Effects of sodium monensin and melengestrol acetate on dry matter intake, rumen fermentation, short chain fatty acids absorption and total tract barrier function of cannulated cows

• Grant number: 13/25440-3
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: January 15, 2014
• End date: April 14, 2014
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Danilo Domingues Millen
• Grantee: Ana Carolina Janssen Pinto
• Supervisor: Gregory B. Penner
• Host Institution: Universidade Estadual Paulista (UNESP). Campus Experimental de Dracena. Dracena , SP, Brazil
• Institution abroad: University of Saskatchewan (USASK), Canada
• Associated to the scholarship: 13/11597-8 - Effects of different doses of sodium monensin on morphological and histological parameters of rumen epithelium of feedlot Nellore cattle, BP.IC

Abstract

The objectives of this study are to evaluate the effect of monensin and melengesterol acetate on dry matter intake (DMI), rumen fermentation with new contributions including short chain fatty acids (SCFA) absorption and total tract barrier function. The study will be conducted in the University of Saskatchewan, Canada. It will be used four cannulated cows in a Latin square design with a 2 x 2 factorial arrangement of treatments. Factors will be inclusion or not of MON or MGA, at a dose of 330 mg*kg1 of dry matter or at 170 mg*kg1 of dry matter, respectively. The study will have 84 days, and then each period will last 21 days: 14 days of adaptation to the diets and 7 days to collect data and samples. The 7 days collection period will be planned as following: Day 1 to 3: Continuous rumen pH measurement and spot samples (every 9 h) for SCFA concentrations; Day 4 to 6: total tract barrier function; Day 7: temporarily isolated washed reticulum-rumen technique for SCFA absorption. Dry matter intake will be measured every day and ruminal pH data will be recorded by using an indwelling continuous pH measurement system positioned at the bottom of the cranial-ventral sac. Barrier function will be accessed using Cr-EDTA as a paracellular permeability marker, and urine samples will be used for determination of Cr concentration using atomic absorption spectrometry. Absorption of SCFA and lactate will be measured using the isolated and washed reticulum-rumen technique, and using gas chromatography will perform analysis of SCFA and lactate concentrations. (AU)