不同净能水平和赖氨酸净能比的低蛋白日粮对肥育猪生长性能和胴体品质的影响

选用61.08 kg杜×长×大三元杂交猪540头,随机分为9个处理,每处理6个重复,每重复10头猪,公、母各半。采用3×3两因素设计,日粮蛋白水平降低4个百分点,净能为9.83、10.04、10.25 MJ/kg,赖氨酸净能比为0.76、0.84、0.91 g/MJ,研究净能和赖氨酸净能比对肥育猪生长性能和胴体品质的影响。结果表明:在60~100 kg阶段,10.04 MJ/kg净能组的ADG显著高于9.83 MJ/kg组的(P<0.05);赖氨酸净能比为0.84 g/MJ组的ADG显著高于0.76 g/MJ组(P<0.05);二者互作不影响生长性能和胴体品质(P>0.05),综合评定在60~100 kg阶段,猪的低蛋白日粮净能水平和赖氨酸净能比分别为10.04 MJ/kg和0.84 g/MJ为宜。     

日粮中谷物组成和复合酶添加对生长猪生产性能和养分消化率的影响

选用体重约20kg的杜×长×大三元杂交生猪108头,随机分成9个处理组,每组3个重复,每重复4头猪,公母比为1:1。采用2×3试验设计研究了日粮中不同谷物组成和不同复合酶的添加水平对生长猪生产性能和养分消化率的影响。结果表明:(1)日粮中谷物组成显著影响生长猪的日增重、料肉比和营养物质消化率(P<0.05)。随着日粮中谷物组成的小麦比例的增多,生长猪的日增重会降低而料肉比会相应提高,能量、干物质、蛋白质和粗纤维的消化率会显著降低;(2)添加复合酶制剂能显著提高能量、干物质、蛋白质和粗纤维的消化率,从而提高生长猪的日增重和降低料肉比。随着复合酶添加量的增加,生长猪的日增重和养分消化率均显著提高(P<0.05),而料肉比显著降低(P<0.05),但复合酶的两个添加水平(0.025%和0.05%)之间无显著差异(P>0.05)。(3)小麦占日粮谷物组成的38%和添加0.025%复合酶的饲粮与玉米豆粕型日粮相比,生长猪的日增重与能量、干物质、蛋白质的消化率均有所提高(P>0.05),粗纤维的消化率显著提高(P<0.05),而料肉比显著降低(P<0.05)。因此,在本试验条件下,生长猪日粮中小麦占谷物的的比例以38%左右较为适宜,复合酶的适宜添加水平为0.025%。     

植酸酶和磷酸氢钙对育肥猪生长性能和养分消化率的影响

采用体重75 kg的长白×大约克二元杂交阉公猪56头,随机分为4个处理,分别饲喂常磷日粮、低磷日粮、常磷加植酸酶日粮和低磷加植酸酶日粮。每个处理14个重复,每个重复1头,研究杂粕型日粮添加植酸酶(750 U/kg)和不添加磷酸氢钙对育肥猪的生产性能和养分消化率的影响。结果表明:低磷组比常磷组的采食量降低了5.04%(P<0.05),料重比增加了17.94%(P<0.01),日增重降低了19.80%(P<0.01),单位增重饲料成本增加了17.20%(P<0.01),磷表观消化率降低了10.16%(P<0.01),钙表观消化率降低了8.56%(P<0.05),粗蛋白表观消化率无显著变化(P>0.05);常磷加酶组比常磷组的采食量增加了2.97%(P>0.05),料重比增加了3.53%(P>0.05),日增重降低了1.70%(P>0.05),单位增重饲料成本增加了4.12%(P>0.05),磷表观消化率降低了3.46%(P>0.05),钙表观消化率降低了4.40%(P>0.05),粗蛋白表观消化率无显著变化(P>0.05);低磷加酶组比低磷组的采食量增加了7.50%(P<0.01),料重比降低了13.47%(P<0.01),日增重增加了24.30%(P<0.01),单位增重饲料成本降低了13.60%(P<0.01),磷表观消化率提高了42.09%(P<0.01),钙表观消化率提高了11.18%(P<0.01),粗蛋白表观消化率无显著变化(P>0.05);低磷加酶组(即无磷酸氢钙日粮加酶组)与常磷组相比采食量、日增重、料重比和单位增重饲料成本均差异不显著(P>0.05),磷表观消化率提高了27.66%(P<0.05),钙表观消化率提高了1.68%(P>0.05),粗蛋白表观消化率无显著变化(P>0.05)。结论:低磷日粮添加植酸酶可以提高猪生长性能,提高钙磷表观消化率,但对粗蛋白表观消化率无显著影响;常磷日粮添加植酸酶对猪的生长性能和养分表观消化率均无显著影响;不添加磷酸氢钙会降低猪的生长性能和钙磷的表观消化率。     

磷缺乏日粮添加米糠和植酸酶对生长猪养分利用率及氮磷代谢的影响

文章旨在研究日粮添加不同水平米糠及植酸酶对生长猪养分消化率及钙磷代谢的影响。试验选择48头平均体重为(87.0±2.45)kg的生长猪,随机分为6组,每组4个重复,每个重复2头猪。对照组饲喂玉米-豆粕型基础日粮,处理组用7.5%、15%、30%的米糠替代基础日粮,同时另外两组在对照组和30%米糠组分别添加750IU/kg植酸酶,试验共进行2周,包括1周适应期和1周试验期。结果显示:随着日粮米糠添加水平的升高,干物质、能量、氮、纤维、钙表观消化率显著线性升高(P<0.05),而磷表观消化率显著线性降低(P<0.05)。随着日粮米糠添加水平的升高钙沉积率显著升高(P<0.05),对磷代谢平衡其他指标均具有显著升高的影响(P<0.05),粪氮量显著升高(P<0.05),其他氮平衡指标显著降低(P<0.05)。日粮添加植酸酶显著提了磷、脂肪和钙表观消化率(P<0.05),而米糠添加水平显著提高了养分表观消化率(P<0.05)。米糠替代基础日粮添加植酸酶显著提高了钙沉积率(P<0.05),显著提高了磷的吸收和沉积量(P<0.05)。结论:猪日粮中添加米糠较玉米-豆粕型日粮降低了磷表观消化率,添加植酸酶后可以改善氮、磷代谢。     

日粮消化能水平对四川白兔生产性能和养分消化率的影响

为研究日粮消化能水平对四川白兔生产性能和养分消化率的影响,本试验选择480只30日龄断奶四川白兔,随机分成4个处理组,每个处理10个重复,每个重复12只,分别饲喂含9.50、10.00、10.50、11.00 MJ/kg消化能的日粮,饲养试验持续10周。结果表明:消化能水平对四川白兔日增重、料重比、腹泻率和死亡率影响显著(P0.05),对采食量影响不显著(P0.05),随着日粮消化能水平的增加,日增重呈先增加后减少的趋势,料重比呈先减少后增加趋势,腹泻率和死亡率呈逐渐增加的趋势,10.00 MJ/kg组生产性能最佳;消化能水平对四川白兔日粮干物质、粗蛋白质和粗纤维消化率影响显著(P0.05),对粗脂肪和粗灰分消化率影响不显著(P0.05),其中干物质和粗蛋白质消化率随着消化能水平的增加呈先升高后降低的趋势,而粗纤维消化率呈逐渐降低的趋势。综合来看,在本试验条件下,四川白兔日粮消化能适宜水平为10.00 MJ/kg。     

不同净能水平日粮对不同体重阶段猪生长性能和能量摄入量的影响

试验旨在研究不同净能水平的日粮对不同体重阶段猪的生长性能和能量摄入量的影响。试验1选择12头初始体重（24.50±0.96）kg的杜×长×大三元杂交健康去势公猪，随机分为3组，每组4个重复，每个重复1头猪。3个日粮处理分别为低净能水平日粮（9.63 MJ/kg）、中净能水平即对照组日粮（10.26 MJ/kg）和高净能水平日粮（10.89 MJ/kg）。试验采用拉丁方设计连续进行7期，每6天为1期。试验2选择180头体重（75.4±1.4）kg的三元杂交健康猪，按体重和性别将猪随机分为5个组，每组5个重复，每个重复6头猪（3公3母），日粮净能水平分别为8.87、9.14、9.41、9.69、9.96 MJ/kg。试验1结果表明：相较于对照组，高净能组与低净能组猪的日采食量下降（P<0.05）；高净能组的饲料转化率和日增重均高于低净能组（P<0.05）。试验2结果表明：猪日粮净能值为9.69、9.96 MJ/kg时，猪的耗料增重比最低（P=0.09）。由此可见，日粮净能水平的增加会降低猪的采食量，改善饲料转化率；猪体重阶段在75～100 kg时，适宜的日粮净能水平为9.69 ...     

低营养水平饲粮添加单一或复合非淀粉多糖酶对生长肥育猪生长性能、养分消化率和肉品质的影响

为研究低营养水平饲粮添加单一或复合非淀粉多糖酶对生长肥育猪生长性能、养分消化率和肉品质的影响,试验选择体重(47.5±1.3)kg的200头健康杜长大三元杂种生长猪,按体重相近、公母各半的原则,随机分为4组,每组5个重复,每个重复10头生长猪。正对照组饲喂基础饲粮,负对照组饲喂低营养水平饲粮,单一酶制剂组饲喂负对照组饲粮+500 g/t甘露聚糖酶,复合酶制剂组饲喂负对照组饲粮+500 g/t复合非淀粉多糖酶(主要为甘露聚糖酶和半乳糖苷酶)。预试期3 d,正式试验期70 d。结果表明:1)与负对照组相比,正对照组、单一酶制剂组和复合酶制剂组显著提高了末重、日增重,并显著降低了料重比;2)35 d时,正对照组和单一酶制剂组对干物质的表观消化率显著高于负对照组和复合酶制剂组(P<0.05);3)35 d时,正对照组和复合酶制剂组对氮和总能的表观消化率显著高于负对照组和单一酶制剂组(P<0.05);4)各处理组对猪肉品质无显著影响(P>0.05)。试验结果表明在该试验条件下,低营养水平饲粮降低了生长肥育猪的生长性能和养分表观消化率,而在生长肥育猪低营养水平饲粮中添加单一或复合非淀粉多糖酶都可以部分提高生长性能和养分表观消化率,且对猪肉品质无影响。     

能量水平对生长猪生产性能、养分消化率和血清生化指标的影响

选择体重(20.40±2.57)kg的健康渝荣1号配套系商品猪60头,随机分为5组,分别饲喂消化能浓度为13.19、14.10、14.35、14.69 MJ/kg和14.90 MJ/kg的饲粮,测定其生产性能和血清生化指标;同时进行消化试验,测定饲粮的养分消化率。结果表明:采食量和饲料增重比随消化能水平上升而下降,14.90 MJ/kg组采食量极显著低于13.19 MJ/kg组(P<0.01),14.69 MJ/kg组和14.90 MJ/kg组饲料增重比显著低于13.19 MJ/kg组(P<0.05);14.69 MJ/kg组日增重最高(P>0.05)。14.90 MJ/kg组血清总胆固醇浓度显著高于13.19 MJ/kg组和14.10 MJ/kg组(P<0.05)。各常规养分消化率随消化能水平提高而上升。由此可见,提高生长猪饲粮能量水平,能够提高营养物质的消化率、降低采食量和饲料增重比;在本试验条件下,消化能水平为14.69 MJ/kg时日增重最佳。     

低蛋白质水平日粮对育肥猪养分消化率血浆生化指标和生长性能的影响

为探究低蛋白质水平日粮对育肥猪养分消化率、血浆生化指标和生长性能的影响,笔者进行相关试验。选择120头健康状况良好的育肥猪,随机分为2个组,每组4个重复,每个重复15头,对照组饲喂蛋白质水平为16%的基础日粮;试验组饲喂蛋白质水平为14%并添加合成氨基酸的基础日粮。试验期49 d。结果表明：低蛋白质水平日粮对育肥猪的养分消化率、血浆生化指标和生长性能无显著影响（P>0.05）,试验组的谷草转氨酶和碱性磷酸酶含量较对照组分别降低了16.59%(P<0.05)和11.71%(P<0.05)。说明日粮蛋白质水平降低2个百分点并添加合成氨基酸不会影响育肥猪生长性能,且能够有效减少蛋白质饲料的使用量,从而降低氮的排放量。     

水合硅铝酸钠钙对生长肥育猪生长性能、养分表观消化率及抗氧化能力的影响

本试验旨在研究水合硅铝酸钠钙(HSCAS)对生长育肥猪生长性能、养分表观消化率及抗氧化能力的影响。选择(48.0±10.0)kg的健康"杜×长×大"生长猪45头,随机分为3个处理,每个处理5个重复,每个重复3头猪。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加0.25%和2.50%HSCAS的饲粮。试验期为70d,分为48～80kg(前期)和81～110kg(后期)2阶段进行。结果表明:1)与对照组相比,添加0.25%HSCAS对猪生长性能、血清尿素氮(UN)含量和抗氧化能力均无显著影响(P>0.05),但显著降低了后期粗蛋白质(CP)和能量的表观消化率(P<0.05);2)与对照组相比,添加2.50%HSCAS显著提高了后期和全期的料重比(P<0.05),显著提高了血清UN含量(P<0.05),显著降低了后期生长育肥猪CP、粗灰分和能量的表观消化率、血清超氧化物歧化酶活性及总抗氧化能力(P<0.05)。由此可知,饲粮中添加0.25%HSCAS对生长育肥猪的生长和健康无明显影响,但添加量达到2.50%可显著降低其生长性能、养分表观消化率和抗氧化能力。     

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.     

热应激条件下日粮消化能水平对肉兔生产性能和养分消化率的影响

试验旨在研究热应激条件下日粮消化能水平对肉兔生产性能和饲粮养分消化率的影响。选择30日龄断奶新西兰兔150只,随机分成5个处理组,每个处理5个重复,每个重复6只兔,分别饲喂8.79、9.62、10.46、11.30MJ/kg和12.13 MJ/kg消化能的饲粮。结果显示,热应激条件下,随着日粮消化能的增加,肉兔采食量和料重比均一定程度下降(P>0.05或P<0.05),日增重呈先升高后降低的趋势;干物质、粗蛋白质和粗灰分消化率随着消化能水平的提高,呈现先上升后下降的趋势,粗脂肪和粗纤维的消化率随着消化能水平的提高,呈现逐渐升高的趋势。综合来看,在热应激条件下肉兔饲粮的消化能水平以10.46～11.30 MJ/kg为宜。     

Effects of formulating growing pig diet with increasing levels of wheat‐corn distillers dried grains with solubles on digestible nutrient basis on growth performance and nutrient digestibility

Formulating swine diets containing fibrous coproducts based on net energy (NE) and standardized ileal digestible amino acid (SID AA) values is recommended for optimizing pig performance. However, the effects of applying this approach to diets with increasing dietary levels of wheat‐corn‐derived distillers dried grains with soluble (wcDDGS) on pig performance have not been evaluated. Thus, 48 pigs with an average body weight [BW] of 25.5 kg were used to determine the effects of increasing wcDDGS (1:1 wheat to corn ratio) content in grower diets on performance and apparent total tract digestibility (ATTD) of energy and nutrients. Pigs were housed in pens of either 2 barrows or gilts balanced for BW and fed 4 diets within sex for 42 days. Diets were a nutrient adequate corn–barley–soybean meal‐based diet with 0%, 10%, 20% and 30% wcDDGS, and were similar in calculated NE and SID AA values. Acid insoluble ash was used as the indigestible marker. Final BW and overall average daily gain (ADG) linearly decreased (p < 0.05) and feed efficiency tended to decrease (p = 0.07) with increased dietary wcDDGS. Overall average daily feed intake was not affected (p > 0.10) by dietary treatment. The ATTD of dry matter and energy linearly decreased (p < 0.01), whereas the ATTD of neutral detergent fibre linearly increased (p < 0.01) with increasing dietary level of wcDDGS. Increasing dietary wcDDGS content did not affect (p > 0.10) ATTD of Ca and P. In conclusion, increasing dietary wcDDGS content reduced growth performance and ATTD of energy in growing pigs. Thus, the risks of high dietary wcDGGS content may not be completely alleviated by formulating growing pig diets on the basis of NE and SID AA systems.     

浓缩脱酚棉籽蛋白生长猪消化能评定及其对仔猪生长性能、血清生化指标和养分表观消化率的影响

本研究旨在通过猪消化代谢试验测定浓缩脱酚棉籽蛋白(CDCP)生长猪消化能,同时研究其对仔猪生长性能、血清生化指标和养分表观消化率的影响.试验选取65日龄、体重(38.80±2.60)kg的"杜×(长×大)"健康阉公猪8头,随机分成2组(每组4个重复,每个重复1头猪),分别饲喂基础饲粮和试验饲粮(80％基础饲粮+20％C...     

饲喂脆茎全株水稻对生长肥育猪生长性能、养分消化和胴体品质的影响

体重相近的杜洛克生长母猪54头，随机分成3组（每组3个重复），研究脆茎全株水稻（3个水平0、10％和20％）用于生长肥育猪日粮，对猪的生长性能、养分消化、胴体品质和肉质的影响。结果表明，生长猪阶段（29～52kg）对照组、10％组和20％组的采食量、平均日增重和料重比均无显著差异（P〉0．05）。肥育猪阶段（54～85kg）采食量和平均日增重，20％组显著低于对照组（P〈0．01），10％组与对照组之间无显著差异（P〉0．05）；各组料重比均无显著差异（P〉0．05）。生长猪阶段10％组和20％组各种养分的消化率都低于对照组；而肥育猪阶段，两组NDF消化率显著低于对照组（P〈0．01），其它养分消化率与对照组无显著差异。与对照组相比，10％组和20％组屠宰率有所下降，而瘦肉率提高，眼肌面积增大，背膘厚降低，但差异均不显著（P〉0．05）。10％组和20％组的背最长肌蛋白含量增加，脂肪含量降低，其中20％组与对照组差异显著（P〈0．05）；滴水损失和大理石纹及肉色评分各组之间均无显著差异（P〉0．05），20％组宰后24h的pH，显著高于对照组（P〈0．01）。     

Apparent ileal digestibility of amino acids and the digestible and metabolizable energy content of high-oil corn varieties and its effects on growth performance of pigs.

Two experiments were conducted to compare the nutritional value of normal and high-oil corn for pigs. The normal corn and the two varieties (high-oil corns A and B) of high-oil corn contained 4.41, 7.35 and 8.86% ether extract, on DM basis, respectively. In experiment 1, six non-littermate crossbred barrows (37.8 +/- 1.3 kg BW) were fitted with ileal T-cannulas and used in a double replicated Latin Square digestion trial. Three diets were formulated containing 96.6% of one of the three varieties of corn as the only protein source. Chromic oxide (0.4%) was added as a digestibility marker. Additional vitamins and minerals were added to meet requirements. The digestible energy concentrations for normal corn and high-oil corn A and B were 16.53, 16.99 and 17.07 MJ/kg while the metabolizable energy values were 15.82, 16.32 and 16.36 MJ/kg, on DM basis, respectively. The ileal amino acid digestibility of high-oil corn was generally higher than that of normal corn with significant differences being observed for the essential amino acids isoleucine and phenylalanine. In experiment 2, 96 pigs (8.01 +/- 0.14 kg BW) were used to evaluate four diets in a 2 x 2 factorial design conducted over a 35-day period. Corn variety (high-oil vs. normal corn) and nutrient density (high content of protein and ME vs. low content of protein and ME) were set as the two main effects. During the first 14 days, pigs fed high-oil corn diets consumed more feed and tended to get higher daily gain than pigs fed normal corn. Over the entire 35-day experiment, increasing dietary nutrient density increased daily gain and tended to increase feed conversion, while variety of corn had no significant effects on performance. Overall, the present results indicate that the energy concentration and ileal amino acid digestibility of high-oil corn varieties were equal or superior to those in normal corn and therefore they should be able to be effectively utilized in diets fed to swine.     

Effect of a novel consensus bacterial 6-phytase variant in grower pigs fed corn-soybean meal-based diets formulated with a full nutrient matrix and no added inorganic phosphorus

The capacity of a novel consensus bacterial 6-phytase variant (PhyG) to entirely replace dietary inorganic phosphorus (Pi) source in grower pigs fed diets with reduction of calcium (Ca), net energy (NE), and digestible amino acids (AA) was evaluated, using growth performance and apparent total tract digestibility (ATTD) of nutrients as outcome measures. A total of 352 mixed-sex pigs (initial BW 23.4 kg) were randomized to 4 treatments, 8 pigs/pen, and 11 pens/treatment. Diets were corn-soybean meal-based and formulated by phase (grower 1, 25 to 50 and grower 2, 50 to 75 kg BW). The positive control diet (PC) provided adequate nutrients and a negative control diet (NC) was formulated without Pi (1.2 g/kg ATTD P) and reduced in Ca (-0.12 to -0.13 percentage points), NE (-32 kcal/kg), and digestible essential AA (-0.004 to -0.026 percentage points) vs. PC. Two further treatments comprised the NC plus 500 or 1,000 FTU/kg of PhyG. Data were analyzed by ANOVA, mean contrasts and orthogonal polynomial regression. Nutrient reductions in the NC reduced (P < 0.05) average daily gain (ADG) during grower 1 and overall (73 to 136 d of age), increased (P < 0.05) feed conversion ratio (FCR) during grower 1 and overall and tended to reduce (P < 0.1) average daily feed intake (ADFI) during grower 2 and overall, vs. PC. Phytase supplementation improved (P < 0.05) FCR during grower 1, ADG during grower 2 and overall, ATTD of DM and P, and tended to improve DE (P = 0.053) in a linear dose-dependent manner. PhyG at 1,000 FTU/kg resulted in growth performance (all measures, all phases) equivalent to PC. The findings demonstrate that PhyG at 1,000 FTU/kg totally replaced Pi in complex grower pig diets containing industrial co-products, compensated a full nutrient matrix reduction and maintained performance.     

Standardized ileal protein and amino acid digestibility by growing pigs and sows

Experiments were conducted to determine the effect of the physiological condition of swine on standardized ileal digestibility coefficients (SID). The apparent ileal digestibility coefficients were determined for crude protein and amino acids in six feed ingredients (corn, barley, wheat, soybean meal, canola meal, and meat and bone meal) in growing pigs and in gestating and lactating sows. Growing pigs and lactating sows were given free access to their diets, whereas gestating sows were allowed to consume only 2 kg of feed daily. The nonspecific (basal) endogenous losses of protein and amino acids were determined under similar feeding regimens after feeding a protein-free diet. The SID for crude protein and amino acids were calculated by correcting the apparent ileal digestibility coefficients for the nonspecific endogenous losses of protein and amino acids. With a few exceptions, there were no differences (P > 0.05) in the SID for crude protein and amino acids between growing pigs and lactating sows. Overall, gestating sows had higher (P < 0.05) SID for crude protein and all amino acids, except for tryptophan and aspartate, compared with growing pigs. Likewise, the SID of most amino acids obtained by gestating sows were higher (P < 0.05) than those obtained by lactating sows. Interactions (P < 0.05) between animals and diets were observed for gestating sows compared with growing pigs as well as gestating sows compared with lactating sows. As a consequence, it is not possible to extrapolate data from one feed ingredient to another. On most occasions, the lowest SID among the indispensable amino acids was calculated for threonine, valine, and lysine. It is concluded that gestating sows fed 2 kg of feed per day have higher standardized digestibility coefficients than do growing pigs and lactating sows given free access to their diets. This difference may be due to differences in daily feed intake rather than to the physiological status of the animals.     

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.