Relationship between jejunum ATPase activity and antioxidant function on the growth performance, feed conversion efficiency, and jejunum microbiota in Hu sheep (Ovis aries).

BACKGROUND: ATPase activity and the antioxidant function of intestinal tissue can reflect intestinal cell metabolic activity and oxidative damage, which might be related to intestinal function. However, the specific influence of intestinal ATPase activity and antioxidant function on growth performance, feed conversion efficiency, and the intestinal microbiota in sheep remains unclear. RESULTS: This study analyzed the correlation between ATPase activity and antioxidant function in the jejunum of 92 Hu sheep and their growth performance and feed conversion efficiency. Additionally, individuals with the highest (H group) and lowest (L group) jejunum MDA content and Na+ K+-ATPase activity were further screened, and the effects of jejunum ATPase activity and MDA content on the morphology and microbial community of sheep intestines were analyzed. There was a significant correlation between jejunum ATPase and SOD activity and the initial weight of Hu sheep (P < 0.01). The H-MDA group exhibited significantly higher average daily gain (ADG) from 0 to 80 days old and higher body weight (BW) after 80 days. ATPase and SOD activities, and MDA levels correlated significantly and positively with heart weight. The jejunum crypt depth and circular muscle thickness in the H-ATP group were significantly higher than in the L-ATP group, and the villus length, crypt depth, and longitudinal muscle thickness in the H-MDA group were significantly higher than in the L-MDA group (P < 0.01). High ATPase activity and MDA content significantly reduced the jejunum microbial diversity, as indicated by the Chao1 index and observed species, and affected the relative abundance of specific taxa. Among species, the relative abundance of Olsenella umbonata was significantly higher in the H-MDA group than in the L-MDA group (P < 0.05), while Methanobrevibacter ruminantium abundance was significantly lower than in the L-MDA group (P < 0.05). In vitro culture experiments confirmed that MDA promoted the proliferation of Olsenella umbonata. Thus, ATPase and SOD activities in the jejunum tissues of Hu sheep are predominantly influenced by congenital factors, and lambs with higher birth weights exhibit lower Na+ K+-ATPase, Ca2+ Mg2+-ATPase, and SOD activities. CONCLUSIONS: The ATPase activity and antioxidant performance of intestinal tissue are closely related to growth performance, heart development, and intestinal tissue morphology. High ATPase activity and MDA content reduced the microbial diversity of intestinal tissue and affect the relative abundance of specific taxa, representing a potential interaction between the host and its intestinal microbiota.

PDE9A polymorphism and association analysis with growth performance and gastrointestinal weight of Hu sheep.

Phosphodiesterase 9A (PDE9A) plays a crucial role in activating the cGMP-dependent signaling pathway and may have important effects on the growth and development of the gastrointestinal tract in Hu sheep. In this study, we analyzed the single nucleotide polymorphisms of PDE9A in 988 Hu sheep and their correlation with growth performance, feed efficiency, and gastrointestinal development. Additionally, we examined the expression level of different PDE9A genotypes in the gastrointestinal tract of Hu sheep by using fluorescence quantitative PCR. The results revealed a moderate level of polymorphism (0.25 < PIC < 0.50) at the g.286248617 T > C mutation site located in the first intron of PDE9A in Hu sheep, with three genotypes: CC, CT, and TT. The weights of the omasum, colon, and cecum were significantly greater in the CC genotype than in the TT genotype (P < 0.05), and the expression level of PDE9A in the tissues of the rumen, ileum, cecum, and colon was notably lower in the CC genotype individuals (P < 0.05). These findings suggest that the polymorphism of PDE9A affects the weight of the stomach, colon, and cecum in Hu sheep through expression regulation. Overall, the results of this study suggest that the g.286248617 T > C mutation site in the first intron of PDE9A can serve as a potential molecular marker for breeding practices related to the gastrointestinal weight of Hu sheep.

Transcriptome Analysis to Elucidate the Effects of Milk Replacer Feeding Level on Intestinal Function and Development of Early Lambs.

Although early feeding strategies influence intestinal development, the effects of milk replacer (MR) feeding level on intestinal structure and functional development and underlying regulatory mechanisms remain unclear. In this study, 14 male Hu lambs were fed MR at 2% or 4% of their average body weight and weaned at 35 days of age. The MR was produced by the Institute of Feed Research of the Chinese Academy of Agricultural Sciences, and it contains 96.91% dry matter, 23.22% protein, and 13.20% fat. Jejunal tissues were assessed by RNA-seq for differences in the gene expression of lambs at 49 days of age; regulatory pathways and mechanisms of the effects of early nutrition on intestinal function and development were analyzed, along with growth performance, feed intake, jejunal histomorphology, and digestive enzyme activities. Increasing MR- feeding levels increased dry matter intake and daily gain before weaning, as well as lactase, amylase, lipase, trypsin, and chymotrypsin activities and intestinal villus length and muscular thickness. Overall, 1179 differentially expressed genes were identified, which were enriched in nutrient metabolism, coagulation cascades, and other pathways. Further, intensive MR feeding affected insulin sensitivity to reduce excessive glucose interception by intestinal tissues to ensure adequate absorbed glucose release into the portal circulation and promoted lipid and protein degradation in intestinal tissues to meet the energy demand of intestinal cells by regulating AHSG, IGFBP1, MGAT2, ITIH, and CYP2E1 expression.

Study on Low-Velocity Impact Damage and Residual Strength of Reinforced Composite Skin Structure.

In order to better understand the damage tolerance of reinforced composite plates, the impact damage of the reinforced composite plates was investigated under low-velocity impact test. The experimental results show that the impact of different positions and energies causes different degrees of damage to the specimens, including but not limited to ply fracture, internal delamination of the skin, and debonding of the stiffeners and skin. After impacting, the specimens were tested in an axial compression. The results show that the ultimate bearing capacity of the specimen is also affected by different forms of impact. The impact point has the greatest influence on the specimen while it locates at the intersection of longitudinal and transverse bars. Compared with the intact specimen, the ultimate load carrying capacity was reduced by 16.83% and 44.02%, while the specimen impacted by 15 J and 30 J, respectively. The compression failure mode of the damaged specimen is mainly the breakage of the stiffeners and the delamination of the skin.