Effect of Feeding Pellet Diets on Intake，Digestion and Metabolism of Pregnant Ewes

16 adult Small Tail Han ewes,with body weight of 53 kg,were randomly divided into 4 groups （n＝4）,the roughage-type ground diet （GD）（group 1） or pellet diet （PD）（group 2）（67% cornstalk）,and the concentrate-type GD （group 3） or PD （group 4）（50% cornstalk） were fed from the 50th day of pregnancy.Two digestion-metabolism experiments at the 60 to 76 and 120 to 136 d of pregnancy were carried to study the effect of feeding PDs on the intake,digestion and metabolism of pregnant ewes.The results showed that under the conditions of roughage-type ration （RTR） and concentrate-type ration （CTR）,the DM voluntary intake of ewes was increased by 44.8%（P＜0.01） and 46.0%（P＜0.01） at early pregnant stage （EPS）,respectively,and 58.7%（P＜0.01） and 58.5% （P＜0.01） at later pregnant stage （LPS）,respectively.The apparent digestibility of DM was decreased by 6.2%（P＞0.05） and 6.0% （P＞0.05） at EPS,respectively,and 8.0%（P＞0.05） and 1.6%（P＞0.05） at LPS,respectively. The apparent digestibility of CP was decreased by 13.9%（P>0.05） and 2.3%（P＞0.05） at EPS,respectively,and 4.8%（P＞0.05） and 3.9% （P＞0.05） at LPS,respectively. The apparent digestibility of energy was decreased by 2.9%（P＞0.05） and 5.7%（P<0.05） at EPS,respectively,and 0.5%（P＞0.05） and 8.2%（P＜0.01） at LPS,respectively.However,under the conditions of RTR and CTR,by feeding PD the digested amount of DM of ewes was increased by 19.7%（P＜^R0.05） and 37.0%（P＜0.01） at EPS,respectively,and 65.8% （P＜0.01） and 46.3%（P＜0.01） at LPS,respectively.The digested CP amount of ewes was increased by 31.2%（P＜0.01） and 30.4% （P＜0.05） at EPS,respectively,and 60.1% （P＜0.01） and 56.4% （P＜0.01） at LPS,respectively. The amount of digestible energy was increased by 54.6%（P＜0.01） and 36.8%（P＜0.01） at EPS,respectively,and 105.2%（P＜0.01） and 63.8% （P＜0.01） at LPS,respectively. Under the conditions of RTR and CTR,by feeding PD the nitrogen retention of ewes was increased by 74.5%（P＜0.01） and 44.7%（P＜0.05） at EPS,respectively,and 101.1%（P＜0.01） and 73.4%（P＜0.01） at LPS,respectively. The birth weight of lamb was increased by 26.3%（P＜0.05） and 34.8%（P＜0.01）,respectively. It was concluded that by feeding PD the voluntary intake of pregnant ewes could be increased. The digestibility of diet had the tendency to decrease,but the digested amount was increased very significantly. By feeding PD the nitrogen retention of ewes and the birth weight of lamb were increased.Therefore,feeding PD was an effective way for increasing nutrient supply to pregnant ewes.     

Truncated Expression and Activity Detection of Porcine Epidemic Diarrhea Virus S Protein，and Preparation of its Polyclonal Antibody

In order to highly express S protein of porcine epidemic diarrhea virus (PEDV) and prepare its specific polyclonal antibody,the main antigen region of S gene was amplified by PCR method,subcloned into pET30a(+) prokaryotic expression vector,transformed into BL21(DE3) expression bacteria,and induced by IPTG.The recombinant S protein was purified by affinity chromatography,its activity was detected by Western blotting,New Zealand White rabbits were immuned using the recombinant S protein to prepare polyclonal antibody,and detection of the antibody titer by indirect ELISA was conducted. After BamHⅠ/HindⅢ double enzyme digestion, we obtained pET30a-S recombinant plasmid,with induction of 1 mmol/L IPTG for 4 h,the recombinant S protein were expressed in inclusion body form,after purification and Western blotting,the protein showed good activity and specificity,antibody titer of polyclonal antibody against S protein was 1∶25600 detected by indirect ELISA. In this study PEDV S protein was successfully truncated expressed and its polyclonal antibody was also prepared,which layed a foundation for further development of rapid immunology detection kit of porcine epidemic diarrhea,and provided a condition for the study of structure and function of S protein and identification of the antigenic epitopes.     

Isolation，Identification and Antibiotics Resistance Analysis of Enterococcus from Yak

17 feces samples of yak which were collected in Hongyuan county were measured with Gram staining method and 16S rRNA molecular identification in this study.8 suspected Enterococcus were separate from feces samples by bacteria purification and PCR amplification with 1 500 bp specific band. 6Enterococcus faecalis and 2Enterococcus faecium were identified through 16S rRNA sequencing.The homology analysis of the strains revealed that the homology between Enterococcus faecalis and reference strains sequence were 99.7% to 100%,that of Enterococcus faecium and reference sequence were 98.2% to 99.2%,indicating that the yak Enterococcus was highly conserved in the process of genetic evolution.The drug sensitive test results showed that the isolated strains were highly resistance to aminoglycoside antibiotics.Enterococcus faecium 11-1-2 strain was not only 5 multi-resistant,but also showed resistence to vancomycin.Enterococcus faecalis strains was most 3 multi-resistant.The antibiotics resistance results revealed that the resistance of yak Enterococcus was serious and should be taken seriously.     

Effect of Herbal Compound Outikang on Antibody Titer of Foot and Mouth Disease Vaccine，Cytokines and Biochemical Indices in Cows

The experiment was aimed to study the effects of herbal compound Outikang on antibody titer of foot and mouth disease vaccine type O,type A and type Asia Ⅰ,serum levels of ten cytokines and biochemical indices. 200 healthy adult cows were averagely divided into drug group and blank control group. Vaccinating the cows with FMD triplex vaccine when Outikang was given to the cows of drug group for 7 d running and then got the blood of all the cows on 0, 14, 28 and 56 d, respectively. Then blood biochemical examination, vaccine effectiveness and serum levels of cytokines were performed. The results showed that there were no significant differences in antibody titer of FMDV between blank control group and drug group on 0, 28 and 56 d after vaccination (P>0.05), while on 14 d the effect of Outikang on antibody titer of FMDV reached extremely significant level (P<0.01). Compared with blank control group, the contents of T-Bil in drug group was significantly decreased on 0 and 28 d (P<0.05), while it was extremely significantly decreased on 56 d (P<0.01).Compared with blank control group, the contents of Glu had significant difference on 28 and 56 d (P<0.05).The contents of P had extremely significant difference on 0 d (P<0.01), which was within the normal range. On 14 d after vaccination, the content of CD4 significantly increased in the drug group comparing to those in blank control group (P<0.05). On 28 d after vaccination, the content of CD4, IL-2, IL-6, IL-10, IL-12, IL-18 and IFN-γ extremely significantly increased in the drug group comparing to those in blank control group (P<0.01). On 56 d after vaccination, the contents of IL-6 and IL-12 extremely significantly increased in the drug group comparing to those in blank control group (P<0.01), while the content of CD4, IL-2, IL-4 and IL-18 significantly increased (P<0.05). Therefore, Outikang could significantly rise the antibody titer of foot and mouth disease vaccine type O, type A and type Asia Ⅰ.While it had no damage to the liver and kidney functions and had cholagogue effect, and it could enhance cellular immunity and humoral immunity function obviously.     

Effect of Astragalus Polysaccharin on Growth Performance，Intestinal Microflora and Immune Function of Immunosuppression Broilers

The aim of this study was to explore the effect of different levels of Astragalus polysaccharin on growth performance,intestinal microflora and immune function of immunosuppression broilers.A total of 180 fast large yellow feather chickens with similar weight were randomly divided into 4 groups,with 3 replicates of 15 chicks in each replicate,group Ⅰ was fed with basal diet,free drinking water,groupsⅡ,Ⅲ,Ⅳ were add 200 mg/L water soluble florfenicol in the drinking water,medication for 6 days,then group Ⅱ was fed a basal diet,groups Ⅲ,Ⅳ were fed with basal diet supplemented with 500 and 1000 mg/kg Astragalus polysaccharin,respectively.The pre-trial period lasted for 7 days,and the experiment lasted for 35 days.The results showed that compared with group Ⅱ,groups Ⅲ and Ⅳ was significantly improved the growth performance of immunosuppression broilers （P＜0.05）,enhanced the number of beneficial bacteria （Lactobacillus and Bifidobacterium） in the gastrointestinal tract of immunosuppression broilers （P＜0.05）,reduced the number of harmful bacteria （Escherichia coli and Salmonella） in the gastrointestinal tract of immunosuppression broilers （P＜0.05）,improved the immune organs index and Newcastle disease antibody titer of immunosuppression broilers （P＜0.05）,decreased the serum contents of IL-10 and IFN-γ of immunosuppression broilers （P＜0.05）.In conclusion,adding 500 and 1000 mg/kg Astragalus polysaccharin in diet could eliminate immunosuppression effect of florfenicol test,improve the growth performance,adjust the intestinal micro ecological balance and ennhance the immune function of broilers.     

Time course of oxidative phosphorylation in liver mitochondria of chickens fed on high‐protein diet

1. Progressive alterations in oxidative phosphorylation of liver mitochondria were followed for 14 d in growing chickens fed on either semi‐purified low (7%) or high (61%) protein‐energy diet. Hepatic mitochondrial oxidative phosphorylation rates were assessed polarographically with pyruvate + malate as substrates.

2. The ADP:O values were reduced significantly 4 d after the feeding of a high‐protein‐energy diet, when compared with those in chickens fed on a low‐protein‐energy diet, whereas the state 3 oxidation rates in chickens fed on a high‐protein‐energy diet from day 6 to 14 were significantly lower than those in low‐protein‐fed chickens.

3. No changes in sensitivity of mitochondrial ATPase activity to oligomycin, expressed as % of total ATPase activity, were observed among chickens fed for 21 d on diets with various protein concentrations though the FoF₁‐ATPase activity, expressed per mg protein, tended to decrease in chickens fed on high‐protein‐energy diet.

4. These results suggest that the reduced ADP:O values for liver mitochondria in the high‐protein‐fed chickens may not be involved in the degrees of integrity of the FoF₁‐ATPase.     

Identification，Virulence and Drug Resistance Analysis of Escherichia coli from Diarrhea Piglets

In order to clarify the pathogenic characteristics and drug-resistant spectrum of a newborn piglet diarrhea outbroke recently in a large-scale pig farm of Henan province, the study was carried out by the isolation of intestinal pathogenic Escherichia coli and system identification. Escherichia coli strains were isolated from the faeces of diarrhea piglets. 13 virulent genes were tested by PCR. The antibiotic susceptibility of the strains was determined. The results showed that the positive rate came up with 34.8% for EAST1 gene. All of the strains were multiple-drug resistance and resistant to at least 5 types of antibiotics. 75.3% strains were resistant to more than 9 types of antibiotics. All of the strains were resistant to ampicillin, piperacillin, ciprofloxacin, levofloxacin and moxifloxacin. The result of the phylogenetic background showed that 21.7% E.coli isolates belonged to group B2 and D which were pathogenic. According to the synthesis analysis of virulence factors, resistance and phylogenetic background of the strains isolated from the diarrhea piglets, proper clinical treatment and prevention and control measure could be provided.     

Study on the Isolation，Identification and Probiotic Characteristics of a Bacillus coagulans

This experiment was conducted to isolate and identify a strain of Bacillus coagulans from the soil at the bottom of the pond, and study its probiotic properties. A strong acid producing bacillus was isolated from the soil at the bottom of the pond and identified as Bacillus coagulans through the physiological and biochemical characteristics and 16S rDNA sequence analysis. The strain had high tolerance to the simulated gastric juice (pH 2.5, 12 h of incubation, survival rate was 71.9%) and simulated intestinal fluid (bile salt concentration 0.3%, 12 h of incubation, survival rate was 84.4%) and had high antibacterial activity to E.coliK88, E.coliK99, S.agalactiaeand A. hydrophila. It could degrade nitrite effectively and the degradation rate was 96.80% in 48 h. Two hundred and seventy AA broilers aged 1 day were randomly allocated into 3 groups. Diets were added 0 (group Ⅰ), 1.0×10⁶ (group Ⅱ) and 1.0×10⁷ CFU/g (group Ⅲ) Bacillus coagulans NJ102, respectively. The experiment lasted for 42 d. The average daily gain and final body weight of group Ⅱ and Ⅲ were significantly higher than that of group Ⅰ(P<0.05), and the feed weight ratio of the two groups were significantly lower than that of groupⅠ(P<0.05). There was no significant difference in average feed intake among three groups (P>0.05). It was found that the soil-derived Bacillus coagulans NJ102 from the bottom of the pond had a certain degree of resistance and potential probiotic ability, which could improve the growth performance of broilers and had the potential to be a microbial feed additive.     

Effects of Antibacterial Peptide Cecropin on Prouduction Performance，Immune Function and Serum Biological Parameters of Weaner Piglets

This experiment was conducted to study the effects of antimicrobial peptide cecropin on production performance,immune function and serum biological parameters of weaner piglets.A total of 240 weaner hybrid piglets （Landrace×Large White×Duroc） with average body weight （8.35±0.12）kg were randomly divided into 4 treatments with 6 replicates of 10 each.The four treatments were control group （fed a basal diet）,antibiotics group （fed basal diet＋140 mg/kg 50% kitasamycin＋100 mg/kg olaquindox ＋600 mg/kg 10% colistin sulfate）,antimicrobial peptide group （fed basal diet＋350 mg/kg antimicrobial peptide cecropin）,compatibility group （antibiotics + antibacterial peptide group）（fed basal diet＋250 mg/kg antimicrobial peptide cecropin＋50 mg/kg olaquindox ＋200 mg/kg 10% colistin sulfate）,each group was half male and half female.The pre-test period lasted for 7 days,the trial period lasted for 34 days.The results showed that compared with control group,the average daily gain in compatibility group was significantly increased （P＜0.05）,the average daily feed intake in antibiotic group and antimicrobial peptide group was significantly decreased （P＜0.05）,the feed conversion ratio and diarrhea rate in all three experimental groups were significantly decreased （P＜0.05）.The antibody blocking rate and serum IgG,IgA contents in antimicrobial peptide group and compatibility group were significantly increased （P＜0.05）,the serum urea nitrogen and blood sugar contents in antimicrobial peptide group and compatibility group were significantly decreased （P＜0.05）,but the serum total protein and albumin contents were significantly increased （P＜0.05）.In conclusion,dietary supplementation appropriate level of antimicrobial peptide cecropin could replace part of the antibiotics,and adding high dose of antimicrobial peptide cecropin could replace antibiotics used in feed completely.     

Effects of Wheat and Fermented Sesame Meal on Growth Performance，Meat Quality and Serum Biochemical Indexes in Broilers

This study was to investigate the effects of different proportions of wheat and fermented sesame meal on growth performance,meat quality and serum biochemical indexes in broilers under the condition of adding exogenous enzymes in the diet.A total of 520 21-day-old broilers （fast）with an average body weight of （330±10）g were randomly assigned to 5 groups with 4 replicates in each group and each replicate contained 26 broilers. Broilers in the 5 groups were fed experimental diets containing 0 (control group),20% wheat +5% fermented sesame meal （group Ⅰ）,40% wheat +10% fermented sesame meal （group Ⅱ）,20% wheat + soybean meal （group Ⅲ） and 40% wheat + soybean meal （group Ⅳ）,respectively.The pre-test period lasted for 3 days and the trial period lasted for 34 days.The results showed that compared with the control group,the ADG in groups Ⅰ,Ⅱ,Ⅲ and Ⅳ was significantly decreased by 9.40%,7.15%,8.87%,5.46% （P＜0.05）,respectively,while the ADFI and F/G showed no significant differences （P＞0.05）.There were no significant differences on meat quality among all experimental groups（P＞0.05）, respectively, but group Ⅱ had better meat quality than others.Compared with the control group,the content of alanine aminotransferase in serum in groups Ⅲ, Ⅳ was significantly decreased by 30.10%,25.36% （P＜0.05）,but there were no significant differences in the contents of total protein,urea nitrogen and aspartate aminotransferase in serum in all experimental groups（P＞0.05）.In conclusion,under the experimental conditions,adding appropriate proportions of wheat and sesame meal could replace part of the corn and soybean meal in the diet,and the better supplementation level of wheat and fermented sesame meal was 40% and 10%,respectively.     

Effects of Oral Echinacea purpurea on Heart Rate，ECG,Blood Pressure and Respiration of Awake Beagle Dogs

The experiment studied the effects of oral Echinacea purpurea on heart rate, ECG, blood pressure and respiration of awake Beagle dogs. Experimental results showed that oral Echinacea purpurea 0.125 to 1.25 g/kg could apparently reduced the heart rate of awake Beagle dogs, and had no significant effects on blood pressure, respiration and ECG between P wave, T wave, R wave, QT interval, PR interval as well as QRS duration （P>0.05）. It showed that Echinacea purpurea had no apparent effects on the dog’s respiratory system and cardiovascular system, which was safe and reliable in application doses.     

Effect of Different Ratios of Food to Water of Dry Powder Feed on Growth Performance，Nutrient Digestibility and Nitrogen Metabolism of Growing Wusuli Raccoon Dogs

This experiment was aimed to explore the effect of different ratios of food to water of dry powder feed on growth performance,nutrient digestibility and nitrogen metabolism of growing Wusuli raccoon dogs.Thirty 11-week-old healthy Wusuli raccoon dogs with average body weight of （3.47±0.20） kg were randomly assigned into 3 groups.The Wusuli raccoon dogs were fed experimental diets with dry powder feed of ratio of food to water of 1∶2.5 （group Ⅰ）,1∶3.5（group Ⅱ）,1∶4.5 （group Ⅲ）,respectively.The pre-test period lasted for 7 days and the trial period lasted for 67 days.The results showed that the average daily feed intake of each week from 11,12 to 13 weeks in groupⅠ was significantly less than that in groups Ⅱ and Ⅲ （P＜0.05）,the average daily feed intake of each week from 14,15 to 20 weeks was no significant difference among all groups （P＞0.05）.The total intake in group Ⅰ was significantly less than that in group Ⅱ （P＜0.05）.The average daily gain of each week from 15 to 17 weeks in group Ⅲ was significantly higher than that in group Ⅰ （P＜0.05）,while the average daily gain,total weight and the rate of feed intake to body gain in other week-old were no significant differences among all groups （P＞0.05）.The protein digestibility,fat digestibility and dry matter digestibility were no significant differences among all groups （P＞0.05）.The amount of urine in group Ⅲ was extremely significantly higher than that in groups Ⅰ and Ⅱ （P＜0.01）.The nitrogen intake,fecal nitrogen,urine nitrogen,nitrogen deposition,net protein utilization and biological value of protein were no significant differences among all groups （P＞0.05）.In conclusion,the appropriate ratios of food to water of dry powder feed of growing Wusuli raccoon dogs was 1∶3.5 to 1∶4.5.     

Dose dependent disposition of sulphadimidine and of its N4‐acetyl and hydroxy metabolites in plasma and milk of dairy cows

Summary

The disposition of sulphadimidine (SDM) and of its N₄‐acetyl (N₄‐SDM) and two hydroxyl metabolites, 6‐hydroxymethyl‐ (SCH₂OH) and 5‐hydroxyasulphadimidine (SOH), was studied in plasma and milk of dairy cows following intramuscular or intravenous administration of sulphadimididine‐33.3% at doses of 10, 45, 50, and 100 mg/kg. The main metabolite in plasma as well as in milk was SCH₂OH. The metabolite percentages, the final plasma elimination half‐lives, and the time of peak SDM concentrations in milk are presented for different dosages. The concentrations of SDM and its metabolites in milk ran parallel to those in plasma beyond4 hours p.i. The metabolite concentrations in plasma and milk were lower than those of the parent SDM. Sulphate and glucuronide metabolites could not be detected in milk.

At high doses (45 mg/kg or more) and SDM plasma concentrations exceeding 20 μg/ml, a capacity limited metabolism of SDM to SCH₂OH was noticed, viz, asteady state concentration of SCH₂OH and a biphasic elimination pattern for SDM and SCH,OH in plasma and milk.

The mean ultrafiltrate ratios of the milk to plasma concentrations with respect to SDM, SCH₂OH, SOH, and N₄‐SDM were: 0.69, 0.22, 020, and 0.63, respectively.

The total amount of SDM and its metabolites recovered from the milk after milking twice daily over the whole experimental time was less than 2% of the applied dose.

A bioassay method allowed of detecting qualitatively SDM concentrations exceeding 0.2 μg/ml in plasma or milk. Withholding times for edible tissues and milk are suggested.     

Effect of β -glucanase and xylanase supplementation of barley- and rye-based diets on caecal microbiota of broiler chickens

1. The aim was to investigate the effect of grain type (barley or rye) and exogenous enzymes (β-glucanase or xylanase) on the composition of chicken caecal microbiota as examined by classical culturing and molecular techniques (fluorescent in-situ hybridisation (FISH) and terminal-restriction fragment-length polymorphism (T-RFLP)). 2. Plate counting revealed higher total numbers of anaerobic bacteria, lactic acid bacteria and yeasts in caecal contents of birds fed with rye-based diets than in birds fed with barley-based diets. 3. As assessed by FISH analysis, the most abundant bacterial groups in the broiler caeca were Clostridium coccoides-Eubacterium rectale followed by Bacteroides sp., Lactobacillus sp./Enterococcus sp., Bifidobacterium sp. and Enterobacteriaceae. For both cereal types, the enzyme supplementation significantly decreased the relative amount of Enterobacteriaceae. 4. The T-RFLP profiles indicated that the caecal microbiota of birds receiving rye-based diets was more diverse than that of birds fed on barley-based diets. 5. Irrespective of the method applied, the results indicate that the cereal type as well as the exogenous enzyme supplementation influence the microbiota in broiler chicken caeca, and may have the effect of reducing potentially pathogenic Enterobacteriaceae populations.     

Comparison and Correlation of Agronomic Characteristics and Fermentation Quality of Different Types of Hybrid Corn北大核心CSCD

In order to select the silage corn (Zea mays L.) hybrids suitable for planting in the northern part of Shanxi Province, the agronomic characteristics of 16 hybrid corn and the fermentation quality of silage prepared after castration were measured. The results showed that in agronomic characteristics, DJJ 26 had the highest plant height and ear height, but its stem diameter was the thinner. The green-leaf number ranked in the top three is TY168, QS 30 and GK516. For yields, DF26 had the highest yield. For ensiling characteristics, except for DH679, TY511, all hybrids were below 4. 20 for pH values. The significantly positive correlation was found between fresh grass yield and stem diameter, green-leaf number, stem weight, ear weight, leaf weight. The Lactic acid content of whole plant corn silage was positively correlated with green-leaf number. Therefore, the corn hybrids with thick stems, more green leaves and good panicle traits should be selected for silage use. The JD65 and TY168, GK516 and QS30 have good growth and fermentation performance, thereby, could be selected for silage corn in the northern part of Shanxi Province. © 2019 China Agricultural University. All rights reserved.     

Effects of altitude and variety on nutrient levels and epiphytes of oats北大核心CSCD

Oat crops are a major animal feed source in the Qinghai-Tibetan plateau and nearby areas. Typically，the crops are used for making silage rather than hay because of frequent rain at harvest in autumn. However，there is little data on how the yield，forage quality and levels of epiphytes that may affect silage quality of different oat varieties are affected by altitude. Therefore，four oat varieties（Longyan No. 3，Longyan No. 5，Baiyan No. 2 and Bayou No. 3） were planted in 8 localities forming an altitude gradient： Huangzhong （2295 m），Tianzhu （2797 m），Shandan （2860 m），Hezuo （2957 m），Haiyan （3052 m），Maqu （3474 m），Maqin （3765 m）and Chengduo （4217 m）. Measurements included crop yield and dry matter （DM），water soluble carbohydrate （WSC），crude protein （CP），neutral detergent fiber （NDF）and acid detergent fiber （ADF）contents，and counts of lactic acid bacteria （LAB），molds，yeasts and aerobic bacteria. It was found that there were significant altitude and variety effects on fresh yield，nutritional quality and microbial epiphyte counts. With increase in altitude，fresh yield，WSC，NDF and LAB counts increased（P<0.05），as much as 284. 00%，15. 49%，10.81% and 11.60% increment were observed at Chengduo site than that at Huangzhong，respectively；meanwhile DM，CP and yeast and mold counts were reduced by 15. 67%，36.27%，23.53% and 7.75% at Chengduo compared with Huangzhong site，respectively. Among the four tested varieties，Longyan No. 5 had the highest fresh yield （75605 kg·ha−1），WSC （201.4 g·kg-1 DM） and NDF （604. 2 g·kg-1 DM） at the Chengduo site，followed by Longyan No. 3. The highest CP （119.7 g· kg-1 DM） and mold counts （4.12 lg cfu·g-1 FM） were observed in Baiyan No. 2 at the Huangzhong site. Bayou No. 3 produced the highest LAB and yeast counts at Maqin and Chengduo sites. In general，Longyan No. 3 and Longyan No. 5 gave better performance at sites above 3000 m altitude；for sites below 3000 m，the four tested varieties were all found to be suitable for silage production. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Prevalence and incidence of Newcastle disease and prevalence of Avian Influenza infection of scavenging village chickens in Timor-Lesté

A longitudinal study to monitor prevalence and incidence of antibodies against Newcastle disease (ND) virus and prevalence of antibodies against Avian Influenza (AI) virus in scavenging village chickens was conducted in 20 villages within 4 districts of Timor-Lesté. A total of 3600 blood samples was collected from 1674 individual birds in 300 household chicken flocks during three sampling periods (December 2008-February 2009, March-May 2009, and June-August 2009). The mean interval between household visits was 101.6±1.9 days. None of the birds enrolled in the study was vaccinated against ND or AI. A haemagglutination inhibition (HI) test was used to determine antibody titres against ND virus and a competitive ELISA and HI tests were used to detect antibody against AI virus. The bird-level ND seroprevalence pooled across all samplings (adjusted for clustering by households) was 4.4% (95% CI 3.5-5.2). The bird-level ND seroprevalence in each of the three sampling periods (adjusted for clustering by household) was 3.0% (95% CI 2.0-4.0), 6.6% (95% CI 5.1-8.0) and 3.6 (95% CI 2.5-4.6), respectively. A total of 12.6% individual birds tested ND seropositive at least once over the total study period (95% CI 10.5-14.7). The flock-level ND seroprevalence (at least one bird tested had antibodies against ND virus) pooled across all samplings was 15.9% (95% CI 13.5-18.3). A total of 35.3% flocks had a minimum of one bird being ND seropositive at least once over the study period. The bird-level incidence rate for the period between the first and the second sampling and between the second and the third sampling was 5.6 (95% CI 4.1-7.5) and 0.5 (95% CI 0.5-3.8) per 10,000 bird-years-at-risk, respectively. A total of 1134 serum samples from the last sampling period between June and August 2009 was tested for antibodies against AI virus. Only 4 samples tested Influenza A positive, indicating a bird-level seroprevalence level for Influenza A of 0.4% (CI 0.0-0.7%). These Influenza A positive samples were further tested for HI antibodies against AI virus subtypes of H5N1, H5N3, H7N3 and H9N2, but all tested negative, suggesting that the influenza antibodies in those four birds resulted from exposure to low pathogenic AI viruses of different H subtypes. Our results indicate that village chickens in Timor-Lesté are exposed to ND virus; there was a higher risk of infection during the early months of 2009 than either immediately prior or subsequent to this. No evidence of infection of village chickens with H5, H7 or H9 AI viruses was detected in this study.     

Production benefits of the crossbreeding of indigenous and non-indigenous ducks—growing and laying period body weight and production performance

To evaluate different crosses and purebreds ducks in respect to various economic traits and to estimate different crossbreeding genetic parameters, a 3?×?3 complete diallel cross involving indigenous duck (DD), Khaki Campbell (KK) and White Pekin (WW) were used to produce three purebreds (DD, KK, WW) three crossbreds (DK, DW, KW) and three reciprocals (KD, WD, WK). A total of 609 ducklings produced were reared on deep litter and the females (316 in number) were evaluated for growing and laying period body weight along with the production performance traits. Different crossbreeding genetic parameters were estimated for different traits. All the traits in respect to body weight gain during growing and laying period and different production traits including laying house mortality rate showed significant (p?≤?0.05) difference between different genetic groups. In general, crossbreds perform better than the purebreds for most of the traits studied. General combining ability (GCA), specific combining ability (SCA) and reciprocal effect (RE) were significant (p?≤?0.01) for body weight and production traits. Egg weight showed significant (p?≤?0.01) difference in respect to GCA, SCA and RE for all the ages of measurement except RE for 30th week egg weight. Laying period mortality rate was only significant (p?≤?0.05) for SCA. Most of the crossbreds recorded heterosis rate in desirable direction for majority of the traits. Overall results revealed that the crossbreds perform well in respect to different traits than the purebreds and may be used to take advantage of heterosis. DW performs well in respect to majority of the traits measured and is of importance for commercial exploitation. Further, pure line selection with development of specialised sire and dam line followed by crossing may be of importance to enhance the performances in the crosses.