Effect of an energy-deficient diet on populations of ciliate protozoans in bovine rumen

Pierre Castro Soares ,Maria Cláudia Araripe Sucupira ,Clara Satsuki Mori ,Isabel Martinele ,Alexandre Coutinho Antonelli ,Celso Akio Maruta ,Marta D’agosto ,Enrico Lippi Ortolani

doi:10.1590/s0102-09352008000100021

Abstract

Ten young rumen-cannulated crossbred steers were randomly divided into two groups: a control group (C; n=4), which was fed a balanced diet for daily weight gain of 900g; and a pronounced energy-deprived group (PED; n=6), receiving 30% less of the required energy for maintenance. After 140 days of these alimentary regimes, rumen fluid and urine samples were collected for biochemical and functional tests, before feeding and at 1, 3, 6, and 9 hours after feeding. The energy-deprivation diet caused a significant reduction in the number of Entodinium, Eodinium, Isotricha, Dasytricha, Eremoplastron, Eudiplodinium, Metadinium, Charonina, Ostracodinium, and Epidinium protozoa. There was no effect of the time of sampling in both groups on the total number of ciliates in rumen fluid. A higher number of protozoan forms in binary division were recorded in the control group, at the 6th and 9th hours after feeding (P<0.019). There was a high positive correlation between the total count of protozoans in rumen fluid and glucose fermentation, ammonia, and urinary allantoin excretion index; and a negative correlation between the total count of protozoa and metilene blue reduction, and a medium correlation between the total count of protozoa and total volatile fatty acids concentration. The determination of the protozoa populations does not imply in the use of complex and hard-to-execute techniques, although it is time consuming and needs practice. This exam particularly helps in clinical expected diagnosis.

Highlights

Tropical forage plants grow less in the dry season, have lower protein and energy content and higher crude fiber content
The objectives of the present study were to evaluate the effects of feeding time on the ciliate protozoa of the rumen of bovines fed diets deficient or not in energy, and to estimate their correlations with biochemical and functional tests on the ruminal fluid and urine
The steers were randomly allocated in two groups: a control group (C; n=4) and a group with pronounced energy deficient diet (PED; n=6)

Summary

Introduction

Tropical forage plants grow less in the dry season, have lower protein and energy content and higher crude fiber content. Ingestion of dry matter by ruminants decreases significantly in this period of the year, because of the slower growth rate of the forage and its lower digestibility, leading to less energy and protein intake resulting in significant loss of body weight. Rumen ciliate protozoa play diverse and important roles in ruminal metabolism of nutrients (Williams and Coleman, 1992; Hristov et al, 2001) and the feed level has been suggested as one of the factors which influence the ciliate protozoan population in the rumen (Potter and Dehority, 1973; Leng et al, 1981; Franzolin and Dehority, 1996)

Objectives

Methods

Results