Quantitative risk assessment model of the presence of porcine epidemic diarrhea and African swine fever viruses in spray-dried porcine plasma.

Introduction: There are no microbiological regulatory limits for viruses in animal feed and feed ingredients. Methods: A performance objective (PO) was proposed in this study to manufacture a spray-dried porcine plasma (SDPP) batch absent of any infectious viral particles. The PO levels of -7.0, -7.2, and -7.3 log TCID50/g in SDPP were estimated for three batch sizes (10, 15, and 20 tons). Results and discussion: A baseline survey on the presence of porcine epidemic diarrhea virus (PEDV) in raw porcine plasma revealed a concentration of -1.0 ± 0.6 log TCID50/mL as calculated using a TCID50-qPCR derived standard curve. The mean African swine fever virus (ASFV) concentration in raw plasma was estimated to be 0.6 log HAD50/mL (0.1-1.4, 95% CI) during a pre-clinical scenario (collected from asymptomatic and undetected viremic pigs). Different processing scenarios (baseline: spray-drying + extended storage) and baseline + ultraviolet (UV) radiation were evaluated to meet the PO levels proposed in this study. The baseline and baseline + UV processing scenarios were >95 and 100% effective in achieving the PO for PEDV by using different batch sizes. For the ASFV in SDPP during a pre-clinical scenario, the PO compliance was 100% for all processing scenarios evaluated. Further research is needed to determine the underlying mechanisms of virus inactivation in feed storage to further advance the implementation of feed safety risk management efforts globally.

Safety of dietary nitrate supplementation by calcium nitrate for finishing pigs as measured by methemoglobin and serum and tissue nitrate levels.

Nitrate supplementation has been studied as a beneficial constituent of the human diet, particularly for its effects on vascular health through vasodilation. Recent studies have focused on the benefits of nitrate supplementation in animals, especially in swine. Up to 1,200 mg/kg dietary nitrate supplementation from Ca nitrate was beneficial in farrowing and lactating sows and their offspring, and up to 6,000 mg/kg supplemental nitrate showed no adverse health effects in sows or piglets. Controlled study data evaluating the safety of nitrate supplementation to growing swine of any weight class is scant. Therefore, an experiment was conducted to test the hypothesis that increased inclusion rates of dietary nitrate through the addition of Ca nitrate in diets would not influence concentrations of nitrate or nitrite in serum and tissue, nor blood hemoglobin and methemoglobin. Forty-eight individually housed pigs (initial weight 119.1 ±â€…5.3 kg) were randomly allotted to four dietary treatments containing 0, 500, 1,000, or 2,000 mg/kg dietary nitrate and fed experimental diets for 28 d. Growth performance was not influenced (P > 0.10) by dietary treatment. The most sensitive safety endpoint, methemoglobin, did not change (P > 0.10) with dietary nitrate exposure up to 2,000 mg/kg. Serum and tissue nitrate and nitrite levels, myoglobin, and hemoglobin were not adversely affected (P > 0.10). Total myoglobin in the loin linearly increased (P < 0.05) with greater dietary nitrate in the diet, which is correlated with the red color of meat. This work established the safety of up to 2,000 mg/kg dietary nitrate from Ca nitrate as an ingredient in food for finishing pigs.

Unexpected thermal stability of two enveloped megaviruses, Emiliania huxleyi virus and African swine fever virus, as measured by viability PCR.

BACKGROUND: The particle structure of Emiliania huxleyi virus (EhV), an algal infecting member of nucleocytoplasmic large DNA viruses (NCLDVs), contains an outer lipid membrane envelope similar to that found in animal viruses such as African swine fever virus (ASFV). Despite both being enveloped NCLDVs, EhV and ASFV are known for their stability outside their host environment. METHOD: Here we report for the first time, the application of a viability qPCR (V-qPCR) method to describe the unprecedented and similar virion thermal stability of both EhV and ASFV. This result contradicts the cell culture-based assay method that suggests that virus "infectivity" is lost in a matter of seconds (for EhV) and minutes (for ASFV) at temperature greater than 50 °C. Confocal microscopy and analytical flow cytometry methods was used to validate the V-qPCR data for EhV. RESULTS: We observed that both EhV and ASFV particles has unprecedented thermal tolerances. These two NCLDVs are exceptions to the rule that having an enveloped virion anatomy is a predicted weakness, as is often observed in enveloped RNA viruses (i.e., the viruses causing Porcine Reproductive and Respiratory Syndrome (PRRS), COVID-19, Ebola, or seasonal influenza). Using the V-qPCR method, we confirm that no PRRSV particles were detectable after 20 min of exposure to temperatures up to 100 °C. We also show that the EhV particles that remain after 50 °C 20 min exposure was in fact still infectious only after the three blind passages in bioassay experiments. CONCLUSIONS: This study raises the possibility that ASFV is not always eliminated or contained after applying time and temperature inactivation treatments in current decontamination or biosecurity protocols. This observation has practical implications for industries involved in animal health and food security. Finally, we propose that EhV could be used as a surrogate for ASFV under certain circumstances.

Comparison of growth performance and tissue cobalt concentrations in beef cattle fed inorganic and organic cobalt sources.

Cobalt is an essential trace mineral required for ruminal vitamin B12 synthesis, but sources differ in ruminal microbial utilization, i.e., cobalt carbonate is poorly water soluble, whereas acetate and lactate forms are water soluble. Reports comparing organic cobalt lactate to other cobalt salts are lacking. The study objective was to determine if feeding cobalt lactate at two inclusion rates resulted in similar growth performance and tissue cobalt concentrations as the carbonate and acetate forms used in feeds. One hundred Angus cross bred steers weighing 385 ±â€…20 kg were randomly assigned to one of five treatments. Cattle were fed a basal diet plus: 1) cobalt carbonate to supply cobalt at 30 mg/steer/d, 2) cobalt acetate to supply cobalt at 30 mg/steer/d, 3) cobalt acetate to supply cobalt at 60 mg/steer/d, 4) cobalt lactate to supply cobalt at 30 mg/steer/d, and 5) cobalt lactate to supply cobalt at 60 mg/steer/d. Cattle were fed according to industry standards until body fat deposition was visually deemed to grade USDA Choice, which was 92 and 117 d for each of the 2 blocks, respectively. Steers were harvested and carcass measurements recorded along with sampling of adipose, heart, kidney, liver, and muscle for tissue cobalt concentrations. Three statistical contrasts consisted of: 1: inorganic (cobalt carbonate) vs. organic (cobalt acetate and lactate); 2: cobalt acetate vs. cobalt lactate; and 3: feeding rate of 30 vs. 60 mg/steer/d cobalt. Body weight gains, average daily gains, dry matter intake, and feed conversions were similar (P > 0.10) for steers fed all cobalt sources and feeding rates. Hot carcass weight, yield grade, back fat thickness, and ribeye area were similar (P > 0.10) among steers fed all cobalt sources and inclusion rates. Liver, kidney, muscle, and adipose cobalt concentrations were similar (P > 0.08) for steers fed inorganic vs. organic cobalt sources. Feeding cobalt lactate compared with cobalt acetate did not affect (P > 0.10) liver, kidney, heart, muscle, and adipose tissue cobalt concentrations. Feeding 60 mg/steer/d cobalt compared with 30 mg/steer/d increased (P < 0.01) liver, kidney, heart, and adipose tissue cobalt concentrations, while muscle was a tendency (P < 0.06). The study demonstrated that feeding soluble cobalt lactate, a new cobalt source, resulted in similar growth performance, carcass characteristics, and tissue cobalt concentrations when compared with cobalt acetate and carbonate.

Survival of a surrogate African swine fever virus-like algal virus in feed matrices using a 23-day commercial United States truck transport model.

African swine fever virus (ASFV) is a member of the nucleocytoplasmic large DNA viruses (NCLDVs) and is stable in a variety of environments, including animal feed ingredients as shown in previous laboratory experiments and simulations. Emiliania huxleyi virus (EhV) is another member of the NCLDVs, which has a restricted host range limited to a species of marine algae called Emiliania huxleyi. This algal NCLDV has many similar morphological and physical characteristics to ASFV thereby making it a safe surrogate, with results that are applicable to ASFV and suitable for use in real-world experiments. Here we inoculated conventional soybean meal (SBMC), organic soybean meal (SBMO), and swine complete feed (CF) matrices with EhV strain 86 (EhV-86) at a concentration of 6.6 × 107 virus g-1, and then transported these samples in the trailer of a commercial transport vehicle for 23 days across 10,183 km covering 29 states in various regions of the United States. Upon return, samples were evaluated for virus presence and viability using a previously validated viability qPCR (V-qPCR) method. Results showed that EhV-86 was detected in all matrices and no degradation in EhV-86 viability was observed after the 23-day transportation event. Additionally, sampling sensitivity (we recorded unexpected increases, as high as 49% in one matrix, when virus was recovered at the end of the sampling period) rather than virus degradation best explains the variation of virus quantity observed after the 23-day transport simulation. These results demonstrate for the first time that ASFV-like NCLDVs can retain viability in swine feed matrices during long-term transport across the continental United States.

Rethinking the uncertainty of African swine fever virus contamination in feed ingredients and risk of introduction into the United States.

Economically relevant pathogens, such as African swine fever virus (ASFV), have been shown to survive when experimentally inoculated in some feed ingredients under the environmental conditions in transoceanic transport models. However, these models did not characterize the likelihood of virus survival under various time and temperature processes that feed ingredients undergo before they are added to swine diets. Here, we developed a quantitative risk assessment model to estimate the probability that one or more corn or soybean meal ocean vessels (25,000 tonnes) contaminated with ASFV would be imported into the United States annually. This final probability estimate was conditionally based on five likelihoods: the probability of initial ASFV contamination (p0), ASFV inactivation during processing (p1) and transport (p2), recontamination (pR), and ASFV inactivation while awaiting customs clearance at United States entry (p3). The probability of ASFV inactivation was modelled using corn and soybean (extruded or solvent extracted) processing conditions (times and temperatures), D-values (time to reduce 90% or 1-log) estimated from studies of ASFV thermal inactivation in pork serum (p1), and survival in feed ingredients during transoceanic transport (p2 and p3). 'What-if' scenarios using deterministic values for p0 and pR (1%, 10%, 25%, 50%, 75%, and 100%) were used to explore their impact on risk. The model estimated complete inactivation of ASFV after extrusion or solvent extraction processes regardless of the initial ASFV contamination probability assumed. The value of recontamination (ranging from 1% to 75%) was highly influential on the risk of one ASFV-contaminated soybean meal vessel entering the United States. Median risk estimates ranged from 0.064% [0.006%-0.60%; 95% probability interval (PI)], assuming a pR of 1.0%, up to 4.67% (0.45%-36.50% 95% PI) assuming a pR of 75.0%. This means that at least one vessel with ASFV-contaminated soybean meal would be imported once every 1563-21 years, respectively. When all raw corn was assumed to be contaminated (p0 = 100%), and no recontamination was assumed to occur (pR = 0%), the median probability of one vessel with ASFV-contaminated corn entering the United States was 2.02% (0.28%-9.43% 95% PI) or once every 50 years. Values of recontamination between 1% and 75% did not substantially change the risk of corn. Days of transport, virus survival during transport (D-value), and number of vessels shipped were the parameters most influential for increased likelihood of a vessel with ASFV-contaminated soybean meal or corn entering the United States. The model helped to identify knowledge gaps that are most influential on output values and serves as a framework that could be updated and parameterized as new scientific information becomes available. We propose that the quantitative risk assessment model developed in this study can be used as a framework for estimating the risk of ASFV entry into the United States and other ASFV-free countries through other types of imported feed ingredients that may potentially become contaminated. Ultimately, this model can be used to develop risk mitigation strategies and critical control points for inactivating ASFV during feed ingredient processing, storage, and transport, and contribute to the design and implementation of biosecurity measures to prevent the introduction of ASFV into the United States and other ASFV-free countries.

Can we effectively manage parasites, prions, and pathogens in the global feed industry to achieve One Health?

Prions and certain endoparasites, bacteria, and viruses are internationally recognized as types of disease-causing biological agents that can be transmitted from contaminated feed to animals. Historically, foodborne biological hazards such as prions (transmissible spongiform encephalopathy), endoparasites (Trichinella spiralis, Toxoplasma gondii), and pathogenic bacteria (Salmonella spp., Listeria monocytogenes, Escherichia coli O157, Clostridium spp., and Campylobacter spp.) were major food safety concerns from feeding uncooked or improperly heated animal-derived food waste and by-products. However, implementation of validated thermal processing conditions along with verifiable quality control procedures has been effective in enabling safe use of these feed materials in animal diets. More recently, the occurrence of global Porcine Epidemic Diarrhea Virus and African Swine Fever Virus epidemics, dependence on international feed ingredient supply chains, and the discovery that these viruses can survive in some feed ingredient matrices under environmental conditions of trans-oceanic shipments has created an urgent need to develop and implement rigorous biosecurity protocols that prevent and control animal viruses in feed ingredients. Implementation of verifiable risk-based preventive controls, traceability systems from origin to destination, and effective mitigation procedures is essential to minimize these food security, safety, and sustainability threats. Creating a new biosafety and biosecurity framework will enable convergence of the diverging One Health components involving low environmental impact and functional feed ingredients that are perceived as having elevated biosafety risks when used in animal feeds.

New perspectives for evaluating relative risks of African swine fever virus contamination in global feed ingredient supply chains.

There are no published reports indicating that the African swine fever virus (ASFV) has been detected in feed ingredients or complete feed. This is primarily because there are only a few laboratories in the world that have the biosecurity and analytical capabilities of detecting ASFV in feed. Several in vitro studies have been conducted to evaluate ASFV concentration, viability and inactivation when ASFV was added to various feed ingredients and complete feed. These inoculation studies have shown that some feed matrices support virus survival longer than others and the reasons for this are unknown. Current analytical methodologies have significant limitations in sensitivity, repeatability, ability to detect viable virus particles and association with infectivity. As a result, interpretation of findings using various measures may lead to misleading conclusions. Because of analytical and technical challenges, as well as the lack of ASFV contamination data in feed supply chains, quantitative risk assessments have not been conducted. A few qualitative risk assessments have been conducted, but they have not considered differences in potential scenarios for ASFV contamination between various types of feed ingredient supply chains. Therefore, the purpose of this review is to provide a more holistic understanding of the relative potential risks of ASFV contamination in various global feed ingredient supply chains and provide recommendations for addressing the challenges identified.

Use of acceptable daily intake (ADI) as a health-based benchmark in nutrition research studies that consider the safety of low-calorie sweeteners (LCS): a systematic map.

BACKGROUND: It is well-recognized that consumers face many challenges in understanding and applying nutritional guidance for low-calorie sweeteners (LCS). Thus, this research aims to (1) assess how benchmarks for safe levels of consumption of LCS are utilized by researchers, and (2) understand how varying use of such benchmarks may contribute to challenges in understanding and applying nutritional guidance for LCS consumption. METHODS: A systematic mapping exercise was employed to characterize when and how acceptable daily intake (ADI) values are used as health-based benchmarks in nutrition research studies that consider the safety of LCS. RESULTS: Based on results from charting 121 studies, our findings demonstrate that comparisons of LCS intake to an ADI derived by an authoritative body have been made in a diverse set of published literature, varying widely in their objectives, approaches, and populations of interest. The majority of studies compared the ADI to intake in a population under study; these represent the type of comparison that is most consistent with the intent of the ADI. Other applications of the ADI included use as a benchmark in experimental studies, risk-benefit analyses, and metabolism studies. CONCLUSION: Although most instances of ADI use were reasonable within the context of the individual studies' objectives, the diversity in use by original-study authors amplifies the continued need for development of "best practices" regarding the use and interpretation of the ADIs in current research. Using comparisons to the ADI can be a helpful way to provide context to research findings. However, in doing so, it is important that researchers utilize the value in a manner specific with its intent, as the ADI is a metric that represents an estimate of the amount of a substance that can be consumed daily over a lifetime without presenting an appreciable risk to health.

Impact of calcium nitrate supplementation on the oxygen-carrying capacity of lactating sows and their offspring.

Calcium nitrate supplementation has recently been suggested to provide potential benefits to sows and, in particular, their offspring when administered at a level of 1,200 ppm in feed shortly before farrowing through lactation. More specifically, nitrate supplementation has been suggested as one opportunity for improved placental and/or fetal blood flow and has been hypothesized in previous work to be important to the swine industry in light of the global trend toward larger litter sizes. The benefit is likely manifested through exposure to the nitrate moiety, but interestingly, nitrate has historically been considered a compound of concern for swine. High levels of nitrate once metabolized to nitrite can interfere with the oxygen-carrying capacity of hemoglobin, resulting in increased methemoglobin and, subsequently, methemoglobinemia (MetHb) if the animal is deprived of significant amounts of oxygen; however, the level of nitrate exposure necessary to induce MetHb in sows is not clearly defined. This work was undertaken to examine methemoglobin levels in sows and piglets exposed to the potentially beneficial levels of 1,200 and 6,000 ppm nitrate added to their diets over the course of the periparturient period. Other oxygen capacity blood variables were evaluated (e.g., hemoglobin, hematocrit, and various measures of hemoglobin and red blood cell volumes and concentrations), as well as performance endpoints (weight changes and feed intake) and general observations over the 27-d period. No evidence of treatment-related toxicity manifestation was observed at these supplemental levels. Nearly all oxygen-related variables were affected by time (independent of treatment), indicating adaptive general effects of farrowing. These findings support the hypothesis that MetHb is not a concern up to at least 6,000 ppm supplemental nitrate exposure, even in combination with additional nitrate in the sow's daily diet. This work is important to help swine producers understand that consideration of nitrate benefit should outweigh concern for risk of nitrate-induced toxicity.

A 90-day oral (dietary) toxicity and mass balance study of corn starch fiber in Sprague Dawley rats.

The potential toxicity of corn starch fiber was assessed and compared to polydextrose, a commonly used bulking agent with a long history of safe use in the food supply. Groups of male and female Crl:CD(SD) rats were fed 0 (control), 1,000, 3,000, or 10,000 mg/kg-bw/day corn starch fiber in the diet for 90 days. The polydextrose reference article was offered on a comparable regimen at 10,000 mg/kg-bw/day. Following a single gavage dose of [14C]-corn starch fiber on study day 13 or 90, the mass balance of the test article was assessed by analysis of excreta samples collected from 0 to 168 h post-dose. There were no toxicologically or biologically relevant findings in any of the test article-treated groups. The few minor differences observed between the corn starch fiber and polydextrose exposed groups were considered to be due to normal biological variation. Following [14C]-corn starch fiber dosing, nearly complete excretion of the administered dose occurred over 168 h post-dosing, with the majority excreted in the feces. The dietary no-observed-adverse-effect level of corn starch fiber after 90 days was 10,000 mg/kg-bw/day. Similar toxicity profiles for corn starch fiber and polydextrose were observed due to the structural and compositional similarities of these materials.

Evaluation of the gastrointestinal tolerability of corn starch fiber, a novel dietary fiber, in two independent randomized, double-blind, crossover studies in healthy men and women.

Two independent clinical studies were conducted to compare the gastrointestinal (GI) tolerability of corn starch fiber, a novel dietary fiber, at up to 50 g/day (single-dose study) or 90 g/day (multiple-serving study) with a negative control (no fiber) and a positive control (50 or 90 g polydextrose, for single- and multiple-serving studies, respectively) in generally healthy study volunteers. Flatulence and borborygmus were the primary symptoms reported at the higher doses of corn starch fiber and for the positive control interventions. Bowel movements were increased over 48 h with corn starch fiber at 90 g. Thresholds for mild GI effects were established at 30 g as a single dose and 60 g as multiple servings spread over the day. Other than moderate abdominal pain and mild increased appetite in one subject at 90-g corn starch fiber, no test article-related adverse events were reported.