Effects of Two Different Straw Pellets on Yak Growth Performance and Ruminal Microbiota during Cold Season

Abstract

The Tianzhu white yaks (Bos grunniens) live on the Qinghai–Tibet Plateau. During winter, a lack of resources and low nutritional levels seriously affect their growth performance. In this study, we aimed to explore the effect of supplementation straw pellets on the growth performance and ruminal microbiota of yaks. Overall, at 6 (6M, n = 24), 18 (18M, n = 26), 30 (30M, n = 20), 42 (42M, n = 24), and 54 (54M, n = 22) month old Tianzhu white yaks were selected (total n = 116) and divided into the mixed straw + grazing (MSG), corn straw + grazing (CSG), and the grazing control (G) groups according to age and gender. Their growth performance was measured as per different dietary treatments. The rumen microbial community structure and levels of VFAs were analyzed from the 6M, 30M, and 54M male yaks from each group. The supplementary diets led to an increase in the ADG, which was the highest in the MSG group. The MSG group exhibited the highest level of acetate and total VFAs (TVFAs) among the three groups (p < 0.05). In addition, the 16S rRNA sequencing results proved that the microbial composition was dominated by the members of Firmicutes and Bacteroidetes. Christensenellaceae R-7 group was significantly abundant in the CSG and MSG groups compared to the G group (p < 0.05). Principal coordinate analysis (PCoA) revealed that the bacterial community structure of rumen in the MSG and CSG groups was considerably different from that in the G group; 6M samples exhibited different rumen microbial diversity compared with the other samples. Correlation analysis revealed that Christensenellaceae_R-7_group was positively correlated with the levels of acetate, TVFAs, and ADG. These results demonstrated that mixed straw pellets improved the growth performance of yaks, increased the abundance of Christensenellaceae R-7_group involved in cellulose degradation in the rumen, and produced large amounts of VFAs, which were absorbed by yaks, thus increasing their ADG. This study provides new insights into the effects of straw pellet supplementation on the changes in the rumen microbiota and growth performance of yaks.

Undernutrition Disrupts Cecal Microbiota and Epithelium Interactions, Epithelial Metabolism, and Immune Responses in a Pregnant Sheep Model

“…The molar proportion of acetate decreased in spite of the increased concentration of acetate, which was caused by the relatively lower increasing rate of acetate concentration compared to total VFA concentration. Essentially, the changed molar proportions of VFAs resulted from the altered microbial community structures ( 29 ). In previous studies, Clostridia vadinBB60 group_norank is negatively correlated with butyrate proportion ( 6 ); Oscillospiraceae _uncultured can produce butyrate from their fermentable carbon source ( 10 , 30 ); Peptococcaceae is positively correlated with butyrate concentration ( 31 ); Peptococcaceae _uncultured is positively correlated with valerate proportion ( 32 ); Ruminococcus is essential for carbohydrate-active enzymes that can produce acetate from maltose oligosaccharides and transient glucose produced during starch degradation ( 33 ); and Rikenellaceae dgA-11 gut group is positively correlated with acetate concentration ( 34 ) and Rikenellaceae RC9 gut group is positively correlated with acetate proportion ( 35 ).…”

From the perspective of rumen microbiome and host metabolome, revealing the effects of feeding strategies on Jersey Cows on the Tibetan Plateau

“…The frozen samples were thawed at 4 °C and centrifuged at 3000 × g at 4 °C for 10 min. The VFAs were measured by using gas chromatography (Agilent 6890N, Santa Clara, CA, USA) with a chromatographic column (HP 19091N-213), according to the method of Wang et al (2023) . The NH 3 -N concentration of rumen fluid was determined colorimetrically (Spectrophotometer U-2900; Hitachi, Tokyo, Japan) by following the method ( Weatherburn, 1967 ).…”

The Stool Microbiome in African Ruminants: A Comparative Metataxonomic Study Suggests Potential for Biogas Production

“…Although Gazella showed the highest abundance of the Christensenellaceae_R-7_group, reaching 9.62%, and Bongo stood out with the highest abundance of the Rikenellaceae_RC9_gut_group, reaching 10.06%, all of the samples revealed a relatively high abundance regarding these two groups when compared with results obtained in other studies on rumen samples. According to Wang (2023) and Liu (2022), who compared the rumen microbial communities between Yaks and Qaidam cattle, the relative abundance of the Rikenellaceae_RC9_gut_group and the Christensenellaceae_R-7_group in Yaks was revealed to be higher, reaching 10.6% and 8.0%, respectively [39]. On the other hand, Dong (2023) found a lower abundance of the Rikenellaceae_RC9_gut_group (7.06%) and the Christensenellaceae_R-7_group (5.27%) when studying cow fecal flora [40].…”