Effects of neutral phytase on growth performance and phosphorus utilization in crucian carp (<Emphasis Type="Italic">Carassius auratus</Emphasis>)

A feeding trial was conducted for nine weeks to investigate the effects of partially replacing Ca(H₂PO₄)₂ with neutral phytase on the growth performance, phosphorus utilization, nutrient digestibility, serum biochemical parameters, bone and carcass mineral composition, and digestive-enzyme-specific activity in crucian carp (Carassius auratus). The diets prepared with 0.8%, 0%, and 1.8% Ca(H₂PO₄)₂ (1%=1 g/100 g) supplements were regarded as the P₁E₀, negative control (NC), and positive control (PC) groups, respectively; the other three experimental diets were prepared with the addition of 200, 300, and 500 U/kg of neutral phytase, respectively, based on the P₁E₀ group. Three hundred and eighty-four fish ((1.50±0.01) g) were randomly distributed in the six treatments with four replicates each. The fish were initially fed with 2%–3% diets of their body weight per day, with feeding twice daily (08:00 and 16:00), under a 12-h light/12-h dark cycle at the temperature of (27.56±0.89) °C. The results showed that supplemental phytase at different levels in the diet improved the final body weight, average daily gain, feed conversion ratio, phosphorus utilization, and protein efficiency ratio of crucian carp (P<0.05). Phytase supplementation increased the mineral content in serum (P), bone (P, Ca), and carcass (P, Ca, Zn, Na, and Mg) (P<0.05); the trypsin and chymotrypsin activity soared when fed with the phytase-supplemented diets (P<0.05). We may conclude that supplemental dietary neutral phytase improved the growth performance, phosphorus utilization as well as nutrient utilization in crucian carp, and it can be considered an important nutritional replacement for Ca(H₂PO₄)₂.     

Alteration of <Emphasis Type="Italic">SlYABBY2b</Emphasis> gene expression impairs tomato ovary locule number and endogenous gibberellin content

Tomato is an ideal model species for fleshy fruit development research. SlYABBY2b regulates the ovary locule number, which is increased by gibberellins, in tomato. However, the relationship between SlYABBY2b and endogenous gibberellin is poorly understood. In this study, SlYABBY2b-overexpressing and RNA interference (RNAi) transgenic tomato plants were used to elucidate the mechanism by which SlYABBY2b regulates the ovary locule number and endogenous gibberellin content in tomato. SlYABBY2b-overexpressing plants showed fewer locules and lower gibberellin content than the control plants. Contrasting results were found in the RNAi lines. Therefore, the SlYABBY2b gene negatively regulates tomato ovary locule number and endogenous gibberellin content. Furthermore, the expression of SlYABBY2b gene was remarkably higher than that of the wild type in the apical shoots of gibberellindeficient mutants. This showed that the gibberellins can inhibit the expression of SlYABBY2b gene negative regulation. Further study revealed that SlYABBY2b suppressed the expression of SlGA20ox1 and SlGA3ox2, but increased that of SlGA2ox1 and SlGA2ox5 in the apical shoots of SlYABBY2b-overexpressing plants, thereby reducing gibberellin content. Contrasting results were found in the RNAi lines. Our results showed that the SlYABBY2b gene was located on gibberellin signal transduction pathways, fed back regulation of the synthesis of gibberellin, and felt exogenous gibberellin signal to further regulate the formation of tomato locule.     

Influence of low protein diets on gene expression of digestive enzymes and hormone secretion in the gastrointestinal tract of young weaned piglets

To investigate dietary protein level effects on digestive mechanisms, weaned piglets were fed for 45 d with diets containing 20%, 17%, or 14% crude protein (CP) supplemented to meet requirements for essential amino acids. This article describes the influence of dietary protein on gastrointestinal hormones and expression of an array of digestive enzymes in the gastrointestinal tract and pancreas. Results indicated that there were no significant differences in expression of enzymes involved in carbohydrate digestion, except for maltase in the duodenum. In the jejunum, amylase expression in pigs fed 20% CP was much higher than that in pigs fed other diets (P<0.05) and maltase expression in those fed 17% CP was higher than that in other treatments (P<0.05). Although there were no remarkable differences in expression of aminopeptidase in the small intestine or carboxypeptidase in the pancreas (P>0.05), there was a trend towards higher expression of various proteases in pigs fed 17% CP. The duodenal expression of enteropeptidase in diets with 14% and 17% CP was significantly higher than that with 20% CP (P<0.05), but treatment differences did not existed in jejunum (P>0.05). The expression of GPR93 as a nutrient-responsive G protein-coupled receptor in 14% and 17% CP diets was significantly higher than that in 20% CP diet in the small intestine (P<0.05). The expressions of genes for pancreatic enzymes, lipase and elastase, were significantly higher in pigs fed diets with low CP, while similar trends occurred for carboxypeptidase, chymotrypsin and amylase. Conversely, the gastric expressions of pepsinogen A and progastricsin were lower with the 17% CP diet. Differences between treatments were found in the gastric antral contents of cholecystokinin and somatostatin: both increased in pigs fed 17% CP, accompanied by decreased content of motilin, which was also seen in plasma concentrations. These patterns were not reflected in duodenal contents. In general, 17% dietary CP was beneficial to the digestion of nutrient substance in the gastrointestinal tract.     

Spoilage potential of psychrotrophic bacteria isolated from raw milk and the thermo-stability of their enzymes

The storage and transportation of raw milk at low temperatures promote the growth of psychrotrophic bacteria and the production of thermo-stable enzymes, which pose great threats to the quality and shelf-life of dairy products. Though many studies have been carried out on the spoilage potential of psychrotrophic bacteria and the thermo-stabilities of the enzymes they produce, further detailed studies are needed to devise an effective strategy to avoid dairy spoilage. The purpose of this study was to explore the spoilage potential of psychrotrophic bacteria from Chinese raw milk samples at both room temperature (28 °C) and refrigerated temperature (7 °C). Species of Yersinia, Pseudomonas, Serratia, and Chryseobacterium showed high proteolytic activity. The highest proteolytic activity was shown by Yersinia intermedia followed by Pseudomonas fluorescens (d). Lipolytic activity was high in isolates of Acinetobacter, and the highest in Acinetobacter guillouiae. Certain isolates showed positive β-galactosidase and phospholipase activity. Strains belonging to the same species sometimes showed markedly different phenotypic characteristics. Proteases and lipases produced by psychrotrophic bacteria retained activity after heat treatment at 70, 80, or 90 °C, and proteases appeared to be more heat-stable than lipases. For these reasons, thermo-stable spoilage enzymes produced by a high number of psychrotrophic bacterial isolates from raw milk are of major concern to the dairy industry. The results of this study provide valuable data about the spoilage potential of bacterial strains in raw milk and the thermal resistance of the enzymes they produce.     

Effects of dietary fresh fermented soybean meal on growth performance,ammonia and particulate matter emissions,and nitrogen excretion in nursery piglets

This study was conducted to investigate the effects of fresh fermented soybean meal (FSM) on the growth performance of nursery piglets, nitrogen excretion in feces, and the concentrations of ammonia (NH₃) and particulate matter (PM) in the piggery. A total of 472 nursery piglets (Landrace×Yorkshire, (16.3±0.36) kg body weight) were randomly allocated into two treatments with 236 pigs in each treatment. The pigs were fed the basal diet without fresh FSM (control) or diet containing 10% (100 g/kg) fresh FSM (FSM group), and the crude protein content of the two groups was consistent. The feeding trial lasted for 28 d. The results showed that the pigs fed fresh FSM had increased (P<0.05) average daily gain (ADG) compared with the control. There was no significant difference (P>0.05) in feed to gain ratio (F:G) between the two groups. During the whole experiment, the concentration of NH₃ in the piggery decreased (P<0.05) by 19.0%, and the concentrations of PM (PM₁₀ and PM_2.5) in the piggery decreased (P<0.05) by 19.9% and 11.6%, respectively, in the FSM group, compared with the control. The ammonia nitrogen and nitrite content in feces increased (P<0.05) by 32.9% and 28.4%, respectively, in the FSM group. The fecal pH declined (P<0.05) significantly in the FSM group compared with the control. At the end of experiment, total protein (TP) concentration was increased (P<0.05) significantly and blood urea nitrogen (BUN) concentration was decreased (P<0.05) for pigs fed the diet with fresh FSM. The results indicated that dietary fresh FSM not only improved the growth performance of nursery piglets, but also reduced the NH₃ concentration in the piggery due to nitrogen conversion, and decreased the concentrations of PM₁₀ and PM_2.5 in the piggery.     

Biosynthesis of (<Emphasis Type="Italic">R</Emphasis>)-2-hydroxy-3-phenylpropionic acid using whole recombinant <Emphasis Type="Italic">Escherichia coli</Emphasis> cells in an aqueous/<Emphasis Type="Italic">n</Emphasis>-octane biphasic system

(R)-2-hydroxy-3-phenylpropionic acid (PLA) is an ideal antimicrobial compound with broad-spectrum activity against a wide range of Gram-positive bacteria, some Gram-negative bacteria, and fungi. We studied the bioconversion of phenylpyruvate (PPA) to PLA using whole recombinant Escherichia coli cells in a series of buffer/organic solvent systems. Octane was found to be the best organic solvent. The optimum volume ratio of the water phase to the n-octane phase, conversion temperature, substrate concentration, and cell concentration were 6:4, 40 °C, 12.5 g/L, and 30 g/L wet cells, respectively. Under the optimized conditions, the average PLA productivity in the aqueous/n-octane system was 30.69% higher than that in the aqueous system, and 32.31 g/L PLA was obtained with the use of a stirred reactor (2-L scale). Taken together, our findings indicated that PLA biosynthesis was more efficient in an aqueous/n-octane biphasic system than in a monophasic aqueous system. The proposed biphasic system is an effective strategy for enhancing PLA yield and the biosynthesis of its analogues.     

<Emphasis Type="Italic">Chryseobacterium chengduensis</Emphasis> sp. nov. isolated from the air of captive giant panda enclosures in Chengdu,China

A Gram-negative, aerobic, non-motile, rod-shaped bacterial strain, designated 25-1^T, was isolated from the air inside giant panda enclosures at the Chengdu Research Base of Giant Panda Breeding, China. Strain 25-1^T grew optimally at pH 7.0–8.0, at 28–30 °C and in the presence of NaCl concentrations from 0.0% to 0.5 %. 16S rRNA gene sequence analysis indicated that strain 25-1^T belongs to the genus Chryseobacterium within the family Flavobacteriaceae and is related most closely to C. carnis G81^T (96.4% similarity), C. lathyri RBA2-6^T (95.8% similarity), and C. zeae JM1085^T (95.8% similarity). Its genomic DNA G+C molar composition was 36.2%. The major cellular fatty acids were iso-C_15:0 (44.0%), iso-C_17:0 3OH (19.8%) and C_16:1 ω7c/_16:1 ω6c (12.7%). The only isoprenoid quinone was menaquinone 6 (MK-6). The major polar lipids were phosphatidylethanolamine, two unidentified amino lipids and two unidentified lipids. The DNA-DNA relatedness between strain 25-1^T and C. lathyri RBA2-6^T was 38%. Phenotypic, genotypic, and phylogenetic characteristics indicated that strain 25-1^T is a novel member of the genus Chryseobacterium, for which the name C. chengduensis sp. nov. is proposed. The type strain is 25-1^T (CCTCC AB2015133^T=DSM 100396^T).     

A disputed evidence on obesity: comparison of the effects of <Emphasis Type="Italic">Rcan2</Emphasis><Superscript>−/−</Superscript> and <Emphasis Type="Italic">Rps6kb1</Emphasis><Superscript>−/−</Superscript> mutations on growth and body weight in C57BL/6J mice

It is widely accepted that body weight and adipose mass are tightly regulated by homeostatic mechanisms, in which leptin plays a critical role through hypothalamic pathways, and obesity is a result of homeostatic disorder. However, in C57BL/6J mice, we found that Rcan2 increases food intake and plays an important role in the development of age- and diet-induced obesity through a leptin-independent mechanism. RCAN2 was initially identified as a thyroid hormone (T3)-responsive gene in human fibroblasts. Expression of RCAN2 is regulated by T3 through the PI3K-Akt/PKB-mTOR-Rps6kb1 signaling pathway. Intriguingly, both Rcan2^?/? and Rps6kb1^?/? mutations were reported to result in lean phenotypes in mice. In this study we compared the effects of these two mutations on growth and body weight in C57BL/6J mice. We observed reduced body weight and lower fat mass in both Rcan2^?/? and Rps6kb1^?/? mice compared to the wild-type mice, and we reported other differences unique to either the Rcan2^?/? or Rps6kb1^?/? mice. Firstly, loss of Rcan2 does not directly alter body length; however, Rcan2^?/? mice exhibit reduced food intake. In contrast, Rps6kb1^?/? mice exhibit abnormal embryonic development, which leads to smaller body size and reduced food intake in adulthood. Secondly, when fed a normal chow diet, Rcan2^?/? mice weigh significantly more than Rps6kb1^?/? mice, but both Rcan2^?/? and Rps6kb1^?/? mice develop similar amounts of epididymal fat. On a high-fat diet, Rcan2^?/? mice gain body weight and fat mass at slower rates than Rps6kb1^?/? mice. Finally, using the double-knockout mice (Rcan2^?/?Rps6kb1^?/?), we demonstrate that concurrent loss of Rcan2 and Rps6kb1 has an additive effect on body weight reduction in C57BL/6J mice. Our data suggest that Rcan2 and Rps6kb1 mutations both affect growth and body weight of mice, though likely through different mechanisms.     

Supplementation with turmeric residue increased survival of the Chinese soft-shelled turtle (<Emphasis Type="Italic">Pelodiscus sinensis</Emphasis>) under high ambient temperatures

Turmeric residue (TR), containing residual levels of curcumin, is a solid by-product waste generated after the extraction and separation of curcumin from turmeric root. A feeding trial was conducted to evaluate the effects of TR on the survival of Chinese soft-shelled turtles (SSTs), Pelodiscus sinensis, under a high ambient temperature. A total of 320 female SSTs were assigned randomly to two diets: basal diet (the control group, n=160) and an interventional diet supplemented with 10% TR (the TR group, n=160). Our results demonstrated that supplementation of TR increased the SST survival rate by 135.5%, and superoxide dismutase (SOD) activity of SST liver by 112.8%, and decreased the malondialdehyde (MDA) content of SST liver by 36.4%, compared to the control group. The skin of the SST fed TR showed a golden color. High-performance liquid chromatography (HPLC) analysis indicated that the concentrations of curcumin in TR and the skin of the SST fed TR were (1.69±0.30) and (0.14±0.03) μg/g, respectively. Our observation suggests that supplementation of TR increased the survival rate of SST under high ambient temperatures. We speculated that the increased survival rate and tolerance at the high ambient temperature were associated with the anti-oxidation activity of curcumin from TR. Moreover, curcumin in TR could be deposited in SST skin, which made it more favored in the market of China. Our findings provide new knowledge and evidence to effectively reuse TR as a feed additive in animal and aquatic farming.     

Prevalence and genotype of <Emphasis Type="Italic">Chlamydia psittaci</Emphasis> in faecal samples of birds from zoos and pet markets in Kunming,Yunnan, China

Chlamydia psittaci is an important zoonotic pathogen in birds and may be transmitted to humans and result in severe respiratory disease. To assess the prevalence and genotype of C. psittaci in birds in Kunming, Yunnan, China, a total of 136 specimens of psittacine birds involving 8 species were collected from the city’s zoos (n=60) and pet markets (n=76). The frequency of C. psittaci infection was 19.9% (27/136) in the psittacine birds. The prevalence of C. psittaci was higher in pet birds (26.3%; 20/76) than in zoo birds (11.7%; 7/60) (P=0.034). In particular, among Agapornis fischeri, the C. psittaci infection (50%; 10/20) was significantly more frequent in the pet markets than in the zoos (P=0.006). In addition, the highest prevalence of 41.2% (7/17) was found in Ara ararauna. To determine the genotype of C. psittaci, 23 OmpA gene fragments (about 1.4 kb) in 27 positive samples were successfully amplified and sequenced. Phylogenetic analysis showed that all the 23 strains belonged to genotype A. Our results demonstrate the high prevalence of C. psittaci genotype A infection in psittacine birds in Yunnan Province, suggesting a potential threat to human health in this area. Therefore, it is necessary to take effective measures to prevent the spread of C. psittaci among psittacine birds, as well as among employees and customers.     

Response of linear and cyclic electron flux to moderate high temperature and high light stress in tomato

Objectives

To evaluate the possible photoprotection mechanisms of cyclic and linear electron flux (CEF and LEF) under specific high temperature and high light (HH) stress.

Methods

Six-leaf-stage tomato seedlings (“Liaoyuanduoli”, n=160) were divided into four parts: Part 1, served as control under 25 °C, 500 μmol/(m²·s); Part 2, spayed with distilled water (H₂O) under 35 °C, 1000 μmol/(m²·s) (HH); Part 3, spayed with 100 μmol/L diuron (DCMU, CEF inhibitor) under HH; Part 4, spayed with 60 μmol/L methyl viologen (MV, LEF inhibitor) under HH. Energy conversion, photosystem I (PSI), and PSII activity, and trans-thylakoid membrane proton motive force were monitored during the treatment of 5 d and of the recovering 10 d.

Results

HH decreased photochemical reaction dissipation (P) and the maximal photochemical efficiency of PSII (F _v/F _m), and increased the excitation energy distribution coefficient of PSII (β); DCMU and MV aggravated the partition imbalance of the excitation energy (γ) and the photoinhibition degree. With prolonged DCMU treatment time, electron transport rate and quantum efficiency of PSI (ETR_I and Y _I) significantly decreased whereas acceptor and donor side limitation of PSI (Y _NA and Y _ND) increased. MV led to a significant decline and accession of yield of regulated and non-regulated energy Y _NPQ and Y _NO, respectively. Membrane integrity and ATPase activity were reduced by HH stress, and DCMU and MV enhanced inhibitory actions.

Conclusion

The protective effects of CEF and LEF were mediated to a certain degree by meliorations in energy absorption and distribution as well as by maintenance of thylakoid membrane integrity and ATPase activity.

     

Low-Temperature Selective Catalytic Reduction of NO with NH<Subscript>3</Subscript> over Fe–Ce–O<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> Catalysts

In this study, we used a simple impregnation method to prepare Fe–Ce–O _x catalysts and tested them regarding their low-temperature (200–300 °C) selective catalytic reduction (SCR) of NO using NH₃. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO₂/H₂O resistance of the catalysts. The results showed that the FeCe(1:6)O _x (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O _x catalyst had the highest NO conversion with an activity of 94–99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h^?1. The NO conversion for the FeCe(1:6)O _x catalyst also reached 80–98% between 200 and 300 °C at a space velocity of 204,000 h^?1. In addition, the FeCe(1:6)O _x catalyst demonstrated good stability in a 10-h SCR reaction at 200–300 °C. Even in the presence of SO₂ and H₂O, the FeCe(1:6)O _x catalyst exhibited good SCR performance.     

Ultrasound extraction optimization,structural features,and antioxidant activity of polysaccharides from <Emphasis Type="Italic">Tricholoma matsutake</Emphasis>

An ultrasonic-assisted technique was employed to extract crude polysaccharide from Tricholoma matsutake fruiting bodies. Single-factor tests and orthogonal experimental design (L ₉(3³)) were used to obtain the optimal extraction conditions. Results showed that the optimal parameters were as follows: ultrasonic temperature, 40 °C; ultrasonic time, 50 min; water to raw material ratio, 25 ml/g; ultrasonic frequency, 45 kHz; and ultrasonic power, 100 W. Three novel T. matsutake polysaccharide (TMP) fractions (TMP30, TMP60, and TMP80) were isolated and purified from TMP by stepwise alcohol precipitation. Their preliminary structural features were determined by high-performance anion-exchange chromatography with pulsed-amperometric detection (HPAEC-PAD) and Fourier transform infrared spectrophotometer (FT-IR) analyses. Furthermore, their in vitro antioxidant activity was investigated in terms of a reducing power assay and the scavenging rates of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. The order of the various fractions based on their antioxidant activity was TMP80>TMP>TMP60>TMP30. These findings suggested that novel polysaccharide fractions from T. matsutake, especially TMP80, could be promising active macromolecules for biomedical use.     

Biomolecular characterization,identification, enzyme activities of molds and physiological changes in sweet potatoes (<Emphasis Type="Italic">Ipomea batatas</Emphasis>) stored under controlled atmospheric conditions

Microbial attacks during storage are one of the primary causes of product deterioration, and can limit the process of prolonging the shelf-life of harvested food. In this study, sweet potatoes were stored at temperatures of 13, 21, and 29 °C for 4 weeks. Samples were collected during storage and plated on potato dextrose agar, from which axenic mold cultures were obtained and identified using 26S rRNA gene sequences. Physiological changes of potato tubers were assessed with respect to pathogenicity, enzyme activity, and atmospheric storage conditions. Six fungal species were identified, namely Penicillium chrysogenum (P. rubens), P. brevicompactum, Mucor circinelloides, Cladosporium cladosporiodes, P. expansum, and P. crustosum. The following fungal isolates, namely P. expansum, P. brevicompactum, and Rhizopus oryzae, were recovered from the re-infected samples and selected according to their levels of enzyme activity. This study revealed high levels of activity for cellulase and pectinase, which were most notable during the initial three days of testing, and were followed by a steady decrease (P<0.05). Polygalacturonase activity was prominent with values ranging from 12.64 to 56.79 U/mg (P. expansum) and 18.36 to 79.01 U/mg (P. brevicompactum). Spoilage was obvious in the control group, which had a 100% decay at the end of the experimental period compared with samples treated with iprodione and sodium hypochlorite, in which the decay rates were 5% and 55%, respectively. The data for the iprodione- and sodium hypochlorite-treated samples at the end of the 3-month storage period showed that they were significantly different (P=0.041), with the sodium hypochlorite-treated samples producing twice the rate of infection compared to the iprodione-treated samples. The comparative rate of the progression of decay in the treated samples can be expressed as iprodione<sodium hypochlorite<control. This study demonstrates that sweet potato tissue damage is due to the activities of microbial enzymes and, in particular, the pectinases of the organisms isolated from the infected potato tissues, and suggests the advantages of utilizing iprodione as a curing agent for potato tubers before storage.     

Characterization of β-glucosidase from <Emphasis Type="Italic">Aspergillus terreus</Emphasis> and its application in the hydrolysis of soybean isoflavones

An extracellular β-glucosidase produced by Aspergillus terreus was identified, purified, characterized and was tested for the hydrolysis of soybean isoflavone. Matrix-assisted laser desorption/ionization with tandem time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) revealed the protein to be a member of the glycosyl hydrolase family 3 with an apparent molecular mass of about 120 kDa. The purified β-glucosidase showed optimal activity at pH 5.0 and 65 °C and was very stable at 50 °C. Moreover, the enzyme exhibited good stability over pH 3.0–8.0 and possessed high tolerance towards pepsin and trypsin. The kinetic parameters K_m (apparent Michaelis-Menten constant) and V_max (maximal reaction velocity) for p-nitrophenyl-β-d-glucopyranoside (pNPG) were 1.73 mmol/L and 42.37 U/mg, respectively. The K_m and V_max for cellobiose were 4.11 mmol/L and 5.7 U/mg, respectively. The enzyme efficiently converted isoflavone glycosides to aglycones, with a hydrolysis rate of 95.8% for daidzin, 86.7% for genistin, and 72.1% for glycitin. Meanwhile, the productivities were 1.14 mmol/(L·h) for daidzein, 0.72 mmol/(L·h) for genistein, and 0.19 mmol/(L·h) for glycitein. This is the first report on the application of A. terreus β-glucosidase for converting isoflavone glycosides to their aglycones in soybean products.     

A high-fat diet increases body fat mass and up-regulates expression of genes related to adipogenesis and inflammation in a genetically lean pig

Because of their physiological similarity to humans, pigs provide an excellent model for the study of obesity. This study evaluated diet-induced adiposity in genetically lean pigs and found that body weight and energy intake did not differ between controls and pigs fed the high-fat (HF) diet for three months. However, fat mass percentage, adipocyte size, concentrations of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), insulin, and leptin in plasma were significantly higher in HF pigs than in controls. The HF diet increased the expression in backfat tissue of genes responsible for cholesterol synthesis such as Insig-1 and Insig-2. Lipid metabolism-related genes including sterol regulatory element binding protein 1c (SREBP-1c), fatty acid synthase 1 (FASN1), diacylglycerol O-acyltransferase 2 (DGAT2), and fatty acid binding protein 4 (FABP4) were significantly up-regulated in backfat tissue, while the expression of proliferator-activated receptor-α (PPAR-α) and carnitine palmitoyl transferase 2 (CPT2), both involved in fatty acid oxidation, was reduced. In liver tissue, HF feeding significantly elevated the expression of SREBP-1c, FASN1, DGAT2, and hepatocyte nuclear factor-4α (HNF-4α) mRNAs. Microarray analysis further showed that the HF diet had a significant effect on the expression of 576 genes. Among these, 108 genes were related to 21 pathways, with 20 genes involved in adiposity deposition and 26 related to immune response. Our results suggest that an HF diet can induce genetically lean pigs into obesity with body fat mass expansion and adipose-related inflammation.     

Probiotic properties of lactic acid bacteria isolated from traditionally fermented Xinjiang cheese

Six lactic acid bacterial (LAB) strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strains comprised Lactobacillus rhamnosus (one strain), Lactobacillus helveticus (one strain), and Enterococcus hirae (four strains). All of the six strains were tolerant to acidic and bile salt conditions. Among which, the L. rhamnosus R4 strain showed more desirable antimicrobial, auto-aggregation, and hydrophobic activity. In addition, the strain L. rhamnosus R4 exhibited the highest level of free radical scavenging activity (53.78% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and 45.79% of hydroxyl radicals). L. rhamnosus R4 also demonstrated cholesterol and triglyceride degradation by 50.97% and 28.92%, respectively. To further examine the health-promoting effects of these LAB strains on host lifespan, Caenorhabditis elegans was used as an in vivo model. Worms fed LAB as a food source had significant differences in lifespan compared to those fed Escherichia coli OP50 (as a negative control). Feeding of L. rhamnosus R4 extended the mean lifespan of C. elegans by up to 36.1% compared to that of the control. The results suggest that the strains isolated from Xinjiang fermented dairy products have high potential as starter cultures in the cheese industry.