Feed Batches Research Articles

Weighted Bayesian network for the classification of unbalanced food safety data: Case study of risk-based monitoring of heavy metals.

Historical data on food safety monitoring often serve as an information source in designing monitoring plans. However, such data are often unbalanced: a small fraction of the dataset refers to food safety hazards that are present in high concentrations (representing commodity batches with a high risk of being contaminated, the positives) and a high fraction of the dataset refers to food safety hazards that are present in low concentrations (representing commodity batches with a low risk of being contaminated, the negatives). Such unbalanced datasets complicate modeling to predict the probability of contamination of commodity batches. This study proposes a weighted Bayesian network (WBN) classifier to improve the model prediction accuracy for the presence of food and feed safety hazards using unbalanced monitoring data, specifically for the presence of heavy metals in feed. Applying different weight values resulted in different classification accuracies for each involved class; the optimal weight value was defined as the value that yielded the most effective monitoring plan, that is, identifying the highest percentage of contaminated feed batches. Results showed that the Bayesian network classifier resulted in a large difference between the classification accuracy of positive samples (20%) and negative samples (99%). With the WBN approach, the classification accuracy of positive samples and negative samples were both around 80%, and the monitoring effectiveness increased from 31% to 80% for pre-set sample size of 3000. Results of this study can be used to improve the effectiveness of monitoring various food safety hazards in food and feed.

Designing a monitoring program for aflatoxin B1 in feed products using machine learning

Agricultural commodities used for feed and food production are frequently contaminated with mycotoxins, such as Aflatoxin B1 (AFB1). In Europe, both the government and companies have monitoring programs in place for the presence of AFB1. With limited resources and following risk-based monitoring as prescribed in EU Regulation 2017/625, these monitoring programs focus on batches with the highest probability of being contaminated. This study explored the use of machine learning algorithms (ML) to design risk-based monitoring programs for AFB1 in feed products, considering both monitoring cost and model performance. Historical monitoring data for the presence of AFB1 in feed products (2005–2018; 5605 records in total) were used. Four different ML algorithms, including Decision tree, Logistic regression, Support vector machine and Extreme gradient boosting (XGB), were applied and compared to predict the high-risk feed batches to be considered for further AFB1 sampling and analysis. The monitoring cost included the cost of: sampling and analysis, disease burden, storage, and of recalling and destroying contaminated feed batches. The ML algorithms were able to predict the high-risk batches, with an AUC, recall, and accuracy higher than 0.8, 0.6, and 0.9, respectively. The XGB algorithm outperformed the other three investigated ML. Its incorporation would result into up to 96% reduction in monitoring cost in 2016–2018, as compared to the official monitoring program. The proposed approach for designing risk based monitoring programs can support authorities and industries to reduce the monitoring cost for other food safety hazards as well.

APPAREND AND TRUE METABOLIZABLE ENERGY OF HIGH PROTEIN SUNFLOWER MEAL IN BALANCE EXPERIMENTS WITH ROOSTERS

Aim: To establish the zero nitrogen corrected apparent (AMEn-o) and the true (TMEn-o) metabolizable energy of two batches high – protein (dehulled, with 45 and 50% crude protein in DM) sunflower meal. Material and Methods: Standardized methods for balance experiments with poultry. The roosters were 1 year old – White Plymouth Rock – race. Six birds were tube fed and six feed deprived per each batch of fodder. Separately experiments with intact and caecoectomized roosters were conducted. Results: The following levels (J/g DM) have been established: Batch 45%: (AMЕn-o): intact: 8430, caecoectomized: 8317, mean: 8373; (TMЕn-o): intact: 9221, caecoectomized: 9108, mean: 9164. For the batch 50% the results were: 9281, 10061, mean - 96711 and 9943, 10973, mean - 10458 J/g DM respectively. Conclusion: The authors suggest that both feed batches can replace isoenergetic soybean meal in combined fodders for poultry.

Current challenges in the diagnosis of zearalenone toxicosis as illustrated by a field case of hyperestrogenism in suckling piglets

BackgroundThe mycotoxin zearalenone (ZEN) causes functional and morphological alterations in reproductive organs of pigs. In the field, diagnosis of ZEN-induced disorders is often challenging, as relevant feed lots are no longer available, or feed analysis results are not conclusive. Here, we report a field case of hyperestrogenism in newborn piglets. Surprisingly, more than 50 fungal metabolites were detected in hay pellets fed to gestating sows, including ZEN and its modified form zearalenone-14-sulfate (ZEN-14-S). Despite the broad contamination range in this unconventional feed component, a definite diagnosis of mycotoxicosis could not be achieved. In this context, current limitations regarding the confirmation of suspected cases of ZEN-induced disorders are discussed, covering both feed analysis and the biomarker approach.Case presentationA piglet producer with 200 sows experienced a sudden increase in suckling piglet losses up to 30% by lower vitality and crushing. Predominant clinical signs were splay legs and signs of hyperestrogenism such as swollen and reddened vulvae in newborn piglets. The first differential diagnosis was ZEN mycotoxicosis although feed batches had not been changed for months with the exception of ground hay pellets, which had been included in the diet five months before. Analysis of hay pellets resulted in a sum value of ZEN and its modified forms of more than 1000 μg/kg, with ZEN-14-S alone accounting for 530 μg/kg. Considering the inclusion rate of 7% in the diet for gestating sows, the severe impact of the additional ZEN load due to the contaminated hay pellets seemed unrealistic but could not be completely excluded either. One month after hay pellets had been removed from the diet no further clinical signs were observed.ConclusionsEnrichment materials and other fibre sources can contain significant amounts of mycotoxins and should be therefore included in feed analysis. Adequate methods for broad spectrum mycotoxin determination, including modified mycotoxins, are important. As highlighted by this field case, there is a need to establish reliable biomarkers for ZEN exposure in pigs. Currently, available biomarkers do not allow a solid prediction of the ZEN intake of pigs under field conditions, which limits their application to experimental studies.

Closed circuit desalination of O&G produced water: An evaluation of NF/RO performance and integrity

Reclamation and reuse of oil and gas (O&G) waste streams is being considered as an option to alleviate stress on freshwater supplies. While limited treatment is necessary to reuse O&G wastewater (e.g., produced water (PW)) for subsequent hydraulic fracturing, high removal of organic matter and total dissolved solids (TDS) is needed to enable broader reuse (e.g., irrigation, stream flow augmentation). This study focused on the use of closed circuit desalination with nanofiltration (NF) and reverse osmosis (RO) to remove TDS and organic matter from pretreated PW. The performance and fouling propensity of three commercial NF and RO membranes was compared during the concentration of ~900 feed batches (440 h). Up to 99.6% TDS and 89% dissolved organic carbon (DOC) was removed, producing high quality permeate. Membrane characterization revealed minimal scaling and organic fouling of the three membranes, suggesting that closed circuit desalination (CCD) might be a promising method to facilitate reuse of PW.

A cross-sectional field study on potential associations between feed quality measures and usage of antimicrobials in commercial mink (Neovison vison)

Feed quality is generally assumed to affect health status in animal production. In previous studies, the feed producer has been found to affect the occurrence of gastrointestinal disease and antimicrobial use in Mink (Neovison vison). Mink are fed with moist, freshly produced feed, based on perishable ingredients. The objective of this study was to investigate the potential effect of specific feed parameters on antimicrobial use on herd level. The study was cross-sectional, including 1472 mink herds, responsible for 97% of oral antimicrobials prescribed for Danish mink during the study period, 2012–2014. Data were obtained from the national veterinary prescription database (VetStat), Kopenhagen Fur database, and the Voluntary Feed Control (Mink producers Organization). All feed batches subject to feed control were included. A multi-variable variance analysis was carried out analysing the effect of the feed parameters total volatile nitrogen, dry matter, crude protein and fat; total bacterial count (21°C), and counts of sulphite producing bacteria (21°C), Clostridium spp., faecal cocci (FC) (44°C), yeast, and mould; presence of Salmonella spp. and Clostridium perfringens (dichotome). Three outcome variables were applied: prescription of oral antimicrobial on herd level within time slots of 3, 5 or 7days after feeding of an included batch. Two binomial models were developed, adjusting for significant effects (p<0.0001) of Ps. aeruginosa infection, herd size, month (season) and year. Antimicrobial prescription was significantly (p<0.0001) associated with FC (all time slots, both models). A negative association (p<0.0001) with crude protein on antimicrobial prescription within a 7day slot suggested an association between low content of crude protein and antimicrobial use. The associations need to be confirmed in controlled studies, and ideally, potential causalities should be investigated. The perspective of such findings could be the development of tests for control of feed ingredients prior to use in the feed production.

Dynamic population balance and flow models for granular solids in a linear vibrating screen

Vibrating screens are a widely applied form of particle separations. In spite of this significance, their understanding is still an obstacle. Three approaches were used to characterize the flow of granular material in a linear vibrating screen. The statistical model, mass action, and kinetic model based on conservation of momentum were derived. Experiments were then conducted on a multi‐sized prototype screen and glass beads of sizes 0.75, 1, 2, 3 mm. Deck inclinations were varied over 7.5,12.5, and 17.5°, and frequencies over 7, 15, and 20 Hz. A total of 72 feed batches and a constant power of 50 W was used. The experimental data was then used to validate the models. The three models provided accurate flow prediction over the screens. Additionally, the kinetic model also provided a basis for optimal design of the screening unit operation, by allowing manipulation of seven design variables to obtain a 95–100% efficient vibrating screen. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3889–3898, 2016

Nonlinear optimization of gravity solids classification based on the feed and deck angles: a law of mass action approach

Deck screen design parameters e.g. material of construction, deck angle of inclination, the feed throughputs, and physicochemical properties of the particles, are critical factors to consider in solids classification. Two significant and easily manipulated parameters that greatly affect screen performance are the feed rate and design geometry configuration. In this work we apply statistical analysis of variance (ANOVA) and nonlinear least squares optimization with parameter estimation concepts, first, to assess the significance of the two factors and, second to formulate flow prediction models that optimize the feed rate and classification efficiency. Experiments were conducted on a prototype screen of 556.28cm2 effective area, (1380cm2 total area). For glass beads of sizes 0.75, 1, 2, and 3mm, with 16 feed batches of 10g to 160g, and six inclination angles 5, 10, 12.5, 15, 17.5, and 20°, a maximum efficiency of 66.7% was achieved with a screen loading of 86.5g, and an inclination angle of 17.5°. These results were then subjected to nonlinear least squares optimization, which showed that a maximum efficiency of 93.2% can be achieved at batch loading as low as 36g. There was a favorable performance at the range of angles 12.5≤θ≤17.5°, but poor performance outside this range. The screening efficiency did not respond significantly to changes in screen loading, although loading had a significant effect on the screening capacity. Confirmation tests conducted at selected optimum parameters achieved a maximum efficiency of 72% (at 12.5° with 49.6g batch load), and a maximum rate of 27g/s at 17.5° with 104g.

О КОНТАМИНАЦИИ МИКОТОКСИНАМИ СЕНАЖА И СИЛОСА В ЖИВОТНОВОДЧЕСКИХ ХОЗЯЙСТВАХ

Improvement of sanitary control of grass fodder, taking into account the whole variety of factors that have a negative impact on the animal, is the most important task of agricultural science. In the present study, we investigated mycotoxin contamination of hayage and silage by the method of indirect competitive enzyme-linked immunosorbent assay. In a survey of 30 commercial feed batches from the livestock farms located in the central regions of the European Russia, namely Bryanskya, Lipetskaya, Moskovskaya, Smolenskaya and Tverskaya provinces, a multiple contamination pattern was shown. In all the samples eight or more mycotoxins were found, and more than half of samples contained 14-15 components. Alternariol was found in all samples of the both types of feeds in amounts from 50 to 1260 mg/kg, while aflatoxin В 1 ochratoxin A, citrinin and ergot alkaloids had extensive distribution with low intensity. In haylage with high incidence of all analyzed fusariotoxins, mass concentration of Т-2 toxin was the lowest (4 to 30 mg/kg), and the levels of diacetoxyscirpenol, deoxynivalenol, zearalenone and fumonisins were in the range of 100-1000 mg/kg. Sterigmatocystin, emodin, cyclopiazonic and mycophenolic acids, PR-toxin occurred everywhere, wherein emodin, cyclopiazonic acid and PR-toxin often present in amounts up to 1000 mg/kg. Silage prepared mainly from corn grass, with frequent detection of T-2 toxin and deoxynivalenol in significant content (to 350 and 2820 mg/kg, respectively) revealed similarities with corn grain from the center of European Russia. Sterigmatocystin and emodin were detected in all silage samples, whereas PR-toxin, cyclopiazonic and mycophenolic acids were slightly inferior to them in frequency. Levels of accumulation of these mycotoxins were lower than those found in silage, and for mycophenolic acid they generally remained the same. A botanical composition of herbage and features of toxin-producing fungi complexes, accompanying the growing season and the subsequent process of fermentation, are discussed among possible reasons for the differences in mycotoxin contamination of haylage and silage.

MYCOTOXIN CONTAMINATIONS IN COMMERCIALLY USED HAYLAGE AND SILAGE

Improvement of sanitary control of grass fodder, taking into account the whole variety of factors that have a negative impact on the animal, is the most important task of agricultural science. In the present study, we investigated mycotoxin contamination of hayage and silage by the method of indirect competitive enzyme-linked immunosorbent assay. In a survey of 30 commercial feed batches from the livestock farms located in the central regions of the European Russia, namely Bryanskya, Lipetskaya, Moskovskaya, Smolenskaya and Tverskaya provinces, a multiple contamination pattern was shown. In all the samples eight or more mycotoxins were found, and more than half of samples contained 14-15 components. Alternariol was found in all samples of the both types of feeds in amounts from 50 to 1260 µg/kg, while aflatoxin Â1, ochratoxin A, citrinin and ergot alkaloids had extensive distribution with low intensity. In haylage with high incidence of all analyzed fusariotoxins, mass concentration of O-2 toxin was the lowest (4 to 30 µg/kg), and the levels of diacetoxyscirpenol, deoxynivalenol, zearalenone and fumonisins were in the range of 100-1000 µg/kg. Sterigmatocystin, emodin, cyclopiazonic and mycophenolic acids, PR-toxin occurred everywhere, wherein emodin, cyclopiazonic acid and PR-toxin often present in amounts up to 1000 µg/kg. Silage prepared mainly from corn grass, with frequent detection of T-2 toxin and deoxynivalenol in significant content (to 350 and 2820 µg/kg, respectively) revealed similarities with corn grain from the center of European Russia. Sterigmatocystin and emodin were detected in all silage samples, whereas PR-toxin, cyclopiazonic and mycophenolic acids were slightly inferior to them in frequency. Levels of accumulation of these mycotoxins were lower than those found in silage, and for mycophenolic acid they generally remained the same. A botanical composition of herbage and features of toxin-producing fungi complexes, accompanying the growing season and the subsequent process of fermentation, are discussed among possible reasons for the differences in mycotoxin contamination of haylage and silage.

A new general method for designing affinity chromatography processes

Affinity chromatography is widely used for selectively recovering a target solute from a complex mixture. The challenge in designing a capture process is to achieve high yield, high column utilization, and high sorbent productivity while satisfying loading time and pressure limit requirements. The conventional design method based on constant-pattern waves cannot be used for small feed batches or short columns, which do not allow the formation of such waves. Other design methods in the literature rely on simulations or experimental trials, and can be time-consuming and costly. In this study, a new design method with no need of simulations is developed for constant pattern and non-constant pattern systems with Langmuir isotherms. Given feed conditions, loading time, and desired yield, the design requires only the values of certain intrinsic parameters, which can be estimated from a small number of bench-scale experiments. The minimum column volume for capture can be estimated either graphically or analytically. The method is tested with Protein A chromatography data for antibody purification. It is applicable to a wide range of production scales and design requirements. The effects of material properties, feed composition, feed volume, and design requirements on the column volume for capture can be found graphically. When the loading time relative to a characteristic diffusion time is 0.5 or larger, the minimum column volume approaches that of an ideal system. A short loading time increases sorbent productivity, but increases the minimum column volume. A high feed concentration, a high equilibrium capacity, and a small diffusion time relative to the loading time can reduce the minimum column volume and increase productivity.

Effect of fermented moist feed on performance, gut bacteria and gut histo-morphology in broilers

1. Fermented feed has been shown to be beneficial in pig nutrition as a tool to reduce gut microbial disorders. Experiments with fermented feed in poultry are scarce, probably because of the belief that wet feed is less suitable for this species and causes wet litter.2. A total of 280 one-d-old Ross 308 chickens were used in a completely randomised design with two dietary treatments (7 replicates of 20 birds/treatment); air-dry feed versus the same feed in moist form (water:feed ratio of 1.3:1, on a weight basis), inoculated with Lactobacillus plantarum NCIMB 40087 (9 log10 CFU/kg feed) and batch-fermented for 48 h at 26°C. The birds were given starter (d 0–13), grower (d 4–26) and finisher (d 27–39) diets ad libitum. At the end of the grower and finisher period, two birds per pen were removed to sample intestinal contents for cultivating bacteria and intestinal tissue to determine villus height and crypt depth.3. Fermented moist feed (FMF) batches showed good characteristics, with a pH between 3.9 and 4.4 and DL-lactic acid between 137 and 286 mmol/l. Daily feed intake and gain were reduced considerably in the FMF group in the starter (–40 and –44%, respectively) and grower (–23 and –16%) period, though in the finisher period these birds performed better, with an improved feed utilisation. Concomitant with the latter, villus height at the mid-jejunum and mid-ileum on d 39 was higher (+22.6% and +16.0%). Significantly more Lactobacilli and less coliforms were found in the foregut and less Streptococci in ileum and caeca of birds given FMF.4. This trial showed that FMF was detrimental for early bird growth but affected beneficially feed efficiency, the composition of the gut bacteria and villus height in the small intestine in the finisher period in broilers.

Carry-over of veterinary drugs from medicated to non-medicated feeds in commercial feed manufacturing plants

Different compound feeds have to be manufactured in the same production line. As a consequence, traces of the first produced feed may remain in the production and get mixed with the next feed batches. This “carry-over” is unavoidable, and so non-medicated feed can be contaminated with veterinary drugs like antibiotics added to the previous batch of medicated feed. To monitor the carry-over of antibiotics in the Netherlands, 21 feed mills were visited and 140 samples of flushing feeds were collected and analysed for containing residues of antibiotics. Results show that 87% of all samples contain concentrations of antibiotics in the range of 0.1–154 mg/kg. It is expected that these levels – which are in the same range as previously found for the nowadays banned antimicrobial growth promoters (AMGPs) – have an effect on the occurrence of microbial resistance. Analysis of a second set of samples collected at four different feed mills directly after the production of oxytetracycline-medicated feed demonstrated that the first part of a flushing feed has much higher contamination than the last part of the batch. Furthermore, it was demonstrated that the carry-over percentage shows no correlation with the carry-over determined by one of the standard GMP+ procedures. These observations, unavoidable carry-over, inhomogeneous batches of feed with antibiotics and difficulties to predict the carry-over levels, together with the awareness of the increasing problem of microbial resistance, motivated the NEVEDI, association of Dutch Feed Producers, to announce that they will voluntarily stop the production of medicated feed in 2011. The alternatives for medicated feed are for example water or milk medication or the use of top-dressings at the farm. The consequences and possible new risks of carry-over at the farm are not completely clear yet.

Effects of exogenous enzymes on apparent nutrient digestibility in rainbow trout (Oncorhynchus mykiss) fed diets with high inclusion of plant-based protein

Plant-based protein ingredients are increasingly used in feed for carnivorous fish as replacement for fish meal. This study investigated if supplementing diets with high inclusion levels of plant-based protein with three different enzymes could improve the apparent nutrient digestibility in juvenile rainbow trout (Oncorhynchus mykiss). Three diets with high inclusion levels of either de-hulled, solvent extracted soybean meal (344g/kg), sunflower meal (246g/kg), or rapeseed meal (264g/kg) were produced and feed batches were coated post-extrusion with the different enzymes: β-glucanase at 67mg/kg, xylanase at 208mg/kg, protease at 228mg/kg, or a combination of the three enzymes at the same doses. Three consecutive digestibility trials were carried out using a flow-through, modified Guelph System. Each trial was designed to include five dietary treatment groups: a non-supplemented control diet and 4 diets supplemented with either β-glucanase, xylanase, protease or a combination of the three enzymes. Diets were fed to triplicate tanks and two faecal sampling periods for digestibility measurements for each tank were scheduled. Each experiment comprised a 10-day digestibility trial succeeded by a water sampling period for measuring the dissolved nitrogen (N) output. Each experiment lasted 17–19 days in total.Apparent digestibility coefficients (ADCs) of protein, fat, ash, phosphorus and dry matter (DM) were derived from the three digestibility trials, along with calculations of the specific growth rate (SGR, %/d) and feed conversion ratio (FCR). Nitrogen mass-balance and energy retention were evaluated for each dietary treatment group to elucidate on the utilization of digested nutrients and energy.Enzyme supplementation had only moderate effect on apparent nutrient digestibility in the sunflower and rapeseed experiments, while β-glucanase and protease improved the apparent digestibility of all dietary nutrients in the soybean experiment (P<0.05). The effect was more pronounced for lipid than for other nutrients. β-Glucanase had a positive effect on energy retention in the soybean experiment (P<0.05), while there were no effects on nitrogen retention or fish performance in any of the three experiments (P>0.05) during the short feeding periods. The study thus provides preliminary results on the potential of β-glucanase and protease to increase apparent nutrient digestibility of soybean meal in fish feed.

PERFIL SOROLÓGICO E DE ISOLAMENTO DE Salmonella sp. EM SUÍNOS NO INÍCIO DA TERMINAÇÃO E AO ABATE

Studies assessing the Salmonella transmission chain in pig herds are the first step to start a control program. The aims of this study were to compare the prevalence of Salmonella positive pigs at the beginning of the finishing phase and at slaughter, and to identify the possible sources of contamination in the farms. In three finishing farms, environmental swabs from the barns and from the feed silos were collected during the sanitary emptiness. Furthermore, samples of feces and blood from the animals on the day of housing; and aliquots from all feed lots were taken. At slaughter, blood, mesenteric lymph nodes (LM) and intestinal content (CI) were sampled. Blood samples were submitted to a S. Typhimurium ELISA-LPS test. All other samples were submitted to a Salmonella isolation protocol. Feed samples were also submitted to Polymerase Chain Reaction (PCR) targeting the invA gene. Feces samples from all pigs were Salmonella negative at the beginning of the finishing phase, in two farms seropositive animals were found. In two farms, residual environmental contamination was detected, and, in the third farm, one of the feed batches was Salmonella positive on the PCR assay. At slaughter, over 90% of the animals were positive on the ELISA-LPS test and, in all cohorts, a variable number (12%-92%) of carriers in LM and CI was detected. From this on, it was concluded that the finishing phase was critical for the amplification of Salmonella infection, and the residual environmental contamination in the farms as well as Salmonella positive feed batches were the probable infection sources. KEY WORDS: Isolation, finishing and slaughter, Salmonella, serology, swine.

The Feed Factor: Estrogenic Variability in Lab Animal Diets

Animal studies have long been a cornerstone of biomedical and environmental health research, and scientists need assurance that animals used in these studies are being cared for in ways that will not unknowingly influence experimental outcomes. But a growing number of scientists have voiced concern over the possibility that certain estrogenic compounds present in lab animal feed may skew test results. These compounds are deemed potentially problematic because they can bind to estrogen receptors and induce estrogen-like effects in animals, humans, and cells grown in culture. Some experts have advocated strict standardization of rodent chows and even the removal of dietary phytoestrogens. This emergent controversy was the focus of “DIET II—The Effect of Variability in Estrogenic Activity of Commercial Animal Feeds: Interaction with Manufacturers, NIH Officials, and Scientific Societies to Develop a Solution,” a full-day meeting held 3 August 2006 in Research Triangle Park, North Carolina. The meeting, the second in a series on the topic, was cosponsored by the NIEHS and the NIH Office of Dietary Supplements (ODS). Discussions at the meeting centered on the variation in estrogenic activity between feed batches, the effects of these estrogenic components on endocrine-related end points, and the difficulties inherent in comparing, interpreting, and reproducing these end points over time within and between different laboratories when background levels of diet-related estrogenic activity are not adequately documented. Findings presented at this meeting made it clear that researchers studying estrogen-related end points can not afford to overlook the influence of the test rodent’s diet. “This workshop is an excellent example of the cumulative and self-correcting nature of the scientific process,” said ODS nutritionist Elizabeth Yetley, a conference co-organizer. “That is, through the accumulation of results from a body of experimental evidence, the importance of approaches for better-defined animal diets relative to their potential estrogenic activity have been identified, and measures to improve future research in this area are being undertaken by the scientific community.” Participants at the conference—organized by NIEHS scientists Jerrold Heindel and Julius Thigpen, along with Yetley and University of Missouri–Columbia biologist Frederick vom Saal—included investigators from the endocrine disruptor research community as well as representatives from animal feed companies. This spectrum of representatives reflected the fact that, in Heindel’s words, “researchers and animal care divisions of research institutions are beginning to pay attention to the phytoestrogen issue, and feed manufacturers want to know what the scientific community wants.” Heindel described a sincere interest on the part of both sides to reach a “win–win” solution, one that would yield animal diets of a known estrogenicity that could be used by researchers in all fields of physiology and toxicology, but that also would not unduly burden the feed manufacturers.

Strategies to Control Batch Integrity in Size-Exclusion Simulated Moving Bed Chromatography

In pharmaceutical production, it is important to link each batch of product to its source materials and track each batch throughout the production process. Tracking and controlling each batch is more challenging in a simulated moving bed (SMB) process than in conventional batch chromatography. Solutes coming from a certain feed batch in an SMB can be mixed with solutes coming from adjacent feed batches. The mixing is due to the location of the product ports relative to the feed port, periodic port movement, internal recycle, and dispersion due to mass transfer resistances. The degree of mixing, or the size of the overlap region of the different batches in the product stream, largely depends on solute residence time. Decreasing the zone lengths, using partial feeding, or applying pinched wave operating conditions can effectively reduce residence time and therefore decrease the overlap region. To eliminate the overlap region completely (or achieve complete control of batch integrity), an eluent gap can be applied between two adjacent feed batch injections. The strategies for reducing residence time can minimize the eluent gap, thereby reducing eluent consumption and increasing productivity. One can further reduce the amount of eluent by closing the feed port during the gap period and opening the feed port only during the feed loading period.

Mixing and clean-out properties of sulfamethazine and carbadox in swine feed (1995)

Two forms of sulfamethazine (pelleted and granular) and one form of carbadox (granular) were evaluated for their mixing and clean-out properties in replicated batches of swine feed prepared at the research feed mill at Kansas State University. Analysis of variance indicated that carbadox was incorporated into the feed more uniformly than sulfamethazine. Additional mixing beyond 1.5 minutes did not improve drug distribution (P>0.05). A paired-comparison T-test was used to compare mixing properties of drugs versus salt (the latter is commonly used to test mixer performance). We found the mixing properties of sulfamethazine and salt to be different (P 0.05). Ground corn was used to flush the mixer and conveying system between feed batches; then the mixer, leg, and sack-off bin were cleaned, and materials were assayed for drug carryover. Sulfamethazine was detected in the mixer cleanout material at concentrations of 12.6 ppm and 8.1 ppm for the granular and pellet forms, respectively. Carbadox carryover was not detected in mixer clean-out material. Detectable concentrations for all three drugs occurred in cleanout material from the leg and sack-off bin.