Kyoung-Sik Han

Green kiwifruit modulates the colonic microbiota in growing pigs

Aims:  To investigate whether green kiwifruit modulates the composition of colonic microbiota in growing pigs.

Hydrolyzed casein influences intestinal mucin gene expression in the rat.

The effect of hydrolyzed casein (HC) on the expression of three mucin genes (Muc2, Muc3, and Muc4) in the rat intestine was investigated using quantitative real-time polymerase chain reaction. After a 10 day acclimatization period, rats received for 8 days the test diets containing either HC or a synthetic amino acid (SAA) mixture as the sole source of nitrogen or a protein-free (PF) diet (n = 12 per treatment). The addition of HC or the SAA mixture to the diet significantly improved average daily gain, average daily food intake, and gain:feed ratio as compared with the PF diet. Terminal ileal endogenous N flow was significantly higher for the HC-fed rats in comparison with either the SAA or the PF rats (p < or = 0.001). HC supported a significant increase of Muc3 mRNA (277 and 229% of that for diets PF and SAA, respectively; p < or = 0.05) in the small intestinal tissue and Muc4 mRNA (325 and 265% of that for diets PF and SAA, respectively; p < or = 0.05) in the colon. In conclusion, HC enhances ileal endogenous N flow and up-regulates in vivo the expression of some individual mucin genes.

Orally Administered Ovine Serum Immunoglobulins Influence Growth Performance, Organ Weights, and Gut Morphology in Growing Rats

In this study, our aim was to determine whether orally administered ovine serum Ig improved growth performance, organ weights, and gut morphology in growing rats and whether the method of manufacture of ovine serum Ig affected its bioactivity. Ninety Sprague-Dawley male rats were used in a 21-d growth study and were fed a basal control diet (BD; no Ig) and 5 test diets: spray-dried porcine plasma (SDPP), freeze-dried ovine Ig (FDOI), 2 concentrations of spray-dried ovine Ig (SDOI(100) and SDOI(150)), and inactivated ovine Ig (IOI). Diets were isocaloric and contained the same amount of the first limiting amino acids, methionine plus cysteine. The body weight gain:feed ratio was higher (P < 0.05) for the FDOI-fed rats than for the BD- and IOI-fed groups. FDOI rats had higher jejunum (P < 0.05) and colon weights (P < 0.05) at the end of the study than rats in the BD group. Compared with the SDOI(100)-fed group, the FDOI group supported higher (P < 0.05) duodenum and colon weights. For gut morphology, the FDOI and the BD and IOI groups differed (P < 0.05). The FDOI-fed rats had longer (P < 0.05) villi and greater villi surface areas in the duodenum, jejunum, and ileum than the rats fed SDOI(100). An ovine Ig fraction selectively improved growth performance, organ weight, and gut morphology in growing rats. Compared with spray-drying, a freeze-drying procedure appears to preserve a higher degree of immunological activity.

Green and gold kiwifruit peel ethanol extracts potentiate pentobarbital-induced sleep in mice via a GABAergic mechanism.

Kiwifruit is one of the most popular fruits worldwide, and it has various biological properties, including antioxidant, anti-allergic, and cardiovascular protective effects. The peel of kiwifruit, which is a by-product of processing, is a good source of flavonoids; however, its bioactivity has not been widely investigated. In this study, we evaluated the hypnotic effects of green (GRPE, Actinidia deliciosa) and gold (GOPE, Actinidia chinensis) kiwifruit peel ethanol extracts and their solvent fractions, and the possible underlying mechanisms. Oral GRPE and GOPE administration (125-1000mg/kg) produced a dose-dependent decrease in sleep latency and an increase in sleep duration in pentobarbital-treated mice. Among three different solvent fractions of GRPE and GOPE, ethyl acetate (EA) fractions had the greatest effect on sleep duration at 250mg/kg. The total flavonoid contents of solvent fractions were proportional to sleep duration. Like diazepam (a GABA(A)-benzodiazepine (BZD) receptor agonist), the hypnotic effects of GRPE, GOPE, and their EA fractions were fully inhibited by flumazenil (a GABA(A)-BZD receptor antagonist). These results suggest that potentiation effects of GRPE and GOPE on pentobarbital-induced sleep in mice may be modulated by a GABAergic mechanism.

Ovine Serum Immunoglobulin Has Immunomodulatory Effects in Growing Rats Gavaged with Salmonella enteritidis

In this study, we aimed to determine whether orally administered ovine serum Ig modulate aspects of immunity and associated gut microflora in growing rats challenged with Salmonella enteritidis. The 4 groups consisted of rats fed a casein-based control diet (BD; ungavaged) and 3 groups of rats gavaged with 1 × 10(7) viable Salmonella enteritidis and fed a BD diet, a BD diet containing freeze-dried ovine Ig (FDOI), or a BD diet containing inactivated ovine Ig (IOI). The rats were randomly allocated to 1 of the 4 diets (n = 15) and consumed it for 18 d. They were orally gavaged on d 15. Phagocytic activity of peripheral blood leukocyte and lymphocyte proliferation in the presence of the concanavalin A (ConA) were greater (P < 0.05) in the ungavaged BD- and gavaged FDOI-fed rats than in the gavaged rats fed either the BD or IOI diet. ConA-stimulated Peyers patch cells and splenocytes from the gavaged rats fed the FDOI diet produced more IFNγ, IgA, and IgG than the gavaged rats fed either the BD or IOI diet (P < 0.05). The gavaged FDOI-fed rats had higher ileal and colonic digesta and plasma concentrations of anti-Salmonella secretory sIgA and secretory sIgG (P < 0.05). DNA analysis of a denatured gradient gel electrophoresis profile revealed that 6 of 10 bands had sequence similarity to probiotic strains of bacteria in the ileum and colon of the gavaged FDOI-fed rats. In conclusion, an ovine Ig fraction modulated various indices of immune function and associated gut microflora in growing rats inoculated with Salmonella.

Dietary supplementation with ovine serum immunoglobulin is associated with an increased gut luminal mucin concentration in the growing rat

The mucus layer covering the gut epithelium is pivotal to host defence and is affected by various dietary components. Part of the reported beneficial effect of dietary immunoglobulins (Igs) on gut health may be due to effects on the gut mucus layer. The aim was to determine whether orally administered ovine serum Ig influence goblet cell count, mucin gene expression and digesta mucin protein content in the gut of the growing rat. Fourteen Sprague-Dawley male growing rats were used in a 21-day study and were fed either a casein-based control diet (CON; no Ig) or a similar diet but containing freeze-dried ovine Ig (FDOI). Daily food intake and growth rate were not affected by the dietary treatments. When compared to the rats consuming CON diet, those consuming the FDOI diet had significantly (P < 0.05) more intact and cavitated goblet cells in the intestinal villi. A similar result was found for crypt goblet cells in the small intestine and colon. Ileal Muc2, Muc3, Muc4 and stomach Muc5Ac mRNA expressions for the FDOI animals were higher (P < 0.05) compared to the the CON animals. Mucin protein content was higher (P < 0.05) in the stomach, ileum and colonic digesta of rats fed the FDOI diet. In conclusion, orally administered FDOI influenced gut mucins in the growing rat as evidenced by increased mucin gene expression and digesta mucin protein concentrations as well as an increased goblet cell count.

Comparative analysis of RNA silencing suppression activities between viral suppressors and an endogenous plant RNA-dependent RNA polymerase.

RNA silencing is an evolutionarily conserved system that functions as an antiviral mechanism in eukaryotes, including higher plants. To counteract this, several plant viruses express silencing suppressors that inhibit RNA silencing in host plants. Here, we show that both 2b protein from peanut stunt virus (PSV) and a hairpin construct (designated hp-RDR6) that silences endogenous RNA-dependent RNA polymerase 6 (RDR6) strongly suppress RNA silencing. The Agrobacterium infiltration system was used to demonstrate that both PSV 2b and hp-RDR6 suppressed local RNA silencing as strongly as helper component (HC-Pro) from potato virus Y (PVY) and P19 from tomato bush stunt virus (TBSV). The 2b protein from PSV eliminated the small-interfering RNAs (siRNAs) associated with RNA silencing and prevented systemic silencing, similar to 2b protein from cucumber mosaic virus (CMV). On the other hand, hp-RDR6 suppressed RNA silencing by inhibiting the generation of secondary siRNAs. The small coat protein (SCP) of squash mosaic virus (SqMV) also displayed weak suppression activity of RNA silencing. Agrobacterium-mediated gene transfer was used to investigate whether viral silencing suppressors or hp-RDR6 enhanced accumulations of green fluorescence protein (GFP) and β-glucuronidase (GUS) as markers of expression in leaf tissues of Nicotina benthamiana. Expression of both GFP and GUS was significantly enhanced in the presence of PSV 2b or CMV 2b, compared to no suppression or the weak SqMV SCP suppressor. Co-expression with hp-RDR6 also significantly increased the expression of GFP and GUS to levels similar to those induced by PVY HC-Pro and TBSV P19.

Indian culinary plants enhance glucose-induced insulin secretion and glucose consumption in INS-1 β-cells and 3T3-L1 adipocytes

Six Indian plants, commonly used as culinary plants, herbs or spices (kikar; jamun; neem; harad; fenugreek; bitter gourd), were screened and compared for their antidiabetic potential in vitro. Aqueous plant extracts were prepared and assessed for their effect on the insulin secretion activity of rat pancreatic INS-1 β-cells and glucose consumption in mouse 3T3-L1 adipocytes in order to study their specific mechanisms of action. The effect of the plant extract concentration (25-1000μg/ml) on insulin release and glucose consumption was also studied. All the extracts had a significant stimulatory effect on the insulin secretion of INS-1 cells. In the presence of kikar extract (100μg/ml), an increase of 228% in insulin release was recorded compared to the control (5.6mM glucose) whereas that was 270% and 367% in the presence of kikar and jamun extracts (500μg/ml), respectively. 3T3-L1 cells treated with jamun extract (100μg/ml) exhibited the highest increase in glucose consumption by the cells (94%, compared with the control) followed by harad (53%) and fenugreek (50%) extracts. A significant inhibitory effect of the fenugreek, kikar and jamun extracts on glucose diffusion across a dialysis membrane suggested that these extracts could partly act by decreasing glucose absorption in the small intestine. The results showed that a combination of these plants in diet could help in the management of both type 1 and type 2 diabetes.

Dietary supplementation with ovine serum immunoglobulin attenuates acute effects on growth, organ weights, gut morphology and intestinal mucin production in the growing rat challenged with Salmonella enteritidis.

The aim was to determine the effect of orally administered ovine serum immunoglobulin (Ig) on growth performance, organ weight, gut morphology and mucin production in the Salmonella enteritidis--gavaged growing rat. Four groups consisted of non-gavaged rats fed a casein-based control basal diet (BD) and three groups of rats gavaged with 1×10(7) CFU S. enteritidis and fed a casein-based diet, a diet containing freeze-dried ovine Ig (FDOI) or a casein-based diet containing inactivated ovine Ig (IOI). The rats were randomly allocated to one of the four groups (n=15/group) and received their respective diets for an 18-day experimental study. Gavaging took place on day 15. Average daily gain and body gain : feed ratio (post-gavage, 3 days) were significantly (P<0.05) higher for the Salmonella-challenged rats fed the FDOI diet compared to those fed the BD and IOI diets. At the end of the study, the small intestine and colon were significantly (P<0.05) heavier for the gavaged rats fed the FDOI diet compared to the gavaged rats fed either the BD or IOI diet. Moreover, the relative weights of the caecum, liver and spleen of the gavaged rats fed the BD or IOI diet were significantly (P<0.05) heavier compared to the gavaged rats fed the FDOI diet. Generally, the gavaged rats fed the FDOI diet had significantly (P<0.05) higher goblet cell counts and luminal mucin protein contents than the gavaged rats fed either the BD or IOI diet and had a more functional gut morphology. Overall, the FDOI fraction prevented the acute effects of S. enteritidis.

Recovery of intact IgG in the gastrointestinal tract of the growing rat following ingestion of an ovine serum immunoglobulin.

The aim of this study was to determine whether orally ingested ovine serum IgG partly resists digestion in the growing rat. Fifteen Sprague-Dawley male rats were allocated to one of three diets for a 3-week study: a control diet (CON) and two test diets containing either freeze-dried ovine serum immunoglobulin (FDOI) or inactivated ovine serum immunoglobulin (IOI). Samples of stomach chyme and intestinal digesta from the ad libitum-fed rats were subjected to ELISA and Western blot analysis. Amounts of intact ovine IgG for the FDOI diet were found to be 13.9, 20.0, 34.1, 13.0 and 36.9 μg in the total wet digesta from the stomach chyme, duodenal, jejunal, ileal and colonic digesta respectively. Qualitative detection by Western blot revealed the presence of intact ovine serum IgG with a ~150 kDa MW. This was detected in all of the gut segments (stomach chyme, duodenal, jejunal, ileal and colonic digesta) for growing rats fed the FDOI diet. No ovine IgG was detected in the chyme or digesta from rats fed the CON or the IOI diets. Ovine serum IgG partly resisted digestion in the growing rat fed the FDOI diet and was found throughout the digestive tract. These results provide a basis to explain the reported biological effects of orally administered immunoglobulin.