典型粪污处理模式下规模养猪场农牧结合规模配置研究Ⅰ.固液分离 液体厌氧发酵模式

不同粪污处理模式下畜禽粪便的养分损失存在较大差异,从而影响其后续地农田利用。固液分离-液体厌氧发酵模式是当前我国畜禽粪污处理的主要模式之一。研究粪污固液分离-液体厌氧发酵处理模式下规模养猪场农牧结合适宜规模配置对于减少畜禽粪便污染、促进畜牧业可持续发展具有重要意义。本研究根据猪群体结构比例、废弃物产生量及氮磷含量、废弃物处理利用过程中养分损失率以及作物氮磷钾需求量等资料,以存栏万头猪场为例,采用分步逐级计算的方法估算了典型粪便处理模式——固液分离-液体厌氧发酵下,规模养猪场废弃物完全消纳的不同种植模式农田匹配面积,并研究了基于作物养分需求的不同种植模式农田畜禽粪便承载量。结果表明:固液分离-液体厌氧发酵粪便处理模式,以沼液安全消纳为目标,万头猪场需要配置的最少农田面积分别为粮油作物地12.4~13.7 hm2,或茄果类蔬菜地14.2~17.9 hm2,或果树苗木地16.4~51.3 hm2。以有机肥和沼液全部在农田安全消纳为目标,万头猪场需要配置的最少农田面积分别为粮油作物地299.3~312.9 hm2,或茄果类蔬菜地145.1~179.0 hm2,或果树苗木地553.1~1 343.8 hm2。因此,规模养猪场应根据猪养殖数量及其周边农田面积,选择适宜的有机肥利用方式及种植作物类型,因地制宜,合理调控。     

施用猪粪对土壤Zn形态和菜心Zn含量的影响

采用盆栽试验的方法,研究施用猪粪对土壤和菜心Zn含量的影响,以为蔬菜安全施用畜禽粪便提供依据.结果表明,土壤全Zn、有效态Zn和菜心Zn含量均随猪粪施用量和施用茬数的增加而提高,连续2茬施用猪粪达到40g/kg时,土壤全Zn含量和菜心Zn含量分别达到266.42和21.03mg/kg,超过国家土壤质量二级标准(pH≤6...     

Analysis of the mouse high-growth region in pigs

In the mouse, homozygous animals for the high growth mutation show a 30–50% increase in growth without becoming obese. This region is homologous to the distal part of pig chromosome 5 (SSC5). A previous genome scan detected several quantitative trait loci (QTL) in this region for body composition and meat quality using a three generation Berkshire × Yorkshire resource family. In this study, the effects on swine growth, fat and meat quality traits of three genes previously identified within the mouse high growth region were analysed. The genes studied were CASP2 and RIPKI domain containing adaptor with death domain ( CRADD ), suppressor of cytokine signalling 2 ( SOCS2 ) and plexinC1 ( PLXNC1 ). In addition, the influence of two other genes located very close to this region, namely the plasma membrane calcium-transporting ATPase 1 ( ATP2B1 ) and dual specificity phosphatase 6 ( DUSP6 ) genes, was also investigated. Single nucleotide polymorphisms were identified and used to map these genes to the QTL region on SSC5. Results indicate significant associations between these genes and several phenotypic traits, including fat deposition and growth in pigs. The present study suggests associations of these genes with swine fat and growth related traits, but further studies are needed in order to clearly identify the genes involved in the regulation of the QTL located on SSC5.     

Histological and immunohistochemical evaluation of duodenal and colonic biopsies after oral bovine lactoferrin supplementation in beagle puppies

Lactoferrin is a natural compound in the milk of mammals and was shown to influence the intestinal micro‐flora and the immune system in mice, calves, dogs and man. The present study was carried out to investigate the effect of orally administered bovine lactoferrin (0, 30, 60 and 120 mg/kg DM feed) on the intestinal morphology and lymphocyte colonization in 36 motherless raised puppies. Endoscopic biopsies from duodenum and colon, taken in week 14, were scored histologically after staining with haematoxylin and eosin (H&E) and lymphocytes (CD3⁺, CD4⁺, CD8⁺) and plasma cells (IgA⁺, IgG⁺, IgM⁺) were enumerated after immunohistochemical staining by computer‐aided quantification. Histological scoring revealed no significant differences amongst the groups. IgG⁺ plasma cells were reduced (p < 0.05) in the lamina propria of the colon of the 30 and the 60 mg group. The number of CD8⁺ lymphocytes was higher (p < 0.05) in the epithelium of the colon of the lactoferrin groups. In conclusion, this study indicated only minimal effects of bovine lactoferrin on the population of selected immune cells in the gut mucosa of puppies. More investigations are needed to describe the impact of lactoferrin on the digestive physiology of puppies.     

Intestinal microbiota differentially affect brush border enzyme activity and gene expression in the neonatal gnotobiotic pig

To study microbial influence on intestinal development pertaining to nutrient digestion, two separate gnotobiotic experiments were performed, each with 16 piglets allocated to four treatment groups: germfree (GF), monoassociation with Escherichia coli, monoassociation with Lactobacillus fermentum or conventionalization with faecal bacteria (CV). Enzyme activity and gene expression of lactase phlorizin hydrolase (LPH) and aminopeptidase N (APN) were measured in isolated enterocytes, harvested on day 14, using specific substrates and quantitative PCR respectively. Enterocytes of CV pigs had reduced APN activity, but had increased gene expression relative to GF, making the specific activity:mRNA (A:G) ratio dramatically lower (p < 0.05). Similarly, LPH A:G ratio was significantly reduced (p < 0.05) in enterocytes of CV pigs as compared with GF. The results of co‐incubation of L. fermentum, E. coli and faecal bacteria with APN indicate a direct relationship between enzyme inactivation and specific A:G ratio in enterocytes. We conclude that enterocyte up‐regulation of APN expression occurs as either a direct response to microbial colonization or as a feedback mechanism in response to reduced enzyme activity through microbial degradation. This mechanism may play a role in ensuring effective competition of the host with the intestinal microbiota for available nutrients.     

Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli

The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ～10⁹–10¹⁰ CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.     

Validation of the QTL on SSC4 for meat and carcass quality traits in a commercial crossbred pig population

Porcine chromosome 4 harbours many quantitative trait loci (QTL) affecting meat quality, fatness and carcass composition traits, detected in resource pig populations previously. However, prior to selection in commercial breeds, QTL identified in an intercross between divergent breeds require confirmation, so that they can be segregated. Consequently, the objective of this study was to validate several QTL on porcine chromosome 4 responsible for meat and carcass quality traits. The experimental population consisted of 14 crossbred paternal half-sib families. The region of investigation was the q arm of SSC4 flanked by the markers S0073 and S0813. Regression analysis resulted in the validation of three QTL within the interval: Minolta a * loin, back fat thickness and the weight of trimmed ham. The results were additionally confirmed by factor analysis. Candidate genes were proposed for meat colour, which was the most evident QTL validated in this study.     

乙酸镁对氟烷基因杂合子育肥猪肌肉加工品质的影响

育肥猪屠宰前饲粮中短期添加乙酸镁,研究其对氟烷基因杂合子育肥猪肌肉加工品质的影响。选用体重相近的氟烷基因杂合子(HalNHaln)大长猪(大白猪×长白猪)36头随机分为2组,即对照组、乙酸镁组,每组18头。乙酸镁组在屠宰前5 d,基础日粮中添加镁1 500mg/kg(以乙酸镁形式),对照组饲喂基础日粮。试验表明:在猪屠宰前饲粮中短期添加1 500 mg/kg水平的镁对试验猪的平均日采食量没有明显影响(P>0.05);可以显著降低肌肉的滴水损失(P<0.05),提高猪肉的熟肉率,从而提高猪肉的加工品质。     

1例规模化猪场暴发高致病性繁殖与呼吸综合征（HPPRRS）与圆环Ⅱ型（PCV-2）混合感染的诊治

四川省邻水县的1个规模化猪场60-60日龄猪只430头相继暴发疲病,采集15头病猪血清样品和2头病死猪肺和脾脏组织病料,采用HPPRRSV RT—PCR试剂盒（军事兽医研究所涂长春教授惠赠）检测,结果是8份血清（占55．8％）和2份病料（100％）为阳性。同时,6份血清和2头病死猪肺和脾脏组织病料用PCV-2 PCR试剂盒（自制）检测,结果是3份血清（占50％）和2份病料（100％）为阳性;结果表明：该猪场暴发了HPPff,RSV和PCV2混合感染。     

Challenges posed to the traceability of weaner pigs following live auction

Objectives   To gather demographic data on live pig sales through a peri-urban saleyard in Camden, New South Wales, and to demonstrate the difficulties in tracing the subsequent movements of pigs, particularly weaner pigs.
Procedure   Records of pig sales held weekly at the Camden saleyards for the 2003/2004 and 2004/2005 financial years were analysed. Saleyard data on a number of variables were entered into a purpose-designed database. Distributions of pig sales according to pig class (weaner/porker/baconer/backfatter), purchaser type (butcher/non-butcher), and transaction type (cash/account) were determined.
Results   More weaners (3192 in 2003/2004 and 3940 in 2004/2005) were sold than any other class of pig, accounting for 45% of the total pigs sold during this period. During 2003/2004, 3802 pigs were bought by 329 non-butcher purchasers including 1631 weaners (43%) purchased by 153 non-butchers (47%). The majority of these non-butchers during the study period (86%) paid cash for their pigs and did not provide the necessary information to allow the end destination of pigs to be determined. Location data was available for all vendors but only 25% of purchasers.
Conclusions   This study highlights the challenges posed in tracing movement of pigs following sale by auction. A high proportion of weaners sold at this peri-urban saleyard would not have been slaughtered immediately. This study highlights the potential difficulties in tracing pig movements after sale, for disease control purposes. We recommend that legislation be amended requiring the identification of weaner pigs sold live at auction in all states of Australia and the recording of the property identification code of all vendors and purchasers of pigs sold live at auction.