Ruminal fermentation, microbial population and lipid metabolism in gastrointestinal nematode-infected lambs fed a diet supplemented with herbal mixtures.

Paulina Szulc,Zora Váradyová,Klaudia Čobanová,Linggawastu Syahrulawal,Adam Cieslak,Malgorzata Szumacher-Strabel,Dominika Mravčáková,Amlan Kumar Patra,Marián Várady,Simon Russell Clegg

doi:10.1371/journal.pone.0231516

Abstract

The aim of this study was to evaluate the effects of medicinal herbal mixtures rich in phenolic, flavonoid and alkaloid compounds on ruminal fermentation and microbial populations, and fatty acid (FA) concentrations and lipid oxidation in tissues of lambs infected with the gastrointestinal nematode (GIN) parasite (Haemonchus contortus). Parallel in vitro and in vivo studies were performed using two different herbal mixtures (Mix1 and Mix2). The in vitro study was conducted in a 2 (infection status; non-infected versus infected) × 3 (diets; control, Mix1 and Mix2) factorial design. In the in vivo study, 24 lambs were equally divided into four treatments: non-infected lambs fed a control diet, infected lambs fed the control diet, infected lambs fed a diet with Mix1 and infected lambs fed a diet with Mix2. Herbal mixtures (100 g dry matter (DM)/d) were added to the basal diets of meadow hay (ad libitum) and a commercial concentrate (500 g DM/d). The experimental period lasted for 70 days. Ruminal fermentation characteristics and methane production were not affected by infection in vivo or in vitro. Both herbal mixture supplementation increased total volatile fatty acid (VFA) concentrations (P < 0.01) and DM digestibility (P < 0.01) in vitro. Archaea population was slightly diminished by both herbal mixtures (P < 0.05), but they did not lower methane production in vitro or in vivo (P > 0.05). Infection of H. contortus or herbal mixtures modulated FA proportion mainly in the liver, especially the long chain FA proportion. Concentrations of thiobarbituric acid reactive substances (TBARS) in serum were significantly higher after 70 days post-infection in the infected lambs. Herbal Mix1 supplementation reduced TBARS concentrations in meat after seven days of storage. In conclusion, supplementing of herbal mixtures to the diets of GIN parasite infected lambs did not affect the basic ruminal fermentation parameters. Herbal mixtures may improve few FA proportions mainly in liver as well as decrease lipid oxidation in meat.

Highlights

Gastrointestinal parasitic infections is one of the major issues impacting the health of livestock animals, especially by the most pathogenic gastrointestinal nematode (GIN) parasite Haemonchus contortus
The gas produced in Control infected (CI) decreased compared to control group (CN) (P = 0.03), but was similar in the infected and non-infected groups supplemented with herbal mixture 1 (Mix1) and herbal mixture 2 (Mix2) (P = 0.02)
Methane production in Mix1 infected (Mix1I) was lower than the Mix 1 non-infected (Mix1N) and Mix 2 infected (Mix2I) when CH4 was expressed as CH4/gas produced and CH4/in vitro dry matter digestibility (IVDMD) (P = 0.03 and P = 0.05, respectively)

Summary

Introduction

Gastrointestinal parasitic infections is one of the major issues impacting the health of livestock animals, especially by the most pathogenic gastrointestinal nematode (GIN) parasite Haemonchus contortus. This GIN sucks abomasum blood and causes anemia, reduces reproductive capacity and animal production, resulting in considerable economic losses [1,2]. PSM that contains phytochemical substances such as flavonoids considers as important bioactive compound as antioxidant and antimicrobial properties in the rumen [9,10] Another bioactive compound is polyphenol known as highly abundant groups of substances found in plants that can be classified based on a simple structure, for instance, phenolic acids and more complex such as tannins [11]. The degree of ruminal fatty acid (FA) saturation affects FA composition in ruminant products such as meat and milk [15,16]

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