A review on growth promoters still allowed in cattle and pig production

Dual Activation of Peroxymonosulfate Using MnFe2O4/g-C3N4 and Visible Light for the Efficient Degradation of Steroid Hormones: Performance, Mechanisms, and Environmental Impacts

Single activation of peroxymonosulfate (PMS) in a homogeneous system is sometimes insufficient for producing reactive oxygen species (ROS) for water treatment applications. In this work, manganese spinel ferrite and graphitic carbon nitride (MnFe2O4/g-C3N4; MnF) were successfully used as an activator for PMS under visible light irradiation to remove the four-most-detected-hormone-contaminated water under different environmental conditions. The incorporation of g-C3N4 in the nanocomposites led to material enhancements, including increased crystallinity, reduced particle agglomeration, amplified magnetism, improved recyclability, and increased active surface area, thereby facilitating the PMS activation and electron transfer processes. The dominant active radical species included singlet oxygen (1O2) and superoxide anions (O2•-), which were more susceptible to the estrogen molecular structure than testosterone due to the higher electron-rich moieties. The self-scavenging effect occurred at high PMS concentrations, whereas elevated constituent ion concentrations can be both inhibitors and promoters due to the generation of secondary radicals. The MnF/PMS/vis system degradation byproducts and possible pathways of 17β-estradiol and 17α-methyltestosterone were identified. The impact of hormone-treated water on Oryza sativa L. seed germination, shoot length, and root length was found to be lower than that of untreated water. However, the viability of both ELT3 and Sertoli TM4 cells was affected only at higher water compositions. Our results confirmed that MnF and visible light could be potential PMS activators due to their superior degradation performance and ability to produce safer treated water.

Insights in the Development and Uses of Alternatives to Antibiotic Growth Promoters in Poultry and Swine Production

The overuse and misuse of antibiotics has contributed to the rise and spread of multidrug-resistant bacteria. To address this global public health threat, many countries have restricted the use of antibiotics as growth promoters and promoted the development of alternatives to antibiotics in human and veterinary medicine and animal farming. In food-animal production, acidifiers, bacteriophages, enzymes, phytochemicals, probiotics, prebiotics, and antimicrobial peptides have shown hallmarks as alternatives to antibiotics. This review reports the current state of these alternatives as growth-promoting factors for poultry and swine production and describes their mode of action. Recent findings on their usefulness and the factors that presently hinder their broader use in animal food production are identified by SWOT (strength, weakness, opportunity, and threat) analysis. The potential for resistance development as well as co- and cross-resistance with currently used antibiotics is also discussed. Using predetermined keywords, we searched specialized databases including Scopus, Web of Science, and Google Scholar. Antibiotic resistance cannot be stopped, but its spreading can certainly be hindered or delayed with the development of more alternatives with innovative modes of action and a wise and careful use of antimicrobials in a One Health approach.

Modeling the effects of steroid implant use on the environmental and economic sustainability of Brazilian beef production

Brazilian beef systems contribute 14.9% of global beef production, therefore given climate change concerns, there is a clear need to reduce environmental impacts while maintaining economic viability. This study evaluated the hypothesis that steroid implant use in Brazilian beef cattle would reduce resource use, greenhouse gas (GHG) emissions and economic costs of production, thereby improving environmental and economic sustainability. A deterministic model based on beef cattle population demographics, nutrition and performance was used to quantify resource inputs and GHG emissions per 1.0 × 106 kg of hot carcass weight (HCW) beef. System boundaries extended from cropping input manufacture to cattle arriving at the slaughterhouse. Beef systems were modeled using herd population dynamics, feed and performance data sourced from producers in four Brazilian states, with additional data from global databases. Implants were used in calves, growing and finishing cattle at low (LI), medium (MI), and high (HI) levels of performance enhancement, compared to nonimplanted (NI) controls. Feed use results were used in combination with producer-derived input costs to assess the economic impacts of implant use, including production costs and returns on investment. Improved FCE, ADG, and carcass weights conferred by implant use reduced the number of cattle and the time taken to produce 1.0 × 106 kg HCW beef. Compared to NI controls, the quantities of feed, land, water and fossil fuels required to produce 1.0 × 106 kg HCW beef was reduced in implanted cattle, with reductions proportional to the performance-enhancing effect of the implant (HI > MI > LI). Implant use reduced GHG emissions per 1.0 × 106 kg HCW beef by 9.4% (LI), 12.6% (MI), or 15.8% (HI). Scaling up the MI effects to represent all eligible Brazilian cattle being implanted, revealed avoided GHG emissions equivalent to the annual exhaust emissions of 62.0 × 106 cars. Economic impacts of implant use reflected the environmental results, resulting in a greater margin for the producers within each system (cow-calf through to finishing). The 6.13% increase in kg of HCW beef produced generates a cost reduction of 3.76% and an increase in the return on invested capital of 4.14% on average. Implants offer the opportunity for Brazilian beef producers to demonstrate their dedication to improving environmental and economic sustainability through improved productivity, although care must be taken to avoid negative trade-offs.

Efficacy of Hormonal Growth Promoter Implants on the Performance of Grazing Steers of Different Breeds in Southern Chile

Increasing demands for land is necessitating the optimisation of grazing land used for livestock production. Hormonal growth promoter implants (HGPI) are widely used to improve cattle performance and thus land-use efficiency. However, there is limited information on their efficacy in grazing systems. Forty grazing steers, 10 of each breed (Angus, Hereford, Holstein, Overo Colorado), had growth rates monitored for 85 days after which half received HGPI and half continued as a control. Growth rates were monitored for an additional 61 days and performance between the groups compared. Implants had a significant impact on liveweight gain (LWG; p = 0.013), and whilst breed did not (p = 0.65), there was an interaction effect of breed × treatment (p = 0.029). For three of the four breeds, the LWG was greater in the implant group (mean +14.3%). The exception was for Holstein steers which did not respond to the implant. In general, HGPI were found to be effective in increasing LWG of grazing cattle and thus has the potential to increase yield densities and relieve pressures of land use and competition. The efficacy may be affected by breed and other extraneous factors not covered in this study. Furthermore, the use of HGPI must be carefully considered in a wider context since its use might have secondary impacts.