Variability among sources and laboratories in nutrient analyses of corn and soybean meal. NCR-42 Committee on Swine Nutrition. North Central Regional-42

A cooperative research study involving members of a regional committee (North Central Regional Committee on Swine Nutrition [NCR-42]) was conducted to assess the variability in nutrient composition (DM, CP, Ca, P, Se, and amino acids) of corn and soybean meal from 16 sources (15 states, mostly in the Midwest) and to assess the analytical variability in nutrient assays among 22 laboratories (labs; 16 experiment station labs and six commercial labs). Corn samples were obtained from each participating station's feed mill during a 3-yr period (1989, 1990, and 1992), as were soybean meal samples during a 2-yr period (1989 and 1990). Both regular soybean meal (with hulls) and dehulled soybean meal were represented in the study. Samples were analyzed for DM and CP by all 22 labs, for Ca and P by 15 labs, for amino acids by 10 labs, and for Se by 6 labs. Each lab used its own analytical procedures. Samples of corn and soybean meal varied in their nutrient composition depending on the area of origin. The greatest variation among sources was in Se concentration, ranging from .02 to .29 mg/kg in corn and .08 to .95 mg/kg in soybean meal. Crude protein and lysine in corn were positively correlated, but the regression coefficient was low (r2 = .49). The relationship between CP and lysine for the two soybean meals combined was considerably stronger (r2 = .81). Lysine in corn increased by .018 percentage point and lysine in soybean meal (regular and dehulled combined) increased by .063 percentage point for each 1 percentage point increase in CP. Except for CP and Se, the analytical variability among labs was as great as, and in some cases greater than, the variability in nutrient composition among sources of corn and soybean meal. Within-lab analytical variability tended to be less than among-lab variability. Some labs performed certain analyses with considerably less variability and more accuracy than others.     

Effects of dietary valine concentration on lactational performance of sows nursing large litters. NCR-42 Committe on Swine Nutrition

A cooperative study, using 231 primiand multiparous crossbred sows from six experiment stations (IN, KS, MI, MN, ND, and OH), was conducted to determine the effects of elevating dietary valine concentration in corn-soybean meal diets on lactational performance of sows nursing large litters. Crossbred sows were fed diets containing a minimum of .60% lysine during gestation. Sows were allotted at farrowing to four dietary valine concentrations, .80, .95, 1.10, and 1.25%. Crystalline L-valine replaced cornstarch to maintain a constant ratio of corn:soybean meal across diets. Dietary lysine, provided by corn, soybean meal, and .15% crystalline L-lysine x HCl, was .90% in all diets. Sows were allowed ad libitum access to feed. Sows were weighed within 24 h after farrowing, and all litters were adjusted to > or = 10 pigs/litter by d 2 following farrowing. Average sow parity, number of pigs on d 2, and lactation length for the four treatments were, respectively, 2.3, 2.3, 2.3, 2.5; 10.9, 10.8, 10.8, 10.7; and 25.1, 24.5, 25.2, 25.0 d. The ADFI during lactation was 5.87, 5.77, 5.87, and 5.74 kg (P > .50); hence, valine intakes were 41, 48, 55, and 61 g/d (linear, P < .01). Lysine intake ranged from 51.5 to 52.7 g/d (P > .50). Sow weight after farrowing averaged 198 kg (P > .60). Overall pig survival to weaning was high (>92%), and the number of pigs weaned (10.1, 10.3, 10.3, 10.3) did not differ (P > .30) among treatments. Litter weaning weights (73.6, 73.6, 74.5, 72.6 kg), litter weight gains (55.1, 55.1, 56.0, 54.1 kg), sow weight change during lactation (-4.9, -5.4, -4.8, -6.3 kg), and return-to-estrus interval (7.5, 6.4, 6.9, 8.2 d) were not affected (P > .30) by dietary valine. There were no station x treatment interactions (P > .50). These results indicate no benefit of elevated dietary valine for lactating sows nursing > or = 10 pigs and consuming a corn-soybean meal diet containing .90% lysine and .80% valine.     

Effect of room temperature and dietary amino acid concentration on performance of lactating sows. NCR-89 Committee on Swine Management.

Mixed-parity sows (n = 267) from five research stations were used to investigate whether a reduction of excess dietary amino acids would improve feed intake and performance of lactating sows experiencing heat stress. Experimental treatments included effects of room temperature (warm or hot) and diet (adequate protein [AP] or low protein [LP]). The corn-soybean meal AP diet was formulated to contain 16.5% CP, .8% lysine, and .67% digestible lysine. The LP diet was formulated to contain 13.7% CP, .76% lysine, and .66% digestible lysine using corn, soybean meal, and synthetic lysine. Feed intake during gestation was standardized at 1.8 kg x sow(-1) x d(-1). At parturition, litter size was adjusted to no fewer than nine pigs. Mean high temperature in the warm and hot rooms was 20.4 and 29.2 degrees C and mean low temperature was 17.7 and 27.1 degrees C, respectively. The hot environment reduced (P < .01) feed intake of sows (4.19 vs 6.38 kg/d) during lactation, weaning weight of sows (176.2 vs 193.6 kg), percentage of sows displaying estrus (79.2 vs 93.4%) by d 15 postweaning, and litter growth rate (1.74 vs 2.11 kg/d) and increased (P < .01) respiration rate of sows on d 10 postpartum (71.9 vs 36.5 breaths/min) compared with the warm environment. Litter size and backfat loss of sows were not affected by treatments. No significant diet x room temperature interactions were observed for voluntary feed intake, body weight loss, backfat loss, or respiration rate of sows. Litter growth rate was depressed by feeding the LP diet in the warm room but was improved by feeding the LP diet in the hot room (warm-AP, 2.17; warm-LP, 2.05; hot-AP, 1.71; hot-LP, 1.77 kg/d; P < .05). Reduction of dietary crude protein combined with supplementation of crystalline lysine to reduce concentrations of excess dietary amino acids did not significantly reduce heat stress of sows, but it did support slight improvements in weight gain of litters nursing heat-stressed sows.     

猪的膳食纤维营养与应用概述

膳食纤维对不同生长阶段猪营养作用表现不同。日粮中添加膳食纤维有助于仔猪肠道发育并维持肠道健康和微生态平衡,减少仔猪断奶应激,缓解仔猪断奶腹泻。肥育猪日粮中添加膳食纤维,可增强后肠发酵,减少粪氮的排放量,降低环境污染,也可节约常规原料。妊娠母猪日粮中添加膳食纤维可减少限饲应激和便秘的发生,并且能改善母猪的繁殖性能,促进哺乳仔猪生长。本文主要综述了膳食纤维的定义、理化性质、分析体系及其在猪营养上的应用,以期为实际生产提供一定的指导意义。     

Soybean hulls, wheat middlings, and corn gluten feed as supplements for cattle on forage-based diets.

Soybean hulls, wheat midds, and corn gluten feed are viable alternative supplements for forage-fed cattle. All three result from the processing of major Unites States agricultural crops, so large supplies are available. Their value is better for ruminant animals than for monogastrics because they contain digestible fiber components. These byproducts are widely available throughout the Unites States and will generally be more economical than traditional feed grains or commercial feeds when used appropriately as supplements to forage-based diets. Knowledge about the composition of base forage must be used in planning supplementation strategies because base forages vary in protein and mineral content [9]. Soybean hulls alone may be a good selection in situations in which forages are adequate or high in protein. In situations where forage is marginal or deficient in protein, wheat midds, corn gluten feed, or a mix of soybean hulls and corn gluten feed might be most desirable. All three feeds can be variable in nutrient composition, so they should be analyzed to ensure a balanced nutrient level in diets. Soybean hulls are especially variable in crude protein content and should always be analyzed when forages are marginal or deficient in protein. Despite the fact that published energy levels are substantially lower, research has shown that soybean hulls and wheat midds have a value comparable to corn and soybean meal in forage-based diets. Corn gluten feed has also been comparable to corn and soybean meal in most reports but is closer in value to its published energy levels. In general, results with soybean hulls have been surprisingly good and consistent, whereas responses to wheat midds and corn gluten feed supplementation have been more variable and sometimes disappointing. Feeding rates for soybean hulls can range from low to extremely high depending on forage availability and desired performance. Wheat midds should be limited in most situations to 50% of the expected dry matter intake because of their rapidly digested starch content. Corn gluten feed should be limited to approximately 50% of expected dry matter intake because of its high sulfur content. Several research groups are currently evaluating self-feeding programs for these byproducts, and while the potential for health and production problems exist, results have been encouraging in most cases. Self-feeding would reduce the labor costs of hand feeding and could provide backgrounders with a program to expand cattle numbers on a limited land base.     

Effects of restricted and ad libitum intake of diets containing wheat middlings on site and extent of digestion in steers

A 5 x 5 Latin square design was used to determine the effects of restricted and ad libitum intake of diets containing wheat middlings on the site and extent of digestion compared to ad libitum intake of a corn-based diet and ad libitum intake of chopped alfalfa hay. Five ruminally and duodenally cannulated Angus steers (519 +/- 41.5 kg BW) were used to compare five dietary treatments. The five treatments were as follows: ad libitum access to a corn-based finishing diet (control), the control diet with 25 percentage units of the corn and soybean meal replaced with wheat middlings offered ad libitum (WM), the WM diet restricted to 75% of predicted ad libitum intake (RWM), the RWM diet with wheat middlings replaced with ammoniated wheat middlings (RNWM), and ad libitum access to a chopped alfalfa hay diet. Although RWM steers were fed to consume 75% of ad libitum intake, RWM steers consumed 15.5% less DM than WM. Steers fed ad libitum hay consumed 28.6, 31.7, and 37.2% less (P < 0.01) DM, OM, and nitrogen than RWM steers. No differences in apparent or true ruminal digestibility were observed among steers fed the control vs WM, WM vs RWM, RWM vs RNWM, or RWM vs hay diets. However, the steers fed the hay diet had 32.5, 33.4, and 36.9% lower (P < 0.01) apparent total tract digestibilities of DM, OM, and N than those fed the RWM diet. Average ruminal pH was lower (P < 0.01) for control steers than those fed the WM diet and for those fed RWM compared to the hay diet. The acetate:propionate ratio was higher for cattle fed hay vs the RWM diet. Microbial DM and OM flow to the small intestine was higher (P < 0.02) for steers fed the RWM diet than those fed the hay diet. In addition, bacterial N flow to the small intestine was higher (P < 0.01) for cattle receiving the RWM diet than the hay diet. Feeding diets containing 25 percentage units of wheat middlings at 75% ad libitum intake had no effect on ruminal digestibility.     

微量元素铬对猪的营养研究进展

有机铬是一种极有前景的新型营养添加剂,对生长猪和繁殖母猪可产生有益的生物学效应,在日粮中一般补充０．２ｍｇ／ｋｇ的有机铬可以显著改善猪的饲料利用率、胴 组成及繁殖性能。本文就铬的生物学功能、铬对猪的抗应激能力和免疫力的影响、对猪的营养进展和应用前景作一综述。     

猪禽氨基酸营养和代谢研究进展

<正>氮、磷是重要的环境污染源,因此减少动物排泄物中的氮、磷是控制环境污染问题的有效途径之一。目前,遗传学家已经成功培育出新一代能更加有效生产动物蛋白的猪禽品种,接下来,营养学家需要设计出能充分发挥其遗传潜力的饲养方案,以     

猪可代谢营养评定新体系研究进展

在动物体内,葡萄糖具有重要的生理作用。糖代谢在动物能量代谢中处于重要的核心地位。现行营养评价指标体系大多建立在能量指标基础上,忽视了糖代谢在能量代谢中的核心地位,割裂了能量代谢和物质代谢的紧密联系,具有很强的表观性和局限性,有待于进一步发展。本文介绍了以代谢葡萄糖(MG)、代谢蛋白质(MP)和代谢生脂物质(MLS)为基础的物质指标体系的理论框架及其在猪的营养评价上的研究进展,为构建猪可代谢营养评定新体系进行了初步的探索。     

Apparent digestibility of amino acids, gross energy and starch in corn, sorghum, wheat, barley, oat groats and wheat middlings for growing pigs

Apparent nutrient digestibilities of yellow-dent corn, low-tannin sorghum, hard red winter wheat, barley, oat groats and wheat middlings were determined near the end of the small intestine and over the total digestive tract of growing pigs. Gross energy digestibilities for corn, sorghum and oat groats were similar; wheat had a slightly lower (P less than .05) digestibility, followed by barley (P less than .05), with wheat middlings being the least (P less than .05) digestible. About 7% of the gross energy in corn, sorghum, wheat and oat groats was digested in the large intestine, compared with 11% for barley and 17% for wheat middlings. The starch in all products was essentially 100% digestible by the end of the small intestine. Ileal amino acid digestibilities tended to be highest for wheat and oat groats, followed by corn, sorghum, barley and wheat middlings. The range in ileal digestibilities was 73.8 (sorghum) to 84.2% (wheat) for lysine, 69.6 (corn) to 81.4% (wheat) for tryptophan and 63.4 (wheat middlings) to 77.9% (oat groats) for threonine. Amino acid digestibilities determined over the total tract were generally higher than ileal digestibilities; however, values for lysine, methionine and phenylalanine were generally lower, indicating a net synthesis of these amino acids in the large intestine.     

Summary of the first round analyses of the Third International Workshop on Swine Leukocyte Differentiation Antigens.

The reactivity of 155 monoclonal antibodies submitted to the Third International Workshop on Swine Leukocyte Differentiation Antigens, together with 41 internal standards, was analysed by flow cytometry on 29 different pig cell targets as well as two human cell targets as a means of establishing suitable panels of monoclonal antibodies for more detailed clustering analyses by the various subsections of the workshop. Results were collected either without further gating, with gating based on FS/SS characteristics or with gating based on the co-expression of a reference antibody in two-colour flow cytometry. The CD or SWC reactivity of the internal standards had been established in previous workshops. Data sets were subsequently analysed by statistical clustering using the Leucocyte Typing Database IV software. The resulting 18 cluster groups were allocated to the appropriate second round sections of the workshop, after reviewing the overall cellular reactivity of each cluster as well as the specificity of known standards which clustered in a group.     

干酒糟及其可溶物的营养价值及其在猪生产上的应用

干酒糟及其可溶物(DDGS)是乙醇生产工业副产物,随着生物能源的应用增加,DDGS产量上升。DDGS最先用于反刍动物生产中,近年来,也有很多报道将DDGS用于猪、鸡等单胃动物生产行业。本文从DDGS的生产工艺、营养组成、对猪的营养价值及其在猪生产上的应用现状以及改进措施等几个方面对近十年来国外学者在DDGS上的研究进行了综述。虽然DDGS能替代部分豆粕和玉米用于猪生产中,但由于其质量的不稳定、蛋白质品质的低下和粗纤维含量过高影响了其大量使用。通过过筛、发酵、加酶、不同原料组合使用等方法能扩大并提高DDGS在养殖行业的应用。     

Variability in mixing efficiency and laboratory analyses of a common diet mixed at 25 experiment stations

An experiment involving 25 experiment stations in the North Central and Southern regions (NCR-42 and S-288, respectively) was conducted to assess the degree of uniformity of diet mixing among stations and to assess the variability among station laboratories in chemical analysis of mixed diets. A fortified corn-soybean meal diet was mixed at each station using a common diet formula (except for vitamin and trace-mineral additions). The diet was calculated to contain 14% crude protein (CP), 0.65% Ca, 0.50% P, and 125 ppm Zn (based on 100 ppm added Zn). After mixing, samples were collected from the initial 5% of feed discharged from the mixer, after 25, 50, and 75% was discharged, and from the final 5% of discharged feed. The five samples were sent to the University of Kentucky, finely ground, and divided into subsamples. Each set of five subsamples from each station was distributed to three randomly selected stations for analysis of CP, Ca, P, and Zn (i.e., each station analyzed five diet sub-samples from three other stations). In addition, two commercial and two station laboratories analyzed composites of the five subsamples from each of the 25 mixed diets. Based on the laboratories that analyzed all diets, means were 13.5, 0.65, and 0.52%, and 115 ppm for CP, Ca, P, and Zn, respectively. Ranges of 11.8 to 14.6% CP, 0.52 to 0.85% Ca, 0.47 to 0.58% P, and 71 to 182 ppm of Zn were found among the 25 diet mixes. The coefficients of variation among the 25 diet samples for CP, Ca, P, and Zn were 4.3, 9.3, 4.1, and 17.4%, and among the 25 laboratories were 3.6, 12.5, 10.7, and 11.1%, respectively. Overall analyses of the five sub samples were, respectively, CP: 13.4, 13.6, 13.4, 13.5, and 13.4% (P < 0.06); Ca: 0.66, 0.67, 0.67, 0.66, and 0.67%; P: 0.50,0.51,0.51,0.50, and 0.50%; and Zn: 115, 116, 112, 113, and 120 ppm (P < 0.001). Diets were not uniformly mixed at all stations (station x sample No. was P < 0.08 for Ca and P < 0.01 for CP, P, and Zn). Among stations, the range of the five samples, expressed as a percentage of the mean and averaged for CP, Ca, P, and Zn, varied from +/- 1.1% (i.e., 98.9 to 101.0%) to +/- 12.9% (84.6 to 110.4%), with an overall average of +/- 5.2%. Neither type nor volume of mixers was related to mixing uniformity. The results suggest that uniformity of diet mixes varies among experiment stations, that some stations miss their targeted levels of nutrients (especially Zn), and that the variability among experiment station laboratories in analysis of dietary Ca, P, and Zn in mixed diets is quite large.     

冬季发酵床养殖模式对猪舍环境及猪生产性能的影响

研究冬季发酵床养猪模式对猪舍环境、猪生产性能及免疫性能的影响.试验选用60头三元杂交断奶仔猪,分为两个处理,每处理5个重复,每重复6头猪.对照组为传统的水泥地面猪舍养殖模式,试验日粮为基础日粮+10%杆菌肽锌20mg/kg与10%硫酸粘杆茵素20mg/kg;试验组为发酵床猪舍养殖,试验日粮为基础日粮+O.1%日本酵素.测试指标为猪舍温度、相对湿度、悬浮颗粒浓度、氨气浓度、猪料肉比、平均日增重及血清IgA、IgM、IgG浓度.试验时间106d.结果显示,与对照组相比,试验组显著提高了猪舍温度(P<0.05),极显著降低了猪舍氨气和悬浮颗粒浓度(P<0.01),对猪舍相对湿度无显著影响;试验组显著提高了平均日增重、饲料转化率及血清IgA、IgG浓度(P<0.05),对血清IgM浓度无显著影响.试验表明冬季发酵床养猪模式可改善猪舍环境,提高猪的生产性能与免疫性能,优于水泥地面养殖模式.     

Effects of lactational status on forage intake, digestibility, and particulate passage rate of beef cows supplemented with soybean meal, wheat middlings, and corn and soybean meal

Sixteen mature, lactating (453 kg) and 16 nonlactating (487 kg) Hereford and Angus x Hereford cows were used to determine effects of different dietary supplements and lactational status on forage intake, digestibility, and particulate passage rate. Supplement treatments and amounts fed (kg/d) were as follows: control, 0; and equal daily amounts of CP from soybean meal (SBM), 1.36; wheat middlings (WM), 3.41; or a blend of corn and soybean meal (corn-SBM; 22% corn and 76% SBM), 3.41. Cows were fed supplements at 0800 and had ad libitum access to prairie hay (4.9% CP) in stalls from 0800 to 1100 and from 1300 to 1600 for three 17-d periods. Lactational status and supplement type did not interact (P greater than .50) for hay DMI, DM digestibility, or particulate passage rate. Cows fed SBM ate more hay DM (P less than .01) and had greater hay DM digestibility (P less than .01) than did cows in other treatment groups. Average hay DMI (kg/100 kg of BW) was 1.95, 2.16, 1.94, and 1.89, and hay DM digestibility was 52, 61, 55, and 53% for control, SBM, WM, and corn-SBM supplements, respectively. Total diet DM digestibility was increased by supplementation (P less than .01), but no differences (P greater than .18) were observed among supplements. Lactating cows ate more (P = .13) hay DM (2.11 vs 1.87 kg/100 kg of BW) and had greater (P less than .05) fecal output (4.6 vs 4.3 kg/d) than did nonlactating cows. Dry matter digestibility and particulate passage rate were not affected (P greater than .35) by lactational status.(ABSTRACT TRUNCATED AT 250 WORDS)     

冬季发酵床养殖模式对猪舍环境及猪生产性能的影响

研究冬季发酵床养猪模式对猪舍环境、猪生产性能及免疫性能的影响。试验选用60头三元杂交断奶仔猪,分为两个处理,每处理5个重复,每重复6头猪。对照组为传统的水泥地面猪舍养殖模式,试验日粮为基础日粮+10%杆菌肽锌20mg/kg与10%硫酸粘杆菌素20mg/kg;试验组为发酵床猪舍养殖,试验日粮为基础日粮+0.1%日本酵素。测试指标为猪舍温度、相对湿度、悬浮颗粒浓度、氨气浓度、猪料肉比、平均日增重及血清IgAI、gM、IgG浓度。试验时间106d。结果显示,与对照组相比,试验组显著提高了猪舍温度(P<0.05),极显著降低了猪舍氨气和悬浮颗粒浓度(P<0.01),对猪舍相对湿度无显著影响;试验组显著提高了平均日增重、饲料转化率及血清IgAI、gG浓度(P<0.05),对血清IgM浓度无显著影响。试验表明冬季发酵床养猪模式可改善猪舍环境,提高猪的生产性能与免疫性能,优于水泥地面养殖模式。     

Effects of dietary wheat middlings, distillers dried grains with solubles, and choice white grease on growth performance, carcass characteristics, and carcass fat quality of finishing pigs

Two experiments were conducted to evaluate the effects of adding combinations of wheat middlings (midds), distillers dried grains with solubles (DDGS), and choice white grease (CWG) to growing-finishing pig diets on growth, carcass traits, and carcass fat quality. In Exp. 1, 288 pigs (average initial BW = 46.6 kg) were used in an 84-d experiment with pens of pigs randomly allotted to 1 of 4 treatments with 8 pigs per pen and 9 pens per treatment. Treatments included a corn-soybean meal-based control, the control with 30% DDGS, the DDGS diet with 10% midds, or the DDGS diet with 20% midds. Diets were fed in 4 phases and formulated to constant standardized ileal digestible (SID) Lys:ME ratios within each phase. Overall (d 0 to 84), pigs fed diets containing increasing midds had decreased (linear, P ≤ 0.02) ADG and G:F, but ADFI was not affected. Feeding 30% DDGS did not influence growth. For carcass traits, increasing midds decreased (linear, P < 0.01) carcass yield and HCW but also decreased (quadratic, P = 0.02) backfat depth and increased (quadratic, P < 0.01) fat-free lean index (FFLI). Feeding 30% DDGS decreased (P = 0.03) carcass yield and backfat depth (P < 0.01) but increased FFLI (P = 0.02) and jowl fat iodine value (P < 0.01). In Exp. 2, 288 pigs (initial BW = 42.3 kg) were used in an 87-d experiment with pens of pigs randomly allotted to 1 of 6 dietary treatments with 8 pigs per pen and 6 pens per treatment. Treatments were arranged in a 2 × 3 factorial with 2 amounts of midds (0 or 20%) and 3 amounts of CWG (0, 2.5, or 5.0%). All diets contained 15% DDGS. Diets were fed in 4 phases and formulated to constant SID Lys:ME ratios in each phase. No CWG × midds interactions were observed. Overall (d 0 to 87), feeding 20% midds decreased (P < 0.01) ADG and G:F. Pigs increasing CWG had improved ADG (quadratic, P = 0.03) and G:F (linear, P < 0.01). Dietary midds or CWG did not affect ADFI. For carcass traits, feeding 20% midds decreased (P < 0.05) carcass yield, HCW, backfat depth, and loin depth but increased (P < 0.01) jowl fat iodine value. Pigs fed CWG had decreased (linear, P < 0.05) FFLI and increased (linear, P < 0.01) jowl fat iodine value. In conclusion, feeding midds reduced pig growth performance, carcass yield, and increased jowl fat iodine value. Although increasing diet energy with CWG can help mitigate negative effects on live performance, CWG did not eliminate negative impacts of midds on carcass yield, HCW, and jowl fat iodine value.     

消费者对非洲猪瘟认知情况及生猪产品消费意愿的调查分析

本研究旨在调查非洲猪瘟全国性爆发背景下普通消费者对非洲猪瘟基本情况的认知以及对生猪产品消费意愿的变化,从而为相关部门和生猪行业从业者提供消费端数据,作为政策制订及科普宣传的参考依据。本次调查采用自行设计的问卷,根据便利抽样法,共调查来自全国不同省市的普通消费者280人。结果表明,对非洲猪瘟是否人畜共患问题的正确认识率为42.5%,仅有36.4%和30.4%的消费者明确表示非洲猪瘟不会降低他们对生鲜猪肉和其他生猪产品的购买意愿。不同年龄、学历、地区、职业和家庭成员数量显著影响消费者对非洲猪瘟的认知情况和对生猪产品的消费意愿。加强针对高中以下文化水平、产业工人和无业者、家庭成员在5人及以上和40岁以下消费者群体的科普宣传力度,可能会对重塑现阶段消费者对生猪产品的消费信心、拉动其消费意愿起到一定的积极作用。     

某猪场猪瘟病例的综合诊断及病原基因分析

2017年3月山东省莱芜市某猪场保育猪群发生以高热(40.8~41.5℃)、精神高度沉郁、食欲不振、皮肤出血潮红及耳尖发绀为主要症状的急性热性传染病。为明确引起此次疫情的致病因素,对患病猪进行了病理剖检、组织病理学检查、分子生物学检测、病毒分离与鉴定,对分离病毒进行了E2基因的分子克隆测序及同源性比对,最终确定该病由猪瘟病毒感染引起,并分离到1株猪瘟病毒(SDLW2017)。该病毒株E2基因全长1119个碱基(nt),共编码373个氨基酸(aa);相似性分析表明,SDLW2017分离株与其它参考株的核苷酸相似性介于82.1%~96.3%,氨基酸相似性介于88.5%~97.6%,与1.1亚群HCLV株的核苷酸和氨基酸相似性最低,分别为82.1%和88.5%,而与2.1亚群参考株的核苷酸和氨基酸相似性较高,分别为91.8%~96.3%和95.2%~97.6%,其中与2.1b亚型参考株(GXWZ02)的相似性最高,分别为96.3%和97.6%。