Stimulation of myogenesis by ascorbic acid and capsaicin.

Myogenesis is a complex process regulated by several factors. This study evaluated the functional interaction between vitamin C and a high dose of capsaicin (a potential endoplasmic reticulum (ER) stress inducer) on myogenesis. After the induction of differentiation, treatment with ascorbic acid or ascorbic acid phosphate (AsAp) alone had minimal effects on myogenesis in C2C12 cells. However, treatment with capsaicin (300 µM) in undifferentiated C2C12 cells increased the expression levels of genes related to ER stress as well as oxidative stress. Myogenesis was effectively enhanced in C2C12 cells treated with a combination of capsaicin (300 µM) for one day before differentiation stimulation and AsAp for four days post-differentiation; subsequently, thick and long myotubes formed, and the expression levels of myosin heavy chain (MYH) 1/2 and Myh1, Myh4, and Myh7 increased. Considering that mild ER stress stimulates myogenesis, AsAp may elicit myogenesis through the alleviation of oxidative stress-induced negative effects in capsaicin-pretreated cells. The enhanced expression of Myh1 and Myh4 coincided with the expression of Col1a1, a type I collagen, suggesting that the fine-tuning of the myogenic cell microenvironment is responsible for efficient myogenesis. Our results indicate that vitamin C is a potential stimulator of myogenesis in cells, depending on the cell context.

Effect of niacin supplementation in long-distance transported steer calves.

Long-distance transportation has negative impacts on production and health in cattle. Feed and water are routinely deprived from cattle during transportation. We investigated whether niacin supplementation could improve niacin nutrition and mitigate the adverse effect of transportation with feed and water deprivation in steer calves. We also studied the adverse effect of feed and water deprivation in nontransported steer calves. Twelve calves were assigned to feed and water deprivation for 2 days, or full access to feed and water in experiment 1. Ten calves were assigned to 2-day transportation with feed and water deprivation, or the transportation with feed and water deprivation, but with supplementation of rumen-protected niacin at 100 g/day per head in experiment 2. Bodyweight was measured and blood was collected for 32 days in each experiment. Feed and water deprivation temporarily decreased serum glucose concentrations and bodyweight gain. Transportation with deprivation of feed and water caused a temporal decrease in bodyweight gain and serum albumin concentration, and a continuous decrease in serum glucose and total cholesterol concentrations, which was suppressed by niacin supplementation. Niacin supplementation increased blood niacin concentration. These results suggest that niacin supplementation mitigates adverse effects of transportation with feed and water deprivation in steer calves.

Effect of long-distance transportation on serum metabolic profiles of steer calves.

Long-distance transportation is sometimes inevitable in the beef industry because of the geographic separation of major breeding and fattening areas. Long-distance transportation negatively impacts production and health of cattle, which may, at least partly, result from the disturbance of metabolism during and after transportation. However, alteration of metabolism remains elusive in transported cattle. We investigated the effects of transportation on the metabolomic profiles of Holstein steer calves. Non-targeted analysis of serum concentrations of low molecular weight metabolites was performed by gas chromatography mass spectrometry. Transportation affected 38 metabolites in the serum. A pathway analysis suggested that 26, 10, and 10 pathways were affected immediately after transportation, and 3 and 7 days after transportation, respectively. Some pathways were disturbed only immediately after transportation, likely because of feed and water withdrawal during transit. Nicotinate and nicotinamide metabolism, and citric acid cycle were affected for 3 days after transportation, whereas propionate metabolism, phenylalanine and tyrosine metabolism were affected throughout the experiment. Four pathways were not affected immediately after transportation, but were altered thereafter. These results suggested that many metabolic pathways had marked perturbations during transportation. Metabolites such as citric acid, propionate, tyrosine and niacin can be candidate supplements for mitigating transportation-induced adverse effects.

Brown adipose tissue in cetacean blubber.

Brown adipose tissue (BAT) plays an important role in thermoregulation in species living in cold environments, given heat can be generated from its chemical energy reserves. Here we investigate the existence of BAT in blubber in four species of delphinoid cetacean, the Pacific white-sided and bottlenose dolphins, Lagenorhynchus obliquidens and Tursiops truncates, and Dall's and harbour porpoises, Phocoenoides dalli and Phocoena phocoena. Histology revealed adipocytes with small unilocular fat droplets and a large eosinophilic cytoplasm intermingled with connective tissue in the innermost layers of blubber. Chemistry revealed a brown adipocyte-specific mitochondrial protein, uncoupling protein 1 (UCP1), within these same adipocytes, but not those distributed elsewhere throughout the blubber. Western blot analysis of extracts from the inner blubber layer confirmed that the immunohistochemical positive reaction was specific to UCP1 and that this adipose tissue was BAT. To better understand the distribution of BAT throughout the entire cetacean body, cadavers were subjected to computed tomography (CT) scanning. Resulting imagery, coupled with histological corroboration of fine tissue structure, revealed adipocytes intermingled with connective tissue in the lowest layer of blubber were distributed within a thin, highly dense layer that extended the length of the body, with the exception of the rostrum, fin and fluke regions. As such, we describe BAT effectively enveloping the cetacean body. Our results suggest that delphinoid blubber could serve a role additional to those frequently attributed to it: simple insulation blanket, energy storage, hydrodynamic streamlining or contributor to positive buoyancy. We believe delphinoid BAT might also function like an electric blanket, enabling animals to frequent waters cooler than blubber as an insulator alone might otherwise allow an animal to withstand, or allow animals to maintain body temperature in cool waters during sustained periods of physical inactivity.

Downregulation of Pgc-1α expression by tea leaves and their by-products.

Previous studies indicate that muscle Pgc-1α expression governs the proportion of muscle fibre types. As a first step in using diet to manipulate the proportion of muscle fibre types by using Pgc-1α expression, the present study investigates the modulation of Pgc-1α expression by feedstuffs. A luciferase-based Pgc-1α reporter construct (Pgc-1α(-2553)-luc) that contains the mouse Pgc-1α promoter (-2553 to +78 bp) was prepared. A screen of ethanol extracts from 33 feedstuffs indicated that oolong tea and roasted green tea extracts decreased Pgc-1α(-2553)-luc expression in C2C12 myoblasts. The transcriptional repression of Pgc-1α by tea leaf extracts was reproduced in hepatic HepG2 cells. We further examined the effects of the alcohol extracts of tea waste and its silage on Pgc-1α transcription; the tea waste silage extract inhibited Pgc-1α transcription. Treatment with the extracts of raw tea leaves, tea waste and tea waste silage effectively decreased Pgc-1α mRNA levels during myogenesis of myosatellite cells. The present results suggest that tea leaves and their by-products could be used to modulate proportions of muscle fibre types.

Regulatory responses to excess zinc ingestion in growing rats.

The growth of weaning piglets is effectively improved by feeding a high-Zn diet (3000 mg Zn/kg of diet). The present study examined whether feeding a diet supplemented with Zn (1016-3000 mg/kg) for 10 d induces growth benefits in rats. In addition, tissue weight, Zn content of tissues and expression of Zn transporters were examined in these rats. Zn supplementation did not significantly increase body weight. Breaking line model analyses indicated that the weight of the pancreas, the organ most sensitive to excess Zn, significantly decreased with increasing Zn intake beyond 15·2 mg/d. Excess Zn has been suggested to accumulate in the liver, kidney and bone in order to protect the pancreas. Zn concentrations in the plasma, liver, kidney and femur increased with increasing Zn intake up to approximately 30 mg/d, whereas those in the pancreas increased up to 8·4 mg/d and decreased by Zn intake beyond 8·4 mg/d. The expression levels of the Zn transporters Zip4 and ZnT1 in the intestinal epithelium were significantly lower in rats fed a diet supplemented with 1016 mg/kg Zn compared to those fed the basal diet. The present study reveals that (1) excess Zn intake does not accelerate growth in rats, but is detrimental to the pancreas, (2) the excess Zn is effectively accumulated in the liver, kidney and bone, without sufficient protection of the pancreas and (3) expression of Zn transporters is down-regulated in response to excess Zn intake.

Brewer's yeast efficiently degrades phytate phosphorus in a corn-soybean meal diet during soaking treatment.

Microbes such as yeast and Aspergillus are known to produce phytase, and Aspergillus phytase has been used as a feed additive for improving phytate-phosphorus bioavailability in monogastric animals. We measured phytase activity in some by-products from fermented food and beverage productions by yeast and Aspergillus. The phytase activity was as high as 3577 and 2225 PU/kg DM in raw and dried brewer's yeasts, respectively. On the other hand, the phytase activity was approximately 400 PU/kg DM in white-wine yeast and red-wine yeast. The phytase activity was further low in natto (fermented soybean) residue, soy sauce cake, rice brewer's grain and the activity was not detected in dried corn-barley distiller's grain with soluble and sweet-potato distiller's residue. The stability of phytase against pepsin was much lower in the brewer's yeast than in an Aspergillus phytase preparation. On the other hand, the addition of raw brewer's yeast effectively degraded phytate phosphorus in a corn-soybean meal diet during soaking. These results suggest that phytase in the examined by-products is not suitable for the phytase source of conventional diets, but that the soaking treatment with a raw brewer's yeast is an alternative method for improving phytate-phosphorus bioavailability in corn-soybean meal diets for pigs.

Factors affecting struvite (MgNH4PO4.6H2O) crystallization in feline urine.

Factors affecting struvite, a magnesium-ammonium-phosphate complex (MgNH(4)PO(4).6H(2)O), in feline urine were evaluated. Incubation of just "urine mineral (UM)" solution, in which mineral concentrations are compatible with those in feline urine, for 4 h at 37 degrees C did not induce the formation of crystals. Similarly, incubation of urine alone did not produce crystals. However, struvite crystals were formed by the addition of urine to UM solution. Mg, NH(3) and P were all required for urine-induced struvite crystallization. The lower molecular weight (LMW) fraction of urine was essential for struvite crystal formation, and the higher molecular weight (HMW) fraction enhanced formation of LMW-induced struvite crystals. The effects of urine proteins further fractionated by column chromatography were examined. A protein at >250 kDa and cauxin, a major urine protein recently identified as a regulator of felinine production, potentiated struvite crystal formation induced by the LMW fraction. In contrast, Tamm-Horsfall glycoprotein, a urine protein thought to promote struvite crystallization, did not have this activity. The present study reveals a novel mechanism of feline struvite crystallization.

Identification of tocopherol-associated protein as an activin/TGF-beta-inducible gene in mast cells.

Previous studies have demonstrated that treatment with activin A and TGF-beta(1), members of the TGF-beta family, stimulated maturation of mouse bone marrow-derived cultured mast cells (BMMC), which was characterized by morphology and gene expression of mouse mast cell proteases (mmcps). In order to gain a better understanding of activin A- and TGF-beta(1)-induced maturation in mast cells, we investigated the genes that were up-regulated in response to treatment with these two members of the TGF-beta family. The cDNA microarray analyses indicated that in BMMC, five genes were induced by treatment with 4 nM activin A for 2 h. Tocopherol-associated protein (Tap) was one of the induced genes, and the Tap induction in response to activin A treatment was confirmed by real-time RT-PCR analyses. Treatment with TGF-beta(1) at 200 pM but not BMP-2 at 4 nM also increased Tap gene transcript in BMMC. Activin A-induced Tap expression was detected in BMMC but not in RAW264 macrophage-like cells, B16 melanoma cells or P19 embryonic carcinoma cells. Treatment with >1 muM SB431542, an inhibitor of activin and TGF-beta type I receptors ALK4/5, reduced responsiveness of Tap expression to TGF-beta(1), whereas <0.5 microM SB431542 effectively reduced TGF-beta(1)-induced expression of mmcp-1 and mmcp-7. These results suggest that inhibitory effects of SB431542 are different between TGF-beta-induced genes. Reporter assays indicated that Tap expression enhances transcription mediated by the activin/TGF-beta pathway. Thus, the present results suggest that Tap induction in response to activin/TGF-beta occurs predominantly in mast cells and serves as a positive regulator in activin/TGF-beta signaling.

Evaluation of effects of dietary carbohydrate on formation of struvite crystals in urine and macromineral balance in clinically normal cats.

OBJECTIVE: To evaluate effects of dietary carbohydrate on urine volume; struvite crystal formation; and calcium, phosphorus, and magnesium balance in clinically normal cats. ANIMALS: 21 healthy adult cats (15 sexually intact males and 6 sexually intact females). PROCEDURE: Diets containing no carbohydrate source (control diet), control plus starch, or control plus fiber were given in a 3 X 3 Latin-square design. The diets were available ad libitum in study 1 (n = 12) and given under restrictions in study 2 (9) to equalize daily intakes of crude protein among the 3 groups. Formation of struvite crystals and balance of calcium, phosphorus, and magnesium were measured. RESULTS: Urine volume was lower in the starch group and fiber group in study 1, whereas no differences were detected among the groups in study 2. Urinary pH and struvite activity product were higher in the starch group in both studies, and the fiber group also had higher struvite activity product in study 2. In both studies, urinary concentrations of HCl-insoluble sediment were higher in the starch group and fiber group. In the fiber group, a net loss of body calcium, phosphorus, and magnesium was detected in study 2. CONCLUSIONS AND CLINICAL RELEVANCE: Starch and fiber in diets potentially stimulate formation of struvite crystals. Hence, reducing dietary carbohydrate is desirable to prevent struvite urolith formation. In addition, a net loss of body calcium, phosphorus, and magnesium during feeding of the fiber diet suggests that dietary inclusion of insoluble fiber could increase macromineral requirements of cats.

Effects of a high-protein diet versus dietary supplementation with ammonium chloride on struvite crystal formation in urine of clinically normal cats.

OBJECTIVE: To evaluate the effects of a high-protein diet versus dietary supplementation with ammonium chloride (NH4Cl) on struvite crystal formation in the urine of clinically normal cats by measuring the urine concentration of hydrochloric acid (HCl)-insoluble sediment, urine pH, struvite activity product (SAP), number of struvite crystals in urine, and urine volume. ANIMALS: 23 healthy adult cats. PROCEDURE: Urine was fractionated by centrifugation with subsequent extraction of the sediment with 1 N HCl (study 1). Diets containing either 29% crude protein or 55% crude protein were fed to cats in a crossover trial of 3 weeks/period (study 2). Diets supplemented with either sodium chloride (NaCl) or NH4Cl were fed, by use of a 3 x 3 Latin-square design with 3 wk/period (study 3). In studies 2 and 3, urine samples were collected for the last 7 days of each period. RESULTS: The HCl-insoluble sediment contained Tamm-Horsfall glycoprotein (THP; study 1). The high-protein diet (study 2) and dietary supplementation with NH4Cl (study 3) resulted in a decrease in urine pH, SAP, and the number of struvite crystals in urine. However, the high-protein diet decreased urine concentrations of HCl-insoluble sediment containing THP (study 2), in contrast to the NH4Cl supplementation that increased urine volume without a significant effect on the urine concentration of the HCl-insoluble sediment (study 3). CONCLUSIONS AND CLINICAL RELEVANCE: Our results indicate that compared with dietary supplementation with NH4Cl, the high-protein diet is preferable as a urine acidifier for the prevention of struvite crystal formation in clinically normal cats.