Postprandial changes in particle associated ruminal bacteria in sheep fed ammoniated rice straw

doi:10.1016/S0377-8401(02)00213-4

Animal Feed Science and Technology

Volume 102, Issues 1–4, 16 December 2002, Pages 207-215

https://doi.org/10.1016/S0377-8401(02)00213-4 Get rights and content

Abstract

An experiment was conducted to quantify postprandial changes in particle attaching ruminal bacteria in sheep fed untreated (UTS) and ammoniated (ATS) rice straw. Diaminopimelic acid (DAPA) was used as a marker for the calculation of mass of tightly associated bacteria (TAB). ATS feeding decreased large particle proportion, while increased fine particle proportion. Ammoniation of rice straw had a significant effect on mass of non-associated bacteria (NAB), loosely associated bacteria (LAB) and tightly associated bacteria (TAB) with feed particles, showing the higher values in ATS-fed sheep within 2–5 h after feeding. Significantly increased bacterial densities associated with small and fine particles were also observed, indicating that size of particles is an important factor for the attachment of bacteria. The current study suggests that ammoniation accelerates particle size reduction of rice straw in the rumen, stimulating colonization of bacteria onto the smaller particles and overall degradation of rice straw fragments.

Introduction

The microorganisms in the rumen comprise the numerically important particle associated microbial population that includes up to 70% of all rumen bacteria (Forsberg and Lam, 1977). Therefore, studies on the mode of their attachment and the subsequent digestion of the plant are essential to better understanding of fiber degradation and its possible improvement.

Over the last decade many experiments have indicated the beneficial aspects of ammonia treatment of straw. Most of the studies on ammonia treatment of straw have concentrated on intake, digestibility and animal performance (Brown et al., 1987) and a few on microbial aspects (Minato et al., 1989). Bae et al. (1997) reported that cuticular damage and loss are more prevalent in ammonia treated than untreated rice straw, then underlying tissues are devoid of silica with extensive colonization of bacteria. There is evidence that ammoniation of rice straw tended to increase the cellulolytic bacterial count, leading to increase in fiber digestion, acetate and butyrate production in the rumen (Cann et al., 1991). However, there is little quantitative information on diurnal variations in the rumen bacteria associated with feed particles in vivo (Craig et al., 1987), especially relating to particle sizes.

In the present experiment, we studied the effect of ammoniated rice straw feeding on postprandial changes in particle attached ruminal bacteria. Moreover, bacterial density on different size of particles were also determined to clarify mode of bacterial colonization relating to the fiber digestion of rice straw by the ruminants.

Section snippets

Experimental design, animals, diets and sample collection

Rice straw was ammoniated by a gaseous method (3 g NH₃/100 g DM) under environmental condition (average temperature 17 °C), stored for 4 weeks in a sealed bag, and excess ammonia was removed by opening the bag prior to feeding to the animals.

Three adult ruminally cannulated wethers averaging 68 kg in body weight were fed untreated rice straw (UTS) for 6 weeks followed by ammoniated rice straw (ATS) for 6 weeks twice daily at 08:30 and 20:30 h. The wethers were kept individually in spacious pens with

Results

Chemical analysis of the untreated rice straw indicated 61.1% NDF and 36.3% ADF. The responses due to ammoniation resulted in a decrease to 56.6% NDF and an increase to 37.7% ADF. Ammoniation, however, increased total CP content of rice straw almost three-fold (3.9 versus 10.9%) in the present experiment. DM intake for 2 h restriction was 0.89 and 0.92 kg per day for UTS and ATS, respectively.

Ruminal pH was almost always higher for UTS (7.0–7.6) compared to ATS (6.8–7.4) without a significance.

Discussion

Ammoniation causes a higher CP and a lower NDF in general which is in good agreement with the present results. ATS feeding caused a higher NH₃ level (21.7 mg/dl) and lower pH (6.8) without affecting total VFA in the rumen. These all are similar to the preceding results. Accordingly, the prepared ATS is thought to reproduce widely accepted phenomena in ATS feeding. All kinetic parameters of the DM and NDF disappearances in the rumen tended to be higher in ATS (Table 1).

Especially, readily

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These results suggest that reduced mechanical resistance through ammoniation gives a higher fragility of rice straw to promote particle size reduction and exposure of particle sites available for bacterial attachment and growth.
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Short communicationPostprandial changes in particle associated ruminal bacteria in sheep fed ammoniated rice straw

Abstract

Introduction

Section snippets

Experimental design, animals, diets and sample collection

Results

Discussion

Anim. Feed Sci. Technol.

Anim. Feed Sci. Technol.

J. Nutr.

Anim. Feed Sci. Technol.

J. Dairy Sci.

Ammoniation or cane molasses supplementation of low quality forage

J. Anim. Sci.

Use of adenosine 5-triphosphate as an indicator of the microbiota biomass in rumen contents

Appl. Environ. Microbiol.

Short communication
Postprandial changes in particle associated ruminal bacteria in sheep fed ammoniated rice straw