MULTIDISCIPLINARY APPROACH TO IMPROVING GUT HEALTH AND FEED EFFICIENCY IN RUMINANTS

Increased demand for high-quality animal-based protein is increasing the pressure on the livestock sector to meet this growing global demand which is largely driven by increasing human population. To meet this huge demand, the livestock industry has used an assortment of feed additives to improve feed efficiency and nutrient utilization, promote growth, enhance gut health and animal welfare, and abatement of greenhouse gas emissions. The predominant practice was the administration of antibiotics at low doses (sub-therapeutic use) which consistently increased performance parameters (growth, reproduction and health) across-the-board. But this practice has been discontinued due to scientific and public concerns regarding the risk of antibiotics resistance to humans.The recent ban (at least in the U.S.) on the use of sub-therapeutic antimicrobials in ruminant production has necessitated a sense of urgency in the development of economically competitive alternatives such as plant nutraceuticals (essential oils, plant secondary metabolites, probiotics, prebiotics, and vaccines that do not compromise end-product quality. The major obstacle from using these alternatives is that results from different studies have been mixed. The consistent results with the use of sub-therapeutic antimicrobials are lacking in these alternatives. Some of the factors responsible for the mixed results with the alternatives are diet composition, dosage, type of animal, production level, enzyme activity, rumen condition, adaptation, additives-microbiome interactions, etc.Despite not having any product(s) as effective as antibiotics, the global plant nutraceutical industry continues to grow and is predicted to reach $111 billion by the end of 2023. The increase in the demand and use of plant nutraceuticals is attributed to the increasing consumer and public preferences towards wholesome meat production (preference is tilted towards no synthetic antibiotics and growth promoters use). Nutraceutical plants contain some biologically active compounds, generally phenolic-based compounds, with an ability to alter ruminal fermentation and change ruminal microflora community. Polyphenolics and essential oils are the main active components of most nutraceuticals. As stated earlier, several studies have documented the benefits of plant nutraceuticals use in livestock production but inconsistent results and short-term effect of some of these nutraceuticals need to be addressed. The short-term effect of some of these nutraceuticals in improving production and health metrics is mainly caused by adaptation of the rumen microbiome to the nutraceuticals. Nutraceuticals whose effects in improving feed efficiency and gut health (and reducing greenhouse gas emissions) are limited to a short period of time (30 days or less) are not suitable as long-term solution in ruminants. Using a blend or mixture of some promising plant nutraceuticals may be a sensible approach towards addressing the limitations associated with their use in livestock production. This is not an entire new concept as the industry already combine probiotics and prebiotics to form synbiotics. And studies have shown that synbiotics exhibited synergistic effects such as increasing the proliferation of beneficial bacteria and boosting the perpetuation of newly introduced probiotics in the host; with up to a 100-fold increase in intestinal bifido-bacteria population with the introduction of prebiotics. Additionally, a combination of a commercially available prebiotic and probiotic has been shown to eliminate morbidity and mortality losses associated with Shiga toxin-producing Escherichia coli infections in dairy calves. There are documented reports on combining probiotics and enzymes and a blend of essential oils in literature but there is a significant gap on the effect of combining different essential oils and polyphenolics.The novel idea in the proposed project is the mixing of different plant nutraceuticals that the principal investigator has evaluated previously with some levels of success. The rationale is that the effects of the nutraceutical blend will not be limited to short period of time due to adaptation of the rumen microbiome. The team will combine 9 previously researched plant nutraceuticals to formulate a blend that will have synergistic (positive) effects to increase feed efficiency and improve gut health in ruminants. To ensure that results generated can be interpreted biologically, the team will be using microbiome, metabolome and cytokine analyses (big data analytics) to validate animal productivity measurements. The big data analytics will provide additional insight into what is driving the observed changes in feed efficiency and gut health.The broad objective of the proposal is to develop a feed additive blend from 9 plant nutraceuticals (Moringa oleifera, Corymbia citriodora, Ocimum gratissimum,, Juniperus communis, brown and red onion peels, lemon grass oil, rosemary oil and algae oil) to manipulate ruminal fermentation, improve feed efficiency and animal productivity, and enhance gut health in ruminants. The proposed project aims to build on previous studies on these nutraceuticals by the team. The team will evaluate all possible combinations and ratios for these 9 nutraceuticals as synergistic and additive interactions depending on the combined ratio. We hypothesize that combining different plant nutraceuticals will enable the team to develop a superior product blend that will improve feed efficiency and gut health in ruminants. This will be addressed by following these specific objectives:1) Extract and estimate the bioactive components of 9 different plant nutraceuticals;2) Use the in vitro batch culture technique to screen different combinations of the nutraceuticals to improve feed efficiency;3) Use the rumen stimulating technique (RUSITEC) to further evaluate the different product blends;4) Evaluate the effects of three final product blends on feed intake, nutrient digestibility, rumen fermentation, and milk yield and composition of dairy cows;5) Evaluate their effects on the microbiome, metabolites and cytokines; and6) Develop a final product blend that will consistently improve feed efficiency and gut health in ruminants.