Effects of isovalerate on ruminal fermentation, urinary excretion of purine derivatives and digestibility in steers

Abstract

The objective of this study was to evaluate the effects of isovalerate supplementation on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in the total tract of steers. Eight ruminally cannulated Simmental steers were used in a replicated 4 · 4 Latin square experiment. The treatments were: control (without isovalerate), low isovalerate (LIV), medium isovalerate (MIV) and high isovalerate (HIV) dosage of isovalerate at 100, 200 and 300 mg isovalerate per kg dry matter (DM) intake respectively. Diets consisted of corn stover and concentrate (60/40, DM basis). Dry matter intake was approximately 9 kg per day that was 90% of ad libitum intake including 5.4 kg corn stover and 3.6 kg concentrate. Ruminal pH (6.72–6.54) was linearly (p < 0.03) reduced, whereas total volatile fatty acid concentration (64.6–74.7 mmol/l) was linearly (p < 0.01) and quadratically (p < 0.01) increased with increasing isovalerate supplementation. Ratio of acetate to propionate increased linearly (p < 0.01) from 2.78 to 3.39 as isovalerate supplementation increased because of the increase in acetate production and decrease in propionate production. In situ ruminal degradation of amylase-treated neutral detergent fibre (aNDF) of corn stover was improved, but crude protein (CP) degradability of soybean meal decreased with increasing isovalerate supplementation. Urinary excretion of purine derivatives was quadratically (p < 0.01) changed by altering isovalerate supplementation (50.5, 54.3, 58.9 and 55.2 mmol/day for control, LIV, MIV and HIV, respectively). Similarly, digestibilities of organic matter, aNDF and CP in the total tract were linearly and quadratically increased with increasing isovalerate supplementation. The results of this study indicate that supplementation of diet with isovalerate improved ruminal fermentation and feed digestion in beef cattle. It was suggested that the isovalerate stimulated the digestive microorganisms or enzymes in a dose-dependent manner.

Effects of Branched-chain Amino Acids on &lt;italic&gt;In vitro&lt;/italic&gt; Ruminal Fermentation of Wheat Straw

“…In this study, total branched-chain VFA yields linearly increased as the supplemental amount of BCAA was increased. Several studies have shown that ruminal fermentation is stimulated and fiber digestion is enhanced by BCVFA supplementation (Liu et al, 2009), further proving that valine or isoleucine supplementation has a tendency to increase the degradation of wheat straw in the present study.…”

“…Previous studies have shown that BCVFA can improve apparent dry matter digestibility and microbial growth, and enhance microbial functions and enzyme activities in the rumen of sheep (Andries et al, 1990; Moharrery, 2004). Dietary supplementation with BCVFA improves rumen fermentation and enhances digestion of cattle (Liu et al, 2008, 2009). …”

Effects of rumen-protected folic acid on ruminal fermentation, microbial enzyme activity, cellulolytic bacteria and urinary excretion of purine derivatives in growing beef steers

“…The ruminal degradability of feed fibre is closely related to the concentration of ruminal acetate and fibre digestion in the total tract (Liu et al, 2009a;Wang et al, 2009). The quadratic increase in ruminal degradability of NDF of corn silage with increasing PRFA supplementation was in accordance with the increased ruminal enzyme activity, populations of ruminal cellulolytic bacteria, and resulted in the quadratic increased ruminal total VFA and molar ratio of acetate.…”

The fungal community and its interaction with the concentration of short‐chain fatty acids in the caecum and colon of weaned piglets

“…Because BCFAs are generated principally from amino acids, their formation by colonic bacteria provides a useful marker of protein digestion in the large intestine of human (Macfarlane & Macfarlane, ), suggesting that fungi in the hindgut of piglets may probably be highly related to the protein digestion. BCFAs also have been extensively studied in ruminants and proved to be necessary for the growth of ruminal cellulolytic bacteria, such as Ruminococcus albus and Ruminococcus flavefaciens (Liu et al, ; Wang et al, ). In view of that, our results indicate that fungi in the hindgut of the piglets may be associated with the activity of fibre degrading bacteria, which in turn, may be involved in the utilization of complex carbohydrates in the diet.…”