PSX-26 Ruminal bacteria and protozoa profile during adaptation and finishing periods of Nellore cattle previously submitted to either nutritional restriction or intake concentrate feedstuffs.

Abstract

The objective of this study was to evaluate the effect of nutritional restriction or consumption of concentrate ingredients prior to the adaptation period to high-concentrate diet on ruminal microorganism’s profile of cannulated Nellore cattle. The experiment was designed as a two 3 x 3 Latin squares, in which six Nellore steers (323 ± 23 kg) cannulated in the rumen were fed according to the treatments: Restriction (Tifton hay fed 1.4% BW + supplement); Control (Tifton hay fed ad libitum + supplement) and Concentrate (Tifton hay fed ad libitum + 0.5% BW of concentrate and supplement). Each period of this study lasted 33-d with two 10-d washout interval, divided as follows: 14 days of pre-adaptation (when treatments were applied), 12 days of adaptation diet (72% and 79% concentrate for 6-d each) and 7 days of finishing diet (86% concentrate). On days 17 and 29 of each period, rumen fluid was collected to evaluate populations of rumen bacteria and protozoa. Differential counting of protozoa was performed using a microscope with a reticulum and a “Sedgwick Rafter” counting chamber (x10P>0.05) was observed on populations of Fibrobacter succinogenes, Megaesphaera elsdenii, Streptococcus bovis and Entodimium on both adaptation and finishing periods. No treatment effect was observed (P=0.69) on Diplodinium population in the adaptation period, however, cattle previously restricted or receiving concentrate increased Diplodinium numbers during finishing period (Control: 13.2P<0.01). Cattle receiving concentrate prior to adaptation period had decreased numbers of Dasytricha in the adaptation period (Control: 1.65P<0.01), however, those numbers increased during finishing period(Control: 0.01P<0.01) when compared to cattle on control group. Nutritional restriction or consumption of concentrate prior to adaptation period affected only rumen protozoa populations. Key Words: