Potential role of N-carbamoyl glutamate in biosynthesis of arginine and its significance in production of ruminant animals

Arginine （ARG） exerts many beneficial effects on animal body and enhanced angiogenesis, lactogenesis, which finally leads to the improvement in nitrogen （N） metabolism, reproduction, lactation, immunity and growth. Unfortunately, unprotected ARG will be degraded in the rumen and its price is high, thus feeding rumen-protected ARG seems to be uneconomical. Alternatively, N-carbamoyl glutamate （NCG） is structural analogue of N-acetyl glutamate, cofactor of cabamoyl phosphate synthetasel, is lower in rumen degradation compared to ARG. Additionally, rumen epithelial and duodenal cells have potentially utilized the NCG for ureagenesis. Supplementation of NCG to high yielding dairy cows increased plasma concentration of ARG and nitric oxide, decreased the plasma ammonia N and improved lactation performance and N utilization. Supplementation of NCG enhanced pregnancy rates in rats, improved litter size and fetal survival rate, thereby improved the reproductive performance of sows. Oral NCG supplementation increases plasma ARG and somatotropin levels, and increased growth rate and muscle protein synthesis in nursing piglets. The NCG is potential a relatively cheaper source of feed additive to offer vital compensation over oral administration of ARG, resulting in improved ruminant animal health and production. In this article, we reviewed the mechanism of AfiG biosynthesis by NCG and their significance in growth, reproduction, milk production and N utilization in ruminant animals.     

Deletions in the pyruvate pathway of Salmonella Typhimurium alter SPIl-mediated gene expression and infectivity

Background： Salmonella enter/ca serovar Typhimurium is a major foodborne pathogen worldwide. S. Typhimurium encodes type III secretion systems via Salmonella pathogenicity islands （SPI）, producing the major effector proteins of virulence. Previously, we identified two genes of Salmonella pyruvate metabolism that were up-regulated during chicken cell infection： pyruvate formate lyase I （pf/B） and b/functional acetaldehyde-CoA/alcohol dehydrogenase （adhE）. We were therefore interested in examining the role these genes may play in the transmission of Salmonella to humans. Methods： Mutant strains of Salmonella with single gene deletions for pflB and adhE were created. Invasion and growth in human HCT-8 intestinal epithelial cells and THP-1 macrophages was examined. Quantitative PCR was performed on 19 SPI-1 genes. Results： In HCT-8 cells, both mutant strains had significantly higher intracellular counts than the wild-type from 4 to 48 h post-infection. Various SPI-1 genes in the mutants were up-regulated over the wild-type as early as 1 h and lasting until 24 h post-infection. In THP-1 cells, no significant difference in internal Salmonella counts was observed; however, SPI-1 genes were largely down-regulated in the mutants during the time-course of infection. We also found five SPI-1 genes - hilA, hiIC hill）, sicP and rtsA - which were up-regulated in at least one of the mutant strains in log-phase broth cultures alone. We have therefore identified a set of SPI-1 virulence genes whose regulation is effected by the central metabolism of Salmonella.     

Changes in feed intake,nutrient digestion,plasma metabolites,and oxidative stress parameters in dairy cows with subacute ruminal acidosis and its regulation with pelleted beet pulp

The objectives of this study were to 1) determine the variation of nutrient digestion, plasma metabolites and oxidative stress parameters triggered by induced subacute ruminal acidosis(SARA); and 2) evaluate the ability of pelleted beet pulp(BP) as a replacement for ground corn to alleviate SARA. Eight Holstein-Friesian cows were fed four diets during four successive17-day periods: 1) total mixed ration(TMR) containing 0% finely ground wheat(FGW)(W0); 2) TMR containing 10% FGW(W10); 3) TMR containing 20% FGW(W20); and 4) TMR containing 10% BP as a replacement for 10% ground corn(BP10). The SARA induction protocol reduced the mean ruminal pH from6.37 to 5.94, and the minimum ruminal pH decreased from 5.99 to 5.41 from baseline to challenge period. Mean ruminal pH increased from 5.94 to 6.05, and minimum daily ruminal pH increased from 5.41 to 5.63, when BP was substituted for corn. The apparent digestibility of nutrients was not affected by the dietary treatments, except that the digestibility of neutral detergent fibre(NDF) and acid detergent fibre(ADF) was reduced in cows fed the W20diet compared with cows fed the W0 and W10 diets, and cows fed the BP10 diet had higher NDF and ADF digestibility than the cows fed the W20 diet. Cows fed the W20 diet had a lower plasma concentration ofβ-hydroxybutyrate(BHBA), non-esterified fatty acids(NEFA), cholesterol, triglyceride, and total antioxidative capacity(TAC), and a higher plasma concentration of glucose, insulin, malonaldehyde(MDA), super oxygen dehydrogenises(SOD), and glutathione peroxidase(GSH-Px) than cows fed the W0 diet. Substitution of BP for corn increased concentrations of plasma BHBA and TAC, but decreased concentrations of plasma MDA. Our results indicate that reduction of fibre digestion; the concomitant increase of plasma glucose and insulin; the decrease of plasma BHBA, NEFA, cholesterol, and triglyceride; and changes of plasma oxidative stress parameters are highly related to SARA induced by W20 diets. These variables may be alternative candidates for SARA diagnosis. We also suggest that the substitution of BP for corn could reduce the risk of SARA, increase fibre digestion, and improve the antioxidant status in dairy cows.     

The effects of dietary fiber level on nutrient digestibility in growing pigs

The objective of this study was to investigate the effects of total dietary fiber level on nutrient digestibility and the relationship between apparent total tract digestibility of total dietary fiber, and soluble dietary fiber, insoluble dietary fiber and available energy. Sugar beet pulp was as the only fiber source. The experiment was designed as a 6 x 6 Latin square with an adaptation period of 7 d followed by a 5-d total collection of feces and urine. Feed intake tended to decrease （P =0.] O） as total dietary fiber level increased. The apparent total tract digestibility of dry matter, crude protein and gross energy decreased （P 〈0.0]） when total dietary fiber increased but the digestibility of soluble dietary fiber and insoluble dietary fiber increased （P 〈0.01）. The digestible energy and metabolizable energy content of diets decreased （P 〈0.01） as the total dietary fiber increased.     

Porcine leptin alters isolated adipocyte glucose and fatty acid metabolism

This study examined if leptin can acutely affect glucose or fatty acid metabolism in pig adipocytes and whether leptin's actions on lipogenesis are manifested through interaction with insulin or growth hormone. Subcutaneous adipose tissue was obtained from approximately 55 kg crossbred barrows at the USDA abattoir. Isolated adipocytes were prepared using a collagenase procedure. Experiments assessed U-14C-glucose or 1-14C-palmitate metabolism in isolated adipocytes exposed to: basal medium (control), 100 nM insulin, 100 ng/ml porcine growth hormone, 100 ng/ml recombinant porcine leptin, and combinations of these hormones. Treatments were performed in triplicate and the experiment was repeated with adipocytes isolated from five different animals. Cell aliquots (250 microl) were added to 1 ml of incubation medium, then incubated for 2h at 37 degrees C for measurement of glucose and palmitate oxidation or incorporation into lipid. Incubation of isolated adipocytes with insulin increased glucose oxidation rate by 18% (P<0.05), while neither growth hormone nor leptin affected glucose oxidation (P>0.5). Total lipid synthesis from glucose was increased by approximately 25% by 100 nM insulin or insulin+growth hormone (P<0.05). Insulin+leptin reduced the insulin response by 37% (P<0.05). The combination of all three hormones increased total lipid synthesis by 35%, relative to controls (P<0.05), a rate similar to insulin alone. Fatty acid synthesis was elevated by insulin (32%, P<0.05) or growth hormone (13%, P<0.05). Leptin had no effect on fatty acid synthesis (P>0.05). Leptin reduced the esterification rate by 10% (P<0.05). Growth hormone and insulin could overcome leptin's inhibition of palmitate esterification (P>0.05).     

Restricted nutrient intake does not alter serum-mediated measures of implant response in cell culture

Background: During nutritional stress, reduced intake may reduce the efficacy of anabolic implants. This study was conducted to evaluate basic cellular responses to a growth promotant implant at two intake levels.Methods: Sixteen crossbred steers(293 ± 19.3 kg) were used to evaluate the impact of anabolic implants in either an adequate or a restricted nutritional state. Steers were trained to individual Calan gates, and then randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement. Treatments consisted of: presence or absence of an anabolic growth implant(Revalor-XS, 200 mg TBA and 40 mg estradiol; IMPLANT or CONTROL) and a moderate energy, pelleted, starting cattle diet fed at either 2.0 × or 1.0 × maintenance energy(NEM) requirements(HIGH or LOW). Serum(d 0, 14, and 28) was used for application to bovine muscle satellite cells. After treatment with the serum(20% of total media) from the trial cattle, the satellite cells were incubated for 72 h. Protein abundance of myosin heavy chain(MHC), phosphorylated extracellular signal-related kinase(phospho-ERK), and phosphorylated mammalian target of rapamycin(phospho-mTOR) were analyzed to determine the effects of implant, intake, and their interaction(applied via the serum).Results: Intake had no effect on MHC(P = 0.85) but IMPLANT increased(P 0.01) MHC abundance vs. CONTROL.Implant status, intake status, and the interaction had no effect on the abundance of phospho-ERK(P ≥ 0.23).Implanting increased phospho-mTOR(P 0.01) but there was no effect(P ≥ 0.51) of intake or intake × implant.Conclusions: The nearly complete lack of interaction between implant and nutritional status indicates that the signaling molecules measured herein respond to implants and nutritional status independently. Furthermore, results suggest that the muscle hypertrophic effects of anabolic implants may not be mediated by circulating IGF-1.     

Effects of Rumen-protected Methionine on Rumen Fermentation,lactation Performance and Plasma Characteristics in Dairy Cows

The objective was to evaluate effects of rumen-protected methionine （RP-Met） supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty-four multiparous （2.2 - 0.40 parity） Holstein dairy cows, averaged 620 ± 12.3 kg of BW, 68 ± 2.5 day in milk and daily milk production averaged 26.0 ±0.3 kg/cow were used in a replicated 4 × 4 Latin square experiment. The treatments were： control （without RP-Met）, LRP-Met, MRP-Met and HRP-Met with 20, 40 and 60 g RP-Met per cow per day, respectively. RP-Met was hand-mixed into the top one-third of the daily ration. Experimental periods were 30 days with 15 d of adaptation and 15 d of sampling. Dry matter （DM） intake and milk yields were not affected （P 〉 0.05） with increasing RP-Met supplementation. Yields of 4%FCM, ECM, milk fat and milk protein were higher （P 〈 0.03） for RP-Met supplementation than control and were quadratically （P 〈 0.05） changed due to the higher percentage of milk fat and protein for RP-Met supplementation than control （P 〈 0.03）. Ruminal pH tended to be lower （P = 0.071） for RP-Met supplementation than control, whereas total VFA concentration tended to be higher （P = 0.086） for RP-Met supplementation than control. Ratio of acetate to propionate decreased linearly （P = 0.001） from 4.01 to 3.57 as RP-Met supplementation increased due to the increase in propionate production. Digestibilities of DM, OM, CP, NDF and ADF in the total tract were higher （P 〈 0.05） for RP-Met supplementation than control and were quadratically （P 〈 0.05） increased with increasing RP-Met supplementation. Plasma concentrations of glucose not affected （P 〉 0.05） with RP-Met supplementation, Plasma concentrations of non-esterified fatty acids （NEFA） were significantly lower （P = 0.017） for RP-Met supplementation than control and were linearly （P = 0.011） changed. Plasma concentrations of beta-hydroxybutyrate tended to be lower （P = 0.068） for RP-Met supplementation than control and were linearly （P = 0.001） changed. The present results indicate that supplementation of diet with RP-Met improved the content of milk fat and protein, rumen fermentation and feed digestion, decreased plasma concentrations of NEFA. It was suggested that the RP-Met stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum RP-Met dose was about 25 g RP-Met per cow per day.     

Effects of Estradioi and Progesterone on the Numbers and Distribution of Mastocytes in the Uterus of Ovariectomized Rats

The purpose of this study was to investigate the effects of estradiol （E） and progesterone （P） on mastocyte distribution in the uterus of ovari- ectomized rats. Thirty-five adult female rats were divided randomly into seven groups：one sham operated control group （ SHAM ） ; one ovariectomized group （OVX） ;three ovariectomized plus E treatment grouPs （OVX ＋E 20,100,or 500 μg/kg body weight · d） ; and two ovariectomized plus P groups （ OVX ＋ P 2 or 10 mg/kg body weight · d）. Seven days after treatment, the contents of estradiol and progesterone in serum were detected by radioimmunoassay, and mastocytes in the uterus were stained by toluidine blue staining. Results were as following： （1） Compared to ovariectomized rat, the concent ration of estradiol in serum increased by 97. 13 % in OVX ＋ E 20 （P 〈 0.05）,204. 84 % in OVX＋E 100 （P〈0.05）,and 936.45 % in OVX ＋ E500 group （P〈0.05）;the progesterone concent ration increased by 77.25 % in OVX ＋P 2 （P 〈0.05） and 235.25 %in OVX ＋P 10 group （ P 〈 0.05 ）. （2） Compared to ovariectomized rat, the number of mast cells in uteri decreased by 32.65% in OVX ＋E 20,64.50 % in OVX ＋E 100 （P〈0.05）,74.49 % in OVX＋E500 （P〈0.05） and 70.67 % in OVX ＋P 10 groups （P〈0.05）. However, the number of mast cells increased by 66.73% in OVX ＋ P 2 group （ P 〈 0.05 ） compared with OVX. The trend of mast cells number in the rat uterus was decreased gradually with the increase of estrogen or progesterone concent ration. The number of mast cells in ovariectomized rat uterus was affected by estrogen or progesterone. These results demonstrated that estrogen or progesterone directly affected the number of mast cells in the uterus of rat.     

Predicting corn digestible and metabolizable energy content from its chemical composition in growing pigs

Background： The nutrient composition of corn is variable. To prevent unforeseen reductions in growth performance, grading and analytical methods are used to minimize nutrient variability between calculated and analyzed values. This experiment was carried out to define the sources of variation in the energy content of corn and to develop a practical method to accurately estimate the digestible energy （DE） and metabolisable energy （ME） content of individual corn samples for growing pigs. Twenty samples were taken from each of five provinces in China （Jilin, Hebei, Shandong, Liaoning, and Henan） to obtain a range of quality. Results： The DE and ME contents of the 100 corn samples were measured in 3.5.3 ±1.92 kg growing pigs （six pigs per corn sample）. Sixty corn samples were used to build the prediction model; the remaining forty samples were used to test the suitability of these models. The chemical composition of each corn sample was determined, and the results were used to establish prediction equations for DE or ME content from chemical characteristics. The mean DE and ME content of the 100 samples were 4,053 and 3,923 kcal/kg （dry matter basis）, respectively. The physical characteristics were determined, as well, and the results indicated that the bulk weight and 1,000-kernel weight were not associated with energy content. The DE and ME values could be accurately predicted from chemical characteristics. The best fit equations were as follows： DE, kcal/kg of DM = 1062.68 ＋ （49.72 ×EE） ＋ （0.54 × GE） ＋ （9.1 ] x starch）, with R^2 = 0.62, residual standard deviation （RSD） = 48 kcal/kg, and P 〈 0.01; ME, kcal/kg of dry matter basis （DM） = 671.54 ＋ （0.89 ×DE） - （5.57 × NDF） - （191.39 ×ash）, with R^2 = 0.87, RSD = 18 kcal/kg, and P〈 0.01. Conclusion： This experiment confirms the large variation in the energy content of corn, describes the factors that influence this variation, and presents equations based on chemical measurements that may be     

Mammary gland growth and vascularity at parturition and during lactation in primiparous ewes fed differing levels of selenium and nutritional plane during gestation

Background： Objectives were to examine the effects of selenium （Se） supply and maternal nutritional plane during gestation on mammary gland growth, cellular proliferation, and vascularity at parturition and d 20 of lactation. Rambouillet primiparous ewes （n = 84） were allocated to treatments in a 2 x 3 factorial. Factors were dietary Se （adequate Se [ASe, 11.5 μg/kg BW] or high Se [HSe, 77.0 μg/kg BVV]） and nutritional plane （60% IRES], 100% [CON], or 140% [EXC]）. At parturition, lambs were removed and 42 ewes （7/treatment） were necropsied. Remaining ewes were fed a common diet meeting requirements for lactation and mechanically milked twice daily until necropsy on d 20. At both necropsy periods, mammary glands were dissected and tissues harvested. Samples were analyzed for RNA, DNA, and protein content, cell proliferation, and vascularity. Where interactions were present （P 〈 0.05）, least squares means from the highest-order interaction are presented. Results： Final body weight of ewes was least （P 〈 0.002） in RES, intermediate for CON, and greatest for EXC, regardless of stage of the ewe at necropsy （parturition or d 20 of lactation）. In ewes necropsied at parturition, mammary glands were heavier （P = 0.02） in EXC compared to RES, with CON intermediate. Concentration of RNA （rag/g） was decreased （P= 0.01） in EXC compared to CON at parturition. There was a tendency （P= 0.07） for a Se by nutrition interaction in percentage of cells proliferating where ASe-EXC ewes had greater （P_〈 0.02） number of proliferating cells then all other treatments. Mammary vascular area tended （P = 0.08） to be affected by a Se by nutrition interaction where ASe-CON had less （P= 0.007） vascular area than HSe-CON ewes. In ewes necropsied at d 20 of lactation, the number of alveoli per area was decreased （P 〈- 0.05） in RES compared to CON and EXC-fed ewes. Conclusions： Results of this study indicate that proper maternal nutritional plane during gestation is important for mammary gland development, even out to d 20 of lactation.     

Changes of hepatic biochemical parameters and proteomics in broilers with cold-induced ascites

Ascites syndrome is still a problem for chicken industry in various parts of the world. Despite the intensive investigations of this syndrome for many years, its pathogenesis remains unclear. The objective of this study was to analyze the difference in hepatic proteomics between ascites and healthy broilers by two-dimensional electrophoresis （2-DE） and matrix-assisted laser desorption/ionization-time of flight mass spectrometry （MALDI-TOF-MS）. Changes of biochemical parameters of liver and blood were also determined. The results indicated that red blood cell counts （RBC）, hematocrit （HCT） and haemoglobin （HGB） of ascites broilers were significantly greater than healthy broilers. Hepatic malondialdehyde （MDA） level of ascites broilers was significantly increased, and the activity of total superoxide dismutase （T-SOD） was significantly decreased. Hepatic lactic acid （LD） level of ascitic broilers were significantly lower than healthy ones, Serum glucose and cholesterol level of ascites broilers were significantly increased, and serum globulin level was significantly decreased in ascites broilers. There was no significant difference in triglyceride （TG） and blood urea nitrogen （BUN） level. The activity of liver hexokinase （HK） and succinodehydrogenase （SDH） in ascites broilers was significantly decreased, and there was no significant difference in the activity of liver pyruvate kinase （PK） and Na＋-K＋-ATPase. The hepatic proteomics analysis showed that 18 proteins expression difference were identified between ascites and healthy broilers. These proteins were mainly involved in： 1） cytoskeleton; 2） glucose, lipids and amino acid metabolism; 3） cell secretion; 4） cell apoptosis; 5） signal transduction; 6） immune and inflammatory response; and 7） cellular redox homeostasis. Mitochondrial isoform phosphoenolpyruvate carboxykinase （M-PEPCK） mainly participates in gluconeogenesis of chicken liver. In conclusion, liver oxidative damage was significantly aggravated, but antioxidant capacity was decreased in cold-induced ascites broilers. Serum glucose level was significantly increased, with liver M-PEPCK expression higher in ascites broilers, which implied that some potential regulatory reagents may reduce ascites susceptibility and mortality under cold temperature by increasing liver gluconeogenesis level.     

In vitro Evaluation of Feed Aspergillus sulphureus Enzyme Compound Produced by in Solid-state Fermentation

ABSTRACT： Three trials were conducted to analyze a multi-enzyme compound produced by Aspergillus sulphureus in solid-state fermentation （SSF） as a po- tential feed additive. The results of the first trial showed that there were at least 5 non-starch polysac- charide enzymes： xylanase, 13-ghicanase, pectinase, mannase and carboxy methyl cellulase （CMCase） contained in the compound. Xylanase and fl-glucanase showed good activities at pH 2.5-7.0, which were in the range of 649-1046 U/g and 444-648 U/g, respec- tively. Pectinase showed good activity in acidic solu- tion （pH 2.5-3.0）,which ranged from 195 to 917 U/g. Mannase showed high activity of 235-298 U/g at pH 3.5-4.5 and the activity of CMCase was relatively constant at pH 2.5-7.0, which was in the range of 38.2-78.6 U/g. The second trial was aimed to test the stability of the enzymes in gastric liquor （pH 2.6） of finishing pigs and Na2 HPO4-gastric liquor （ pH 5.5 ）.After 6 h incubation at 40℃ in gastric liquor,the re- tained activity of xylanase, 13-glucanase, pectinase, mannase and CMCase was 26.3% ,65.0% ,71.0%, 74.8% and 85.6%, respectively. While after 6 h in- cubation at 40℃ in Na2I-IPO4-gastric liquor, the re- tained activity of xylanase, [3-glucanase, pectinase, mannase and CMCase was 87.9% ,91.1% ,92.3%, 95.0%, and 97.5%, respectively. The third trial was carried out in a jejunum liquor （ pH 5.8,200 mL）, which contained 0.2 g of the multi-enzyme compound and 10 g of soybean hull or wheat bran, respectively. After 8 h incubation at 40℃, 18.7% of soybean hull and 20.1% of wheat bran could be degraded to solu- ble saccharide, respectively. Compared with the tradi- tional methods for feed enzyme testing which involve feeding animals for 1-3 months, enzyme assay in this way was relatively convenient.     

The Effect of Dietary Sulphate Copper Supplementation on Growth Performance,Intestinal Digestive Enzymes and Absorptive Transporters in Weanling Pigs1

The experiment was conducted to as- sess the effects of dietary supplementation of Cu on the growth performance, digestive enzymes, tissue minerals and absorptive transporters in small intestinal mucosa of weanling pigs. One hundred crossbred pigs weaned at 28 ＋ 2 d of age were assigned randomly to one of the following diets with 5 replicates：corn-soy- bean basal diet with 10,100,175,250 mg/kg of Cu as CuSO4·5H20. The results showed that 250 mg/kg Cu had a positive effect （ P 〈 0.05） on average daily gain, daily feed intake and ratio of gain/feed. Com- pared to 10 mg/kg Cu, higher Cu had significant effect on the apparent digestibility of protein and fat （P 〈 0.05 ）. The supplementing of Cu improved am- ylase and lipase activity in jejunum content and lipase in pancreas （ P 〈 0.05） and had no effect on intestinalmorphology. The liver Cu elevated approximately 4- fold in pigs fed diet with 250 mg/kg Cu compared with pigs fed diet with 10 mg/kg Cu, no increases were observed in pigs receiving the lower level of Cu （100 and 175 mg/kg）. Both Fe and Zn contents in kidney and liver were not affected by Cu supplemen- tation. There was no positive effect （ P 〉0.05） of Cu supplementation on PepT1 （peptide transporter 1 ） and SGLT1 （sodium/glucose cotransporter） mRNA abundance in intestinal mucosa. However, higher sup- plementing level （250 mg/kg） significantly elevated the DMT1 （divalent metal transporter） mRNA abun- dance in duodenum mucosa. These results suggested that dietary supplementation with 250 mg/kg Cu could improve growth performance, nutrient digestibil- ity and intestinal enzyme activities of weanling pigs.     

Conjugated Linoleic Acid and Dietary Fats Differentially Affect Hepatic ACAT Activity and LDL-Cholesterol in Postweanling Pigs Fed Low-Fat Diets1

ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.     

Correlation analysis of the total IgY level in hen serum,egg yolk and offspring serum

The correlation between IgY levels of the serum and the yolk has been well documented in wild and domestic birds. The levels of total yolk IgY can be an index of the general health status of birds and may contribute to breeding programs when fitness of the offspring is a concern. We measured the levels of total serum IgY and yolk IgY in three different breeds （White Leghorn, Silkie and Dongxiang blue-shell） using indirect ELISA, and found that there was a significantly positive correlation between the levels of total serum IgY and total yolk IgY in all three breeds （White Leghorn： r = 0.404, P 〈 0.001, n = 100; Silkie： r = 0.561, P 〈 0.001, n = 70; Dongxiang blue-shell： r = 0.619, P 〈 0.001, n = 30）. We also measured the total serum IgY levels in the 3-day-old offspring hatched from the Silkie hens and results were significantly correlated for serum IgY levels （r = 0.535, P 〈 0.001, n = 70） and the yolk IgY levels （r = 0.481, P 〈 0.001, n = 70）. The regression analysis showed simple linear regression between IgY levels in hen serum, yolk and offspring serum. Our results suggest that total IgY level could be used as an index for chicken fitness.     

Effects of dietary vitamin and fatty acid content in E on muscle vitamin E Aohan fine-wool sheep

Background： Increasing the polyunsaturated fatty acid （PUFA） content and decreasing the saturated fatty acid （SFA） content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid （FA） composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep. Methods： Forty-two male Aohan fine-wool lambs （5 mo old） with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 （control group）, 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the Iongissimus lumborum （LL） and gluteus medius （GM） muscles. Results： Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation （P 〈 0.05）. However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA （MUFA） content in the LL and GM （P 〈 0.05）. All six doses of vitamin E significantly increased cis9 tronsl -conjugated linoleic acid （cgtl -CLA） content in the LL compared with the control group （P 〈 0.05）. Conclusions： Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c9tl 1-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E.     

Comparative Study on Nitrogen Metabolism and the Nitrogen Maintenance Requirement in Lohmann Brown Roosters and Layers1

The objective of this study was to in- vestigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohm- ann Brown adult roosters and layers. The nitrogen ma- intenance requirement （Nm ） was determined based on the nitrogen balance. Thirty Lohmann Brown adult roosters and 30 laying hens at 27 weeks of age were randomly divided into five groups of six birds per group. The birds were fed with one of five diets con- taining 10.46%, 11.77%, 13.79%, 16.77% or 18.29% of crude protein. Nitrogen intake, nitrogen retention and nitrogen retention efficiency were higher in roost- ers than in laying hens, and the average nitrogen re- tention rate for groups fed with CP level of 11.77%, 13.79%, 16.77% and 18. 29% was improved by9.14%. The nitrogen maintenance requirement for Lohmann Brown roosters and laying hens at 27 weeks of age were 0.4245 g/d and 0.5059 g/d, respective- ly, and Nm based on average body weight （BW） and metabolic body weight （ BW~Ts ） was 0.2364 g/kg BW and 0. 2739 g/kg BW~＇75 for laying hens and 0. 2754 g/kg BW and 0. 3208 g/kg BW~72 for roost- ers, respectively. The regression equations for daily N gain （NB, protein accretion） vs. daily N intake （NI ） for Lohrnann Brown layers and roosters were NB = 0.3743NI -0.1589（R2 =0.79） and NB =0.6228NI - 0.3151 （ R2 = 0.85 ）, respectively. The results of this study indicate that nitrogen intake and nitrogen reten- tion at the same dietary CP level were higher in roost- ers than in laying hens.     

Influence of Montmoriilonite Nanocomposite on Tissue Levels of Lead and Blood Biochemical Parameters in Pigs Exposed to Lead1

ABSTRACT： Eighteen （Duroc x Landrace x Yorkshire） castrated boars, 55 days of age and weig- hing approximately 19 kg, were used to investigate the effects of montmorillonite nanocomposite on tissue levels of lead as well as changes in blood biochemical parameters in pigs fed lead contaminated diets. The barrows were randomly assigned to one of three treat- ments （n = 6） including a control which were fed a basal diet based on corn and soybean meal. The re- maining two groups were fed the basal diet supple- mented with 10 mg/kg lead either with or without 0.5% montmorillonite nanocomposite for 50 days. Pigs treated with lead had significantly increased lev- els of lead in their tissues. Lead accumulated in all tis- sues of the body with the highest accumulation found in the hair. When montmorillonite nanocomposite was given along with lead, tissue concentrations of lead did not differ from the control. Fecal excretion of leadincreased significantly in lead-exposed pigs treated with montmorillonite nanocomposite. A progressive and appreciable accumulation of lead was seen in blood with a concomitant increase in zinc protopor- phyrin levels during the course of treatment. Howev- er, zinc protoporphyrin levels did not differ from the control when montmorillonite nanocomposite was ad- ministered along with lead. The activity of ~-amino le- vulinic acid dehydratase in blood was significantly in- creased in lead treated pigs compared with the con- trol. However, in pigs treated with lead and montmo- riltonite nanocomposite in combination, the activity of δ-amino levulinic acid dehydratase was similar to con- trol pigs. Our results indicate that montmorillonite nanocomposite treatment of pigs exposed to lead re- suited in reduced lead concentrations in body tissues. It appears that montmorillonite nanocomposite func- tions by increasing fecal excretion of lead.     

Astragalus polysaccharide enhances immunity and inhibits H9N2 avian influenza virus in vitro and in vivo

This study investigated the humoral immunization of Astragalus polysaccharide （APS） against HgN2 avian influenza virus （H9N2 AIV） infection in chickens. The effects of APS treatment on H9N2 infection was evaluated by an Mqq- [3（4, 5-dimethylthiazol-2-yl）-2, 3-diphenyl tetrazolium bromide] assay and analysis of MFIC and cytokine mRNA expression. The effect on lymphocyte and serum antibody titers in vivo was also investigated. IL-4, IL-6, IL-10, LITAF, IL-12 and antibody titers to H9N2 AIV wet enhanced in the first week after APS treatment. The results indicated that APS treatment reduces H9N2 AIV replication and promotes early humoral immune responses in young chickens.This study investigated the humoral immunization of Astragalus polysaccharide （APS） against HgN2 avian influenza virus （H9N2 AIV） infection in chickens. The effects of APS treatment on HgN2 infection was evaluated by an M]q- [3（4, 5-dimethylthiazol-2-yl）-2, 3-diphenyl tetrazolium bromide] assay and analysis of MHC and cytokine mRNA expression. The effect on lymphocyte and serum antibody titers in vivo was also investigated. IL-4, IL-6, IL-10, LITAF, IL-12 and antibody titers to PIgN2 AIV were enhanced in the first week after APS treatment. The results indicated that APS treatment reduces HgN2 AIV replication and promotes early humoral immune responses in young chickens.