Project description:Background: Gastrointestinal nematodes are a serious cause of morbidity and mortality in grazing ruminants. The major ovine defence mechanism is acquired immunity, which develops over time in response to infection. Nematode resistance varies both within and between breeds and is moderately heritable (h ~ 0.3). A detailed understanding of the genes and mechanisms involved in protective immunity, and the factors that regulate this response, is required to aid future breeding strategies as well as the development of effective and sustainable nematode control methods. The aim of this study was to compare the abomasal lymph node transcriptome of resistant and susceptible lambs in order to determine biological processes differentially expressed between resistant and susceptible lambs. Results: Scottish Blackface lambs, with divergent phenotypes for resistance, were challenged with 30,000 Teladorsagia circumcincta larvae (L3), and abomasal lymph node recovered at 7 and 14 days post-infection (dpi). High-throughput sequencing of abomasal lymph node cDNA was used to quantitatively sample the transcriptome with an average of 32 million reads per sample. A total of 194 and 144 genes were differentially expressed between resistant and susceptible lambs at 7 and 14 dpi respectively. Differentially expressed networks and biological processes were identified using Ingenuity Pathway Analysis. Resistant animals appear to generate a more rapid immune response as at 7 dpi processes relating to homing of lymphocytes, leukocyte migration and migration of antigen presenting cells were up-regulated. In susceptible animals this response appears to be delayed until approximately 14 dpi. Twenty-four Single Nucleotide Polymorphims (SNP), within 11 differentially expressed genes were tested for association with gastrointestinal nematode resistance in the Scottish Blackface lambs. Four SNPs in two genes (SLC30A2, and ALB) were suggestively associated with faecal egg count. Conclusions: A large number of genes were differentially expressed in the abomasal lymph node of resistant and susceptible lambs responding to gastrointestinal nematode challenge. Resistant Scottish Blackface lambs appear to generate a more rapid immune response to T. circumcincta. In susceptible lambs this response appears to be delayed until approximately 14 days post infection. SNP in two differentially expressed genes were suggestively associated with faecal egg count indicating that differentially expressed genes can be considered as candidate loci for mediating nematode resistance.
Project description:Cistus ladanifer L. is a common shrub endemic to the Mediterranean that is highly concentrated in condensed tannins (CT). CT form complexes with dietary protein that resist microbial degradation in the rumen, which enhances dietary protein utilization in ruminant diets. The objective of this study was to evaluate the utilization of CT in the diet of lambs on the proteomes of muscle, hepatic and adipose tissues. Twenty-four white merino ram lambs were divided in three groups (n=8) fed on different diets: control (16% crude protein - CP), reduced protein (12% CP) and reduced protein treated with CT extract. At the end of the trial, lambs were slaughtered and the longissimus lumborum muscle, hepatic and peri-renal adipose tissues sampled. A two-way approach was used for shotgun proteomic analysis: 2D-DIGE (gel-based) and nanoLC-MS (gel-free). In the muscle, control lambs had lower abundance proteins that partake in the glycolysis pathway. With dietary 12 % CP, lambs had higher abundance of Fe-carrying proteins in the hepatic tissue. Lambs with dietary CT had higher abundance of hepatic flavin reductase. In the adipose tissue, control lambs had lower abundance of fatty-acid synthase. In conclusion, CT inclusion influences specific pathways in lamb tissues.
Project description:Purpose: ATAC-seq was performed on preterm lambs that were ventilated by invasive mechanical ventilation or noninvasive respiratory support utilizing a mask and compared to gestation-age-matched preterm lambs that were not ventilated and naturally delivered term lambs. Methods: Lung chromatin access profiles were generated for: 1) Unventilated preterm lamb, 2) preterm lambs delivered at gd131 and intubated and mechanically ventilated for 3 days, 3) preterm lambs delivered at gd131 and not intubated and resuscitated by placing a face mask over the nose and mouth and controlling O2 delivery via a computer-controlled electronic blower device, 4) unventilated naturally delivered full-term lambs. Results: Using an optimized data analysis workflow, we mapped between 76 and 96 million sequence reads per sample to the sheep genome Conclusions: Our study represents the first detailed analysis of ventilated preterm lung chromatin access, with biologic replicates, generated by ATAC-seq
Project description:In this study, we studied the fibrolytic potential of the rumen microbiota in the rumen of 6 lambs separated from their dams from 12h of age and artificially fed with milk replacer (MR) and starter feed from d8, in absence (3 lambs) or presence (3 lambs) of a combination of the live yeast Saccharomyces cerevisiae CNCM I-1077 and selected yeast metabolites. The fibrolytic potential of the rumen microbiota of the lambs at 56 days of age was analyzed with a DNA microarray (FibroChip) targeting genes coding for 8 glycoside hydrolase (GH) families.
Project description:This study aimed to use a lamb model of preterm birth to investigate the impact of different tidal volume strategies, applied during positive pressure ventilation, on lung injury development. Preterm lambs were ventilated for a total of 15 minutes, followed by a 30 minute ‘rest’ period where lambs were supported via the intact placenta. A group of lambs was also euthanised at birth to act as an unventilated control group. At post-mortem lung tissue was sampled for proteomic analysis. Lung tissue samples were analysed by mass spectrometry-based proteomics using a TMT-11plex labelling approach, followed by nano-liquid chromatography coupled to an Q Exactive HF-X benchtop Orbitrap mass spectrometer in a data-dependent acquisition mode.
Project description:Our group has developed an extra-uterine environment for newborn development (EXTEND) using an ovine model, that aims to mimic the womb to improve short and long-term health outcomes associated with prematurity. This study’s objective was to determine the histologic and transcriptomic consequences of EXTEND on the brain. Histology and RNA-sequencing was conducted on brain tissue from three cohorts of lambs: control pre-term (106-107 days), control late pre-term (127 days), and experimental lambs who were born pre-term and supported on EXTEND until late pre-term age (125-128 days). Bioinformatic analysis determined differential gene expression among the three cohorts and across four different brain tissue sections: basal ganglia, cerebellum, hippocampus, and motor cortex. There were no clinically relevant histological differences between the control late pre-term and EXTEND ovine brain tissues. RNA-sequencing demonstrated that there was greater differential gene expression between the control pre-term lambs and EXTEND lambs than between the control late pre-term lambs and EXTEND lambs. Our study demonstrates that the use of EXTEND to support pre-term lambs until they reach late pre-term gestational age results in brain tissue gene expression that more closely resembles that of the lambs who reached late pre-term gestation within their maternal sheep’s womb than that of the lambs who were born prematurely.
Project description:The common practise of artificially rearing some lambs from prolific meat breeds of sheep constitutes a welfare issue due to increased mortality rates and negative health issues. In this multidisciplinary study, we investigated the possible short and mid-term advantages of artificially feeding fresh ewe’s milk instead of commercial milk replacer on lambs’ growth, health and welfare. Romane lambs were either separated from their mothers on D3 and fed with Lacaune ewes’ milk (LAC, n=13) or milk replacer (REP, N=15), or they were reared by their mothers (MOT, n=15). On D45, they were weaned, gathered in single sex groups until the end of the study on D150. Lamb performance and biomarkers of overall health were assessed by measuring: growth, dirtiness of the perianal area, enteric pathogens in the faeces, total antioxidant status and redox status assessed by plasma reduced (GSH)/oxidized (GSSG) glutathione ratio, and immune response after vaccination against chlamydiosis. As an exploratory approach, blood cell transcriptomic profiles were also investigated. Last, Qualitative Behaviour Assessment was performed as an integrated welfare criteria. LAC and REP never differed in their average daily gain but grew less than MOT lambs in the early suckling period and just after weaning. No effect was detected afterwards. On D30, LAC and REP lambs had lower total antioxidant and higher redox status than MOT lambs but did not differ among themselves. LAC and MOT had a cleaner perianal area than REP lambs on D21, while faecal pathogen infection did not vary between the treatment groups. After vaccination, LAC also had a stronger immune response on D90 compared to REP lambs. Transcriptome analysis performed on D150 showed differential gene expression, mainly in relation to inflammatory, immune and cell cycle response, between male lambs of the LAC group and those of the MOT and REP groups. Based on Qualitative Behaviour Assessment, LAC lambs never differed from MOT lambs in their general activity and varied from REP only on D21; REP lambs were always more agitated than MOT lambs. In conclusion, artificial milk feeding impaired early growth rate, health, and emotional state mainly during the milk feeding period and at weaning. Feeding artificially reared lambs with fresh ewe's milk partly mitigated some of the negative effects induced by milk replacer but without achieving the full benefit of being reared by the mother.
Project description:Samples of perirenal fat tissue from 8 Assaf breed suckling lambs. These animals were selected from a larger group of 17 Assaf suckling lambs for which carcass traits were measured. The 8 selected lambs were those showing the highest and the lowest values, from the larger group, for the percentage of perirenal and cavitary fat relative to the half carcass weight. Hence, considering the values for this trait, we defined the High-PF group (n = 4; average: 3.23 ± 0,.47) and the Low-PF group (n = 4; 1.65 ± 0,.16), respectively.