投硒后放牧牦牛血硒浓度的变化

为了解牦牛补硒后血中硒浓度变化,对放牧牦牛按每100kg体重20mg,肌肉注射亚硒酸钠投硒,投药后每间隔1周进行采血,对6周间全血,血浆中硒浓度的变化进行了测定。结果表明:血浆中硒浓度随投硒显著上升(P<0.01),第1周后增至投予前的约3倍,第2周后现最大值(91.46±14.63μg/kg),第3周后开始下降,至4周后降至投前的水平;全血中Se浓度与血浆同样增大,投予后第2周时呈现最大值(129.81±36μg/kg)以后,血中硒浓度至第6周时仍维持107.55μg/kg的高值,约为对照群的3倍,至52周后投硒群牦牛血液中硒浓度仍为对照群的约2倍。试验期间,对照群血液、血浆中硒浓度均无显著变化。     

纳米硒对仔猪生长和抗氧化的影响

将纳米硒和亚硒酸钠2种硒源分别以0.1、0.2、0.3、0.4、0.5、1.0 m g/kg 6个硒水平添加到基础日粮中,配制成12种试验日粮,研究纳米硒和亚硒酸钠对断奶仔猪生长和抗氧化的影响。结果显示:硒源添加浓度在0.1￣0.3 m g/kg时,亚硒酸钠和纳米硒对仔猪生长性能、总抗氧化能力(T-AO C)、丙二醛(M D A)和活性氧含量的影响无显著差异(P>0.05);硒源添加浓度在0.4￣1.0 m g/kg时,纳米硒组仔猪生长性能、T-AO C显著(P<0.05)高于亚硒酸钠组,M D A和活性氧含量显著(P<0.05)低于亚硒酸钠组;硒源添加浓度在0.10￣0.40 m g/kg时,2种硒源对谷胱甘肽过氧化物酶(G SH-Px)活性的影响无显著差异(P>0.05);在0.50、1.0 m g/kg硒添加水平上,纳米硒组G SH-Px活性显著(P<0.05)高于亚硒酸钠组。上述结果提示:纳米硒的W einberg剂量-效应的最适剂量范围宽于亚硒酸钠。     

不同硒源对肥育猪鲜肉肉色和滴水损失的影响

选用108头体重60kg左右的杜×长×大三元杂交肥育猪,按饲养试验要求分成3组,对照组不添加硒(基础日粮中Se的实测值为0.045mg/kg),亚硒酸钠和硒代蛋氨酸试验组均添加0.30mg/kg硒,进行为期40d的饲养试验,然后屠宰并取样测定,研究不同硒源对肥育猪鲜肉肉色和滴水损失的影响及机理。结果表明:(1)硒代蛋氨酸使猪宰后第0.75、8、16小时肉色Huntera值显著升高(P<0.05),而亚硒酸钠仅使第0.75小时肉色Huntera值明显提高(P<0.05);(2)硒代蛋氨酸使猪宰后第8、16小时鲜肉的滴水损失显著减少(P<0.01),而亚硒酸钠有这一作用趋势,但效果不明显(P>0.05);(3)硒代蛋氨酸和亚硒酸钠均使血清和组织中硒含量增加(P<0.01),使肝脏、肌肉中谷胱甘肽过氧化物酶活力增强(P<0.01),丙二醛含量降低(P<0.01),但硒代蛋氨酸的这一作用较亚硒酸钠明显。     

不同硒水平对幼鲤生产性能和免疫功能的影响

选择体重约10.4 g的健康幼鲤960尾,随机分为8组,每组3个重复,每个重复40尾,分别饲喂添加硒(亚硒酸钠,分析纯)0、0.1、0.2、0.3、0.4、0.5、0.6、0.7 mg/kg的8种不同饵料,试验期90 d。结果表明:随着饵料中硒添加水平的增加,幼鲤的增重和成活率提高,饵料系数降低,添加硒0.4mg/kg时,幼鲤生产性能最佳(P<0.05);添加0.3～0.5 mg/kg硒,可显著提高幼鲤头肾和脾脏重及其体指数,增加血液红细胞数量,降低白细胞数量,提高血清IgM水平和攻毒后成活率、血清溶菌酶活力及血清凝集抗体效价(P<0.05),从而增强幼鲤免疫功能和对疾病的抵抗力。幼鲤体增重、饵料系数、头肾重量、脾脏重量、血清溶菌酶活力和IgM抗体水平与饵料硒添加量呈显著的二次曲线相关。根据上述指标确定的最适硒水平为0.396～0.529 mg/kg。     

不同硒水平对山羊生长性能和血液理化指标的影响

研究在基础日粮中添加不同水平亚硒酸钠对山羊生长发育、血液理化指标及抗氧化的影响。结果表明:在基础日粮中分别添加0.1、0.3mg/kg和0.5mg/kg亚硒酸钠组与基础日粮组相比,羔羊的平均日增重显著增加(P<0.05),以0.3mg/kg亚硒酸钠组增加幅度最大,增加了42.20%(P<0.05);饲料转化率分别提高了18.51%(P>0.05)、40.74%(P<0.05)和29.63%(P<0.05);0.3mg/kg亚硒酸钠组血液中WBC、RBC和血清中TP、ALB、GLO含量显著提高(P<0.05),血清尿素氮的水平显著降低(P<0.05),血清SOD和GSH-Px活性显著升高(P<0.01),血清MDA含量显著降低(P<0.01)。因此,添加亚硒酸钠促进蛋白质合成,改善机体抗氧化功能,促进羔羊生长发育,且以在基础日粮中添加0.3mg/kg最佳。     

硒代蛋氨酸对肥育猪生产性能和肉品质的影响

本试验旨在研究硒代蛋氨酸对肥育猪生产性能和肉品质的影响.选用64头体重约60 kg的杜×长×大三元杂交肥育猪,随机分为4个处理,各处理饲粮中分别添加0(空白对照组)、0.15和0.30 mg/kg硒代蛋氨酸硒、0.30 mg/kg亚硒酸钠硒,试猪体重达95 kg左右结束试验.结果表明:1)饲粮添加不同水平硒代蛋氨酸或亚硒酸钠均未改善肥育猪平均日增重、平均日采食量、料重比(P>0.05);2)饲粮添加不同水平硒代蛋氨酸或亚硒酸钠均未显著影响肥育猪背最长肌剪切力、肌内脂肪含量和滴水损失(P>0.05);各硒处理宰后12 h背最长肌pH均显著高于对照组(P<0.05);与对照组相比,添加硒代蛋氨酸或亚硒酸钠显著降低了宰后不同时间点肉色亮度(L*)值(P<0.05),提高了肉色红度(α*)值(P<0.05),0.15 mg/kg硒代蛋氨酸硒处理也显著降低了宰后12 h肉色黄度(b*)值(P<0.05);3)添加0.30 mg/kg硒代蛋氨酸硒显著降低了背最长肌中乳酸含量(P<0.05);0.30 mg/kg硒代蛋氨酸硒处理和0.30 mg/kg亚硒酸钠硒处理的氧合肌红蛋白含量均极显著高于对照组(P<0.01)和显著高于0.15 mg/kg硒代蛋氨酸硒组(P<0.05).以上试验结果提示,在肥育猪日粮中添加0.15～0.30 mg/kg硒代蛋氨酸硒对改善猪肉肉色十分有利.     

饲粮硒来源及添加水平对仔猪组织中细胞内谷胱甘肽过氧化物酶基因mRNA表达的影响

本文旨在研究饲粮中硒来源及添加水平对仔猪细胞内谷胱甘肽过氧化物酶(GPX1)mRNA表达的影响,为合理利用各种硒源提供一定的理论基础.选择35日龄体重相近的三江白猪仔猪90头,随机分为10组,每组3个重复,每个重复3头猪.分别在9个试验组饲粮中添加纳米硒、酵母硒、亚硒酸钠,其剂量以硒计,添加量分别为0.1、0.3、0.5 mg/kg 3个水平,对照组饲粮中不另添加硒.试验期为35 d,试验结束后采用反转录RT-PCR技术测定仔猪肝脏、肾脏、脾脏、肌肉组织中GPX1 mRNA的表达量.结果表明:1)在肝脏组织中,0.5 mg/kg纳米硒组GPX1 mRNA表达量显著高于亚硒酸钠组(P<0.05),0.5 mg/kg纳米硒组和0.3 mg/kg酵母硒组显著高于对照组(P<0.05);2)在肾脏组织中,各试验组之间GPX1 mRNA表达量差异均不显著(P>0.05);3)在脾脏组织中,0.5 mg/kg纳米硒组GPX1 mRNA表达量显著高于酵母硒组和亚硒酸钠组(P<0.05),0.5 mg/kg纳米硒组和0.3 mg/kg酵母硒组显著高于对照组(P<0.05);4)在肌肉组织中,0.5 mg/kg纳米硒组GPX1 mRNA表达量显著低于亚硒酸钠组和对照组(P<0.05).由此可见,在饲粮中添加0.5 mg/kg纳米硒能够提高仔猪肝脏、脾脏中GPX1 mRNA的表达量,而肌肉组织中的表达水平则低于亚硒酸钠组和对照组.     

硒对STZ诱发糖尿病大鼠骨密度影响的研究初报

比较了在低硒饲料的基础上补充不同形态硒对糖尿病大鼠骨密度的影响。健康SD大鼠 1 2 8只 ,体重 50～ 60 g,随机分为 4组 ,每组 32只 ,雌雄各半 ,其中Ⅰ组为低硒对照组 (饲料含硒量 0 0 37mg/kg) ;Ⅱ组为补充亚硒酸钠组 (饲料含硒量 0 3mg/kg) ;Ⅲ组为补充富硒麦芽组(饲料含硒量 0 3mg/kg) ;Ⅳ组为补充富硒酵母组 (饲料含硒量 0 3mg/kg)。Ⅱ、Ⅲ、Ⅳ组的饲料均是在Ⅰ组低硒饲料的基础上分别添加适量的亚硒酸钠、富硒麦芽、富硒酵母后配制而成。喂饲 5周后 ,Ⅰ、Ⅱ、Ⅲ、Ⅳ组用链脲佐菌素 (streptozotocin ,STZ)按 60mg/kg腹腔注射诱发糖尿病 ,继续饲喂 6周。用单光子吸收法测定各组大鼠的肱骨、股骨、胫骨、桡骨的骨密度。结果表明 :①STZ致糖尿病大鼠的骨密度随时间的延长有逐渐下降的趋势。Ⅱ、Ⅲ、Ⅳ补硒组大鼠可以在一定时间内延缓STZ致糖尿病大鼠的骨密度下降。在此期间骨密度的下降以肱骨出现最早 ,股骨次之 ,桡骨、胫骨再次之。②饲料补硒组糖尿病大鼠的肱骨、股骨中硒的含量较饲料低硒组糖尿病大鼠的肱骨、股骨中硒的含量显著提高。③补充硒的形态 ,即有机硒 (富硒麦芽、富硒酵母 )或无机硒 (亚硒酸钠 )对糖尿病大鼠肱骨、股骨、胫骨、桡骨的骨密度影响差异不显著。     

赛乐硒对西门塔尔牛矿物质存留率的影响

选用7头体重420kg,2．5岁的西门塔尔牛,采用7×7拉丁方设计．研究日粮添加赛乐硒（7．5、15和22．5mg硒／d）和亚硒酸钠（7．5、15和22．5mg硒／d）对日粮矿物质存留率的影响。结果表明：赛乐硒各组硒的表观存留率较亚硒酸钠组和对照组显著提高,钙、磷、锌和铜表观存留率较亚硒酸钠组提高。铁、钼和硫表观存留率无显著变化。赛乐硒组血清硒浓度较亚硒酸钠组显著提高,血清铁浓度无显著变化,赛乐硒组血清铜浓度增加。以上结果表明赛乐硒较无机硒能更有效促进矿物质的消化与利用,硒适宜添加量为7．5～15mg／d。     

含硒型牛副伤寒活疫苗对牦牛免疫效果的观察

硒是牛体不可缺少的微量元素之一。据调查我国约有2／3的地区缺硒。据李文盛等研究表明，甘肃省甘南州、张掖市、肃南等牦牛主要繁殖生产区为硒的严重患病区，土壤水溶性硒在0．010μg／g左右。饲草饲料硒在0．03lμg／g以下，畜禽血硒在0.075μg／ml以下；同时牛副伤寒也是该地区牦牛的高发病，每年的发病率平均约在30％以上。缺硒可影响牛体的正常发育、繁殖、免疫抵抗力，严重时可导致疾病的发生，甚至引起死亡。而通常采取的预防缺硒措施是在精粮或饮水中添加一定量的亚硒酸钠，可起到良好的预防效果，但在牦牛主产区以自由放牧为主，日粮添加亚硒酸钠拌不均或饮水剂量难以掌握，且亚硒酸钠补硒后血硒浓度在临界水平以上的持续时间短等原因，难以在牦牛饲养管理上应用。     

Scrapie in goats in Cyprus

Ovine scrapie was first recorded in Cyprus in 1985. Subsequently four dairy goats kept in two mixed flocks with affected sheep developed characteristic clinical signs similar to those seen in sheep. Fifteen goats from the two flocks were examined histologically and neurological lesions consistent with a diagnosis of scrapie were found in the four animals and in three others which had subsequently developed early neurological signs. These lesions were similar to those of naturally-affected sheep although neuronal degeneration and vacuolation were more severe in some cases.     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.