Nutritional Interventions Improved Rumen Functions and Promoted Compensatory Growth of Growth-Retarded Yaks as Revealed by Integrated Transcripts and Microbiome Analyses

Abstract

Growth retardation reduces the incomes of livestock farming. However, effective nutritional interventions to promote compensatory growth and the mechanisms involving digestive tract microbiomes and transcripts have yet to be elucidated. In this study, Qinghai plateau yaks, which frequently suffer from growth retardation due to malnutrition, were used as an experimental model. Young growth-retarded yaks were pastured (GRP), fed basal ration (GRB), fed basal ration addition cysteamine hydrochloride (CSH; GRBC) or active dry yeast (ADY; GRBY). Another group of growth normal yak was pastured as a positive control (GNP). After 60-day nutritional interventions, the results showed that the average daily gain (ADG) of GRB was similar to the level of GNP, and the growth rates of GRBC and GRBY were significantly higher than the level of GNP ( P < 0.05). Basal rations addition of CSH or ADY either improved the serum biochemical indexes, decreased serum LPS concentration, facilitated ruminal epithelium development and volatile fatty acids (VFA) fermentation of growth-retarded yaks. Comparative transcriptome in rumen epithelium between growth-retarded and normal yaks identified the differentially expressed genes mainly enriched in immune system, digestive system, extracellular matrix and cell adhesion pathways. CSH addition and ADY addition in basal rations upregulated ruminal VFA absorption ( SLC26A3, PAT1, MCT1 ) and cell junction ( CLDN1, CDH1, OCLN ) gene expression, and downregulated complement system ( C2, C7 ) gene expression in the growth-retarded yaks. 16S rDNA results showed that CSH addition and ADY addition in basal rations increased the rumen beneficial bacterial populations ( Prevotella_1, Butyrivibrio_2, Fibrobacter ) of growth-retarded yaks. The correlation analysis identified that ruminal VFAs and beneficial bacteria abundance were significantly positively correlated with cell junction and VFA absorption gene expressions and negatively correlated with complement system gene expressions on the ruminal epithelium. Therefore, CSH addition and ADY addition in basal rations promoted rumen health and body growth of growth-retarded yaks, of which basal ration addition of ADY had the optimal growth-promoting effects. These results suggested that improving nutrition and probiotics addition is a more effective method to improve growth retardation caused by gastrointestinal function deficiencies.

Bacterial communities in the solid, liquid, dorsal, and ventral epithelium fractions of yak (Bos grunniens) rumen

“…We also found that Rikenellaceae RC9 and Prevotella were abundant genera in all four fractions, in accordance with previous findings regarding ruminants generally (Henderson et al, ) and yaks (Hu et al, ; Xue et al, ; Zhang et al, ). Rikenellaceae RC9 can reportedly degrade structural carbohydrates and starch in the rumen of cows (Asma et al, ), while Prevotella spp.…”

“…We also found that members of the phyla Bacteroidetes and Firmicutes were the dominant bacteria in the solid, liquid, and ventral epithelium fractions of yak rumen, in accordance with previous findings in ruminants generally (Henderson et al, ) and yaks specifically (Hu et al, ; Xue et al, ; Zhang et al, ; Zhou, Zhong, et al, ; Zhou, Fang, et al, ). These results indicate that the two phyla have adapted to wide ranges of gastrointestinal tract environments and play important roles in rumen ecology.…”

“…These results indicate that the two phyla have adapted to wide ranges of gastrointestinal tract environments and play important roles in rumen ecology. However, Epsilonbacteraeota was the most abundant bacterial phylum in the yak dorsal epithelium fraction, which has not been recorded in previous studies (An, Dong, & Dong, ; Guo et al, ; Hu et al, ; Xue et al, ; Zhang et al, ; Zhou, Zhong, et al, ; Zhou, Fang, et al, ). The comparative genomic analysis revealed that the host‐associated Epsilonbacteraeota lacked genes involved in carbon fixation, but possessed genes involved in osmoprotection, and transport of heme, lipopolysaccharide, and capsular polysaccharides (Waite et al, ), in accordance with presumed requirements for their epithelium‐associated lifestyle.…”

Interactions Between Rumen Microbes, VFAs, and Host Genes Regulate Nutrient Absorption and Epithelial Barrier Function During Cold Season Nutritional Stress in Tibetan Sheep

“…Further analysis using PCoA and Anosim showed that there was a significant difference between the cold and warm seasons, and the difference between the seasonal groups was significantly greater than that within the groups (P < 0.05). This may be due to the lack of food in the cold season, leading to a large difference in the acquisition of food resources (Sun et al, 2016), as seen in previous studies (Zeng et al, 2017;Zhou et al, 2017;Xue et al, 2018;Hu et al, 2019).…”

The Study of the Response of Fat Metabolism to Long-Term Energy Stress Based on Serum, Fatty Acid and Transcriptome Profiles in Yaks

“…As a classic grazing livestock, the growth of yaks is directly affected by the natural environment. Because of the high altitude (more than 4000 m) of the Tibetan Plateau, there is only a cold season and a warm season [ 4 ]. The growth of animals is affected by the balance between the supply of food and the cost of survival each day [ 5 ].…”