Effects of yeast cultures on meat quality, flavor composition and rumen microbiota in lambs

Abstract

Since the banning of antibiotics, the use of feed additives to improve meat quality to satisfy people's pursuit of high quality has become a research hotspot. Yeast culture (YC) is rich in proteins, mannan oligosaccharides, peptides, and yeast cell metabolites, etc., and its use as a feed additive has a positive impact on improving meat quality. So the study aimed to provide a theoretical basis for YC improving mutton flavor and quality by detecting and analyzing the effects of YC on muscle physicochemical properties, amino acids, fatty acids, flavor composition, expression of related genes, and rumen microbiota of lambs. A total of 20 crossbred F1 weaned lambs (Australian white sheep♂ × Hu sheep♀; average 23.38 ± 1.17 kg) were randomly assigned to 2 groups, the control group (CON) and the 1.0% YC supplemented group (YC) (n = 10), and were reared in separate pens. The experiment had a pre-feeding period of 10 d and a treatment period of 60 d. After the experiment, 6 lambs in each group were randomly selected for slaughtering. The results showed that dietary YC supplementation increased rumen total VFA and acetate concentrations (p < 0.05), and muscle carcass fat (GR), a∗ value, intramuscular fat (IMF), lysine (Lys), arginine (Arg), nonessential amino acid (NEAA), oleic acid (C18:1n9c), and eicosanoic acid (C20:1) contents were significantly increased (p < 0.05), while cooking loss and γ-linolenic acid (C18: 3n6) were decreased (p < 0.05). Furthermore, we found that dietary YC improved the types of flavor compounds, and the key flavor substances such as hexanal, nonanal, styrene, benzaldehyde, p-xylene, and 1-octen-3-ol contents were changed (p < 0.05). Additionally, the expression of fat metabolism related genes PPARγ, FASN, and FABP4 were increased. Adding 1% YC to lamb diets increased profits by 47.70 CNY per sheep after 60 d of fattening. All of which indicated that YC could improve meat quality, especially flavor, which may be related to the regulation of the relative abundance of rumen microorganisms Bacteroidota, Prevotella_7, Succiniclasticum and Lachnospiraceae_NK3A20_group.

Keywords: Fatty acids; Flavor substances; Muscle amino acids; Rumen microbiota; Yeast culture.

Graphical abstract

Fig. 1

Numbers (A) and relative contents (B) of volatile flavor compounds in two groups.

Fig. 2

Effects of dietary YC supplementation on the expression of genes related to muscle fat metabolism. All values were expressed as means ± SEM, n = 6. CON = Control group; YC= Yeast culture group. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001.

Fig. 3

Effects of dietary YC supplementation on rumen microbial composition. (A) PCoA analysis; (B) dilution curve analysis; (C) OTU-Venn analysis; (D) Relative abundance at the phylum levels of ruminal microbiota; (E) The relative abundances at the genus levels of ruminal microbiota; (F) Significantly different bacterial taxa identified by the linear discriminant analysis effect size (LEfSe). All values were expressed as means ± SEM, n = 6. CON = Control group; YC= Yeast culture group.

Fig. 4

Correlation analysis. (A) Correlation analysis between key volatile flavor compounds and amino acids. (B) Correlation analysis between key volatile flavor compounds and unsaturated acids. The values represent correlation coefficients. Red represents positive correlation and blue represents negative correlation. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5

Correlation analysis. (A) Correlation analysis between key volatile flavor compounds and fat metabolism related genes. (B) Correlation analysis between key volatile flavor substances and rumen bacteria. The values represent correlation coefficients. Red represents positive correlation and blue represents negative correlation. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 6

Effects of YC on rumen microbiota and muscle fatty acids, amino acids and flavor substances. Arrows indicate the correlation.