Influence of sex and castration of females on growth performance and carcass and meat quality of heavy pigs destined for the dry-cured industry

Crossbred pigs (n = 240) from Pietrain x Large White sires mated to Landrace x Large White dams, with an average age of 100 d (60.5 +/- 2.3 kg of BW), were used to investigate the effects of sex and slaughter weight (SW) on growth performance and on carcass and meat quality characteristics. There were 6 treatments arranged factorially, with 3 classes (intact females, IF; castrated females, CF; and castrated males, CM) and 2 slaughter weights (114 and 122 kg of BW). Each of the 6 combinations of treatments was replicated 4 times, and the experimental unit was a pen with 10 pigs. Castrated males and CF ate more feed, grew faster, and had more carcass backfat depth and fat thickness at the gluteus medius muscle but lower loin yield than IF (P < 0.05). In addition, CF and CM had more intramuscular fat (P < 0.05) and less linoleic acid content in the subcutaneous fat (P < 0.01) than IF. Pigs slaughtered at 122 kg of BW had lower ADG (P < 0.05), decreased G:F (P < 0.05), and more gluteus medius fat than pigs slaughtered at 114 kg of BW (P < 0.05). It was concluded that CF and CM had similar productive performance and meat quality characteristics when slaughtered at the same age, and that castration of females improved ADG and increased weight and fat content of primal cuts with respect to IF. Therefore, castration of females is recommended in pigs destined for the dry-cured industry because of the beneficial effects on quality of the primal cuts.     

Maternal grandsire,granddam, and sire breed effects on growth and carcass traits of crossbred cattle

Postweaning growth, feed efficiency, and carcass traits were analyzed on 1,422 animals obtained by mating F1 cows to F1 (Belgian Blue x British breeds) or Charolais sires. Cows were obtained from mating Hereford, Angus, and MARC IIIHereford, 1/4 Angus, 1/4 Pinzgauer, and 1/4 Red Poll) dams to Hereford or Angus (British breeds), Tuli, Boran, Brahman, or Belgian Blue sires. Breed groups were fed in replicated pens and slaughtered serially in each of 2 yr. Postweaning average daily gain; live weight; hot carcass weight; fat depth; longissimus area; estimated kidney, pelvic, and heart fat (percentage); percentage Choice; marbling score; USDA yield grade; retail product yield (percentage); retail product weight; fat yield (percentage); fat weight; bone yield (percentage); and bone weight were analyzed in this population. Quadratic regressions of pen mean weight on days fed and of cumulative ME consumption on days fed were used to estimate gain, ME consumption and efficiency (Mcal of ME/kg of gain) over time (0 to 200 d on feed), and weight (300 to 550 kg) intervals. Maternal grandsire breed was significant (P < 0.01) for all traits. Maternal granddam breed (Hereford, Angus, or MARC III)was significant (P < 0.05) only for fat depth, USDA yield grade, retail product yield, fat yield, fat weight, and bone yield. Sire breed was significant (P < 0.05) for live weight, hot carcass weight, longissimus area, and bone weight. Sex class was a significant (P < 0.001) source of variation for all traits except for percentage Choice, marbling score, retail product yield, and fat yield. Interactions between maternal grandsire and sire breed were nonexistent. Sire and grandsire breed effects can be optimized by selection and use of appropriate crossbreeding systems.     

不同杂交组合商品猪的肥育性能与胴体品质研究

本研究选用二元长大（L×Y）、三元杜长大（D×LY）、四元皮杜长大（PD×LY）三个杂交组合猪群为实验动物,进行生长发育性能、胴体品质性状测定,旨在为优质肉高效配套杂交组合筛选提供理论依据。研究表明：PD×LY日增重、料肉比及屠宰率最优,日增重、屠宰率与L×Y差异显著（P〈0．05）;PD×LY眼肌面积、后腿比例分别为48．09cm2、34．23％,为三组合中最高,并与L×Y差异显著（P〈0．05）,与D×LY组差异不显著（P〉0．05）。     

复合多糖对育肥猪生长性能和胴体品质的影响

试验旨在研究以牛膝、杜仲和玄参三种药用多糖进行配伍对生长育肥猪生长性能、屠宰性能和肉品质的影响,探讨复合多糖改善育肥猪生长性能及肉品质的机理。试验选用160头体重接近的生长育肥猪,采用单因素完全随机试验设计,分为5个处理:1)基础日粮组,2)抗生素组,3)0.05%复合多糖组,4)0.10%复合多糖组,5)0.15%复合多糖组。每组4个重复,每个重复8头猪,试验期共90 d。结果显示:1)与基础日粮组相比,0.10%复合多糖组和0.15%复合多糖组能显著提高猪日增重和降低料重比(P<0.05)。2)与基础日粮组相比,0.10%复合多糖组和抗生素组能显著提高猪屠宰率(P<0.05),复合多糖各组(0.05%,0.10%和0.15%)和抗生素组能显著降低猪的背膘厚并提高眼肌面积和瘦肉率(P<0.05)。3)与基础日粮组相比,复合多糖各组(0.05%,0.10%和0.15%)能显著提高猪背最长肌大理石纹评分并显著降低猪背最长肌的滴水损失(P<0.05)。与基础日粮组相比,抗生素组显著提高猪背最长肌的失水率和滴水损失(P<0.05)。结果表明复合多糖能够显著提高肌肉肉色评分、大理石纹评分、熟肉率,提高瘦肉率和肉品质。     

Effect of a potent analog of human growth hormone-releasing factor on carcass composition and quality of crossbred market pigs

The effect of a human growth hormone-releasing factor (hGRF) analog ([desamino-Tyr1, D-Ala2, Ala15] hGRF(1-29)NH2) on the carcass composition of crossbred barrows was evaluated. pH, color and collagen content were measured on 74 animals distributed among the following five treatments started at about 50 kg BW: T1, control saline three times daily (TID); T2, hGRF analog (1.66 micrograms/kg, TID); T3, hGRF analog (3.33 micrograms/kg, TID); T4, hGRF analog (6.66 micrograms/kg, TID) and T5, hGRF analog (10 micrograms/kg, once daily). Animals were slaughtered at approximately 106 kg BW giving an average of 55 d on test. Carcass composition was determined on eight animals from T1 and eight animals from T4. The left side of each carcass was divided into four untrimmed commercial cuts: ham, loin, shoulder and belly, which then were dissected into muscle, separable fat, bone and skin. Ham, loin and belly weights were not affected by GRF treatment, but shoulder weight was increased (P less than .05; 10.11 vs 11.15 kg, SE = .21). There was an increase (P less than .0.05) in muscle content of all the cuts considered and a concomitant decrease (P less than .05) in fat content. The analog increased muscle weight by 16% and decreased fat weight by 25% in the pooled tissues of the shoulder, ham and loin. Overall, hGRF analog increased skin and bone weights by 39% and 19%, respectively. Chemical analysis demonstrated that the hGRF analog increased overall protein accretion in the carcass by 10.5% and decreased crude fat by 28.7%.(ABSTRACT TRUNCATED AT 250 WORDS)     

胆囊收缩素主动免疫对猪生产性能、胴体品质及肉质的影响

为了研究胆囊收缩素(CCK-8)主动免疫对猪生产性能、胴体品质、肉质的影响,将12头体重为23.2±0.3kg的长荣猪随机分为2个处理,试验组和对照组,每个处理3个重复,每个重复2头猪,其中试验组猪注射CCK-8 人血清白蛋白(HSA),对照组猪则只注射HSA,测定猪的日采食量、日增重、料重比、屠宰率、胴体斜长、背膘厚、眼肌面积、pH、肉色评分、大理石纹、失水率、肌间脂肪等指标。试验期78d。整个试验期,与对照组相比,试验组的日增重低5.53%(P>0.05),日采食量高0.6%,料重比高6.64%(P>0.05),这表明,500μgCCK-8主动免疫有降低猪整个试验期生产性能的趋势,CCK-8免疫对猪胴体品质和肉质无显著影响,但对肉质有改善的趋势。     

烟台黑猪不同杂交组合猪肥育性能、胴体品质及肉质研究

研究测定了烟台黑猪与鲁育杜洛克、鲁育大约克和长白猪杂交商品猪的生长肥育性能、胴体品质及肉质。结果表明,大约克×烟黑组合日增重最高为717.37 g,料重比最低为2.97,与杜洛克×烟黑、长白×烟黑和烟黑×烟黑相比,日增重分别提高7.93%（P〉0.05）、16.22%（P〈0.05）和21.31%（P〈0.01）,料重比分别降低11.08%、3.88%、21.43%。4个组合的胴体性能及肉品质差异显著。其中,屠宰率以杜洛克×烟黑最高,比大约克×烟黑提高11.69%（P〈0.05）;眼肌面积也以杜洛克×烟黑最大,比烟黑×烟黑提高31.33%（P〈0.05）;瘦肉率以大约克×烟黑最高为60.24%,比烟黑×烟黑提高22.09%（P〈0.01）;大理石纹评分以烟黑×烟黑最高,其次是杜洛克×烟黑,分别比大约克×烟黑、长白×烟黑提高10.67%（P〉0.05）、38.02%（P〈0.05）和9.15%（P〉0.05）、36.12%（P〈0.05）;pH1以大约克×烟黑最高为6.66,其次是烟黑×烟黑组合为6.29,分别比杜洛克×烟黑、长白×烟黑提高14.63%（P〈0.01）、17.25%（P〈0.01）和8.26%（P〈0.01）、10.74%（P〈0.01）;失水率以杜洛克×烟黑最低,比长白×烟黑降低51.49%（P〈0.05）。4个组合的背最长肌氨基酸总量、鲜味氨基酸含量和必需氨基酸含量都以烟黑×烟黑组合最高,分别比大约克×烟黑和长白×烟黑提高10.07%（P〈0.01）和6.17%（P〈0.05）、9.55%（P〈0.01）和6.17%（P〈0.05）、11.18%（P〈0.01）和6.79%（P〈0.05）。背最长肌棕榈酸含量以杜洛克×烟黑最高,比大约克×烟黑提高10.59%（P〈0.05）;硬脂酸也以杜洛克×烟黑最高,分别比大约克×烟黑、长白×烟黑和烟黑×烟黑提高18.62%（P〈0.01）、20.5%（P〈0.01）和20.20%（P〈0.01）;油酸以烟黑×烟黑最高,比杜洛克×烟黑提高11.96%（P〈0.05）。     

甜菜碱和B族维生素对商品猪生长性能及同体肉品质影响

许多研究表明,甜菜碱可以促进肥育猪生长,改善饲料利用率,降低背膘厚,减少胴体脂肪沉积,增大眼肌面积和提高瘦肉率。日粮中添加B族维生素,可     

去势对公猪生长性能和胴体品质的影响

试验选用40头新生仔公猪,由5头健康母猪哺乳,每头母猪哺乳去势和完整仔公猪各4头。保育期开始分别饲养,记录全程的采食量和各阶段体重;分别于20、38、85、135和185日龄采集每头猪的粪便和血液样品,用于测定粪臭素和吲哚的含量;并分析血清中雄烯二酮、睾酮(T)、三碘甲腺原氨酸(T3)和生长激素(GH)水平;育肥末屠宰并分析胴体品质。结果显示,去势对猪的日增重无显著影响(P>0.05)。完整公猪平均背膘厚和肌内脂肪含量低于去势公猪(P<0.05);完整公猪脂肪中粪臭素和吲哚水平、血清中雄烯二酮水平高于去势公猪(P<0.05)。185日龄时,完整公猪血清中生长激素水平明显高于去势公猪(P<0.05)。各个日龄完整公猪血清中睾酮水平均极显著高于去势公猪(P<0.01)。结论:去势并不显著影响公猪的生长速率,但显著增加了背膘厚和肌内脂肪含量;完整公猪脂肪和血清中粪臭素和吲哚水平,血清中雄烯二酮水平均显著高于去势公猪。     

饲料中添加紫花苜蓿多糖对育肥猪生长性能和胴体品质的影响

为研究紫花苜蓿多糖对育肥猪生长性能及胴体品质的影响,选择体重相近的健康三元杂交育肥猪180头,随机分成3组,每个组3个重复,每个重复20头,1组饲喂基础日粮为对照组,2、3组分别在基础日粮中添加5.0%、10.0%紫花苜蓿多糖,预试验10 d,试验期60 d。在试验1 d和60 d测定生长性能指标,试验结束测定胴体品质。结果表明:(1)试验2、3组试验末重和平均日增重分别较对照组提高5.8%、6.2%、14.0%、14.9%(P <0.05),试验2、3组料重比分别较对照组降低4.6%、5.0%(P <0.05)。(2)试验2、3组屠宰率和瘦肉率分别较对照组提高4.2%、4.0%、5.8%、6.9%(P <0.05);试验2、3组胴体率均高于对照组(P> 0.05),试验2、3组背膘厚和眼肌面积分别较对照组降低7.8%、10.0%、8.9%、8.7%(P <0.05)。(3)试验2、3组肉质评价指标大理石评分、肉色、剪切力、p H24 h较对照组相比,均差异性不显著(P> 0.05)。综述所述,日粮中10.0%紫花苜蓿多糖可以提高育肥猪的生长性能和胴体品质。     

DDGS对生长育成猪的生产性能及胴体品质的影响

本试验旨在研究DDGS对生长育成猪的生产性能和胴体品质的影响。432头体重为29.8±0.2kg的育成猪被随机分成1-9个日粮组,分别为对照组（D0）,D15-0wk,D15-3wk,D15-6wk,D15-9wk,D30-0wk,D30-3wk,D30-6wk和D30-9wk,其中D0、D15和D30分别代表DDGS在猪日粮中的百分含量;0wk、3wk、6wk和9wk代表在屠宰0、3、6和9周前分别取消DDGS在猪日粮的添加时间。结果显示,当生长育成猪日粮中的DDGS含量为15%或30%时,不管屠宰前是否取消DDGS的添加,除了D30-0wk处理组的猪的ADG比对照组（D0）稍降外（0.87：0.92kg/d;P〈0.05）,其他处理组猪的ADG、ADFI和G：F均没有显著差异（P=0.76）。DDGS的不同含量或屠宰前取消DDGS的添加时间（0周、3周、6周和9周）对猪胴体质量、背最长肌（LM）猪肉品质、背脂和腹脂颜色评分分数没有显著影响（背脂,P=0.47;腹脂,P=0.17）。相对对照组,D30-0wk组的腹部猪肉嫩度稍低（P=0.04）,其他处理组猪的腹部猪肉嫩度与对照组的差别均不大（P=0.26）。当增加猪日粮中的DDGS含量时,腹脂的亚油酸含量（C18：2;P〈0.001）和碘值（IV;P〈0.001）有所增加。当猪日粮中含有15%DDGS时,在屠宰前的0～9周取消DDGS添加可以线性的降低猪腹脂的C18：2含量和腹脂碘值（屠宰前的第0-、3-、6-和9周的腹脂C18：2含量分别为：14.6%、13.3%、12.6%、10.9%;P=0.001;碘值分别为：67.3、64.4、64.1和62.7）;而当猪的日粮中含有30%DDGS时,在屠宰前0～9周取消DDGS的添加也可以线性的降低猪腹脂的C18：2含量和腹脂碘值（屠宰前的第0-、3-、6-和9周的腹脂C18：2含量分别为：17.3%、16.1%、14.2%和12.4%;P〈0.001;碘值分别为：71.2、68.2、64.5和62.7）。总体来看,当在生长育肥猪中添加高达30%DDGS对猪的生产性能有极小影响,且在屠宰前的3周取消在猪日粮中的DDGS的添加可以降低猪腹脂的C18：2含量和碘值。     

Effects of dietary iodine value product on growth performance and carcass fat quality of finishing pigs

A total of 120 barrows (initial BW = 47.9 ± 3.6 kg; PIC 1050) were used in an 83-d study to determine the effects of dietary iodine value (IV) product (IVP) on growth performance and fat quality. Pigs were blocked by BW and randomly allotted to 1 of 6 treatments with 2 pigs per pen and 10 pens per treatment. Dietary treatments were fed in 3 phases and formulated to 3 IVP concentrations (low, medium, and high) in each phase. Treatments were 1) corn-soybean meal control diet with no added fat (low IVP), 2) corn-extruded expelled soybean meal (EESM) diet with no added fat (medium IVP), 3) corn-soybean meal diet with 15% distillers dried grains with solubles and choice white grease (DDGS + CWG; medium IVP), 4) corn-soybean meal diet with low CWG (medium IVP), 5) corn-EESM diet with 15% DDGS (high IVP), and 6) corn-soybean meal diet with high CWG (high IVP). On d 83, pigs were slaughtered and backfat and jowl fat samples were collected and analyzed. The calculated and analyzed dietary IVP values were highly correlated (r(2) = 0.86, P < 0.01). Pigs fed the control diet, EESM, or high CWG had greater (P < 0.05) ADG than pigs fed EESM + DDGS. Pigs fed the control diet had greater (P < 0.05) ADFI than pigs fed all other diets. Pigs fed EESM + DDGS and high CWG had improved (P < 0.05) G:F compared with pigs fed the control diet or DDGS + CWG. Pigs fed diets with DDGS had greater (P < 0.05) backfat and jowl fat IV, C18:2n-6, and PUFA and less SFA than pigs fed all other treatments. Pigs fed EESM had greater (P < 0.05) backfat and jowl fat IV, C18:2n-6, and PUFA than pigs fed the control diet, low CWG, or high CWG. Pigs fed low CWG or high CWG had greater (P < 0.05) jowl fat IV than control pigs. Feeding ingredients high in unsaturated fatty acids, such as DDGS and EESM, had a greater impact on fat IV than CWG, even when diet IVP was similar. Therefore, IVP was a poor predictor of carcass fat IV in pigs fed diets with different fat sources and amounts of unsaturated fats formulated with similar IVP. Dietary C18:2n-6 content was a better predictor of carcass fat IV than diet IVP.     

Genetic parameters and purebred–crossbred genetic correlations for growth,meat quality,and carcass traits in pigs

Growth, meat quality, and carcass traits are of economic importance in swine breeding. Understanding their genetic basis in purebred (PB) and commercial crossbred (CB) pigs is necessary for a successful breeding program because, although the breeding goal is to improve CB performance, phenotype collection and selection are usually carried out in PB populations housed in biosecure nucleus herds. Thus, the selection is indirect, and the accuracy of selection depends on the genetic correlation between PB and CB performance (rpc). The objectives of this study were to 1) estimate genetic parameters for growth, meat quality, and carcass traits in a PB sire line and related commercial CB pigs and 2) estimate the corresponding genetic correlations between purebred and crossbred performance (rpc). Both objectives were investigated by using pedigree information only (PBLUP) and by combining pedigree and genomic information in a single-step genomic BLUP (ssGBLUP) procedure. Growth rate showed moderate estimates of heritability for both PB and CB based on PBLUP, while estimates were higher in CB based on ssGBLUP. Heritability estimates for meat quality traits were diverse and slightly different based on PB and CB data with both methods. Carcass traits had higher heritability estimates based on PB compared with CB data based on PBLUP and slightly higher estimates for CB data based on ssGBLUP. A wide range of estimates of genetic correlations were obtained among traits within the PB and CB data. In the PB population, estimates of heritabilities and genetic correlations were similar based on PBLUP and ssGBLUP for all traits, while based on the CB data, ssGBLUP resulted in different estimates of genetic parameters with lower SEs. With some exceptions, estimates of rpc were moderate to high. The SE on the rpc estimates was generally large when based on PBLUP due to limited sample size, especially for CBs. In contrast, estimates of rpc based on ssGBLUP were not only more precise but also more consistent among pairs of traits, considering their genetic correlations within the PB and CB data. The wide range of estimates of rpc (less than 0.70 for 7 out of 13 traits) indicates that the use of CB phenotypes recorded on commercial farms, along with genomic information, for selection in the PB population has potential to increase the genetic progress of CB performance.     

Effects of choice white grease and soybean oil on growth performance, carcass characteristics, and carcass fat quality of growing-finishing pigs

A total of 144 barrows and gilts (initial BW = 44 kg) were used in an 82-d experiment to evaluate the effects of dietary fat source and duration of feeding fat on growth performance, carcass characteristics, and carcass fat quality. Dietary treatments were a corn-soybean meal control diet with no added fat and a 2 × 4 factorial arrangement of treatments with 5% choice white grease (CWG) or soybean oil (SBO) fed from d 0 to 26, 54, 68, or 82. At the conclusion of the study (d 82), pigs were slaughtered, carcass characteristics were measured, and backfat and jowl fat samples were collected. Fatty acid analysis was performed, and iodine value (IV) was calculated for all backfat and jowl fat samples. Pigs fed SBO tended to have increased (P = 0.07) ADG compared with pigs fed CWG. For pigs fed SBO, increasing feeding duration increased (quadratic, P < 0.01) ADG and G:F. For pigs fed CWG, increasing feeding duration improved (quadratic, P < 0.01) G:F. For pigs fed SBO or CWG, increasing feeding duration increased carcass yield (quadratic, P < 0.04) and HCW (quadratic, P < 0.02). Dietary fat source and feeding duration did not affect backfat depth, loin depth, or lean percentage. As expected, barrows had greater ADG and ADFI (P < 0.01) and poorer G:F (P = 0.03) than gilts. Barrows also had greater last-rib (P = 0.04) and 10th-rib backfat (P < 0.01) and reduced loin depth and lean percentage (P < 0.01) compared with gilts. Increasing feeding duration of CWG or SBO increased (P < 0.10) C18:2n-6, PUFA, PUFA:SFA ratio, and IV in jowl fat and backfat. Pigs fed SBO had greater (P < 0.01) C18:2n-6, PUFA, PUFA:SFA ratio, and IV but decreased (P < 0.01) C18:1 cis-9, C16:0, SFA, and MUFA concentrations compared with pigs fed CWG in jowl fat and backfat. Barrows had decreased (P = 0.03) IV in jowl fat and backfat compared with gilts. In summary, adding SBO or CWG increased the amount of unsaturated fat deposited. Increasing feeding duration of dietary fat increases the amount of unsaturated fatty acids, which leads to softer carcass fat.     

非淀粉多糖酶对生长育肥猪生长性能、胴体性状和肉品质的影响

本研究主要通过生长育肥猪的饲养试验,观察日粮中添加非淀粉多糖酶(Non-Starch Polysaccharide Enzyme,NSP酶)对生长育肥猪生长性能、胴体性状和肉品质的影响。试验选择体质量约为40kg的杜长大三元杂交猪48头,公母各半。本试验随机分为2个处理,每个处理3个重复,每个重复8头猪,对照组饲喂基础日粮,NSP酶组饲喂基础日粮+0.6%NSP酶。结果表明:(1)生长性能方面,NSP酶组的平均日增重和平均日采食量均显著高于对照组(P<0.05),分别提高了9.8%和4.7%;NSP酶组的料重比显著低于对照组(P<0.05),降低了5.0%;(2)在胴体性状和背最长肌化学组成方面,NSP酶组眼肌面积比对照组显著提高(P<0.05),提高了9.8%;与对照组相比,滴水损失和剪切力2个指标分别降低了2.0%和14.6%,但在统计学上未达到显著水平(P>0.05)。结果显示,基础饲粮中添加NSP酶能有效提高生长育肥猪生长性能,并在一定程度上改善肉品质。     

超微茶粉对生长猪生长性能、胴体品质及脂肪代谢的影响

为了研究超微茶粉对生长猪生长性能、胴体品质及脂肪代谢的影响,将64头50 kg左右的杜长大阉公猪随机分为4组,每组4栏(重复),每栏4头,对照组采食基础日粮,试验组分别添加0.5%、1.0%和1.5%的超微茶粉,试验期70 d,试验结束时计算日增重、料重比,然后屠宰测定分析肌肉胴体品质及脂肪沉积性能。结果表明,超微茶粉对生长猪生长性能没显著影响,并且能显著降低肌内脂肪(IMF)含量,可以显著提高生长猪的瘦肉率和眼肌面积、猪肉肉色以及降低滴水损失和剪切力(P<0.05)。同时,利用前体脂肪细胞研究表没食子儿茶素没食子酸酯(EGCG)对脂肪代谢关键基因表达的影响,结果表明,前体脂肪细胞在EGCG作用下,p-AMPKα蛋白和LPL基因表达显著增加,同时C/EBPβ、SREBP-1、PPARγ基因表达显著降低(P<0.05)。我们的结果提示,超微茶粉对生长猪生长性能没有影响,但可以显著改善肌肉品质,其作用机理可能与对脂肪代谢的调控有关。     

Effect of carbohydrate source on growth performance, carcass traits, and meat quality of growing-finishing pigs

Two experiments were conducted to determine the effect of substituting a more available dietary carbohydrate (CHO) for portions of corn or fat in the diet on growth performance, carcass traits, meat quality, and serum or plasma metabolites in growing-finishing pigs. A three-phase feeding program was used with corn-soybean meal diets formulated to provide 105% of the Lys requirement for barrows or gilts gaining 325 g of lean daily in Exp. 1 or gilts gaining 350 g of lean daily in Exp. 2. Diets were isoenergetic within experiments. All other nutrients met or exceeded suggested requirements. In Exp. 1, pigs were allotted to three dietary treatments (0, 7.5, or 15.0% sucrose), with three replications of barrows and three replications of gilts, and with three or four pigs per replicate pen; average initial and final BW were 25.2 and 106.7 kg. In Exp. 2, gilts were allotted to two dietary treatments (waxy [high amylopectin] or nonwaxy [75% amylopectin and 25% amylose] corn as the grain source), with five replications of four gilts per replicate pen; average initial and final BW were 37.7 and 100.0 kg. In Exp. 1, ADG and gain:feed ratio increased linearly (P < 0.02) as dietary sucrose increased. Minolta color scores, a* and b*, and drip loss (P < 0.06) also increased linearly with added sucrose. In Exp. 2, ADG, carcass weight and length, and the Minolta a* value were greater for pigs fed waxy corn (P < 0.08) than for those fed nonwaxy corn. Feed intake, longissimus muscle area, 10th-rib and average backfat thickness, dressing percentage, fat-free lean, percentage of lean and muscling, lean gain per day, total fat, percentage fat, lean:fat ratio, serum or plasma metabolites (Exp. 1: serum urea N; Exp. 2: serum urea N, and plasma nonesterified fatty acids, triacylglycerols, total and high-density lipoprotein cholesterol, insulin, and total protein), pH of the longissimus muscle, and subjective muscle scores (color, firmness-wetness, and marbling) were not affected by diet in either experiment. In summary, increasing availability of dietary CHO in growing-finishing pig diets improved growth performance, but it did not affect carcass traits.     

小肽复合剂对育肥猪的生长性能及胴体和肉质性状的影响效应研究

试验旨在研究小肽复合剂对育肥猪生长性能、胴体性状及肉质性状的影响效果。将72头同批次健康的65日龄的(长×大)二元杂交商品猪随机分为试验组和对照组,每组设3个重复,每重复12头猪。试验组在正常饲粮中添加0.2%的小肽复合剂,对照组为正常饲粮。试验结果发现:育肥阶段饲喂0.2%的小肽复合剂能够显著提高育肥猪生长性能和改善肉质性状。表现为提高育肥猪的日增重(P<0.05),增加育肥猪的采食量,提高饲料转化效率,提高育肥猪群的成活率,降低生病率和腹泻率。肉质性状方面,显著降低滴水损失(P<0.05),增加了肌肉的保水力,生长性能和肉质性状的改善显著地提高了育肥猪的综合经济效益。     

合生素对白羽肉鸡生产性能及胴体品质的影响

1材料与方法1．1试验动物与设计试验选用内蒙古草原兴发股份有限公司培育的1日龄健康白羽肉鸡雏480羽,公母各半,按体质量随机分成4个处理组。处理A为正对照组（使用抗生素）;处理B为负对照组（不使用抗生素）;处理D为0．10％合生素组;处理E为0．05％合生素组。