Thyme essential oil for sheep: effect on rumen fermentation, nutrient digestibility, nitrogen metabolism, and growth

A.D.B Ribeiro,A.A Miszura,J.P.R Barroso,D.M Polizel,M.V.C Ferraz Junior,L.G.M Gobato,I Susin,A.V Pires

doi:10.1590/1678-4162-10792

Abstract

ABSTRACT Two experiments were conducted to evaluate the effect of thyme (Thymus vulgaris) essential oil (EO) doses on rumen fermentation, nutrient digestibility, and nitrogen metabolism, as well as performance and coccidia oocyst discharge. In experiment I, 20 rumen-cannulated wethers received the experimental diets containing 80% dry matter (DM) of haylage and 20% DM of concentrate. Treatments were 25mg of monensin/kg DM or doses of 1.25, 2.50, or 3.75g of thyme EO/kg DM. In experiment II, 50 ewe lambs received the same diets from experiment I, including a diet without feed additives. Wethers fed with diets containing 1.25g/kg DM of thyme EO had higher molar proportion of propionate (P= 0.03) and butyrate (P< 0.01), and lower (P= 0.04) acetate to propionate ratio than other treatments. Adding thyme EO to diets increased (P= 0.02) nitrogen retention compared to monensin. The performance of ewe lambs was not affected (P≥ 0.05) by treatments. However, lambs fed monensin had a lower (P= 0.04) number of coccidia oocyst discharge than others. Adding 1.25g/kg DM of thyme EO in high-forage diet improved ruminal fermentation. Thyme EO enhanced nitrogen metabolism, however, it did not improve performance.

Highlights

Ionophores are one of the most used feed additives for ruminants (Oliveira and Millen, 2014), the use of monensin as a growth promoter was banned in the European Union (OJEU, 2003), it is necessary to find substitutes from monensin, if it is prohibited in Brazil
This study aimed to determine the effects of thyme essential oils (EO) on rumen fermentation, nutrient digestibility, performance and coccidia oocyst discharge of the sheep fed with highforage diets
Wethers fed diets containing 1.25 of EO/kg dry matter (DM) had higher (P> 0.01) molar proportion of butyrate compared to other treatments on the 7th and 28th days (Figure 1B)

Summary

Introduction

Ionophores are one of the most used feed additives for ruminants (Oliveira and Millen, 2014), the use of monensin as a growth promoter was banned in the European Union (OJEU, 2003), it is necessary to find substitutes from monensin, if it is prohibited in Brazil. Thyme EO was able to change the rumen microbial population (Cristani et al, 2007; Ultee et al, 2002; Juven et al, 1994), as well as decrease molar proportion of acetate and acetate to propionate (Ac:Prop) ratio, and increase the molar proportion of propionate in cattle fed high-concentrate diets (Vakili et al, 2013). The thymol is the main compound found in EO extracted from thymus plant (Thymus vulgaris; Table 1; Juven et al, 1994), which is able to inhibit gram-positive and gram-negative bacteria by decreasing enzyme activity and modifying membrane integrity (Juven et al, 1994). This study aimed to determine the effects of thyme EO on rumen fermentation, nutrient digestibility, performance and coccidia oocyst discharge of the sheep fed with highforage diets

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Results

Conclusion