Progress 08/01/05 to 07/31/11
Outputs
OUTPUTS: This project has resulted in three scientific publications and two presentations at national scientific meetings. Data and project methods were presented to beef producers at a regional field day held at the Bob Jones Idlewild Research Station, Clinton, LA; fifty producers were in attendance. One mass media article relating to our research was published in the Louisiana Cattlemen's and Louisiana Farm and Ranch Magazines. PARTICIPANTS: PI's Jason Rowntree and Kenneth Bondioli particiapted in this project. Graduate students Kyle Guidry, Elizabeth Lum and David Skeans participated in this project and used all or part of this work toward their degrees. TARGET AUDIENCES: Beef producers, Louisiana Cooperative Extension employees, students and nutritionists in industry and academia. PROJECT MODIFICATIONS: The original PI Dr. Jason Rowntree left LSU and PI responsibility was taken over by Dr. Kenneth Bondioli.
Impacts
Currently, Louisiana beef producers are faced with many challenges. Specifically, costs of production are at record highs complemented by the concern that calf prices will decline because of high grain prices. Along with these challenges, Bovine Respiratory Disease, a complex effecting the respiratory tract of stressed calves, costs the beef industry one billion dollars annually. Louisiana calves have a reputation of incurring sickness from respiratory disease. We believe one premise for this is because of mineral deficiencies. Selenium is a potent antioxidant and murine research indicate animals deficient for the mineral are more apt to be impaired from influenza virus. We are applying the model to a growing calf and using Para influenza-3, a virus similar to influenza. We concluded that 84 d is the minimum time necessary to induce Se deficiency in the growing calf using a torula yeast based diet. Also, our research indicated that bovine glutathione peroxidase-1 mRNA could also be used as indicator of Se status. The laboratory's long-term goal is to investigate nutritionally induced antioxidative suppression and bovine respiratory disease (BRD) challenge using the calf as a model. In order to achieve this objective, we first must accumulate information in vitro.Our objective is to determine if Se deficiency influences turbinate immortalized cell pathology when challenged with bovine parainfluenza-3. Because of the induced prooxidative environment caused by the Se deficiency, we hypothesize that the PI-3 virus, a typically mild BRD virus, undergoes oxidation mutation and in turn is more virulent. Also, we hypothesize that attenuated PI-3 virus in a modified live vaccine also mutates in the Se deficient host cell. We have evaluated Se-deficient culture media conditions, as well as created a stably-transfected bovine turbinate cell line expressing shRNA against bovine GPx-1 in an attempt to mimic the conditions typically observed in vivo in Se-deficient animals. These cells are available for viral passage and sequencing of viral cDNA for the M, HN, and F genes from virus passaged through these cell lines for comparison to the same genes from both the original virus, as well as from virus isolated from cell lines not expressing anti-GPx-1 shRNAs Regarding the use of siRNA to knock down GPx-1 mRNA, we obtained HuSH-29 shRNA constructs designed for knockdown of GPx-1 expression. The bovine GPx-1 sequence (accession # X13684) was used to design four cassettes. These shRNA constructs were then cloned into the HuSH-29 plasmid allowing for puromycin selection of stably-transfected bT cells following transfection. bT cells have proven to be particularly sensitive to both the transfection reagent as well as the DNA itself, and optimization of the transfection protocol was required. As a result of this project we have developed and verified a low Se condition for the culture of bovine cells and serial viral passage. This system is potentially valuable to investigate the interactions between mineral defeciencies and viral infection. siRNA sequences for the knockdown of GPx-1 expression in bovine cells have been established and verified.
Publications
- G. E. Lum, J. E. Rowntree, K. R. Bondioli, L. L. Southern and C. C. Williams. 2009. The influence of dietary selenium on common indicators of selenium status and liver glutathione peroxidase-1 messenger ribonucleic acid. J. Anim. Sci. 87:1739-1746.
- G. Lum, J. Rowntree, K. Bondioli, M. McCarter, L. Southern, and C. Williams. 2008. The influence of calf Se status on glutathione peroxidase-1 and glutathione peroxidase-3 activities, and liver GPx-1 messenger RNA. J. Anim. Sci. Vol. 86, E-Suppl. 2/J. Dairy Sci. Vol. 91, E-Suppl. 1
- IK. Guidry, J. Rowntree, G. Lum, and D. Skeans. 2008. Influence of breed and mineral trough visitation on copper status of beef heifers. J. Anim. Sci. Vol 86, E-Suppl. 3
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: We have established and verified a system for culturing bovine turbinate cells under very low selenium and serum conditions. This system is essential for these studies and will be beneficial for other studies involving the action of selenium. PARTICIPANTS: PhD graduate student Elizabeth Lum participated in this project. Data from this project will be used for part of her PhD dissertation. TARGET AUDIENCES: TARGET AUDIENCES: Beef producers, Louisiana Cooperative Extension employees, students, and nutritionists in industry and academia. PROJECT MODIFICATIONS: In addition to the use of serum-free culture medium for the purpose of inducing cellular oxidative stress, we have begun working towards the establishment of a bovine turbinate cell line that stably expresses a shRNA against GPx-1 for the purpose of knocking down GPx-1 activity. We hypothesize that the knockdown of GPx-1 will mimic selenium deficiency, resulting in a state of cellular oxidation under which PI3 mutagenesis may then be studied.
Impacts
Currently, Louisiana beef producers are faced with many challenges. Specifically, costs of production are at record highs complemented by the concern that calf prices will decline because of high grain prices. Along with these challenges, Bovine Respiratory Disease, a complex effecting the respiratory tract of stressed calves, costs the beef industry one billion dollars annually. Louisiana calves have a reputation of incurring sickness from respiratory disease. We believe one premise for this is due to mineral deficiencies. We are investigating the interface of animal status and the subsequent impact on animal health, namely bovine respiratory disease. Selenium is a potent antioxidant and murine research indicate animals deficient for the mineral are more apt to be impaired from influenza virus. We are applying the model to a growing calf and using Para influenza-3, a virus similar to influenza. However, the first step in applying this model is to document the time necessary to induce a Se deficiency in a growing calf. Using plasma and liver Se, glutathione peroxidase, and glutathione peroxidase mRNA, we concluded that 84 d is the minimum time necessary to induce Se deficiency in the growing calf using a torula yeast based diet. Also our research indicated that bovine glutathione peroxidase-1 mRNA could also be used as an indicator of Se status. The use of low-serum cell culture medium (5% Fetal calf serum, FCS) has been evaluated for effectiveness in inducing selenium deficiency and oxidative stress in bovine turbinate cells. Fetal calf serum used in the experiments was analyzed for selenium concentration and glutathione peroxidase -1 (GPx-1) activity used as an indicator of in vitro selenium-depletion in the cell line. Unfortunately, based on our preliminary results, 5% inclusion of FCS in cell culture medium provides adequate selenium to support functional GPx-1 activity in bovine turbinate cells when compared to GPx-1 activity of the same cell line when cultured in medium containing either 10% FCS or 5% FCS supplemented with graded levels of selenium. We have sucessfully conditioned these cells to divide in serum free medium. We have also designed four different short hair pin RNA (shRNA) sequences to target knock down of expression of Gpx-1. Turbinate cells growing under serum free conditions are being transfected with plasmid vectors expressing these shRNA's. Providing our hypothesis is confirmed, strides with respect to preconditioning programs, mineral supplementation programs and new vaccine development could arise from our work.
Publications
- No publications reported this period
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Work completeted under this projects was included in two Masters Thesis during this year and in one full publication in a refereed journal. PARTICIPANTS: PI's Dr. Jason Rowntree and Kenneth R. Bondioli. MS students Kyle Guidry and David Skeans. PhD student Elizabeth Lum. TARGET AUDIENCES: Beef producers, Louisina Cooperative Extension employees, student and nutritionists in industry and academia. PROJECT MODIFICATIONS: Dr. Jason Rowntree is no longer a faculty member at LSU. The duties of PI for this project have been assumed by Dr. Kenneth Bondioli. Dr. Bondioli has been named PI for the grant awarded by the Louisiana State University Board of Regents which is funding the research conducted by the PhD student Elizabeth Lum.
Impacts
Currently, Louisiana beef producers are faced with many challenges. Specifically, costs of production are at record highs complemented by the concern that calf prices will decline because of high grain prices. Along with these challenges, Bovine Respiratory Disease, a complex effecting the respiratory tract of stressed calves, costs the beef industry one billion dollars annually. Louisiana calves have a reputation of incurring sickness from respiratory disease. We believe one premise for this is due to mineral deficiencies. We are investigating the interface of animal status and the subsequent impact on animal health, namely bovine respiratory disease. Selenium is a potent antioxidant and murine research indicates animals deficient for the mineral are more apt to be impaired from influenza virus. We are applying the model to a growing calf and using Para influenza-3, a virus similar to influenza. We are also developing the selenium deficiency model in bovine turbinate cell lines for challenge with the PI-3 virus. The use of low-serum cell culture medium has been evaluated for effectiveness in inducing selenium deficiency and oxidative stress in bovine turbinate cells. Fetal calf serum (FCS) used in the experiments was analyzed for selenium concentration and glutathione peroxidase -1 (GPx-1) activity used as an indicator of in vitro selenium-depletion in the cell line. Based on our preliminary results, 5% inclusion of FCS in cell culture medium provides adequate selenium to support functional GPx-1 activity in bovine turbinate cells when compared to GPx-1 activity of the same cell line when cultured in medium containing either 10% FCS or 5% FCS supplemented with graded levels of selenium. We are currently evaluating the use of serum-free media for induction of selenium deficiency in bovine turbinate cells. In addition, we are also currently developing protocols for adapting bovine turbinate cells to culture in serum-free conditions.
Publications
- Lum, G.E., J.E. Rowntree, K.R. Bondioli, L.L. Southern and C.C. Williams. 2009. The influence of dietary selenium on common indicators of selenium status and liver glutathione peroxidase-1 messenger ribonucleic acid. J. Anim. Sci. 87:1739-1746.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The amount of time necessary to incur Se deficiencies in calves has been identified and we are also in the process of challenging Se deficient turbinate cell lines with PI-3 virus. We will be able to begin live animal trials in 2009. Results were published in one abstract and presented at the annual meeting of the American Society of Animal Science. PARTICIPANTS: The following graduate students participated in this research and used all or part of this work toward their degree. M.S: Kyle Guidry, Elizabeth Lum and David Skeans. TARGET AUDIENCES: Beef producers, Louisiana Cooperative Extension employees, students, and nutritionists in industry and academia. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Currently, Louisiana beef producers are faced with many challenges. Specifically, costs of production are at record highs complemented by the concern that calf prices will decline because of high grain prices. Along with these challenges, Bovine Respiratory Disease, a complex effecting the respiratory tract of stressed calves, costs the beef industry one billion dollars annually. Louisiana calves have a reputation of incurring sickness from respiratory disease. We believe one premise for this is due to mineral deficiencies. We are investigating the interface of animal status and the subsequent impact on animal health, namely bovine respiratory disease. Selenium is a potent antioxidant and murine research indicate animals deficient for the mineral are more apt to be impaired from influenza virus. We are applying the model to a growing calf and using Para influenza-3, a virus similar to influenza. However, the first step in applying this model is to document the time necessary to induce a Se deficiency in a growing calf. Using plasma and liver Se, glutathione peroxidase, and glutathione peroxidase mRNA, we concluded that 84 d is the minimum time necessary to induce Se deficiency in the growing calf using a torula yeast based diet. Also our research indicated that bovine glutathione peroxidase-1 mRNA could also be used as indicator of Se status. Providing our hypothesis is confirmed, strides with respect to preconditioning programs, mineral supplementation programs and new vaccine development could arise from our work.
Publications
- The influence of calf Se status on glutathione peroxidase-1 and glutathione peroxidase-3 activities, and liver GPx-1 messenger RNA. G. Lum, J. Rowntree, K. Bondioli, M. McCarter, L. Southern, and C. Williams. 2008. J. Anim. Sci. Vol. 86, E-Suppl. 2/J. Dairy Sci. Vol. 91, E-Suppl. 1
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Data and project methods were presented to beef producers at a regional field day held at the Bob Jones Idlewild Research Station, Clinton, LA; fifty producers were in attendance. One mass article relating to our research was published in the Louisiana Cattlemen's and Louisiana Farm and Ranch Magazines.
PARTICIPANTS: The following graduate students participated in this research and used all or part of this work toward their degree. M.S: Kyle Guidry, Elizabeth Lum and David Skeans.
TARGET AUDIENCES: Beef producers, Louisiana Cooperative Extension employees, students, and nutritionists in industry and academia.
Impacts
Currently Louisiana beef producers are faced with many challenges. Specifically, costs of production are at record highs complemented by the concern that calf prices will decline because of high grain prices. These challenges will negatively impact our state beef industry and therefore our research is prioritized to aid in sustaining Louisiana beef cattle producers. Our research focuses are: 1) Practical supplementation and grazing strategies of growing cattle; 2) Establishing mineral statuses of Louisiana beef cattle and 3) the impact of mineral deficiencies on calf immune response indicators. Because of high grain and fertilizer prices, more emphasis has been placed on forage efficiency. We currently examine winter grazing strategies that will aid in identifying economically efficient means of adding weight to developing heifers. Also, because mineral supplements are rising as with other input costs, we are in the process of identifying mineral statuses of beef
cattle across the state to identify the most economical means of supplementing minerals to cattle. Initial reports from forage samples suggest Phosphorus (0.22%)and Potassium (1.55%) concentrations are inadequate to meet beef cow nutrient requirements according to NRC, 2000 while forage Copper (8.082 ppm), Iron (267.91 ppm), Magnesium (0.22%) and Sodium (0.108%) were considered adequate. Bovine Respiratory Disease costs the beef industry one billion dollars annually. Plus, Louisiana calves have a reputation of incurring sickness from respiratory disease. We believe that one premise for this is due to mineral deficiencies. Thus, we are also studying how mineral status of young calves impacts their ability to cope with bovine respiratory disease. Initial results from our Selenium (Se) deficiency trial show a 50% reduction in the mRNA of Glutathione Peroxidase, a selenium requiring antioxidative enzyme, for Se deficient calves (P < 0.05) compared with calves fed a selenium normal diet.
This is the first time mRNA has been reported in the bovine and will be useful for laboratory purposes when assessing selenium status of cattle.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Currently two trials are in progress with a third planned for spring 2007. Fourteen Holstein steers were assigned to a Se deficient or replete diet beginning September of 2006. Lab results are incomplete at this time. The second trial underway is actually an augmented project relative to the intial experiment written into the CRIS project. Initially, we were planning to determine mineral status of differing ages and breeds of cattle. However, because of the way our farm is setup, this trial was changed to determine the influence of breed (Brahman, Braford, and Angus) on mineral status. This trial, like the first, is just underway and lab results are incomplete. Funding for the third trial, A Mineral Survey of Lousiana Cow-Calf Herds, has just been acquired. This trial will begin in March of 2007.
Impacts
The expected impact of this project is to have a greater understanding of mineral supplementation's influence on beef cattle production traits. The knowledge should aid in increasing net returns of beef producers.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
Presently, this project is just beginning. We are in the process of formulating a selenium deficient diet to begin feeding to young Holstein dairy steers. Also, mineral has been obtained to begin offering to females for the other glutathione peroxidase trial. This spring two trials will be inititated to gain a better understanding of mineral supplementation and its influence on beef cattle production in Louisiana.
Impacts
The expected impact of this project is to acquire a greater understanding of mineral supplementation's influence on beef cattle production traits. This knowledge should aid in increasing net returns of beef cattle producers.
Publications
- No publications reported this period
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