Effects of administration of antimicrobials in feed on growth rate and feed efficiency of pigs in multisite production systems

OBJECTIVE: To evaluate effect of various regimens for administration of antimicrobials in feed on growth rate and feed efficiency (feed/gain) of pigs in multisite production systems. DESIGN: Controlled trial. ANIMALS: 24,099 growing pigs in 3 multisite production systems. PROCEDURE: 10 trials involving various regimens for administration of antimicrobials in feed were evaluated. Trial 1 compared effects of 2 antimicrobial regimens on finishing pig performance. Trials 2 through 10 compared growth rate and feed efficiency of nursery and finishing pigs given antimicrobials in feed with values for control pigs not given antimicrobials. RESULTS: In trial 1, no significant differences were observed between the 2 antimicrobial regimens. In the remaining trials, growth rate of nursery pigs fed antimicrobials was significantly improved, compared with growth rate of control pigs. However, growth rate of finishing pigs and feed efficiency of nursery and finishing pigs were not significantly improved by adding antimicrobials to the feed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of antimicrobials in the feed to promote growth should be limited to the nursery phase in multisite pig production systems. Use of antimicrobials in the feed of finishing pigs should be limited to therapeutic applications in which a diagnosis of bacterial infection susceptible to the antimicrobial to be used has been confirmed.     

Effects of sperm pretreatment on efficiency of ICSI-mediated gene transfer in pigs

Intracytoplasmic sperm injection (ICSI)-mediated gene transfer has recently been shown to be an effective technique for producing transgenic pigs; however, the types of sperm pretreatment having the most beneficial effects on post-ICSI embryogenesis or transgenic efficiency have not been clarified. In the present study, we performed ICSI-mediated gene transfer using pig sperm subjected to various pretreatments and determined the developmental potential of sperm-injected oocytes and introduction efficiency of exogenous DNA. Embryos were then transferred to recipient pigs to confirm gene transfer efficiency during the fetal period. When ICSI was performed using unfrozen sperm heads with tails removed by piezo-pulse, the rates of blastocyst formation (14.2%, 17/120) and transgene (EGFP) expression (11.8%, 2/17) were both low. When unfrozen sperm heads were used that were removed by sonication, EGFP expression efficiency (11/21, 52.4%) improved significantly (P<0.05). Pretreatment of unfrozen sperm with a surfactant or acrosomal reaction did not further improve the rates of blastocyst formation and EGFP expression. However, use of the heads of sperm frozen-thawed with or without a cryoprotective agent resulted in rates of blastocyst formation and EGFP expression that tended to be generally high (23.0%, 14/61-33.8%, 26/77 and 42.9%, 6/14-66.7%, 10/15). A total of 219 in vitro matured oocytes were fertilized by ICSI-mediated gene transfer using the heads of frozen-thawed sperm and then transferred into two recipient pigs. Seven fetuses were obtained, and EGFP expression and integration of the transgene (10-30 copies) were confirmed in two of the seven fetuses. Use of unfrozen sperm thus confers no advantages on ICSI-mediated gene transfer, and although further investigations are needed, frozen-thawed sperm heads appear to be useful in ICSI-mediated gene transfer.     

不同赖氨酸蛋白质比例对肥育猪氮利用效率的影响

试验选用5头平均体重为60.5kg的杜长大三元杂交猪,研究日粮中赖氨酸与粗蛋白质的比例对肥育猪氮利用效率的影响。日粮中赖氨酸的含量固定为0.8%,按照赖氨酸与粗蛋白质的比例(即4.6%、5.0%、5.6%、6.1%、6.6%)分为5个处理组,采用5×5拉丁方设计。试验结果表明:①赖氨酸与粗蛋白质的比例对粪氮的含量没有影响(P>0.05);②赖氨酸与粗蛋白质的比例对尿氮的含量影响显著(P<0.05);尿氮的含量随氮的摄入量的增加而增加;③氮的沉积和氮的利用效率在赖氨酸与粗蛋白质的比例为5.0%时最大,氮的存留量随日粮粗蛋白质水平的增加而增加(P<0.05),但是赖氨酸与粗蛋白质的比例对干物质和氮的消化率没有影响。     

发酵蛋白饲料对生长育肥猪生产性能和猪肉品质的影响

本试验探讨了在日粮中使用发酵蛋白原料替代普通蛋白原料对生长育肥猪生产性能和猪肉品质的影响。结果表明,以发酵豆粕、发酵棉粕为主要蛋白原料的育肥猪无抗饲料配方产品与常规饲料相比,能显著提高育肥猪末重及平均日增重;能使每头猪养殖增收78.72元,提高毛利33.98%;能显著降低猪肉剪切力和滴水损失,提高猪肉氨基酸水平,改善了肉品质,提高了猪肉营养。     

Effects of acute asphyxia at birth on subsequent heat production capacity in newborn pigs

The effect of acute asphyxia at birth on subsequent ability to produce heat was investigated in 30 newborn pigs. A model of experimentally induced asphyxia consisting of the prevention of breathing within the first four minutes of life was used. Blood was sampled from an umbilical artery catheter within the first 75 minutes of life for blood gas, pH, glucose, lactate and catecholamine analysis. After the treatment and 24 hours later, heat production capacity, shivering intensity and rectal temperature were measured 10 degrees C below thermoneutrality. Effects on blood gas parameters were severe but transient whereas alterations in carbohydrate metabolism were maintained during the first 75 minutes (P < 0.05). Acute asphyxia at birth induced only minor alterations of thermoregulatory abilities during the first day of life: rectal temperature was lower one hour after birth (P < 0.05) and the postnatal increase in heat production capacity was less pronounced than in controls. It is suggested that the lower viability usually reported for piglets suffering from asphyxia during delivery is most likely to result from reduced vigour and colostrum intake, as well as altered carbohydrate metabolism early after birth.     

日粮中添加乳清粉和膨化豆粕对断奶仔猪生产性能影响

选择30日龄断奶三元杂交仔猪(杜×长×大)64头。随机分成对照组、Ⅰ、Ⅱ、Ⅲ组,对照组饲以基础日粮,试验Ⅰ组日粮以膨化豆粕替代普通豆粕,试验Ⅱ组由3%的乳清粉替代3%的豆粕。试验Ⅲ组中膨化豆粕替代普通豆粕同时由3%的乳清粉替代3%的膨化豆粕。试验结果:对照组培育仔猪需46d,试验Ⅰ组(膨化豆粕组)培育仔猪需40d,试验Ⅱ组(乳清粉组)培育仔猪需43d,试验Ⅲ组(膨化豆粕+乳清粉组)培育仔猪需39d;平均日增重试验Ⅱ组显著高于对照组(P<0.05),试验Ⅰ、Ⅲ组极显著高于对照组(P<0.01),试验Ⅲ组极显著高于Ⅱ组(P<0.01)、显著高于试验Ⅰ组(P<0.05);饲料利用率试验Ⅲ组最高,对照组饲料利用率最差;腹泻率试验Ⅰ组下降了38.13%,试验Ⅱ组下降了34.63%,试验Ⅲ组下降了47.08%。结果表明利用膨化大豆或乳清粉等优质蛋白。调整日粮结构,可显著降低TI等抗营养因子和抗原物质的含量,减少腹泻率,提高生长性能。     

Modeling the efficiency of phosphorus utilization in growing pigs

Microbial phytase has been used to reduce P excretion from swine to mitigate environmental pollution. The objective of the study was to quantify the effect of feeding a low-P phytase-supplemented diet on growth and P utilization in growing pigs using mathematical models. A total of 20 weaned piglets (BW = 6.5 kg) housed in metabolism cages were randomly assigned to a standard diet (STD) or P-amended diet containing reduced P content and supplemented with phytase (AMN) with 10 pigs/diet. Body weight and feed consumption were recorded weekly so complete growth and cumulative P intake (cPI) curves could be modeled. A function with fixed point of inflexion (Gompertz) and a variable point of inflexion (generalized Michaelis-Menten) were considered in determining bioequivalence by analyzing BW vs. age relationships, whereas the monomolecular function was used to describe BW vs. cPI. All functions were incorporated into a nonlinear mixed effects model, and a first-order autoregressive correlation structure was implemented to take into account repeated measures. There was no difference between the 2 groups in final BW when the Gompertz equation was fitted (176 vs. 178 kg with SE of 7 kg for the STD and AMN, respectively) or the rate parameter (0.0140 vs. 0.0139 with SE of 0.0004 for the STD and AMN, respectively). The generalized Michaelis-Menten equation also showed a similar trend. When BW was expressed as a function of cPI the derivative with respect to cPI represented P efficiency, so it was possible to analyze the expected difference of the 2 diets in using P for BW gain and express it as a continuous function of cPI. The analysis showed through the entire growth period the difference in P efficiency was different from zero. On average, 56 g of supplemented inorganic P was consumed by a pig fed the AMN to reach market weight. In contrast, 309 g of supplemented inorganic P was consumed by the group fed the STD to reach similar BW. It would depend on other factors, but feeding pigs the AMN can result in economic benefit. Pigs fed the AMN excreted 19% less P compared with those fed the STD. In conclusion, nonlinear mixed model analysis (with repeated measures) was suitable for growth and efficiency analysis and showed that pigs fed the AMN consumed less than 20% of the inorganic P and performed as well as those fed the traditional inorganic P supplemented diet. The implications for mitigating P pollution, especially in areas where P loading is already problematic, are substantial.     

吡啶甲酸铬对生长猪生产性能和组织中铬残留的影响

选用96头体重(24.67±0.36)kg,公母各半达兰猪,随机分为4组,每组4个重复,每个重复6头。对照组饲喂基础日粮,3个试验组分别添加200、400μg/kg和800μg/kg吡啶甲酸铬(以铬计)。另外,选用8头体重(24.98±0.56)kg达兰猪,随机分为2组,添加1600μg/kg和3200μg/kg吡啶甲酸铬(以铬计),试验期28d。结果表明,添加200～800μg/kg吡啶甲酸铬对猪平均日增重和饲料转化效率无显著影响(P>0.05),但可提高饲料采食量,800μg/kg处理组的采食量显著高于其他3个处理组(P=0.01)。添加200～3200μg/kg吡啶甲酸铬猪组织中铬残留量为0.08～0.35mg/kg。     

Model calculations on the economic efficiency of sheep production

The answers to the questionnaire by the Commission on Sheep and Goat Production show quite large differences in the price relationships, particularly between meat and wool.It is at first shown from model calculations, how the optimum duration of using the ewes changes with a change of the relationship between mutton price and lamb meat price. In all cases, in which mutton is very cheap in comparison with lamb meat, a longer utility period is generally more efficient than a shorter one and vice versa (Fig.1).The relative importance of lamb carcases of different weight, in relationship to varying concentrate costs shows according to the conditions given in the model that when the price per kg meat is equal regardless of the carcase weight, that a 25 kg carcase is more efficient than producing a 20 kg carcase. On the other hand, if the meat of a 25 kg carcase is only valued at 90% of that of the 20 kg carcase, then the 20 kg carcase is preferable (Fig.2).Using the formula formerly developed for meat production and now expanded for other purposes 64 000 model calculations were made. The change of efficiency through changing of wool price, through increasing the level of fertility, through altering of working time and cost per hour as well as other factors, was illustrated by means of a few examples (Fig.3 and 4).The results of special calculations of efficiency should not be generalised even through they could be of valuable help in breeding, management techniques and making economic decisions in business under given conditions.     

不同绿色预混料对商品肉猪生产性能的影响

选择体重 15kg左右的杜×长×本三元杂交仔猪 12 0头 ,分为 3组 ,每组设 5个重复 ,每重复 8头猪进行试验 ,以观察不同绿色预混料对商品肉猪生产性能的影响。各组基础日粮完全相同 ,对照组饲喂含有药物添加剂的商品性预混料 ,2个试验组分别饲喂不含药物添加剂的自配预混料。试验结果表明 ,2个试验组的平均日增重明显高于对照组 (P <0 .0 5 ) ,而料重比和腹泻率明显低于对照组 (P <0 .0 5 ) ,肌肉pH值及肌内脂肪含量无明显差异 (P >0 .0 5 ) ,试验 2组与对照组相比 ,肌肉总色素含量明显提高 (P <0 .0 5 ) ,滴水损失明显下降 (P <0 .0 5 )。     

圈舍卫生状况及日粮色氨酸对断奶仔猪生产性能的影响

卫生状况的改变会影响动物色氨酸的代谢．可能会导致色氨酸供应不足。本试验旨在研究轻度炎症与色氨酸对动物生长性能、色氨酸代谢、血浆氨基酸浓度、血浆球蛋白、谷胱甘肽浓度等方面的影响。试验显示脏乱圈舍环境不仅可造成断奶仔猪轻度炎症反应．还会引起仔猪对色氨酸代谢的改变,表明充足的色氨酸有益于断奶仔猪生长．     

Effects of two different dietary fermentable carbohydrates on activity and heat production in group-housed growing pigs

The effects of two sources of dietary fiber (DF) on behavior and heat production (HP) in group-housed growing pigs were studied. Twenty clusters of 14 barrows (50 kg) were fed one of 10 diets. Diets differed mainly in type and content of fermentable DF (fDF) and in content of digestible starch. Five diets contained solvent-extracted coconut meal (SECM) and five diets contained soybean hulls (SBH) as the main fDF source. On an as-fed basis, pigs received 3.5, 13.2, 23.0, 32.7, or 42.4 g x kg(-0.75) x d(-1) of SECM or SBH. A total of 280 crossbred growing pigs were used, divided into clusters of 14 pigs each. Pigs were group-housed and fed at 2.5 times the assumed maintenance energy requirements. All clusters were fed similar amounts of NE, ileal-digestible protein and amino acids, vitamins, and minerals. Consequently, DMI differed among diets because NE content decreased with increasing DF content. After a 32-d preliminary period, HP was measured per cluster during a 7-d experimental period in environmentally controlled respiration chambers. Behavior of the pigs was recorded using time-lapse video recordings during two different days within the experimental period. Intake of digestible starch and fDF was different (P < 0.001) among diets, whereas intake of digestible CP was similar among diets. On average, pigs spent 153 min standing, 42 min sitting, 202 min lying on their chest, and 1,043 min lying on their flanks each day. Pigs fed SECM diets spent, on average, less time (P < 0.05) lying on their chest than pigs fed SBH diets. Total time spent on physical activity (i.e., standing plus sitting, 195 min/d) was not affected by diet. Total HP and resting HP were affected by diet and were on average lower (P < 0.01) for pigs fed SECM diets than for pigs fed SBH diets. Activity-related heat production (AHP) averaged 65 kJ x kg(-0.75) x d(-1) and was not affected by diet. There was a linear relationship (P < 0.001) between fDF intake and HP, but there was no relationship between fDF intake and AHP. During different parts of the day, fDF intake also affected HP. The saving effect of physical activity on the NE values of fDF from SECM and SBH were 0.56 and 0.84 kJ/g of fDF intake, respectively. Neither of these saving effects was significantly different from zero. We conclude that fDF from SECM and SBH did not affect energy expended on physical activity by growing pigs, and that the NE value of fDF from SECM and SBH was not affected by changes in physical activity.     

The impact of gastrointestinal parasites infection on slaughter efficiency in pigs

The aim of the present study was to determine an influence of parasites invasion on fodder consumption and slaughter yield of fatteners in three different maintenance systems. The experimental part of the study was conducted on pigs farm producing in a close cycle. The study on internal parasites of fatteners were conducted based on coproscopic methods. In order to describe the relationship between following variables: meatiness, slaughter yield, fodder consumption and mean EPG value, the principal component analysis (PCA) was used. The analysis between fodder consumption and maintenance system and fodder consumption and helminths infection did not demonstrate any significant relationship. The analysis between slaughter yield and meatiness and an infection demonstrated in turn a decrease in both parameters values in the two maintenance systems, i.e. in fatteners kept on litter meatiness decrease in infected fatteners of 4.2% and yield of 1.7%. On slatted floor meatiness decrease in infected fatteners of 6.1% and yield of 2.7%. The decreasing tendency in meat content (3.7%) and in slaughter yield (1.1%) was also observed in fatteners maintained on deep litter, however the values were not significant statistically.     

鱼油在猪饲料中的应用效果

1　妊娠期及哺乳期母猪种猪日粮添加鱼油试验的研究报道较多,研究目标主要集中在如何通过日粮途径,提高母源ｎ-3型脂肪酸的水平,从而提高胎儿生长发育、成活率、初生重及健康水平。目前的研究发现,妊娠期及哺乳期母猪日粮添加鱼油可以提高母猪及仔猪体内ｎ-3型脂肪酸的水平,并提高仔猪成活率及初生重。妊娠期和哺乳期母猪日粮添加35%～7%的鲱鱼油代替猪油能明显增加母猪血清、初乳和乳汁及新生仔猪体内ｎ-3型脂肪酸含量(Ａｎｔｈｏｎｙ等,1992;Ｆｒｉｔｓｃｈｅ等,1993),同时减少母猪免疫细胞中前列腺素Ｅ2(ＰＧＥ2)的产生,但不影响断奶仔猪…     

显微注射制备转基因小鼠的优化

显微注射法是目前应用最广泛的转基因小鼠制备技术,但其效率较低,提高显微注射法制备转基因小鼠的效率有重要意义。外源DNA浓度、小鼠品系均是影响转基因小鼠制备效率的因素,但目前较多文献采用KM小鼠进行转基因小鼠制备效率的优化,对C57/BL6小鼠研究较少。本实验以C57/BL6小鼠为对象,分别进行2.5 ng/μl、5.0 ng/μl的外源DNA浓度原核注射。结果显示,2.5 ng/μl组的怀孕率、出生率、小鼠阳性率、转基因效率均显著高于5.0 ng/μl组的结果(P0.05)。结论:通过原核注射方式获得C57/BL6转基因小鼠,注射的外源DNA浓度2.5 ng/μl效果较好。     

复合微生态制剂对猪生产性能的影响

随着经济和社会的发展,食品中的抗生素残留和菌株的耐药性问题已经越来越受大家关注.在这种情况下,开发低成本规模化生产的微微生态饲料添加剂已经成为一种科学养殖趋势.使用微生态制剂替代抗生素,一方面可以大大降低药源性(主要来自于饲料)疾病,改善猪群整体亚健康状况,另一方面也可以生产出无抗生素残留的优质猪肉产品,满足人们对绿色健康食品的迫切需求[1-2].本试验旨在应用复合微生态制剂,对生长育肥猪进行饲养试验,分别进行了复合微生态制剂替代药物添加剂试验、对肠道菌群的影响、对机体免疫水平的影响、对断奶仔猪发病率的影响及对生长育肥猪增重的影响等试验.     

Effects of milk yield on biological efficiency and profit of beef production from birth to slaughter

Effect of milk yield (MY) on biological efficiency and gross margin as an indicator of profit potential of beef production from birth to slaughter was determined. Data included 9 yr of spring-born single male calves. Biological efficiency was calculated as carcass weight/total feed energy intake, including nonlactating and lactating intakes of cow and creep and feedlot intakes of calf. Slaughter end point was finish constant at 9 mm of fat thickness. Gross margin was determined as returns minus feed costs. Three breeding systems were analyzed: purebred Hereford (HE), large rotational (LR), and small rotational (SR). Analyses were performed separately by breeding system when differences in the effect of MY among breeding systems were significant. Increased MY was associated with increased preweaning gain (P < .001), increased weight at start of feedlot trial (P < .001), and increased hot carcass weight (P < .05). No significant (P > .10) effect of MY on age at slaughter or on carcass weight per day of age at slaughter was found. Increased MY was associated with increased cow lactating energy intake (P < .10) and negatively associated with calf creep intake (P < .01). No effects of MY on intake of the cow during the nonlactating period, calf feedlot intake, or total feed intake were found. Increased MY was associated with a reduction in backfat thickness of the cow during the lactating period (P < .01) with no change in body weight. In the subsequent nonlactating period, increasing MY was associated with increased backfat thickness (P < .10) and body weight (P < .05). No effect of MY on change in backfat or weight of cow from calving to the end of the next nonlactating period was found. No effect of MY on biological efficiency to slaughter was detected. Milk yield was positively associated with gross margin from birth to slaughter (P < .05); results were similar when cow feed prices were reduced by 30%. Increased MY was associated with increased biological efficiency to weaning in HE (P < .01) and SR (P < .10), with no effect found in LR. When feeding cows to requirements, milk yield has a positive effect on the profit potential of beef production from birth to slaughter.     

2细胞期胚胎采集时间对电融合方法体外制备牛四倍体胚胎效率的影响

通过检测牛早期胚胎分裂速率的时间分布,并将体外受精后0~34 h与26~30 h时间段内采集的2细胞期胚胎分别作为电融合对照组与电融合试验组。将对照组与试验组的2细胞期胚胎分别用于电融合,并将电融合后的胚胎继续体外培养至囊胚期,检测并对比分析2组胚胎的融合率、分裂率、囊胚率和四倍体制备率。结果显示,牛2细胞期胚胎在体外受精后28~30 h其内分裂速率达到最高峰(18.9%)。电融合对照组的融合率、分裂率略高于试验组胚胎(85.2%vs.84.2%,82.2%vs.80.9%),试验组的囊胚率略高于电融合对照组(45.4%vs.44.8%),但差异均不显著。而电融合试验组的四倍体制备率显著高于电融合对照组(28.3%vs.14.5%)。结果表明,牛2细胞期胚胎的采集时间对电融合方法体外制备牛四倍体胚胎的效率有显著影响。     

不同水平的复方中草药添加对藏香猪生产性能及免疫功能的影响

为研究不同水平的复方中草药对藏香猪生长性能、免疫功能和抗氧化功能的影响,试验选择80头体重相近、30日龄左右健康藏香猪随机分为4组,即对照组,试验Ⅰ、Ⅱ、Ⅲ组,对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组在基础日粮中分别添加1%、2%、4%的复方中草药制剂,试验期30d。结果显示:与对照组相比,试验Ⅰ、Ⅱ组末重分别提高9.3%、13.6%(P<0.05);Ⅰ、Ⅱ、Ⅲ组甘油三脂、胆固醇和丙二醛含量均显著降低,血清中总抗氧化能力均显著提高,(P<0.05);Ⅲ组总蛋白显著提高7.9%(P<0.05),Ⅱ组IgG含量、谷胱甘肽分别提高21.5%、42.9%,Ⅱ、Ⅲ组IgA分别提高42.4%、28.2%(P<0.05),其余各指标之间差异不显著(P>0.05)。综上,不同水平的复方中草药添加均可提高藏香猪生长性能、免疫功能和抗氧化功能,且试验Ⅱ组添加剂量较Ⅰ、Ⅲ组效果好。