斜发沸石对苏淮育肥猪血液生化指标和肠道形态的影响

旨在研究基础日粮中添加不同水平的斜发沸石对苏淮育肥猪血液生化指标、肠道形态的影响,为斜发沸石在苏淮猪生产中的应用提供数据参考。选择体重(50±2)kg、健康的苏淮阉公猪40头,随机分为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组共4个处理组。试验预饲期10 d,所有猪自由采食对照组基础日粮;正试期64 d,对照组饲喂基础日粮,试验Ⅰ至Ⅲ组分别在基础日粮中添加0.5%、1.0%、2.0%的斜发沸石。结果:随斜发沸石水平增加,血清免疫球蛋白G(IgG)、肠道黏膜分泌型免疫球蛋白(sIgA)和肠道黏膜IgG含量升高。随斜发沸石水平增加,血清碱性磷酸酶含量升高;血清甘油三酯含量先升高后降低。随斜发沸石水平增加,平均红细胞血红蛋白浓度含量升高;红细胞分布宽度变异系数降低。随斜发沸石水平增加,十二指肠隐窝深度降低;空肠绒毛高度和空肠段绒毛高度/隐窝深度有升高的趋势。试验表明,在各组日粮消化能和粗蛋白均满足且一致的情况下,添加适宜比例斜发沸石对改善猪的机体血液及肠道免疫功能有积极作用。综合考虑以上检测指标变化规律及斜发沸石添加成本,建议斜发沸石的适宜添加比例为1.0%。     

不同脱脂米糠水平日粮对苏淮猪胴体性状及肉品质的影响

旨在研究不同脱脂米糠水平日粮对苏淮猪胴体性状及肉品质的影响。选取35头初始体重为(62.9±0.8) kg的健康纯种苏淮阉公猪,随机分为5组,每组7个重复,每个重复1头猪,使用奥斯本种猪生产性能测定系统(OTSS)饲喂。对照组(CTRL)饲喂不含脱脂米糠的基础日粮,试验Ⅰ～Ⅳ组分别饲喂7%、14%、21%和28%脱脂米糠的试验日粮,5组日粮的中性洗涤纤维(NDF)水平分别为8.89%、11.80%、12.93%、14.35%和17.94%,各组日粮除纤维水平不同外,其他营养成分基本一致。试验预饲期10 d,所有猪饲喂基础日粮;正式期28 d,分别饲喂基础日粮和试验日粮。试验结束屠宰全部试验猪,测定其胴体性状(胴体重、屠宰率、胴体直长、胴体斜长、眼肌面积、平均背膘厚和皮厚);采集肉样用于测定肉质性状(滴水损失、剪切力、熟肉率、肌内脂肪含量、pH和肉色);采集背最长肌样品用于猪滴水损失主效基因磷酸化酶激酶γ1(phosphorylase kinase gamma1,PHKG1)表达分析。结果表明:1)日粮脱脂米糠水平对苏淮猪的胴体重、屠宰率、胴体直长、胴体斜长、眼肌面积、平均背膘厚和皮厚等胴体指标没有显著影响。2)随脱脂米糠水平的提高,苏淮猪背最长肌的滴水损失呈先降低后上升的二次曲线变化(P0.05),猪肉的剪切力线性降低(P0.05);熟肉率、pH_(24 h)随脱脂米糠水平的增加呈线性增加的趋势(P=0.061,P=0.068);日粮脱脂米糠水平的增加有降低L~*_(24 h)的趋势(线性,P=0.085),脱脂米糠水平对其它肉质指标均无显著影响。3)PHKG1基因的相对表达量随脱脂米糠水平的增加趋于二次方升高(P=0.085)。综上所述,日粮脱脂米糠水平对苏淮育肥猪的胴体性状无显著影响,但在日粮中适度添加脱脂米糠可降低苏淮猪猪肉的滴水损失及剪切力,改善苏淮猪猪肉品质,但其背后的机制还有待进一步深入研究。     

不同脱脂米糠水平日粮对苏淮猪胴体性状及肉品质的影响

旨在研究不同脱脂米糠水平日粮对苏淮猪胴体性状及肉品质的影响。选取35头初始体重为（62.9±0.8）kg的健康纯种苏淮阉公猪,随机分为5组,每组7个重复,每个重复1头猪,使用奥斯本种猪生产性能测定系统（OTSS）饲喂。对照组（CTRL）饲喂不含脱脂米糠的基础日粮,试验Ⅰ~Ⅳ组分别饲喂7%、14%、21%和28%脱脂米糠的试验日粮,5组日粮的中性洗涤纤维（NDF）水平分别为8.89%、11.80%、12.93%、14.35%和17.94%,各组日粮除纤维水平不同外,其他营养成分基本一致。试验预饲期10 d,所有猪饲喂基础日粮;正式期28 d,分别饲喂基础日粮和试验日粮。试验结束屠宰全部试验猪,测定其胴体性状（胴体重、屠宰率、胴体直长、胴体斜长、眼肌面积、平均背膘厚和皮厚）;采集肉样用于测定肉质性状（滴水损失、剪切力、熟肉率、肌内脂肪含量、pH和肉色）;采集背最长肌样品用于猪滴水损失主效基因磷酸化酶激酶γ1（phosphorylase kinase gamma1,PHKG1）表达分析。结果表明：1）日粮脱脂米糠水平对苏淮猪的胴体重、屠宰率、胴体直长、胴体斜长、眼肌面积、平均背膘厚和皮厚等胴体指标没有显著影响。2）随脱脂米糠水平的提高,苏淮猪背最长肌的滴水损失呈先降低后上升的二次曲线变化（P<0.05）,猪肉的剪切力线性降低（P<0.05）;熟肉率、pH_{24 h}随脱脂米糠水平的增加呈线性增加的趋势（P=0.061,P=0.068）;日粮脱脂米糠水平的增加有降低L_{24 h}^*的趋势（线性,P=0.085）,脱脂米糠水平对其它肉质指标均无显著影响。3）PHKG1基因的相对表达量随脱脂米糠水平的增加趋于二次方升高（P=0.085）。综上所述,日粮脱脂米糠水平对苏淮育肥猪的胴体性状无显著影响,但在日粮中适度添加脱脂米糠可降低苏淮猪猪肉的滴水损失及剪切力,改善苏淮猪猪肉品质,但其背后的机制还有待进一步深入研究。     

胍基乙酸对育肥猪生长性能、胴体品质及肉品质的影响

本试验旨在研究日粮添加胍基乙酸对育肥猪的生长性能、胴体品质及肉品质的影响。试验选用72头初始体重(75.10±0.75)kg的健康三元杂交(杜×长×大)育肥猪,按体重一致、公母各半的原则,随机分为2个处理,每个处理6个重复,每个重复6头猪,试验期45 d。对照组饲喂基础日粮,试验组在基础日粮中添加500 mg/kg胍基乙酸。结果表明:日粮添加胍基乙酸显著提高了育肥猪平均日增重(P0.05),显著降低其耗料增重比(P0.05),对平均日采食量无显著影响(P0.05);日粮添加胍基乙酸提高了育肥猪胴体重、屠宰率和标准无脂瘦肉率(P0.05),显著降低其第10肋背膘厚度(P0.05),但对其眼肌面积无显著影响(P0.05);日粮添加胍基乙酸提高了育肥猪背最长肌肉红度(a*)、pH_(45 min)和pH_(24 h),显著降低了其滴水损失(P0.05)。综上所述,日粮添加500μg/kg胍基乙酸改善了育肥猪生长性能、胴体品质和肉品质。     

肉碱与甜菜碱对育肥猪胴体、肉品质及肝脏营养成分的影响

本试验采用两因素3×3析因设计,研究了日粮中添加3个内碱水平(0、50、100 mg/kg)和3个甜菜碱水平(0、1000、1500 mg/kg)对杜长大三元杂交育肥猪胴体品质、肉品质和肝脏营养成分的影响.选择90头体重约为100kg的杜长大三元杂交肥育猪,按体重相近、性别比例相同原则,随机分为9处理组,每组10头.其中第1组为对照组,喂基础日粮;第2～9组为试验组,喂试验日粮.试验期为30 d.结果表明:肉碱添加水平对育肥猪背膘厚、眼肌面积、大理石纹和肝脏蛋白质含量影响显著(P＜0.05).甜菜碱添加水平对育肥猪背膘厚、肉色评分和肝脏粗脂肪含量影响显著(P＜0.05),并证实了肉碱与甜菜碱时育肥猪的胴体组成、肉质和肝脏营养成分的影响不存在交互效应.     

低蛋白日粮对育肥猪胴体品质的影响

为进一步研究低蛋白日粮对育肥猪胴体品质的影响,试验选择初始体重为50kg左右的杜×大×长三元健康猪300头,采用单因子设计,分为高蛋白组和低蛋白组。高蛋白组中日粮按照NRC(1998)营养需要量推荐配制,低蛋白组在NRC推荐的日粮粗蛋白水平上降低4个百分点。试验结果表明,在胴体品质方面,低蛋白组和高蛋白组的眼肌面积分别为49.415cm2、46.279cm2,差异不显著(P=0.937),第十肋被膘厚度低蛋白组和高蛋白组分别为2.175cm、2.215cm,差异不显著(P=0.929),瘦肉率则有增加的趋势(P=0.552)。综合上述结果,商业化生产条件下,育肥猪饲喂低蛋白日粮对猪的胴体品质没有影响。     

饲粮纤维源对育肥猪生长性能、胴体组成和肉品质的影响

本文旨在探讨不同纤维源对育肥猪生长性能、胴体组成和肉品质的影响.试验选用125头初始体重为(48.88±0.81) kg健康“杜×长×大”三元杂交生长肥育猪,随机分为5组,每组5个重复,每个重复5头猪,分别饲喂基础饲粮(对照组)以及添加玉米纤维、大豆纤维、小麦麸纤维和豌豆纤维的4种试验饲粮,饲粮纤维的添加量为30％.试验猪体重约为100kg时结束试验.结果表明:1)与对照组相比,大豆纤维组猪的末重和平均日增重显著降低(P＜0.05),大豆纤维组、小麦麸纤维组和豌豆纤维组猪的平均日采食量极显著降低(P＜0.01),小麦麸纤维组和豌豆纤维组猪的料重比显著降低(P＜0.05).2)饲粮中添加4种纤维有降低猪屠宰率的趋势(P=0.06),但对猪的胴体斜长和眼肌面积无显著影响(P＞0.05);而大豆纤维组、小麦麸纤维组和豌豆纤维组猪的平均背膘厚显著低于对照组(P＜0.05).3)饲粮中添加4种纤维有增加猪背最长肌中粗蛋白质含量的趋势(P=0.07),但对背最长肌PH45min亮度值、大理石纹评分和剪切力均无显著影响(P＞0.05);与对照组相比,豌豆纤维组猪的背最长肌pH24h显著提高(P＜0.05),背最长肌滴水损失显著降低(P＜0.05);而大豆纤维组和小麦麸纤维组猪背最长肌肌内脂肪含量显著降低(P＜0.05).本研究提示,饲粮中不同的纤维来源会对育肥猪的生长性能、胴体组成和肉品质产生不同程度的影响,其中,豌豆纤维对保障育肥猪的生长性能、改善肉品质的效果较好.     

断奶仔猪日粮添加不同水平乳制品对断奶-育肥猪生长性能、腹泻率和肉品质的影响

本研究以断奶仔猪为研究对象,对断奶期-育肥期猪的生长性能、血液生化指标、胴体特征进行评价。试验采用完全随机试验设计,将320头断奶仔猪[平均体重为(7.01±1.32)kg]按体重和性别分为4组,每组8个重复,每个重复10头。断奶期日粮分别添加0、10%、20%和30%乳制品(乳清粉和乳糖,1～2 w)以及0、5%、10%和15%乳制品(乳清粉和乳糖,3～5 w)。断奶期间(1～5 w)仔猪饲喂试验饲料,所有仔猪在生长期(6～19 w)饲喂相同的商品饲料。结果 :仔猪体重、日增重和日采食量随日粮乳制品添加水平的升高显著线性增加(P 0.05)。其中体重在5和13 w线性升高(P 0.05),日采食量在5～9 w表现为显著线性升高(P 0.05),而饲料效率在14～17 w表现为显著二次曲线效应(P 0.05)。各处理组间血清尿素氮浓度无显著性差异(P 0.05)。随着断奶仔猪日粮乳制品添加水平的升高,最长肌粗蛋白质表现为二次曲线效应(P 0.05),粗灰分含量呈线性降低(P 0.05),蒸煮损失呈线性增加(P 0.05),系水力呈线性降低(P 0.05)。结论 :断奶仔猪日粮中添加5%～10%的乳制品对生长育肥期的效果与日粮中添加0或15%～30%乳制品的效果相当,对育肥猪生长性能无负面影响。     

日粮脱脂米糠替代玉米水平对苏淮猪生长性能、肠道发育及养分消化率的影响

旨在研究日粮脱脂米糠替代玉米水平对苏淮育肥猪生长性能、肠道发育及养分表观消化率的影响,筛选苏淮猪最适宜的脱脂米糠替代玉米水平。本试验选择体重相近(62.90±0.78)kg、健康的苏淮阉公猪35头,随机分为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组、试验Ⅳ组5个处理组。每组7个重复,每个重复1头猪。试验预饲期10 d,所有猪自由采食对照组基础日粮;正试期28 d,对照组饲喂基础日粮,试验Ⅰ～Ⅳ组分别饲喂以7%、14%、21%、28%的脱脂米糠替代等量玉米的日粮。5组日粮的中性洗涤纤维(NDF)水平分别为8.89%、11.80%、12.93%、14.35%、17.94%。正式期所有猪均自由采食和饮水。试验期每天纪录所有试验猪的采食量和体重;分别于试验期第0、14天采集粪样,试验第28天采集直肠内容物,用于测定养分表观消化率;试验结束屠宰全部试验猪,测量计算胃肠道相对质量和相对长度。结果表明:1)各处理组间猪的初始体重、第14天体重、终末体重、平均日采食量(ADFI)、平均日增重(ADG)、第0～14天平均日增重、第14～28天平均日增重、料重比(F/G)均无显著差异(P>0.05)。但对照组、试验Ⅰ～Ⅳ组的第14～28天平均日增重显著高于第0～14天平均日增重(P<0.05)。生长拟合曲线显示,各组猪生长曲线拐点分别是第18.51天(75.87 kg)、第15.92天(73.61 kg)、第17.39天(75.91 kg)、第17.58天(75.45 kg)、第16.29天(76.15 kg)。与对照组相比,试验组猪较早到达生长曲线拐点。但各组生长趋势差异不明显。2)饲喂不同纤维水平的日粮对各组猪胃肠道相对重量、长度及大肠的重量、长度占比均无显著影响(P>0.05)。3)试验期第14、28天,随着日粮纤维水平的升高,各组NDF表观消化率与对照组无显著差异(P>0.05),酸性洗涤纤维(ADF)和粗蛋白(CP)表观消化率均呈线性(P<0.01)、二次方(P<0.01)和三次方(P<0.01)降低;试验期第14天,粗脂肪(EE)表观消化率趋于二次方降低(P<0.10)。4)根据三次方程模型预测,分别以ADF、CP表观消化率为因变量,得到适宜脱脂米糠替代部分玉米水平分别为12.77%、14.78%。在各组日粮消化能和粗蛋白均满足且一致的情况下,增加日粮纤维水平对苏淮育肥猪生长性能、肠道发育、NDF表观消化率没有显著影响,但降低了对ADF和CP的表观消化率。本试验的脱脂米糠替代部分玉米是可行的,替代比例以12.77%最佳。     

添加铁对育肥猪生产性能、胴体特性和零售展示期间猪肉品质的影响

为了检验日粮中添加铁对生长育肥猪生产性能和胴体特性的影响,把185头杂种猪按照体重随机分组,5圈舍/组,5~6头/圈舍。对照组(NC)饲喂玉米-豆粕生长育肥日粮,预混料中无铁;试验组(PC)饲喂玉米-豆粕生长育肥日粮,预混料中含铁。PC日粮分别添加50、100或150 mg/kg可利用铁(一种氨基酸铁复合物)。当最轻的组平均体重为118.2 kg时屠宰,分割过程中带骨的背腰肉用于猪肉品质的测定数据。生长第1阶段,添加铁降低日增重(ADG)(P=0.10),然而生长第2阶段添加铁提高日增重(ADG)。尽管饲喂NC猪在肥育第1阶段增重:耗料比(G∶F)较大(P<0.05),在整个试验(P=0.07),活体性能日粮处理无差异(P>0.13)。线性增加10肋的背膘厚(P=0.08)和计算出的无脂肪瘦肉产量(P=0.06);另外,日粮铁对猪肉胴体肌肉和脂肪无影响(P>0.19)。而且,不同铁处理之间LM总浓度、血红素、非血红素铁相近(P>0.23)。每个处理随机选取腰肉进一步做成2.5 cm厚的LM猪排,放在聚苯乙烯泡沫塑料盘中,覆盖聚氯乙烯薄膜后,放在陈列柜中陈列(2.6℃),持续荧光照射7 d(1600 lx)。在陈列过程中,对照组和日粮中添加100 mg/kg铁的猪排肉色更加鲜明(较高的色度值;P=0.07),比日粮中添加50 mg/kg铁的LM猪排肉色更加红(较高的色度值;P=0.09)。而且,日粮中添加100 mg/kg铁的猪肉红色:黄色比率较大(P<0.01),显示比来自添加PC或猪日粮中添加50 mg/kg铁的猪肉更红。总之,无论如何,提高日粮中铁含量,对生产性能、胴体或LM特性无显著影响,说明目前日粮铁推荐含量对于猪的最佳生长性能、胴体成分和猪肉品质是足够的。     

Effects of zeolite a or clinoptilolite in diets of growing swine

Growth, nutrient balance, plasma ammonia levels and urinary p-cresol excretion were evaluated in growing pigs fed diets containing various levels of zeolite A or clinoptilolite. In one growth trial, crossbred pigs averaging 25 kg initial body weight were assigned to diets containing no zeolite, .3% zeolite A or .5% clinoptilolite for a 6-wk growing phase trial. Average daily gain (ADG), average daily feed intake (ADF) and feed/gain (F/G) were unaffected by supplementation of either zeolite in the diet, but metabolizable energy (ME) utilization was improved by feeding diets containing either zeolite. A second growth trial utilized the same crossbred pigs, which averaged 65 kg initial body weight, and were assigned to diets containing no zeolite, 1% zeolite A or 5% clinoptilolite for an 8-wk finishing phase trial. Average daily gain, ADF, and ME utilization were unaffected by feeding either zeolite diet, while F/G was increased in pigs fed the diet containing 5% clinoptilolite. In two nutrient balance trials, 16 crossbred pigs averaging 7.5 kg in initial body weight were fed diets containing 0, 1, 2 or 3% zeolite A in one trial and 16 crossbred pigs averaging 7.0 kg initial body weight were fed diets containing 0, 2.5, 5.0 or 7.5% clinoptilolite in a second trial. In both trials, digestible energy, ME, N-corrected ME and ME corrected for N balance and zeolite levels were linearly reduced as increasing amounts of either zeolite were fed. Daily fecal N increased and apparent digestibility of N was linearly reduced by feeding increasing amounts of zeolite A or clinoptilolite. Biological value of protein was improved linearly as higher levels of zeolite A were fed, indicating that there may be some ammonia binding to zeolite A in the gastrointestinal tract. Net protein utilization was reduced by feeding increasing levels of clinoptilolite in the diet. Calcium, P, Mg, Na, K and Fe retentions were linearly reduced by feeding increasing amounts of zeolite A in the diet, while increasing levels of clinoptilolite caused only P retention to be linearly reduced. Both free and conjugated forms of urinary p-cresol were linearly reduced by feeding increasing levels of clinoptilolite. Plasma ammonia levels were reduced at subsequent bleedings after a meal and by increasing levels of clinoptilolite.     

Influence of level of dietary protein or energy on effects of ractopamine in finishing swine.

The effect of ractopamine, a beta-adrenergic agonist, on growth, nutrient utilization, and carcass composition was studied in pigs fed either 18% CP, 12% CP, or 18% CP restricted (RES = 67% of ad libitum) diets. The 18 and 12% CP diets provided 3.52 and 3.68 Mcal of DE/kg, respectively. All pigs were fed a low-protein (12% CP) diet during pretreatment growth from 15 to 60 kg. Ractopamine at 20 or 30 ppm (30 ppm for RES pigs) in the diet was fed from 60 kg live BW until slaughter at 105 kg (9 pigs/treatment). No ractopamine treatment effect (P greater than .05) was observed for either daily gain or gain/feed, although gain/feed was improved by 8% in both of the ad libitum groups. Ractopamine treatment resulted (P less than .01) in an overall reduction of carcass lipid by 8%, an increase of carcass protein by 5%, and a 21% improvement in the efficiency of protein utilization; the greatest changes occurred in the pigs fed the 12% CP diet (-17%, +11%, and +32%, respectively). The ad libitum daily feed intake was 15% less for pigs fed the 12% CP diet than for those fed the 18% CP diet (P less than .01), and there was a 10% reduction in intake of both diets with the addition of ractopamine (P less than .05). Both carcass lipid and protein deposition seemed to be closely related to energy intake (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of dietary betaine on nutrient utilization and partitioning in the young growing feed-restricted pig

The purpose of this study was to examine the effects of dietary betaine over a range of concentrations (between 0 and 0.5%) on growth and body composition in young feed-restricted pigs. Betaine is associated with decreased lipid deposition and altered protein utilization in finishing pigs, and it has been suggested that the positive effects of betaine on growth and carcass composition may be greater in energy-restricted pigs. Thirty-two barrows (36 kg, n = 8 pigs per group) were restrictively fed one of four corn-soybean meal-skim milk based diets (18.6% crude protein, 3.23 Mcal ME/kg) and supplemented with 0, 0.125, 0.25, or 0.5% betaine. Feed allotment was adjusted weekly according to BW, such that average feed intake was approximately 1.7 kg for all groups. At 64 kg, pigs were slaughtered and visceral tissue was removed and weighed. Carcasses were chilled for 24 h to obtain carcass measurements. Subsequently, one-half of each carcass and whole visceral tissue were ground for chemical analysis. Linear regression analysis indicated that, as betaine content of the diet was elevated from 0 to 0.5%, carcass fat concentration (P = 0.06), P3 fat depth (P = 0.14) and viscera weight (P = 0.129) were decreased, whereas total carcass protein (P = 0.124), protein deposition rate (P = 0.98), and lean gain efficiency (P = 0.115) were increased. The greatest differences over control pigs were observed in pigs consuming 0.5% betaine, where carcass fat concentration and P3 fat depth were decreased by 10 and 26%, respectively. Other fat depth measurements were not different (P > 0.15) from those of control pigs. In addition, pigs consuming the highest betaine level had a 19% increase in the carcass protein:fat ratio, 23% higher carcass protein deposition rate, and a 24% increase in lean gain efficiency compared with controls. Dietary betaine had no effects (P > 0.15) on growth performance, visceral tissue chemical composition, carcass fat deposition rate, visceral fat and protein deposition rates, or serum urea and ammonia concentrations. These data suggest that betaine alters nutrient partitioning such that carcass protein deposition is enhanced at the expense of carcass fat and in part, visceral tissue.     

Effect of chromium propionate and metabolizable energy on growth,carcass traits,and pork quality of growing-finishing pigs

An experiment was conducted to evaluate the dietary effects of Cr propionate (CrProp) and metabolizable energy (ME) on growth, carcass traits, and pork quality of growing-finishing pigs. One hundred forty-four Cambrough-22 barrows were allotted to four dietary treatments in a randomized complete block design (six replicates of six pigs per replicate; average initial and final body weight were 27 and 113 kg, respectively). The dietary treatments were: 1) corn-soybean meal basal (B; low ME), 2) B + 200 ppb of Cr (as CrProp), 3) B + 200 kcal ME/kg (4.5% added fat; high ME), or 4) B + 200 kcal ME/kg + 200 ppb of Cr. At trial termination, three pigs per replicate were killed to determine dietary effects on carcass traits and pork quality. Overall average daily gain, average daily feed intake, and gain:feed ratio were not affected (P > 0.10) by diet. During the early growing period, average daily gain was increased in pigs fed the CrProp-low-ME diets, but decreased in pigs fed the CrProp-high ME diets (Cr x ME, P < 0.04). Feed intake was increased (P < 0.05) in pigs fed the high-ME diets during the early growing period. Forty-five min and 24 h pH were not affected (P > 0.10) by diet. The CIE L* tended (P = 0.07) to be increased and shear force tended (P = 0.06) to be decreased in pigs fed high-ME diets. Subjective marbling was increased (P < 0.03) and longissimus muscle percentage moisture and thaw loss were decreased (P < 0.04) in pigs fed CrProp. Chromium propionate had no consistent effect on growth and carcass traits in this experiment; however, CrProp did affect some aspects of pork quality.     

品种和营养水平对猪生长性能、胴体性状和肉质的影响

本试验旨在研究品种和营养水平对猪生长性能、胴体性状和肉质的影响。选择12对初始体重为(61.16±4.13)kg的高坡猪和"杜×长×太"三元杂交猪(DLT),随机分成4个处理,饲喂不同营养水平[NRC(2012)、中国猪饲养标准(2004)]的全价饲粮,试验猪平均体重达90 kg时屠宰。结果表明:DLT的眼肌面积显著高于高坡猪(P0.05),而肌内脂肪含量、平均背膘厚、肉色的亮度(L*)24 h和黄度(b*)24 h显著低于高坡猪(P0.05);饲喂高营养水平的饲粮可以显著降低猪的料重比(P0.05);饲粮营养水平升高显著提高了高坡猪的平均日增重、平均日采食量、胴体长和肉色的红度(a*)24 h(P0.05),显著降低了肉色的L*24 h、滴水损失以及背最长肌固醇调节元件结合蛋白-1c和激素敏感性脂肪酶mRNA的相对表达量(P0.05);饲粮营养水平升高显著降低了DLT肉色的a*45 m in和a*24 h(P0.05)。综上所述,在本试验条件下,品种和营养水平对猪生长性能、胴体性状和肉质有显著影响;DLT胴体性状优于高坡猪,肉质反之。饲粮营养水平升高显著提高了DLT胴体性状和高坡猪的肉质,对生长性能有一定的改善。     

Growth performance and carcass traits of pigs subjected to marginal dietary restrictions during the grower phase.

Sixty-four individually housed pigs were used to investigate the effect of amino acid content of finisher diets on growth performance of pigs subjected to marginal dietary amino acid restrictions (80% of the 1988 NRC lysine recommendation) during the grower phase. In each of the two trials, low- and high-amino-acid grower diets (.421 and .765 g lysine/MJ DE, respectively) and four finisher diets (.421, .516, .612, and .707 g lysine/MJ DE) were randomly assigned within sex to 16 gilts and 16 castrated males weighing 23.0 +/- 2.0 kg in a 2 x 4 factorial arrangement of treatments. The average weight of pigs after a completion of diet change was 50.4 +/- 2.1 kg. All pigs were slaughtered at an average weight of 105.2 +/- 4.1 kg. Ultrasound backfat thickness was measured at the time of diet change and before slaughter. Pigs were allowed ad libitum access to feed and water. During the grower phase, pigs fed the high-amino-acid diet grew faster (P < .001) and more efficiently (P < .001) and had less ultrasound backfat (P < .001) than those fed the low-amino-acid diet. The grower diet had no effect on weight gain during the finisher phase. Consequently, pigs fed the high-amino-acid grower diet had better overall weight gain (P < .01) than those fed the low-amino-acid diet. The rate of lean accretion was, however, similar between the two groups of pigs. Furthermore, pigs fed the low-amino-acid grower diet seemed to have better carcass quality, as indicated by less ultrasound backfat (P < .01) and larger carcass longissimus muscle area (P < .05). Average and 10th rib carcass backfat decreased linearly (P < or = .05) and lean accretion rate improved linearly (P < .05) as the amino acid content of finisher diets increased, but there was no grower x finisher diet interaction in these and other response criteria. Although no evidence of compensatory weight gain was observed, it is possible that compensatory lean tissue growth may have occurred in pigs subjected to early amino acid restrictions at the expense of fatty tissue growth.     

Effect of dietary lysine level and environmental temperature during the finishing phase on the intramuscular fat content of pork

This study was designed to investigate the effects of dietary lysine level on the intramuscular fat content of the longissimus in finishing pigs reared at two environmental temperatures. Seventy-two hybrid gilts were individually penned and given ad libitum access to either a diet formulated to meet their lysine requirement (6.4 g/kg lysine) or a lysine-deficient diet (4.8 g/kg). Pigs were held at one of two environmental temperatures (thermoneutral [18 degrees C] or hot [32 degrees C]). The study was carried out between approximately 90 and 126 kg live weight; pigs in the thermoneutral and hot environments were on test for 5 and 7 wk, respectively. There were no interactions between dietary lysine level and environmental temperature. Dietary lysine content did not influence feed intake or average daily gain; however, pigs on the lysine-deficient diet had a poorer gain:feed ratio than those fed to requirement (P < .01). High environmental temperature decreased feed intake (P < .001) and average daily gain (P < .01) but improved gain:feed ratio (P < .01). Backfat at the 10th rib was increased and loin eye area and estimated percentage lean in the carcass were decreased for pigs on the lysine-deficient diet. The higher environmental temperature resulted in an increase in carcass length but had no effect on other carcass measurements or intramuscular fat. Feeding the lysine-deficient diet resulted in an increase of .55 percentage unit in longissimus intramuscular fat content (P < .01); however, there was no difference in subjective marbling scores between the diets. Warner-Bratzler shear force values were not affected by dietary lysine level or environmental temperature. Results from this study suggest that feeding of lysine-deficient diets at the end of the finishing period can increase intramuscular fat deposition under thermoneutral and hot conditions.     

Effects of supplementation of high-dosing Trichoderma reesei phytase in the corn-wheat-soybean meal-based diets on growth performance,nutrient digestibility,carcass traits,faecal gas emission,and meat quality in growing-finishing pigs

We conduct this study to investigate the effects of corn-wheat-soybean meal (SBM)-based diet supplemented with high-dosing Trichoderma reesei phytase on the growth performance, nutrient digestibility, carcass traits, faecal gas emission and meat quality in growing-finishing pigs (29.71–110.58 kg live weight; 70-day-old to 166-day-old). A total of 56 crossbred pigs [(Landrace × Yorkshire) × Duroc] were used in 96-day experiment with a completely randomized block design. The growing period was from day 0 to 42, and the finishing period was from day 43 to 96. Pigs were randomly allocated to one of two treatments with seven replicate pens and four pigs (two barrows and two gilts) per pen and fed corn-wheat-SBM-based nutrient adequate basal diet or the basal diet supplemented with 1500 FTU/kg diet Trichoderma reesei phytase. One phytase unit (FTU) was defined as the amount of enzyme that catalyses the release of one micromole phosphate from phytate per minute at 37°C and pH 5.5. Dietary supplement with Trichoderma reesei phytase had increased body weight on day 96 and average daily gain in days 0–96. Moreover, high apparent total tract digestibility (ATTD) of phosphorus (P) was observed in pigs fed with Trichoderma reesei phytase. However, the carcass traits, faecal gas emission and meat quality of pigs were unaffected by Trichoderma reesei phytase supplementation. In conclusion, supplementation of high-dosing Trichoderma reesei phytase (1500 FTU/kg diet) in the corn-wheat-SBM-based nutrient adequate basal diet increased body weight and the ATTD of P, while no adverse effects were observed on the production characteristics.