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Demographic information of students in introductory animal science courses allows instructors to tailor content to student needs and interests. This study compared student demographics with student perceptions of livestock production practices. Students in two introductory animal science sections (section A: n = 310, section B: n = 328) participated in a pre-course and a post-course survey. Both sections were comprised primarily of first-year undergraduate students; a majority was female with either horse experience or no livestock experience. Thirty percent of section A and 58% of section B was enrolled in the College of Agriculture. Forty percent of section A and 60% of section B had prior 4-H or FFA involvement. Pre-course, the sections disagreed on whether horses are pets or livestock, how media portrays agriculture, and whether slaughterhouse practices are humane. Post-course, more of section A than section B considered horses as livestock, and both sections agreed that media negatively portrays agriculture, weather has the greatest influence on producer success, and slaughterhouse practices are humane. These results suggest that students with no livestock experience may view agriculture differently than students with experience, but more exposure to livestock production issues may challenge students to evaluate their views of agriculture. [ABSTRACT FROM AUTHOR]

Previous studies have determined that stress causes decreases in feed intake and efficiency in livestock, but the effect of repeated transport on these parameters has not been well studied. This study determined how repeated transport affected calf post-transport behavior, feed intake, ADG, and feed conversion. Thirty-six 4-mo-old Holstein steer calves were housed in groups of 6 with each group randomly assigned to either transport or control treatments. Each calf was assigned to an individual Calan gate feeder and feed intake was recorded daily. Transport calves were transported for 6 h in their groups in a 7.3 by 2.4 m gooseneck trailer divided into 3 compartments, at an average density of 0.87 m2/calf, every 7 d for 5 consecutive weeks. After return to their home pens, behavior was recorded for transported calves at 5-min intervals for 1 h. Calf ADG and feed conversion were analyzed in a mixed model ANOVA, whereas feed intake was analyzed as a repeated measure in a mixed model ANOVA. Post-transport, calves followed a pattern of drinking, eating, and then lying down. The highest (82 ± 5% calves) and lowest (0 ± 5% calves) incidences of eating behavior occurred 10 and 60 min post-transport, respectively. Control calves had a higher feed intake than transported calves overall (7.29 ± 0.22 kg for control and 6.91 ± 0.21 kg for transport; P = 0.01), for the feeding posttreatment (6.78 ± 0.27 kg for control and 6.01 ± 0.28 kg for transport; P = 0.007), and the day after treatment (7.83 ± 0.23 kg for control and 7.08 ± 0.15 kg for transport; P = 0.02). Feed intake for the feeding post-transport for transport calves significantly decreased after the second transport but increased with each successive transport (P < 0.0001). Overall, control calves had higher ADG than transported calves (1.34 ± 0.13 kg/d for control and 1.15 ± 0.12 kg/d for transport; P = 0.006). No significant difference (P = 0.12) between treatments was detected for feed conversion. These results suggest that calves exposed to repeated transport may decrease feed intake compared to nontransported calves as an initial response to transport; however, overall feed conversion was not affected and these Holstein calves may have quickly acclimated to repeated transport. [ABSTRACT FROM AUTHOR]

Some natural environments on Earth are characterised by high levels of radiation, including naturally radioelement enriched mineral springs in the French Massif Central. Therefore, naturally radioactive mineral springs are interesting ecosystems for understanding how bacterial populations in these springs have adapted to high levels of natural and chronic radioactivity over the very long term. The aim of this study was to analyse the bacterial communities of sediments from five naturally radioactive mineral springs in the French Massif Central, sampled in autumn 2019 and spring 2020, and to observe whether radionuclides, compared to other physicochemical parameters, are drivers of the bacterial community structuring in these extreme environments. Physicochemical measurements showed that two springs, Dourioux and Montagne had high radioelement concentrations/activities (uranium, thorium and radon). Analysis of the structure of the bacterial communities, by next generation sequencing based on 16S rRNA gene sequencing, showed that the presence of radionuclides in Dourioux and Montagne, did not lead to a reduction in bacterial diversity and richness compared to the other springs. However, Dourioux and Montagne were characterised by specific bacterial populations, whose presence correlates with the radioelement concentrations/activities measured in these springs. This suggests that radioelements could partly explain the structuring of bacterial communities in these springs. In addition, several of these operational taxonomic units (OTUs) specific to Dourioux and Montagne, mainly affiliated to Proteobacteria , Firmicutes , Acidobacteria , Actinobacteria , and Bacteroidetes , could be involved in the biogeochemistry of radionuclides through different mechanisms (biosorption, biomineralisation, bioaccumulation, and bioreduction), which would allow the development of other bacterial species sensitive to these metals/radioelements. In particular, the co-occurrence of sulphate and/or iron-reducing bacteria, capable of bioreducing uranium, with fermentative bacteria, releasing sources of organic carbons, reflects associations of bacteria with complementary functions that allow them to grow in this peculiar environment and maintain a high diversity in these extreme environments. This study has provided a better understanding of the structuring of bacterial communities exposed to ionising radiation for thousands of years in naturally radioactive environments., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Holub, Sergeant, Bailly, Beauger, Breton, Chardon, Montavon, Vesvres and Mallet.)

This study aimed to assess the potential impact of long-term chronic exposure (69 years) to naturally-occurring radionuclides (RNs) and heavy metals on microbial communities in sediment from a stream flowing through a watershed impacted by an ancient mining site (Rophin, France). Four sediment samples were collected along a radioactivity gradient (for 238 U368 to 1710 Bq.Kg -1 ) characterized for the presence of the bioavailable fractions of radionuclides ( 226 Ra, 210 Po), and trace metal elements (Th, U, As, Pb, Cu, Zn, Fe). Results revealed that the available fraction of contaminants was significant although it varied considerably from one element to another (0 % for As and Th, 5-59 % for U). Nonetheless, microbial communities appeared significantly affected by such chronic exposure to (radio)toxicities. Several microbial functions carried by bacteria and related with carbon and nitrogen cycling have been impaired. The high values of fungal diversity and richness observed with increasing downstream contamination (H' = 4.4 and Chao1 = 863) suggest that the community had likely shifted toward a more adapted/tolerant one as evidenced, for example, by the presence of the species Thelephora sp. and Tomentella sp. The bacterial composition was also affected by the contaminants with enrichment in Myxococcales, Acidovorax or Nostocales at the most contaminated points. Changes in microbial composition and functional structure were directly related to radionuclide and heavy metal contaminations, but also to organic matter which also significantly affected, directly or indirectly, bacterial and fungal compositions. Although it was not possible to distinguish the specific effects of RNs from heavy metals on microbial communities, it is essential to continue studies considering the available fraction of elements, which is the only one able to interact with microorganisms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Nisin is an antimicrobial polypeptide inhibitory toward Gram-positive bacterial pathogens, including Listeria monocytogenes. Encapsulating nisin in lipid nanocapsules (i.e., liposomes) has been shown to protect antimicrobial functionality in complex food matrices. The capacity of liposomes to encapsulate a fluorescent reporter was determined via spectroscopy. Survival and growth of L. monocytogenes incubated in fluid milk containing 50 IU/ml free or liposome-entrapped nisin was assayed via periodic enumeration of survivors. Liposomes were formulated from phosphatidylcholine (PC) and phosphatidyl-DL-glycerol (PG) and prepared as PC, PC/PG 7/3 or PC/PG 6/4 (mol. fraction). Antilisterial activity of nisin-loaded liposomes was determined in ultra-high temperature processed fluid milk containing approximately 4.0 log10 CFU/ml L. monocytogenes Scott A plus liposomal or free nisin at 50 IU/mL. Samples were aerobically held at 5 or 20°C; L. monocytogenes were enumerated via plating after 0, 1, 3, 6, 12, 24, 48, and 72 incubation hours. Liposome entrapment did not enhance pathogen inhibition when compared to free nisin as a function of storage temperature or incubation duration.