This work aimed to investigate how two different types of forage (saline and alkaline) impact the meat quality and muscle metabolism of Tibetan sheep. An integrative multi-omics analysis of meat quality and different metabolites was performed using untargeted and targeted metabolomics approaches. The research results indicated that GG grass (saline and alkaline forage) possessed superior characteristics in terms of apparent quality and secondary metabolite content compared with HG grass (Non saline alkali forage), regardless of the targeted metabolites or non-targeted ones. Simultaneously, under stress conditions, the carbohydrates-rich salt-alkali grass play a significant role in slowing down the decline in pH, increasing the unsaturated fatty acid content and reducing the thawing loss in Tibetan sheep. This study provides an understanding of the impact of different salt-alkali grass on the quality of Tibetan sheep meat, while providing a scientific basis for the future development of salt-alkali livestock industry.
Silent information regulator 1 and 2 (SIRT1, 2) were NAD+-dependent histone or non-histone deacetylase, which emerged as key metabolic sensors in several tissues of mammals. In the present study, the search for polymorphisms within the ovine SIRT1 and SIRT2 loci as well as association analyses between SNPs and growth-related traits were performed in Tibetan sheep. To determine the expression pattern of SIRT1 and SIRT2 genes in Tibetan sheep, the quantitative real-time polymerase chain reaction (qPCR) analysis revealed that those two genes were widely expressed in diverse tissues. Expression of SIRT1 was less in abomasum of lamb, whereas it was greater in duodenum within adult stage. In the case of SIRT2, the greatest expression was observed in reticulum (lamb) and in muscle (adult), whereas the least expression was in liver for lamb and in kidney for adult animals. The association analysis demonstrated that g.3148 C > T polymorphism of SIRT1 affected heart girth (p = 0.002). The g.8074 T > A SNP of SIRT2 had a significant correlation with body weight (p = 0.011) and body length (p = 0.008). These findings suggested that the SIRT1 and SIRT2 polymorphism was involved in growth-related traits in Tibetan sheep, which may be considered to be genetic markers for improving the growth traits of Tibetan sheep.
The present study was to investigate the association of polymorphisms in exon-9 of the bone morphogenetic protein receptor-1B (BMPR-1B) gene (C864T) with litter size in 240 Dorset, 232 Mongolian, and 124 Small Tail Han ewes.Blood samples were collected from 596 ewes and genomic DNA was extracted using the phenol: chloroform extraction method. The 304-bp amplified polymerase chain reaction product was analyzed for polymorphism by single-strand conformation polymorphism method. The genotypic frequency and allele frequency of BMPR-1B gene exon-9 were computed after sequence alignment. The χ2 independence test was used to analyze the association of genotypic frequency and litter size traits with in each ewe breed, where the phenotype was directly treated as category.The results indicated two different banding patterns AA and AB for this fragment, with the most frequent genotype and allele of AA and A. Calculated Chi-square test for BMPR-1B gene exon-9 was found to be more than that of p value at the 5% level of significance, indicating that the population under study was in Hardy-Weinberg equilibrium for all ewes. The χ2 independence test analyses indicated litter size differences between genotypes was not the same for each breed. The 304-bp nucleotide sequence was subjected to BLAST analysis, and the C864T mutation significantly affected litter size in singletons, twins and multiples. The heterozygosity in exon-9 of BMPR-1B gene could increase litter size for all the studied ewes.Consequently, it appears that the polymorphism BMPR-1B gene exon-9 detected in this study may have potential use in marker assisted selection for litter size in Dorset, Mongolian, and Small Tail Han ewes.
Abstract Background: The rumen is a balanced ecosystem harboring a variety of microorganisms and plays an important role in the digestion and absorption of nutrients for ruminant. However, there are few studies on the effects of dietary crude protein on development and function in rumen of Tibetan sheep. The objective of this study was to evaluate the effects of dietary crude protein (CP) on the antioxidant activity, immunocompetence and the structural properties in the rumen of Tibetan sheep. Sixty two-month-old rams with an average weight of 15.40±0.81 Kg were randomly assigned to low-protein diet (10.20% of dry matter, L group) and high-protein diet (11.58% of dry matter, H group). The experiment was conducted over 97 d, including 7 d of adaption to the diets. Results: Hematoxylin & eosin (H&E) results showed that high-protein diet increased papilla length, papilla width and muscular layer in rumen ( P < 0.05). Compared with L group, supplementation with 11.58% crude protein increased the activities of T-AOC and SOD significantly ( P < 0.05). A total of 612 significant differentially expressed genes (158 up-regulated and 456 down-regulated) were found in response to high-protein diet. Pathways and genes related to fatty acid biosynthesis, nutrition metabolism and muscle development were verified by real-time quantitative polymerase chain reaction. Conclusions: In conclusion, 11.58% crude protein diet had superior papillary development and antioxidant activity of Tibetan sheep, likely through modulating the expression of functional genes.
Introduction Ischemia, resulting from reduced blood supply due to arterial constriction or blockages, leads to oxygen and nutrient deprivation, impacting various body systems and contributing to numerous diseases. Despite extensive research on ischemia, molecular studies with spatial and temporal specificity are limited. Our study utilized single-cell genomics to investigate hypoxia-induced changes in the mouse brain at 30 and 60 minutes of exposure, aiming to map cellular trajectories, ontologies, and expression patterns in a cell-specific manner. Material and methods We developed a mouse model of hypoxia using the thread-plug method. Experimental groups were exposed to hypoxia for 30 minutes (T_30) and 60 minutes (T_60), with a sham surgery group as control. After excising the cerebral cortex, we performed nuclear isolation and library construction for spatio-temporal analysis of cortical cells. Data analysis included differential gene expression, trajectory analysis, examination of gene regulatory networks, and hallmark analysis. Results Single-cell genomics analysis revealed 12 distinct cell populations with different transcriptomic profiles. Spatio-temporal distinctions in cell signaling were observed, showing a switch from Ras GTPase signaling to calmodulin and calcium-dependent signaling between the two hypoxia levels. In the T_30 group, distal axons and growth cones were transcriptionally active, while in the T_60 group, cell edges and post-synaptic areas were more active. The synaptic vesicle cycle was implicated in transcriptional changes across the T_30 and T_60 groups. Conclusions Our single-cell genomics study provides new insights into cellular dynamics during hypoxia. The identified cell populations and molecular pathways highlight potential targets for further research and the development of targeted therapies for ischemia.
Introduction The objective of this study was to evaluate the effects of the dietary lysine (Lys)/ methionine (Met) ratio in a low-protein diet on short-chain fatty acid (SCFA) profiles, villus morphology, antioxidant capacity, and immune status of the jejunum in Tibetan sheep. Methods A total of 90 weaned Tibetan sheep, each 2 months old with an initial weight of 15.37 ± 0.92 kg, were randomly divided into three treatment groups. These groups were supplemented with different Lys/Met ratios of 3 [low protein-high methionine (LP-H)], 2 [low protein-medium methionine (LP-M)], and 1 [low protein-low methionine (LP-L)] in the basal diet (10% crude protein). The feeding trial lasted 100 days, including a 10-day acclimation period and a 90-day experimental period. Results The hematoxylin–eosin (H&E) sections showed that the LP-L group had a significantly increased villus height compared to the LP-M and LP-H groups ( p < 0.05). In addition, the LP-L group showed higher levels of Superoxide dismutase (SOD) activity and Total Antioxidant Capacity (T-AOC) concentrations ( p < 0.05). A lower concentration of Interleukin-1 beta (IL-1β) was observed in the LP-H group ( p < 0.05). The activities of α-amylase, chymotrypsin, and lipase were higher in the LP-L group compared to the LP-H group ( p < 0.05). Bacterial sequencing showed that both Chao1 and ACE richness were significantly increased in the LP-L group ( p < 0.05), suggesting that the species richness in the jejunum is connected to the ratio of dietary Lys/Met. Furthermore, lowering the dietary Lys/ Met ratio significantly increased the abundance of Romboutsia , the Ruminococcus gauvreauii group, the Lachnospiraceae NK3A20 group, Ruminococcus 2 , and the Christensenellaceae R-7 group ( p < 0.05) while decreasing the abundance of Methanobrevibacter ( p < 0.05). Several differential metabolites, including beta-alanine, pantothenate, pantothenic acid, phosphoenolpyruvate, cysteine, adenosine 5′-diphosphate, isodeoxycholic acid, glutamate conjugated cholic acid, and 3-dehydrocholic acid, were significantly increased in the LP-L group ( p < 0.05). The functional analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations indicated that these metabolites were mainly involved in pantothenate and CoA biosynthesis, ferroptosis, and the tricarboxylic acid cycle. Several genes related to barrier function, such as Occludin and Muc- 2, were upregulated in the LP-L group ( p < 0.05), while IL-6 and TNF-α were downregulated ( p < 0.05). Discussion Collectively, our results suggest that the dietary Met/ Lys ratio could affect the jejunal SCFA concentration by modulating the microbial community and regulating metabolism, thereby contributing to jejunal barrier function. Our findings provide a theoretical basis for the application of Lys/Met diet supplementation in the nutritional management of Tibetan sheep, particularly when reducing the dietary crude protein (CP) level.
This paper presented the results on the study of insulin receptor substrate 1 (IRS1) polymorphisms in Chinese black Tibetan sheep. Via DNA direct sequencing, four variations within 3' untranslated region (UTR) of IRS1, including g.9382T > G, g.9569T > G, g.9572C > T and g.9695A > C were detected in the black Tibetan sheep population. Based on the χ2 test, those four loci deviated from Hardy-Weinberg equilibrium (p < 0.05). In g.9569T > G locus, genotype of GG possessed advantage on body weight (p < 0.05). In g.9572C > T locus, individuals with genotype of TT homozygous mutation decreased significantly on body weight, withers height, body length and chest circumference (p < 0.05 or p < 0.01). In g.9695A > C locus, the body weight and chest circumference were also higher in AA carriers than in CC carriers (p < 0.05). Our results provided evidence that polymorphisms in IRS1 were associated with growth efficiency traits by quantitative genetic analysis, and may be used for marker-assisted selection in Chinese indigenous sheep.
Abstract Xylanase, an exogenous enzyme that plays an essential role in energy metabolism by hydrolysing xylan into xylose, has been shown to positively influence nutrient digestion and utilisation in ruminants. The objective of this study was to evaluate the effects of xylanase supplementation on the back‐fat thickness, fatty acid profiles, antioxidant capacity, and differentially expressed genes (DEGs) in the subcutaneous fat of Tibetan sheep. Sixty three‐month‐old rams with an average weight of 19.35 ± 2.18 kg were randomly assigned to control (no enzyme added, WH group) and xylanase (0.2% of diet on a dry matter basis, WE group) treatments. The experiment was conducted over 97 d, including 7 d of adaption to the diets. The results showed that xylanase supplementation in the diet increased adipocyte volume of subcutaneous fat ( p < 0.05), shown by hematoxylin and eosin (H&E) staining. Gas chromatography showed greater concentrations of C14:0 and C16:0 in the subcutaneous fat of controls compared with the enzyme‐treated group ( p < 0.05), while opposite trend was seen for the absolute contents of C18:1n9t, C20:1, C18:2n6c, C18:3, and C18:3n3 ( p < 0.05). Compared with controls, supplementation with xylanase increased the activity of T‐AOC significantly ( p < 0.05). Transcriptomic analysis showed the presence of 1630 DEGs between the two groups, of which 1023 were up‐regulated and 607 were down‐regulated, with enrichment in 4833 Gene Ontology terms, and significant enrichment in 31 terms ( p < 0.05). The common DEGs were enriched in 295 pathways and significantly enriched in 26 pathways. Additionally, the expression of lipid‐related genes, including fatty acid synthase, superoxide dismutase, fatty acid binding protein 5, carnitine palmytoyltransferase 1 A, and peroxisome proliferator‐activated receptor A were verified via quantitative reverse‐transcription polymerase chain reaction. In conclusion, dietary xylanase supplementation was found to reduce subcutaneous fat deposition in Tibetan sheep, likely through modulating the expression of lipid‐related genes.
The objectives of this study were to identify single nucleotide polymorphisms (SNPs) in the growth hormone-releasing hormone (GHRH) gene and to evaluate their associations with growth traits in two main Tibetan sheep breeds.Through sequencing technology, four SNPs were identified in the 5'UTR region of GHRH gene.Both g.794A>C and g.1497C>A exhibited significant influence on the growth-related traits in Tibetan sheep (P<0.05 or P<0.01).Hence, the biochemical and physiological functions, together with the results obtained in our investigation, suggest that the GHRH gene could serve as genetic marker for growth in Tibetan sheep breeding.
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