Dietary Supplementation of Leucine in Premating Diet Improves the Within-Litter Birth Weight Uniformity, Antioxidative Capability, and Immune Function of Primiparous SD Rats

Supplementation with Astragalus Root Powder Promotes Rumen Microbiota Density and Metabolome Interactions in Lambs

The gut microbiota is highly symbiotic with the host, and the microbiota and its metabolites are essential for regulating host health and physiological functions. Astragalus, as a feed additive, can improve animal immunity. However, the effects of Astragalus root powder on the rumen microbiota and their metabolites in lambs are not apparent. In this study, thirty healthy Hu sheep lambs with similar body weights (17.42 ± 2.02 kg) were randomly selected for the feeding experiment. Lambs were fed diets supplemented with 0.3% Astragalus root powder, and the rumen microbiota density and metabolome were measured to determine the effects of Astragalus on the health of lambs in the rumen. The results showed that the relative abundance of Butyrivibrio fibrisolvens (Bf), Ruminococcus flavefaciens (Rf), Succiniclasticum (Su), and Prevotella (Pr) in the rumen was increased in the Astragalus group (p < 0.01), and metabolic profiling showed that the metabolites, such as L-lyrosine and L-leucine, were upregulated in the Astragalus group (p < 0.01). KEGG functional annotation revealed that upregulated metabolites were mainly enriched in the pathways of amino acid metabolism, lipid metabolism, fatty acid biosynthesis, and bile secretion in the Astragalus group, and downregulated metabolites were enriched in the pathways of methane metabolism and other pathways. Correlation analysis revealed that butyric acid was positively correlated with Roseburia and Blautia (p < 0.05) and negatively correlated with Desulfovibrio (p < 0.05). Thus, by analyzing the interactions of Astragalus root powder with the density of rumen microorganisms and their metabolites in lambs, it was shown that Astragalus root powder could improve the structure of rumen microbiota and their metabolites and then participate in the regulation of amino acid metabolism, lipid metabolism, immune metabolism, and other pathways to improve the efficiency of energy absorption of the lambs.

Leucine mediates cognitive dysfunction in early life stress-induced mental disorders by activating autophagy

Objectives

To explore the relationship between leucine in cerebrospinal fluid (CSF) and cognitive dysfunction in rats with early life stress (ELS) induced mental illness, and pathophysiological mechanism involved.

Methods

The maternal separation (MS), an animal paradigm used widely as a preclinical model of ELS which is one of the important risk factors for mental disorders. Behavioral experiments including open-field test, sucrose preference, object recognition and Morris water maze tests, Nissl staining, transmission electron microscopy and WES were employed in the present study.

Results

The behavioral results showed that MS rats were more prone to cognitive impairment and depression-and-anxiety-like behaviors than controls, including spatial self-exploration ability, memory ability, and spatial learning and memory function. Nissl staining analysis indicated that the number of neurons in the CA1 and CA3 regions of the hippocampus significantly decreased and the arrangement of nerve cells was abnormal. The leucine levels were decreased in the CSF of MS rats and highly correlated with the number of hippocampal neurons, and yet leucine supplementation improved the degree of MS-induced cognitive impairment. Furthermore, there were autophagosomes in the hippocampus of the low-leucine diet rats of the control and MS group but not in the high-leucine diet MS group by transmission electron microscopy. The protein expression of Beclin-1 in the hippocampus was significantly increased in the MS normal diet group and MS low-leucine diet group, yet decreased in the MS high-leucine diet group compared with the MS low-leucine diet group. Meanwhile, the Bcl-2/Bax ratio was significantly decreased in the control low-leucine diet group, MS normal diet group and MS low-leucine diet group. Ultimately, in vitro experiments suggested that leucine deficiency could activate neuronal autophagy including enhanced LC3II/LC3I and mRFP-GFP-LC3, which was consistent with the in vivo results, and the cell apoptosis rate and lactate dehydrogenase (LDH) cytotoxicity were also increased with leucine deficiency, while the above effects could be partly reversed by autophagy inhibitor treatment.

Conclusions

MS model caused adult male rats to be susceptible to cognitive dysfunction, which may regulate autophagy in hippocampal neurons through leucine metabolism in CSF.

Effects of Dietary Choline Levels During Pregnancy on Reproductive Performance, Plasma Metabolome and Gut Microbiota of Sows

This study investigated the effects of dietary choline levels during gestation on reproductive performance of sows. In addition, the plasma metabolome and gut microbiota of sows was studied. A total of 260 multiparous sows were allocated to five dietary treatment groups with increasing choline concentrations (1,050, 1,450, 1,850, 2,250, and 2,650 mg/kg) in a randomized complete block design. The sows were fed experimental diets from breeding until farrowing and a common lactating diet during lactation. The results showed that the backfat (BF) gain of sows during gestation, individual birth weight for total piglets born, piglets born alive, average piglet weight at weaning increased linearly (P < 0.05), whereas the within-litter birth weight variation coefficient (CV) of piglets born alive and suckling piglet mortality decreased linearly (P < 0.05) as dietary choline level increased. A quadratic effect of dietary choline level was observed for the average daily feed intake (ADFI) of sows during lactation (P < 0.05). ADFI was maximized when the dietary choline concentration reached 1,910 mg/kg. Plasma H2O2 concentration at day 30 of gestation in the 1,050 mg/kg group was greater than that in the 1,850 and 2,650 mg/kg groups (P < 0.05). Plasma metabolomics identified 46 metabolites among the three groups. Specifically, plasma concentrations of trimethylamine-N-oxide (TMAO), dopamine, and L-proline increased while 1-methylhistidine concentration decreased as dietary choline levels increased. In addition, bacterial observed species and richness (Chao 1 and ACE) at day 110 of gestation decreased as dietary choline levels increased (P < 0.05). For the gut microbiota composition, the enhanced dietary choline level decreased the abundance of phylum Proteobacteria (P < 0.05) and increased the abundance of phylum Actinobacteria (P < 0.05) at day 30 of gestation. Compared with the 1,050 mg/kg group, the abundance of genus Terrisporobacter was less in the 1,850 mg/kg group, and genera Bacillus and Cellulomonas were greater in the 2,650 mg/kg group. In summary, increasing dietary choline levels improved the birth weight, uniformity of neonatal piglets and litter performance during lactation. This may be associated with better antioxidant capability, metabolic status, and gut microbiota of sows during gestation.

Role of Dietary Amino Acids and Nutrient Sensing System in Pregnancy Associated Disorders

Defective implantation is related to pregnancy-associated disorders such as spontaneous miscarriage, intrauterine fetal growth restriction and others. Several factors proclaimed to be involved such as physiological, nutritional, environmental and managemental that leads to cause oxidative stress. Overloading of free radicals promotes oxidative stress, and the internal body system could not combat its ability to encounter the damaging effects and subsequently leading to pregnancy-related disorders. During pregnancy, essential amino acids display important role for optimum fetal growth and other necessary functions for continuing fruitful pregnancy. In this context, dietary amino acids have received much attention regarding the nutritional concerns during pregnancy. Arginine, glutamine, tryptophan and taurine play a crucial role in fetal growth, development and survival while ornithine and proline are important players for the regulation of gene expression, protein synthesis and angiogenesis. Moreover, amino acids also stimulate the mammalian target of rapamycin (mTOR) signaling pathway which plays a central role in the synthesis of proteins in placenta, uterus and fetus. This review article explores the significances of dietary amino acids in pregnancy development, regulation of nutrient-sensing pathways such as mTOR, peroxisome proliferator-activated receptors (PPARs), insulin/insulin-like growth factor signaling pathway (IIS) and 5' adenosine monophosphate-activated protein kinase (AMPK) which exhibit important role in reproduction and its related problems. In addition, the antioxidant function of dietary amino acids against oxidative stress triggering pregnancy disorders and their possible outcomes will also be enlightened. Dietary supplementation of amino acids during pregnancy could help mitigate reproductive disorders and thereby improving fertility in animals as well as humans.

Leucine Supplementation: A Novel Strategy for Modulating Lipid Metabolism and Energy Homeostasis

Lipid metabolism is an important and complex biochemical process involved in the storage of energy and maintenance of normal biological functions. Leucine, a branched amino acid, has anti-obesity effects on glucose tolerance, lipid metabolism, and insulin sensitivity. Leucine also modulates mitochondrial dysfunction, representing a new strategy to target aging, neurodegenerative disease, obesity, diabetes, and cardiovascular disease. Although various studies have been carried out, much uncertainty still exists and further studies are required to fully elucidate the relationship between leucine and lipid metabolism. This review offers an up-to-date report on leucine, as key roles in both lipid metabolism and energy homeostasis in vivo and in vitro by acceleration of fatty acid oxidation, lipolysis, activation of the adenosine 5'-monophosphate-activated protein kinase (AMPK)-silent information regulator of transcription 1 (SIRT1)-proliferator-activated receptor γ coactivator-1α (PGC-1α) pathway, synthesis, and/or secretion of adipokines and stability of the gut microbiota.

Glucosamine Supplementation in Premating Drinking Water Improves Within-Litter Birth Weight Uniformity of Rats Partly through Modulating Hormone Metabolism and Genes Involved in Implantation

Within-litter birth weight variation in multiparous animals has become a big issue due to high incidence of low birth weight neonates, which gives rise to high preweaning mortality and morbidity. Foetus with various birth weights is the outcome of diverse embryos competence which is affected by oocyte quality. Glucosamine (GlcN) has been reported to be involved in oocyte maturation; however, its effect on pregnant outcomes remains unknown. The present study was conducted to investigate the effects of premating GlcN supplementation via drinking water on within-litter birth weight variation and its underlying mechanism. Fifty eight Sprague-Dawley female rats were randomly assigned to one of two groups with normal drinking water or drinking water supplemented with 0.5 mM GlcN from six to eight weeks old. Variation of within-litter birth weight in the GlcN group was 5.55%, significantly lower compared with 8.17% in the control group. Birth weight was significantly increased in the GlcN group (2.27 ± 0.06) compared with the control group (2.08 ± 0.04). Both absolute and relative weights of the ovary at the end of GlcN treatment were higher in the GlcN group than in the control group (P < 0.05). In the GlcN group, there were more successfully implanted blastocysts (13.38 ± 0.63 and 15.75 ± 0.59 in the control and treatment group, respectively) with more uniform distribution along the two uterine horns compared with the control group. Besides, gene expressions of Alk3 and Bmp2 were increased in the implantation sites, while IGF-1 and Mucin-1 were decreased significantly in rats administrated with GlcN. Maternal progesterone, estradiol, and IGF-1 concentrations on D 19.5 were significantly increased, while insulin and total cholesterol levels were significantly decreased in contrast with control dams. In summary, the administration of 0.5 mM GlcN solution before mating reduced within-litter birth weight variation, accompanied with increased fetal weight. Further investigation indicated that the improved outcome of pregnancy results at least partly from the increased ovary weights of the rats, the homogeneous embryo developmental competence, the enhanced receptivity of the uterine environment, and the adjusted maternal hormone levels.