Marion Ryan

Beef contains an array of conjugated linoleic acid (CLA) isomers for which positive effects have been reported in animal models of human disease. The objectives were to develop a CLA-enriched beef production system and to assess its quality. Sixty Spring-born heifers were housed in Autumn and offered unwilted grass silage and a barley/soyabean concentrate or wilted grass silage and a concentrate containing sunflower oil and fish oil. In May, both groups were offered either pasture for 22 weeks, restricted pasture and sunflower oil and fish oil for 22 weeks, or pasture for 11 weeks and restricted pasture and sunflower oil and fish oil for the final 11 weeks. The predominant CLA isomer in beef was cis9, trans11 representing on average, 80% total CLA. The modified winter diet followed by supplementation for 22 weeks resulted in beef that had a CLA concentration that was higher, at a comparable intramuscular fatty acid concentration, than previously reported. The lipid and colour stabil...

This study was conducted to examine the effects of varying selenium (Se) inclusion levels, in the form of Se-enriched mushroom powder (SeMP) and selenite, on post-weaning growth performance (Period 1; day 1–21), intestinal health and antioxidant capacity (Period 2; day 21–39). Weaned pigs were blocked according to live weight, sex and litter of origin and randomly assigned to the following experimental groups: basal (basal + selenite (0.3 ppm Se)); ZnO (basal + ZnO + selenite (0.3 ppm Se)); 0.15 SeMP (basal + SeMP (0.15 ppm Se)); 0.3 SeMP (basal + SeMP (0.3 ppm Se)) and 0.6 SeMP/Sel (basal + SeMP (0.3 ppm Se) + selenite (Sel) (0.3 ppm Se)) with eight replicates/experimental group. After 21 days, the ZnO experimental group was removed from the experiment and the remaining pigs continued on their respective diet until day 39 post-weaning (Period 2). In Period 1, 0.15 SeMP supplementation reduced (p < 0.05) average daily gain (ADG), average daily feed intake (ADFI) and day 21 body w...

Outputs from cScan analysis for human transcripts a) up-regulated and b) down-regulated in the outdoor/pasture-fed group. Table S1. Summary of histone modifications identified on human paralogues and regulatory motifs on the upstream region of the bovine sequence of DE genes. Table S2. Human Ensembl IDs related to gene names of DE genes (a) up-regulated and (b) down-regulated in the pasture-fed group. (DOCX 210 kb)

While feed efficiency is influenced by multiple physiological processes, it is not known how efficient and inefficient pigs differ in relation to their basal immune response, and particularly their innate immune response to a microbial challenge. Hence, the objective was to examine the expression of genes encoding innate immune response markers in basal colonic tissue and colonic tissue following an ex vivo lipopolysaccharide (LPS) challenge from pigs divergent in residual feed intake (RFI). Pigs that differed in RFI were selected from two different farms of origin. Colonic tissue was harvested from high RFI (HRFI) and low (LRFI) pigs, and two experimental conditions were explored: the first was basal unchallenged tissue and the second was colonic tissue following an ex vivo LPS challenge. RNA was extracted and tested on a Nanostring panel of 72 genes coding for barrier defense proteins, transmembrane receptors, kinases, transcription regulators, cytokines, and cytokine regulators. ...

The recovery of high quality RNA from postmortem tissue is crucial to gene expression analyses. The acquisition of postmortem tissue has inherent time delays and, hence, understanding the temporal variation in the stability of total RNA is imperative. This experiment aimed: ( 1 ) to qualitatively and quantitatively assess the integrity of total RNA derived from a range of new-born ovine tissues (liver, spleen, thyroid, skeletal muscle, ileum, and perirenal adipose tissue) which were stored at ambient temperature until extraction at 0, 3, 6, and 9 h postmortem; and ( 2 ) to analyze the stability of the reference gene(s) and expression of specific target genes in these tissues. Postmortem sampling time resulted in variable reductions in the relative integrity number (RIN) values across the tissues, ranging from 0.9 to 1.8% in liver, spleen, skeletal muscle, and ileum to 5.7-11.1% in the thyroid and perirenal adipose tissues, respectively (P < 0.05). In conclusion, tissues with smal...

Differences between cattle production systems can influence the nutritional and sensory characteristics of beef, in particular its fatty acid (FA) composition. As beef products derived from pasture-based systems can demand a higher premium from consumers, there is a need to understand the biological characteristics of pasture produced meat and subsequently to develop methods of authentication for these products. Here, we describe an approach to authentication that focuses on differences in the transcriptomic profile of muscle from animals finished in different systems of production of practical relevance to the Irish beef industry. The objectives of this study were to identify a panel of differentially expressed (DE) genes/networks in the muscle of cattle raised outdoors on pasture compared to animals raised indoors on a concentrate based diet and to subsequently identify an optimum panel which can classify the meat based on a production system. A comparison of the muscle transcript...

Genetic variation at intron 1 of the interferon γ gene has recently been associated with variation in faecal egg count in Romney, Merino and Soay breeds of sheep. The Texel breed is more resistant to gastrointestinal nematode infection than the Suffolk breed, based on faecal egg count. Hence, the objective of this experiment was to characterise the polymorphisms of intron

A potential control strategy for nematode infection in sheep is the implementation of a breeding programme to select for genes associated with resistance. The Texel breed is more resistant to gastrointestinal nematode infection than the Suffolk breed, based on faecal egg count, and this difference should enable the identification of some of the genes responsible for resistance. The objective of this study was to determine if variation at the ovine MHC-DRB1 locus was associated with variation in faecal egg count in Suffolk and Texel sheep. Ovar-DRB1 alleles and faecal egg count were determined for Texel (n=105) and Suffolk (n=71) lambs. Eight Ovar-DRB1 alleles, including 1 previously unknown allele, were identified in the Texel breed by sequence-base-typing. Seven Ovar-DRB1 alleles were identified in the Suffolk breed. Two Ovar-DRB1 alleles were common to both breeds, but were among the least frequent in the Suffolk population. In the Suffolk breed 1 Ovar-DRB1 allele was associated w...

The objectives were to determine the effects of (i) time during the first FSH increase of the estrous cycle (time-course study) and (ii) exogenous steroid treatment (steroid feedback study) on the relationship between circulating serum gonadotropins, and the proportions of pituitary cells immunoreactive for gonadotropins and steroid receptors during the estrous cycle in heifers. Pituitaries were collected from heifers (n=40) slaughtered at 13h (n=8), 30h (n=24) and 66h (n=8) after estrous onset, corresponding to before, during and after the first FSH increase of the estrous cycle. Heifers slaughtered during the FSH increase (at 30h) either received no treatment (n=8), or were treated (n=16) with estradiol benzoate and/or progesterone before slaughter. During the time-course study, the proportion of pituitary cells immunoreactive for FSH increased (P<0.05) during the first transient FSH increase reflecting serum concentrations. The proportion of pituitary cells immunoreactive for LH was unaltered, a reflection of serum LH concentrations. The proportion of estrogen receptors (ER)-alpha, but not ER-beta, was decreased (P<0.05) at 30h compared with at either 13 or 66h. During the steroid feedback study, exogenous progesterone with or without estradiol suppressed (P<0.05) the proportions of pituitary cells immunoreactive for gonadotropins, serum FSH concentrations and LH pulse frequency. Steroid treatment did not alter the proportion of pituitary cells positive for estrogen receptors (alpha and beta). While progesterone receptors (PR) were not detected in the anterior pituitary by immunohistochemistry during the early estrous cycle or in response to steroid treatment, quantitative real-time PCR revealed that mRNA for progesterone receptors was expressed at very low levels. The expression of pituitary PR mRNA was decreased (P<0.05) at 30 and 66h compared with 13h, and was suppressed (P<0.05) following steroid treatments. Alterations in pituitary steroid receptors are implicated in the differential regulation of gonadotropin secretion during the first transient FSH rise, but not in response to exogenous steroids. The time-course study and steroid feedback responses support the hypothesis that LH pulse frequency is tightly linked to regulation of GnRH pulse frequency. Serum FSH is regulated by its own synthesis, as reflected by pituitary FSH content and perhaps by alterations in pituitary sensitivity to circulating steroids by changes in steroid receptor content.

The modern discipline of molecular biology is gaining increasing relevance in the field of veterinary medicine. This trend must be reflected in the curriculum if veterinarians are to capitalize on opportunities arising from this field and direct its development toward their own goals as a profession. This review outlines current applications of molecular-based technologies that are relevant to the veterinary profession. In addition, the current techniques and technologies employed within the field of molecular biology are discussed. Difficulties associated with teaching a subject such as molecular biology within a veterinary curriculum can be alleviated by effectively integrating molecular topics throughout the curriculum, pitching the subject at an appropriate depth, and employing varied teaching methods throughout.

This article describes and evaluates two molecular biology practical classes based around the theme of genetic susceptibility to scrapie in sheep. These practical classes allow students to experience a range of molecular biology techniques in the context of a clinically based genetic disease. The two molecular biology practical classes described are evaluated in terms of their perceived usefulness to study by first-year veterinary medicine students. The students' ratings are then assessed in relation to the approaches to studying (i.e., deep, strategic, and surface). These dimensions of learning are measured using the 52-item Approaches to Studying Inventory (ASI). The overall ratings from students in relation to both the practical classes were found to be positive. The scrapie genotyping practical was the highest-ranking laboratory-based practical in the first-year curriculum. Ratings in terms of usefulness to studies for both practical classes were found to be significantly higher for students with higher deep learning scores. The practical classes described here provide a clinically relevant scenario within which molecular biology concepts and methods can be illustrated to veterinary students. The positive correlation with deep learning is more evident for the scrapie genotyping practical than for the DNA extraction practical. This may reflects the complexity of the former, which is greater both technically and conceptually.

Summary In this study we examined the issue of workload in the veterinary curriculum. The findings illustrate a significant relationship between the approaches to study and perception of workload. The Surface learning approach correlated significantly and positively with a perception of workload. Strategic learning correlated positively and significantly with time spent engaging in independent study. Perception of workload remained high

Fasciola hepatica is a common and economically important parasite of sheep and cattle. Although its marked genetic heterogeneity is well recognised, an association between haplotypes and specific phenotypic traits has yet to be identified. Using experimental infections in cattle this study investigated whether a fragment of mitochondrial DNA (coding for cytochrome c oxidase subunit III, transfer RNA histidine and cytochrome b) and 3 nuclear microsatellite loci (Fh15, Fh23 and Fh25) could be used as markers for the parasite's ability to complete its tissue migration and establish in the liver of the final host. While we did not detect any shift in the frequency of the various genotypes in the population of metacercariae used for the infection on the one hand and the flukes collected from the liver on the other, there was an indication that parasites with heterozygous microsatellite alleles may have a selective advantage over homozygote parasites during their migration in the final host.

This study examines associations between SNPs in the promoter region of the fatty acid binding protein 3 (FABP3) gene and fatness traits in pure bred Large White (n=98), Duroc (n=99) and Pietrain (n=98) populations. In the Large White breed, SNP g.-634 C>A was associated a 27% increase in IMF (%) in the heterozygote (CA) and a 38% increase in the homozygote (CC) relative to the (AA) genotype in the M. semimembranosus (SM) muscle (P=0.02). While the associations observed in this breed were suggestive of significance in both the SM and in the M. longissimus thoracis et lumborum (LTL) (P=0.08), these associations no longer attained significance at thresholds adjusted for multiple testing. In conclusion, SNPs in the FABP3 promoter may contribute to IMF without influencing carcass fatness traits in pigs, however further confirmation of these associations in larger independent populations would be essential before their incorporation into breeding programmes.

The PRKAG3 gene encodes the γ3 subunit of adenosine monophosphate activated protein kinase (AMPK), a protein that plays a key role in energy metabolism in skeletal muscle. Non-synonymous single nucleotide polymorphisms (SNPs) in this gene such as I199V are associated with important pork quality traits. The objective of this study was to investigate the relationship between gene expression of the PRKAG3 gene, SNP variation in the PRKAG3 promoter and meat quality phenotypes in pork. PRKAG3 gene expression was found to correlate with a number of traits relating to glycolytic potential (GP) and intramuscular fat (IMF) in three phenotypically diverse F1 crosses comprising of 31 Large White, 23 Duroc and 32 Pietrain sire breeds. The majority of associations were observed in the Large White cross. There was a significant association between genotype at the g.-311A>G locus and PRKAG3 gene expression in the Large White cross. In the same population, ten novel SNPs were identified within a 1.3 kb region spanning the promoter and from this three major haplotypes were inferred. Two tagging SNPs (g.-995A>G and g.-311A>G) characterised the haplotypes within the promoter region being studied. These two SNPs were subsequently genotyped in larger populations consisting of Large White (n = 98), Duroc (n = 99) and Pietrain (n = 98) purebreds. Four major haplotypes including promoter SNP's g.-995A>G and g.-311A>G and I199V were inferred. In the Large White breed, HAP1 was associated with IMF% in the M. longissmus thoracis et lumborum (LTL) and driploss%. HAP2 was associated with IMFL% GP-influenced traits pH at 24 hr in LTL (pHULT), pH at 45 min in LTL (pH(45)LT) and pH at 45 min in the M. semimembranosus muscle (pH(45)SM). HAP3 was associated with driploss%, pHULT pH(45)LT and b* Minolta. In the Duroc breed, associations were observed between HAP1 and driploss% and pHUSM. No associations were observed with the remaining haplotypes (HAP2, HAP3 and HAP4) in the Duroc breed. The Pietrain breed was monomorphic in the promoter region. The I199V locus was associated with several GP-influenced traits across all three breeds and IMF% in the Large White and Pietrain breed. No significant difference in promoter function was observed for the three main promoter haplotypes when tested in vitro. Gene expression levels of the porcine PRKAG3 are associated with meat quality phenotypes relating to glycolytic potential and IMF% in the Large White breed, while SNP variation in the promoter region of the gene is associated with PRKAG3 gene expression and meat quality phenotypes.