<div>Background:&nbsp;Circular RNAs (circRNAs), a novel class of endogenous non-coding RNAs with covalently closed loop structures, play important role in mammalian growth and development by regulating gene expression and participating in various biological processes. The aim of this study was to identify the expression profiles of circRNAs in the ovaries of Hu sheep and local Fat-tailed sheep during the luteal phase to determine the molecular mechanisms underlying the effects of circRNAs on reproduction and follicular development in sheep. 
 
Methods: To identify the differentially expressed circRNAs expressed in luteal phase conditions in Hu sheep and fat-tailed sheep, ovarian samples collected during the luteal phase were analyzed using high-throughput sequencing and subsequent transcriptomic approaches and bioinformatics analysis. 
 
Result:&nbsp;A total of 2,875 differentially expressed circRNAs were identified by high-through sequencing. Gene Ontology terminology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the host genes were mainly involved in the secretion and metabolism of the various pathway. Quantitative real-time PCR was performed to validate the results of expression profiling. These results contributed to an improved understanding of circRNA and the biological mechanisms of ovarian reproduction in sheep.</div>

Identification of Circular RNAs in the Ovaries of Hu Sheep and Local Fat-tailed Sheep during the Luteal Phase

<div>Background: MicroRNAs (miRNAs) are active regulators of numerous biological and physiological processes and play an important role in the regulation of animal ovaries and other reproductive related organs. To understand the molecular mechanisms of miR-10 family, we investigated the molecular characteristics and the relative expression of sheep miR-10a and miR-10b (miR-10a/b) and conducted bioinformatics analysis. 
 
Methods: During the period 2018-2019 total of 20 samples including blood and tissues such as hypothalamus, pituitary and ovary were collected from the Hu sheep raised in the National Meat Sheep Experimental Station of China (Luoyang City, Henan Province, China). Blood was collected from jugular vein by vacuum and anticoagulation blood collection tube and stored in refrigerator at -20&deg;C. The tissues were placed into the cryopreservation tube treated with Diethy pyrocarbonate (DEPC) water and stored in liquid nitrogen. All the samples were processed for isolation and confirmed with biochemical analysis and Polymerase chain reaction (PCR) and Real-time fluorescence quantitative PCR. 
 
Result: The target genes were predicted by three kinds of target gene predicting software. The function of target genes and their involved pathways were obtained by gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The relative expression of miR-10a/b in sheep ovary was extremely significantly higher than that in hypothalamus and pituitary gland (P &lt; 0.01). The relative expression of miR-10b in ovary or pituitary was extremely significantly higher than that of miR-10a (P &lt; 0.01) and the relative expression of miR-10b in hypothalamus was significantly higher than that of miR-10a (P &lt; 0.05). These results serve as a foundation for further study on the Sheep miR-10 family.</div>

<div>Cloning, Characterization and Bioinformatics Analysis of the Sequences of miR-10a and miR-10b in Sheep (Hu sheep)</div>

<div>Background: Heart is the principal organ of circulatory system that pumps blood into the blood vessels and performs many vital functions. Studies on its development before birth of utmost important to safeguard the animal from the occurrence and consequences of various developmental anomalies. The ultrastructural details of ventricular architecture of heart especially in pre-natal sheep has not yet been reported. &nbsp;&nbsp; 
 
Methods: The collected foeti of sheep were divided into three age groups viz. early prenatal (up to 50 days), mid prenatal (51-100 days) and late prenatal (101 to 150 days). The samples from ventricles were processed for scanning electron microscopic study and subsequently, the samples were viewed and the photographs were taken in the facility available at Central Instrumentation Facility (CIF), OUAT, Bhubaneswar. The measurements of various parameters of ventricles were also taken at the ultrastructural level. The recorded data were subjected to routine statistical analysis. &nbsp;&nbsp; 
 
Result: It was observed that the endocardium of the ventricles consisted of a simple squamous epithelium. The endothelial cells were elongated in shape and arranged linearly on the surface of ventricles in 33 days prenatal non-descript sheep. The boundaries among the endothelial cells were indistinct in this age group. There was presence of pores among the endothelial cells on the surface of the ventricles. In late prenatal period, the endothelial cells of the ventricles became elongated in shape. The subendocardial layer consisted of connective tissue fibers and conducting purkinje fibers, which were quite predominant in the late prenatal period, i.e. at the age of 120 days of gestation. The endocardial fibers were distinctly coiled around the endothelial cells of the ventricles in this age group. The myocardium comprised of cylindrical and highly branched cardiac muscle fibers with pores all over the surface of the myocardium of the ventricles. Each muscle bundle in the myocardium consisted of muscle fibers extending parallel to each other longitudinally and that these fibers made collateral connections with each other in some regions. The papillary muscles were ridge like structures projecting into the lumen of the ventricles of heart. The chordae tendinae connected the papillary muscles and the bicuspid and tricuspid valves. The endothelial surface of the chordae tendinae consisted of elongated endothelial cells with pores among them. The pores of various sizes were arranged linearly in patches on the endothelial surface of the chordae tendinae of the ventricles especially in the late prenatal period, i.e. at about 105 days of gestation. &nbsp; &nbsp;</div>

<div>Scanning Electron Microscopic Studies on the Ventricular Architecture of Pre-natal Non-descript Sheep</div>

<div>Background: Heart is the principal organ of circulatory system that pumps blood into the blood vessels and performs many vital functions. Its development before birth must be studied to safeguard the animal from the occurrence and consequences of various developmental anomalies. The detailed morphometry of different external parameters of heart especially in pre-natal sheep has not yet been reported. 
 
Methods: The foeti of sheep were divided into three age groups viz. early prenatal (up to 50 days), mid prenatal (51-100 days) and late prenatal (101 to 150 days) with fifteen animals in each age group. The various external parameters were recorded by using digital weighing machine, graduated measuring cylinder, digital Vernier&rsquo;s calliper, non-stretchable nylon thread and graduated scale. The data recorded was statistically analysed by one way ANOVA with IBM SPSS 25.0 version software.&nbsp; 
 
Result: It was revealed that the average width of heart at its base was 4.82&plusmn;0.22mm, 10.52&plusmn;0.72mm and 21.57&plusmn;1.03mm in early prenatal, mid prenatal and late prenatal stages respectively. The average dorso-ventral length of left ventricle of heart was measured as 4.82&plusmn;0.14mm, 12.07&plusmn;1.16mm and 25.58&plusmn;0.88mm in early prenatal, mid prenatal and late prenatal stages respectively. The average distance between the left longitudinal groove and cranial border of heart at base was measured as 2.93&plusmn;0.11mm, 6.38&plusmn;0.39mm and 9.78&plusmn;0.41mm in early prenatal, mid prenatal and late prenatal stages respectively. Similarly, the average distance between the right longitudinal groove and cranial border of heart at middle was measured as 1.96&plusmn;0.09mm, 5.01&plusmn;0.34mm and 8.31&plusmn;0.50mm in early prenatal, mid prenatal and late prenatal stages respectively. All these parameters recorded showed significant (p &le; 0.01) differences among the ages.</div>

<div>Morphometrical Studies on the Exterior of the Heart of Pre-natal Non-descript Sheep</div>

<div>Background: Heart is the central organ of circulatory system that pumps blood into the blood vessels and performs many vital functions. Its development before birth must be studied to safeguard the animal from the occurrence and consequences of various developmental anomalies. The detailed morphometry of different internal parameters of heart especially in pre-natal sheep has not yet been reported. &nbsp;&nbsp; 
 
Methods: The foeti of sheep were divided into two age groups viz. mid prenatal (51-100 days) and late prenatal (101 to 150 days) with fifteen animals in each age group. The various internal parameters were recorded by using digital weighing machine, graduated measuring cylinder, digital Vernier&rsquo;s calliper, non-stretchable nylon thread and graduated scale. The data recorded was statistically analysed by independent t test with IBM SPSS 25.0 version software.&nbsp; 
 
Result: The average thickness of left ventricular wall of heart was measured as 2.85&plusmn;0.15 mm and 4.28&plusmn;0.07 mm in mid prenatal and late prenatal stages respectively with significant (p&le;0.01) differences between the ages. Similarly, the average diameter of left atrio-ventricular opening of heart was measured as 2.06&plusmn;0.27 mm and 6.08&plusmn;0.36 mm in mid prenatal and late prenatal stages respectively with significant (p&le;0.01) differences between the ages. The average length of septal papillary muscle in right ventricle was measured as 1.12&plusmn;0.10 mm and 3.29&plusmn;0.21 mm in mid prenatal and late prenatal stages respectively with significant (p&le;0.01) differences between the ages. Further, the average length of moderator band in heart was measured as 1.45&plusmn;0.11 mm and 4.34&plusmn;0.23 mm in mid prenatal and late prenatal stages respectively with significant (p&le;0.01) differences between the ages. Similarly, the average length of chordae tendinae in right ventricle of heart was measured as 0.97&plusmn;0.09 mm and 3.50&plusmn;0.34 mm in mid prenatal and late prenatal stages respectively with significant (p&le;0.01) differences between the ages.&nbsp;</div>

<div>Age Wise Internal Morphometrical Studies on the Heart of Pre-natal Non-descript Sheep</div>

<div>Background: Being the vital organ of circulatory system, the development of the heart before birth must be studied to safeguard the animal from the incidence of various developmental anomalies. The ultrastructural details of auricular and atrio-ventricular valvular architecture of heart especially in pre-natal sheep has not yet been reported. &nbsp;&nbsp; 
 
Methods: The collected foeti of sheep were divided into three age groups viz. early prenatal (up to 50 days), mid prenatal (51-100 days) and late prenatal (101 to 150 days). The samples of auricle, bicuspid and tricuspid valves were processed for scanning electron microscopic study (Scanning Electron Microscope, Make: Hitachi and Model: S-3400N) and subsequently, the samples were viewed and the photographs were taken in the facility available at Central Instrumentation Facility (CIF), OUAT, Bhubaneswar. The measurements of various parameters of auricles and valves were also taken at the ultrastructural level by the inbuilt software programming system. The recorded data were subjected to routine statistical analysis. 
 
Result: It was revealed that the endocardium was the inner layer of the auricles of heart. The endothelial surface of the auricles was occupied by the simple squamous epithelium. The endothelial cells were elongated in shape in all the age groups. The subendothelial layer was consisted of connective tissue fibers and conducting fibers. The pectinate muscles covered the inner side of the right and left atria and were interconnected having a network like appearance except in mid prenatal stage, i.e. at 96 days of gestation, where they were arranged linearly. There was presence of pores among the pectinate muscles in both the atria in all the age groups under study. The endothelial surface of the bicuspid or mitral and tricuspid valves was lined by simple squamous endothelium that projected into the lumen of the valve. There was presence of pores among the endothelial cells of the valves. Further, the subendothelial layer was present just below the endothelium and comprised of connective tissue fibers and conducting fibers in both the valves. The width of the fibers in bicuspid valve was not uniform and was further categorized into thick and thin fibers especially in the mid prenatal stage, i.e. at 96 days of gestation. There was presence of clusters of pores among the endothelial cells of the tricuspid valve in the heart especially in the late prenatal stage, i.e. at 120 days of gestation period.</div>

<div>Scanning Electron Microscopic Studies on the Auricular and Atrio-ventricular Valvular Architecture of Pre-natal Non-descript Sheep</div>

Background: Being the vital organ of circulatory system, the development of the heart before birth must be studied to safeguard the animal from the incidence of various developmental anomalies. The histochemical and biochemical details of cardiac architecture especially in pre-natal sheep have not yet been reported.&nbsp; &nbsp; 
 
Methods: The collected foeti of sheep were divided into three age groups viz. early prenatal (up to 50 days), mid prenatal (51-100 days) and late prenatal (101 to 150 days). The samples of heart were processed by routine paraffin technique and cryo technique and after section cutting, the slides were stained by various histochemical staining methods. Further, fresh pieces of the heart samples were also processed for getting tissue extracts for the biochemical analysis.&nbsp; &nbsp; 
 
Result: It was revealed that the PAS activity was observed in the cardiac wall, interatrial septum and interventricular septum in the sheep foeti at all stages of gestation. A variable degree of acid phosphatase activity was noted in the myocardium of heart wall in the sheep foeti at all stages of gestation. The lipid deposition also increased with advancing age in the myocardium of cardiac wall, interatrial septum and interventricular septum in the heart of sheep foeti. The activities of various enzymes like creatine kinase, alkaline phosphatase, serum glutamic-pyruvic transaminase and serum glutamic-oxaloacetic transaminase were high in left ventricle than the right ventricle in the heart of sheep foeti. Certain protein bands of specific molecular weight appeared in the ventricular tissue at specific age of gestation in addition to a group of common proteins which appeared in ventricular tissue of sheep foeti in all age groups under study.

Histochemical and Biochemical Developmental Studies on the Heart in Pre-natal Non-descript Sheep (Ovis aries)

Background: Being the vital organ of circulatory system, the development of the heart before birth must be studied to safeguard the animal from the incidence of various developmental anomalies. The histological and histomorphometrical details of cardiac architecture especially in pre-natal sheep have not yet been reported.&nbsp; &nbsp; 
 
Methods: The foeti of sheep were collected from the local slaughter houses situated at Laxmisagar and Jadupur of Bhubaneswar city. The collected foeti were divided into three age groups viz. early prenatal (up to 50 days) or G-I, mid prenatal (51-100 days) or G-II and late prenatal (101 to 150 days) or G-III. The heart samples of the sheep foeti were processed by routine paraffin technique and after section cutting, the slides were stained by routine Haematoxyline and Eosin stains, Masson&rsquo;s trichrome stain, Verhoeff&rsquo;s stain and Gomori&rsquo;s stain for studying the detailed histological and histomorphometrical parameters.&nbsp; &nbsp; 
 
Result: It was revealed that the cells lining the endocardium and epicardium became elongated from flat shape with advancing age. The intercalated discs appeared continuous from broken lines with advancing age in the myocardium of cardiac wall in sheep foeti. The frequency of blood vessels, connective tissue fibres and connective tissue cells increased with age in the subendothelium, subepicardium, myocardium and epicardium in the sheep foeti. The average thickness of heart chambers, average diameter of the myocardiocytes and their nuclei in atrial and ventricular walls, papillary muscles, pectinate muscles and Purkinje fibre cells revealed an age dependent rise in sheep foeti of G-I to G-III. The frequency distribution of myocardiocytes and fibroblast in myocardium also increased with in sheep foeti of G-I to G-III.

Histological and Histomorphometrical Characterization of the Cardiac Architecture in Pre-natal Non-descript Sheep (Ovis aries)

<div>Background: The study of the homology of loci between different species has allowed the improvement of specific genetic knowledge and the development of several fundamental concepts. Thanks to this method, Wright discovered the correspondence between a gene and an enzyme (Wright, 1917). In ruminants, this correspondence between loci of different species has been demonstrated for a very long time (Lauvergne, 1979). In fact, the objective of this work was, initially, to use microsatellites recommended for sheep (FAO, 2011) for the amplification of bovine DNA to show that these loci are homologous and, then, to study the genetic diversity and population structure of three groups of each of the two species in Tunisia. 
 
Methods: In this study, we used three microsatellite markers (OarFCB304, OarFCB193 and MAF209) to verify whether they can be amplified in both sheep and cattle. For that, we considered 28 samples of sheep species from 3 different populations and 17 samples of cattle belonging to three breeds. The data obtained were also used to study their genetic diversity and population structure.&nbsp; 
 
Result: We have demonstrated the existence of microsatellite regions common to sheep and cattle. Regarding genetic diversity, we observed a heterozygous deficiency in all the studied breeds. Nei&rsquo;s genetic distances were greater between breeds of cattle than between breeds of sheep.</div>

Detection of Homologous Loci in Sheep and Cattle

<div>Background: Hassan sheep is the third most populous breed of the five registered sheep breeds from Karnataka with limited studies on its morphological and carcass characteristics. Hence, the study was undertaken to know the present status of morphological and carcass characteristics of this breed. 
 
Methods: A total of 34 randomly selected flocks were surveyed and the data on various parameters were collected. The morphometrical data was collected on 344 sheep belonging to eight flocks from the breeding tract. The carcass characteristics were documented by slaughtering six male lambs (between nine to twelve months of age). 
 
Result: These sheep had varied coat colours viz. complete white (23.3%), white with light brown patches (58.1%) and white with black patches (18.6%) on head and neck region. It was observed that 40.4 per cent of males and only 1.4 per cent of females were horned. Atrophied ears were noticed in 2.3 per cent of these sheep. The average adult body length (cm), height at wither (cm), chest girth (cm), paunch (cm), ear length (cm), tail length (cm) and average adult body weight (kg) were 66.4&plusmn;0.62, 65.03&plusmn;1.45, 75.2&plusmn;1.02, 76.5&plusmn;1.38, 15.2&plusmn;0.07, 11.5&plusmn;0.07 and 32.7&plusmn;2.03 in males and 63.8&plusmn;0.85, 61.7&plusmn;1.38, 71.8&plusmn;2.32, 74.5&plusmn;2.60, 15.0&plusmn;0.34, 11.3&plusmn;0.08 and 27.8&plusmn;1.21 in females, respectively. The difference in body weight between males and females increased significantly over the age. The pre-slaughter weight (PSW), hot carcass weight (HCW) and dressing percentage recorded were 20.3&plusmn;1.42 Kg, 9.5&plusmn;0.23 kg and 46.80 per cent, respectively.</div>