Litter size influences rumen microbiota and fermentation efficiency, thus determining host early growth in goats

IntroductionMultiple litters are accompanied by low birth weight, low survival rates, and growth rates in goats during early life. Regulating rumen microbiota structure can indirectly or directly affect host metabolism and animal growth. However, the relationship between high litter size and rumen microbiome, rumen fermentation, and growth performance in goat kids is unclear.MethodsIn the present study, thirty 6-month-old, female goats were investigated, of which 10 goats were randomly chosen from single, twin and triplet goats respectively, and their birth weight was recorded. From birth, all goats were subjected to the same feed and management practices. Individual weaning and youth body weight were measured, and the rumen fluid samples were collected to characterize the bacterial communities and to determine the ruminal volatile fatty acids (VFA), free amino acids (AA), and free fatty acids (FA) concentration of those young goats.Results and DiscussionCompared with the single and twin goats, triplet goats have lower weaning and youth body weight and average daily gain (ADG). Ruminal propionate, butyrate, and total VFA were decreased in triplet goats. Meanwhile, ruminal AA, such as branched chain amino acids (BCAA), essential amino acids (EAA), unsaturated fatty acids (UFA), and monounsaturated fatty acids (MUFA) were decreased, while saturated fatty acids (SFA) and odd and branched chain fatty acids (OBCFA) were increased in triplet goats. Our results also revealed that litter size significantly affected the rumen bacterial communities, and triplet goats had a lower the Firmicutes: Bacteroidota ratio, the abundance of Firmicutes phylum, Rikenellaceae family, and Rikenellaceae RC9 gut group, and had a higher proportion of Prevotellaceae family, and several genera of Prevotellaceae, such as Prevotella, and unclassified f Prevotellaceae. Furthermore, Spearman’s correlation network analysis showed that the changes in the rumen bacteria were associated with changes in rumen metabolites. In conclusion, this study revealed that high litter size could bring disturbances to the microbial communities and decrease the rumen fermentation efficiency and growth performance, which can be utilized to better understand variation in microbial ecology that will improve growth performance in triplet goats

Feature of Heart Rate Variability and Metabolic Mechanism in Female College Students with Depression

Purpose. To explore the effects of depression on cardiac autonomic nerve function and related metabolic pathways, the heart rate variability (HRV) and urinary differential metabolites were detected on the college students with depression. Methods. 12 female freshmen with depression were filtered by the Beck Depression Inventory (BDI-II) and Self-rating Depression Scale (SDS). By wearing an HRV monitoring system, time domain indexes and frequency domain indexes were measured over 24 hours. Liquid chromatography–mass spectrometry (LC-MS) was used to detect their urinary differential metabolites. Differential metabolites were identified by principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA). The metabolic pathways related to these differential metabolites were analyzed by the MetPA database. Results. Stress time was significantly increased, and recovery time was markedly decreased in the depression group compared with the control group (p<0.001). Standard deviation of the normal-to-normal R interval (SDNN), root mean square of the beat-to-beat differences (RMSSD), high frequency (HF), and low frequency (LF) were decreased significantly (p<0.01). Moreover, 15 differential metabolites (4↑, 11↓) were identified in the depression group. These differential metabolites were involved in the disruption of five metabolic pathways (coenzyme Q biosynthesis, glycine-serine-threonine metabolism, tyrosine metabolism, pyrimidine metabolism, and steroid metabolism). Conclusion. Some autonomic nervous system disruption, high stress, and poor fatigue recovery were confirmed in college students with depression. The metabolic mechanism involved the disruption of coenzyme Q biosynthesis, glycine-serine-threonine metabolism, tyrosine metabolism, pyrimidine metabolism, and steroid metabolism under daily stress

Evaluation of habitat quality and ecological flow in a regulated waterway

Dam control changes the hydraulic environment and hydrological rhythm of rivers; to explore the causes of fish habitat loss and influence of river regulation in such rivers, the downstream curving reaches of Shaying River were cut off. Grass, silver, and bighead carp were selected as the research targets, and the impact of waterway regulation and the effect of gravel mounds on the target fish habitat were studied using numerical simulation. The results show that the original channel's hydraulic environment is similar to the artificial channel, and the target fish spawning habitat is limited, which is an important reason for the shortage of fish resources in the research area. The reconstructed channel can meet the river's navigation demands and improve the channel's flood discharge capacity. The habitat method was used to estimate the minimum and appropriate ecological flows of the target fish at each growth stage in the original and reconstructed rivers. Under the appropriate ecological flow, the weighted usable area (WUA) of juvenile, migratory, and spawning habitats of the target fish in the reconstructed river increased by 168, 24, and 580%, respectively, compared to the original channel, while the WUA of adult fish that preferred a slow-water environment decreased by 62%, effectively improving the target fish's spawning environment. HIGHLIGHTS The habitat distribution of the four major Chinese carps in the whole life cycle was screened and analyzed.; The study shows the complete research process from waterway regulation to biological habitat restoration to ecological flow calculation.; A biological habitat restoration scheme with gravel mounds was adopted, and the navigation and flood discharge capacity of the waterway was not affected.

Study on the Influence of Agricultural Scale Management Mode on Production Efficiency Based on Meta-Analysis

Agricultural scale management is an important means of improving agricultural production efficiency. To answer the controversy over whether different agricultural scale management models can improve production efficiency, this paper obtained 117,627 samples from 68 domestic and foreign literature and used meta-analysis to study the effects of land-scale operation (LSO) and service-scale operation (SSO) on agricultural production efficiency (APE). The moderators that affect the relationship between LSO, SSO, and APE are also examined. The research results show that (1) both LSO and SSO positively impact production efficiency, but LSO has a stronger impact. (2) The relationship between LSO and APE is positively regulated by the agricultural production and operation environment, characteristics of the agricultural location, degree of farmers’ participation, and types of APE, and negatively regulated by the research situation. (3) The relationship between SSO and APE is negatively regulated by APE types and data types. Therefore, the government should promote agricultural dual-scale operation according to the local conditions through the complementary advantages of LSO and SSO, so as to fully release the promotion potential of APE

Changed Caecal Microbiota and Fermentation Contribute to the Beneficial Effects of Early Weaning with Alfalfa Hay, Starter Feed, and Milk Replacer on the Growth and Organ Development of Yak Calves

This study aimed to investigate the effect of early weaning by supplying calves with alfalfa hay, starter feed, and milk replacer on caecal bacterial communities and on the growth of pre-weaned yak calves. Ten 30-day-old male yak calves were randomly assigned to 2 groups. The maternal grazing (MG) group was maternally nursed and grazed, and the early weaning (EW) group was supplied milk replacer, starter feed, and alfalfa hay twice per day. Compared with the yak calves in the MG group, the yak calves in the EW group showed significantly increased body weight, body height, body length, and chest girth. When suffering to the potential mechanism of improved growth of yak calves, except for the enhanced ruminal fermentation, the significantly increased total volatile fatty acids, propionate, butyrate, isobutyrate, and valerate in the caecum in the EW group could also serve to promote the growth of calves. By using 16S rDNA sequencing, some significantly increased caecal phylum and genera, which were all related to the enhanced caecal fermentation by utilizing both the fibrous and non-fibrous carbohydrates, were identified in the EW group. In conclusion, early weaning of yak calves by supplying them with alfalfa hay, starter feed, and milk replacer is more beneficial to the growth of yak calves when compared with maternal grazing and nursing, in part due to alterations in caecal microbiota and fermentation

Ruminal Bacterial Community Successions in Response to Monensin Supplementation in Goats

Previous studies have demonstrated that the effects of monensin on methanogenesis and ruminal fermentation in ruminants were time-dependent. To elucidate the underlying mechanism, we investigated the ruminal bacterial community successions during the adaptation to monensin supplementation and subsequent withdrawal in goats. The experiment included a baseline period of 20 days followed by a treatment period of 55 days with 32 mg monensin/d and a washout period of 15 days. Monensin supplementation reduced the &alpha; diversity and changed the structure of ruminal microflora. The &alpha; diversity was gradually restored during adaption, but the structure was still reshaped. The temporal dynamics of 261 treatment- and/or time-associated ruminal bacteria displayed six patterns, with two as monensin-sensitive and four as monensin-resistant. The monensin sensitivity and resistance of microbes do not follow a clear dichotomy between Gram-positive and Gram-negative cell types. Moreover, the temporal dynamic patterns of different bacterial species within the same genus or family also displayed variation. Of note, the relative abundance of the total ruminal cellulolytic bacteria gradually increased following monensin treatment, and that of the total amylolytic bacteria were increased by monensin, independent of the duration. In conclusion, under the pressure of monensin, the ruminal ecosystem was reshaped through a series of succession processes, and the carbohydrate-degrading bacteria presented a higher level of adaptability

Heterogeneous reaction characteristics and their effects on homogeneous combustion of methane/air mixture in micro channels I. Thermal analysis

Catalytic combustion of methane/air mixture in various channels was numerically investigated to illuminate the heat characteristics of heterogeneous reactions (HTRs) and their effects on homogeneous reactions (HRs). A two-dimensional (2D) simulation model of channels with a width (d) of 2.00-2.82 mm was employed, which included detailed gas-phase and surface reaction mechanisms. Further, the heat transfer mechanisms were elucidated. HRs always occupied the main part of over 80% of the total released heat in all the cases. HTR is relatively amplified in narrower channels, and S (the ratio of heat released by HTR to that of all reactions) rises by several percentage as d decreases (S = 17.61% when d = 2.10 mm), and it is more effective to use a catalyst in the microcombustor with a smaller gap size to enhance combustion reaction rate and stability. The onsite-S showed a trend of "stable-decrease-peak-rapid increase-slow increase" along x, corresponding to preheating, homogeneous ignition, heterogeneous ignition (conversion of CO to CO2 and H-2 to H2O), intensive HTR stage (consumption of O, H, and OH and production of H2O and H-2), and complete consumption of reactants in the gas phase. The analysis about the heat sources for homogeneous ignition shows that homogeneous ignition was dominated by the preheating heat from hot gas downstream, and affected by transverse preheating heat. As d decreased, the preheating heat obtained from the transverse preheating increased by several percentages, even reaching to a similar value to preheating heat from hot gas downstream when d = 2.10 mm. The heat released by weak HTR only takes a small part of preheating heat of inlet mixture and homogeneous ignition. After homogeneous ignition, HR promoted the HTR to the maximum. Generally, HTR would delay the homogeneous ignition, enlarge the flame thickness, increase the peak of flame temperature and the exit gas temperature, and improve the completeness of combustion

Regulation of Nutritional Metabolism in Transition Dairy Cows: Energy Homeostasis and Health in Response to Post-Ruminal Choline and Methionine.

This study investigated the effects of rumen-protected methionine (RPM) and rumen-protected choline (RPC) on energy balance, postpartum lactation performance, antioxidant capacity and immune response in transition dairy cows. Forty-eight multiparous transition cows were matched and divided into four groups: control, 15 g/d RPC, 15 g/d RPM or 15 g/d RPC + 15 g/d RPM. Diet samples were collected daily before feeding, and blood samples were collected weekly from the jugular vein before morning feeding from 21 days prepartum to 21 days postpartum. Postpartum dry matter intake (DMI) was increased by both additives (P < 0.05), and energy balance values in supplemented cows were improved after parturition (P < 0.05). Both RPC and RPM decreased the plasma concentrations of non-esterified fatty acids (NEFA), β-hydroxybutyric acid (BHBA), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) (P < 0.05), but increased the plasma levels of glucose, very-low-density lipoprotein (VLDL) and apolipoprotein B100 (ApoB 100, P < 0.05). The supplements improved milk production (P < 0.05), and increased (P < 0.05) or tended to increase (0.05 < P < 0.10) the contents of milk fat and protein. The post-ruminal choline and methionine elevated the blood antioxidant status, as indicated by total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px) activity and the vitamin E concentration (P < 0.05), and reduced the plasma malondialdehyde (MDA) level (P < 0.05). Furthermore, RPM and RPC elevated the plasma interleukin 2 (IL-2) concentration and the CD4+/CD8+ T lymphocyte ratio in peripheral blood (P < 0.05). Alternatively, the levels of tumor necrosis factor-α (TNF-α) and IL-6 were decreased by RPM and RPC (P < 0.05). Overall, the regulatory responses of RPC and RPM were highly correlated with time and were more effective in the postpartum cows. The results demonstrated that dietary supplementation with RPC and RPM promoted energy balance by increasing postpartal DMI and regulating hepatic lipid metabolism, improved postpartum lactation performance and enhanced antioxidant capacity and immune function of transition dairy cows

High rumen degradable starch diet induced blood bile acids profile changes and hepatic inflammatory response in dairy goats

The objective of this study was to reveal the effect of rumen degradable starch (RDS) on bile acid metabolism and liver transcription in dairy goats using metabolomics and transcriptomics. Eighteen Guanzhong dairy goats of a similar weight and production level (body weight = 45.8 ± 1.54 kg, milk yield = 1.75 ± 0.08 kg, and second parity) were randomly assigned to 3 treatment groups where they were fed a low RDS (LRDS, RDS = 20.52% DM) diet, medium RDS (MRDS, RDS = 22.15% DM) diet, or high RDS (HRDS, RDS = 24.88% DM) diet, respectively. The goats were fed with the experimental diets for 5 weeks. On the last day of the experiment, all goats were anesthetized, and peripheral blood and liver tissue samples were collected. The peripheral blood samples were used in metabolomic analysis and white blood cell (WBC) count, whereas the liver tissue samples were used in transcriptomic analysis. Based on the metabolomics results, the relative abundances of primary bile acids in the peripheral blood were significantly reduced in the group that was fed the HRDS diet (P < 0.05). The WBC count was significantly increased in the HRDS group compared with that in the LRDS and MRDS groups (P < 0.01), indicating that there was inflammation in the HRDS group. Transcriptomic analysis showed that 4 genes related to bile acid secretion (genes: MDR1, RXRα, AE2, SULT2A1) were significantly downregulated in the HRDS group. In addition, genes related to the immune response were upregulated in the HRDS group, suggesting the HRDS diet induced a hepatic inflammatory response mediated by lipopolysaccharides (LPS) (gene: LBP), activated the Toll-like receptor 4 binding (genes: S100A8, S100A9) and the NF-kappa B signaling pathway (genes: LOC106503980, LOC108638497, CD40, LOC102180880, LOC102170970, LOC102175177, LBP, LOC102168903, LOC102185461, LY96 and CXCL8), triggered inflammation and complement responses (genes: C1QB, C1QC, and CFD). The HRDS diet induced a hepatic inflammatory response may be mediated by activating the Toll-like receptor 4 binding and NF-kappa B signaling pathway after free LPS entered the liver. The changes of bile acids profile in blood and the down-regulation of 4 key genes (MDR1, RXRα, AE2, SULT2A1) involved in bile secretion in liver are probably related to liver inflammation