Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
Population Medicine And Diagnostic Sciences
Non Technical Summary
The dairy industry is under constant pressure for maximal productivity and efficient utilization of resources. Our ultimate goal is to improve lactational performance by modulating homeorhesis and promoting metabolic health during the transition period. We have developed a recombinant bovine interleukin 8 (rIL-8) with the initial goal of mitigating the incidence of uterine diseases. After an initial clinical evaluation using a single intrauterine infusion with rIL-8 immediately after parturition we noticed improvements uterine health parameters but more interestingly, milk production increased by 3.6 kg/day during the first six months of lactation. We have replicated the results of this initial clinical trial on a second similar study that used 3 different doses of intrauterine IL8. To investigate the potential mechanism of action we performed a study with 31 days old bull calves where we injected them with rIL-8 and measured insulin sensitivity at various time points. Systemic administration of rIL-8 induced strong and long lasting insulin resistance in the studied calves. Insulin resistance is an important homeorhetic adaptation for milk production and the only effective pharmaceutical currently available to enhance milk production in dairy cows (rBST, Posilac, Elanco) is known to act by inducing insulin resistance. Therefore, the objectives of this study is to evaluatethe long-term whole-bodyinsulin response after rIL-8 treatment in Holstein dairy cows.The specific aims is to determine the long-term whole-body and tissue-specific changes in insulin response after rIL-8 treatment.This study will be conducted at the Cornell Dairy Research Center located in Harford, NY (http://ansci.cals.cornell.edu/about-us/facilities). The experimental farm has the capacity to house 80 cows in a tie-stall barn equipped with sawdust bedding, ad libitum access to water, and completely separated feed bunks that allows for accurate evaluation of individual feed intake. Additionally, 486 lactating cows can be housed in a free-stall barn with separate pens for primiparous and multiparous animals, sand bedding, fans, and ad libitum access to feed and water. At the first signs of delivery, cows will moved to individual maternity pens where trained farm personnel will assist with parturition as needed. Within 12 hours of parturition (0 days in milk; DIM), Holstein cows (n= 60) will be randomly allocated in one of two treatments. Cows assigned to the rIL-8 group (rIL-8, n= 30) will receive a subcutaneous (SQ) injection in the neck with 0.07 mg of rIL-8; whereas those assigned to the control group (CON, n= 30) will receive a SQ injection in the neck of saline solution.Peripheral response to insulin and glucose disappearance will be evaluated using GTT and IC in all cows enrolled in the study at 120 and 122 DIM.
Animal Health Component
30%
Research Effort Categories
Basic
70%
Applied
30%
Developmental
(N/A)
Goals / Objectives
Determine the long-term whole-body and tissue-specific changes in insulin response after rIL-8 treatment. Long-term whole-body response to insulin and glucose disappearance will be evaluated through GTT (120 DIM) and IC (122 DIM) in all cows enrolled in the study. Sequential blood samples will be collected to determine the temporal changes in circulating glucose, insulin, and NEFA (i.e. IC only).
Project Methods
Aim:Determine the long-term whole-body and tissue-specific changes in insulin response after rIL-8 treatment.Peripheral response to insulin and glucose disappearance will be evaluated using GTT and IC in all cows enrolled in the study. An indwelling jugular catheter (14 G; Hospira, Sligo, Ireland) will be placed at 119 and 121 DIM (Figure 6). GTT will be performed at 120 and IC at 122 DIM. Cows will be fasted for 1 hour prior to each test. For the GTT, cows will be infused with 0.25 g/kg of BW of glucose (dextrose 50%, wt/vol; Phoenix Scientific Inc., St. Joseph, MO) followed by 20 mL of sterile saline solution. Blood will be sampled at -15, 0, 15, 30, 45, 60, 90, and 120 relative to glucose infusion. For the IC, cows will be infused with 0.2 IU of insulin/kg of BW (Eli Lilly and Co., Indianapolis, IN) followed by 20 mL of sterile saline solution. Blood samples will be collected at at -15, 0, 15, 30, 45, 60, 90 and 120 minutes relative to insulin infusion. Blood will be collected into evacuated tubes containing sodium fluoride and potassium oxalate (Vacutainer, Becton Dickinson, Franklin Lakes, NJ). Samples will be placed on ice immediately and centrifuged at 2,000 × g for 15 minutes at 4oC within 1 hour of collection. Plasma will be harvested and stored at −20oC until assayed. Concentrations of glucose, insulin, and NEFA (i.e. IC only) will be evaluated as described below. Concentrations at -15, -5, and 0 minutes relative to glucose or insulin infusion will be averaged and used as baseline value. Results from both tests will be analyzed considering each time point as a repeated measure and by the accumulated area under the curve (AUC) calculated using the trapezoidal method at 30 minutes, 60 minutes, and at the end of the collection period.