Performing Department
(N/A)
Non Technical Summary
The purpose of this research project is to determine if feeding layer hens a dairy byproduct buttermilk will change the nutritional composition of eggs, impact hen performance, and to assess the cost to benefit of this practice. The central hypothesis is that feeding buttermilk to layers will increase the nutritional value of eggs, serve as a safe feed additive without adversely affecting layer performance, and be a cost-effective feed additive. To test the hypothesis this study has the following aims: 1) Enrich egg yolks with buttermilk sourced health promoting nutrients, Sub-aim 1) Evaluate the maximum inclusion of buttermilk as a feed additive without impacting layer performance, Sub-aim 2) Evaluate the cost to benefit of utilizing buttermilk as a feed additive for layers. The expected outcome is that buttermilk sourced nutrients will accumulate within egg yolks and that there will be an optimal dietary amount of buttermilk for maximizing this enrichment in eggs. The anticipated impact is that this work will provide a basis for utilizing buttermilk as a feed ingredient for animal diets to enhance the nutritional value of animal products, improve human nutrition outcomes, and improve the sustainability of the dairy industry.
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Goals / Objectives
The primary goalof this project is to determine if dairy waste stream sourced buttermilk (BM) can be utilized as an alternative feedstuff for layers and determine if the bioactive sphingomyelin (SM) from BM can be enriched into egg yolks. The proposed project is a collaboration between UVM and Cornell University. To achieve the proposed goals in Aim 1 the animal experiment will be conducted at Cornell University. Subsequent analyses, data processing, and manuscript curation will occur at UVM.Specific Aim 1: Enrich eggs with dairy specific SM sourced from BM.Rationale: Previous layer nutritional experiments demonstrate that layer hens can absorb and deposit dietary sourced lipophilic bioactives into egg yolks in a dose dependent manner. This experiment will directly test the hypothesis that supplementing the diets of layers with dried BM will result in an accumulation of dairy-specific SM within egg yolks in a dose response without adversely affecting animal health and productionSub-Aim 1: Evaluate how dietary BM inclusion affects the production performance, health status, and egg quality of layers. The working hypothesis is that BM inclusion ranging from 2.5-10.0% of the diet will not negatively affect the production performance or long-term health status of layers. This aim will determine whether dietary dried BM impacts various health related parameters in layers including plasma biochemical indices and egg quality.Sub-Aim 2: Evaluate the cost to benefit of utilizing dried BM as a feed additive for layers. The working hypothesis is that the addition of dried BM to layer diets will decrease the cost of feeding layers and producing eggs and will increase the value of eggs to consumers. This aim will determine the cost to benefit of feeding layers dried BM and consumer acceptance of eggs from layers fed BM and their willingness to pay for this special attribute of eggs.
Project Methods
Animals, Diets, and Management. Twenty-Week-old layers will be selected and separated into four dietary treatment groups (n = 10/group) based upon body weight and egg production following a 2-week acclimation period. The number of layers per treatment group was determined based on previous layer studies with similar design. Layers will be offered one of the following diets for the 6-week experiment duration: 1.) Control - corn-soy basal with no butter milk (BM), 2.) corn-soy basal + 2.5% dried BM, 3.) corn-soy basal + 5.0% dried BM, 4.) corn-soy basal + 10.0% dried BM. The rational for using dried BM instead of liquid is that BM as a liquid would not blend well into the layer diet and interfere with proper ingredient mixing, cause spoilage at room temperature, and reduce the nutritional concentration of feed with the addition of water. The dietary amounts of dried BM are meant to determine if there is a dose response of dairy sphingomyelin(SM) enrichment into egg yolks. The justification for including up to 10% dried BM is that this amount equates to 5% lactose, an amount layers can safely consume. All diets will be formulated to be isocaloric and isonitrogenous with comparable levels of macronutrients. Diet lipids will be balanced using corn oil, carbohydrate with corn starch, and protein by adjusting amounts of corn meal, soybean meal, and celite. Experimental diets will be mixed at the Cornell research facility and stored in air-tight barrels at 4°C until being offered to hens. Representative diet samples will be collected from each batch, ground into a fine powder, and stored at −20°C for further analysis. Each layer will be in an individual cage unit in an environmentally controlled facility with 16:8 light:dark cycles maintained at 25 °C, 55% relative humidity and fed ad libitum with free access to water via nipple drinkers.Animal Performance, Sample Collection, and Analyses. Egg production and feed intake will be measured daily, and body weights measured weekly. Eggs and blood will be collected at the start of the study, at the end of week 3, and at the end of week 6 for egg component weights, shell thickness, yolk color, and subsequent analyses. Eggs will be stored in cardboard trays and kept at 4°C until broken for egg components. Egg yolks will be separated and kept frozen at −20°C until analysis. Blood will be collected via the left-wing vein with heparin treated needles and kept cold on ice until centrifugation at 3000 g for 15 minutes to separate plasma. Plasma will be stored at −20°C until analysis. Plasma will be analyzed for health parameters and general lipid profile using commercial spectrophotometric kits. Representative diet, egg yolk, and plasma samples will extracted and methylated for general FA profile utilizing previously established methodology. Egg yolk and blood samples will be prepared and analyzed for SM profile utilizing established infusion-electrospray ionization and collision-induced dissociation methodology for dairy SM modified for a Thermo LTQ Orbitrap.Plasma Biochemical Assays. Plasma biomarkers of health will be measured spectrophotometrically utilizing commercially available kits including glucose (Glucose Assay Kit, GAG020, Sigma-Aldrich Chemical Co.), uric acid (Infinity Uric Acid Liquid Stable Reagent, Thermo-Fisher Scientific, Inc.), alanine transaminase (Alanine Transaminase Reagent, Thermo-Fisher Scientific, Inc.), tartrate resistant acid phosphatase (Tartrate Resistant Acid phosphatase Reagent, Thermo-Fisher Scientific, Inc.), alkaline phosphatase (Alkaline Phosphatase Reagent, Thermo-Fisher Scientific, Inc.), and total non-esterified FA, total triglyceride, total cholesterol, and total polar lipid (Respective Lipid Enzymatic Kits, Wako Pure Chemical Industries Ltd.).Egg Quality. Condition of eggs will be recorded including those deemed broken, fractured, softshell, or otherwise abnormal. Whole eggs and components including eggshell, albumen, and yolks will be separated and weighed. Egg shell thickness will be measured in triplicate using digital calipers (Mitutoyo, Aurora, Illinois, USA) around the mid-egg equator section. Eggyolk color will be measured with a Roche color fan scale. Egg components will be measured for proximate analysis including mineral ash content of shell, protein and lipid content of albumen and yolk by a commercial laboratory (Eurofins Food Chemistry Laboratory, Madison, WI, USA).Cost to Benefit and WTP: The cost to benefit of utilizing BM to feed layers be evaluated by gathering data from local poultry businesses to determine all poultry farm cost and output components.The cost of producing liquid and dried BM including metrics such as energy inputs, equipment cost, and transportation, will be gathered from dairy producers. Consumer acceptance and WTP will be measured through consumer surveys in which participants are asked to rate or rank a set of alternative products with different product attributes. Data collected from a conjoint survey can be used to estimate the relative importance of each attribute including BM fed layers eggs and the consumer willingness to pay for each specific attribute.We plan to include the survey about BM-eggs as part of a larger study on grass-fed milk funded by USDA for 2023 to 2027.Statistical Analysis. Data will be analyzed by one-way ANOVA to test for the main effect of dietary BM inclusion on performance parameters, egg quality, yolk FA and SM content, and farm production costs and revenue, and mean comparisons will be evaluated with Duncan's multiple ranged test (R Studio, R Foundation for Statistical Computing, Vienna, Austria). Each hen will be considered an experimental unit. The significance level P < 0.05 will be used to test the hypothesis. Additional analyses including generating heatmaps and principal component analysis will be performed with MetaboAnalyst software.