Optimal in‐feed amino acid ratio for broiler breeder hens based on deletion studies

An ideal amino acid ratio (IAAR) for breeder hens is needed for maximum nitrogen retention (NR) taking into account nitrogen deposition in body (ND_B), feathers (ND_F) and egg mass (NEM) to improve dietary protein efficiency. Thus, the aim of this study was to apply the deletion method to derive the IAAR for broiler breeder hens. The nitrogen balance trials were performed from 31 to 35 weeks and from 46 to 50 weeks. Twelve treatments with eight replicates and one hen per cage were used. A balanced diet (BD) was formulated to meet the requirement of all nutrients. The other diets were formulated diluting 55% of BD with corn starch and refilled with amino acids (AAs) and other ingredients, except the AA tested. Each trial lasted 25 days. Feather losses, egg production and egg weight were recorded daily, and the samples were stored to further determine NEM and nitrogen in feather losses (ND_FL). At the start and the end of each period, a group of birds were slaughtered to further determine ND_B and ND_F. The NR was calculated as the sum of ND_B, ND_F, ND_FL, NEM and the nitrogen maintenance requirement (NMR). The deletion of valine greatly depressed the NR in peak production (31 to 35 weeks) while the deletion of the isoleucine greatly depressed the NR of the hens from 46 to 50 weeks of age. The percentual reduction in NR and the per cent of the AA to delete from the BD were used to calculate the AA requirement. The average IAAR was Lys 100, Met+Cys 86, Trp 23, Thr 80, Arg 113, Val 90, Ile 91, Leu 133, Phe+Tyr 108, Gly+Ser 94 and His 35. The IAAR was in line with the recommendation from the literature, validating deletion method with the advantages from a rapid and low‐cost procedure.     

关于预混料生产的几点看法

由一种或多种饲料添加剂与载体或稀释剂按一定比例配制的均匀混合物叫添加剂预混料，简称预混料。添加剂预混料的种类很多，按原料种类分类有:1.由单一原料制成的预混料，如维生素A预混料、硒预混料等；2.由同类原料组成的预混料，如复合维生素预混料、微量元素预混料；3.由不同原料组成的预混料，由二类或多类添加剂组成，如由维生素、微量元素、氨基酸、抗生素、防霉剂等组成的预混料，又叫复合添加剂预混料。随着配合饲料工业的发展，饲料添加剂工业迅速兴起，全世界批准使用的添加剂品种达数百种，每个品种又有多种规格，复合预混料的…     

Sulphur amino acid requirement of laying hens and the effects of excess dietary methionine on laying performance

1. Individually‐caged laying hens were fed on maize‐soya bean meal diets containing 11.50 or 12.35 MJ ME/kg with sulphur amino acid (SAA) contents varying from 5.0 to 7.0 g/kg in period 1 (0 to 20 weeks); from 5.0 to 8.0 g/kg in period 2 (21 to 36 weeks) and from 5.0 to 10.0 g/kg in period 3 (37 to 52 weeks).

2. A SAA requirement of about 750 mg/hen d, of which about 425 mg was methionine, was found to be adequate for birds producing on average 51 g egg mass per hen d over 52 weeks. The SAA requirement was found to be higher for maximum efficiency of food utilisation than for maximum egg yield.

3. A diet containing 140 g protein/kg adequately supplemented with methionine and lysine, could sustain laying performance almost identical to that achieved on a diet containing 167 g protein/kg.

4. In diets with 140 g protein/kg the addition of 0.5 to 3.5 g dl‐methionine/kg diet in excess of the requirement did not affect egg production adversely, but food conversion efficiency was decreased.     

微生物发酵饲料在蛋鸡生产中的应用研究

选择42周龄海兰褐蛋鸡480只,随机分为4组,每组设5个重复,每组重复24只鸡。对照组(I组)饲喂基础日粮;试验Ⅱ、Ⅲ、Ⅳ组分别在每100 kg基础日粮中添加微生物发酵饲料5、10、15 kg。预试期14 d,正试期42 d。结果表明:(1)与对照组相比,Ⅱ、Ⅲ组产蛋率显著提高(P<0.05),Ⅲ组料蛋比显著降低(P<0.05);各试验组采食量、蛋重差异均不显著(P>0.05)。(2)Ⅲ组蛋壳强度较对照组显著提高(P<0.05);Ⅲ、Ⅳ组哈氏单位较对照组显著提高(P<0.05);各试验组蛋黄颜色均有极显著提高(P<0.01)。(3)Ⅲ、Ⅳ组血清钙、谷草转氨酶较对照组显著提高(P<0.05),Ⅲ组GPT较对照组显著提高(P<0.05)。由此可见,本试验条件下,每100 kg蛋鸡基础日粮中添加10 kg微生物发酵饲料可以显著提高蛋鸡的生产性能与经济效益。     

Overall welfare assessment of laying hens: Comparing science‐based,environment‐based and animal‐based assessments

To increase the validity of evaluations and facilitate expansion and maintenance of assessment systems, we constructed a database of studies on the welfare of laying hens around the world. On the basis of this database, we devised a science‐based welfare assessment model. Our model includes measurements, levels and weightings based on the scientific studies in the database, and can clarify the advantages and disadvantages of housing systems for laying hens from the viewpoint of the five freedoms. We also evaluated the usefulness of our model by comparing it with environment‐based Animal Needs Index (ANI), another science‐based model called FOWEL, and animal‐based measurements. Our model showed that freedom from injury, pain and disease, and freedom from discomfort were more secure in the cage system, while non‐cage systems scored better for natural behavior and freedom from fear and distress. A significant strong‐positive correlation was found between the animal‐based assessment and the total scores of ANI (rs = 0.94, P < 0.05), FOWEL (rs = 0.99, P < 0.05) or our model (rs = 0.99, P < 0.05), which indicate that these different approaches to welfare assessment may be used almost interchangeably to ‘measure’ a common property (‘overall laying hen welfare’). However, assessments using our model and FOWEL were more sensitive than ANI and can be applied to cage systems, which suggest that our model and FOWEL may have added value.     

Variability of amino acid digestibility of lupin and pea grains in caecectomised laying hens

1. The objective of this study was to investigate the variations in amino acid (AA) digestibility of lupin and pea grains in caecectomised laying hens. The relationship between AA digestibility and chemical constituents of the grains was determined.

2. Twelve variants of lupins and peas were each added to a basal diet at a concentration of 300 g/kg, at the expense of maize starch. The lupin and pea variants were separately investigated in two subsequent trials. Each trial consisted of two 7 × 7 Latin squares, each comprising the basal diet and six diets with lupins or peas.

3. Fourteen caecectomised laying hens (LSL-classic) were individually housed in metabolism cages and 120 g/d of experimental diets were provided for eight days. During the last four days, excreta were collected quantitatively and feed intake was recorded. A regression approach was used to determine the AA digestibility of the lupin and pea variants.

4. Amino acid digestibility of the lupins and peas was high, although significant differences in AA digestibility among the lupins and peas were detected. The digestibility of lysine was in the range of 0.87–0.91 and 0.87–0.93 for lupins and peas, respectively. The digestibility of methionine in lupins and peas varied between 0.80–0.88 and 0.72–0.90. Variations in AA digestibility in peas were more pronounced than in lupins.

5. Significant correlations between chemical constituents of lupins, such as alkaloids, and AA digestibility were detected in some cases, without a consistent pattern. In peas, tannin concentration and the insoluble protein fraction were negatively correlated with digestibility of some AAs, but only when one colour flower variant was considered. Trypsin inhibitor activity in peas was negatively correlated with AA digestibility, particularly for the white flower variants.     

Use of encapsulated L-lysine-HCl and DL-methionine improves postprandial amino acid balance in laying hens

The supplementation of dietary limiting amino acids (AA) with crystalline AA makes the use of low-protein diets an option in poultry production. The differing absorption rates of crystalline and protein-bound AA may lead to temporally imbalanced AA in the postabsorptive period. In this study, two experiments were conducted to evaluate the effect of encapsulated L-lysine-HCl (L-Lys-HCl) and DL-methionine (DL-Met) on the laying performance of hens. In exp. 1, a total of 135 forty-seven-wk-old Hy-Line Brown hens were subjected to three dietary treatments for 8 wk: basal diet supplemented with 0.14% L-Lys-HCl and 0.17% DL-Met to satisfy the NRC (1994) total Lys and Met recommendation (control) and basal diet supplemented with encapsulated L-Lys-HCl and DL-Met at the levels of 60% (60CLM, 0.084% L-Lys-HCl and 0.102% DL-Met) or 80% of control (80CLM, 0.112% L-Lys-HCl and 0.136% DL-Met), respectively. In exp. 2, 24 fifty-five-wk-old Hy-Line Brown hens were individually reared in cages and subjected to the same treatments as in exp. 1. The plasma concentrations of free AA and nitrogen metabolites were measured 2, 4, and 6 h after fed. The results showed that dietary AA treatment had no significant influence on body weight (BW), feed intake, laying rate, egg weight, egg mass, or feed efficiency. The expression levels of AA transporters CAT-1, y⁺LAT1, b^0,+AT, B⁰AT, rBAT, EAAT3, and PepT1 in the duodenum, jejunum, and ileum were not influenced (P > 0.05) by dietary treatment. There was an interaction of dietary AA treatment and time (P < 0.05) and the 80CLM hens exhibited higher concentrations of Lys (P < 0.05) than the controls at 2-h time point. In contrast, plasma Met concentration was not influenced (P > 0.05), while Cys was reduced in the 60CLM hens at every time point. The 80CLM hens had higher taurine concentrations than those receiving the control diet at every postprandial time point. In conclusion, these findings demonstrate that by using encapsulated form, the supplemental levels of synthetic L-Lys-HCl and DL-Met can be effectively reduced by approximately 20% with no negative effect on laying performance. The result suggests that encapsulated Lys and Met may ameliorate the postabsorptive AA balance and contribute to the reduced dietary AA supplemental levels.     

The effect of 2,4-dichlorophenoxyacetic acid on laying hens

Laying hens were fed 2,4‐D, a herbicide, at a rate equivalent to 50 and 150 mg/kg diet from age 28 to 48 weeks. No adverse effects of the treatments were observed upon rate of egg production, egg or yolk weight, egg shell thickness, hatchability or growth rate of the progeny.     

饲料中添加海藻粉对蛋品质的影响

近年来,随着养殖业的快速发展,饲料资源呈现出相对缺乏的趋势,尤其是蛋白质饲料缺乏成为比较突出的问题。人口的急剧增长、耕地的大量减少,动物与人争粮的矛盾更加严重,开发新的饲料原料成为畜牧市场的需求亮点。我国海域辽阔,藻类资源异常丰富,如海带、马尾藻、紫菜、浒苔等,这些海藻含有陆地植物无可比拟的微量元素、维生素、     

A model for the description and prediction of the response of laying hens to amino acid intake

A model which describes the response of groups of laying hens to different levels of amino acid intake is presented. The model is based on the assumption of simple linear relationships between amino acid intake and the output characteristics, egg production and maintenance, for individual birds. The response for a group of birds is then derived as the average of the individual responses. The shape of this flock—response curve depends on seven parameters, namely the mean maximum egg output (ē _max), variation in E _max, mean body weight (W), variation in W, the correlation between egg output and body weight, and two constants (a and b) representing respectively the quantities of amino acid required for unit egg output and for maintenance of unit body weight.

Three methods of manipulating the model are described. These use (i) a computer simulation procedure; (ii) the exact solution for the model and (iii) some reasonable approximations for practical application.

The use of the model for describing experimental data and for predicting amino acid requirements is discussed, and the main limiting assumptions and some possible extensions of the principles involved are pointed out.     

海藻饲料添加剂对蛋鸡产蛋性能、血清抗氧化性及生长的影响

试验研究了在蛋鸡饲粮中添加不同剂量的海藻饲料添加剂对蛋鸡产蛋性能、血清抗氧化性、生长及营养物质消化率等的影响。选取360只26周龄体重相近的海兰褐蛋鸡,随机分为6组(每组3个重复,每个重复20只鸡),1组为空白对照组,饲喂基础饲粮;2组为抗生素对照组,在基础饲粮中添加0.005%的杆菌肽锌;3~6组为试验组,分别在基础饲粮中添加0.02%、0.04%、0.06%、0.08%的菊粉,0.025%、0.050%、0.100%、0.150%的大西洋海藻粉及相同剂量的铜藻粉(以下简称低、中、较高、高剂量海藻复合物),预试期7 d,正式试验期63 d。结果表明:海藻饲料添加剂对蛋鸡的产蛋性能有明显的剂量-效应关系,添加量为中等剂量海藻复合物(4组)时最佳且差异显著(P<0.05)。此添加量下,蛋鸡血清中超氧化物歧化酶活性最高(P<0.05)。试验中粗纤维的表观消化率随添加剂量的增加而增加(P<0.05)。低剂量试验组体重增长最多且差异显著(P<0.05)。试验结果表明,基础饲粮中添加中剂量海藻复合物作为蛋鸡饲料添加剂,能够显著提升蛋鸡产蛋性能及血清抗氧化性。     

Hydrolysed feather protein as a source of amino acids for laying hens

1. The value of hydrolysed feather protein (HFM), included at 70 g/kg in a wheat‐based diet, as an amino acid source for laying hens was determined.

2. Egg production was reduced in hens fed on diets containing HFM owing to a deficiency in lysine, methionine and tryptophan.

3. Supplementation of the diet containing HFM with 3'0 g lysine (as L‐lysine HC1), 0.7g DL‐methionine and 0.5g L‐tryptophan per kilogram, resulted in a daily egg mass output similar to that achieved with a conventional layers’ diet.     

棉粕源复合发酵饲料对产蛋鸡生产性能的影响

试验选用1 152只50周龄左右的海兰褐健康蛋鸡随机分成4组,每组设3个重复,每个重复96只鸡,研究棉粕源发酵饲料对产蛋鸡生产性能的影响。第Ⅰ组为对照组,饲喂基础日粮;第Ⅱ、Ⅲ、Ⅳ组在基础日粮营养水平基本一致的基础上分别添加5%、10%、15%的棉粕源发酵饲料。结果表明:试验第Ⅱ、Ⅲ、Ⅳ组与第Ⅰ组相比产蛋率均有所提高,其中第Ⅲ组产蛋率最高;平均蛋重、产蛋量、料蛋比均高于对照组但均未达到差异显著水平(P0.05);采食量试验组分别比对照组提高了1.77%(P0.01)、8.83%(P0.01)、8.80%(P0.01);腹泻率、死淘率试验组与对照组差异不显著(P0.05)。由此可见,在蛋鸡日粮中用发酵棉粕代替豆粕,可提高饲料利用率及经济效益,以添加10%的效果最佳。     

牛磺酸对产蛋后期母鸡生产性能的影响

试验采用 14 4只 5 6周龄海兰褐蛋鸡 ,研究添加不同水平的牛磺酸对产蛋后期母鸡生产性能和蛋壳品质的影响。试验结果表明 :添加 0 .0 5 %的牛磺酸能够提高蛋鸡的产蛋率、平均蛋重 ,并且可以降低蛋鸡的日采食量和料蛋比 ,对蛋壳品质也有一定的影响。     

以可消化氨基酸为基础配制日粮对蛋用种母鸡繁殖性能和蛋白质代谢的影响

试验选用480只42周龄海兰父母代蛋种鸡,随机分为5组,每组3个重复,每个重复32只鸡。试验以可消化氨基酸为基础,用杂粕代替部分大豆粕配制日粮,研究了不同日粮对蛋用种母鸡繁殖性能和蛋白质代谢的影响。结果表明:氨基酸平衡的杂粕日粮以及氨基酸平衡的低蛋白质日粮对蛋用种母鸡的日产蛋率、料蛋比、种蛋合格率、受精率和孵化率等繁殖性能指标无显著影响(P>0.05),棉籽粕、菜籽粕、棉菜粕可分别代替5%、5.5%、10%的大豆粕;低蛋白质的氨基酸平衡日粮降低了日产蛋重(P<0.05);血浆尿素N含量以高杂粕日粮组最高,但各组差异不显著(P>0.05);血浆总蛋白含量,高杂粕日粮组比对照组高出78.74%(P<0.05)。     

采用旋刀破碎机加工蛋鸡饲料用破碎玉米的粒度研究

文章就旋刀破碎机加工的蛋鸡用玉米破碎品粒度进行了研究和评定,检测了不同的刀片末端速度及不同筛片孔径下玉米破碎品的粉碎粒度和含粉率(20目筛下物),得出了以下结论:将旋刀破碎机的刀片末端速度从30 m/s降低至20 m/s,可以显著降低玉米破碎物中的含粉率;旋刀破碎机配备φ8 mm筛片,刀片末端速度30 m/s时的D_(gw)为1763μm,S_(gw)为1.08,玉米粉碎粒度十分均匀,比较适合蛋鸡的需求。     

Establishing an essential amino acid profile for maintenance in poultry using deletion method

This study aimed to estimate the essential amino acid profile and the ideal ratio for the maintenance of poultry by deletion method. A nitrogen balance (NB) trial was conducted using 198 adult roosters, housed individually in metabolic cages. The treatments were 33 purified diets being 11 diets with an amino acid mixture providing high protein intake of 500 mg N/BW_kg^0.75 per day, 11 diets providing medium protein intake of 250 mg N/BW_kg^0.75 per day (in each diet, one amino acid tested was diluted 50%) and 11 diets providing low protein intake of 125 mg N/BW_kg^0.75 per day (made by omitting the amino acid tested). Each treatment had six replicates. After 48 h of fasting receiving water plus sucrose, the roosters were fed 40 g of the diets by tube once a day for 3 days. The excreta were collected within 72 h after the first feeding. The diets and excreta were analysed for nitrogen content. For each amino acid studied, a linear regression was fitted by NB and amino acid intake (AAI). The maintenance requirements were estimated as the AAI to maintain the NB equal to zero. The daily amino acid requirements for maintenance were estimated to be Lys 11, Met 29, Thr 23, Trp 5, Arg 50, Val 29, His 6, Gly 54, Phe 49, Leu 78 and Ile 21 mg/BW_kg^0.75 per day. Therefore, the amino acid ratio for maintenance was concluded to be Lys 100, Met 276, Thr 220, Trp 48, Arg 467, Val 275, His 60, Gly 511, Phe 467, Leu 735 and Ile 198% independent of the scale. The essential amino acid profile and the ideal ratio for the maintenance of poultry estimated in this study contributed to improve the factorial model for estimating essential amino acid requirements for poultry.     

Effect of dietary energy concentration on the response of laying hens to amino acids

1. A hypothesis, that the optimum amino acid concentration in the diet is not directly proportional to the dietary energy concentration, but changes in inverse proportion to the change in food intake resulting from a change in energy concentration, was tested in three experiments.

2. Response experiments involving the amino acids methionine, lysine and isoleucine were conducted, in each case at three dietary energy concentrations, using a diet dilution and blending technique, thereby ensuring a constant ratio between background amino acids and the first‐limiting amino acid in all diets, and also keeping the ratio of amino acids to energy constant as energy varied.

3. A common response curve relating egg output (g/bird d) to amino acid intake (mg/bird d) for each amino acid, fitted by means of the Reading Model, adequately described the response at each of the dietary energy contents. This implies that energy does not influence egg output directly, but only indirectly through its effect on food intake and hence on amino acid intake.

4. Both amino acid and energy concentration significantly influenced food intake. Energy intake was not constant over all dietary energy concentrations, being lower at low energy levels and higher at high energy concentrations.

5. It is concluded that amino acid requirements should not be stated either as percentages or as ratios with energy. Optimum amino acid intakes and energy concentrations should be calculated; the expected food intake should then be predicted, after which the appropriate concentration of nutrients in the diet can be determined.