Propionate promotes gluconeogenesis by regulating mechanistic target of rapamycin (mTOR) pathway in calf hepatocytes.

Enhancing hepatic gluconeogenesis is one of the main modes of meeting the glucose requirement of dairy cows. This study attempted to determine whether the gluconeogenesis precursor propionate had an effect on the expression of the main genes involved in gluconeogenesis in calf hepatocytes and elucidate the associated mechanisms. Calf hepatocytes were obtained from 5 healthy calves (1 d old; 30 to 40 kg) and exposed to 0-, 1-, 2.5-, or 5-mM sodium propionate (NaP), which is known to promote the expression of genes involved in the gluconeogenesis pathway, including fructose 1,6-bisphosphatase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase. With regard to the underlying mechanism, propionate promoted the expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, hepatocyte nuclear factor 4, and forkhead box O1 (transcription factors that regulate the expression of hepatic gluconeogenic genes) by promoting mammalian target of rapamycin complex 1 (mTORC1), but inhibiting mTORC2 activity (P < 0.01). We also established a model of palmitic acid (PA)-induced hepatic injury in calf hepatocytes and found that PA could inhibit the gluconeogenic capacity of calf hepatocytes by suppressing the expression of gluconeogenic genes, inhibiting mTORC1, and promoting the activity of mTORC2 (P < 0.01). In contrast, NaP provided protection to calf hepatocytes by counteracting the inhibitory effect of PA on the gluconeogenic capacity of calf hepatocytes (P < 0.05). Collectively, these findings indicate that NaP enhances the gluconeogenic capacity of calf hepatocytes by regulating the mTOR pathway activity. Thus, in addition to improving the glucose production potential, propionate may have therapeutic potential for the treatment of hepatic injury in dairy cows.

Differences in serum metabolome profile explain individual variation in growth performance of young goats.

High growth rates and body weight are important traits of young dairy goats that can shorten generation intervals, improve animal performance, and increase economic benefits. In the present study, ninety-nine, 6-month-old, female goats were fed with the same diet and kept under the same management condition. The ten goats with highest average daily gain (ADG, HADG, 135.27 ± 4.59 g/d) and ten goats with lowest ADG (LADG, 87.74 ± 3.13 g/d) were selected to identify the key serum metabolites associated with ADG, and to investigate the relationships of serum metabolome profiles with digestive tract microbiota. The results showed that a total of 125 serum metabolites were significantly different between HADG and LADG. Of these, 43 serum metabolites were significantly higher levels in HADG, including D-ornithine, l-glutamine, L-histidine, carnosine, LysoPC (16:1(9Z)/0:0), DCTP and hydroxylysine, while, 82 serum metabolites were significantly higher levels in LADG, including P-salicylic acid and deoxycholic acid 3-glucuronide. Pathway analysis indicated that these different metabolites were mainly involved in amino acid and lipid metabolism. Furthermore, Spearman's rank correlation analysis revealed that these differential serum metabolites were correlated with ADG and ADG-related bacteria. Notably, serum hydroxylysine and L-histidine could be used as biomarkers for distinguishing HADG and LADG goats, with an accuracy of >92.0%. SIGNIFICANCE: Our study confirms that individual microbiota and metabolic differences contribute to the variations of growth rate in young goats. Some serum metabolites may be useful in improving the growth performance of young goats, which provides directions for developing further nutritional regulation in the goat industry to achieve healthy feeding and efficiency enhancement.

Replacement of forage fiber with non-forage fiber sources in dairy cow diets changes milk extracellular vesicle-miRNA expression.

Milk is a dynamic source of nutrients and bioactive factors, varying with the nutrition status of the cattle. We partly replaced alfalfa hay with whole cotton seed and soybean hull (non-forage fiber source, NFFS) in the feed formula of treated cows and evaluated the effects on milk extracellular vesicles (EVs). The NFFS supplement did not affect the shape of milk EVs observed using a transmission electron microscope. Nanoparticle tracking analysis revealed that the EV concentration increased significantly in treated cows (P = 0.019), with the peak diameter unaffected by the treatment. The EV-RNA concentration and small RNA content, particularly rRNAs and tRNAs, significantly increased in the treated cows (P < 0.05). The other small RNAs, i.e. miRNAs, cis-regulatory elements, snRNAs, and other Rfam RNAs showed no significant difference between the two groups. Totally 276 milk EV-miRNAs were identified. Thirteen miRNAs, accounting for 76%, in the highly expressed top 20, were immune-related. In addition, 9 differently expressed miRNAs (4 up-regulated and 5 down-regulated) were identified (P < 0.05). Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the differently expressed miRNAs were related to the citrate cycle, fat digestion and absorption process, taurine and hypo-taurine metabolism, and glycosphingolipid biosynthesis. This study documents the milk nutrition assessment from macromolecules, especially EVs.

Effects of 2-aryl-1-cyano-1,2,3,4-tetrohydroisoquinolines on apoptosis induction mechanism in NB4 and MKN-45 cells.

Our previous study found that 2-aryl-1-cyano-1,2,3,4-tetrahydroisoquinolines (CATHIQs) have excellent anti-cancer activity and obvious apoptosis induction phenomenon. As our continuing research, this study further explored their underlying molecular mechanism of apoptosis induction in cancer cells. Flow cytometry analysis showed that the NB4 cells treated by 1-cyano-2-(2-fluorophenyl)-1,2,3,4-tetrahydroisoquinoline or the MKN-45 cells treated by 1-cyano-2-(4-trifluoromethylphenyl)-1,2,3,4-tetrahydroisoquinoline for 48 h were at early stage of apoptosis, and the cell cycle arrest was only slightly affected. Apoptosis rates of the cells significantly increase with the treatment concentration of the compounds. The compounds could significantly decrease the activities of SOD, raise the MDA level and promote the LDH leakage, suggesting that the excessive formation of ROS should be involved in the cell apoptosis. Western blot analysis showed that the compounds improved both Bax/Bcl-2 ratio and cleavages of procaspase-3, promoted efflux of cytochrome c to cytosol and phosphorylation of p38 and JNK, and attenuated phosphorylations of Akt and ERK. Together, inhibitions of PI3K/Akt and ERK and activation of p38 mediated the compounds-induced apoptosis through modulating the mitochondrial pathway and/or ROS production.

3H-leucine single-injection method for determining endogenous amino acid losses of broilers.

OBJECTIVE: A 3H-leucine (3H-Leu) single-injection method was proposed for determining the endogenous amino acid losses of broilers. This method was based on the hypothesis that the ratio of the specific radioactivity (SR) of endogenous Leu in excreta (SRe) to that of free Leu in trichloroacetic acid-soluble plasma (SRp) remains constant after a single subcutaneous injection of 3H-Leu into birds fed different diets. METHODS: Two experiments were designed to clarify this hypothesis. In experiment 1, 40 female broilers were randomly divided into four groups and were force-fed a nitrogen-free diet (NFD), NFD plus enzyme-hydrolyzed casein (EHC), 5% crude protein (CP) and SBM (soybean meal), or 20% CP-SBM. In experiment 2, 24 broilers were randomly divided into four groups and were fasted or force-fed the NFD, 20% CP-SBM, or 20% CP and cottonseed meal (CSM) diet. After the forced feeding, broilers were administered 3H-Leu by a single subcutaneous injection at a rate of 30 µCi/kg of body weight. Blood samples were taken at 5 min, 30 min, 4 h, 24 h, 36 h, and 48 h after the injection. The excreta were totally collected and pooled over the 48-h experiment. RESULTS: The ratios of SRe to SRp remained the same for the birds force-fed the NFD, NFD+EHC, and 5% CP-SBM diets in experiment 1 and for the birds fasted and force-fed the NFD diet in experiment 2. The proportions of endogenous Leu to total Leu in excreta were 72.8%, 61.4%, and 57.5% for birds force-fed with the 20% CP-SBM diet in experiment 1 and 20% CP-SBM and 20% CP-CSM diets in experiment 2, respectively. Broilers fed the 5% CP-SBM and 20% CP-SBM diets excreted more (P<0.05) endogenous Leu than those fed the NFD and NFD+EHC diets in experiment 1. Broilers fed the 20% CP-SBM diet excreted more (P<0.05) endogenous Leu than those fed the NFD diet and fasted and the 20% CP-CSM diet was intermediate (P>0.05) in experiment 2. CONCLUSION: The present study verified the hypothesis that the ratio of SRe to SRp remains constant after a single subcutaneous injection of 3H-Leu into broilers and proposes a new method to determine endogenous amino acid losses of broilers.