Effect of faunation on ruminal solubility and liver content of copper in sheep fed low or high copper diets

Naturally fauna-free crossbred rams approximately 5 mo old, 49.3 +/- 1.88 kg live weight, were allotted to four groups. Two groups remained fauna-free, whereas the other two groups were faunated. A diet based on corn silage-soybean meal containing either a low or a high Cu concentration (7 or 15 micrograms/g dry matter) was fed ad libitum to the two groups for 197 d. The rams were killed at the end of the experiment and livers and ruminal contents were analyzed for Cu. Faunated sheep grew faster (P less than .01) and as a group consumed 1.53 kg diet dry matter daily compared with 1.34 for the fauna-free sheep. Faunated sheep had lower final liver Cu concentrations (P less than .01), total liver Cu per unit of Cu intake and ruminal Cu solubilities (P less than .01) when fed both low and high Cu diets. The relative hepatic Cu uptake was higher by rams fed the low Cu than by those fed the high Cu diet. The results are interpreted to show that faunation decreased the availability of Cu in sheep fed a corn silage-soybean meal diet. The magnitude of the effect was independent of the Cu concentration in the diet.     

Effects of 2-mercaptoethanol on the solubility of copper and zinc containing proteins in liver samples from normal and chronic copper poisoned sheep

The solubility of Cu and Zn binding proteins was studied in liver samples from clinically healthy and chronic copper poisoned sheep (CCP). Homogenized liver was divided by ultracentrifugation into cytosol and pellet. The cytosol was gelfiltrated, Cu and Zn contents were determined in the eluates as well as in the pellet. Liver homogenate, cytosol and pellet were treated with 2-mercaptoethanol (ME). The resulting clear solutions were fractionated by gel filtration followed by determination of the contents of the two metals in the eluates.In CCP sheep the solubility of Cu containing proteins from the liver homogenate and pellet increased after incubation with ME.The results suggest that in CCP sheep a considerable amount of Cu containing proteins are present in an insoluble form, which to some extent is resolubilized by ME.     

Effects of concurrent copper deficiency and gastro-intestinal nematodiasis on circulating copper and protein levels, liver copper and bodyweight in sheep

Sheep were rendered hypocupraemic using parenteral ammonium tetrathiomolybdate (ATM). Fifteen thousand third stage larvae of Trichostrongylus axei and T. colubriformis in the ratio 1:1 were administered three times per week for six weeks, starting four weeks after cessation of ATM treatment. The changes in liver and plasma copper (Cu), caeruloplasmin activity, serum proteins, faecal nematode egg counts and total nematode counts were measured in the sheep for 10 weeks after infection. Decreases in liver Cu, plasma Cu and caeruloplasmin activities were detected soon after infection. There was a significant (P less than 0.05) interaction of the effects of Cu deficiency and nematode infection on these changes. Hypoproteinaemia, attributed to serum albumin loss, was demonstrated seven weeks after infection, but this was not associated with the interaction of Cu deficiency and nematode infection. No changes in serum globulins were detected. Although the results support the contention that gastro-intestinal nematodiasis can significantly exacerbate an existing Cu deficiency in sheep, there was no evidence that hypocuprosis would predispose sheep to higher nematode burdens.     

Effects of dietary copper on production and egg cholesterol content in laying hens

1. This experiment was carried out to determine the effects of diets supplemented with different amounts of copper on egg production, food intake, food conversion ratio, egg weight, damaged egg ratio, specific gravity, mortality and cholesterol concentration in yolk. The experiment lasted 90 d and 400 Hisex-Brown hens, aged 27 weeks at the start of the study, were used. 2. There were no statistically significant effects of supplementary copper on egg production, food intake or food conversion efficiency. 3. There were no statistically significant differences between the groups in terms of damaged eggs, egg weight, specific gravity and live weight. 4. At the end of the experiment, the lowest yolk cholesterol concentrations were obtained in the 150 kg/kg copper group and the greatest concentrations were in the control group. 5. Consequently, the use of supplementary copper to provide 150 kg/kg in poultry diets was concluded to decrease yolk cholesterol concentrations without any effect on production performance.     

Effects of dietary protein content on renal parameters in normal cats

This study evaluates the effect of dietary protein content on renal parameters in 23 healthy spayed female cats. The objective was to determine if cats eating diets high in protein will have higher serum urea nitrogen (UN) and creatinine values without a detectable change in kidney function, as assessed by urinalysis. A single random cross-over design was used. Cats were fed a standard maintenance diet for at least 1 month prior to the dietary trial. They were fed in two phases. For the first phase, cats were randomly assigned to receive either a high protein [HP=46% metabolizable energy (ME)] or low protein (LP=26% ME) diet. For the second phase, cats were fed whichever diet they were not fed during the phase I period. Blood and urine samples were collected at 2-week intervals for the duration of the study (10 weeks). UN, albumin, alanine aminotransferase and urine specific gravity were significantly higher, and creatinine and phosphorus were significantly lower (P<0.05) when cats were fed the HP diet as compared to when they were fed the LP diet, although none of the mean values were found to be outside of the corresponding reference interval. Dietary intake can result in clinically significant changes in UN and statistically significantly changes in several other biochemical analytes, although all analytes are likely to remain within normal reference intervals. Therefore, an accurate dietary history is necessary to help determine if renal parameters are being influenced by diet in a particular patient.     

Effects of dietary copper and molybdenum on tansy ragwort (Senecio jacobaea) toxicity in sheep

Dried tansy ragwort (Senecio jacobaea), which contains pyrrolizidine alkaloids (PA), was fed to sheep to determine whether PA consumption influenced liver Cu concentrations. Nine Polypay wether lambs were allotted to 3 groups according to the diets: control diet + 50 micrograms of Cu/g of feed (control + Cu); tansy ragwort (TR) diet + 50 micrograms of Cu/g of feed (TR + Cu); and TR diet + 50 micrograms of Cu/g of feed and 10 micrograms of Mo/g of feed (TR + Cu + Mo). Liver Cu concentrations were sharply increased (13-fold) after 8 weeks of feeding the diets, and then decreased slightly. There were no significant differences in concentrations of liver Cu among treatment groups. All lambs in the group fed TR + Cu + Mo died by the end of 23 weeks, with the usual signs of PA poisoning, including liver necrosis, hepatic megalocytosis, and biliary hyperplasia. The TR intake was about 2.7 to 3.0 kg/kg of their initial body weight. All lambs in the group fed the control + Cu diet survived. The results indicated that sheep fed TR do not preferentially accumulate liver Cu. There was an indication that dietary Mo increased susceptibility to TR intoxication.     

Effects of dietary protein and carbohydrate source on rumen fermentation and nutrient flow in sheep

The effects of decreasing levels of rumen degradable protein (RDP) and nonstructural carbohydrate (NSC) (Diet 1: 74% RDP and 38% NSC; Diet 2: 57% RDP and 32% NSC; Diet 3: 48% RDP and 23% NSC) were studied in cannulated sheep. Total volatile fatty acid (VFA) content rose in response to increasing NSC content. The molar ratio of acetate to propionate was the narrowest for Diet 1. Ruminal concentrations of ammonia and urea increased in response to the rising level of RDP. Flow of organic matter (OM) to the duodenum was increased for Diet 3, which resulted in the lowest apparent and true ruminal digestion of OM. Duodenal flow of total nitrogen (N) increased as RDP content decreased. The highest quantity of undegraded feed protein in duodenal digesta was measured in sheep fed Diet 3. Microbial N flow and microbial efficiency were unaffected by the diets. These results indicate that an NSC level lower than 25% and an RDP content lower than 50% did not exert any negative effect on microbial N production. This phenomenon supports the theory that if the level of RDP is lowered with a concomitant decrease in NSC, uncoupled fermentation cannot be observed.     

不同剂量的蛋氨酸铜对肉鸡肝脏病理组织结构和粪便铜含量的影响

选择1日龄健康AA肉仔鸡120只,随机分成4组。使用蛋氨酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11mg/kg,3个高铜试验组分别为:110mg/kg、220mg/kg和330mg/kg,试验至60日龄结束。于第12,36,60日龄在各组内随机采血,测定血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)活性;测量60日龄各组肝脏和粪便的铜含量并观察肝脏组织病理变化。结果显示:①血清ALT和AST活性均在正常范围内,没有异常升高;②110mg/kg和220mg/kg组的肝脏组织中铜含量比对照组有所升高,但是差异不显著(P>0.05),而330mg/kg组则极显著高于其他3个试验组(P<0.01);110mg/kg,220mg/kg和330mg/kg组的粪便中铜含量均极显著高于对照组(P<0.01);③330mg/kg组的肝脏组织大部分细胞中度变性,其他各组病理变化不明显。试验结果表明,日粮中蛋氨酸铜浓度达到330mg/kg时,肝脏内的铜蓄积量会迅速增多且对肝脏造成较大的损伤,粪便中的铜含量随着日粮中铜含量的增加而迅速增多,可能对环境造成不利影响。     

高铜对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响

选用1日龄健康AA肉鸡120只随机均分成4组,使用硫酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11mg/kg,3个试验高铜组饲料铜含量分别为110,220,330mg/kg,试验至60日龄结束,来探讨高铜日粮对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响。结果显示:(1)随着铜浓度的增加和/或饲养日龄的延长,线粒体膜通透性转换孔(Mitochondrial permeability transition pore,MPTP)逐渐扩大(P0.05);(2)血清总胆固醇(T-Ch)含量110,220mg/kg铜添加组低于对照组(P0.05),330mg/kg铜添加组极显著低于对照组(P0.01),而甘油三酯(TG)的含量在各高铜组均极显著低于对照组(P0.01);(3)与对照组相比,肝脏铜含量110,220mg/kg铜添加组有所增加(P0.05),330mg/kg铜添加组极显著增加(P0.01),肌肉中铜含量在各高铜组均极显著高于对照组(P0.01)。这说明高铜可造成肝线粒体不同程度的肿胀和损伤,改变肉鸡脂类的新陈代谢,明显增加肝和肌肉组织的铜含量。     

日粮粗蛋白质水平对羊养分瘤胃降解率的影响

为了研究日粮粗蛋白质水平对羊养分瘤胃降解率的影响,为优化羊日粮蛋白质水平提供依据,试验采集小尾寒羊瘤胃液,借助体外模拟培养技术,对4种粗蛋白质水平(12%、14%、16%、18%)日粮的养分瘤胃降解率进行研究。结果表明:日粮粗蛋白质水平对DM降解率没有显著影响,但对CP、NDF和ADF降解率影响显著。结果提示,提高羊日粮的粗蛋白质水平有利于营养物质在瘤胃中降解,日粮粗蛋白质水平为16%时对提高羊的养分瘤胃降解率较为适宜。     

饲粮蛋白质水平对藏系绵羊瘤胃真菌菌群结构及功能的影响北大核心CSCD

本研究旨在探究饲粮蛋白质水平对藏系绵羊瘤胃真菌菌群结构及功能的影响。试验选取18只12月龄健康、平均体重为(31.71±0.72)kg的藏系绵羊羯羊,随机分为3组,每组6只,分别饲喂代谢能相近而蛋白质含量不同(LP组,10.06%CP;MP组,12.10%CP;HP组,14.12%CP)的饲粮,试验为期120 d,包括15 d的预饲期和105 d的正试期。结果表明:1)LP组藏系绵羊的终末体重、平均日增重和平均日采食量均显著低于MP组和HP组(P<0.05),而料重比显著高于MP组和HP组(P<0.05)。2)3组18个瘤胃液样品共产生1547415条有效序列,聚类后共得到4073个OTUs。饲粮蛋白质水平并没有对藏系绵羊瘤胃真菌多样性指数产生显著性影响(P>0.05)。3)在门分类水平上,藏系绵羊瘤胃真菌优势菌门为子囊菌门、担子菌门、被孢霉亚门和新美鞭菌门等;在属分类水平上,瘤胃真菌优势菌属为青霉属、无茎真菌属、枝孢属、镰孢霉属和链格孢属等。4)采用LEfSe方法对各个分类水平上丰度有显著差异的微生物进行比较分析,共筛选到33个符合生物标记物的真菌菌群。5)基于FUNGuid对藏系绵羊瘤胃真菌群落的营养型进行功能预测,发现腐生营养型是最主要的营养型。以上结果表明,适当提高饲粮中蛋白质水平可以显著提高藏系绵羊的生长性能,但对瘤胃真菌菌群的多样性和结构组成并未产生明显的影响。     

Effects of dietary vitamin and fatty acid content in E on muscle vitamin E Aohan fine-wool sheep

Background： Increasing the polyunsaturated fatty acid （PUFA） content and decreasing the saturated fatty acid （SFA） content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid （FA） composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep. Methods： Forty-two male Aohan fine-wool lambs （5 mo old） with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 （control group）, 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the Iongissimus lumborum （LL） and gluteus medius （GM） muscles. Results： Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation （P 〈 0.05）. However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA （MUFA） content in the LL and GM （P 〈 0.05）. All six doses of vitamin E significantly increased cis9 tronsl -conjugated linoleic acid （cgtl -CLA） content in the LL compared with the control group （P 〈 0.05）. Conclusions： Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c9tl 1-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E.     

Effects of dietary vitamin E on muscle vitamin E and fatty acid content in Aohan fine-wool sheep

Background

Increasing the polyunsaturated fatty acid (PUFA) content and decreasing the saturated fatty acid (SFA) content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid (FA) composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep.

Methods

Forty-two male Aohan fine-wool lambs (5 mo old) with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 (control group), 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the longissimus lumborum (LL) and gluteus medius (GM) muscles.

Results

Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation (P < 0.05). However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA (MUFA) content in the LL and GM (P < 0.05). All six doses of vitamin E significantly increased cis9 trans11-conjugated linoleic acid (c9t11-CLA) content in the LL compared with the control group (P < 0.05).

Conclusions

Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c9t11-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E.     

日粮中添加高水平纳米硒对蛋鸡肝脏硒含量及抗氧化能力的影响

选取288只42周龄健康农大三号商品蛋鸡,随机分为6个组,每组设4个重复,在基础日粮中以亚硒酸钠的形式添加硒0.3 mg/kg;其余各组以纳米硒的形式分别添加硒0.3、0.5、2.5、5.0、10.0 mg/kg.试验期为60 d.结果显示:试验至30 d,添加0.5～10.0 mg/kg纳米硒能显著提高肝脏硒的含量,添加纳米硒能显著提高T-AOC活性(P<0.05),极显著提高T-SOD活性(P<0.01).试验至60 d,添加2.5～10.0 mg/kg纳米硒能极显著提高GSH-Px活性,添加0.5～10 mg/kg极显著降低NO含量(P<0.01).结果表明,日粮中添加高水平的纳米硒能提高蛋鸡肝脏的抗氧化能力.     

Effects of dietary protein level and clinoptilolite on the weight gain and liver mineral response of growing lambs to copper supplementation

Growing male Synthetic I (1/2 Finnish Landrace x 1/4 Dorset x 1/4 Rambouillet) lambs were used in two experiments (64 lambs in Exp. 1 and 63 in Exp. 2) to test the hypothesis that dietary CP level (9 or 14% of diet as fed) and(or) clinoptilolite (clino; 0 or 2% of diet) affects growth and tissue mineral concentrations of growing lambs fed supplemental Cu. Lambs were individually fed their respective diets ad libitum and killed after 12 wk (Exp. 1) or 16 wk (Exp. 2) to obtain carcass measurements, organ weights and liver mineral concentrations. In Exp. 1, 20 ppm added Cu (as CuSO4.5H2O) increased mortality and depressed BW gain (P less than .01) and daily feed intake (P less than .05) in the presence or absence of clino and at both levels of CP. Liver Cu concentration was greater (P less than .01) in lambs fed added Cu than in those not fed Cu (408 ppm vs 110 ppm, respectively). Neither CP nor clino affected liver Cu concentration. Clinoptilolite increased daily gain of lambs fed high CP but not low CP (P less than .01). In Exp. 2, clino in the diet had no effect on daily gain or daily feed, but 20 ppm Cu addition depressed daily gain (P less than .01) and gain/feed (P less than .07). Organ weights and levels of trace elements other than Cu in the liver generally were not affected by diet in either experiment. It is concluded that high dietary CP or 2% dietary clino did not protect against toxic signs of Cu when Cu was added to the basal diet (10 ppm Cu) at 10 or 20 ppm.     

硼对铜中毒肉用乌骨鸡肝铜含量及肝功能的影响

选用560只1日龄肉用乌骨鸡,采用二因子多水平随机化试验设计来探讨日粮硼对铜中毒肉鸡肝铜及肝功能的影响.试验中分别在玉米-豆粕型基础日粮中(50.9 mg/kg Cu,10.1 mg/kg B)添加549.1,749.1 mg/kg的铜和49.1,109.1 mg/kg的硼.结果表明,硼可在一定程度上抵御高铜对肝细胞的毒害,并减少肉鸡肝铜的蓄积量;说明硼对肉用乌骨鸡铜中毒具保护效应.     

蛋氨酸铜对绵羊增重及体内代谢的影响

26只晋中绵羊随机分为试验组(添加蛋氨酸铜)和对照组(添加硫酸铜),供试日粮及营养水平完全相同,试验时间60d。结果表明,试验组比对照组绵羊平均日增重提高34.22%(P<0.05);平均日粮干物质采食量、肝脏铜和血浆铜含量明显提高(P<0.05)。     

Effects of oscillating dietary protein on ruminal fermentation and site and extent of nutrient digestion in sheep

Eight cannulated wethers (BW = 52.5 +/- 5.7 kg) were used in a replicated 4 x 4 Latin square designed experiment to evaluate the effects of oscillating dietary protein concentrations on ruminal fermentation, site and extent of digestion, and serum metabolite concentrations. Four treatments consisted of a 13, 15, or 17% CP diet fed daily or a regimen in which dietary CP was oscillated between 13 and 17% on a 48-h basis (ACP). All diets consisted of 65% bromegrass hay (10.5% CP, 61.9% NDF, 37.2% ADF) plus 35% corn-based supplement and were formulated to contain the same amount of degradable intake protein (9.6% of DM) plus additional undegradable intake protein (SoyPLUS, West Central Cooperative, Ralston, IA) to accomplish CP levels above 13%. Each of four experimental periods were 16 d in duration with 12 d for diet adaptation followed by 4 d for sample collection. All wethers were fed at 3.0% of initial BW (DM basis) throughout the experiment, resulting in an average organic matter intake of 1.39 kg/d across treatments. When compared to the 15% CP daily treatment, feeding ACP had no effect (P > or = 0.10) on ruminal or lower tract N, NDF, ADF, or OM digestion. True ruminal OM digestion responded quadratically (P = 0.07) to increasing dietary CP, reaching a maximum of 52.0% of OM intake with the 15% CP treatment. Sheep fed ACP tended to have lower (P = 0.08) ruminal NH3 N concentrations and an overall higher (P = 0.0001) molar proportion of acetate compared to those fed 15% CP daily. Total VFA concentrations were not affected (P > or = 0.45) by increasing dietary CP. Microbial efficiency did not differ (P > or = 0.55); thus, bacterial N flow at the duodenum responded quadratically (P = 0.04) to increasing dietary CP. Nonbacterial N (P = 0.001) and total N (P = 0.01) flows at the duodenum and total tract N digestibility (P < or = 0.04) increased linearly as dietary CP increased. Wethers fed ACP maintained a lower (P = 0.002) serum glucose and lower (P = 0.0006) serum urea N compared to those fed 15% CP daily. Because the CP content of the diet was increased at the expense of corn, the response to increased CP observed in this experiment is most likely due to negative associative effects of supplemental starch on ruminal fermentation and microbial growth. Oscillating the CP content of the diet on a 48-h basis has little effect on digestion or N utilization in sheep compared with feeding the same quantity of protein on a daily basis.