Dietary supplementation with arginine and glutamic acid alters the expression of amino acid transporters in skeletal muscle of growing pigs.

Sixty Duroc × Large White × Landrace pigs with an average initial body weight (BW) of 77.1 ± 1.3 kg were selected to investigate the effects of dietary supplementation with arginine (Arg) and/or glutamic acid (Glu) on free amino acid (FAA) profiles, expression of AA transporters, and growth-related genes in skeletal muscle. The animals were randomly assigned to one of five treatment groups (basic diet, iso-nitrogenous, Arg, Glu, and Arg + Glu groups). The results showed that plasma Glu concentration was lowest in the Arg + Glu group and highest in the Glu group (P < 0.05). In the longissimus dorsi (LD) muscle, the concentrations of histidine, Arg, and taurine in the Arg + Glu group were higher, and the concentrations of 3-methylhistidine was lower, than in the basic diet group (P < 0.05). The mRNA levels of ASC amino acid transporter-2 (ASCT2), L-type AA transporter 1, and sodium-coupled neutral amino acid transporter 2 in the LD muscle, as well as the mRNA levels of ASCT2 and proton-assisted amino acid transporter in the biceps femoris (BF) muscle, were higher in the Arg + Glu group compared to the basic diet group (P < 0.05). The mRNA levels of the muscle-specific RING finger-1 and muscle atrophy F-box genes in the LD muscle were downregulated in the Glu and Arg + Glu groups compared to the basic diet group (P < 0.05). Collectively, these findings suggest that dietary supplementation with both Arg and Glu increases intramuscular FAA concentrations and decreases the mRNA levels of genes involved in protein degradation in skeletal muscle.

Dietary supplementation with arginine and glutamic acid modifies growth performance, carcass traits, and meat quality in growing-finishing pigs.

Sixty Duroc × Large White × Landrace pigs with an average initial BW of 77.1 ± 1.3 kg were used to investigate the effects of dietary supplementation with arginine and glutamic acid on growth performance, carcass traits, and meat quality in growing-finishing pigs. The animals were randomly assigned to 1 of 5 treatment groups (12 pigs/group, male:female ratio 1:1). The pigs in the control group were fed a basal diet (basal diet group), and those in the experimental groups were fed the basal diet supplemented with 2.05% -alanine (isonitrogenous group), 1.0% -arginine (Arg group), 1% glutamic acid + 1.44% -alanine (Glu group), or 1.0% -arginine + 1.0% glutamic acid (Arg+Glu group). After a 60-d period of supplementation, growth performance, carcass traits, and meat quality were evaluated. The results showed no significant differences ( > 0.05) in growth performance and carcass traits of the pigs in the Arg group relative to the basal diet group; however, the longissimus dorsi (LD) muscle and back fat showed a decrease ( < 0.05) in the percentage of SFA. In the Glu group, the final BW, phase 1 (d 1 to 30) and phase 2 (d 31 to 60) ADFI, and average back fat thickness of the pigs decreased ( < 0.05) by 7.14%, 23.43%, 8.03%, and 33.88%, respectively, when compared with the basal diet group. Dietary Arg+Glu supplementation had no effect ( > 0.05) on the final BW, phase 2 ADFI, and average daily weight gain in pigs but decreased ( < 0.05) their phase 1 ADFI, average back fat thickness, and percentage of SFA in the LD muscle and back fat, and increased ( < 0.05) the i.m. fat (IMF) content of the LD and biceps femoris muscles when compared with the basal diet group. Furthermore, a 16% decrease in yellowness (b* value; < 0.05) was observed in the Arg+Glu group pigs when compared with the isonitrogenous group. These findings suggest that dietary supplementation with both Arg and Glu beneficially increases the IMF deposition and improves the meat color and fatty acid composition without affecting growth performance and s.c. fat in pigs, providing a novel strategy to enhance meat quality in growing-finishing pigs.

Short-term supplementation of isocaloric meals with L-tryptophan affects pig growth.

L-Tryptophan (Trp) and some of its metabolites regulate the circadian rhythm in mammals. We aimed to investigate the effects of short-term supplementation of Trp in isocaloric meals on growth performance using the parameters of multiple blood biomarkers and free amino acids in growing pigs. A total of 32 Landrace × Yorkshire barrows with a mean body weight of 8.64 (±1.13) kg were randomly assigned to four groups and then fed with various concentrations of Trp diets daily. Our results showed that sequential supplementation of different concentrations of Trp in isocaloric meals decreased the feed:gain (F:G) ratio (P = 0.079) and plasma urea and albumin (P = 0.019), whereas the level of total protein did not. Among the essential and conditionally essential amino acids, the concentrations of histidine, isoleucine, proline, threonine, arginine, and valine in the plasma decreased (P < 0.05), whereas the concentrations of Trp, glycine, serine, and methionine increased (P < 0.01). In addition, concentrations of branched chain amino acids also significantly decreased (P = 0.004), while the rate of conversion of Trp to branched chain amino acids increased (P < 0.001). Taken together, we show that administration of a high concentration of Trp in breakfast with decreasing concentrations of Trp in lunch and dinner positively affected feed utilization and improved feed efficiency, at least in part, through the optimization of amino acid interconversions and nitrogen utilization.

Dietary supplementation with arginine and glutamic acid enhances key lipogenic gene expression in growing pigs.

Our previous study showed dietary supplementation with Arg and Glu increased intramuscular fat deposition and decreased back fat thickness in pigs, suggesting that the genes involved in lipid metabolism might be regulated differently in muscle and s.c. adipose (SA) tissues. Sixty Duroc × Large White × Landrace pigs with an average initial BW of 77.1 ± 1.3 kg were randomly assigned to 1 of 5 treatment groups (castrated male to female ratio = 1:1). Pigs in the control group were fed a basic diet, and those in experimental groups were fed the basic diet supplemented with 2.05% alanine (isonitrogenous group), 1.00% arginine (Arg group), 1.00% glutamic acid + 1.44% alanine (Glu group), or 1.00% arginine + 1.00% glutamic acid (Arg+Glu group). Fatty acid percentages and mRNA expression levels of the genes involved in lipid metabolism in muscle and SA tissues were examined. The percentages of C14:0 and C16:0 in the SA tissue of Glu group pigs and C14:0 in the longissimus dorsi (LD) muscle of Glu and Arg+Glu groups decreased ( < 0.05) compared to the basic diet group. The Arg+Glu group showed the highest ( < 0.05) hormone-sensitive lipase expression level in SA tissue and higher ( < 0.05) mRNA levels of in the LD muscle than the basic diet and isonitrogenous groups. Additionally, the mRNA level of fatty acid synthase in the Arg+Glu group was more upregulated ( < 0.05) than that of the Arg group. An increase in the mRNA level of in the biceps femoris muscle was also observed in the Arg+Glu group ( < 0.05) compared with the basic diet and isonitrogenous groups. Collectively, these findings suggest that dietary supplementation with Arg and Glu upregulates the expression of genes involved in adipogenesis in muscle tissues and lipolysis in SA tissues.

Dietary supplementation with N-carbamylglutamate increases the expression of intestinal amino acid transporters in weaned Huanjiang mini-pig piglets.

Weaning is associated with reduced intestinal absorptive capacity in piglets. Our previous study indicated that dietary supplementation with N-carbamylglutamate (NCG) enhanced growth performance and improved intestinal function in weaned piglets. The present study was conducted to test the hypothesis that dietary supplementation with NCG may increase the growth performance of weaned piglets by regulating the expression of intestinal nutrient transporters, thus enhancing nutrient absorption. Twenty-four Huanjiang mini-pig piglets weaned at 21 d of age (3.17 ± 0.21 kg average BW) were randomly assigned to 2 dietary treatments consisting of a basal diet and the basal diet with 0.1% NCG supplementation for a 14-d period with 6 pens per treatment and 1 male and 1 female per pen. On d 14, 1 piglet was randomly selected from each pen for blood and tissue sampling. Dietary NCG supplementation enhanced (P < 0.05) growth rate and the efficiency of feed use in weaned Huanjiang mini-pig piglets. The NCG-supplemented diet increased (P < 0.05) mRNA expression levels of Slc6a19, Slc7a9, and Slc1a1 and the protein abundance of ASCT2, B(0)AT1, b(0,+)AT, y(+)LAT1, and EAAC1 in the jejunum. Furthermore, the contents of low density lipoprotein, ammonia, urea nitrogen, and AA as well as the activity of alkaline phosphatase in plasma were all altered (P < 0.05) by supplementation with NCG. These findings indicate that dietary supplementation with NCG may improve intestinal absorptive function in weaned piglets by increasing the expression of AA transporters in the intestine.

Dietary supplementation with Chinese herbal powder enhances ileal digestibilities and serum concentrations of amino acids in young pigs.

This study was designed to determine the effect of ultra-fine Chinese herbal powder as a dietary additive on serum concentrations and apparent ileal digestibilities (AID) of amino acids (AA) in young pigs. In Experiment 1, 60 Duroc x Landrace x Yorkshire piglets weaned at 21 days of age were randomly assigned to one of three treatments, representing supplementation with 0 or 2 g/kg of the powder, or 0.2 g/kg of colistin (an antibiotic) to corn- and soybean meal-based diets (n = 20 per group). Blood samples from five piglets per group were collected on days 7, 14, and 28 to determine serum AA concentrations. In Experiment 2, 12 barrows with an average initial body weight of 7.64 kg were randomly assigned to one of the three dietary treatments, followed by surgical placement of a simple T-cannula at the terminal ileum. All of the diets contained 0.1% titanium oxide as a digestibility marker. The samples of terminal ileal digesta were collected on day 7 for determining AID of AA. Results show that dietary supplementation with the herbal powder increased (P < 0.05) serum concentrations and AID of most AA by 10-50% and 10-16%, respectively. As an indicator of improved intestinal function, AID values of calcium were also enhanced in piglets supplemented with the herbal powder. Dietary supplementation of colistin increased serum concentrations and AID values of some AA by 8-44% and 10-15%, respectively, in comparison with the non-supplemented group. These novel findings demonstrate that the herbal powder can enhance the digestibility of dietary protein and the intestinal absorption of AA into the systemic circulation in post-weaning pigs, therefore providing a new mechanism for its growth- and immunity-promoting efficacy.

Dietary supplementation with Astragalus polysaccharide enhances ileal digestibilities and serum concentrations of amino acids in early weaned piglets.

Two experiments were conducted to evaluate the effects of dietary supplementation with Astragalus polysaccharide (APS) on growth performance, apparent ileal digestibilities (AID) of amino acids (AA), and their serum concentrations in early weaned piglets. In Exp. 1, 60 pigs were weaned at 21 days of age (BW 7.35 +/- 0.23 kg) and allocated to three treatments (20 pigs/treatment), representing supplementing 0.0% (control), 0.02% colistin (antibiotic), or 0.1% APS to a corn- and soybean meal-based diet. Average daily gain (ADG), average daily feed intake (ADFI), and feed/gain ratio (F/G) were measured weekly. Blood samples were obtained from five pigs selected randomly from each treatment for the measurement of serum free AA concentrations on days 7, 14, and 28. In Exp. 2, 12 pigs were weaned at 21 day of age (BW 7.64 +/- 0.71 kg), assigned to three treatment groups as in Exp. 1, and surgically fitted with a simple T-cannula at the terminal ileum. Ileal digesta samples were obtained for the measurement of AID of AA on days 7, 14 and 28. Dietary APS did not affect ADFI, but enhanced (P < 0.05) ADG by 11 and 4.4%, and improved F/G by 5.6 and 8.4%, respectively, compared with the control and antibiotic groups. Addition of APS to the diet increased AID and serum concentrations of most nutritionally essential and non-essential AA (including arginine, proline, glutamate, lysine, methionine, tryptophan, and threonine) on days 14 and 28. Circulating levels of total AA were affected by the age of pigs and treatment x time interaction. Collectively, these findings indicate that APS may ameliorate the digestive and absorptive function and regulate AA metabolism to beneficially increase the entry of dietary AA into the systemic circulation, which provide a mechanism to explain the growth-promoting effect of APS in early weaned piglets.

Immunopotentiating effects of four Chinese herbal polysaccharides administered at vaccination in chickens.

This study was conducted to evaluate the effects of 4 Chinese herbal polysaccharides on the production of serum antibodies and the proliferation of peripheral T lymphocytes, including subpopulations in vaccinated chickens. A total of 450 chickens were randomly assigned to 9 groups at 14 d of age and vaccinated first with live Newcastle disease (ND)-infectious bronchitis virus vaccine, and second with ND-infectious bronchitis oil adjuvant vaccine at 28 d of age. At the same time as the first vaccination, the chickens in groups 1 to 8 were intramuscularly injected with 4 polysaccharides at high and low dosages, respectively, once a day for 3 successive days starting on the day of the first vaccination. Group 9 (control group) was injected in the same manner with saline instead of a polysaccharide. On d 7, 14, 21, 28, 35, 42, and 49 after the first vaccination, the temporal changes in serum ND hemagglutination inhibition antibody titer were determined by the micromethod. On d 10, 20, 30, 40, and 50 after the first vaccination, the proliferation of peripheral blood mononuclear cells in response to concanavalin A stimulation as well as the proportions of CD3(+), CD4(+), and CD8(+) peripheral blood mononuclear cells were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method and flow cytometry, respectively. The results showed that astragalus polysaccharide and isatis root polysaccharide at low dosages, and achyranthes root polysaccharide and Chinese yam polysaccharide at high dosages significantly enhanced the ND antibody titers, concanavalin A-induced proliferation of peripheral blood lymphocytes, and ratio of CD4(+) to CD8(+) (P <0.05). Collectively, these findings indicate that the 4 polysaccharides possess significant immune-enhancing properties in chickens. This finding may have direct application in vaccine design and other strategies designed to potentiate immune system development and function in chickens.

Chinese herbal ingredients are effective immune stimulators for chickens infected with the Newcastle disease virus.

This study was conducted to determine the efficacy of 4 Chinese herbal ingredients (CHI) as immune stimulators for an active vaccine in chickens using both in vitro and in vivo assays. The CHI used were Astragalus polysaccharide (APS), Isatis root polysaccharide (IRPS), Propolis polysaccharide, and Epimedium flavone at various concentrations. Two hundred 14-d-old male White Roman chickens were randomly divided into 10 groups. Chickens in groups 1 to 9 were inoculated with the New-castle disease virus (NDV) strain IV vaccine by intranasal and intraocular administration. Chickens in groups 1 to 8 were also administered subcutaneously on the dorsal region of the neck with 0.5 mL of the corresponding CHI at 2 doses: 29 and 58 mg/kg of BW for APS and IRPS and 7.25 and 14.5 mg/kg of BW for the others, once daily for 3 successive days. In group 9 (CHI-free control) and group 10 (both vaccine- and CHI-free control), chickens were injected with 0.5 mL of physiological saline. New-castle disease virus-specific serum hemagglutination inhibition antibody (Ab) production in immunized chickens was quantified using established methods. The results indicate that a majority of the CHI used at appropriate concentrations were effective in enhancing in vitro proliferation of chick embryo fibroblasts in response to the NDV infection. In vivo administration of CHI to vaccinated chickens (7.25 to 58 mg/kg of BW, depending on type) increased serum anti-NDV hemagglutination inhibition Ab titer concentrations, compared with the administration the NDV alone. For all CHI, a beneficial effect on the Ab production was observed on d 21 after the initiation of the vaccination. On the basis of the in vivo doses used, Propolis polysaccharide and Epimedium flavone were more potent than APS and IRPS in promoting the humoral immune response in the young birds (P < 0.05). Collectively, these findings suggest that appropriate doses of CHI can be used as novel, effective immune stimulators for chickens.

[A study on cultivation techniques for Glycyrrhiza uralensis fisch. in Daxing County area, Beijing].

OBJECTIVE: To study the suitable cultivation techniques for Glycyrrhiza uralensis in the sandy soil in Daxing county area, the Beijing. METHOD: Small plot trial and Large-scale cultivation in the fields. RESULT AND CONCLUSION: Uralensis can be cultivated in the sandy soil in Daxing County area, Beijing.

[Mode of action of parathyroid hormone (PTH) and PTH-related peptide (PTHrP) in target organs]. / Modes d'action de l'hormone parathyroïdienne (PTH) et du peptide apparenté à la PTH (PTHrP) au niveau des organes cibles.

Calcium and phosphorus metabolism is mainly regulated by PTH through its actions on kidney and bone. PTHrP, which is associated with the hypercalcemia of malignancy syndrome, binds to and activates the same receptor that PTH does. cDNA clones of PTH/PTHrP receptors from rat osteosarcoma (ROS 17/2.8) and opossum kidney (OK) cells are highly homologous and are members of a novel G protein-linked receptor family that includes calcitonin, glucagon, GLP-1, GHRH, VIP, and secretin receptors. Analysis of the protein sequence predicts a receptor with 7 transmembrane domains, a 155 amino acids (aa) extracellular (EC) N-terminal, and 130aa intracellular C-terminal domaina. The extracellular domain has 6 conserved cysteines and 4 potential glycosylation sites. When transfected in COS cells, both receptors are able to bind PTH and PTHrP active fragments with equal affinity. Likewise, agonists activate both adenylate cyclase and phospholipase C efficiently. The N-terminal EC domain and the first EC loop seem to determine the receptor binding capacity with the agonists. Activation of adenylate cyclase and phospholipase C might involve multiple sites between the 3rd helix and the C-terminal tail. Partial characterization of the rat PTH/PTHrP receptor gene demonstrates the existence of at least 15 exons. The first six transmembrane domains are encoded by separated exons. The PTH/PTHrP receptor mRNA is expressed mainly in kidney and bone, and also is widely expressed in many tissues, but not all. A major 2.3-2.5 kb transcript is observed in all these tissues. Nevertheless, 2 larger transcripts are observed in kidney and liver, and multiple smaller mRNA species are observed in kidney, skin, and testis.(ABSTRACT TRUNCATED AT 250 WORDS)

A G protein-linked receptor for parathyroid hormone and parathyroid hormone-related peptide.

The complementary DNA encoding a 585-amino acid parathyroid hormone-parathyroid hormone-related peptide (PTH-PTHrP) receptor with seven potential membrane-spanning domains was cloned by COS-7 expression using an opossum kidney cell complementary DNA (cDNA) library. The expressed receptor binds PTH and PTHrP with equal affinity, and both ligands equivalently stimulate adenylate cyclase. Striking homology with the calcitonin receptor and lack of homology with other G protein-linked receptors indicate that receptors for these calcium-regulating hormones are related and represent a new family.