Ovarian response to P4-PGF-FSH Treatment in Suffolk sheep and P4-PGF-PMSG Synchronization in Cross-bred Ewes, for IVD and ET Protocol

BackgroundThe success of an embryo transfer protocol in sheep depends on many factors, but the choice of drugs for the desired superovulation as well as the conception rate are most essential. Reproductive activity in sheep is characterized by a seasonality influenced by several factors such as photoperiod, latitude, temperature, nutrition and breed. Reproductive seasonality and nutritional condition are the main factors that influence embryo production in sheep. In sheep, some anatomical peculiarities limit the application of traditional reproductive biotechnologies used in cattle. MethodsIn vivo embryo production is often referred to as “multiple ovulation and embryo transfer” and involves ovarian superstimulation of the donor female, insemination or mating, uterine flushing for embryo recovery, and either cryopreservation or transfer of collected embryos to recipients. A total number of 60 sheep and 3 rams were included in this study, divided into 2 groups (receptors/donors). Donor Suffolk sheep were treated for superovulation using the P4‐PGF‐FSH protocol while the cross-bred recipients’ group was synchronized with P4-PGF-PMSG. ResultsOn the first day after superovulation, all ovaries had more than 5 dominant follicles, while corpora lutea were later observed in 83.3% sheep. The recovery rate was 83.3% while 72,9% embryos were transferable. Embryos were transferred directly into recipients. Fertility after 30 days was 68.57%, lambing rate was 91.6%, and CR 62.85%. This study showed that veterinary drugs (P4, FSH, LH, PMSG, PGF) used for superovulation were capable to induce estrus and synchronize ovulation in sheep, are topical and in increasing use worldwide. ConclusionsThe aim of this study was to conclude on the effectiveness of a wider on farm in vivo embryo transfer development program in Suffolk sheep, using several veterinary hormones. The application of a multiple ovulation embryo transfer (MOET) protocol has a positive effect in the production of in vivo derived embryos in Suffolk sheep and can guarantee the success of embryo transfer activity to ewes with lower genetic merit. Our research aimed at representing a model for sheep farms for a rapid improvement of productive traits.

The Influence of Thermal Stress on Serum Biochemical Profile in Sheep

Background: Climatic factors, such as high temperature, high relative humidity, can induce a thermal stress in animals. The phenomenon of mammalian sensitivity to thermal stress, especially in small ruminants, is widely reported in the literature. The present study aimed to analyze temperature and humidity effects on serum metabolic profile and cortisol concentration in sheep. Methods: The experiment was conducted on 40 adult, non-lactating and non-pregnant Suffolk sheep from December 2018 to December 2019. The subgroups were formed by age (two groups): twenty sheep were about 1.5 years old (Group 1) and other twenty - about 3 years old (Group 2). Based on the value of the temperature-humidity index, the following three subgroups were formed: 1) temperature humidity index ≥20; 2) 20 greater than temperature-humidity index greater than 10 and 3) temperature-humidity index less than 10. Blood cortisol concentration and biochemical parameters were measured once per month on the same day, in identical animals. Result: The analysis of biochemical parameters revealed that Group 2 showed significantly higher values for creatinine, phosphorus, zinc and cortisol. All blood indicators, except iron, phosphorus and total bilirubin, were dependent on THI concentration. The highest positive correlation coefficient of cortisol was calculated with urea and total protein. It is concluded that both cortisol and biochemical parameters play a significant role in thermal stress reactions in the Suffolk sheep.

Transmission of the atypical/Nor98 scrapie agent to Suffolk sheep with VRQ/ARQ, ARQ/ARQ, and ARQ/ARR genotypes

Scrapie is a transmissible spongiform encephalopathy that occurs in sheep. Atypical/Nor98 scrapie occurs in sheep that tend to be resistant to classical scrapie and it is thought to occur spontaneously. The purpose of this study was to test the transmission of the Atypical/Nor98 scrapie agent in three genotypes of Suffolk sheep and characterize the distribution of misfolded prion protein (PrPSc). Ten sheep were intracranially inoculated with brain homogenate from a sheep with Atypical/Nor98 scrapie. All sheep with the ARQ/ARQ and ARQ/ARR genotypes developed Atypical/Nor98 scrapie confirmed by immunohistochemistry, and one sheep with the VRQ/ARQ genotype had detectable PrPSc consistent with Atypical/Nor98 scrapie at the experimental endpoint of 8 years. Sheep with mild early accumulations of PrPSc in the cerebellum had concomitant retinal PrPSc. Accordingly, large amounts of retinal PrPSc were identified in clinically affected sheep and sheep with dense accumulations of PrPSc in the cerebellum.

Identifications of immune-responsive genes for adaptative traits by comparative transcriptome analysis of spleen tissue from Kazakh and Suffolk sheep

Aridity and heat are significant environmental stressors that affect sheep adaptation and adaptability, thus influencing immunity, growth, reproduction, production performance, and profitability. The aim of this study was to profile mRNA expression levels in the spleen of indigenous Kazakh sheep breed for comparative analysis with the exotic Suffolk breed. Spleen histomorphology was observed in indigenous Kazakh sheep and exotic Suffolk sheep raised in Xinjiang China. Transcriptome sequencing of spleen tissue from the two breeds were performed via Illumina high-throughput sequencing technology and validated by RT-qPCR. Blood cytokine and IgG levels differed between the two breeds and IgG and IL-1β were significantly higher in Kazakh sheep than in Suffolk sheep (p < 0.05), though spleen tissue morphology was the same. A total of 52.04 Gb clean reads were obtained and the clean reads were assembled into 67,271 unigenes using bioinformatics analysis. Profiling analysis of differential gene expression showed that 1158 differentially expressed genes were found when comparing Suffolk with Kazakh sheep, including 246 up-regulated genes and 912 down-regulated genes. Utilizing gene ontology annotation and pathway analysis, 21 immune- responsive genes were identified as spleen-specific genes associated with adaptive traits and were significantly enriched in hematopoietic cell lineage, natural killer cell-mediated cytotoxicity, complement and coagulation cascades, and in the intestinal immune network for IgA production. Four pathways and up-regulated genes associated with immune responses in indigenous sheep played indispensable and promoting roles in arid and hot environments. Overall, this study provides valuable transcriptome data on the immunological mechanisms related to adaptive traits in indigenous and exotic sheep and offers a foundation for research into adaptive evolution.

Ruminal microbes of adult sheep do not degrade extracellular l-citrulline

This study determined whether extracellular citrulline is degraded by ruminal bacteria of sheep. In the first experiment, whole rumen fluid (3 mL) from six adult Suffolk sheep was incubated at 37 °C with 5 mM l-glutamine (Gln), l-glutamate (Glu), l-arginine (Arg), or l-citrulline (Cit) for 0, 0.5, 1, and 2 h or with 0, 0.5, 2, or 5 mM Gln, Glu, Arg, or Cit for 2 h. An aliquot (50 µL) of the incubation solution was collected at the predetermined time points for amino acids (AA) analyses. Results showed extensive hydrolysis of Gln into Glu and ammonia, of Arg into l-ornithine and l-proline, but little or no degradation of extracellular Cit or Glu by ruminal microbes. In the second experiment, six adult Suffolk sheep were individually fed each of three separate supplements (8 g Gln , Cit, or urea) on three separate days along with regular feed (800 g/animal). Blood (2 mL) was sampled from the jugular vein prior to feeding (time 0) and at 0.5, 1, 2, and 4 h after consuming the supplement. Plasma was analyzed for AA, glucose, ammonia, and urea. The concentrations of Cit in the plasma of sheep consuming this AA increased (P &lt; 0.001) by 117% at 4 h and those of Arg increased by 23% at 4 h, compared with the baseline values. Urea or Gln feeding did not affect (P &gt; 0.05) the concentrations of Cit or Arg in plasma. These results indicate that Cit is not metabolized by ruminal microbes of sheep and is, therefore, absorbed as such by the small intestine and used for the synthesis of Arg by extrahepatic tissues.

Systemic oxidative stress in Suffolk and Santa Ines sheep experimentally infected with Haemonchus contortus

The mechanisms responsible for the imbalance between oxidants and antioxidants in sheep infected with Haemonchus contortus are not well established. This study aimed to prove the hypothesis that oxidative stress occurring during infection by H. contortus varies according to breed, and that the parasite burden correlates with hypoalbuminaemia and anaemia. Thus, after deworming and confirming the absence of infection, two different sheep breeds, Suffolk (n = 15) and Santa Ines (n = 22), were orally inoculated with a single dose of 5,000 L3 of H. contortus. The egg counts per gram of faeces (EPG), packed cell volume (PCV) and concentrations of several plasma markers of oxidative stress (lipid peroxidation, albumin, uric acid, total bilirubin, total antioxidant capacity [TAC], total oxidant concentration [TOC] and the oxidative stress index [OSI]) were quantified before (control group) and during the experimental infection (28, 34 and 42 days post-inoculation). In both breeds, TOC increased at 28 days and TAC increased at 42 days. In Suffolk sheep, there was a positive correlation of EPG with oxidant components (28 days) and a negative correlation of EPG with PCV (42 days). In Santa Ines sheep, there was a positive correlation of EPG with bilirubin (r = 0.492; p = 0.020). H. contortus infection caused oxidative stress, which varied according to the breed. Parasite burden was not associated with hypoalbuminaemia, whereas there was a negative correlation with PCV. This research provides the first evidence that the antioxidant status contributes more to the resilience to H. contortus in Santa Ines sheep compared to Suffolk sheep.