Isolation, Identification, and Function of Rhodotorula mucilaginosa TZR2014 and Its Effects on the Growth and Health of Weaned Piglets

Abstract

A red yeast isolated from orange and grape soil and identified by the 26S rDNA sequence analysis revealed that it was Rhodotorula mucilaginosa and named TZR₂₀₁₄. Its biomass and carotenoid production reached a maximum when using the fermentation medium with pH 6.0, containing 5% glucose, 1% peptone, and 1.5% yeast powder. TZR₂₀₁₄ was resistant to 55°C for 15 min, 0.2% pig bile salts for 4 h, and artificial gastric and intestinal fluids. A total of thirty 28-day weaned pigs were divided into three groups, and the piglets were fed a basal diet (CON), a basal diet and orally administered 1 ml 1.0 × 10¹⁰ CFU/ml Candida utilis DSM 2361 three times (C. utilis), or a basal diet and orally administered 1 ml 1.0 × 10¹⁰ CFU/mL TZR₂₀₁₄ three times daily (R. mucilaginosa) for 4 weeks. Compared with the piglets in the CON group, those in the C. utilis or R. mucilaginosa group reported an increased average daily weight gain and average daily feed intake (P < 0.05) and a decreased feed/gain (P < 0.05). The diarrhea rate of piglets in the R. mucilaginosa group was lower than that in the CON and C. utilis groups (P < 0.05). Compared with that in the CON and C. utilis groups, the R. mucilaginosa group reported an increased ileum villus height (P < 0.05), serum concentration of total antioxidant content, total superoxide dismutase, and glutathione peroxidase and pepsin and lipase activities in the intestinal content, while it reported a decreased serum concentration of malondialdehyde and pH of the intestinal tract (P < 0.05). The relative abundances of Proteobacteria and Megasphaera of caecum in the R. mucilaginosa group were lower than those in the CON and C. utilis groups (P < 0.05). The relative abundances of Prevotella, Ruminococcaceae, Succinivibrio, Rikenellaceae RC9 gut group, and Roseburia of caecum in the R. mucilaginosa group were higher than those in the CON and C. utilis groups (P < 0.05). R. mucilaginosa TZR₂₀₁₄ can produce carotenoids and adapts to the animal's gastrointestinal environment. Oral R. mucilaginosa TZR₂₀₁₄ improved growth performance, enhanced antioxidant capacity, strengthened gastrointestinal digestion, and maintained the intestinal microbiological balance of piglets.

Keywords: Rhodotorula mucilaginosa TZR2014; antioxidant capacity; intestinal health; isolation and identification; weaned piglets.

Figure 1

The phylogenetic tree of Rhodotorula mucilaginosa TZR₂₀₁₄ (A), the visual colony morphology (B), and the cell morphology of Rhodotorula mucilaginosa TZR₂₀₁₄ (C).

Figure 2

The effects of temperature (A), pig bile salts (B), artificial gastric juice (C), and artificial intestinal fluid (D) on the growth of R. mucilaginosa TZR₂₀₁₄.

Figure 3

Effects of C. utilis DSM 2361 and R. mucilaginosa on ileum morphology by magnification 40 × (A) and 400 × (B) in weaned piglets. CON, piglets were fed a corn-and a soybean-based basal diet; C. utilis, piglets were fed a soybean-based basal diet and orally administrated 1 ml 1.0 × 10¹⁰ CFU/ml C. utilis DSM 2361 three times; R. mucilaginosa, piglets were fed a soybean-based basal diet and daily orally administrated 1 ml 1.0 × 10¹⁰ CFU/ml R. mucilaginosa TZR₂₀₁₄ three times daily.