Red beetroot is a well-recognized and established source of bioactive compounds (e.g., betalains and polyphenols) with anti-inflammatory and antimicrobial properties. It is proposed as a potential alternative to zinc oxide with a focus on gut microbiota modulation and metabolite production. In this study, weaned pigs aged 28 days were fed either a control diet, a diet supplemented with zinc oxide (3000 mg/kg), or 2% and 4% pulverized whole red beetroot (CON, ZNO, RB2, and RB4; respectively) for 14 days. After pigs were euthanized, blood and digesta samples were collected for microbial composition and metabolite analyses. The results showed that the diet supplemented with red beetroot at 2% improved the gut microbial richness relative to other diets but marginally influenced the cecal microbial diversity compared to a zinc-oxide-supplemented diet. A further increase in red beetroot levels (4%—RB4) led to loss in cecal diversity and decreased short chain fatty acids and secondary bile acid concentrations. Also, an increased Proteobacteria abundance, presumably due to increased lactate/lactic-acid-producing bacteria was observed. In summary, red beetroot contains several components conceived to improve the gut microbiota and metabolite output of weaned pigs. Future studies investigating individual components of red beetroot will better elucidate their contributions to gut microbiota modulation and pig health.

Environmental pressures of ruminant production could be reduced by improving digestive efficiency. Previous in vivo attempts to manipulate the rumen microbial community have largely been unsuccessful probably due to the influencing effect of the host. Using an in vitro consecutive batch culture technique, the aim of this study was to determine whether manipulation was possible once the bacterial community was uncoupled from the host. Two cross inoculation experiments were performed. Rumen fluid was collected at time of slaughter from 11 Holstein-Friesian steers from the same herd for Experiment 1, and in Experiment 2 were collected from 11 Charolais cross steers sired by the same bull and raised on a forage only diet on the same farm from birth. The two fluids that differed most in their in vitro dry matter disappearance (IVDMD; “Good,” “Bad”) were selected for their respective experiment. The fluids were also mixed (1:1, “Mix”) and used to inoculate the model. In Experiment 1, the mixed rumen fluid resulted in an IVDMD midway between that of the two rumen fluids from which it was made for the first 24 h batch culture (34, 29, 20 g per 100 g DM for the Good, Mix, and Bad, respectively, P < 0.001) which was reflected in fermentation parameters recorded. No effect of cross inoculation was seen for Experiment 2, where the Mix performed most similarly to the Bad. In both experiments, IVDMD increased with consecutive culturing as the microbial population adapted to the in vitro conditions and differences between the fluids were lost. The improved performance with each consecutive batch culture was associated with reduced bacterial diversity. Increases in the genus Pseudobutyrivibrio were identified, which may be, at least in part, responsible for the improved digestive efficiency observed, whilst Prevotella declined by 50% over the study period. It is likely that along with host factors, there are individual factors within each community that prevent other microbes from establishing. Whilst we were unable to manipulate the bacterial community, uncoupling the microbiota from the host resulted in changes in the community, becoming less diverse with time, likely due to environmental heterogeneity, and more efficient at digesting DM.

Increasing global demand for food is driving the need to reduce wastes produced by agriculture to minimise environmental impacts. Black Soldier Fly, Hermetia illucens, can reduce livestock wastes, but research into the safety and scalability of the system is required. Insect bioconversion concerns include potential bioaccumulation of pathogens, antimicrobial resistance genes and heavy metals in larvae and substrates. Here, a semi-commercial-sized insect rearing facility was used to rear larvae on pig slurry, alongside a lab-based experiment using chicken manure. Larval microbiome composition was impacted by substrate, with increased Clostridia in larvae reared on slurry and manure. Pathogens largely decreased in the larvae from starting levels. Both slurry and manure substrates showed time-related changes regardless of insect presence or absence except for E. coli in chicken manure which was reduced in substrates with larvae added (-2.840 LFC vs -1.168 LFC; p<0.05), suggesting that time-associated alterations in the substrate could be more significant than larval presence. Antimicrobial resistance gene changes were dependent on the substrate and gene, with increases found for tetM in chicken manure after larval bioconversion (9.000 vs 10.370 LFC; p<0.001), and for sul2 in larvae reared on chicken manure (3.509 vs -0.985 LFC; p=0.001). In pig slurry-reared larvae, tetM decreased (-1.578 LFC; p<0.001) but there was no difference in sul2. Heavy metal contents generally met permissible standards for animal feed and organic fertilizers. However, there was some non-significant evidence for bioaccumulation of cadmium in slurry-reared larvae 0.18 to 0.70 mg/kg) compared to starter larvae (0.25mg/kg) requiring further study.

Slurry management is becoming increasingly important as countries work to decarbonise towards Net Zero goals. After feed, slurry management and application is one of the main contributors to the greenhouse gas emissions and environmental pollution associated with pork production. Whilst traditionally considered a waste product, slurry is rich in nutrients and could be harnessed to reduce environmental impacts and improve on-farm resilience. Along with reducing the environmental impacts of pork production, farmers are increasingly looking to diversify their income streams and pig slurry offers tremendous potential to achieve this. This review identifies the opportunities and challenges to the pork sector from circular, sustainable waste management systems through insect bioconversion or on-farm biogas production, with a focus on the United Kingdom. Insect bioconversion of pig slurry, through the use of Black Soldier Fly larvae, presents opportunities not only to reduce the overall volume of slurry on a farm but also to reduce heavy metal contamination, alter the microbiome and provide a myriad of additional products. These products include fertiliser in the form of insect frass, protein, oils, and chitin from the insect exoskeleton, which has applications in industries such as wastewater treatment, pharmaceuticals and healthcare. Through on-farm biogas generation, farmers, particularly those in rural areas, could reduce their reliance upon volatile energy prices and generate electricity and heat to power on-farm activities. With additional infrastructure, biogas could be upgraded to produce biofuel and CO₂ could be recovered, recycled, and sold into a variety of industries. Whilst there are still a number of outstanding questions that need to be answered and challenges that need to be addressed before the wide-scale rollout of these technologies, there is huge potential to harness the power of pig slurry. When designing the farm of the future, solutions will likely need to be tailored to an individual farm due to a range of variables including the stage of production, the number of pigs, the pig diet and the availability of co-products. However, despite these potential challenges, there is still considerable opportunity for the pork sector to harness this 'waste' product to decarbonise pig production and improve farm resilience.