of BMP15 exon 2 gene was high in the Romanov × Kermani crossbreds indicating that BMP15 exon 2 can played a vital function in the development of ovary and follicles, especially in the improvement of fertility trait and could be used as a potential advantageous molecular marker for reproduction traits in this genetic group. Our finding provides exciting new opportunities for understanding the role of the BMP15 on ovarian follicular growth and development in crossbreed ewes in breeding programs.  However, further investigation using a large population of Romanov × Kermani crossbred sheep is required to confirm the link between the identified mutation and the observed increased prolificacy in this population.

Genome-wide association studies (GWAS) is a major procedure for studying the genetics of complex economically important traits in sheep. The objective of this study was to determine the genomic regions affecting some growth traits and wool characteristics in Zandi sheep. This study is GWAS implementing a medium-density single nucleotide polymorphism (SNP) panel to determine the putative chromosome area affecting some growth and wool traits in a fat-tailed sheep breed, simultaneously. We used a selective genomic approach sampling DNA from animals at the extreme ends using the estimated breeding values derived from a total population size of over 5,000 animals. The examined phenotypic data included the birth weight, weaning weight, 6, 9, and 12-months after birth weight, pre- and post-weaning average daily gain, fiber diameter (micron), prickle factor (%), staple length (mm), kemp (%) and medullated fiber. Genome-wide association analyses were performed based on the mixed linear model. Twenty-three regions, in which four were associated with more than one trait, located on 12 chromosomeswere associated with the studied growth and wool traits (p < 5×10−6). These genomic regions overlapping with KCNIP4, PPARGC1A, ASAP1, ANK2, WWOX, SYNE1, FBXO5, AKAP6, FABP3, ANGPTL4, ATP6V1B2, PARK2, and KRTAP11-1 genes, were associated with postnatal growth, regulation of metabolic pathways, skeletal muscle differentiation, and bone growth. Gene ontology term enrichment analysis revealed that genes involved in positive regulation of muscle structure, and muscle tissue development were over-represented in the identified candidate genes.

The main purpose of this study was to assess the presence of the previously reported single nucleotide polymorphisms (SNPs) in the sheep growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) genes and their association with litter size at lambing in Iran-Black sheep breed. Blood samples were taken from 120 Iran-Black ewes. DNA extraction was conducted using a modified salting-out method. DNA fragments with sizes of 462bp and 141bp for the GDF9 and BMP15 genes were amplified using PCR with specific primers, respectively. The PCR-RFLP approach was adopted for detecting the genotypes. The results indicated that the SNP in the exon 2 of BMP15 is a monomorphic locus in Iran-Black sheep.  However, the substitution of G to A nucleotide was determined in the GDF9 locus. Digestion of the 462bp PCR product from exon 1 of theGDF9 using the HhaI restriction enzyme produced fragments of 52, 156, and 254bp. However, DNA fragments containing the A nucleotide yielded only two fragments (52 and 410bp). The heterozygous animals for this mutation in GDF9 locus had fragments of all four sizes (52, 156, 254, and 410bp). The frequency (0.75) of the wild type allele (+) in GDF9 locus was higher than the frequency (0.25) of mutant allele (G). The observed frequencies for the GG, G+ and ++ genotypes were 0.05, 0.40 and 0.55, respectively.  The association results indicated that the mutation of GDF9 gene has a substantial impact on lambing rate and the Iran-Black ewes with the GG and G+ genotypes had higher lambing rate than those with the ++ genotype. Thus, a gene assisted selection program to improve lambing rate in this breed can be designed based on the GDF9 gene mutation.
Key words: BMP15, GDF9, Litter Size, Iran-Black Sheep