Effects of replacing a dietary antibacterial agent (zinc bacitracin) with copper salts in Cherry Valley Pekin meat ducks

1. A study was conducted to investigate the effectiveness of high dietary copper concentrations obtained from tribasic copper chloride (TBCC, 58% copper) and copper sulphate pentahydrate (CuSO₄, 25% copper) in replacing antibiotic growth promoters (AGP) in duck diets.

2. A total of 960 one-day-old Cherry Valley meat-strain ducks were divided into 3 treatment groups, with 8 replicates per treatment, in a 6-week feeding trial. The ducks were fed a basal diet supplemented with AGP (40?mg zinc bacitracin/kg and 40?mg garlicin/kg of diet) or 150?mg of Cu/kg of diet, given as either CuSO₄ or TBCC.

3. The body weight, average daily gain, average daily feed intake and mortality of ducks were not affected by the dietary treatments. However, the feed/gain ratio of ducks that were fed TBCC diets was significantly lower than those of ducks that were fed CuSO₄ diets and were similar to those in the AGP group.

4. TBCC increased the Cu content in the liver tissue of ducks compared with the content in those that were fed the diet supplemented with AGP. TBCC also increased the Fe and Zn content in breast muscles compared with that in ducks that were fed the diet supplemented with CuSO₄.

5. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly higher in the serum of ducks that received the diet supplemented with TBCC than AGP or CuSO₄. TBCC treatment decreased the malondialdehyde (MDA) content in serum of ducks compared with groups supplemented with CuSO₄.

6. No significant difference was observed in liver or muscle fat content among the different dietary treatment groups. The serum low-density lipoprotein cholesterol concentration was lower in ducks fed AGP diets than those fed CuSO₄ diets.

7. It was concluded that the replacement of AGP with 150?mg of Cu/kg of feed from TBCC improved the feed efficiency, trace mineral deposition and antioxidant status more than when the source of copper was CuSO₄.     

Growth response, blood characteristics and copper accumulation in organs of broilers fed on diets supplemented with organic and inorganic dietary copper sources

1. A 56-d experiment was conducted to study the comparative influence of organic and inorganic dietary copper (Cu) sources on growth, blood characteristics and copper accumulation in organs of broilers. 2. A total of 480 Arbor-Acre unsexed broilers were fed on diets containing copper sulphate (CuSO(4)) or copper proteinate (Cu Pro) at concentrations of 50, 100 or 150 mg/kg of Cu supplementation. The birds were given a broiler starter diet from 1-28 d and a broiler finisher diet from 29-56 d which contained 30·8 mg/kg and 41·1 mg/kg basal copper concentration respectively. Growth performance, blood characteristics and Cu accumulation in organs of the broilers were measured. 3. At 28 d, Cu Pro-fed birds had improved feed conversion ratio compared with CuSO(4). At 56 d, birds fed on Cu Pro diets had significantly greater body weight than CuSO(4)-fed birds. Birds fed on CuSO(4) supplemented diets had significantly better feed conversion efficiency. Feed consumptions for the two Cu sources were not significantly different. At no stage did the concentration of added Cu affect the productive traits measured. 4. Cu Pro supplementation increased haemoglobin concentration but reduced plasma triglyceride and plasma cholesterol. Plasma cholesterol decreased as Cu concentration increased. 5. There was a greater accumulation of Cu in the blood, heart, lung, liver and bone of broilers fed on Cu Pro than in those receiving CuSO(4). The liver Cu concentration increased as dietary Cu concentration increased. 6. Cu Pro was more effective in promoting growth and reducing blood cholesterol, and was more bio-available in the organs of broilers.     

The effect of vitamin E on growth performance and meat quality in broilers given diets containing distillers’ dried grain with solubles (DDGS)

1. The objective of the present study was to investigate the effect of vitamin E (VE, α-tocopherol acetate) on growth performance and meat quality of broilers fed on diets containing maize distillers’ dried grains with solubles (DDGS).

2. A total of 360 one-d-old broilers were randomly assigned to 6 groups. Each group comprised 6 replicates of 10 broilers. Broilers were allocated to 1 of 6 diets and fed for 49?d in a 3?×?2 factorial design. The dietary treatments included three concentrations of DDGS (0, 10 or 20%) and two concentrations of VE (0 or 200?mg/kg).

3. Diets containing 20% DDGS decreased the growth phase and average daily feed intake, demonstrating that small amounts of DDGS affected feed intake in broilers and that an excess of DDGS was not conducive to feed intake.

4. Different dietary concentrations of DDGS did not significantly improve colour, drip loss, cooking loss, or shear force. Supplementation with 200?mg/kg VE significantly reduced cooking loss and shear force and improved colour.

5. In conclusion, supplementation with DDGS at 10% and/or α-tocopherol acetate at 200?mg/kg had positive effects on growth performance and meat quality in broilers.     

Effects of inorganic and organic copper supplemented to first-calf cows on cow reproduction and calf health and performance

Two experiments were conducted to determine whether the supplementation of Cu in the organic or inorganic form to 2-yr-old cows, before and after calving, affects reproduction rate, calf health and performance, passive transfer of immunoglobulin, or liver and serum Cu concentrations compared with unsupplemented controls. Cows (n = 75 in 1997; n = 120 in 1998) were randomly assigned by estimated calving date and body condition score to one of three treatments: 1) Control, control; 2) Inorganic, inorganic Cu supplement (200 mg Cu from CuSO4); 3) Organic, organic Cu supplement (100 mg Cu from AvailaCu). In 1998, a fourth treatment was added; 4) CU-ZN, organic Cu and Zn (400 mg Zn from AvailaZn in the Organic diet). Cows were fed a hay-based diet and individually fed supplements for approximately 45 d before and 60 d after calving (approximately January 15 to May 15 each year). Liver biopsies were obtained from cows before supplementation began, and from cows and calves at 10 and 30 d after calving. Blood samples were obtained from both cows and calves at calving, and colostrum samples were collected for IgG and mineral content. Cow liver Cu concentrations before supplementation began were 58 mg/kg in 1997 and 40 mg/kg (DM basis) in 1998. By 10 d after calving, liver Cu concentrations of Control cows had decreased (P < 0.05) to 24 mg/kg (Cu deficient) in both years, whereas liver Cu concentrations of Cu-supplemented cows increased (P < 0.05) in both years. Calf liver Cu concentrations at 10 d of age were similar (P > 0.10) for all treatment groups. No differences (P > 0.10) were found in colostrum Cu concentrations, or in calf health among treatments. No differences (P > 0.10) were found in cow BW change, calf serum Cu concentrations, calf weaning weights, or in cow 60-d pregnancy rates among treatments in either year. In 1998, cows in the Organic group had higher (P < 0.05) 30-d pregnancy rate than Control cows. Neither serum samples nor placental tissue were reliable indicators of Cu status in cows. Feeding supplemental Cu (either inorganic, organic, or organic with extra Zn) to cows with liver Cu concentrations of approximately 50 mg/kg before calving did not improve cow 60-d pregnancy rates or the health and performance of their calves when compared with unsupplemented cows.     

Effects of dietary copper supplementation on production performance and plasma biochemical parameters in broiler chickens

1. A study was conducted to estimate the effect of copper (Cu) supplementation on growth performance and biochemical profiles of blood and meat in broiler chickens.

2. A total of 240?d-old broiler chicks (Vencobb-100) were randomly divided into 12 groups, each of 20 chicks (4 treatments?×?3 replicates).

3. The basal diet (T₁) contained 215?g?kg^?1 crude protein (CP), 12·76?MJ?kg^?1 ME, 32?g?kg^?1 total calcium and 5?g?kg^?1 total phosphorus. T_2, T₃ and T₄ were formulated to contain an additional 75, 150 and 250?mg?Cu?kg^?1 diet, respectively. Copper sulphate pentahydrate (CuSO₄, 5H₂O) was used as the source of Cu.

4. Significant reductions in plasma total cholesterol and triglyceride, and an elevated concentration of HDL-cholesterol, were observed in the chickens fed with 250?mg?Cu?kg^?1 (T₄) of feed at the 3rd and 6th week of the experiment. Total cholesterol in meat decreased significantly in the birds fed with dietary Cu at 250?mg?kg^?1 (T₄) of feed.

5. Growth performance was measured in terms of live weight gain, cumulative feed intake and feed conversion ratio at the end of d 21 and d 42 of the experiment, and the result was found to be commercially beneficial for the chickens receiving 150?mg?Cu?kg^?1 (T₃) of diet. The concentration of Cu in breast muscle and liver increased significantly at the end of experiment.

6. From this study it can be concluded that supplementation with dietary Cu may be beneficial for production performance and plasma biochemical characteristics of broiler chickens.     

Effect of amount and source of manganese and/or phytase supplementation on productive and reproductive performance and some physiological traits of dual purpose cross-bred hens in the tropics

1.?The effect of different amounts of added manganese (Mn) (0, 10, 20 and 40 mg/kg) in inorganic and organic form and phytase (0 and 300 U) was investigated on productive, reproductive and haematological traits on 480 hens and 60 cocks (Inchas breeds) divided into 12 groups: 10 and 20 Mn × 0 and 300 phytase × 2 Mn sources (8 groups), two negative controls (0 Mn × 2 levels of phytase) and two positive controls (40 Mn × 2 Mn sources).

2.?Phytase supplementation increased laying rate by 1·1% and egg weight by 0·4 g.

3.?Manganese supplementation at 10 mg/kg over dietary sources improved hatchability, at 20 mg/kg decreased death embryos and abnormality as those of hens supplemented with 40 mg/kg Mn. Inorganic Mn at 10 mg/kg significantly increased egg mass compared to the organic form. Inorganic Mn was more efficient in decreasing abnormal chicks than organic Mn. Phytase supplementation significantly increased hatchability of fertile eggs and decreased the number of abnormal chicks of groups fed on diets unsupplemented with Mn and those supplemented with 10 mg/kg Mn.

4.?Mn supplementation at 10 mg/kg over dietary sources significantly improved sperm mass motility and decreased abnormal sperm. Phytase significantly decreased lymphocyte cells and plasma AST.

5.?Mn supplementation of the control diet (containing only 16 mg/kg from raw materials) with 20 mg/kg of Mn from either organic or inorganic source is adequate to support egg production traits, egg quality, reproductive traits and economic efficiency of dual purpose cross-bred hens; however, phytase supplementation may reduce the required Mn supplementation to 10 mg/kg.     

凝结芽孢杆菌对蛋鸭产蛋性能、蛋品质及血清生化指标的影响

 试验旨在研究饲粮中添加不同水平凝结芽孢杆菌对蛋鸭产蛋性能、蛋品质及血清生化指标的影响。选取200日龄,产蛋率约80%的临武鸭240羽,随机分成4组,每组6个重复,每个重复10羽鸭,对照组饲喂基础饲粮,试验组在基础饲粮中分别添加100 mg/kg、150 mg/kg和200 mg/kg凝结芽孢杆菌,预试期7 d,正试期28 d。结果表明：（1）饲粮添加凝结芽孢杆菌可提高蛋鸭产蛋率、平均日产蛋量、平均蛋重和饲料转化率,但未达显著水平（P>0.05）;添加100 mg/kg和150 mg/kg凝结芽孢杆菌可显著降低产蛋鸭采食量（P<0.05）,添加200 mg/kg与各组间均无显著差异（P>0.05）;(2）饲粮添加凝结芽孢杆菌可显著降低鸭蛋蛋壳厚度（P<0.05）,当添加150 mg/kg和200 mg/kg时,差异达极显著水平（P<0.01）,凝结芽孢杆菌还可显著提高鸭蛋蛋黄颜色,蛋白高度和哈氏单位（P<0.05）;（3）芽孢杆菌对产蛋鸭血清中血糖、总蛋白、总胆固醇、甘油三脂等血清生化指标均无显著影响（P>0.05）。由此可知,饲粮中添加凝结芽孢杆菌能在一定程度上提高蛋鸭饲料转化率和产蛋性能,虽会引起蛋壳厚度降低,但不影响合格蛋率,还可提高蛋黄颜色和哈氏单位,对蛋品质有一定改善。综合考虑,蛋鸭饲粮中凝结芽孢杆菌的添加量以150 mg/kg较为适宜。     

Riboflavin requirements of white Pekin ducks from hatch to 21 d of age

1. A 2 × 8 factorial experiment containing different sexes (female and male) and 8 dietary riboflavin concentrations (1.2, 3.2, 5.2, 7.2, 9.2, 11.2, 13.2 and 15.2 mg/kg) was conducted to evaluate the riboflavin requirements of male and female White Pekin ducks from hatch to 21 d of age.

2. A total of 640 1-d-old Pekin ducks including 320 male and 320 female birds were randomly distributed into 80 wire-floor pens of 8 birds, sexed separately and with each treatment group containing 5 replicate pens. The birds were raised from hatch to 21 d of age. At 21 d of age, the weight gain, feed intake, feed conversion ratio and plasma and liver riboflavin were measured.

3. Growth depression, high mortality and low plasma and liver riboflavin were observed in riboflavin-deficient ducks, and these ill effects could be reduced by increasing dietary riboflavin concentrations. Weight gain, feed intake and riboflavin concentration in plasma and liver increased as dietary riboflavin increased.

4. According to broken-line regression analysis, the riboflavin requirements of modern breed of White Pekin ducks from hatch to 21 d of age for weight gain, feed conversion ratio, plasma riboflavin and liver riboflavin were 3.31, 5.20, 3.85 and 3.91 mg/kg for male and 3.27, 3.33, 3.84 and 3.28 mg/kg for female, respectively. Compared with female birds, more riboflavin was needed by male ducks, which may be because of significantly greater weight gain and liver riboflavin content of male ducks.     

Influence of dietary rapeseed oil, vitamin E, and copper on the performance and the antioxidative and oxidative status of pigs.

We investigated the effects of dietary copper and vitamin E in diets containing 6% rapeseed oil on the performance and the antioxidative and oxidative status of growing pigs. The 10 dietary treatments consisted of a basal diet (9 mg of vitamin E/kg feed, 15 mg of Cu/kg feed), the basal diet + 6% rapeseed oil (Diet 1; 18 mg of vitamin E/kg feed, 15 mg of Cu/kg feed), and Diet 1 plus supplements of vitamin E (0, 100, and 200 mg of dl-alpha-tocopheryl acetate/kg feed) and copper (0, 35, and 175 mg of Cu/ kg feed) in a 3 x 3 factorial arrangement of treatments. Eight or nine pigs were given ad libitum access to each diet from 25 to 100 kg of live weight. The inclusion of rapeseed oil tended (P < .10) to improve ADG and feed utilization. Compared with the addition of 35 mg of Cu/kg, the addition of 175 mg/kg improved growth rate and increased feed intake early in the experiment, but, over the total experiment, neither 35 nor 175 mg of Cu/kg affected performance. Compared with the addition of 100 mg of vitamin E/kg or no addition, the addition of 200 mg/kg reduced ADG over the total experiment (P = .05). The antioxidative and oxidative status of the pigs was evaluated in terms of blood and liver concentrations of antioxidants (alpha-tocopherol, ascorbic acid, vitamin A, superoxide dismutase, glutathione peroxidase), prooxidants (Cu), concentrations of lipids (triglycerides and cholesterol), fatty acid composition, thiobarbituric acid-reactive substances (TBARS), and clinical chemical (creatine kinase and glutamate-oxaloacetate-transaminase) and hematological variables that indicate the level of oxidative stress. There were no vitamin E deficiency signs or increased oxidative stress in pigs fed low dietary vitamin E levels, and no prooxidative effect of Cu was found. Increasing dietary levels of vitamin E increased the concentration of alpha-tocopherol in plasma and liver. Supplementation with Cu increased liver concentrations of Cu and alphatocopherol. The progression in liver TBARS was reduced by the addition of vitamin E and Cu. The addition of rapeseed oil changed the fatty acid composition of liver, increased alpha-tocopherol concentration in plasma and Cu concentration in liver, and reduced the rate of lipid oxidation in liver. In conclusion, even though the effects were minor, vitamin E, Cu, and rapeseed oil improved the antioxidative status of the live pigs.     

Effects of biotin on growth performance and foot pad dermatitis of starter White Pekin ducklings

1. An experiment with 9 dietary supplemental biotin concentrations (0, 0·03, 0·06, 0·09, 0·12, 0·15, 0·18, 0·21, 1·5?mg biotin/kg) was conducted to study the effects of supplementary dietary biotin on growth performance and foot pad dermatitis (FPD) of White Pekin ducklings from hatch to 21?d of age.

2. One-d-old male Pekin ducklings (n?=?576) were randomly divided into 9 dietary treatments, each containing 8 replicate pens with 8 birds per pen. Final weight, feed intake and body weight gain increased with increasing dietary biotin levels from hatch to 21?d of age. No differences were observed in feed conversion ratio.

3. The supplemental biotin requirement of ducklings for optimal body weight gain was estimated to be 0.180?mg/kg.

4. At 28?d of age, dehydration, cracks, bleeding and scab, and ulceration were observed in biotin-deficient ducks. The external scores for FPD decreased from 17·50 to 1·00 with increasing dietary biotin. It was concluded that supplemental dietary biotin should not be less than 0·21?mg/kg to minimise the incidence of FPD.     

植物甾醇对肉鸭胆固醇代谢和抗氧化性能的影响

2000只15日龄的商品代樱桃谷肉鸭随机分成5组,每组4个重复,每个重复100只肉鸭,分别饲喂添加0(对照组)、10、20、40、80mg/kg植物甾醇日粮。42日龄试验结束时,每组随机抽取公、母鸭各5只屠宰,测定各项指标。结果表明,植物甾醇对生产性能无显著影响(P>0.05)。植物甾醇降低了肉鸭血清中总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-C)的含量,当添加量为40mg/kg时差异显著(P<0.05);日粮中添加10mg/kg、20mg/kg和40mg/kg植物甾醇后,肉鸭肝脏胆固醇合成速度明显加快;添加80mg/kg植物甾醇的试验组肉鸭,血浆中总超氧化物歧化酶(T-SOD)活性显著(P<0.05)升高,添加10或40mg/kg植物甾醇的组,肝脏中T-SOD活性显著(P<0.05)升高。结果提示植物甾醇可能通过抑制低密度脂蛋白的生成来降低血脂,同时影响肝脏内源性胆固醇的合成,并且可能通过提高机体抗氧化酶活性达到抗氧化效果。     

Estimation of the relative bioavailability of inorganic copper sources for chicks using tissue uptake of copper

An experiment was conducted with 208 day-old male Cobb feather-sexed chicks to study tissue accumulation of Cu as an estimate of biological availability of inorganic Cu sources for chicks. Chicks were allotted randomly to dietary treatments that included an unsupplemented basal corn-soybean meal diet (11.1 mg/kg Cu, DM basis) or this basal diet supplemented with 150, 300 or 450 mg/kg Cu either as reagent-grade acetate or feed grade oxide, carbonate or sulfate. Chicks were housed in batteries and allowed ad libitum access to feed and tap water for 21 d. Liver Cu was not affected by dietary Cu from the oxide source, but it increased (P less than .001) with increasing dietary Cu from all other sources. Bone Cu was lower (P less than .05) in chicks fed 150 mg/kg Cu compared to other dietary levels of Cu but was not influenced (P greater than .10) by Cu source. Using the slope-ratio technique from regression of log liver Cu on mean daily Cu intake with Cu from acetate set at 100%, the relative biological availability values were estimated to be 88.5 and 54.3% for sulfate and carbonate, respectively, and oxide was essentially unavailable.     

The role of selenium in cadmium toxicity: interactions with essential and toxic elements

1. The study was part of a project designed to investigate if organic selenium (Se) can ameliorate the toxic effects of cadmium (Cd). The main objective of the present study was to investigate, in the chicken, the interactions between Se, Cd and the following elements: Sb, Ca, Cr, Co, Cu, Fe, Pb, Mg, Mn, Mo, Ni, V and Zn.

2. A total of 300 1-d-old chickens (broilers) were randomly distributed among 4 dietary treatments with 5 replicate pens per treatment. In T1, chickens were fed on a diet with 0·3?mg/kg added Se, without added Cd. In T2, chickens were fed on a diet with 0·3?mg/kg Se and 10?mg/kg Cd. In T3, chickens were fed on a diet with 0·3?mg/kg Se and 100?mg/kg of Cd added and in T4 treatment, chickens were fed on a diet with 3?mg/kg Se and 100?mg/kg Cd added. Se was added as Se-yeast. Cd was added as cadmium chloride (CdCl₂). On d 28 and 42, two chickens per replicate pen were killed for collection of whole blood, liver, kidney and breast muscle samples. Samples were analysed by ICP-MS. The data were analysed using a multivariate linear model.

3. While low Cd concentrations in the diet led only to an increase of Cd concentration in the examined tissues, addition of high concentrations of Cd increased the concentration of Cd, Cu, Sb and V and decreased that of Se, Mn and Fe. Addition of high Se concentrations did not significantly reduce Cd concentration.

4. Prior to model application, correlations of 78 elements were noted, while after model application 39 correlations were noted. Most notably, Cd was correlated with Ca, Co, Cu and Mg, while Se was correlated with Mn.

5. The present study revealed several correlations between essential, probably essential and toxic elements illustrating the importance of the balance between pro-oxidants and antioxidants.     

核黄素缺乏对1～28日龄北京鸭生长性能、器官指数和血浆生化指标的影响

本试验旨在研究核黄素缺乏对1~28日龄北京鸭生长性能、屠宰性能、器官指数、组织核黄素含量及血浆生化指标的影响。采用单因子完全随机试验设计,选取360只1日龄健康的雄性北京鸭,随机分为3个组,即核黄素缺乏组、采食配对组(人为控制该组采食量与核黄素缺乏组一致)和自由采食对照组,每组12个重复,每个重复10只鸭。核黄素缺乏组试验鸭饲喂核黄素缺乏饲粮(实测核黄素含量为1.38 mg/kg),采食配对组和自由采食对照组饲喂核黄素充足饲粮(在核黄素缺乏饲粮基础上添加10 mg/kg核黄素)。试验期为28 d。结果表明:与采食配对组和自由采食对照组相比,核黄素缺乏组试验鸭的平均日增重、胸肌率和腿肌率显著降低(P0.05),料重比和死亡率显著升高(P0.05),肝脏指数、心脏指数和胰腺指数显著提高(P0.05),血浆核黄素、肝脏核黄素和黄素单核苷酸含量显著降低(P0.05),血浆谷草转氨酶活性及总胆固醇和甘油三酯含量显著提高(P0.05)。由此得出,核黄素是北京鸭生长发育必需的营养素;饲粮中缺乏核黄素可降低1~28日龄北京鸭的生长性能和组织中核黄素含量,可提高肝脏指数并导致血浆总胆固醇和甘油三酯含量及谷草转氨酶活性升高。     

Effect of vitamins,probiotics and protein level on semen traits and seminal plasma biochemical parameters of post-moult male broiler breeders

1. A study was designed to investigate the comparative effect of supplementary vitamin E, vitamin C, probiotics and dietary crude protein concentration on semen traits and seminal plasma biochemical parameters in male broiler breeders after Zn-induced moulting.

2. A total of 180 male broiler breeders were induced to moult at 65 weeks of age by mixing ZnO in diet at the rate 3000?mg/kg of feed. After moulting, the males were divided into six groups that were given feed supplemented with: vitamin C (500?IU/kg), vitamin E (100?IU/kg), protein (140?g CP/kg), probiotics (50?mg/kg) and the combination of these components, while one group was kept as a control. Semen samples were collected weekly and semen volume, spermatozoa concentration, motility and dead spermatozoa percentage were determined. Seminal plasma was separated to determine the concentration of total antioxidant capacity (TAC), homocysteine, paraoxonase (PON1), arylesterase, ceruloplasmin, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities.

3. Semen volume was significantly higher in the vitamin E and C groups compared to the control. Spermatozoa motility was higher in the vitamin E group and dead spermatozoa percentage was significantly lower in the vitamin C group compared with the control group.

4. Seminal plasma TAC was higher in the vitamin E group, homocysteine was lower in the vitamin C and E groups. PON1 was higher in the combination group. Arylesterase increased significantly in the vitamin C and combination groups over time. Seminal plasma AST was significantly lower in the vitamin C and E supplemented groups whereas ALT decreased significantly only in the vitamin E group compared with the control. Higher concentrations of ceruloplasmin were observed in the combination group compared with the other treatments.

5. It was concluded that additional vitamin E and C or their combination was the most potent nutrient treatment for improving the semen traits and seminal plasma biochemical characteristics in male broiler breeders after Zn-induced moulting.     

饲粮核黄素水平对15～42日龄北京鸭生长性能和血浆生化指标的影响

本试验旨在研究饲粮核黄素水平对15~42日龄北京鸭生长性能和血浆生化指标的影响。采用单因子完全随机试验设计,选取288只体重相近的15日龄雄性北京鸭,随机分为6个组,每组6个重复,每个重复8只鸭。对照组饲喂基础饲粮(核黄素水平为1.38 mg/kg),试验组分别饲喂在基础饲粮中添加1.00、2.00、3.00、4.00和5.00 mg/kg核黄素的试验饲粮。试验期为28 d。结果表明,与对照组相比,饲粮中添加核黄素显著提高了15~42日龄北京鸭的平均日增重和平均日采食量(P0.05),显著提高了血浆核黄素含量(P0.05),显著降低了血浆谷丙转氨酶活性和甘油三酯含量(P0.05)。由此可见,饲粮中添加核黄素可显著提高15~42日龄雄性北京鸭的生长性能和血浆核黄素含量。以平均日增重、平均日采食量、料重比和血浆核黄素含量为评价指标,采用折线模型估测15~42日龄雄性北京鸭核黄素需要量为2.24~2.66 mg/kg。     

Effect of copper source and level on performance and copper status of cattle consuming molasses-based supplements

Two studies were conducted to evaluate the availability of dietary Cu offered to growing beef cattle consuming molasses-based supplements. In Exp. 1, 24 Braford heifers were assigned randomly to bahiagrass (Paspalum notatum) pastures (two heifers/pasture). Heifers were provided 1.5 kg of TDN and 0.3 kg of supplemental CP/heifer daily using a molasses-cottonseed meal slurry. Three treatments were randomly assigned to pastures (four pastures/treatment), providing 100 mg of supplemental Cu daily in the form of either CuSO4 (inorganic Cu) or organic-Cu. A third treatment offered no supplemental Cu (negative control). Heifer BW was collected at the start and end of the study. Jugular blood and liver samples were collected on d 0, 29, 56, and 84. In Exp. 2, 24 Brahman-crossbred steers were fed the same molasses-cottonseed meal supplement at the same rates used in Exp. 1. Steers were housed in individual pens (15 m2) with free-choice access to stargrass (Cynodon spp.) hay. Four Cu treatments were assigned to individual steers (six pens/treatment) providing 1) 10 ppm of Cu from an organic source; 2) 10 ppm Cu from Tri-basic Cu chloride (TBCC); 3) 30 ppm of Cu from TBCC; or 4) 30 ppm of Cu, a 50:50 ratio of TBCC and organic Cu. Body weights and jugular blood and liver samples were collected on d 0, 24, 48, and 72. In Exp. 1, liver Cu concentrations did not differ between heifers supplemented with inorganic and organic Cu. Each source resulted in increased (P < 0.05) liver Cu concentrations compared with the unsupplemented control. Plasma ceruloplasmin concentrations were higher (P < 0.05) for Cu-supplemented heifers, independent of Cu source. Heifer ADG tended (P = 0.11) to increase with Cu supplementation compared with the unsupplemented control. In Exp. 2, liver Cu was greater (P < 0.05) on d 24, 48, and 72 for steers consuming 30 vs. 10 ppm of Cu. Steers supplemented with organic Cu had lower DMI than steers supplemented with 10 or 30 ppm of TBCC. These data suggest that the inorganic and organic Cu sources evaluated in these studies were of similar availability when offered in molasses supplements. A dietary Cu concentration greater than 10 ppm might be necessary to ensure absorption in beef cattle fed molasses-based supplements.     

Copper, zinc and manganese concentrations in equine liver, kidney and plasma

Five groups of horses were fed different diets of known trace mineral concentration for a minimum of six months. Copper (Cu), zinc (Zn) and manganese (Mn) concentrations were measured in livers of 125 yearling horses and kidneys of 81 yearling horses as an assessment of trace mineral status. Plasma Cu and Zn determinations were made for all horses.

Mean hepatic Cu concentrations of horses fed diets containing 6.9 to 15.2 mg Cu/kg dry matter (DM) feed were 0.27 to 0.33 μmol/g DM tissue. Plasma Cu concentrations ranged between 22.8 to 28.3 μmol/L. There was no simple mathematical relationship between plasma and hepatic Cu concentrations. Mean hepatic Zn concentrations in horses fed diets containing 25.6 to 52.2 mg Zn/kg DM feed were determined to be between 2.75 to 2.91 μmol/g DM tissue. Mean plasma Zn concentrations in groups of horses were between 11.7 to 13.5 μmol/L. Plasma Zn concentrations were not indicative of hepatic Zn concentration. Hepatic Mn concentrations ranged between 0.13 and 0.14 μmol/g DM tissue.

Renal Zn concentrations ranged between 1.55 to 1.63 μmol/g DM tissue and did not differ with diet. Mean renal Mn concentrations were 0.09 μmol/g DM tissue for all groups of horses. Renal Cu concentrations ranged from 0.36 to 0.47 μmol/g DM tissue and differed with diet.

     

Effect of dietary supplementation of thymol,synbiotic and their combination on performance,egg quality and serum metabolic profile of Hy-Line Brown hens

1. An experiment was conducted to determine the effects of dietary supplementation of thymol, synbiotic (Biomin, IMBO) and their combination in laying hen diets on laying performance, egg quality and serum metabolic profile from 24 to 36 weeks of age.

2. Treatment groups were fed on a control diet, the control diet supplemented with thymol (250 mg/kg), the control diet supplemented with synbiotic (250 mg/kg) or the control diet supplemented with a combination of thymol (250 mg/kg) and synbiotic (250 mg/kg).

3. Supplementation of thymol and synbiotic, separately as well as combined, improved egg weight, egg production, egg mass and feed conversion ratio from 24 to 36 weeks of age. The eggs obtained from thymol, synbiotic or their combination treatments displayed higher values of shell thickness, Haugh unit and shell percentage compared to the control.

4. Serum cholesterol significantly decreased in the single or combined form of thymol and synbiotic supplementation treatments.

     

Estimation of the relative bioavailability of copper sources in chicks fed on conventional dietary amounts

1. Tissue accumulation of Cu from dietary additions of 0, 5, 10, or 20 mg/kg Cu as reagent grade Cu acetate and feed grade Cu carbonate was determined in day‐old chicks fed on conventional maize‐soyabean meal starter diets (5.41 mg/kg Cu as‐fed basis) for 3 weeks.

2. Average daily food intake, daily weight gain and food conversion were similar among treatments.

3. There were linear increases in plasma and liver Cu concentrations (P< 0.01) as dietary Cu increased.

4. Bioavailability of Cu as carbonate was 0.66 that of Cu in the acetate based on the multiple regression slope ratio of liver Cu concentration on added dietary Cu. Although responses for the two Cu sources did not differ significantly, the relative bioavailability of the Cu carbonate was similar (0.66 vs 0.68) to that obtained in an earlier study (Ledoux et al., 1991) with greater dietary Cu contents (150, 300 and 450 mg/kg) in which the slopes of the equations representing the two sources differed (P<0.05).