丙氨酰谷氨酰胺对断奶仔猪生长和血清抗氧化能力的影响

本试验旨在研究丙氨酰谷氨酰胺(Ala-Gln)对断奶仔猪生长及抗氧化能力的影响.试验选择经产母猪产的大×长二元杂交仔猪48头(公母各占1/2),21 d断奶,按公母比例一致,同窝次均分的原则,随机分成4个处理,每个处理12个重复,每个重复1头猪.A组为对照组,饲喂基础日粮;B、C和D组为试验组,分别饲喂在基础日粮中添加0.1%、0.3%和0.5% Ala-Gln的H粮.试验结果表明,随日粮Ala-Gln添加水平提高,21～31 d时,仔猪的平均日增重以二次曲线方式提高(P=0.04),31～41 d和21～41 d时,仔猪的平均日增重均以线性方式提高(P=0.07和P=0.05);31 d时,添加0.5%的Ala-Gln显著降低仔猪血清尿素氮(BUN)含量(P<0.05),且随着日粮Ala-Gln添加水平提高,仔猪BUN含量以线性方式降低(P=0.06);添加Ala-Gln对仔猪血清过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活力、总抗氧化能力(T-AOC)和血清丙二醛(MDA)含量均有不同程度的影响,其中添加0.1%、0.3%和0.5%的Ala-Gln均显著提高仔猪血清GSH-Px活力(P<0.05),且在31和41 d时,血清GSH-Px活力以线性方式升高(P=0.01和P=0.05).结果提示,断奶仔猪日粮中添加Ala-Gln能促进体内蛋白质合成,提高血清抗氧化能力,促进仔猪生长.     

N-氨甲酰谷氨酸对断奶仔猪生长性能、养分消化率及血清游离氨基酸含量的影响

本研究旨在探讨不同水平N-氨甲酰谷氨酸(NCG)对断奶仔猪生长性能、养分消化率及血清游离氨基酸的影响.试验选取60头平均体重为(6.4±0.7)kg的26日龄断奶仔猪,按完全随机区组设计分为4个处理,每个处理5个重复,每个重复3头仔猪,分别饲喂含NCG为0、0.04%、0.08%或0.12%的玉米-豆粕型饲粮.结果表明:1)随着NCG添加量的升高,除26～40日龄断奶仔猪平均日增重外,其他日龄阶段仔猪平均日增重和料重比均呈显著的二次曲线改善规律(P<0.05),其中,0.04%和0.08%的NCG对仔猪的促生长效果显著(P<0.05);2)饲粮中添加0.04%、0.08%和0.12%的NCG,仔猪对饲粮粗蛋白质和磷的消化率呈提高趋势(P>0.05);3)饲粮中补充低剂量(0.04%)的NCG可显著改善仔猪腹泻状况(P<0.05),与其相比,高剂量(0.12%)的NcG导致26～47日龄仔猪腹泻指数的显著升高(P<0.05);4)随着饲粮中NCG添加量的增加,仔猪血清游离精氨酸的含量呈线性升高趋势(P=0.077),其中NCG达0.08%以上时,血清游离精氨酸显著高于对照组(P<0.05).由此可知,饲粮中添加0.04%和O.08%的NCG能显著改善断奶仔猪的生长性能和腹泻状况.综合促生长效果和经济成本,断奶仔猪饲粮中NCG的添加量以0.04%最为合适.     

复合非淀粉多糖酶对断奶仔猪生长性能和血清生化指标的影响

为了研究不同复合木聚糖酶和β-甘露聚糖酶对断奶仔猪生长性能和血液生化指标的影响,选择72头体重(6.75±0.26)kg"杜×长×大"断奶仔猪,分为3个处理,每个处理4个重复,每个重复6头猪,对照组饲喂基础日粮(CT),试验1组饲喂基础日粮+0.5%复合酶1(E1),试验2组饲喂基础日粮+0.5%复合酶2(E2)。结果显示:与对照组相比,试验1组能显著提高断奶仔猪平均日增重(P<0.05),试验2组能显著提高断奶仔猪平均日增重(P<0.05)、降低料肉比(P<0.05);试验1组能显著提高断奶仔猪血清总蛋白、白蛋白浓度(P<0.05),降低血清尿素氮浓度(P<0.05);试验2组能显著提高断奶仔猪血清总蛋白(P<0.01)、白蛋白浓度和碱性磷酸酶活性(P<0.05),降低血清尿素氮浓度(P<0.05)。说明日粮中添加酶制剂可以调节血清中蛋白质代谢相关指标,提高断奶仔猪的生长性能。     

外源核苷酸对断奶仔猪内脏器官重量、血清指标及空肠黏膜二糖酶活性的影响

选用21±2日龄断奶仔猪160头,随机分为2组,每组设4个重复.对照组饲喂基础日粮,试验组在基础日粮中添加0.2%核苷酸,饲养期21 d.研究外源核苷酸对断奶仔猪内脏器官重、血清指标和空肠黏膜二糖酶活性的影响.结果表明:日粮中添加核苷酸可显著提高仔猪断奶后第7 d胰腺率(P<0.05),并具有提高仔猪断奶后第14 d肝脏指数、脾脏指数趋势(P>0.05);可极显著提高仔猪断奶后第21 d血清总蛋白和血清白蛋白(P<0.01);并可显著提高仔猪断奶后第14 d空肠粘膜蔗糖酶活性(P<0.05).     

外源核苷酸对断奶仔猪内脏器官重量、血清指标及空肠黏膜二糖酶活性的影响

选用21±2日龄断奶仔猪160头,随机分为2组,每组设4个重复。对照组饲喂基础日粮,试验组在基础日粮中添加0.2%核苷酸,饲养期21 d。研究外源核苷酸对断奶仔猪内脏器官重、血清指标和空肠黏膜二糖酶活性的影响。结果表明:日粮中添加核苷酸可显著提高仔猪断奶后第7 d胰腺率(P<0.05),并具有提高仔猪断奶后第14 d肝脏指数、脾脏指数趋势(P>0.05);可极显著提高仔猪断奶后第21 d血清总蛋白和血清白蛋白(P<0.01);并可显著提高仔猪断奶后第14 d空肠粘膜蔗糖酶活性(P<0.05)。     

低聚木糖对仔猪生产性能和血清生化指标的影响

本试验旨在研究低聚木糖对早期断奶仔猪生长性能和血清生化指标的影响。选用72头35日龄断奶,体重相近(10kg左右)的健康三元(杜×长×大)杂交仔猪,随机分成4个处理,每处理3个重复,每重复6头猪。以玉米-豆粕型日粮为基础日粮,对照组饲喂基础日粮,试验组为分别在基础日粮基础上添加0.01%、0.02%、0.04%低聚木糖。试验期28d。研究结果表明:①相对于对照组,0.02%低聚木糖组日增重提高15.34%(P<0.05),0.01%、0.02%低聚木糖组料重比显著降低(P<0.05),各试验组仔猪腹泻率均极显著降低(P<0.01);②各试验组仔猪的血清尿素氮和总胆固醇含量与对照组比较差异均显著(P<0.05),0.02%低聚木糖组血糖含量比对照组提高7.83%(P<0.05),血清总蛋白、血清白蛋白含量都有升高的趋势,但差异不显著(P>0.05);③0.02%低聚木糖组的淀粉酶和碱性磷酸酶活性比对照组有显著提高(P<0.05),各试验组与对照组之间谷丙转氨酶和谷草转氨酶活性无显著性差异(P>0.05)。④各试验组与对照组相比,断奶仔猪血清中IgG水平都显著提高(P<0.05)。除了0.01%低聚木糖组IgA略...     

稀土壳糖胺螯合盐对断奶仔猪生长性能、血清生化指标、营养物质消化率及粪中微生物菌群的影响

本试验旨在研究饲粮中添加稀土壳糖胺螯合盐(rare earth-chitosan chelate,RECC)对断奶仔猪生长性能、血清生化指标、营养物质消化率及粪中微生物菌群的影响。试验选取240头28日龄健康纯种大白仔猪,随机分成4组,每组4个重复,每个重复15头仔猪。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加0.02%、0.03%和0.04%RECC的饲粮。试验期28 d。结果显示:1)与对照组相比,饲粮添加0.02%和0.03%RECC显著提高断奶仔猪平均日增重和平均日采食量(P0.05)、显著降低料重比(P0.05),各RECC组断奶仔猪腹泻率均显著降低(P0.05)。2)饲粮添加0.02%和0.03%RECC显著提高断奶仔猪血清生长激素和免疫球蛋白G含量(P0.05)。3)饲粮添加0.02%和0.03%RECC显著提高断奶仔猪对干物质、粗蛋白质和粗脂肪的消化率(P0.05),饲粮添加0.02%RECC显著提高仔猪对Ca和P的消化率(P0.05)。4)饲粮添加RECC对仔猪粪中大肠杆菌、双歧杆菌和乳酸杆菌数影响均不显著(P0.05),但有降低大肠杆菌数的趋势。综上所述,饲粮中添加RECC可以通过提高断奶仔猪体内的激素含量、调节微生物平衡,进而改善仔猪的生长、免疫等功能,且RECC在断奶仔猪中较为适宜的添加量为0.02%。     

银杏叶提取物对断奶仔猪养分消化率、消化酶活性及肠道吸收能力的影响

本试验旨在研究银杏叶提取物(EGB)对断奶仔猪养分消化率、消化酶活性及肠道吸收能力的影响。将80头25日龄的杜×长×大三元杂交断奶仔猪随机分为2组,每组4个重复,每个重复10头。对照组饲喂基础日粮,试验组在基础日粮中添加0.2%EGB。试验期为28 d。测定断奶仔猪养分消化率、消化酶活性和血清D-木糖含量。结果表明:与对照组相比,日粮中添加0.2%EGB可显著提高断奶仔猪对粗蛋白和粗脂肪的消化率(P<0.05),显著提高仔猪十二指肠、空肠和回肠胃蛋白酶、胰蛋白酶、脂肪酶、淀粉酶活性(P<0.05),显著提高仔猪血清D-木糖含量(P<0.05)。本试验表明,日粮中添加0.2%EGB可提高断奶仔猪对营养物质的消化吸收能力。     

酵母水解物对断奶仔猪生长性能、血清免疫和抗氧化能力及粪便菌群的影响

本试验旨在研究酵母水解物对断奶仔猪生长性能、血清免疫和抗氧化能力及粪便菌群的影响。试验选取28头平均体重为(8.02±0.39) kg、健康的(28±1)日龄"杜×长×大"断奶仔猪,随机分为对照组(基础饲粮)和酵母水解物组(酵母水解物等量替代基础饲粮中0.5%的去皮豆粕),每组14个重复,每个重复1头仔猪。试验期28 d。试验结束时,各组选取10头接近平均体重的仔猪,空腹12 h后于试验第29天早上前腔静脉采血,分离血清,-20℃保存待测;同时,采集直肠粪便样,-80℃保存待测。结果表明,与对照组相比:1)饲粮添加酵母水解物可极显著提高断奶仔猪平均日增重和平均日采食量(P0.01),极显著降低腹泻率(P0.01),且有降低料重比的趋势(P=0.07); 2)饲粮添加酵母水解物显著降低断奶仔猪血清低密度脂蛋白胆固醇和丙二醛含量(P0.05),有降低血清甘油三酯含量的趋势(P=0.07); 3)饲粮添加酵母水解物显著提高断奶仔猪血清总抗氧化能力和谷胱甘肽过氧化物酶活性(P0.05),显著提高血清白蛋白、补体3和补体4含量(P0.05); 4)饲粮添加酵母水解物显著增加断奶仔猪直肠粪便芽孢杆菌数量(P0.05),使大肠杆菌数量降低6.53%(P0.05)。综上所述,饲粮添加0.5%酵母水解物可改善断奶仔猪生长性能,增强机体先天性免疫和血清抗氧化能力,提高直肠粪便芽孢杆菌数量。     

菊粉对断奶仔猪血液生化指标的影响

试验主要探讨菊粉对断奶仔猪血液生化指标的影响.试验选用21日龄、体重相近、健康的杜×长×大三元杂交断奶仔猪72头,随机分为3个处理,每个处理3个重复,每个重复8头.处理Ⅰ组日粮为玉米一豆粕型基础日粮,处理Ⅱ为基础日粮+2%菊粉.处理Ⅲ为基础日粮+0.07%抗生素,试验期为21 d.试验结果表明:添加2%菊粉能改善断奶仔猪的血清生化指标.(1)抗生素组和菊粉组血清尿素氮(BUN)含量低于对照组(P>0.05),对于血糖(GLU)含量也无显著影响(P>0.05).(2)添加菊粉能有效提高血清中碱性磷酸酶(ALP)的活性(P>0.05),显著提高IL-2和IGF-1含量(P<0.05).(3)抗生素组和菊粉组均能有效提高血清中GH、FT<,3>、FT<,4>的含量(P<0.01或P<0.05).(4)与对照组相比,菊粉组的超氧化物歧化酶(SOD)、过氧化氢酸(CAT)和NO水平均有所提高的趋势,但差异不显著(P>0.05);仅抗生素组的CAT较对照组极显著提高(P<0.01),而抗生素组和菊粉组的丙二醛(MDA)显著低于对照组(P<0.05).从整体来看,菊粉能很好改善断奶仔猪体内的血液生化指标,但抗生素组效果最佳.     

Dietary supplementation with multienzyme preparations improves nutrient utilization and growth performance in weaned pigs

Two experiments with young pigs (25 d of age) were conducted to investigate the effect of multienzyme preparations on nutrient digestibility, growth performance, and P utilization and excretion. In Exp. 1, 24 pigs (six pigs per treatment) were used in a 28-d performance and digestibility trial using four diets: control (no enzyme) and control supplemented with enzyme preparation A, B, or C. The control diet was formulated to meet 95% of NRC (1998) nutrient specifications (except for available P, which was at 44% NRC) and composed of corn, wheat, wheat by-products, barley, soybean meal, canola meal, and peas. All three enzyme preparations contained xylanase, glucanase, amylase, protease, invertase, and phytase activities and differed in the type of plant cell wall-degrading activities; Enzyme A contained cellulase, galactanase, and mannanase; Enzyme B contained cellulase and pectinase; and Enzyme C contained cellulase, galactanase, mannanase, and pectinase. Pigs fed enzyme-supplemented diets had higher ADG (P = 0.02) and G:F (P = 0.01) than those fed the control diet. On average, and when compared with control diet, enzyme supplementation improved (P = 0.001 to 0.04) ileal digestibility of DM (60 vs. 66%), GE (62.8 vs. 70.4%), CP (62 vs. 72%), starch (86.7 vs. 94.2%), nonstarch polysaccharides (NSP; 10.1 vs. 17.6%), and phytate (59 vs. 70%). Compared with the control, total-tract digestibility of nutrients was increased (P = 0.001 to 0.01) owing to enzyme supplementation, with Enzyme C showing the highest improvement in DM, GE, CP, starch, NSP, phytate, and P utilization. Pigs fed enzyme-supplemented diets had decreased (P = 0.04) fecal P excretion. The benefit from improved nutrient utilization with enzyme supplementation was further substantiated in a 38-d growth performance study with 48 pigs. The control and Enzyme C-supplemented diets (same as Exp. 1) were assigned to six replicate pens (four pigs per pen). The study was conducted in three phases (Phase 1 = d 0 to 7; Phase 2 = d 7 to 21; Phase 3 = d 21 to 38). Individual BW and pen feed disappearance were monitored. Average daily gain and G:F were 231 and 257 g (P = 0.01), and 0.56 and 0.63 (P = 0.001) for the control and enzyme-supplemented diets, respectively. It is evident from this study that the use of enzyme preparations may allow for cost-effective and environmentally friendly formulation of young pig diets.     

Supplementation of different fat sources affects growth performance and carcass composition of finishing pigs

Background: There are various fat sources with different energy values and fatty acid compositions that may affect growth performance and carcass composition of grow-finishing pigs. A higher net energy was recently reported in choice white grease compared with soybean oil. Therefore, two experiments were conducted to determine whether practical responses confirm that difference between choice white grease and soybean oil, and to extend the observations to other fat sources.Results: In Exp. 1, pigs fed fats had lower(P 0.05) average daily feed intake in phase II and overall period,greater(P 0.05) gain:feed in phase I, phase II, and overall period than pigs fed the control diet. Pigs fed fats tended(P = 0.057) to have thicker backfat depth at the last rib than those fed control. Pigs fed 6% fats had greater(P 0.01) gain:feed in phase II and overall period than pigs fed 3% fats. During phase I, pigs fed choice white grease grew faster(P 0.05) than pigs fed soybean oil. In Exp. 2, pigs fed dietary fats(soybean oil, choice white grease, animal-vegetable blend, palm oil, or tallow) had greater(P 0.01) gain:feed in each phase and overall period, greater(P 0.01) average daily gain in phase I, but lower(P 0.01) average daily feed intake in phase II an overall than pigs fed the control diets. The choice white grease also increased(P 0.05) average daily gain during phase I compared with soybean oil. Pigs fed palm oil had thicker(P 0.05) backfat depth at the 10 thrib than those fed soybean oil, animal-vegetable blend, or tallow.Conclusions: Inclusion of 6% dietary fat improved feed efficiency of finishing pigs, while different fats produced different practical results that may be consistent with their different energy values. Results from the early stage indicate that dietary fats with relatively more saturated fatty acids may provide greater energy than those with relatively more unsaturated fatty acids for growing pigs.     

Effects of rancidity and free fatty acids in choice white grease on growth performance and nutrient digestibility in weanling pigs

Two experiments were conducted to determine the effects of rancidity and FFA in choice white grease (CWG) on growth performance and nutrient digestibility in nursery pigs. In Exp. 1,150 crossbred pigs (average initial BW of 6.8 kg and average initial age of 21 d) were used. Treatments (as-fed basis) were a corn-soybean meal-based control with no added fat, 6% CWG, and 6% CWG heated at 80 degrees C, with oxygen gas bubbled through it at 849 mL/min for 5, 7, 9, or 11 d. Peroxide value for the CWG increased as oxidative exposure was increased from 0 to 7 d (i.e., peroxide values of 1, 40, and 105 mEq/kg for d 0, 5, and 7, respectively), but decreased to 1 mEq/kg as the hydroperoxides decomposed after 9 and 11 d of oxidation. Pigs fed the control diet (no added fat) had the same (P = 0.91) overall ADG (d 0 to 35) but lower G:F (P < 0.04) than pigs fed diets with added fat. As for the effects of fat quality, ADG (linear effect, P < 0.01) and ADFI (linear effect, P < 0.001) decreased as the fat was made more rancid. However, there were no changes in digestibility of fatty acids as the rancidity of the fat was increased (P = 0.16), suggesting that the negative effects of rancidity were from decreased food intake and not decreased nutrient utilization. In Exp. 2, 125 crossbred pigs (average initial BW of 6.2 kg and average initial age of 21 d) were used to determine the effects of FFA in CWG on the growth performance and nutrient digestibility in nursery pigs. Treatments (as-fed basis) were a corn-soybean meal-based control with no added fat, 6% CWG, and 6% CWG that had been treated with 872, 1,752 or 2,248 lipase units/g of fat. The FFA concentrations in the CWG were increased from 2% with no lipase added to 18, 35, and 53% as lipase additions were increased. Pigs fed the control diet (no added fat) had the same (P = 0.30) overall ADG (d 0 to 33) but lower G:F (P < 0.01) than pigs fed diets with added fat. There were no effects of FFA concentration on ADG (P = 0.18), and ADFI increased (linear effect, P < 0.04) as FFA concentration in the CWG increased. Fatty acid digestibility was not affected (P = 0.17) by FFA in the diet. In conclusion, our data suggest that as fat is oxidized (especially to peroxide values greater than 40 mEq/kg), ADG and ADFI in nursery pigs will decrease; however, FFA concentrations of at least 53% do not adversely affect utilization of CWG in nursery pigs.     

The effects of thermal environment and spray-dried plasma on the acute-phase response of pigs challenged with lipopolysaccharide

Forty barrows (TR4 x C22) were weaned at 17 d of age (BW = 6.27 +/- 0.30 kg), housed (two pigs/pen) in a thermal-neutral environment (TN; constant 26.7 degrees C), and fed diets with or without 7% (as-fed basis) spray-dried plasma (SDP). On d 7, one pig/ pen was moved into a cold environment (CE; constant 15.6 degrees C). Pigs were fitted with jugular catheters on d 11. On d 12, 16 pigs per environment (eight pigs per dietary treatment) were challenged i.v. with 75 microg of lipopolysaccharide (LPS)/kg of BW. Blood samples were collected over a 4.5-h period. Pigs were then killed and tissue samples were harvested for messenger RNA (mRNA) analysis. From d 0 to 7, pigs fed SDP diets had a lower gain:feed ratio (G/F) than pigs fed no SDP (533 +/- 14 vs. 585 +/- 17 g/kg; P < 0.03). Pigs housed in the CE consumed more feed and had a lower G/F than pigs housed in TN from d 7 to 11 (P < 0.001). There were no environment x diet interactions from d 7 to 11 (P > 0.78). Baseline concentrations of serum ACTH and cortisol were lower in the TN pigs than in the CE pigs (P < 0.001). Pigs fed diets without SDP had lower serum cortisol concentrations over the 4.5-h period than pigs fed SDP (time x diet, P < 0.001). Serum concentrations of tumor necrosis factor-alpha (TNF-alpha) were highest for pigs consuming SDP in the CE, whereas there were no differences among the other treatments (time x diet x environment, P < 0.02). Pigs housed in the CE had higher serum interleukin-1beta (IL-1beta) (P < 0.001) and interleukin-6 (IL-6; P < 0.001) than TN pigs. Pigs fed SDP also had slightly higher serum IL-1beta concentrations (P < 0.10) and higher (P < 0.001) IL-6 concentrations than pigs fed no SDP. Pigs fed SDP had 9% lower liver and 13% lower thymus mRNA expression of tumor necrosis factor-alpha (TNF-alpha) than pigs that consumed no SDP (P < 0.06). Liver IL-1beta, IL-6, and LPS-binding protein mRNA were higher in the CE than in the TN (P < 0.03, P < 0.001, and P < 0.05; respectively). In addition, spleen TNF-alpha (P < 0.03) and IL-6 (P < 0.01) mRNA levels were higher in the CE than in the TN. Pigs consuming SDP and challenged with LPS responded with elevated serum concentrations of cortisol and cytokines compared with pigs fed diets with no SDP. Housing pigs in a CE increased the baseline concentrations of ACTH and cortisol, and when coupled with an LPS challenge, resulted in elevated serum and tissue mRNA levels of cytokines. Cold stress and feeding SDP during a LPS challenge may result in increased stress and immune responses in young pigs.     

30～60kg生长猪磷需要量研究

本试验旨在研究饲粮磷水平对30 ～60kg生长猪生长性能、血清生化指标及胫骨性能的影响,探讨饲粮中磷的适宜需要量.试验采用单因子完全随机设计,将30头体重( 32.12±0.49) kg的“杜×长×大”生长猪随机分为5组,每组6个重复,每个重复1头猪,各组分别饲喂磷水平为0.38％(对照组)、0.43％、0.48％、0.53％、0.58％的玉米-豆粕型试验饲粮.预试期7d,正试期28 d.结果表明:1)与对照组相比,0.53％磷水平组平均日增重、平均日采食量极显著提高(P＜0.01),料重比极显著降低(P＜0.01);2)各试验组血清磷含量均极显著高于对照组(P＜0.01),0.53％磷水平组血清钙含量显著低于对照组(P＜0.05),各组血清胰岛素样生长因子-Ⅰ含量差异不显著(P＞0.05);3)随饲粮磷水平的提高,胫骨长度及胫骨钙、磷含量均呈现先升高再降低的趋势,当饲粮磷水平为0.53％时,各指标达到最大值,但差异不显著(P＞0.05);0.53％磷水平组胫骨脱脂烘干重显著高于对照组(P＜0.05),其他各组之间差异不显著(P＞0.05).综上所述,在本试验条件下,30 ～ 60 kg生长猪饲粮磷的适宜添加水平为0.53％.     

小麦基础饲粮中添加木聚糖酶对生长猪生长性能、血清生化指标及肠道微生物菌群的影响

本试验旨在研究在小麦基础饲粮中添加木聚糖酶对生长猪生长性能、营养物质表观消化率、血清生化指标及肠道微生物菌群的影响,探讨适宜的木聚糖酶添加水平。选择80头健康、平均体重40 kg的"杜×长×大"生长猪,随机分为5个处理,每个处理4个重复,每个重复4头猪。正对照组饲喂玉米-豆粕型基础饲粮,负对照组饲喂小麦-豆粕型基础饲粮,木聚糖酶组分别饲喂在负对照基础饲粮上添加500、1 000和2 000 U/kg木聚糖酶的试验饲粮。试验期28 d。结果表明:1)小麦基础饲粮中添加木聚糖酶可极显著提高生长猪平均日增重(P<0.01),显著或极显著提高平均日采食量和营养物质表观消化率(P<0.05或P<0.01),其中2 000 U/kg木聚糖酶组效果最好,平均日增重和平均日采食量分别提高了26.0%和16.5%(P<0.01);2)小麦基础饲粮中添加木聚糖酶显著或极显著提高了生长猪血清葡萄糖、三碘甲腺原氨酸、四碘甲腺原氨酸和D-木糖含量(P<0.05或P<0.01),极显著降低血清尿素氮含量(P<0.01);3)饲粮组成和木聚糖酶可显著影响猪肠道微生物菌群,添加木聚糖酶可维持动物肠道微生物菌群的平衡,2 000 U/kg木聚糖酶组肠道菌群结构和玉米-豆粕饲粮饲喂条件下接近。由此可见,添加2 000 U/kg的木聚糖酶可显著改善饲喂小麦基础饲粮生长猪的生长性能和营养物质表观消化率,维持肠道微生物菌群的平衡。在木聚糖含量为11.2%的生长猪小麦基础饲粮中,木聚糖酶的适宜添加水平为2 000 U/kg。     

Ractopamine对大约克猪蛋白质和脂肪代谢的影响

用添加２０ｍｇ／ｋｇＲａｃｔｏｐａｍｉｎｅ的饲粮饲喂纯种大约克肥育猪，发现半腱肌ＤＮＡ含量降低１４％（Ｐ＜０．０１），ＲＮＡ含量升高７．７％（Ｐ＜０．０１），背最长肌ＤＮＡ含量下降７％（Ｐ＜０．０１），ＲＮＡ上升５．５％（Ｐ＜０．０１），且两种肌肉中的ＲＮＡ／ＤＮＡ均呈升高趋势；背最长肌中酪氨酸、苏氨酸和蛋氨酸含量分别降低２５％（Ｐ＜０．０５）、９％（Ｐ＜０．０１）和１７％（Ｐ＜０．０５），而甘氨酸和丙氨酸含量分别上升１５％（Ｐ＜０．０５）和８％（Ｐ＜０．０５），肝组织中天冬氨酸和异亮氨酸分别提高１１．６％（Ｐ＜０．０１）和１２％（Ｐ＜０．０１）；此外背最长肌肌原纤维的降解系数（ＭＦＩ）明显降低，血清尿素氮下降１６．６％（Ｐ＜０．０５）。同时还发现Ｒａｃｔｏｐａｍｉｎｅ使皮下脂肪中异柠檬酸脱氢酶活力降低２７％（Ｐ＜０．０１），血清脂肪酶活力升高１２．２％（Ｐ＜０．０５），血清胆固醇降低２３．５％（Ｐ＜０．０５）。上述结果显示：Ｒａｃｔｏｐａｍｉｎｅ可促进体内蛋白质的合成和脂肪的分解，而抑制蛋白质的降解和脂肪的合成     

壳聚糖对仔猪生长性能及血清中类胰岛素生长因子-Ⅰ和生长激素水平的影响

本文旨在研究日粮中添加不同剂量壳聚糖对仔猪生产性能及血清中类胰岛素生长因子-I(IGF-I)和生长激素(GH)水平的影响。试验选择60日龄大白×长白×VI系杂交仔猪96头,随机分为4个日粮处理组,每个处理3个重复,每个重复8头,进行为期21 d的饲养试验。4种日粮分别是在基础日粮中添加0、0 .01 %、0 .05 %、0.1 %的壳聚糖配制而成。结果表明,壳聚糖对仔猪生长性能的影响呈二次剂量依赖关系,添加0 .01 %~0 .05 %壳聚糖能够提高仔猪平均日增重、平均日采食量及增重耗料比,并可提高仔猪血清中IGF-Ι和GH含量。而添加更高水平时生长性能却有下降趋势。因此,在本试验条件下初步得出,0 .01 %~0 .05 %为壳聚糖在仔猪日粮中的适宜添加量。     

Utilization of spray-dried blood cells and crystalline isoleucine in nursery pig diets

Three experiments were conducted to evaluate spray-dried blood cells (SDBC) and crystalline isoleucine in nursery pigs. In Exp. 1, 120 pigs were used to evaluate 0, 2, 4, and 6% SDBC (as-fed basis) in a sorghum-based diet. There were six replicates of each treatment and five pigs per pen, with treatments imposed at an initial BW of 9.3 kg and continued for 16 d. Increasing SDBC from 0 to 4% had no effect on ADG, ADFI, and G:F. Pigs fed the 6% SDBC diet had decreased ADG (P < 0.01) and G:F (P = 0.06) compared with pigs fed diets containing 0, 2, or 4% SDBC. In Exp. 2, 936 pigs were used to test diets containing 2.5 or 5% SDBC (as-fed basis) vs. two control diets. There were six replicates of each treatment at industry (20 pigs per pen) and university (six pigs per pen) locations. Treatments were imposed at an initial BW of 5.9 and 8.1 kg at the industry and the university locations, respectively, and continued for 16 d. Little effect on pig performance was noted by supplementing 2.5% SDBC, with or without crystalline Ile, in nursery diets. Pigs fed the 5% SDBC diet without crystalline Ile had decreased ADG (P < 0.01), ADFI (P < or = 0.10), and G:F (P < 0.05) compared with pigs fed the control diets. Supplementation of Ile restored ADG, ADFI, and G:F to levels that were not different from that of pigs fed the control diets. In Exp. 3, 1,050 pigs were used to test diets containing 5, 7.5, or 9% SDBC (as-fed basis) vs. a control diet. There were six replicates of each treatment at the industry (20 pigs per pen) location and five replicates at the university (six pigs per pen) locations. Treatments were imposed at an initial BW of 6.3 and 7.0 kg at the industry and university locations, respectively, and continued for 16 d. Supplementation of 5% SDBC without crystalline Ile decreased ADG and G:F (P < 0.01) compared with pigs fed the control diet, but addition of Ile increased ADG (P < 0.01) to a level not different from that of pigs fed the control diet. The decreased ADG, ADFI, and G:F noted in pigs fed the 7.5% SDBC diet was improved by addition of Ile (P < 0.01), such that ADG and ADFI did not differ from those of pigs fed the control diet. Pigs fed diets containing 9.5% SDBC exhibited decreased ADG, ADFI, and G:F (P < 0.01), all of which were improved by Ile addition (P < 0.01); however, ADG (P < 0.05) and G:F (P = 0.09) remained lower than for pigs fed the control diet. These data indicate that SDBC can be supplemented at relatively high levels to nursery diets, provided that Ile requirements are met.     

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.