PSIX-13 The Impact of Saccharomyces Cerevisiae Fermentation Product on in-Vitro Rumen Fermentation Characteristics, gas Production, and Ruminal Microbiome Composition

The objective of this experiment was to evaluate the effect of Saccharomyces cerevisiae products (NaturSafe) on in-vitro rumen fermentation characteristics and microbial diversity. Three crossbred feedlot steers fitted with rumen cannulae were adjusted to a moderately high-concentrate diet for 28-d. On d-29, 1 L of rumen fluid was collected from each steer and composited. A set of vaccine bottles (n=5/treatment/time + blanks and controls) containing 0.5 g of basal diet plus dietary treatments were filled with 30 ml of rumen fluid-McDougall’s buffer solution (1:1), sealed, and placed in a 39°C water bath. Treatments consisted of 1) Control (no added NaturSafe); 2) NaturSafe-dry (9 g/animal/day equivalent); 3) NaturSafe-dry (12 g/animal/day equivalent); 4) NaturSafe-liquid (14 g/animal/day equivalent); 5) NaturSafe-liquid (21 g/animal/day equivalent); and NaturSafe-liquid (28 g/animal/day equivalent). Samples were collected at 0, 6 and 12 h post-fermentation. No treatment effect on any fermentation parameters was found at 6 h. At 12-h post-incubation, dry matter digestibility (DMD) (P < 0.04) and molar proportions of propionic acid (P < 0.03) were greater for treatments containing NaturSafe compared with control. Molar proportions of acetic acid (P < 0.07), percent CH4 (P < 0.08), and NH3-N (P < 0.06) tended to be lesser and percent CO2 tended (P < 0.07) to be greater for NaturSafe treatments compared with controls. Microbiome 16S rRNA analysis results suggest that microbial communities differed (P < 0.05) between 6 and 12 h post-incubation. Incorporating NaturSafe into fermentation vessels revealed an inverse correlation with NaturSafe concentration and microbial diversity (P = 0.08) and that the overall microbial diversity was altered (P < 0.03) by NaturSafe concentration. The microbial community was not affected by additive type. These data suggest that NaturSafe alters fermentation characteristics and microbial community diversity toward improved rumen efficiency while reducing environmental impact.

PSVI-12 Effects of polyphenols (mixed tannins) and saponin (Yucca schidigera), with or without a direct fed microbial (DFM) on in vitro rumen fermentation

Rumen fluid from fistulated steers receiving a high concentrate diet was utilized to examine the impact of polyphenols and saponin with or without a direct fed microbial (DFM) on in vitro fermentation characteristics. Treatments consisted of: Control (no polyphenols, saponin or DFM); 2) Polyphenols (Mixed Tannins = 15 g/hd/d); 3) Saponin (Y. schidigera = 2 g/hd/d); 4) Polyphenols + DFM (DFM = 1E+7 Lactobacillus animalis + 1E+8 Propionibacteria acidilactici cfu/hd/d); and 5) Saponin + DFM. Rumen fluid was collected and combined in equal amounts from 3 rumen fistulated steers and mixed at a 1:1 ratio of artificial saliva to rumen fluid. Fermentation substrate consisted of 0.5 g of the high concentrate diet. Fermentation bottles were capped with an air-tight rubber stopper and incubated in a water bath for 12 and 18h (7 replicates/treatment/time point). After incubation, the total volume of gas produced was measured and a subsample analyzed for N, CH4 and CO2 concentrations. After gas sampling, pH, VFA concentrations, and DMD were determined. In vitro fermentation parameters were analyzed using a mixed effects model repeated measures analysis for a completely randomized block design. Acetic acid was decreased while valeric acid was increased (P < 0.05) by the Saponin + DFM treatment vs. Control. At 12h DMD was greater in Saponin, Saponin + DFM and Polyphenols + DFM (P < 0.001) treatments compared to Control or Polyphenols alone. Polyphenols produced greater amounts of CH4 /DMD than all other treatments (P < 0.01). Microbial protein production and efficiency were greater (P < 0.001), Saponin + DFM compared to other treatments. Other fermentation parameters measured were not impacted by treatments. Under the conditions of this experiment these data suggest combining DFM with Saponin or Polyphenols produces different ruminal effects from when they are fed alone.

Quantification of ractopamine residues on and in beef digestive tract tissues

Ractopamine hydrochloride is a commercial beta-adrenergic agonist commonly used as a dietary supplement in cattle production for improved feed efficiency and growth promotion. Currently, regulatory target tissues (as approved in the New Animal Drug Application with Food and Drug Administration) for ractopamine residue testing are muscle and liver. However, other tissues have recently been subjected to testing in some export markets for U.S. beef, a clear disregard for scientific maximum residue limits associated with specific tissues. The overall goal of this study was to develop and validate an LC-MS/MS assay to determine whether detectable and quantifiable levels of ractopamine in digestive tract-derived edible offal items (i.e., abomasum, omasum, small intestine, and reticulum) of cattle resulted from tissue residues or residual ingesta contamination of exposed surfaces of tissues (rinsates). Tissue samples and corresponding rinsates from 10 animals were analyzed for parent and total ractopamine (tissue samples only). The lower limit of quantitation was between 0.03 and 0.66 ppb depending on the tissue type, and all tissue and rinsate samples tested had quantifiable concentrations of ractopamine. The highest concentrations of tissue-specific ractopamine metabolism (represented by higher total vs. parent ractopamine levels) were observed in liver and small intestine. Contamination from residual ingesta (represented by detectable ractopamine in rinsate samples) was only detected in small intestine, with a measured mean concentration of 19.72 ppb (±12.24 ppb). Taken together, these results underscore the importance of the production process and suggest that improvements may be needed to reduce the likelihood of contamination from residual ractopamine in digestive tract-derived edible offal tissues for market.

PSXIV-23 Characterization of microbial communities associated with the rumen lining, digesta and rumen fluid from beef cattle consuming a high energy diet using 16S rRNA gene amplicon sequencing

The true etiology of liver abscesses is not well known. Therefore, the objective of this study was to characterize the microbial communities in the rumen lining, digesta, and rumen fluid from beef cattle consuming a high energy diet, using 16S rRNA gene amplicon sequencing. Twelve crossbred feedlot steers (450 ±10 kg; ~ 3.0 years of age) fitted with ruminal fistulas, consuming a high energy finishing diet (1.43 NEg, Mcal/kg DM) for 21 d were utilized in this experiment. Microbial DNA from three regions within the rumen [rumen lining (ventral/lateral), digesta (geometric center of the rumen), and rumen fluid] was extracted and the V4 region of the 16S rRNA gene was amplified and sequenced. Across all sample regions, bacterial sequences were classified into 34 phyla, 76 classes, 143 orders, and 254 families. Bacteroidetes and Firmicutes were the predominant phyla present across all samples. The relative abundance of Bacteroidetes detected in rumen fluid was lesser (P < 0.05) when compared to bacteria sampled from the rumen lining and digesta. In contrast, the relative abundance of Firmicutes were greater (P < 0.05) in rumen fluid and the rumen lining when compared to digesta samples. There are very few publications describing the complex community of the rumen microbiome. To our knowledge this is the first publication categorizing microbial populations in three distinct locations within the rumen using next generation sequencing in feedlot cattle.

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A Comparison of Water Chilling and Air Chilling on Poultry Shelf Life

ObjectivesIn the U.S. water immersion chilling (WC) is commonly used to chill poultry, while the E.U. utilizes air chilling (AC). With demand for poultry continuing to rise, poultry products with longer shelf life and less food waste will be needed. Meanwhile, widespread efforts to reduce natural resource and energy expenditures, such as water, as a means of enhancing sustainability, exist across the meat industry, including the poultry industry. Therefore, the objective of this study was to compare the impact of WC and AC on the shelf life and meat quality of bone-in and boneless chicken breast.Materials and MethodsA total of 256 eviscerated non-chilled chicken carcasses were obtained from a commercial processing facility in California and transported to the UC Davis meat laboratory within 2 h. Carcasses were randomly and evenly assigned to either water immersion chilling (WC) or air chilling (AC) and then were evenly assigned to be fabricated into bone-in (BI) or boneless (BL) breast. The breast samples were subsequently packaged onto polystyrene trays, overwrapped, and placed into cardboard boxes for dark storage at 4°C for either 7d (phase 1) or 14d (phase 2). Then breast samples were placed into a retail display case maintained at 4°C for 3d. Instrumental color measurement was performed every 12 h during retail display. Microbial analysis was conducted for samples collected on arrival, post chilling, post-fabrication, after dark storage at 4°C for 7d or 14d and after 3d retail display (n = 10 per sampling point per treatment). A panel of 8 untrained participants were asked to evaluate the color and their willingness to purchase (for example color: desirable, acceptable, unacceptable). Analysis of variance was conducted to evaluate the effect of chilling method and storage time on all dependent variables using Proc Mixed in SAS (version 9.4).ResultsThe WC chicken possessed lower psychrotrophic bacterial counts (1.05 log CFU/g) pre-fabrication than the AC chicken (2.12 log CFU/g), indicating that WC may remove a portion of the psychrotrophic bacteria. However, no difference in mesophilic bacterial counts was observed between the two treatments for pre-fabrication samples. The WC chicken and AC chicken, regardless of fabrication type, reached the end of shelf life (7 log CFU/g) at the 14d. The BL samples, regardless of chilling method, had lower total microbial counts throughout storage and display than the BI samples, since the removal of the skin physically removed the general microbial population as well. In terms of objective color, the a* and b* values were higher for AC breast, suggesting that AC breast was more red and yellow than WC breast through the display time. Chilling method did not have an impact on subjective color measurement. During phase 1, untrained panelist considered the color of BL chicken breasts more desirable than the BI breasts. During phase 2, regardless of chilling method or fabrication type, the desirability of color by untrained panelist decreased as display time increased.ConclusionThe results indicate that chilling method had a minimal impact on the shelf life in terms of the microbial counts. Although AC chicken breast tend to be more yellow based on objective color measurement, consumers did not detect a distinct color difference of chicken treated with air chilling or water chilling.

Fluctuations in the Microbial Community and the Volatile Organic Acids Created During Aerobic Storage of Ground Beef

ObjectivesDegradation due to microbial and chemical mechanisms occurs throughout the storage life of ground beef. These pathways are intertwined and the microbial community and the volatile organic acids (VOCs) that evolve in ground beef are dynamic. Evaluation of microbial growth using traditional culture-dependent techniques can be misleading due to the presence of unculturable organisms. Therefore, utilizing culture-independent techniques allows for a more thorough understanding of the microbial community within a meat matrix during storage life. The objective of this study was to employ 16s rRNA amplicon sequencing and VOC identification using GC–MS to explore diversity and changes of the microbial community and VOC production during shelf-life of ground beef.Materials and MethodsFinely ground beef (80/20) was procured from beef processing facilities in the West (one lot) and Midwest (two lots). The lots were separated into three physically separate replicates. Ground beef lots were transported in chub packaging to Colorado State University (Fort Collins, CO), and the chubs were stored in the dark at 2°C for either 16/17 d or 23/24 d. After dark storage, chubs were reground, and 454 g fluff-packs were placed on polystyrene trays before overwrapping with polyvinyl chloride film. The trays were placed in retail display cases maintained at 2–4°C for 5 d. Samples were collected every day of retail display for evaluation of the microbial community and VOC development. Following standardized extraction, 16S rRNA amplicon sequencing was used to explore microbial communities. Sequencing data were analyzed using the programs in the QIIME2 (version 2018.4) pipeline. Similarly, volatile organic compounds were extracted prior to analysis of targeted VOCs using a GC–MS. The project was designed as a split-plot design and was analyzed using R packages (version 3.4.3), lme4, lmerTest, and emmeans. Least squares means were separated using an α of 0.05.ResultsThe top orders of bacteria found in the meat samples were from Enterobacteriales, Lactobacillales, and Pseudomonadales. No differences (P ≥ 0.05) in Faith’s Phylogenetic Diversity Index, or a measure of diversity of the bacterial species within a sample, were observed between Days 0, 2, and 4 of retail case display. A targeted analysis identified eighteen VOCs associated with ground beef spoilage. In previous studies, the presence of hexanal, acetoin and acetic acid are identified as spoilage indicators. Hexanal, Acetoin and acetic acid increased (P ≤ 0.05) over the 5 d of retail display.ConclusionThe use of 16s rRNA amplicon sequencing technology is a relatively recent tool that has rapidly advanced the study of microbial deterioration during beef storage and shelf-life. Moreover, the combination of 16s rRNA amplicon sequencing and identification of VOCs in this study, afforded an exploration of the relationship between chemical and biological changes which occur during ground beef storage. These analytical technologies, when used in unison, can highlight the dynamic relationships and evolution of chemical and biological constituents in ground beef. Further research in ground beef shelf-life should incorporate such measures.

How Muscle Foods Are Categorized and Described in Chronic Disease Literature: A Systematic Review and Quantitative Analysis (P01-021-19)

Objectives

Qualitatively, nutrition science and policy experts recognize that variation in muscle food categories (CAT) and descriptions (DESCR) hinder effective translation of research into policy. The purpose of this systematic review was to quantitatively describe CAT and DESCR patterns in nutrition-related chronic disease literature.

Methods

We identified 3427 articles in PubMed, Cochrane, and CINHAL up to March 2018. Inclusion criteria were: 1) observational (OBS) or randomized controlled trial (RCT) designs, 2) muscle food consumption as an independent variable, 3) primary prevention of cardiovascular disease, obesity, type 2 diabetes, or cancer as a dependent variable, 4) population 19+ years, and 5) females not pregnant/lactating. We considered a CAT as the phrase researchers used to refer to a muscle food group and DESCR as the explanation of a CAT. Table 1 describes our empirical scoring scale. We used generalized linear mixed models to assess effect of publication date, one-way ANOVAs to assess differences between study designs and chronic disease types, and binary logit models to estimate probabilities of DESCR factors.

Results

We identified 1019 CAT and 833 DESCR from 369 articles. Mean CAT specificity for RCT and OBS was 2 and 3 points, respectively (out of 7; Table 1), with no differences among chronic disease types. Specificity of OBS CAT was higher in more recent publications but RCT CAT became less specific in the 2000 s compared to previous years. RCT CAT were 5x more likely to include species, 6x more likely to include leanness, but 5x less likely to include processing degree compared to OBS CAT. Among all CAT, 76% and 82% included a DESCR for OBS and RCT, respectively. Researchers described processed meat, red meat, and total meat categories more commonly than poultry or fish categories. Of processed meat DESCR provided by researchers, 31% included a common term used in publicly available regulatory definitions.

Conclusions

Muscle food categories and descriptions are substantively different within and between observational and experimental studies and do not match definitions used by regulatory agencies. A practical muscle food classification system is warranted to improve interpretation of evidence regarding muscle food consumption and chronic disease.

Funding Sources

The Beef Checkoff.

Supporting Tables, Images and/or Graphs

Comparación de suadero de los Estados Unidos de América y de México con y sin tratamiento de marinación

El objetivo de este estudio fue evaluar las características sensoriales, la suavidad y la pérdida durante el cocinado del suadero marinado (MR) y sin marinar (NM) procedente de México y EE.UU. El suadero se comparó con la arrachera, ya que ésta es un corte muy demandado en forma marinada por el consumidor mexicano. Se usaron dos métodos de cocinado, uno a la parrilla (en seco) y otro al horno (con humedad). El marinado del suadero y la arrachera disminuyó la WBSF (P <0.05), con excepción del suadero procedente de EEUU cocinado a la parrilla. La arrachera marinada fue más suave que el suadero (P <0.05) independientemente del país de origen, del método de cocinado o de si estuvo o no marinado. El suadero no marinado de EEUU fue más suave que el de México (P <0.05); sin embargo, una vez marinados no hubo diferencias en la suavidad del suadero en función al país de origen (P >0.05). El panel de consumidores calificó al suadero marinado mejor en aroma, jugosidad, sabor, textura y aceptación general que el no marinado (P <0.05). El suadero marinado fue más suave cuando se cocinó en el horno con humedad, que cuando se hizo en seco en la parrilla (P <0.05). Los resultados de este estudio indican que el marinado mejora la suavidad del suadero y que el cocinado con humedad produce valores de WBSF menores que el cocinado en parrilla.