蛋鸡的能量和蛋白质营养研究进展

随着家禽品种选育不断取得新进展，蛋鸡的生产性能也得到极大提高，76周龄鸡的产蛋量已由过去的15.5～17.0 kg提高到现在的17.5～19.5 kg。这就是说，蛋鸡的新陈代谢强度在不断提高，其基础代谢、维持需要和生产需要也随着品种选育不断进步而变化。因此，不断研究蛋鸡的营养需要量，科学配制日粮对于充分发挥蛋鸡的遗传潜力，提高蛋鸡的生产性能有重要意义。本文将对国内外学者近十年来在蛋鸡的能量、蛋白质和氨基酸营养研究方面所取得的成果进行综述。1 能量1.1 蛋鸡的能量需要量和数学预测模型 近十年来，国内外学者在鸡的能量需要量方面…     

鹅能量蛋白质营养研究进展

能量、蛋白质是动物营养研究的关键,本文综述了鹅的能量、蛋白质(氨基酸)营养研究进展,以期促进其在鹅生产中的应用,推动养鹅业发展。     

肉鸭能量与蛋白质营养研究进展

<正>我国养鸭业历史悠久,早在公元前500年前后己经有大群养鸭的记载,而现代肉鸭业的兴起与发展,只是近二十几年的事情。据FAO公布统计数据,2006年我国鸭饲养量达23.6亿只,占世界的75.4%;鸭肉产量达235万吨,占世界鸭肉总产量     

肉鸡能量和蛋白质的维持需要量

据日本东北大学农学系报道,随着肉鸡的生长速度逐年上升,其能量、蛋白质的积蓄速度也随之增大。肉鸡的营养利用性和体内营养成分积蓄,是随能量和蛋白质的维持需要量的变化而变化的。而且,每一代谢体重的维持需要量是不一致的,随生长而变动。对2～8周龄的肉鸡,适当限制喂料进行试验,测定体能量和体成分积蓄量以及维持所需要的蛋白质量。试验结果表明,随饲料摄取量减少,体增重呈直线减少,其减少的比例随生长而加大。但在体组织成分上,体蛋白质含量在限     

母猪的能量和蛋白质营养

母猪生产性能对整个养猪生产及效益关系重大.母猪繁殖周期的各阶段是相互联系的统一体,某一阶段的营养能影响继后阶段及更后时期的生产性能.近年来,国外对母猪各阶段的营养需要及营养对繁殖的影响进行了大量的研究,现将母猪的能量和蛋白质营养研究的一些最近进展作一简要综述.1 妊娠期     

丁酸钠可以提高肉鸡能量和蛋白质消化率

最近在印度进行的一次试验评价了对照日粮及在日粮中添加0.5kg/吨和1kg/吨（分别为1和2组）两种水平丁酸钠（GustorB-92）对生产参数以及日粮能量和蛋白质消化率的影响。此外,在21和42天时采集回肠样品评估了肠绒毛的长度和宽度。     

繁殖母猪的能量和蛋白质营养

前言 　　研究报道表明,母猪的利用年限与其生产率在逻辑上呈正相关,其利用年限及其有关的问题(返情率,受胎率)一方面取决于母猪的整个繁殖周期中躯体组成变化的特点,更重要的是取决于泌乳期间母猪瘦肉和(或)脂肪组织的减少量(King,1987;Whittemore和Morgan,1990).为达到最高繁殖性能的最佳饲养方案,是使母猪躯体成分在繁殖周期任何阶段的变化减少到最低限度(Dourmad等,1994).这样的方案要求有充足的饲料供应以满足整个繁殖周期母猪营养需要.本文目的在于对妊娠及泌乳母猪的能量与蛋白质营养方面作一综述,同时提供一些在实际条件下预测营养需要量的原则,本文将讨论使用析因法进行预测.本文还将探讨气候环境(如环境温度)对泌乳母猪的能量需要量,尤其是对采食量的影响.……     

肉鸡营养研究进展

过去,在日粮中添加不同水平的氨基酸,以最大生长反应作为评定指标确定了肉鸡的氨基酸需要量。尽管这种方法存在不足（Ｇｏｕｓ等,１９８５）,但仍为营养学家广泛采用,用它能制定出各种营养素的需要量,而且能够配制出最低成本的饲料。然而想用它来进行精确的成本—效...     

肉鸡能量需要量预测模型的研究进展

能量摄入对肉鸡的生长具有重要作用。肉鸡能量代谢受多种因素的影响,如性别、环境温度、活重、采食量等。建立肉鸡能量需要模型,对于改善饲料效率,提高经济效益具有重要的作用。本文就肉鸡能量需要预测模型的重要性、不同模型的比较及存在的问题和发展方向四方面进行综述。     

饲粮能量、蛋白质水平对肉鸡肉质的影响

近年来 ,随着肉鸡业中对生长速率和饲料效率的遗传选育 ,肉鸡的生长速度提高了两倍多 ,料肉比达 2∶1。但伴随着生长率的不断提高 ,肉鸡肉质变得粗老 ,缺少风味 ,腹脂沉积增多 ,降低了消费者对肉鸡肉质的满意度 ,也给屠宰加工业增加了除去脂肪的麻烦。生长率不仅受遗传因素的影响 ,还受能量、蛋白质水平 (以下简称能蛋水平 )的影响 (Ｃｈｅｒｒｙ ,1 978;Ｍａｒｏｈ ,1 977)。本文综述了饲粮能蛋水平对肉鸡肉质的影响。1　能蛋水平对肉鸡肉质的影响1 1　直接影响　饲粮能蛋水平影响肉鸡腹脂沉积 ,直接影响肉质。许多研究表明 ,影响脂肪沉积…     

肉用仔鸡能量、蛋白质及氨基酸营养研究的进展

近几年来,国外学者从营养的角度就肉用仔鸡对能量的利用、氨基酸需要量方面做了大量的研究,该文简要综述了影响肉用仔鸡能量利用的日粮因素和肉用仔鸡的氨基酸需要量及氨基酸理想模式的研究进展。     

Effect of dietary energy restriction on retention of protein,fat and energy in broiler chickens

1. Broiler chickens were fed 60–100% of recommended energy intakes to study the effects of energy restriction on protein and fat retention.

2. At an energy retention of 179 kJ/kg W ^0·75 d, only protein was retained. At higher energy intakes, each increment in retention had a rather constant composition: about 85% energy in fat and 15% in protein. At lower energy intakes body fat was mobilised whereas protein was deposited.

3. The efficiencies of energy retention in protein and fat were estimated to be 0·66 and 0·86 respectively.

4. The rather constant composition of additional retained energy after additional energy supply provides an explanation for a linear relationship between energy intake and energy retention.     

Effects of chitosan on growth performance and energy and protein utilisation in broiler chickens

1. Two experiments were conducted to investigate the effects of dietary chitosan on growth performance, energy availability and protein retention in broilers. 2. Experiment 1 was a 42-d growth assay, in which 294 1-d-old male broilers were given one of 7 dietary treatments. A control feed was supplemented with 5 levels of chitosan (0.2, 0.5, 1.0, 3.0 and 5.0 g/kg) or 50 mg/kg chlortetracycline (CTC). 3. Increasing chitosan inclusion gave a nonlinear increase (P< 0.001) in feed conversion efficiency (FCE). Optimal growth and feed conversion were obtained with 0.5-1.0 g/kg chitosan. 4. In experiment 2, 42 1-d-old male broilers (6/treatment) were individually housed but fed on the same diets as in experiment 1. Excreta were collected from d 19-21 and d 40-42. 5. The addition of 0.5-1.0 g/kg chitosan increased nitrogen retention compared with the control group (P< 0.01), while apparent metabolisable energy in the diets was not altered.     

The response of growing broiler chickens to dietary contents of protein,energy And Added Fat

1. The results of 47 experiments with broilers over the period 1974 to 1983 were selected for regression analysis. Included were those dealing with the relationship of growth and food utilisation to content of dietary protein (DP), metabolisable energy (DME) and added fat (DAF) in conventional feedingstuffs.

2. Significant correlations were found between DP and DME (0#lb50; P < 0#lb01), DP and DAF (0#lb61; P < 0#lb01), and DME and DAF (0#lb65; P < 0#lb01) contents.

3. Using multiple regression models, growth and food utilisation efficiency (FUE) were found to be dependent on the linear and quadratic effects of DME (r² values = 0#lb67 and 0–64 respectively). Growth and FUE were also dependent on the linear and quadratic effects of DP (r² values = 0#lb70 and 0#lb49 respectively).

4. By including the effects of DME, DP and DAF in the gain and FUE models it was shown that growth and FUE were dependent on DME, DP and DAF (r² values = 0#lb76 and 0#lb79 respectively).

5. It was concluded that hypotheses concerning the broiler's response to DME and DAF were both correct but incomplete. DME, DP and DAF contents must all be known to predict accurately growth and FUE.     

The effect of dietary energy:protein ratio,protein quality and food allocation on the efficiency of utilisation of protein by broiler chickens

1. Various theories have been proposed to explain the reduced performance of broilers when given feeds excessively high in protein, but a satisfactory solution to this problem had, up to now, not been found. Three experiments were conducted to test the hypothesis that the efficiency of utilisation of protein (e_p) is a linear–plateau function of the ratio between the feed apparent metabolisable energy and digestible crude protein contents (AMEn:DCP) and that dietary protein quality, feed allocation and sex do not influence this relationship.

2. A ‘linear–plateau’ model successfully described the efficiency of protein utilisation (e_p) as a function of AMEn:DCP in all three experiments. In Experiment 1, with both sexes being both ad libitum and control fed, the breakpoint was at 58.6 MJ AMEn/kg DCP. In Experiment 2, both sexes were fed balanced and unbalanced protein series, and at different rates, the slopes of the ascending part of the linear–plateau relationships for the different treatments were the same for all treatments (0.0204), and the inflection point was at 71 MJ AMEn/kg DCP. Using similar treatments in Experiment 3, the breakpoint for the balanced protein was 72 MJ/kg and for the unbalanced, 64, with a combined slope of 68 MJ AMEn/kg DCP.

3. The three experiments provide adequate evidence that e_p is a linear–plateau function of the dietary AMEn:DCP ratio with a breakpoint of around 66.2 ± 1.98 MJ AMEn/kg DCP. Below this critical ratio, food intake declines as does protein and lipid retention.

4. That broilers, like pigs, exhibit an energy-dependent phase when high-protein feeds are offered is of practical importance when formulating pre-starter feeds for broilers and starter feeds for turkey poults as the e_p of such feeds may well fall below the maximum due to the lack of dietary energy required to process the high dietary protein contained in such feeds resulting in poorer performance than expected.     

The energy and protein concentration of broiler rations in Cuba. 3. Male broilers in the summer

A total of 1,900 male broilers of the variety White Plymouth Rock was tested with 4 energy concentrations (10.5, 11.5, 12.6 and 13.6 MJ metabolizable energy/kg) and 4 protein concentrations (15.0, 17.5, 20.0 and 22.5% CP) in their first 56 days of life in 16 test groups. The animals were kept in cages and were directly exposed to the natural Cuban summer temperatures from their 15th day of life onwards. As every test group was run with 6 repetitions, the results could be variance analytically calculated. In a comparison of the behaviour of the male animals in winter and in summer it can be stated that the animals took in between 3.4 and 25% more feed in winter than in summer. In general, a lower body protein and body fat amount could be found in all test groups in summer compared to that in winter. Feed expenditure and the utilization of energy and protein were not as good as in winter. It could be shown that both maximum live weight and live weight gain can be achieved in the 2nd fattening period in the Cuban summer if rations containing 12.6 MJ metabolizable energy and 20% CP are fed in a one-phase feeding system.     

The response of male broiler chickens to diets with various protein and energy contents during the growing phase

1. In two trials each using 2 400 male broilers, the regression of body weight on the linear effects of dietary protein, energy and age, the quadratic effect of age, and their interactions, accounted for approximately 99% of the observed variation during the growing and finishing period (3 to 8 weeks of age). Increasing either dietary protein or energy content significantly increased body weight.

2. The regression of food consumption on the linear effects of age, protein, energy and protein × energy interaction, and the quadratic effect of age accounted for 94% of the observed variation. The regression of food utilisation on the linear effects of protein, energy, and age and the quadratic effects of dietary protein and age accounted for 97% of the observed variation. Food consumption and efficiency were dependent on both dietary protein and energy, increasing with increases in either dietary protein or energy content.

3. The regression of fat in the dressed carcass on the linear effects of protein, energy and age accounted for 19% of the observed variation. Carcass fat increased with increasing age and dietary energy, and decreased with increasing dietary protein.

4. Although body weight, food consumption and utilisation were significantly different between trials, the proportion of carcass fat was not.     

Performance and economic evaluation of feeding programs varying in energy and protein densities for broiler grillers

A study was conducted to evaluate field performance and economic impacts of feeding diets varying in AME and amino acid (AA) densities to Cobb 500 female broiler grillers (eviscerated carcass averaging 1.0 kg). Corn–soy diets were fed to birds in a factorial arrangement of 3 AME (low, moderate, and high) by 3 AA densities (low, moderate, and high). Differences in AA and AME average values were of 10 and 1.5%, respectively. Treatments had 8 replications of 40 birds allocated in floor pens. Live performance was significantly improved in parallel with increases in AME and AA; however, carcass yield increased and abdominal fat was reduced only when AA was increased (P < 0.05). Gross margins (GM) for each treatment were calculated using scenarios of high and low market costs for corn, soybean meal, as well as for carcass prices. Costs were classified as variable [costs of feeding (CF), fixed farm costs (FFC), and fixed processing costs (FPC)] and their behavior in response to nutritional density was studied. All cost components, (CF, FFC, and FPC) decreased as AME increased, which resulted in the lowest total costs (TC) for the highest AME diets in all scenarios tested, as well as the greatest GM for those dietary programs. In contrast to AME, cost components moved in opposite directions in response to AA density whereby, in 4 out of 7 scenarios, optimizing CF did not result in greater GM. The present study was conducted with low-weight carcasses and, therefore, conclusions made from the presented data are restricted to this type of product. It is concluded that when broiler grillers are objects of study, the use of CF as the sole criteria to choose an optimal feeding program, without considering significant fixed costs present along the production and meat processing chains, tends to underestimate the economic potential of increasing nutrient density.