Influence of oil or fat supplementation on Rumen Fermentation Characteristics and Ruminal Fluid Fatty Acid Profile in Brahman Crossbred Fattening Steers

Abstract

The aim of this experiment was to study the influence of oil or fat supplementation on rumen fermentation and ruminal fluid fatty acid profiles in Brahman crossbred steers. Twelve steers (87.5% Brahman crossbred) with average live weight (LW) of 337+54 kg and approximate age of 2 years old were stratified by their LW into 4 groups and each group was randomly assigned to four dietary treatments. All steers were fed 14% CP concentrate. The treatments included: 1) 7 kg/d concentrate, 2) 4 kg/d concentrate supplemented with 200 g/d palm oil (PO), 3) 4 kg/d concentrate supplemented with 100 g/d PO and 100 g/d linseed oil (LSO), and 4) 4 kg/d concentrate supplemented with 200 g/d LSO. The animals in treatment 1 were fed ad libitum rice straw (RS), whereas the animals in the other treatments were fed ad libitum fresh grass (FG). Results showed that the dietary treatments had no effect on nutrient intake while the oil supplements decreased dry matter intake (DMI). Feeding LSO at 2 h increased C18:3n3 and decreased C18:2n6 in ruminal fluid. Feeding LSO inhibited BH of C18:2 to C18:0, as indicated by the increased rumen flows and proportions of BH intermediates in ruminal fluid. Furthermore, LSO did not negatively influence rumen fermentation and did not change ruminal pH, NH3-N, protozoa and VFA concentration.