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Mansur F.,University of Massachusetts Medical School | Ivshina M.,University of Massachusetts Medical School | Gu W.,University of California at Riverside | Schaevitz L.,Animal Research and Development | And 4 more authors.
RNA | Year: 2016

Gld2, a noncanonical cytoplasmic poly(A) polymerase, interacts with the RNA binding protein CPEB1 to mediate polyadenylationinduced translation in dendrites of cultured hippocampal neurons. Depletion of Gld2 from the hippocampus leads to a deficit in long-term potentiation evoked by theta burst stimulation. At least in mouse liver and human primary fibroblasts, Gld2 also 3′ monoadenylates and thereby stabilizes specific miRNAs, which enhance mRNA translational silencing and eventual destruction. These results suggest that Gld2 would be likely to monoadenylate and stabilize miRNAs in the hippocampus, which would produce measurable changes in animal behavior. We now report that using Gld2 knockout mice, there are detectable alterations in specific miRNA monoadenylation in the hippocampus when compared to wild type, but that these modifications produce no detectable effect on miRNA stability. Moreover, we surprisingly find no overt change in animal behavior when comparing Gld2 knockout to wild-type mice. These data indicate that miRNA monoadenylation-mediated stability is cell type-specific and that monoadenylation has no measurable effect on higher cognitive function. © 2016 Mansur et al.


Heo J.M.,University of Manitoba | Heo J.M.,Murdoch University | Opapeju F.O.,University of Manitoba | Pluske J.R.,Murdoch University | And 3 more authors.
Journal of Animal Physiology and Animal Nutrition | Year: 2013

Summary: For the last several decades, antimicrobial compounds have been used to promote piglet growth at weaning through the prevention of subclinical and clinical disease. There are, however, increasing concerns in relation to the development of antibiotic-resistant bacterial strains and the potential of these and associated resistance genes to impact on human health. As a consequence, European Union (EU) banned the use of antibiotics as growth promoters in swine and livestock production on 1 January 2006. Furthermore, minerals such as zinc (Zn) and copper (Cu) are not feasible alternatives/replacements to antibiotics because their excretion is a possible threat to the environment. Consequently, there is a need to develop feeding programs to serve as a means for controlling problems associated with the weaning transition without using antimicrobial compounds. This review, therefore, is focused on some of nutritional strategies that are known to improve structure and function of gastrointestinal tract and (or) promote post-weaning growth with special emphasis on probiotics, prebiotics, organic acids, trace minerals and dietary protein source and level. © 2012 Blackwell Verlag GmbH.


Heo J.M.,Murdoch University | Kim J.C.,Animal Research and Development | Hansen C.F.,Murdoch University | Hansen C.F.,Copenhagen University | And 5 more authors.
Livestock Science | Year: 2010

The interactive effects of dietary protein level, zinc oxide (ZnO) supplementation and experimental infection with enterotoxigenic E. coli (ETEC) on the incidence of post-weaning diarrhoea (PWD) and indices of protein fermentation were examined. Ninety-six, individually housed 21-day-old pigs were used in a split plot experiment, with the whole plot being challenge or no challenge with ETEC and the dietary treatments used as subplots and arranged in a completely randomised 2×2 factorial design, with the factors being (i) 2 dietary protein levels [251g/kg (high) vs. 192g/kg (low) crude protein] and (ii) addition or no addition of 2500ppm ZnO. Between days 1 and 14 after weaning, ETEC infection increased faecal consistency (FC; looser faeces) but only in pigs fed the high protein diet (P<0.05) or without ZnO (P<0.1). Pigs fed a high protein diet without ZnO showed more loose faeces (higher FC) compared to pigs fed either a high protein diet with ZnO supplementation or pigs fed lower protein diets without and with ZnO supplementation (P<0.05). Feeding either a low protein diet or ZnO decreased (P<0.05) PWD. Feeding a low protein diet decreased (P<0.001) plasma urea nitrogen (PUN) and faecal NH3-N contents. There were no 2- or 3-way interactions (P>0.05) between the independent variables for PWD, PUN and faecal NH3-N. The results indicate that feeding a low protein diet supplemented with amino acids or adding ZnO to either low or high protein diets could be used as dietary strategies to reduce PWD in piglets. © 2010 Elsevier B.V.


Heo J.M.,Murdoch University | Kim J.C.,Animal Research and Development | Hansen C.F.,Murdoch University | Hansen C.F.,Copenhagen University | And 3 more authors.
Animal Feed Science and Technology | Year: 2010

This study evaluated possible nutritional and physiological mechanisms to explain why feeding a diet of decreased protein content reduces PWD. A total of 48 male pigs weaned at 21 d (initial BW 6.9±0.11kg; mean±SEM) was used in a 2×2×2 factorial arrangement of treatments with the respective factors being: (1) PL (HP 239g/kg vs. LP 190g/kg CP); (2) presence or absence of an ETEC challenge; and (3) duration of feeding after weaning until euthanasia (D; 7 d vs. 14 d). No dietary antimicrobial compounds were used, and diet LP contained crystalline AA including isoleucine and valine to achieve an ideal AA pattern. Pigs were offered the experimental diets on an ad libitum basis. Feeding a LP diet decreased total N intake, ileal N flow, PUN and NH3-N contents at the ileum and all sites in the large intestine (P<0.05-0.001), but did not alter (P>0.05) the AID of N and AA at either d 7 or d 14, except for serine which was lower in pigs fed the LP diet (P<0.001). Feeding diet HP increased the incidence of PWD, and ETEC infection increased PWD only in pigs fed the HP diet (PL×ETEC interaction, P<0.05). Pigs fed diet HP had more PWD at d 7 but not at d 14 after weaning (PL×D interaction, P<0.05). Experimental ETEC infection increased (P<0.001) faecal Escherichia coli score compared to non-infected pigs, and decreased AID of some AA at d 7 (ETEC×D interaction, P<0.05-0.001). Feeding diet LP reduced the molar proportion of BCFA in the caecum and proximal colon (P<0.001 and P<0.05, respectively), but total VFA concentrations in this organ were unaffected by PL (P>0.05). Pigs fed diet LP had decreased pH in the jejunum and ileum (P<0.05 and P<0.01, respectively), while ETEC infection increased pH in the caecum and proximal colon at d 7 (ETEC×D interaction, P<0.05). Feeding diet LP did not alter GIT weight, but ETEC infection adversely affected the proportional weight of the GIT at d 7 (ETEC×D interaction, P<0.01). The PL did not alter small intestinal morphology and growth. These results suggest that feeding a LP diet immediately after weaning reduces the flow of N into the large intestine, thereby decreasing protein fermentation without altering apparent AA digestibility at the ileum. © 2010 Elsevier B.V.


Kim J.C.,Animal Research and Development | Heo J.M.,Murdoch University | Nicholls R.R.,Animal Research and Development | Mullan B.P.,Animal Research and Development | Pluske J.R.,Murdoch University
Livestock Science | Year: 2010

Twenty-four individually housed male pigs (6.6±0.24kg) were used in a pilot study to validate two trivalent metal markers, one in the feed and the other dosed orally to piglets, for the estimation of voluntary feed intake. Pigs were randomly assigned to one of three oral dosing treatments using 15mg lanthanum oxide/day as the internal marker: once daily, twice daily, or 3 times daily. Piglets were offered a diet containing 1g/kg of yttrium as the external marker. After a 7-day adaptation period, total faecal collection was made for the next 3days. The first faecal sample voided after 1000h was considered as the 'grab sample', to allow comparison of the technique with total collection. Intake of diets was recorded daily, and compared to feed intake using the ratio of the markers in the faeces. Daily samples were analysed for marker concentrations and a mean of the three-day data was used for regression analysis. Total collection data demonstrated that the accuracy of the estimation using the trivalent metals depended on the frequency of oral marker administration, as the estimation principle relies on the continual flow of a known amount of marker in the gastrointestinal tract (GIT). Nevertheless and using total collection, dosing the oral marker 3 times a day estimated individual feed intake with reasonable accuracy (R2=0.85). In contrast, the 'grab sampling' technique reduced the accuracy of estimation (R2=0.74), indicating that continual flow of the oral marker in the GIT is required for such a method. In conclusion, there is some potential in using trivalent metal markers to quantitatively estimate the feed intake of an individual pig, however the level of accuracy requires improvement. © 2010 Elsevier B.V.

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