共查询到20条相似文献，搜索用时 15 毫秒
1.
Optimum threonine requirement of laying hens 总被引：1，自引：0，他引：1
1. One experiment was conducted with medium weight laying hens to determine their threonine requirement between 28-38 weeks. 2. Two threonine-limiting diets of identical protein quality (summit-dilution) were used and, by dilution, ten protein contents were produced supplying 2.7 to 5.4 g total threonine/kg diet. The diet with the lowest protein was also supplemented with synthetic L-threonine. Each diet was fed to 5 groups of 24 laying hens. 3. The daily threonine requirement of the individual laying hens was estimated by direct methods to be 8.7 mg/g egg output plus 43.49 mg/kg body weight for this experiment. Calculated optimum intakes of threonine for various ratios of costs of input to value of output are tabulated. For example, for a flock of medium weight laying hens producing an average of 50 g daily egg mass, the optimum threonine intake (mg/hen d) varied between 700 and 710 for cost ratios (k-values) varying between 0.002 and 0.001. 相似文献
2.
A 24-week performance trial was conducted to evaluate the efficacy of an experimental phytase on performance, egg quality, tibia ash content and phosphorus excretion in laying hens fed on either a maize- or a barley-based diet. At the end of the trial, an ileal absorption assay was conducted in order to determine the influence of phytase supplementation on the apparent absorption of calcium and total phosphorus (P). Each experimental diet was formulated either as a positive control containing 3.2 g/kg non-phytate phosphorus (NPP), with the addition of dicalcium phosphate (DCP), or as a low P one, without DCP addition. Both low P diets (containing 1.3 or 1.1 g/kg NPP) were supplemented with microbial phytase at 0, 150, 300 and 450 U/kg. The birds were housed in cages, allocating two hens per cage as the experimental unit. Each of 10 dietary treatments was assigned to 16 replicates. Low dietary NPP (below 1.3 g/kg) was not able to support optimum performance of hens during the laying cycle (from 22 to 46 weeks of age), either in maize or barley diets. Rate of lay, daily egg mass output, feed consumption, tibia ash percentage and weight gain were reduced in hens fed low NPP diets. The adverse effects of a low P diet were more severe in hens on a maize diet than in those on a barley diet. Low dietary NPP reduced egg production, weight gain, feed consumption and tibia ash content and microbial phytase supplementation improved these parameters. Hens given low NPP diets supplemented with phytase performed as well as the hens on positive control diets containing 3.2 g/kg of NPP. A 49% reduction of excreta P content was achieved by feeding hens on low NPP diets supplemented with phytase, without compromising performance. Phytase addition to low NPP diets increased total phosphorus absorption at the ileal level, from 0.25 to 0.51 in the maize diet and from 0.34 to 0.58 in the barley diet. Phosphorus absorption increased linearly with increasing levels of dietary phytase. Mean phosphorus absorption was higher in barley diets than in maize diets (0.49 vs 0.39). 相似文献
3.
1. Broiler breeder hens were used in an experiment lasting 10 weeks (29 to 38 weeks of age) to measure the responses to dietary lysine and methionine, the main objective being to determine whether the coefficients of response to these amino acids were the same for broiler breeders and for laying pullets. 2. The hens were offered 150 g/d of one of 20 dietary treatments, 10 being lysine-limiting and 10 being methionine-limiting. The diets were mixed by diluting one of two concentrate (summit) mixes with a protein-free dilution mixture. The lysine-limiting summit diet was designed to supply approximately 1300 mg lysine/bird d, while the other supplied 520 mg methionine/bird d, when fed at 150 g/bird d. 3. Birds on the 5 lowest concentrations of both lysine and methionine did not consume the allotted amount of food, the amount decreasing, in a curvilinear fashion, to approximately 105 g/bird d. 4. The minimum egg weight recorded was 0.8 of the maximum, whereas the rate of lay of birds fed on the diets with the lowest amino acid concentrations was 0.2 of the maximum. 5. Using the Reading Model, the coefficients of response were calculated to be (for lysine) 16.88 E and 11.2 W, and for methionine, 7.03 E and 1.52 W, where E = egg output, g/bird d, and W = body mass, kg/bird. An average, individual, broiler breeder of 3 kg, producing 45 g of egg output per day, would need 793 mg of lysine and 321 mg of methionine daily. This intake of methionine is similar to that estimated by means of coefficients used for laying pullets, but the lysine requirement would be underestimated by 0.18 if the coefficients for laying pullets were used. 6. The coefficients for maintenance for both lysine and methionine, determined in this experiment, are considerably lower than values published previously, whilst the coefficients for egg output are, in both cases, higher. The resultant flock response curves therefore differed significantly from those in which the coefficients of response for for laying pullets were used.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
4.
本试验旨在研究日粮中添加辣诺素（辣木和诺丽果的提取物）对蛋鸡生产性能及蛋品质的影响。将产蛋高峰期（22周龄）的海兰褐商品蛋鸡540只随机分为6个处理,每个处理6个重复,每个重复15只鸡。负对照组（NC）饲喂基础日粮,正对照组（PC）饲喂添加50 mg/kg杆菌肽锌的基础日粮,4个试验组分别饲喂添加0.25、0.50、0.75和1.00 g/kg辣诺素（LNS）的基础日粮。试验期24周。结果显示：①日粮处理对蛋鸡试验前期和后期生产性能均无显著影响（P>0.05）,试验后期添加0.50和0.75 g/kg辣诺素有改善料蛋比的趋势（P=0.087）;日粮处理对试验前期和后期鸡蛋蛋形指数、蛋壳强度、蛋壳厚度、蛋黄重和哈氏单位均无显著影响（P>0.05）,但日粮中添加杆菌肽锌和辣诺素有提高蛋壳强度的趋势（P=0.062）,其中以添加0.75g/kg辣诺素组鸡蛋强度最高。②与正、负对照组相比,添加辣诺素显著增加了生蛋黄和熟蛋黄的罗氏蛋黄色比率（P<0.05）,显著降低了蛋黄胆固醇的含量（0.25 LNS组除外）（P<0.05）。③与负对照组相比,添加0.50 g/kg辣诺素显著提高了鸡蛋总黄酮、二十二碳六烯酸（DHA）、卵磷脂、亚麻酸和亚油酸含量（P<0.05）。综合以上试验结果,辣诺素作为饲料添加剂具有提高鸡蛋营养品质的功能,考虑到添加成本,产蛋鸡日粮中添加0.25~0.50 g/kg为宜。 相似文献
5.
《The Journal of Applied Poultry Research》2014,23(4):683-690
Considering that Val may potentially be a limiting amino acid for laying hens, an experiment was carried out to determine the ideal digestible Val-to-Lys ratio in the diets of 42- to 54-wk-old brown layers. Literature reports are divergent, with ratios varying between 86 and 102%, which suggests that further research is needed. Five different digestible Val-to-Lys ratios were evaluated: 84 (0.555% digestible Val), 88, 92, 96, and 100%. Feed intake (g/hen per day), egg production (%), egg weight (g), egg mass (g), FCR (kg/dozen and g/g), egg quality (yolk, eggshell, and albumen %), and egg weight (g) were evaluated. Egg weight, egg internal quality, and weight gain were not influenced by the different dietary digestible Val-to-Lys ratios. The evaluated ratios linearly affected feed intake and had a quadratic effect on egg production, egg mass, and FCR (kg/dozen and g/g). Based on the evaluated parameters, the ideal digestible Val-to-Lys ratio is 92%, corresponding to 0.607% digestible Val or 567 mg/hen per day of digestible Val. 相似文献
6.
1. Two experiments were conducted with laying pullets between 32 and 47 weeks of age. In each trial 1 728 White Leghorn and 1 728 crossbred pullets were used.
2. A series of diets of increasing protein content was offered. Protein quality was identical in all diets and tryptophan was demonstrated to be the most limiting amino acid in the protein mixture used.
3. The daily tryptophan requirement of the individual pullet was estimated, by indirect methods, to be 2.25 mg/g egg output plus 10.25 mg/kg body weight. Response curves for flocks of pullets are illustrated. Calculated optimum intakes of tryptophan for various ratios of costs of input to value of output are tabulated.
4. It is estimated that for a flock of mean body weight 1.5 kg, producing 55 g egg mass/hen d and consuming 110 g food/hen d, the optimum dietary tryptophan concentration is 1.7 g/kg when the marginal cost of supplying 1 kg tryptophan is 20 times the marginal value of 1 kg egg output. 相似文献
7.
1. The performance of White Leghorn laying hens on diets providing pearl millet (Pennisetum typhoides) at 300 and 600 g/kg to replace maize, part per part, or "maize mix" isoenergetically and isonitrogenously in the first experiment and at 600 g/kg diet to replace maize in toto, part per part, in the second experiment were examined. In the first experiment, 3 groups of 12 laying hens were placed on each of the 5 dietary treatments for 3 x 28 d, whereas in the second experiment, each of the two diets was offered to 10 groups of 15 laying hens for 6 x 28 d. 2. Inclusion of pearl millet in the diet at the expense of maize, part per part, did not significantly influence hen-day egg production, feed intake, feed efficiency and body weight in either experiment. Incorporation of pearl millet isoenergetically at the expense of "maize mix" at any level, i.e. 300 g or 600 g/kg (Experiment 1), also did not influence hen-day egg production but at the end of periods 2 and 3 did result in decreased feed intakes with consequent improvements in feed efficiency. 3. Egg weight in general showed a tendency to improve with diets providing pearl millet at 600 g/kg. 4. Profits from egg sales over feed cost were directly proportional to the inclusion of pearl millet in the diet either at the expense of maize, part per part, or "maize mix" isoenergetically. 相似文献
8.
本研究旨在评估夏季高温时日粮添加甜菜碱对蛋鸡生产性能、蛋品质及骨骼和血液理化特性的影响.试验将480只产蛋性能一致的罗曼粉壳蛋鸡随机分为2组,每组240只,每组10个重复(24只/重复).对照组饲喂基础试验日粮,处理组蛋鸡饲喂基础试验日粮+150?mg/kg甜菜碱,试验为期8周.结果:日粮添加150?mg/kg甜菜碱对... 相似文献
9.
试验旨在研究添加不同剂量的粪肠球菌对产蛋后期蛋鸡生产性能、蛋品质及肠道形态结构的影响。选取70周龄产蛋率相近的海兰褐蛋鸡270只,随机分为3个处理,每个处理6个重复,每个重复15只鸡。试验设对照组（饲喂基础日粮）、试验Ⅰ组（基础日粮+3.75 mg/kg粪肠球菌）和试验Ⅱ组（基础日粮+7.5 mg/kg粪肠球菌）,预试期7 d,正试期50 d。结果表明,与对照组相比,试验Ⅰ、Ⅱ组产蛋后期蛋鸡产蛋率、产蛋量极显著提高（P<0.01）,料蛋比极显著降低（P<0.01）;与对照组相比,试验Ⅰ、Ⅱ组蛋鸡的蛋壳厚度、蛋壳强度、蛋形指数、蛋白高度、哈夫单位、蛋黄相对重、蛋壳相对重均无显著变化（P>0.05）;与对照组相比,试验Ⅰ、Ⅱ组产蛋后期蛋鸡十二指肠、回肠的黏膜厚度极显著增加（P<0.01）,回肠绒毛高度显著提高（P<0.05）。综上所述,在产蛋后期蛋鸡日粮中添加适宜剂量的粪肠球菌可提高蛋鸡生产性能,改善肠道形态结构。 相似文献
10.
试验采用氮平衡试验研究产蛋高峰期罗曼公、母鸡的氮维持需要量(Nm),并分析公、母鸡氮代谢的变化规律。试验选取27周龄健康的公、母鸡各30只,分别分为5个处理,每处理6个重复,每个重复1只试鸡,对公、母鸡分别饲喂5个不同粗蛋白质水平的试验日粮。结果表明:相同蛋白水平处理组的公鸡氮食入量和氮沉积率均高于母鸡的结果。母鸡和公鸡的氮食入量(NI)与氮沉积量(NB)间的回归方程分别为NB=0.3743NI-0.1589(R2=0.79)和NB=0.6228NI-0.3151(R2=0.85)。母鸡和公鸡的氮维持需要量分别为每天0.4245g和0.5059g;每千克体重0.2364g和0.2754g;每千克代谢体重0.2739g和0.3208g。 相似文献
11.
本试验旨在研究日粮不同水平抗菌肽粗提物对蛋鸡产蛋性能、蛋品质、血清生化指标和肠道菌群的影响。将480只210日龄海赛克斯褐壳蛋鸡,随机分成4组,每组4个重复,对照组饲喂基础日粮,试验组分别饲喂在基础日粮中添加200、400、600 mg/kg抗菌肽粗提物的试验日粮。结果表明:与对照组相比,日粮添加200 mg/kg抗菌肽粗提物能显著提高蛋鸡的蛋黄相对重(P<0.05),对回肠内大肠杆菌有显著抑制作用(P<0.05),而对其他指标并无显著性影响(P>0.05);日粮添加400 mg/kg抗菌肽粗提物能显著提高蛋鸡的产蛋率和蛋黄相对重(P<0.05),降低白蛋白和血糖含量(P<0.05),显著降低回肠大肠杆菌的数量(P<0.05);日粮添加600 mg/kg抗菌肽粗提物能够显著提高血清SOD活性(P<0.05),而对其他指标无显著性影响(P>0.05)。综上所述,蛋鸡日粮中添加400 mg/kg抗菌肽粗提物效果最佳。 相似文献
12.
Data relating egg output to daily intakes of lysine, methionine, tryptophan, isoleucine and valine have been analysed using both published and unpublished sources. Amino acid requirements in mg/d for individual pullets were estimated by the following equations: (Table: see text) where E = egg output in g/d and W = body weight in kg. Response curves for flocks of pullets were calculated using the Reading model and optimum intakes were derived for various body weights, egg outputs and ratios of input costs to output values. Estimates of amino acid maintenance requirements were related to reported values for the adult cockerel and the amino acid requirement for egg output was related to the digestibility of amino acids and the composition of egg protein. Procedures are suggested for deriving response coefficients for other essential amino acids. 相似文献
13.
Four experiments with 270, 44, 432 and 66800 Leghorn hens were carried out to investigate the influence of various Mn additions to diets differed in mineral or Ca contents on egg shell quality. The addition of 300 mg Mn/kg diet improved significantly egg shell breaking strength by 4 N over one year. The supply of 50-500 mg Mn/kg diet for 10-24 weeks of the second half of laying year did not influence the egg shell quality. Addition of mineral mixture or Ca grit to layer rations with adequate or higher Mn levels did not influence egg shell strength. High mineral content in a low manganese diet increased number of cracks by 3%. Strength, weight and ash content of tibia were significantly reduced by feeding a low mineral level. Addition of 50-150 mg Mn per kg low mineral diet normalized partially tibia stability in young hens. It was concluded that supplied dietary Manganese influences calcification positively only in young hens. High levels of Ca did not influence the effects of Mn. 50 mg Mn per kg layers mixture have been considered as an essential supply. 相似文献
14.
This experiment was conducted to evaluate the effects of chromium (chromium picolinate, Cr Pic) and vitamin C (L-ascorbic acid) supplementation on egg production and egg quality in laying hens (Hy-Line) kept at 18 degrees C (at thermo-neutral zone) or 6 degrees C (cold stress) in temperature-controlled rooms. One hundred and fifty laying hens (32 week-old) were divided into 5 groups, 30 hens per group. The laying hens kept at 6 degrees C temperature were fed either a basal diet (low temperature-basal diet, LTB group) or the basal diet supplemented with either 400 micrograms of Cr per kg diet (Cr group), 250 mg of L-ascorbic acid per kg diet (Vit C group) or 400 micrograms of Cr plus 250 mg of L-ascorbic acid per kg diet (Vit C + Cr group) while hens kept at 18 degrees C fed a basal diet (thermo-neutral-basal diet, TNB group). Performance and egg quality were significantly reduced in LTB group compared with TNB group. Supplemental chromium and vitamin C significantly increased live weight change, egg production, and improved feed efficiency in cold-stressed hens compared with group fed the basal diet at 6 degrees C brought up to the values of the group reared under thermoneutral conditions (18 degrees C). Egg production and egg weight were also greater in each supplemental group compared with the LTB group. Separately or as a combination, supplemental chromium and vitamin C increased serum insulin but decreased corticosterone, glucose and cholesterol concentrations. Results of the present study show that supplementing vitamin C and chromium, particularly as a combination, improved the performance of cold-stressed hens. Such a combination of supplement can offer a potential protective management practice in preventing cold stress-related losses in performance of laying hens. 相似文献
15.
1. This experiment was carried out to determine the effects of dietary iodine supplementation on the performance and egg traits of laying hens. A total of 600 SHSY type brown layers aged 21 weeks of age were chosen at random from a large flock. They were randomly distributed into 30 pens at 20 hens per pen. Each treatment comprised 6 replicates of 20 layers in groups of 5 birds. The diets were supplemented with 0, 3, 6, 12 and 24 mg/kg iodine as calcium iodate. The experimental period lasted 30 weeks. 2. There were no significant differences among the groups in body weight, food consumption, egg production, food consumption per kg eggs, eggshell index, eggshell breaking strength, shell thickness or egg yolk index. 3. Supplementation of the diet with 12 mg/kg iodine increased food consumption per dozen eggs compared to the groups fed on diets supplemented with 0 and 6 mg/kg iodine. 4. Egg weight was less in groups fed on diets supplemented with 12 and 24 mg/kg iodine than in the group receiving no iodine supplementation. 5. Iodine supplementation to provide 12 and 24 mg/kg reduced egg albumen index and egg Haugh units. 6. There were no significant differences among the groups in egg cholesterol and egg yolk cholesterol contents. 7. The iodine concentrations in egg yolk, egg albumen and whole egg increased with increased iodine supplementation. 8. As a result, the 3 and 6 mg/kg iodine supplementation of diet could be used to enrich the eggs with iodine without any adverse effect on performance and egg traits. 相似文献
16.
M D Olver 《British poultry science》1989,30(1):115-121
1. One hundred and twenty 16-week-old, single combed pullets of three strains were fed on a diet containing 160 g protein/kg with or without 50 g clinoptilolite/kg in a trial with 20 hens per treatment. Sterile river sand replaced clinoptilolite in the control diet in order to keep the diets isonergetic. 2. The hens were individually caged in a naturally-ventilated laying house and fed on one of the two diets for ten 28-d periods. 3. No significant dietary effects between treatments were observed with respect to body weight, age at first egg, egg weight, Haugh scores or food intake/hen. 4. Significant dietary effects in favour of clinoptilolite feeding were noticed with the number of eggs laid per hen, shell thickness, efficiency of food utilisation, droppings moisture content and mortality. 5. Significant differences between strains were observed with respect to all measurements taken except food intake/hen d. 相似文献
17.
文章旨在研究日粮中不同梯度维生素E添加水平对蛋鸡产蛋后期产蛋性能和蛋品质的影响。试验选择60周龄罗曼白壳商品蛋鸡300羽,试验随机分为5组,添加水平分别为0(对照组),30、60、120、240 mg/kg,每组6个重复,每个重复10羽鸡,预试期1周,正试期8周。结果表明:与对照组相比,蛋鸡产蛋后期日粮中添加120 mg/kg的维生素E可显著提高蛋鸡产蛋后期产蛋性能(P<0.05);与对照组相比,蛋鸡产蛋后期日粮中添加120 mg/kg的维生素E可显著提高蛋壳硬度、蛋壳相对重、蛋黄相对重以及蛋黄颜色(P<0.05),蛋黄总胆固醇含量极显著降低(P<0.01)。综上所述,在蛋鸡产蛋后期日粮中添加120 mg/kg的维生素E可显著改善其产蛋性能和蛋品质。 相似文献
18.
试验探讨维生素E对免疫抑制蛋鸡生产性能和蛋品质的调控效应,选取健康的尼克褐产蛋鸡270只,随机等分为5组,每组3个重复,每重复18只。第Ⅰ组为对照组,第Ⅱ~Ⅴ组为免疫抑制组,对第Ⅱ~Ⅴ组鸡在试验第5、6、7 d进行腿部肌肉注射80 mg/kgBW环磷酰胺(CTX),第Ⅰ组注射等量生理盐水。Ⅰ、Ⅱ组饲喂基础日粮(维生素E含量44.59 mg/kg),Ⅲ、Ⅳ、Ⅴ组在基础日粮中分别添加50、100、200 mg/kg维生素E。结果显示:①免疫抑制产蛋鸡的产蛋率、平均蛋重和平均日采食量显著降低(P<0.05),破蛋率显著升高(P<0.05)。基础日粮中添加50 mg/kg维生素E显著提高免疫抑制产蛋鸡的产蛋率、平均蛋重和平均日采食量(P<0.05),但仍低于对照组Ⅰ(P<0.05);显著降低料蛋比和破蛋率(P<0.05)。②免疫抑制产蛋鸡的蛋壳厚度、蛋壳强度和哈氏单位显著降低(P<0.05),蛋形指数和蛋黄颜色无显著改变(P>0.05);50 mg/kg维生素E添加量显著提高免疫抑制产蛋鸡的蛋壳厚度、蛋壳强度和哈氏单位(P<0.05),与对照组Ⅰ无显著差异(P>0.05)。因此,免疫抑制显著降低产蛋鸡的生产性能和蛋品质;基础日粮中添加维生素E对免疫抑制蛋鸡的生产性能和蛋品质具有明显的调控效应,且以50 mg/kg添加量效果较好。 相似文献
19.
After N-balance experiments with broiler hens in the top laying period and the feeding of soybean coarse meal/fish meal protein the protein utilisation values were calculated. The PNu curve and the PEW curve could be described as utilisation values from the N-retention curve (e-function). At an intake of N at which the hen neither decomposed nor retained protein, the utilisation (PNu) for maintenance and egg production was 55.3% and the utilisation of feed protein for egg production 49.4%. Maximum PEW 34.3% could only be ascertained at an N-intake/LW0.67kg of 1500 mg. The corresponding crude protein quota of 18.7 g recommended as crude protein requirement is calculated from this N-quota (xm) and a live weight of the broiler hen of 2804 g. For the same N-quota (xm) and the same live weight of the hens this results in a necessary quota of S-AA of 694 mg per hen and day. Provided the daily feed intake is 145 g and thus the intake of crude protein 18.7 g and that of S-AA 694 mg per hen, the necessary crude protein content of the feed is 130 g per kg original substance and an S-AA concentration which is equivalent to 3.7% of the crude protein (in g/16 g N). 相似文献
20.
1. A commercial enzyme preparation (Quatrazyme HP) containing xylanase and beta-glucanase was examined in two laying hen experiments with wheat/barley- or maize-based diets. The activities of other enzymes were measured also. Starch, cell wall contents and effects of Quatrazyme HP on in vitro viscosity of wheat, barley, maize and soybean meal were determined. 2. In the first experiment, 90 ISA Brown laying hens at 28 weeks of age were given a wheat/barley basal diet with or without 20mg of Quatrazyme HP, which provided 560 and 2,800 IU of xylanase and beta-glucanase/kg diet. In the second experiment, 66 ISA Brown laying hens at 45 weeks of age were given a maize/soybean meal basal diet with or without 20 mg of Quatrazyme HP/kg diet for 9 weeks. Egg production, egg weight, egg mass, feed conversion ratio and change in body weight were recorded as response criteria. 3. There was a significant improvement in feed conversion ratio with enzyme supplementation. Birds given an enzyme-supplemented diet gained 86 g while those fed on the unsupplemented diet lost 103 g of their body weight by the end of the experiment. 4. The enzyme preparation did not affect either egg production, egg weight or egg mass of birds fed on the maize/soybean meal diet. However, a significant improvement in feed conversion ratio was detected. Birds on either the supplemented or unsupplemented diet exhibited an increase in their body weight at the end of the experiment. 5. Addition of xylanase and beta-glucanase decreased in vitro viscosity of wheat, barley, maize and soybean meal. This effect was greater for wheat and barley than for maize and soybean meal. 6. It was concluded that the beneficial effect of using an enzyme preparation containing xylanase and beta-glucanase is not limited to wheat/barley-based diets but also occurs with maize/soybean meal-based diets. 相似文献