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、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5组,每组设4个重复。对照组饲喂基础日粮,试验组在基础日粮的基础上添加0.2%核苷酸。饲养期21d。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7d胰腺率,比对照组提高35.48%(P<0.05),并有提高仔猪断奶后第14d肝脏指数、脾脏指数的趋势,但差异不显著(P>0.05);日粮中添加核苷酸可以显著提高仔猪断奶后第21d血清总蛋白和血清白蛋白,分别比对照组提高32.64%(P<0.01)和57.76%(P<0.01);并可显著提高仔猪断奶后第14d空肠黏膜蔗糖酶活性,比对照组提高74.59%(P<0.05)。     

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。     

中草药饲料添加剂对断奶仔猪生长性能和肠道消化酶活性的影响

试验研究日粮中添加不同水平的中草药饲料添加剂对断奶仔猪生长性能和肠道消化酶活性的影响。选用54头21日龄断奶、体重(6.25±0.85)kg的杜×大×长仔猪,随机分成3组,每组3个重复,每个重复6头仔猪。试验日粮分别为:基础日粮;基础日粮+0.3%中草药饲料添加剂;基础日粮+0.4%中草药饲料添加剂。本试验证明,仔猪断奶后第1周在日粮中添加0.3%、0.4%的中草药饲料添加剂可提高断奶仔猪日增重、降低料肉比,显著降低断奶后仔猪腹泻率。仔猪断奶后前2周,添加0.3%、0.4%中草药饲料添加剂显著提高仔猪断奶后第7 d空肠后段总蛋白酶活性、空肠后段淀粉酶活性和空肠后段脂肪酶活性;显著提高仔猪断奶后第14 d空肠后段脂肪酶活性;且整体来看0.4%的添加效果优于0.3%的添加水平所体现的效果。     

丁酸钠对断奶仔猪生长性能和肠道消化酶活性的影响

本试验研究日粮中添加不同浓度的丁酸钠以及断奶天数对断奶仔猪生长性能和肠道消化酶活性的影响.选用96头21日龄断奶、体重(6.00±0.05)kg的杜×长×大仔猪,随机分成对照组、试验组1和试验组2,每组4个重复,每个重复8头仔猪.丁酸钠的添加浓度分别为0、1和2 g/kg.在断奶后第3天、第7天和第14天从各个重复中分别取1头仔猪屠宰取样.结果表明,在仔猪断奶后第3天、第7天和第14天,试验组1的平均日增重比对照组提高了5.0%(P>0.05)、13.4%(P<0.05)和2.3%(P>0.05).仔猪断奶后第1～14天的日平均酶活:试验组1和试验组2的空肠前段、空肠后段和回肠总蛋白酶活性均高于对照组(P>0.05);试验组1和试验组2的十二指肠淀粉酶活性分别比对照组高28.5%(P>0.05)和6.4%(P>0.05);空肠前段淀粉酶活性分别比对照组高5.9%(P>0.05)和10.5%(P>0.05);回肠淀粉酶活性分别比对照组高21.5%(P>0.05)和22.1%(P>0.05).丁酸钠浓度影响断奶仔猪十二指肠和空肠前段的脂肪酶活性(P<0.05).断奶天数对十二指肠和空肠前段淀粉酶,以及各段肠道脂肪酶活性有显著影响(P<0.05),对空肠后段总蛋白酶活性有极显著影响(P=0.001).结果提示,日粮中添加1 g/kg的丁酸钠可以提高断奶仔猪生长性能以及肠道消化酶活性;断奶天数显著影响断奶仔猪肠道脂肪酶活性(P<0.05).     

饲粮添加三丁酸甘油酯和核苷酸对断奶仔猪生长性能、血清生化指标和肠组织形态的影响

本试验旨在研究饲粮添加三丁酸甘油酯和核苷酸对仔猪生长性能、血清生化指标和肠组织形态的影响。选择21日龄、体重为8.4 kg左右的健康杜洛克×长白×大约克(DLY)三元断奶仔猪160头,随机分为2组,每组10个重复,每个重复8头。对照组饲喂基础饲粮,试验组饲喂在基础饲粮中添加0.20%三丁酸甘油酯和0.15%核苷酸的试验饲粮,试验期为38 d。结果表明:1)与对照组相比,饲粮添加三丁酸甘油酯和核苷酸显著提高了断奶仔猪的平均日增重(P0.05),极显著降低了腹泻率(P0.01),显著提高了血清免疫球蛋白A、免疫球蛋白G、免疫球蛋白M以及球蛋白含量(P0.05),显著降低了血清二胺氧化酶活性和葡萄糖含量(P0.05);2)与对照组相比,饲粮添加三丁酸甘油酯和核苷酸显著提高了断奶仔猪十二指肠和空肠绒毛高度和绒毛高度/隐窝深度值(P0.05),显著提高了空肠内容物胰蛋白酶和麦芽糖酶活性(P0.05)。由此可见,饲粮添加0.20%三丁酸甘油酯和0.15%核苷酸可促进仔猪生长,提高机体免疫力,降低断奶应激对肠道的损伤,提高消化酶活性,改善仔猪的消化吸收功能。     

谷氨酰胺对新生仔猪生长性能、血清激素水平及小肠黏膜酶活性的影响

本试验旨在研究谷氨酰胺(Gln)对新生仔猪生长性能、血清激素水平和小肠黏膜中相关酶活性的影响.试验选用4日龄新生仔猪36头,分成3组,每组4个重复,每个重复3头(2公1母),各组日粮中分别添加0(对照组)、0.5%和1.0%谷氨酰胺.试验期18 d.结果表明:与对照组相比,日粮中添加1.0%谷氨酰胺显著提高了仔猪4～14日龄平均日采食量(P<0.05);日粮中添加0.5%谷氨酰胺显著提高了仔猪14日龄血清胃泌素含量(P<0.05);添加1.0%谷氨酰胺也显著提高了仔猪21日龄血清胃泌素含量(P<0.05);仔猪21日龄时,添加0.5%和1.0%谷氨酰胺显著提高了空肠黏膜中鸟氨酸脱羧酶(ODC)、Ca2+,Mg2+-ATP酶和Na+,K+-ATP酶的活性(P<0.05);添加1.0%谷氨酰胺显著降低了空肠黏膜中谷氨酰胺合成酶(GS)和鸟氨酸转氨酶(OAT)的活性(P<0.05).日粮中添加1.0%谷氨酰胺显著提高了仔猪14日龄空肠黏膜蔗糖酶、麦芽糖酶和乳糖酶活性(P<0.05).综上所述,日粮中添加1.0%谷氨酰胺提高了人工饲养新生仔猪14日龄肠道消化能力,改善了21日龄空肠黏膜中与谷氨酰胺代谢相关的酶活性.     

维生素D_3对断奶仔猪生长性能、抗氧化性能和免疫功能的影响

本试验旨在研究日粮高水平维生素D_3对断奶仔猪生长性能、血清抗氧化、血清和肠道免疫性能的影响。试验共选择25日龄断奶仔猪120头,随机分为2组,每组3个重复,每个重复20头猪。对照组饲喂基础日粮,日粮维生素D_3含量为250 IU/kg,试验组在基础日粮中添加维生素D_3,使维生素D_3含量为基础日粮的10倍(2500 IU/kg),试验从断奶后开展21 d。结果 :试验组较对照组显著降低了12~21 d断奶仔猪的腹泻指数(P0.05);对照组断奶仔猪1~7 d日增重表现为负增长,试验组显著提高了断奶仔猪生长早期的日增重(P0.05);与对照组相比,试验组显著提高了15~21 d断奶仔猪的饲料利用率(P0.05)。试验组较对照组显著降低了断奶仔猪第7天血清尿素氮的含量(P0.05);与对照组相比,试验组显著降低了断奶仔猪第14和21天血清丙二醛含量(P0.05),显著提高了断奶仔猪第7天血清超氧化物歧化酶含量和21 d血清谷胱甘肽过氧化物酶含量(P0.05)。试验组较对照组提高了断奶仔猪第7天绒毛高度,显著提高了28.77%(P0.05)。试验组较对照组显著提高了断奶仔猪14 d血清Ig M的含量(P0.05);试验组显著提高了断奶仔猪14 d回肠内容物Ig M、Ig G和Ig A的含量(P0.05)。结论 :日粮适宜水平维生素D_3可以改善断奶仔猪的料重比,提高断奶仔猪生长早期和后期的抗氧化和免疫性能。     

饲粮中添加腐植酸钠和核苷酸对断奶仔猪生长性能的影响

试验旨在研究饲粮中添加腐殖酸钠和核苷酸对仔猪生长性能、血清生化指标和肠组织的影响。选取21日龄DLY断奶仔猪160头,随机分为2组,对照组饲喂基础饲粮,试验组饲喂添加3.0kg/t腐植酸钠和1.5kg/t核苷酸的试验饲粮,试验期38d。结果表明:(1)饲粮中添加腐殖酸钠和核苷酸显著提高了仔猪的日增重、料重比(P0.05),腹泻率显著降低55.85%(P0.05),血清中二胺氧化酶和磷酸肌酸激酶活性分别显著降低了31.91%和32.16%(P0.05);(2)饲粮中添加腐殖酸钠和核苷酸提高了十二指肠、空肠和回肠绒毛高度,增加5.49%~7.85%(P0.05),V/C比值增加17.03%~21.32%(P0.05),肠壁厚度和黏膜厚度分别增加8.52%~21.76%(P0.05)和5.14%~11.33%(P0.05),空肠食糜中蔗糖酶活性显著提高了50.91%(P0.05);(3)饲粮中添加腐植酸钠和核苷酸可使仔猪每头增益34.34元。由此可见,饲粮中添加3.0kg/t腐殖酸钠和1.5kg/t核苷酸可促进仔猪生长,降低腹泻率,降低断奶应激对肠道的损伤,增强肠道屏障功能,提高消化酶活性,提高仔猪的消化吸收功能。     

丙氨酰-谷氨酰胺对断奶仔猪小肠黏膜固有层免疫球蛋白A浆细胞数量、分泌型免疫球蛋白A及黏膜中白细胞介素含量的影响

本试验旨在研究丙氨酰-谷氨酰胺(Ala-Gln)对断奶仔猪小肠黏膜固有层免疫球蛋白A(Ig A)浆细胞数量、分泌型免疫球蛋白A(SIg A)及黏膜中白细胞介素(IL)含量的影响。试验选用(21±2)日龄断奶、初始体重(6.7±0.9)kg的长白×大白去势仔猪100头,按完全随机区组法分为4组,每组5个重复,每重复5头仔猪。对照组饲喂基础饲粮,试验组分别饲喂基础饲粮中添加0.15%、0.30%和0.45%Ala-Gln的试验饲粮。试验期21 d。结果显示:1)与对照组相比,饲粮中添加0.15%~0.45%Ala-Gln均显著提高仔猪断奶后第7、14、21天十二指肠以及空肠黏膜固有层Ig A浆细胞数量(P0.05),特别是0.30%Ala-Gln组仔猪在断奶第14天空肠Ig A浆细胞数比对照组增加22.6%(P0.05);在回肠中,0.30%Ala-Gln主显著提高断奶后第7、14天仔猪Ig A浆细胞数(P0.05)。2)断奶仔猪空肠黏膜SIg A含量随着Ala-Gln添加量呈二次曲线增长规律。在断奶后第7天,0.30%Ala-Gln组仔猪SIg A含量与对照组相比极显著提高了70.4%(P0.01);在断奶后第14、21天,0.15%、0.30%Ala-Gln与对照组相比显著提高了SIg A含量(P0.05)。3)与对照组相比,饲粮中添加0.15%、0.30%Ala-Gln可显著提高仔猪早期断奶后第7天黏膜IL-2、IL-5含量,分别显著提高断奶后第14天IL-5、IL-2含量(P0.05),其他添加水平无显著影响(P0.05);随着饲粮中Ala-Gln添加量的增加,各组IL-6、IL-10的含量呈线性增长趋势,且显著高于对照组(P0.05)。综上所述,饲粮中添加Ala-Gln可提高肠黏膜固有层Ig A浆细胞数量、黏膜SIg A分泌量及IL含量,提高断奶仔猪肠道黏膜细胞免疫。     

断奶应激对奶水牛犊牛血液生理生化指标和免疫功能的影响

为研究断奶应激对奶水牛犊牛的影响,选用5头健康犊牛,分别于断奶前1 d、断奶后1、14和21 d进行采血,测定犊牛的血常规、血清生化指标和免疫指标。结果显示,奶水牛犊牛的白细胞数、淋巴细胞数、红细胞数、单核细胞数、红细胞压积、天冬氨酸转氨酶活性、血糖含量、皮质醇含量、免疫球蛋白G含量在断奶前后无显著变化（P > 0.05）;中性粒细胞数在断奶后21 d显著低于断奶前1 d（P < 0.05）;血清乳酸脱氢酶、丙氨酸转氨酶活性在断奶后显著高于断奶前（P < 0.05）;血清尿素氮含量在断奶后21 d显著高于断奶前1 d（P < 0.05）;血红蛋白含量在断奶21 d显著低于断奶前1 d（P < 0.05）。结果表明断奶应激不仅影响了奶水牛犊牛的生理机能,而且降低了其免疫力和抵抗力。     

Effect of Weaning Stress on Blood Physiology and Biochemistry Indexes and Immune Function in Dairy Buffalo Calves

To study the effect of weaning stress on dairy buffalo calves,5 healthy calves were chosen and weaned,and the blood samples were collected at 1 day before weaning,and 1,14 and 21 days after weaning to analysis blood physiology and biochemistry indexes and immune function.The results showed that the count of white blood cell,lymphocyte,erythrocyte,monocytes and hematocrit,aspartate aminotransferase activity,blood glucose,cortisol and immunoglobulin G contents of dairy buffalo calves were no significant difference between before and after weaning treatments (P > 0.05).The count of neutrophils at 21 d after weaning were significantly lower than that of 1 d before weaning of dairy buffalo calves (P < 0.05).However,lactate dehydrogenase and alanine aminotransferase activity in weaned treatments were significantly higher than those of animals in the treatment before weaning (P < 0.05).The serum urea nitrogen of dairy buffalo calves at 21 d after weaning was significantly higher than that of 1 d before weaning (P < 0.05) and hemoglobin content at 21 d after weaning was significantly lower than that at 1 day before weaning (P < 0.05).It indicated that the physiological and immunity function of dairy buffalo calves were challenged under weaning stress.     

Effects of altrenogest treatments before and after weaning on follicular development, farrowing rate, and litter size in sows

In a previous study, we showed that follicle size at weaning affects the response of a sow to a short-term altrenogest treatment after weaning. In this study, an attempt was made to prevent the growth of follicles into larger size categories before weaning by using different altrenogest treatments before weaning to improve reproductive performance after postweaning altrenogest treatments. Sows (87 primiparous and 130 multiparous) were assigned to the following treatments: control (no altrenogest treatment; n=59), RU0-20 (20 mg of altrenogest from d -1 to 6; weaning=d 0; n=53), RU40-20 (40 mg of altrenogest from d -3 to 0 and 20 mg of altrenogest from d 1 to 6; n=53), and RU20-20 (20 mg of altrenogest from d -3 to 6; n=52). Follicle size was assessed daily with transabdominal ultrasound. Follicle sizes on d -3 (3.6 ± 0.7 mm) and at weaning (4.0 ± 0.7 mm) were similar for all treatments. Altrenogest-treated sows had larger follicles at the beginning of the follicular phase than did control sows [5.4 ± 0.1 and 3.8 ± 0.2 mm (least squares means), respectively; P < 0.0001] and on d 4 of the follicular phase [8.0 ± 0.1 and 6.7 ± 0.2 mm (least squares means), respectively; P < 0.0001]. Multiparous sows had larger follicles than did primiparous sows at the beginning of the follicular phase [5.3 ± 0.1 and 4.7 ± 0.1 mm (least squares means), respectively; P < 0.01] and on d 4 of the follicular phase [8.0 ± 0.1 and 7.0 ± 0.1 mm (least squares means), respectively; P < 0.0001]. Farrowing rate and litter size (born alive + dead) were not affected by treatment or parity. However, in primiparous sows, when mummies were included in litter size, altrenogest-treated sows had larger litters than did control sows (13.4 ± 0.5 and 11.9 ± 0.7 piglets, respectively; P=0.02). In primiparous control sows, backfat depth at weaning and litter size were positively related (slope of the regression line=0.82; P < 0.05), which was not the case in primiparous sows receiving altrenogest. In conclusion, the different altrenogest treatments before weaning did not prevent the growth of follicles before weaning and similarly affected subsequent follicle development and fertility. In primiparous sows, altrenogest treatment after weaning increased the number of fetuses during pregnancy, but positive effects seemed limited by uterine capacity. Altrenogest treatment after weaning improved litter size in primiparous sows with reduced backfat depth at weaning, which suggests a specific positive effect of a recovery period after weaning in sows with reduced BCS at weaning.     

Survival rate and development of fetuses during the first 30 days of gestation after folic acid addition to a swine diet

At weaning, 162 sows were assigned randomly to six treatments (27 in each treatment) according to a 2 X 3 factorial arrangement: two levels of supplementary folic acid (0 and 5 mg/kg of diet) and three treatments to stimulate ovulation (none, flushing and pregnant mare serum gonadotropin [PMSG] injection). All sows were mated twice within 7 d after weaning. Of the 162 animals originally selected, 123 sows were pregnant and used in this trial. The flushing treatment consisted of allowing sows ad libitum access to feed from the day after weaning through the 1st day of behavioral estrus, whereas control animals received 2.4 kg of feed daily. The hormonal treatment consisted of one i.m. injection of 1,250 IU of PMSG the day after weaning. The commercial-type diet used as the control was computed to contain .6 mg folates per kilogram. Folic acid supplementation elevated (P less than .001) serum folates between weaning and 30 d of gestation. Fetuses of sows fed the diet supplemented with folic acid had a higher (P less than .05) total protein concentration than fetuses of control sows, whereas RNA and DNA concentrations and protein:DNA ratio were not affected. The PMSG treatment elevated (P less than .05) ovulation rate, whereas the flushing or folic acid treatments had no effect on this trait. The addition of 5 mg/kg folic acid to the commercial-type diet improved (P less than .05) the survival rate of fetuses during early gestation and tended (P = .096) to increase the number of fetuses presumably living at 30 d of gestation when this treatment was associated with high ovulation rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary quillaja saponin and curcumin on the performance and immune status of weaned piglets

The objective of this study was to determine whether dietary quillaja saponin and curcumin (extract of turmeric) can modify piglet immune status and performance immediately after weaning. Piglets (n = 192) were weaned at 29 +/- 0.1 d and allocated to treatment (six replicates of eight pig per treatment) accounting for weight, litter, and gender, using a 2 x 2 factorial arrangement. Factors were diets with or without (as-fed basis) quillaja saponin (750 mg/kg during wk 1, 300 mg/kg during wk 2 to 3) and with or without dietary curcumin (200 mg/kg). Diets were fed ad libitum for 20 d after weaning. Feed intake was measured daily. Piglets were weighed at weaning, d 7, 14, and 20 after weaning. On each of d 6 and 20 after weaning, eight pigs per treatment were sacrificed for blood and tissue collection. Treatment had no effect on piglet growth. The ADFI and G:F were similar for all treatments between d 0 and 14 of the trial. Between d 15 and 20, ADFI and G:F were lower in quillaja-supplemented piglets (ADFI = 621 vs. 572 g/d; G:F = 0.75 vs. 0.85; P < 0.05). Serum immunoglobulin (Ig) G, IgA, interferon-gamma, and C-reactive protein (CRP) did not differ among treatments on d 6 after weaning. On d 20, IgG and CRP were greater (P < 0.05) in saponin-supplemented pigs (IgG = 17.5 vs. 11.4 mg/mL; CRP = 26.98 vs. 12.5 mg/mL). Small intestine villus and crypt measurements did not differ among treatments on either d 6 or 20. Saponin supplementation during the postweaning period seemed to potentiate an immune response in the weaned piglet but had a detrimental effect on the utilization of feed. Dietary curcumin had no influence on any measured aspect of pig performance or immune status.     

Folic acid and reproductive performances of sows

Two-hundred nine sows were used in a 2 X 2 split-plot unbalanced design to measure the effect of folic acid against control, and flushing against a normal level of feeding, between weaning and mating on the following variables: serum folates at weaning and at 60 d of gestation, blood hemoglobin (Hb) and hematocrit (Ht) after 15 wk of gestation and reproductive performance at farrowing. Folic acid was administered im according to a schedule that maintained serum folates at approximately the same level between weaning and 60 d of gestation. The treatments had no effect on Hb or Ht after 15 wk of gestation. Average live litter size was 12.0 piglets/litter for sows receiving the folic acid and flushing treatments as compared with 10.5 for sows without any treatment; the main effect of folic acid was significant (P less than or equal to .04). Intralitter variation in birth weight and total litter weight tended to be increased by folic acid administration. Results showed that the administration of folic acid during gestation could appreciably improve the reproductive performance of sows.     

The effects of pure nucleotides on performance, humoral immunity, gut structure and numbers of intestinal bacteria of newly weaned pigs

Weaning is often stressful for piglets and accompanied by morphological, histological, microbial, and immunological changes along the digestive tract. Dietary nucleotides are bioactive compounds which have the potential to diminish weaning-associated challenges. The experiment was carried out with 5 litters each of 7 pigs (mixed sex), weaned at 20 d of age. One baseline pig per litter was slaughtered at d 0. The remaining 30 pigs were housed individually and randomly allocated to 2 dietary treatments: the control diet or the control diet supplemented with a mixture of nucleotides. Measurements of growth performance traits included ADFI, ADG, G:F, and BW. At d 17, fresh fecal samples were taken to determine bacterial numbers. On d 19 and 20, pigs were slaughtered and blood samples were analyzed for plasma immunoglobulins and intestinal samples were assessed for morphological traits. Digesta from the jejunum and cecum were collected for analysis of the microbiome. The ADFI was greater in the nucleotide treatment compared with the control treatment (P < 0.05), but ADG, G:F, and BW did not differ between treatments. Plasma IgA concentrations increased with age and were greater in the nucleotide (P < 0.05) compared with the control group. There were no treatment differences in plasma IgG and IgM, gut morphology, or intestinal and fecal bacterial counts. Supplemental nucleotides may increase ADFI but without having any impact on growth performance of the pigs. Greater plasma IgA concentrations indicate that adding nucleotides in the weaning diet supported humoral immunity. However, there was no effect of dietary nucleotide supplementation on the composition of the bacterial community in parts of the small and large intestine. Further research is warranted before the use of nucleotide as a feed additive in pig diet can be recommended.     

谷氨酰胺对早期断奶仔猪生长性能及肠道形态发育的影响

选21日龄断奶的杜大长仔猪72头,按试验要求分为2组,每组3个重复,每重复12头。分别饲喂基础日粮和含1%谷氨酰胺(Gln)日粮,试验期21 d,在断奶后0 d、7 d和14 d分别屠宰取小肠测重,并取十二指肠、空肠、回肠测定绒毛高度和隐窝深度。试验结果表明:断奶后7 d,日粮中添加Gln可显著提高仔猪的平均日增重和小肠相对重量,提高十二指肠和空肠绒毛的高度,降低十二指肠和空肠的隐窝深度;断奶后14 d,日粮中添加Gln对断奶仔猪的生长和肠道形态发育影响与基础日粮组相比差异不显著。     

Control of the weaning-to-estrus interval in sows using gonadotropins and prostaglandins during lactation.

Two experiments were conducted to examine the effectiveness of various strategies using gonadotropins to induce ovulation during lactation as a means of controlling the weaning-to-estrus interval in sows. The objective of Exp. 1 was to examine the efficacy of various gonadotropin regimens for induction of ovulation during lactation. Primiparous (n = 60) and multiparous (n = 83) crossbred sows were assigned, before farrowing, to one of four treatments: no injection (control); 1,000 IU hCG on d 0 (hCG-0; d 0 = day of farrowing); P.G. 600 + 1,000 IU hCG 4 and 7 d after farrowing, respectively (hCG-7); or P.G. 600 + 1,000 IU hCG 11 and 14 d after farrowing, respectively (hCG-14). Sows were weaned on 18 +/- 2 d after farrowing and monitored daily for estrus via exposure to mature boars. The criterion for determining the induction of ovulation was a sustained increase in serum progesterone concentrations above 4.0 ng/mL. The most consistent response to exogenous gonadotropins was on d 0, with an 80% response in primiparous sows (12/15) and a 71% response in multiparous sows (15/21). Weaning-to-estrus intervals for multiparous sows were longer (P = .05) for hCG-14 and hCG-7 than for control and hCG-0 sows. Weaning-to-estrus intervals for primiparous sows were longer (P = .05) for the hCG-14 than for the hCG-0 treatment. The objective of Exp. 2 was to ascertain the effects of postpartum treatment with hCG (1,000 IU) on d 0 and PGF2alpha (10 mg) at d 14 on the weaning-to-estrus interval in multiparous sows weaned at d 14 after birth. Before farrowing, sows (n = 60) were randomly assigned to one of four treatments: positive control, weaning at d 21; negative control, weaning at d 14; hCG within 24 h after farrowing, weaning at d 14; or hCG within 24 h after farrowing and PGF2alpha at weaning, weaning at d 14. Weaning-to-estrus intervals were longer (P = .05) in sows receiving PGF2alpha than in the other treatments. Results indicate that it is possible to induce ovulation immediately after farrowing, using a single injection of hCG, and this strategy can be used to uncouple weaning from the resumption of reproductive activity. However, the administration of PGF2alpha at 14 d after farrowing did not consistently cause regression of the induced corpora lutea.     

Endocrine Responses to Weaning and Changes in Post-Weaning Diet in the Young Pig

The effects of weaning and changing post-weaning diet composition on growth patterns and growth-related hormonal profiles were evaluated in neonatal pigs. Forty-eight crossbred piglets were assigned to two groups (n = 24/group) based on weaning at 2 or 3 wk of age (2W and 3W groups, respectively). At weaning, piglets were removed from the sow and placed on a commercial starter ration for the first 11 d post-weaning (Phase I diet). At Day 12 post-weaning, pigs were placed on a growing ration for the remainder of the study (Phase II diet). Body weights and blood samples were collected twice weekly from birth until 42 d of age. Serum insulin-like growth factor (IGF)-1, IGF-2, and average daily gain (ADG) were reduced (P < 0.05) in both groups as a result of weaning, whereas serum growth hormone (GH) was elevated (P < 0.05). Earlier weaning resulted in a greater reduction in growth rate and serum IGF-2 values (P < 0.05). Mild reductions in ADG occurred after the Phase I to II dietary change in both weaning groups (P < 0.05), but serum IGF-1 decreased only in the 2W group (P < 0.05). Growth hormone concentrations tended to increase after the change in post-weaning diets (P = 0.07 and 0.16 in 2W and 3W, respectively). Serum thyroxine (T₄) and triiodothyronine (T₃) levels were unaltered by weaning but declined in both groups after the change in starter diets (P < 0.05). Changes in cortisol concentrations were not associated with weaning or the change in post-weaning diets. With the exception of serum IGF-1 concentrations, which were elevated in the 2W group, growth and endocrine endpoints were equivalent between experimental groups at the end of the study (42 d of age). These results indicate that earlier weaning and changing solid diets can more severely affect patterns of early growth and related hormone secretion, but effective compensatory mechanisms restore normal physiological and physical development.