The Impact of Pre-Slaughter Fasting on the Ruminal Microbial Population of Commercial Angus Steers

Abstract

Diet impacts the composition of the ruminal microbiota; however, prior to slaughter, cattle are fasted, which may change the ruminal microbial ecosystem structure and lead to dysbiosis. The objective of this study was to determine changes occurring in the rumen after pre-slaughter fasting, which can allow harmful pathogens an opportunity to establish in the rumen. Ruminal samples were collected before and after pre-slaughter fasting from seventeen commercial Angus steers. DNA extraction and 16S rRNA gene sequencing were performed to determine the ruminal microbiota, as well as volatile fatty acid (VFA) concentrations. Microbial richness (Chao 1 index), evenness, and Shannon diversity index all increased after fasting (p ≤ 0.040). During fasting, the two predominant families Prevotellaceae and Ruminococcaceae decreased (p ≤ 0.029), whereas the remaining minor families increased (p < 0.001). Fasting increased Blautia and Methanosphaera (p ≤ 0.003), while Campylobacter and Treponema tended to increase (p ≤ 0.086). Butyrate concentration tended to decrease (p = 0.068) after fasting. The present findings support that fasting causes ruminal nutrient depletion resulting in dysbiosis, allowing opportunistic pathogens to exploit the void in the ruminal ecological niche.

Iron sulfate and molasses treated anthocyanin-rich black cane silage improves growth performance, rumen fermentation, antioxidant status, and meat tenderness in goats

“…However, it cannot exclude the possibility that greater anthocyanin consumption decreased rumen solubility of dietary proteins, which in turn decreased rumen ammonia-N concentrations [ 9 ]. Also, the above result could be affected by the 24 h fasting before slaughtering and collection of rumen fluid [ 16 ] used in this study. After 24 h of fasting, rumen fermentation may be quite mild and not reflecting its true potential [ 16 ].…”

“…Also, the above result could be affected by the 24 h fasting before slaughtering and collection of rumen fluid [ 16 ] used in this study. After 24 h of fasting, rumen fermentation may be quite mild and not reflecting its true potential [ 16 ]. It is unfortunate that the present study did not provide data to explain for anthocyanin induced protein solubility reduction, thus more research is needed on this interesting subject.…”

“…At the completion of the 90-d feeding trial, all the 32 goats were slaughtered. Prior to slaughtering, the final BW of goats were taken and feed were withdrawn for 24 h before being transferred to the university’s slaughterhouse facility for slaughtering and collection of rumen fluid samples [ 16 ].…”

Campylobacter jejuni Response When Inoculated in Bovine In Vitro Fecal Microbial Consortia Incubations in the Presence of Metabolic Inhibitors

“…It is not clear whether Campylobacter can become established in the mature rumen, but there is evidence that it can survive under certain circumstances such as in the presence of protozoa [35]. Campylobacter have also been shown to exhibit a trend to increase in the rumens of beef cattle undergoing preslaughter fasting [39]. The factors that influence the presence of Campylobacter in the rumen are unclear but 16S rDNA microbiome taxonomic data from previous poultry in vitro cecal incubation studies detected a potential inverse relationship between methanogens and Campylobacter [40].…”

Fecal Microbiome Differences in Angus Steers with Differing Feed Efficiencies during the Feedlot-Finishing Phase

“…where d is the sample mean difference, µ d 0 is the hypothesized population mean difference, s d = Sd/ √ n , n is the number of samples differences, and Sd is the standard deviation of the sample differences [25]. All results were considered significant when p ≤ 0.05 and were treated as trends when 0.05 < p ≤ 0.10.…”