Effect of manganese source on manganese absorption and expression of related transporters in the small intestine of broilers.

An experiment was conducted to investigate the effect of manganese (Mn) source on Mn absorption and expressions of Mn, amino acid, and peptide transporters in the small intestine of broilers. A total of 320 Mn-deficient 15-day-old Arbor Acres male broilers were randomly assigned to 5 treatments with 8 replicates/treatment and 8 chicks/replicate and fed an Mn-unsupplemented control diet or the control diet supplemented with 110 mg Mn/kg from either MnSO4, or 1 of 3 organic Mn chelates with weak (OW), moderate (OM), or strong (OS) chelation strength for 14 D. The plasma Mn contents were higher (P < 0.03) in supplemental Mn groups than in the control group, in OS group than in OM group, and in OM group than in OW and MnSO4 groups on day 28. Broilers fed diets supplemented with Mn had higher (P < 0.02) duodenal divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) mRNA levels and FPN1 protein level on both days 21 and 28 than those fed the control diet. Duodenal DMT1 mRNA and protein levels were higher (P < 0.05) in OM and OS groups than in OW and MnSO4 groups on day 28. The mRNA levels of amino acid transporters [b0, +-type amino acid transporter 1 (B0AT1) and excitatory amino acid transporter 3 (EAAT3)] were higher (P < 0.0005), and peptide transporter 1 was lower (P < 0.04) in the ileum than in the duodenum and jejunum; however, Mn source did not affect (P > 0.05) mRNA levels of amino acid and peptide transporters in the small intestine of broilers. The results from the present study indicate that both DMT1 and FPN1 facilitated Mn absorption, however, the amino acid and peptide transporters might not be involved in the transport of the organic Mn chelates; organic Mn chelates with moderate and strong chelation strength, especially strong chelation strength, showed higher Mn absorption possibly due to enhanced DMT1 expression in the duodenum of broilers.

Dietary supplementation of organic or inorganic chromium modulates the immune responses of broilers vaccinated with Avian Influenza virus vaccine.

Dietary supplementation with the organic chromium (Cr) has been shown to positively affect the immune function of poultry. However, to our knowledge, no experiment has been done to directly compare the impacts of Cr chloride and chromium picolinate (CrPic) on the immune responses of broilers vaccinated with Avian Influenza (AI) virus vaccine. Therefore, the present experiment was conducted to investigate the effects of supplemental Cr sources (Cr chloride and CrPic) and levels on the growth performance and immune responses of broilers vaccinated with AI virus vaccine so as to provide an effective nutritional strategy for improving immune function of broilers. A total of 432 1-day (d)-old male broiler chicks were used in a 1 plus 2×4 design. Chickens were given either a diet without Cr supplementation (control) or diets supplemented with 0.4, 0.8, 1.6, or 3.2 mg Cr/kg as either Cr chloride or CrPic for 42 d. Compared to the control, dietary Cr supplementation had no effect (P>0.05) on average daily gain, average daily feed intake and gain : feed of broilers during the starter and grower phases, but increased (P<0.05) the relative weights of bursa of fabricius on d 21 and thymus, spleen, or bursa of fabricius on d 42, serum antibody titers against AI virus on d 21, 28, 35 and 42, blood T-lymphocyte transformation rate on d 28 and 42, blood T-lymphocyte percentage on d 42, and serum interleukin-2 contents on d 28. Broilers fed the diets supplemented with the inorganic Cr chloride had higher (P<0.05) weights of thymus, spleen and bursa of fabricius than those fed the diets supplemented with the CrPic on d 42. In addition, broilers fed the diets supplemented with the CrPic had higher (P<0.05) antibody titers against AI virus than those fed the diets supplemented with the inorganic Cr chloride on d 21 and 35. These results indicate that dietary Cr supplementation improved immune responses of broilers vaccinated with AI virus, and the inorganic Cr chloride was more effective than the CrPic in increasing the relative weights of lymphoid organs, however, the CrPic was more effective than the inorganic Cr chloride in enhancing the serum antibody titer against AI virus.

Effects of fermented soybean meal on carbon and nitrogen metabolisms in large intestine of piglets.

Fermented soybean meal (FSM), which has lower anti-nutritional factors and higher active enzyme, probiotic and oligosaccharide contents than its unfermented form, has been reported to improve the feeding value of soybean meal, and hence, the growth performance of piglets. However, whether FSM can affect the bacterial and metabolites in the large intestine of piglets remains unknown. This study supplemented wet-FSM (WFSM) or dry-FSM (DFSM) (5% dry matter basis) in the diet of piglets and investigated its effects on carbon and nitrogen metabolism in the piglets' large intestines. A total of 75 41-day-old Duroc×Landrace×Yorkshire piglets with an initial BW of 13.14±0.22 kg were used in a 4-week feeding trial. Our results showed that the average daily gain of piglets in the WFSM and DFSM groups increased by 27.08% and 14.58% and that the feed conversion ratio improved by 18.18% and 7.27%, respectively, compared with the control group. Data from the prediction gene function of Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) based on 16S ribosomal RNA (rRNA) sequencing showed that carbohydrate metabolism function families in the WFSM and DFSM groups increased by 3.46% and 2.68% and that the amino acid metabolism function families decreased by 1.74% and 0.82%, respectively, compared with the control group. These results were consistent with those of other metabolism studies, which showed that dietary supplementation with WFSM and DFSM increased the level of carbohydrate-related metabolites (e.g. 4-aminobutanoate, 5-aminopentanoate, lactic acid, mannitol, threitol and ß-alanine) and decreased the levels of those related to protein catabolism (e.g. 1,3-diaminopropane, creatine, glycine and inosine). In conclusion, supplementation with the two forms of FSM improved growth performance, increased metabolites of carbohydrate and reduced metabolites of protein in the large intestine of piglets, and WFSM exhibited a stronger effect than DFSM.

Mode of action of Saccharomyces cerevisiae in enteric methane mitigation in pigs.

The objectives of this study were to determine the effect and mode of action of Saccharomyces cerevisiae (YST2) on enteric methane (CH4) mitigation in pigs. A total of 12 Duroc×Landrace×Yorkshire male finisher pigs (60±1 kg), housed individually in open-circuit respiration chambers, were randomly assigned to two dietary groups: a basal diet (control); and a basal diet supplemented with 3 g/YST2 (1.8×1010 live cells/g) per kg diet. At the end of 32-day experiment, pigs were sacrificed and redox potential (Eh), pH, volatile fatty acid concentration, densities of methanogens and acetogens, and expression of methyl coenzyme-M reductase subunit A gene were determined in digesta contents from the cecum, colon and rectum. Results showed that S. cerevisiae YST2 decreased (P<0.05) the average daily enteric CH4 production by 25.3%, lowered the pH value from 6.99 to 6.69 in the rectum, and increased the Eh value in cecum and colon by up to -55 mV (P<0.05). Fermentation patterns were also altered by supplementation of YST2 as reflected by the lower acetate, and higher propionate molar proportion in the cecum and colon (P<0.05), resulting in lower acetate : propionate ratio (P<0.05). Moreover, there was a 61% decrease in Methanobrevibacter species in the upper colon (P<0.05) and a 19% increase in the acetogen community in the cecum (P<0.05) of treated pigs. Results of our study concluded that supplementation of S. cerevisiae YST2 at 3 g/kg substantially decreased enteric CH4 production in pigs.

Effect of iron source on iron absorption and gene expression of iron transporters in the ligated duodenal loops of broilers.

This experiment was conducted to investigate the effect of iron source on Fe absorption and the gene expression of divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) in the ligated duodenal loops of broilers. The in situ ligated duodenal loops from Fe-deficient broiler chicks (28-d-old) were perfused with Fe solutions containing 0 to 14.33 mmol Fe/L from 1 of the following: Fe sulfate (FeSO∙7HO), Fe methionine with weak chelation strength (Fe-Met W; chelation strength is expressed as quotient of formation [Q] value, Q = 1.37), Fe proteinate with moderate chelation strength (Fe-Prot M; Q = 43.6), and Fe proteinate with extremely strong chelation strength (Fe-Prot ES; Q = 8,590) for up to 30 min. The gene expression of DMT1 and FPN1 in the duodenal loops from the control group and the groups treated with 3.58 mmol Fe/L from 1 of 4 Fe sources was analyzed. The absorption kinetics of Fe from different Fe sources in the duodenum followed a saturated carrier-dependent transport process. The maximum transport rate (J) values in the duodenum were greater ( < 0.03) for Fe-Prot ES and Fe-Prot M than for Fe-Met W and FeSO∙7HO. The Fe perfusion inhibited ( < 0.05) the mRNA expression of but enhanced ( < 0.0008) the mRNA expression of in the duodenum and had no effect ( > 0.14) on the protein expression levels of the 2 transporters. These results indicated that organic Fe sources with greater Q values showed higher Fe absorption; however, all Fe sources followed the same saturated carrier-dependent transport process in the duodenum, and DMT1 and FPN1 might participate in Fe absorption in the duodenum of broilers regardless of Fe source.

Effects of sodium, 1,25-dihydroxyvitamin D3 and parathyroid hormone fragment on inorganic P absorption and Type IIb sodium-phosphate cotransporter expression in ligated duodenal loops of broilers.

Three experiments were conducted with 22-day-old Arbor Acres male broilers to study the effects of Na+, 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and parathyroid hormone fragment [PTH (1-34)] on inorganic P absorption and Type IIb sodium-phosphate cotransporter (NaP-IIb) mRNA and protein expression levels in ligated duodenal loops. The duodenal loops were perfused with solutions (pH = 6) containing zero, 50, or 150 mmol/L of Na+ as NaCl in Exp. 1, containing zero, 30, or 300 pmol/L of 1,25-(OH)2D3 in Exp. 2, or containing zero, 65, or 650 pmol/L of PTH (1-34) in Exp. 3, respectively. Compared with the control, additions of 50 and 150 mmol/L of Na+, 30 and 300 pmol/L of 1,25-(OH)2D3, or 65 and 650 pmol/L of PTH (1-34) to the perfusates promoted (P < 0.02) the P absorption percentages and rates, respectively. Additions of the above-mentioned concentrations of Na+ or 1,25-(OH)2D3 to the perfusates increased (P < 0.003) NaP-IIb mRNA level in the duodenum of broilers, and a similar trend (P = 0.08) was observed for PTH (1-34). The Na+, 1,25-(OH)2D3, and PTH (1-34) had no effects (P > 0.15) on NaP-IIb protein level in the duodenum of broilers. The results indicate that increased P absorption due to perfusions of Na+, 1,25-(OH)2D3 or PTH (1-34) might be attributed to enhanced NaP-IIb expression in the duodenum of broilers.

Dietary non-phytate phosphorus requirement of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age.

An experiment was conducted to investigate the effect of dietary non-phytate phosphorus (NPP) level on growth performance, bone characteristics and phosphorus metabolism-related gene expressions, so as to evaluate the dietary NPP requirement of broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age. A total of 540 day-old Arbor Acres male chicks were randomly allocated to one of nine treatments with six replicate cages of 10 birds per cage in a completely randomized design, and fed a basal corn-soybean meal diet (containing 0.08% of NPP) supplemented with 0.10, 0.15, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50% of inorganic phosphorus in the form of CaHPO4·2H2O, respectively. Each diet contained the constant calcium content of about 1.0%. The results showed that daily weight gain, serum inorganic P, tibia bone strength, tibia ash percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage, middle toe BMC and BMD were affected (P < 0.0001) by dietary NPP level, and increased linearly (P < 0.0001) and quadraticly (P < 0.004) as dietary NPP levels increased. The gene expression of type IIb sodium-phosphate cotransporter (NaPi-IIb) in the duodenum was affected (P < 0.03) and decreased linearly (P < 0.002) as dietary NPP levels increased. Dietary NPP requirements estimated based on fitted broken-line models (P < 0.0001) of the sensitive indices including daily weight gain, tibia bone strength, tibia ash percentage, tibia BMC and BMD as well as middle toe ash percentage were 0.34∼0.39%. The results from this study indicate that tibia BMC and BMD might be new, sensitive, and noninvasive criteria to evaluate the dietary NPP requirements of broilers, and the dietary NPP requirement is 0.39% for broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age.

Kinetics of phosphorus absorption in ligated small intestinal segments of broilers.

Two experiments were conducted using 22-d-old Arbor Acres male broilers to study the kinetics of inorganic P absorption and the effect of P treatment on Type IIb sodium-phosphate cotransporter (NaP-IIb) mRNA and protein levels in ligated segments from different intestinal regions. In Exp. 1, the P absorption in different small intestinal segments at different postperfusion times (0, 2.5, 5, 10, 20, or 40 min) were compared. In Exp. 2, different small intestinal loops were perfused with solutions containing 0, 1.5, 3, 6, 12, 24, or 48 mmol P/L as KHPO, and P concentrations in perfusates were determined at 20 min after perfusion. The mRNA levels of NaP-IIb in different small intestinal loops and protein expression levels in the duodenums from the control group and the 6 or 48 mmol P/L group were analyzed. The results from Exp. 1 showed that P absorption increased in an asymptotic response to postperfusion time within 40 min in all the intestinal segments and P absorption was greater ( < 0.04) in the duodenum than in the other 2 segments at 20 min after perfusion, indicating that the duodenum is the main site of P absorption in the small intestine of chicks. In Exp. 2, the kinetic curves showed that P absorption in the duodenum was a saturated carrier mediated process and in the jejunum or ileum occurred with a nonsaturated diffusion process. In addition, the b mRNA levels were greater ( < 0.0001) in the duodenum than in the other 2 segments in the 3 groups (0, 6, or 48 mmol P/L), further indicating that P absorption in the duodenum occurred mainly by a saturated carrier mediated process. However, no significant differences ( = 0.20) in the NaP-IIb protein levels of the duodenum were observed among the 0, 6, and 48 mmol P/L groups. In conclusion, this study suggests by our criteria in ligated intestinal loops that the duodenum is the main site of P absorption and that P absorption may be a saturated carrier mediated process in the duodenum but a nonsaturated diffusion process in the jejunum or ileum of broilers.

Effect of dietary fiber on the methanogen community in the hindgut of Lantang gilts.

The primary objective of this study was to investigate the effect of dietary fiber on methanogenic diversity and community composition in the hindgut of indigenous Chinese Lantang gilts to explain the unexpected findings reported earlier that Lantang gilts fed low-fiber diet (LFD) produced more methane than those fed high-fiber diet (HFD). In total, 12 Lantang gilts (58.7±0.37 kg) were randomly divided into two dietary groups (six replicates (pigs) per group) and fed either LFD (NDF=201.46 g/kg) or HFD (NDF=329.70 g/kg). Wheat bran was the main source of fiber for the LFD, whereas ground rice hull (mixture of rice hull and rice bran) was used for the HFD. Results showed that the methanogens in the hindgut of Lantang gilts belonged to four known species (Methanobrevibacter ruminantium, Methanobrevibacter wolinii, Methanosphaera stadtmanae and Methanobrevibacter smithii), with about 89% of the methanogens belonging to the genus Methanobrevibacter. The 16S ribosomal RNA (rRNA) gene copies of Methanobrevibacter were more than three times higher (P0.05) was observed in 16S rRNA gene copies of Fibrobacter succinogenes between the two dietary groups, and 18S rRNA gene copies of anaerobic fungi in gilts fed LFD were lower than (P<0.05) those fed HFD. To better explain the effect of different fiber source on the methanogen community, a follow-up in vitro fermentation using a factorial design comprised of two inocula (prepared from hindgut content of gilts fed two diets differing in their dietary fiber)×four substrates (LFD, HFD, wheat bran, ground rice hull) was conducted. Results of the in vitro fermentation confirmed that the predominant methanogens belonged to the genus of Methanobrevibacter, and about 23% methanogens was found to be distantly related (90%) to Thermogymnomonas acidicola. In vitro fermentation also seems to suggest that fiber source did change the methanogens community. Although the density of Methanobrevibacter species was positively correlated with CH4 production in both in vivo (P<0.01, r=0.737) and in vitro trials (P<0.05, r=0.854), which could partly explain the higher methane production from gilts fed LFD compared with those in the HFD group. Further investigation is needed to explain how the rice hull affected the methanogens and inhibited CH4 emission from gilts fed HFD.

Kinetics of iron absorption by in situ ligated small intestinal loops of broilers involved in iron transporters.

Two experiments were conducted with 28-d-old commercial male broilers to study the kinetics of iron (Fe) absorption and the effect of Fe treatment on divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) mRNA levels in in situ ligated segments from different small intestinal regions of broilers. In Exp. 1, we compared Fe absorption in 3 small intestinal segments at different post-perfusion time points after perfusion with 0.45 m of Fe as Fe sulfate (FeSO ∙ 7HO), and found that the Fe absorption in the duodenum at 30, 45, and 60 min was greater ( < 0.006) than that in the jejunum, and at 60 min, the Fe absorption in the duodenum was greater ( = 0.034) than that in the ileum. In addition, the Fe absorption at 30 min was more than 85.0% of the maximum absorption in each segment. In Exp. 2, a kinetic study of Fe absorption was performed with the duodenal, jejunal, and ileal loops perfused with solutions containing 0 (control), 0.11, 0.22, 0.45, 0.80, 1.79, or 3.58 m of Fe as FeSO 7HO. The Fe concentrations in perfusates were measured at 30 min after perfusion, and in the control group and the group treated with 0.45 m Fe as FeSO 7HO, the DMT1 and FPN1 mRNA levels in the ligated duodenum, jejunum, and ileum were analyzed. The kinetic curves of Fe absorption showed that Fe absorption in the duodenum and jejunum depended on a saturated carrier-mediated process. The maximum absorption rate in the duodenal segment was greater ( < 0.0001) than that in the jejunum (42.75 vs. 8.16 nmol × cm × min), and the Michaelis-Menten constant value was higher ( < 0.0001) in the duodenum than in the jejunum (6.16 vs. 1.31 m). In the ileum, however, the Fe absorption was a non-saturated diffusion process, and the diffusive constant was 3.54 × 10 cm × min. The DMT1 and FPN1 mRNA levels in the duodenum were greater ( < 0.0001) than those in the jejunum and ileum, and greater ( < 0.009) in the jejunum than in the ileum. No differences ( > 0.25) were detected in the DMT1 and FPN1 mRNA levels of the duodenum or jejunum and the DMT1 mRNA level of the ileum between the control and the 0.45 m Fe group, but Fe perfusion increased ( < 0.03) FPN1 mRNA level in the ileum. The above results indicate that the duodenum is the main site of Fe absorption in the small intestine of broilers, and Fe absorption in the duodenum and jejunum is a saturated carrier-mediated process, but a non-saturated diffusion process in the ileum.

Effects of Clostridium butyricum on growth performance, antioxidation, and immune function of broilers.

To investigate the effects of Clostridium butyricum on growth performance, antioxidation, and immune function of broilers, 320 one-day-old Arbor Acres commercial male chicks were assigned to one of 5 treatments with 8 replicates in a completely randomized design for 42 d. The 5 treatments were basal diet (control), basal diet supplemented with 2.5×10(8) cfu C. butyricum/kg (CB1), basal diet supplemented with 5×10(8) cfu C. butyricum/kg (CB2), basal diet supplemented with 1×10(9) cfu C. butyricum/kg (CB3), and basal diet supplemented with 150 mg aureomycin/kg (antibiotic). The results showed that all C. butyricum-supplemented groups during d 1 to 21 and the CB2 group during d 22 to 42 had higher ADG compared with the control (P<0.05). Chicks fed the CB3 diet had higher glutathione S-transferase (GST) activity (P<0.05), and chicks fed the CB2 diet had a higher glutathione (GSH) concentration in duodenal and ileal mucosa at 21 d of age than those in the control group (P<0.05). Chicks fed the CB3 diet had a lower malondialdehyde (MDA) concentration in duodenal mucosa than those in the control and CB1 groups (P<0.05). Chicks fed the CB2, CB3, and antibiotic diets had a lower MDA concentration in ileal mucosa than those in the control and CB1 groups (P<0.05). Broilers fed the CB3 diet had greater superoxide dismutase (SOD) activity in the ileal mucosa on d 21 and in jejunal mucosa on d 42 than those in the other groups (P<0.05). Chicks fed the CB2, CB3, and antibiotic diets had a higher GSH concentration in duodenal and jejunal mucosa on d 42 than those in the control group (P<0.05). Broilers fed the CB2 and CB3 diets had a lower MDA concentration in the jejunal mucosa on d 42 than those in the control and CB1 groups. Chicks fed diets supplemented with C. butyricum had a higher IgM concentration than those in the control group at 21 and 42 d of age (P<0.05). The results indicate that C. butyricum improves broilers' growth performance, antioxidation, and immune function.

Saccharomyces cerevisiae Live Cells Decreased In vitro Methane Production in Intestinal Content of Pigs.

An in vitro gas production technique was used in this study to elucidate the effect of two strains of active live yeast on methane (CH4) production in the large intestinal content of pigs to provide an insight to whether active live yeast could suppress CH4 production in the hindgut of pigs. Treatments used in this study include blank (no substrate and no live yeast cells), control (no live yeast cells) and yeast (YST) supplementation groups (supplemented with live yeast cells, YST1 or YST2). The yeast cultures contained 1.8×10(10) cells per g, which were added at the rates of 0.2 mg and 0.4 mg per ml of the fermented inoculum. Large intestinal contents were collected from 2 Duroc×Landrace×Yorkshire pigs, mixed with a phosphate buffer (1:2), and incubated anaerobically at 39°C for 24 h using 500 mg substrate (dry matter (DM) basis). Total gas and CH4 production decreased (p<0.05) with supplementation of yeast. The methane production reduction potential (MRP) was calculated by assuming net methane concentration for the control as 100%. The MRP of yeast 2 was more than 25%. Compared with the control group, in vitro DM digestibility (IVDMD) and total volatile fatty acids (VFA) concentration increased (p<0.05) in 0.4 mg/ml YST1 and 0.2 mg/ml YST2 supplementation groups. Proportion of propionate, butyrate and valerate increased (p<0.05), but that of acetate decreased (p<0.05), which led to a decreased (p<0.05) acetate: propionate (A: P) ratio in the both YST2 treatments and the 0.4 mg/ml YST 1 supplementation groups. Hydrogen recovery decreased (p<0.05) with yeast supplementation. Quantity of methanogenic archaea per milliliter of inoculum decreased (p<0.05) with yeast supplementation after 24 h of incubation. Our results suggest that live yeast cells suppressed in vitro CH4 production when inoculated into the large intestinal contents of pigs and shifted the fermentation pattern to favor propionate production together with an increased population of acetogenic bacteria, both of which serve as a competitive pathway for the available H2 resulting in the reduction of methanogenic archaea.

Co-composting of soybean residues and leaves in Hong Kong.

The goal of this project was to evaluate the feasibility of co-composting of soybean residues and leaves and the effects of turning frequency on compost quality. Soybean residues were mixed with leaves and sawdust in 1:1:3 (w/w wet weight) for achieving a C/N ratio of about 30. Three heaps of about 4 m3 of compost mixtures were prepared receiving a turning frequency of daily (pile A), 3-day (pile B) and weekly (pile C) turning. Different turning frequencies did not significantly affect the changes in pH and volatile solids throughout the composting period. High turning frequency caused a lower electrical conductivity and NH4-N contents as well as a shorter duration of thermophilic phase, because of a high heat loss by evaporation and volatilization of ammonia in the pile. The highest C decomposition of 4% occurred in the pile with a 3-day turning period, which coincided with the higher-nitrogen content in this treatment. All treatments with different turning frequencies reached maturation at 63 days as indicated by the soluble organic carbon, soluble NH4-N, C/N ratio and cress seed germination index. However, increasing the aeration during composting period was beneficial in accelerating the maturation process. Taking into consideration less labour and lower operation costs as compared to daily turning, it can be suggested that a 3-day turning frequency would be more appropriate for reaching acceptable quality of compost and ease in operation.

Co-composting of pig manure with leaves.

The increase in the market price of sawdust makes it a less attractive bulking agent for pig manure composting. Hence, it was the aim of this project to evaluate the feasibility of co-composting pig manure with leaves with special emphasis on its effects on compost maturity and quality. Two piles were prepared with one pile (Pile A) just constituted of pig manureand sawdust at a mixing ratio of 3:2 (w/w, fresh weight), while the other one (Pile B) with pig manure, sawdust and leaves at 3:1:1 ratio (w/w, fresh weight) to achieve a C/N ratio of 30. Each 8 m3 heap was turned and mixed every 3 days to provide sufficient aeration and the moisture content was kept at 60-70% (w/w) throughout the composting period. After 49 days of composting, dissolved organic carbon (DOC), soluble NH4-N(solid), C/N(aqueous) and C/N(aqueous) of pile A decreased to <5%, 400 mgkg(-1), 20 and 6, respectively, indicating a high degree of maturity, while pile B with leaves required only 35days. Seed germination index (GI) of pile A increased to 66.5% at day 49, while pile B to 52.4% at day 35, which was higher than the phytotoxin-free level of 50% recommended for agricultural use. This demonstrated that the addition of leaves enhanced the humification process and shortened the time required for maturation and stabilization of pig manure composting. Therefore, it is recommended to co-compost pig manure with leaves to provide a means to reutilize this waste and in the same time to reduce the dependence on sawdust as a buLking agent.

Identification of a locus for disseminated superficial actinic porokeratosis at chromosome 12q23.2-24.1.

Disseminated superficial actinic porokeratosis is an autosomal dominant cutaneous disorder characterized by many uniformly small, minimal, annular, anhidrotic, and keratotic lesions. The genetic basis for this disease is unknown. Using a genomewide search in a large Chinese family, we identified a locus at chromosome 12q23.2-24. 1 responsible for disseminated superficial actinic porokeratosis. The fine mapping study indicates that the disseminated superficial actinic porokeratosis gene is located within a 9.6 cM region between markers D12S1727 and D12S1605, with a maximum two-point LOD score of 20.53 (theta = 0.00) at D12S78. This is the first locus identified for a genetic disease where the major phenotype is porokeratosis. The study provides a map location for isolation of a gene causing disseminated superficial actinic porokeratosis.

[Molecular cloning of one splicing form of human M6b cDNA].

X-linked, early onset Pelizaeus-Merzbacher disease (PMD) and part of X-linked spastic paraplegia are caused by mutation of proteolipid protein. M6b (U45955) partially cloned by Olinsky was considered as a member of PLP gene family. One novel fragment about 300 bp partially overlapped but differed in 5'part with U45955 was obtained by nested PCR. Assembly of the novel sequence with U45955 make a 1.642kb cDNA sequence with an open reading frame encoding 265 amino acids, which was verified by sequence of PCR products from brain cDNA library. The cDNA (termed M6ba) and its deduced peptide sequence showed significant similarity to murine M6b gene and protein (91.2% and 93.4% respectively). Northern blot, PCR amplification in cDNA library and EST analysis indicated that human M6b gene has at least three splicing forms. M6ba also showed significant similarity to PLP gene, they encode strongly hydrophobic protein and all their hydrophobic region are highly conserved. Gene structure analysis showed that the coding region of M6ba was composed of seven exons.

Mutations in the gene encoding gap junction protein beta-3 associated with autosomal dominant hearing impairment.

Hearing impairment is the most commonly occurring condition that affects the ability of humans to communicate. More than 50% of the cases of profound early-onset deafness are caused by genetic factors. Over 40 loci for non-syndromic deafness have been genetically mapped, and mutations in several genes have been shown to cause hearing loss. Mutations in the gene encoding connexin 26 (GJB2) cause both autosomal recessive and dominant forms of hearing impairment. To study the possible involvement of other members of the connexin family in hereditary hearing impairment, we cloned the gene (GJB3) encoding human gap junction protein beta-3 using homologous EST searching and nested PCR. GJB3 was mapped to human chromosome 1p33-p35. Mutation analysis revealed that a missense mutation and a nonsense mutation of GJB3 were associated with high-frequency hearing loss in two families. Moreover, expression of Gjb3 was identified in rat inner ear tissue by RT-PCR. These findings suggest that mutations in GJB3 may be responsible for bilateral high-frequency hearing impairment.

[Identification of the origin of 7q+ marker chromosome in a mental retard patient].

The present chromosome-specific and chromosome-band-specific probe pools constructed by the technique of human chromosome microdissection and PCR were taken as painting probes. Using the forward chromosome painting and chromosome screening method, we had identified a chromosome additional fragment of a 7 q+ marker chromosome in a patient originated from 3 q 26-->3 qter, and ascertained the patient's karyotype was 46, XX, -7, + der (7) t (7;3) (7 pter-->7 q 32::3 q 26-->3 qter). Applying this strategy, we can identify the origin of marker chromosomes fastly and effectively.