The effect of copper supplementation on performance and carcass characteristics of cattle utilizing growth promoting technologies

Growth promoting technologies such as beta agonists and hormone implants are used extensively throughout the feedlot industry (Samuelson et al., 2016). These technologies are known to improve performance and efficiency of growth and thus are vital to sustained profitability for cattle producers. The ability to further improve the effectiveness of these technologies would improve productivity of cattle and may be accomplished through the strategic supplementation of trace minerals such as Cu. Although industry recommendations for Cu are two times NASEM (2016) recommendations, little research has evaluated trace mineral supplementation in addition to growth promoting technologies. Therefore, the effects of greater concentrations of minerals such as Cu in the diet of cattle utilizing growth promoting technologies has not yet been validated. The research trials described in this thesis were designed to 1) determine the effect of Cu status of finishing beef steers on beta agonist induced growth performance and 2) examine the impacts of industry rates of Cu supplementation on the implant growth response of finishing feedlot steers. Through our first research objective, the supplementation of varying concentrations of Cu to finishing feedlot cattle differentially impacted the beta agonist induced performance response of cattle. Within cattle receiving the beta agonist treatment, performance was greatest at Cu supplementation at NASEM (2016) recommendations. These performance differences were observed in Cu supplemented cattle with adequate liver Cu status suggesting further classification of Cu status for optimal growth is needed. Through our second study performance was impacted by an interaction between implant and Cu in which cattle not supplemented with Cu experienced a 24.7% increase in ADG due to implant while industry recommendations of Cu supplementation resulted in a 15.3% improvement in ADG due to implant. Additionally, liver Cu concentrations tended to increase and liver Mn concentrations decreased 14 days after implantation, while liver Zn and plasma Zn revealed trends for decreases due to implant. Together these studies indicate Cu may impact the physiological response to growth promoting technologies and that implants may alter mineral metabolism. Additionally, these data revealed that supplementation of Cu beyond NASEM (2016) recommendations may not promote optimal performance from cattle utilizing growth promoting technologies. Collectively, the studies presented in this thesis find that concentrations of Cu commonly supplemented within the industry are not merited. This work warrants additional research to better understand the role of Cu in growth induced through technologies such as beta agonists and hormone implants

"I can decide to use the property I have to make money": HIV vulnerability of bar workers and bar patrons in Kumasi, Ghana

This study was implemented by Boston University in collaboration with the Kwame Nkrumah University of Science and Technology with support from the President’s Emergency Plan for AIDS Relief (PEPFAR) through the U.S. Agency for International Development under Project SEARCH Task Order No. GHH‐I‐00‐07‐00023‐00, beginning August 27, 2010. The content and views expressed here are the authors’ and do not necessarily reflect the opinion or policy of USAID or the U.S. Government.This report provides the findings from a qualitative study exploring the social, economic and behavioral vulnerability to HIV of women working in bars and restaurants in Kumasi, Ghana’s second largest city. This research was conducted by a collaborative team comprised of researchers from Boston University’s Center for Global and Health and Development (CGHD) and the Kwame Nkrumah University of Science and Technology (KNUST) School of Medical Sciences. It is one of nine studies under the Operations Research on Key Populations project funded by the United States Agency for International Development (USAID). The study was designed and carried out in collaboration with the Ghana AIDS Commission (GAC). Reducing vulnerability to HIV infection among key populations in Ghana is a major goal for the National AIDS Control Program (NACP) and the GAC. While a number of studies have explored HIV risk behaviours among self-identified female sex workers and their partners in Ghana, little is known about the vulnerability of women working in small bars and restaurants who may be involved in transactional sex. Further, we have little information about how best to reach this population with services that will enable them and their clientele to protect themselves from HIV and reduce other vulnerabilities related to their health and well-being. To address this gap, this study aimed to explore behavioural, social, and economic factors that contribute to HIV vulnerability; types and extent of transactional sex; the relationship between alcohol/drug use, unsafe sex and transactional sex; and the health and social service needs of this population. The study findings are meant to inform the development and implementation of HIV prevention programs for bar workers and bar patrons.Support from the President’s Emergency Plan for AIDS Relief (PEPFAR) through the U.S. Agency for International Development under Project SEARCH Task Order No. GHH‐I‐00‐07‐00023‐00, beginning August 27, 201

Effects of an Alpha-4 Integrin Inhibitor on Restenosis in a New Porcine Model Combining Endothelial Denudation and Stent Placement

Restenosis remains the main complication of balloon angioplasty and/or stent implantation. Preclinical testing of new pharmacologic agents preventing restenosis largely rely on porcine models, where restenosis is assessed after endothelial abrasion of the arterial wall or stent implantation. We combined endothelial cell denudation and implantation of stents to develop a new clinically relevant porcine model of restenosis, and used this model to determine the effects of an α4 integrin inhibitor, ELN 457946, on restenosis. Balloon-angioplasty endothelial cell denudation and subsequent implantation of bare metal stents in the left anterior descending coronary, iliac, and left common carotid arteries was performed in domestic pigs, treated with vehicle or ELN 457946, once weekly via subcutaneous injections, for four weeks. After 1 month, histopathology and morphometric analyses of the arteries showed complete healing and robust, consistent restenotic response in stented arteries. Treatment with ELN 457946 resulted in a reduction in the neointimal response, with decreases in area percent stenosis between 12% in coronary arteries and 30% in peripheral vessels. This is the first description of a successful pig model combining endothelial cell denudation and bare metal stent implantation. This new double injury model may prove particularly useful to assess pharmacological effects of drug candidates on restenosis, in coronary and/or peripheral arteries. Furthermore, the ELN 457946 α4 integrin inhibitor, administered subcutaneously, reduced inflammation and restenosis in stented coronary and peripheral arteries in pigs, therefore representing a promising systemic therapeutic approach in reducing restenosis in patients undergoing angioplasty and/or stent implantation

The effects of strategic zinc supplementation on steroidal implant-induced growth of finishing beef cattle

Extensive use of steroidal implants (NAHMS, 2013; Samuelson et al., 2016) has resulted in increased efficiency of growth and profitability in the beef feedlot industry (Duckett and Pratt, 2014). Steroidal implants increase Zn absorption and retention in lambs (Hufstedler and Greene, 1995) and lessen plasma Zn concentrations compared to non-implanted beef steers (Messersmith, 2018). These data indicate steroidal implants affect Zn metabolism in ruminants, potentially to support the rapid growth occurring in implanted animals. Therefore, strategic supplementation of Zn may optimize growth performance of cattle administered steroidal implants. The research studies discussed in this dissertation were designed to 1) determine the effects of increasing dietary Zn supplementation on the growth performance, carcass characteristics, and expression of genes related to steroidal implant function and Zn metabolism of non-implanted and implanted beef steers, 2) examine how increasing supplemental Zn concentrations influence performance, carcass characteristics, and markers of energy and protein metabolism in beef steers, 3) assess the effects of supplemental Zn on performance, carcass characteristics, and liver trace mineral concentrations of beef heifers administered an extended-release implant or a two-implant strategy, and 4) evaluate the effects of Zn source on the performance, carcass characteristics, and plasma and tissue trace mineral concentrations within non-implanted and implanted beef steers. Through our first research objective, increasing supplemental Zn, as ZnSO4, up to 5 times the NASEM (2016) recommendation linearly increased steer performance and gene expression of steroidal implant signaling proteins in the muscle during peak hormonal payout of a high potency implant but did not influence these parameters in non-implanted steers. During this period implanted steers had 6% lesser plasma Zn concentrations than non-implanted steers, suggesting steroidal implant-induced growth influences Zn metabolism to accommodate high growth rates. Within our second research objective, increasing Zn supplementation, as ZnSO4, up to 6 times the NASEM (2016) recommendation linearly increased growth during peak hormonal payout of the steroidal implant, but had minimal effects on beta agonist period ADG. Similarly, liver Mn concentrations were correlated with liver arginase activity and ADG directly following implant administration, but not during beta agonist supplementation. These data indicate Zn’s effects on growth, in combination with steroidal implants, influence protein degradation. Through our third research objective, beef heifers supplemented consultant-recommended concentrations of Zn (100 mg Zn/kg dry matter from ZnSO4; Samuelson et al., 2016) were 7 kg heavier than heifers supplemented NASEM (2016; 30 mg Zn/kg dry matter from ZnSO4) recommendations of Zn during peak hormonal payout of the extended-release implant and two-implant strategies. Although no differences in final performance were noted between implant strategies, interim period ADG of heifers corresponded to peak hormonal payout of each implant. These data suggest greater supplementation of Zn is beneficial to the growth of heifers administered either an extended-release implant or two-implant strategy and that these implant strategies are equally effective. Finally, our fourth research objective revealed implanted steers were 45 kg heavier than non-implanted steers at the end of the trial. However, an interaction between implant and Zn source (100% ZnSO4 or 70% ZnSO4 + 30% basic ZnCl or Zn glycinate) was observed in final body weight (BW) where steers supplemented 100% ZnSO4 tended to be heavier than those supplemented a basic ZnCl blend, but not heavier than steers receiving the Zn glycinate blend. No differences in final BW due to Zn source were observed within non-implanted steers. These data suggest steroidal implants influence Zn metabolism resulting in BW differences between Zn sources within implanted steers, but not non-implanted steers. Together, these studies increased our understanding of the Zn requirements of implanted vs. non-implanted cattle. These data suggest feeding greater than NASEM (2016) recommendations for Zn is beneficial to implant-induced growth, likely due to Zn’s roles in protein synthesis (Oberleas and Prasad, 1969; Duncan and Dreosti, 1976) and the observed effects on the gene expression of implant signaling machinery. However, future work is warranted to determine strategic Zn supplementation to optimize implant-induced growth in beef feedlot cattle

The effects of strategic zinc supplementation on steroidal implant-induced growth of finishing beef cattle

Extensive use of steroidal implants (NAHMS, 2013; Samuelson et al., 2016) has resulted in increased efficiency of growth and profitability in the beef feedlot industry (Duckett and Pratt, 2014). Steroidal implants increase Zn absorption and retention in lambs (Hufstedler and Greene, 1995) and lessen plasma Zn concentrations compared to non-implanted beef steers (Messersmith, 2018). These data indicate steroidal implants affect Zn metabolism in ruminants, potentially to support the rapid growth occurring in implanted animals. Therefore, strategic supplementation of Zn may optimize growth performance of cattle administered steroidal implants. The research studies discussed in this dissertation were designed to 1) determine the effects of increasing dietary Zn supplementation on the growth performance, carcass characteristics, and expression of genes related to steroidal implant function and Zn metabolism of non-implanted and implanted beef steers, 2) examine how increasing supplemental Zn concentrations influence performance, carcass characteristics, and markers of energy and protein metabolism in beef steers, 3) assess the effects of supplemental Zn on performance, carcass characteristics, and liver trace mineral concentrations of beef heifers administered an extended-release implant or a two-implant strategy, and 4) evaluate the effects of Zn source on the performance, carcass characteristics, and plasma and tissue trace mineral concentrations within non-implanted and implanted beef steers. Through our first research objective, increasing supplemental Zn, as ZnSO4, up to 5 times the NASEM (2016) recommendation linearly increased steer performance and gene expression of steroidal implant signaling proteins in the muscle during peak hormonal payout of a high potency implant but did not influence these parameters in non-implanted steers. During this period implanted steers had 6% lesser plasma Zn concentrations than non-implanted steers, suggesting steroidal implant-induced growth influences Zn metabolism to accommodate high growth rates. Within our second research objective, increasing Zn supplementation, as ZnSO4, up to 6 times the NASEM (2016) recommendation linearly increased growth during peak hormonal payout of the steroidal implant, but had minimal effects on beta agonist period ADG. Similarly, liver Mn concentrations were correlated with liver arginase activity and ADG directly following implant administration, but not during beta agonist supplementation. These data indicate Zn’s effects on growth, in combination with steroidal implants, influence protein degradation. Through our third research objective, beef heifers supplemented consultant-recommended concentrations of Zn (100 mg Zn/kg dry matter from ZnSO4; Samuelson et al., 2016) were 7 kg heavier than heifers supplemented NASEM (2016; 30 mg Zn/kg dry matter from ZnSO4) recommendations of Zn during peak hormonal payout of the extended-release implant and two-implant strategies. Although no differences in final performance were noted between implant strategies, interim period ADG of heifers corresponded to peak hormonal payout of each implant. These data suggest greater supplementation of Zn is beneficial to the growth of heifers administered either an extended-release implant or two-implant strategy and that these implant strategies are equally effective. Finally, our fourth research objective revealed implanted steers were 45 kg heavier than non-implanted steers at the end of the trial. However, an interaction between implant and Zn source (100% ZnSO4 or 70% ZnSO4 + 30% basic ZnCl or Zn glycinate) was observed in final body weight (BW) where steers supplemented 100% ZnSO4 tended to be heavier than those supplemented a basic ZnCl blend, but not heavier than steers receiving the Zn glycinate blend. No differences in final BW due to Zn source were observed within non-implanted steers. These data suggest steroidal implants influence Zn metabolism resulting in BW differences between Zn sources within implanted steers, but not non-implanted steers. Together, these studies increased our understanding of the Zn requirements of implanted vs. non-implanted cattle. These data suggest feeding greater than NASEM (2016) recommendations for Zn is beneficial to implant-induced growth, likely due to Zn’s roles in protein synthesis (Oberleas and Prasad, 1969; Duncan and Dreosti, 1976) and the observed effects on the gene expression of implant signaling machinery. However, future work is warranted to determine strategic Zn supplementation to optimize implant-induced growth in beef feedlot cattle

The effect of copper supplementation on performance and carcass characteristics of cattle utilizing growth promoting technologies

Growth promoting technologies such as beta agonists and hormone implants are used extensively throughout the feedlot industry (Samuelson et al., 2016). These technologies are known to improve performance and efficiency of growth and thus are vital to sustained profitability for cattle producers. The ability to further improve the effectiveness of these technologies would improve productivity of cattle and may be accomplished through the strategic supplementation of trace minerals such as Cu. Although industry recommendations for Cu are two times NASEM (2016) recommendations, little research has evaluated trace mineral supplementation in addition to growth promoting technologies. Therefore, the effects of greater concentrations of minerals such as Cu in the diet of cattle utilizing growth promoting technologies has not yet been validated. The research trials described in this thesis were designed to 1) determine the effect of Cu status of finishing beef steers on beta agonist induced growth performance and 2) examine the impacts of industry rates of Cu supplementation on the implant growth response of finishing feedlot steers. Through our first research objective, the supplementation of varying concentrations of Cu to finishing feedlot cattle differentially impacted the beta agonist induced performance response of cattle. Within cattle receiving the beta agonist treatment, performance was greatest at Cu supplementation at NASEM (2016) recommendations. These performance differences were observed in Cu supplemented cattle with adequate liver Cu status suggesting further classification of Cu status for optimal growth is needed. Through our second study performance was impacted by an interaction between implant and Cu in which cattle not supplemented with Cu experienced a 24.7% increase in ADG due to implant while industry recommendations of Cu supplementation resulted in a 15.3% improvement in ADG due to implant. Additionally, liver Cu concentrations tended to increase and liver Mn concentrations decreased 14 days after implantation, while liver Zn and plasma Zn revealed trends for decreases due to implant. Together these studies indicate Cu may impact the physiological response to growth promoting technologies and that implants may alter mineral metabolism. Additionally, these data revealed that supplementation of Cu beyond NASEM (2016) recommendations may not promote optimal performance from cattle utilizing growth promoting technologies. Collectively, the studies presented in this thesis find that concentrations of Cu commonly supplemented within the industry are not merited. This work warrants additional research to better understand the role of Cu in growth induced through technologies such as beta agonists and hormone implants.</p

The effects of strategic zinc supplementation on steroidal implant-induced growth of finishing beef cattle

Extensive use of steroidal implants (NAHMS, 2013; Samuelson et al., 2016) has resulted in increased efficiency of growth and profitability in the beef feedlot industry (Duckett and Pratt, 2014). Steroidal implants increase Zn absorption and retention in lambs (Hufstedler and Greene, 1995) and lessen plasma Zn concentrations compared to non-implanted beef steers (Messersmith, 2018). These data indicate steroidal implants affect Zn metabolism in ruminants, potentially to support the rapid growth occurring in implanted animals. Therefore, strategic supplementation of Zn may optimize growth performance of cattle administered steroidal implants. The research studies discussed in this dissertation were designed to 1) determine the effects of increasing dietary Zn supplementation on the growth performance, carcass characteristics, and expression of genes related to steroidal implant function and Zn metabolism of non-implanted and implanted beef steers, 2) examine how increasing supplemental Zn concentrations influence performance, carcass characteristics, and markers of energy and protein metabolism in beef steers, 3) assess the effects of supplemental Zn on performance, carcass characteristics, and liver trace mineral concentrations of beef heifers administered an extended-release implant or a two-implant strategy, and 4) evaluate the effects of Zn source on the performance, carcass characteristics, and plasma and tissue trace mineral concentrations within non-implanted and implanted beef steers. Through our first research objective, increasing supplemental Zn, as ZnSO4, up to 5 times the NASEM (2016) recommendation linearly increased steer performance and gene expression of steroidal implant signaling proteins in the muscle during peak hormonal payout of a high potency implant but did not influence these parameters in non-implanted steers. During this period implanted steers had 6% lesser plasma Zn concentrations than non-implanted steers, suggesting steroidal implant-induced growth influences Zn metabolism to accommodate high growth rates. Within our second research objective, increasing Zn supplementation, as ZnSO4, up to 6 times the NASEM (2016) recommendation linearly increased growth during peak hormonal payout of the steroidal implant, but had minimal effects on beta agonist period ADG. Similarly, liver Mn concentrations were correlated with liver arginase activity and ADG directly following implant administration, but not during beta agonist supplementation. These data indicate Zn’s effects on growth, in combination with steroidal implants, influence protein degradation. Through our third research objective, beef heifers supplemented consultant-recommended concentrations of Zn (100 mg Zn/kg dry matter from ZnSO4; Samuelson et al., 2016) were 7 kg heavier than heifers supplemented NASEM (2016; 30 mg Zn/kg dry matter from ZnSO4) recommendations of Zn during peak hormonal payout of the extended-release implant and two-implant strategies. Although no differences in final performance were noted between implant strategies, interim period ADG of heifers corresponded to peak hormonal payout of each implant. These data suggest greater supplementation of Zn is beneficial to the growth of heifers administered either an extended-release implant or two-implant strategy and that these implant strategies are equally effective. Finally, our fourth research objective revealed implanted steers were 45 kg heavier than non-implanted steers at the end of the trial. However, an interaction between implant and Zn source (100% ZnSO4 or 70% ZnSO4 + 30% basic ZnCl or Zn glycinate) was observed in final body weight (BW) where steers supplemented 100% ZnSO4 tended to be heavier than those supplemented a basic ZnCl blend, but not heavier than steers receiving the Zn glycinate blend. No differences in final BW due to Zn source were observed within non-implanted steers. These data suggest steroidal implants influence Zn metabolism resulting in BW differences between Zn sources within implanted steers, but not non-implanted steers. Together, these studies increased our understanding of the Zn requirements of implanted vs. non-implanted cattle. These data suggest feeding greater than NASEM (2016) recommendations for Zn is beneficial to implant-induced growth, likely due to Zn’s roles in protein synthesis (Oberleas and Prasad, 1969; Duncan and Dreosti, 1976) and the observed effects on the gene expression of implant signaling machinery. However, future work is warranted to determine strategic Zn supplementation to optimize implant-induced growth in beef feedlot cattle

The type-A horizontal cell: GABAergic characteristics and role in development of the outer plexiform layer

Morphological analysis of neonatal rabbit retina suggests that the type-A horizontal cell acts as the pioneer cell for development of the OPL. It is the first mature element of the OPL, and it forms the infrastructure upon which the OPL accrues. The role of type-A horizontal cells in influencing postnatal development of the OPL was examined. GABAergic characteristics of the type-A horizontal cell were defined. The type-A horizontal cell was found to possess two more GABAergic characteristics in addition to those previously demonstrated, during a short period in early postnatal development: endogenous stores of GABA and the GABA precursor, glutamate. Lesioning the type-A horizontal cell resulted in their permanent loss in addition to the disappearance of cone terminals and a dramatic increase in rod terminals within the OPL. Thus the type-A cells are not a necessary prerequisite for positioning the OPL in postnatal development, but may be necessary for establishment of the normal photoreceptor mosaic. Since type-A horizontal cells possess a number of GABAergic qualities during the period of cone photoreceptor cell differentiation, and there are reports of GABA\u27s trophic action in other developing neuronal systems; the role that GABAergic type-A horizontal cells play in directing photoreceptor differentiation was examined. Disrupting effects of GABA-A receptor antagonists indicate that type-A horizontal cells act as postsynaptic targets for the growing cone terminals of photoreceptor cells. These trophic or synaptic interactions may involve GABA-A receptors activated by GABA released from horizontal cells. These findings are consistent with the hypothesis that type-A horizontal cells act as pioneering cells in directing the postnatal development of the OPL. These studies offer an in depth analysis of the structural and chemical relationship between type-A horizontal cells and other elements of the OPL from which the roles of type-A horizontal cells and the GABA system in development can be defined. They contribute to our knowledge of both structural and GABAergic mechanisms involved in central nervous system development

The Crossroads between Zinc and Steroidal Implant-Induced Growth of Beef Cattle

Growth-promoting technologies such as steroidal implants have been utilized in the beef industry for over 60 years and remain an indispensable tool for improving economic returns through consistently improved average daily gain via increased skeletal muscle hypertrophy. Zinc has been implicated in skeletal muscle growth through protein synthesis, satellite cell function, and many other growth processes. Therefore, the objective of this review was to present the available literature linking Zn to steroidal implant-induced protein synthesis and other metabolic processes. Herein, steroidal implants and their mode of action, the biological importance of Zn, and several connections between steroidal implants and Zn related to growth processes are discussed. These include the influence of Zn on hormone receptor signaling, circulating insulin-like growth factor-1 concentrations, glucose metabolism, protein synthesis via mTOR, and satellite cell proliferation and differentiation. Supplemental Zn has also been implicated in improved growth rates of cattle utilizing growth-promoting technologies, and steroidal implants appear to alter liver and circulating Zn concentrations. Therefore, this review provides evidence of the role of Zn in steroidal implant-induced growth yet reveals gaps in the current knowledge base related to optimizing Zn supplementation strategies to best capture growth performance improvements offered through steroidal implants

Initial Liver Copper Status in Finishing Beef Steers Fed Three Dietary Concentrations of Copper Affects Beta Agonist Performance, Carcass Characteristics, Lipolysis Response, and Muscle Inflammation Markers

Ninety-three Angus-crossbred steers (470 ± 35 kg) were assigned to a 3 × 2 factorial to determine the effects of Cu status and beta agonist (BA) on performance, carcass characteristics, lipolytic rate, and muscle inflammation. Factors included Cu supplementation (mg Cu/kg dry matter (DM)) at: 0 (LO), 10 (MED), or 20 (HI) from Cu amino acid complex (Availa Cu; Zinpro) with no BA (NoRAC) or 300 mg·steer−1·day−1 of ractopamine hydrochloride (RAC; Optaflexx; Elanco) for final 28 days of 88-day trial. Linear and quadratic effects of Cu status within BA treatment were tested. Pre-BA gain was not affected by Cu supplementation (p ≥ 0.57), although day 53 liver Cu quadratically increased (p = 0.01). Average daily gain and muscle IL-8 gene expression quadratically increased (p ≤ 0.01), with MED having greatest gain and gene expression. Ribeye area tended to quadratically increase with Cu supplementation within RAC (p = 0.08). In vitro basal lipolytic rate tended to quadratically increase with Cu supplementation within RAC (p = 0.11), while stimulated lipolytic rate tended to linearly increase within NoRAC (p = 0.10). These data suggest lipolysis and the BA response of steers are influenced by dietary and liver Cu concentrations