肥育猪消化能需要量研究

选用体重约52kg的杜× (大×长)猪60头 ,分为6个处理组 ,每个处理组2个重复 ,分别饲以含消化能浓度不同的6组饲粮(各组饲粮中DE与CP、Lys、Met +Cys比例相同) ,研究52～90kg肥育猪DE需要量 ;同时采用体重71kg 的阉公猪36头 ,每组6头进行消化试验 ,测定各组饲粮的DE浓度及其对饲粮养分消化率和氮平衡的影响。结果表明 ,各组饲粮DE浓度分别为13.18、13.59、13.99、14.39、14.79、15.20MJ/kg。粗脂肪消化率随DE浓度的提高而极显著提高(P<0.01) ,当DE浓度从13.18MJ/kg 升高到14.39MJ/kg时 ,能量和干物质消化率极显著提高(P<0.01)、氮消化率和氮存留量显著提高(P<0.05) ,采食量和日增重趋于提高(P>0.05)、DE日摄入量极显著提高(P<0.01) ,进一步提高DE浓度 ,能量、干物质和氮消化率降低(P<0.05)、氮存留量趋于提高(P>0.05)、生产性能未能提高 ;氮存留效率和料重比各组间无显著差异(P>0.05)。DE浓度14.79MJ/kg组和15.20MJ/kg组血清甘油三酯和胆固醇含量显著高于其它组(P<0.05) ,DE浓度13.18MJ/kg组血清尿素氮含量显著低于其它组(P<0.05)。DE浓度13.18MJ/kg 组屠宰率略低于其它组(P>0.05)、胴体脂肪率极显著低于13.99MJ/kg 和14.79MJ/kg 组(P<0.01) ;13.18MJ/kg 和14.39MJ/kg组瘦肉率显著高于14.79MJ/kg 组(P<0.     

低聚糖对断奶羔羊小肠黏膜免疫相关细胞的影响

选用陶赛特F2代断奶公羔40只,随机分成4组,研究低聚糖对断奶羔羊小肠黏膜免疫相关细胞的影响。结果表明:日粮中添加低聚果糖FOS(0.3%)、低聚异麦芽糖IMO(0.3%)和复合低聚糖(0.1%FOS+0.2%IMO)均可提高断奶羔羊胸腺指数和脾脏指数(P>0.05)及小肠黏膜上皮内sIEL数量(P<0.05);FOS可提高小肠黏膜上皮GC的数量I,MO和复合低聚糖可降低GC数量(P>0.05)I;MO和复合低聚糖可提高断奶羔羊小肠黏膜中MC细胞的数量(P>0.05)。提示断奶羔羊日粮中添加低聚糖可增加其小肠黏膜免疫相关细胞的数量,增强断奶羔羊小肠黏膜免疫功能,提高其免疫力。     

Effects of dietary supplementation with l-arginine on the intestinal barrier function in finishing pigs with heat stress

Previous studies showed heat stress reduces body weight gain and feed intake associated with damaged intestinal barrier function, and l -arginine (L-Arg) enhanced intestinal barrier function in young animals under stress. The aim of this study was to evaluate effects of L-Arg on serum hormones, intestinal morphology, nutrients absorption and epithelial barrier functions in finishing pigs with heat stress. Forty-eight finishing pigs (Landrace) were balanced for sex and then randomly assigned to six groups: TN group, thermal neutral (22°C, ~80% humidity) with a basal diet; HS group, heat stress (cyclical 35°C for 12 hr and 22°C for 12 hr, ~80% humidity) with a basal diet; PF group, thermal neutral (22°C, ~80% humidity) and pair-fed with the HS; the TNA, HSA and PFA groups were the basal diet of TN group, HS group and PF group supplemented with 1% L-Arg. Results showed that HS decreased (p < .05) the thyroxine concentrations and increased (p < .05) the insulin concentrations in serum compared with the TN group, but 1% L-Arg had no significant effects on them. Both HS and PF significantly increased (p < .05) the mRNA expression of cationic amino acid transporters (CAT1 and CAT2) and decreased the mRNA expression of solute carrier family 5 member 10 (SGLT1) in the jejunum compared with the TN group. Compared with the TN group, HS reduced the expression of tight junction (TJ) protein zonula occluden-1 (ZO-1) and occludin, but PF only decreased ZO-1 expression in the jejunum. Results exhibited that dietary supplementation with 1% L-Arg improved the intestinal villous height, the ratio of villous height to crypt depth, and the expression of occludin and porcine beta-defensin 2 (pBD2) in the jejunum of intermittent heat-treated finishing pigs. In conclusion, dietary supplementation with 1% L-Arg could partly attenuate the intermittent heat-induced damages of intestinal morphology and epithelial barrier functions in finishing pigs.     

酿酒酵母和芽孢杆菌对育肥猪养分表观消化率、肠道形态结构和肠道免疫的影响

本试验旨在研究酿酒酵母和芽孢杆菌对育肥猪养分表观消化率、肠道形态结构和肠道免疫的影响。选取72头体重(62.50±0.83)kg的"杜×长×大"育肥猪,将其随机分为3组,每组4个重复,每个重复6头猪(公母各占1/2)。对照组饲喂基础饲粮,酿酒酵母组饲喂基础饲粮+0.5 g/kg活性干酵母制剂(酵母菌活菌数1.0×1010CFU/kg),芽孢杆菌组饲喂基础饲粮+0.1 g/kg芽孢杆菌制剂(芽孢杆菌活菌数1.0×109CFU/kg)。试验期56 d。结果表明:1)与对照组相比,芽孢杆菌组育肥猪钙和磷的表观消化率显著提高(P0.05),酿酒酵母组钙的表观消化率显著提高(P0.05);2)与对照组相比,酿酒酵母组育肥猪空肠隐窝深度极显著降低(P0.01),空肠绒毛高度/隐窝深度值极显著提高(P0.01);3)与对照组相比,芽孢杆菌组育肥猪空肠和回肠分泌型免疫球蛋白A(SIg A)含量均极显著上升(P0.01)。由此可见,饲粮中添加酿酒酵母和芽孢杆菌均可改善育肥猪对营养物质的消化吸收,其中酿酒酵母对育肥猪肠道形态结构具有一定的改善作用,而芽孢杆菌可提高肠道中的SIg A含量,提高肠道免疫水平。     

超声磁粒复合研磨加工工艺参数控制系统设计

在研究超声磁粒复合研磨工作原理基础上,结合传统磁粒研磨材料去除数学模型,探讨了超声振动对提高磁粒研磨效率的积极作用,揭示出主轴转速、供磁电流、加工间隙、超声功率等是影响超声磁粒复合研磨质量和效率的关键因素。运用现有数控铣床和工件表面精加工数控代码,结合软件技术设计了一套超声磁粒复合研磨加工工艺参数控制系统。实验证明,该控制系统可以实现自由表面超声磁粒复合研磨工艺参数的自动控制。     

Effects of organic chromium supplementation to ifnishing lambs diet on growth performance,carcass characteristics and meat quality

The objective of this study was to evaluate supplemental organic chromium (Cr) to ifnishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs (age (4.5±0.2)...     

Endocrine, haematological and metabolic responses to sevoflurane anaesthesia in lambs

Objective To compare the magnitude and duration of the peri‐operative haematological, endocrine and metabolic effects of surgery performed under sevoflurane anaesthesia. Study Design Prospective randomized study. Animals Ten, 55‐day‐old lambs of both sexes, mean weight 20.8 ± 0.3 kg (range 18.5–23.6 kg). Methods Animals were randomly allocated to two equal groups. All were anaesthetized with sevoflurane for 3 hours. Surgery (end‐to‐end anastomosis of the right carotid artery and right jugular vein) was performed in animals of Group 1 only. The electrocardiogram, pulse oximetry, cardiac output and noninvasive arterial blood pressure (NIBP) were monitored. Venous blood samples (5 mL) were taken 30 minutes before induction of anaesthesia (T = 0) and 1 (T1), 24 (T2), 48 hours (T3) and 7 days (T4) after anaesthesia in order to measure plasma cortisol, ACTH, insulin, cyclic adenosine monophosphate (cAMP), glucose, protein concentrations and haematological variables. Results Sevoflurane decreased NIBP (minimum mean value: 64 ± 3 mm Hg) in both groups. Plasma cortisol and ACTH concentration increased in Group 1 (maximum mean values: cortisol: 136.2 nmol L^?1, ACTH: 54.5 pmol L^?1) and Group 2 (maximum mean values: cortisol: 128.7 nmol L^?1, ACTH: 44.0 pmol L^?1). Cyclic AMP increased only in Group 1 (9.3 nmol) 1 hour after anaesthesia. Neutrophilia, lymphopaenia and a decreased PCV were observed in both groups 1 hour after anaesthesia. Plasma protein and glucose concentrations did not change. Conclusions Increased ACTH and cortisol concentrations recorded 1 hour after anaesthesia suggest that sevoflurane induces a stress response in lambs. Clinical relevance The study did not identify the mechanism by which sevoflurane induces a stress response although hypotension is implicated.     

Supplementation of protease,alone and in combination with fructooligosaccharide to low protein diet for finishing pigs

Effects of adding protease with or without fructooligosaccharide (FOS) to low protein diet on growth performance, nutrient digestibility and fecal noxious gas emission were evaluated in 160 finishing pigs (57.70 ± 1.16 kg) in a 9‐week study. Pigs were randomly divided into four dietary treatments, PC: positive control diet (15.97% crude protein (CP)); NC: negative control diet (12.94% CP); PRO: NC supplemented with 0.05% protease; PROFOS: NC supplemented with 0.05% protease and 0.1% FOS. During weeks 4–9 and weeks 0–9, gain : feed ratio was impaired (P < 0.05) in pigs fed NC diet compared with those fed PC, PRO and PROFOS diets. Pigs fed PC, PRO and PROFOS diets had higher (P < 0.05) apparent total tract digestibility (ATTD) of CP than pigs fed NC diet. Pigs fed PROFOS diet had reduced (P < 0.05) ammonia emissions compared to pigs fed NC and PRO diets. These data indicate that reducing dietary CP concentrations impaired growth performance, decreased ATTD of CP and reduced ammonia emissions. Supplementation of protease in low CP diet improved growth performance and increased ATTD of CP. Dietary supplementation with protease and FOS in low CP diet improved growth performance, increased ATTD of CP and decreased fecal ammonia emission.     

蓖麻餅去毒及其饲喂生长肥育猪效果的研究

本研究采用不同方法对蓖麻饼进行去毒处理,筛选出最优去毒方法,然后用脱毒和未脱毒蓖麻饼进行饲喂试验。试畜为内蒙黑猪仔猪,饲养试验分为豆饼组、蓖麻饼Ⅰ组(简称CBMI),CBMⅡ,CBMⅢ(每组6头)。20—50公斤体重阶段,去毒蓖麻饼分别占日粮0,5%,10%,15%。50—90公斤体重阶段,分别占0,10%、20%、30%。毒性试验分为两组(每组3头),未脱毒蓖麻饼分别占日粮20和30%。试验结果表明,膨化蓖麻饼,可除去蓖麻饼中89%的蓖麻碱和71%的变应原。试畜日增重,豆饼组、CBMⅠ、CBMⅡ、CBMⅢ分别为578.8、533、524、497克。经残毒分析,试畜心,肝、肾、肌肉等组织器官均无残毒。如果蓖麻饼不经去毒直接饲喂时,试畜心脏、肝、肾、甲状腺、淋巴结及消化道均出现病变。