Effects of dietary conjugated linoleic acid and fish oil supplementation on performance and egg quality in laying hens

1. Laying hen performance, yolk fat fatty acid concentrations and firmness of eggs were evaluated with respect to the inclusion in the diet of conjugated linoleic acid (CLA) and fish oil. 2. Nine diets were arranged factorially, with three levels of supplementation of CLA (1, 3 and 5 g/kg) and fish oil (0, 14 and 20 g/kg). 3. Type of diet did not affect egg production traits. 4. CLA addition increased yolk weight and yolk fat concentrations of CLA, saturated and total long-chain n-3 fatty acids, but decreased those of monounsaturated and total long-chain n-6 fatty acids. 5. Fish oil addition increased long-chain n-3 fatty acids yolk fat concentrations but decreased those of CLA, saturated and long-chain n-6 fatty acids. 6. Effects of CLA addition on yolk fat concentrations of C22:4 n-6 and C20:5 n-3 were greater when no fish oil was added to the diet. 7. CLA supplementation increased linearly yolk moisture and firmness and altered albumen and yolk pH.     

Effects of dietary conjugated linoleic acid and high-oleic sunflower oil on performance and egg quality in laying hens

(1) Laying hen performance, yolk fatty acid (FA) concentrations, sensory quality and firmness of eggs were evaluated with respect to the inclusion in the diet of conjugated linoleic acid (CLA) and high-oleic acid sunflower oil (HOSO). (2) Nine diets were arranged factorially, with three concentrations of CIA (0, 1 and 2 g/kg) and HOSO (10, 20 and 30 g/kg). (3) Type of diet did not affect egg production traits. (4) Dietary addition of CLA decreased yolk lipid content and yolk lipid concentrations of monounsaturated FA, C(20:4 n-6) and C(22:6 n-3), but increased those of CLA and saturated FA. (5) Dietary addition of HOSO increased monounsaturated FA concentrations in the yolk lipid but decreased those of CLA and saturated FA. (6) CLA supplementation increased yolk moisture and firmness and impaired the sensory quality of eggs. (7) An interaction between CLA and HOSO addition was found as effects of CLA addition on yolk lipid CLA concentrations and egg quality traits were smaller when the amount of HOSO in the diet increased. (8) Regression equations have been calculated in order to predict yolk CLA and C(18:1), concentration from dietary composition, and yolk firmness from yolk FA composition.     

共轭亚油酸对蛋鸡生产性能及蛋黄腊肪酸含量的影响

本文旨在研究不同共轭亚油酸(CLA)添加水平对蛋鸡生产性能及蛋黄脂肪酸含量的影响.选用30周龄罗曼商品蛋鸡96只,随机分成4个处理组,每个处理组6个重复,每个重复4只鸡,分别饲喂添加0%、0.5%、1%和2%共轭亚油酸的基础日粮,试验期为印d.结果表明,添加共轭亚油酸对蛋鸡生产性能、蛋黄重量和蛋黄脂肪含量的影响不显著,但添加1.0%和2.0%共轭亚油酸,鸡的采食量和蛋清重显著降低(P<0.05);随着日粮共轭亚油酸添加水平的提高,蛋黄中胆固醇和单不饱和脂肪酸含量降低(P<0.05),蛋黄中饱和脂肪酸、多不饱和脂肪酸和共轭亚油酸含量显著提高(P<0.05).本试验条件下,2%共轭亚油酸添加组对于提高蛋黄的共轭亚油酸含量,降低蛋黄的胆固醇含量效果最佳.     

Exogenous enzyme complexes and linoleic acid to laying hens

The aim of this research was to evaluate how the decrease of fat inclusion (and therefore compounds essential for animal development, such as linoleic acid) and the use of exogenous enzyme complexes can affect the performance of layers. Treatments consisted of diets with different levels of linoleic acid, the negative control (NC) with 2.41 g/100g and positive control (PC) with 3.75g/100g. Treatment 3 (RLLA) was reformulated using enzymes and low levels of linoleic acid equal to the NC, treatment 4 (RILA) and treatment 5 (RHLA) were reformulated using enzymes, but with linoleic acid at moderate (3.08 g/100g) and high levels (3.75 g/100g), respectively. The formulation of treatments 3, 4, and 5 used enzymes reformulated using an enzyme nutritional matrix. The variables analyzed in each period were the feed intake (g/bird/day); egg production (%); egg weight (g); egg mass (g); feed conversion per egg mass (kg/kg) and per dozen eggs (kg/dozen); weight (g) of yolk, albumen, and shell; specific gravity (g/cm³); Haugh unit; and shell thickness (mm). The commercial enzyme supplementation was effective in supporting the productive performance of the laying hens. Nutritional reduction in diets reformulated with supplementation of the commercial enzymes can be an alternative to reduce production costs without compromising the productive performance of hens.     

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.     

能量水平对粉壳蛋鸡生产性能及蛋品质量的影响

为研究不同能量水平对产蛋性能和蛋品质量的影响,试验选用504只194日龄罗曼粉蛋鸡,试验共设3个处理,每个处理5个重复,每个重复33～35只,分别饲喂三个能量水平(10.88、11.09、11.30 MJ/kg)的日粮。试验共进行30 d。试验结果表明,各处理组在采食量、产蛋率、平均蛋重、料蛋比、蛋壳强度和哈夫单位等方面差异不显著;表明能量水平在50～100 kcal/kg范围内波动,对蛋鸡生产性能和蛋品质量未产生显著影响。     

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.     

Energy content of select dietary supplemental lipids for broilers,turkeys, and laying hens

Energy is an expensive component of poultry diets with lipids providing a concentrated energy source to meet these needs. Three separate experiments with broilers (15 d of age), turkeys (15 d of age) and laying hens (60 wk of age) were conducted to determine the AME_n content of 10 lipids with varying fatty acid and free fatty acid concentrations and to compare these values to predicted values based on previously published equations. A corn-soybean meal (broilers and turkeys) or corn-soybean meal-distillers dried grains with solubles (layers) control diet was formulated with test diets created by mixing the control diet with 0, 3, 6, or 9% (broilers and turkeys) or 0, 2, 4, and 6% (laying hens) lipid. Experimental diets were fed over a 5-d acclimation period followed by a 48 h total excretion collection period with AME_n of the diets calculated based upon the GE, nitrogen, and titanium dioxide in the feed and excreta samples. The pen-mean AME_n of each diet was regressed on percentage lipid inclusion level using linear regression with the slope of the line representing the AME_n of each lipid source. As expected, the AME_n values varied widely among lipid sources and species, with broilers having a greater AME compared to turkeys and layers. In general, saturated fatty acids (C14:0, C16:0, and C18:0) were negatively correlated to AME_n while unsaturated fatty acids (namely C18:2) were positively correlated to AME_n. Consequently, the unsaturated: saturated ratio, the polyunsaturated fatty acids: saturated and monounsaturated fatty acids ratio, and iodine value tended to be positively related to AME_n. Compared to broilers and turkeys that were able to efficiently utilize energy from corn oil (purified and crude DDGS corn oil) relative to soybean oil, laying hen AME_n values for corn oils were reduced in comparison to soybean oil. These data indicate that energy values of lipid differ widely due to source and appear to differ relative to a particular species.     

Effect of dietary digestible lysine concentration on performance,egg quality,and blood metabolites in laying hens

An experiment was conducted to evaluate the effect of dietary digestible lysine concentration on productive performance, egg quality, and blood metabolites in laying hens. A completely randomized block design was performed with 5 treatments and 6 replicates of 8 Hy-line W-36 hens each, from 32 to 44 wk of age. The treatments were 5 digestible lysine concentrations (0.657, 0.707, 0.757, 0.807, and 0.857% of diet). Feed intake was significantly increased with each increment in dietary digestible lysine concentration. Significant improvement in egg production, egg weight, egg mass, Haugh unit, and FCR were observed by an increase in lysine intake. Dietary lysine concentration did not have a significant impact on percentage of egg components, specific gravity, eggshell thickness, DM, and protein constituents of eggs. Dietary digestible lysine concentration did not have a significant effect on triglyceride, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), uric acid, and total protein in plasma. The digestible lysine requirements for optimal egg production, egg mass, and egg weight (32 to 44 wk of age), based on the linear broken-line regression analysis, were 814, 810 and 778 (mg/b/d), respectively. Whereas, these values were 4, 3.9, and 6 percent less than those estimated by the quadratic broken-line model, respectively.     

Bone structure and strength at different ages in laying hens and effects of dietary particulate limestone,vitamin K and ascorbic acid

1. A range of bone structural and strength characteristics was determined in laying hens at 15, 25, 50 and 70 weeks of age. The birds were fed up to 25 weeks on diets supplemented with additional vitamin K (10 mg menadione/kg) or ascorbic acid (250 mg/kg) or up to 70 weeks on diets containing limestone in powder or particulate form. 2. There were important effects of age on all bone characteristics. Between 15 and 25 weeks there was a rapid loss of cancellous bone and a rapid accumulation of medullary bone in the proximal tarsometatarsus (PTM). These changes continued at a slower rate up to 70 weeks. Cancellous bone content of the free thoracic vertebra (FTV) also declined after 15 weeks. 3. Breaking strengths of tibia and humerus did not change between 15 and 25 weeks but decreased later in lay. 4. None of the nutritional treatments affected bone characteristics at 15 weeks of age. 5. Increasing the dietary vitamin K supplement from 2 to 12 mg menadione/kg increased cancellous bone volume in the PTM at 25 weeks. 6. Dietary ascorbic acid did not affect any of the bone characteristics measured up to 25 weeks. 7. Particulate limestone resulted in a smaller loss of cancellous bone between 15 and 25 weeks and increased accumulation of medullary bone in the PTM. Breaking strength of the tibia and radiographic densities of tibia and keel were also improved. 8. It is concluded that patterns of bone loss over the lifetime of laying hens vary, depending upon the bone type. Feeding a particulate source of calcium can help to alleviate some of the characteristics of osteoporosis. Supplementation with extra vitamin K may also be beneficial.     

Effects of dietary conjugated linoleic acid isomers on several functional properties of macrophages and heterophils in laying hens

1. Effects of dietary conjugated linoleic acid (CLA) on various functional properties of macrophages and heterophils in the laying hen were determined. 2. Seventy two 28-week-old-ISA brown hens were randomly assigned to one of two experimental groups and were fed diets containing 0 or 1% CLA for a total period of 18 weeks. Blood samples were collected from 6 hens per diet group every 3 weeks and macrophages and heterophils were isolated. The following variables were determined in resting and phorbol myristate acetate-activated (65 microM) macrophages and heterophils: total cell-associated urokinase plasminogen activator (u-PA), membrane-bound u-PA, free u-PA binding sites and superoxide production. 3. There were no significant differences between diet groups throughout the whole experimental period in total cell-associated u-PA, membrane-bound u-PA, free u-PA binding sites and superoxide production by resting macrophages and heterophils. 4. Activated heterophils and macrophages isolated from hens fed the CLA-supplemented diet had higher membrane-bound u-PA activity compared with the corresponding values for activated heterophils and macrophages obtained from hens fed the basal diet. These differences were significant for heterophils during weeks 6, 12, 15 and 18 and for macrophages during weeks 6, 9 and 12 of the experiment. 5. Macrophages and heterophils from hens fed the CLA diet had lower superoxide production compared with the corresponding cells from the control hens on weeks 12, 15 and 18 of the experiment. 6. Dietary CLA modulated certain aspects of the immune system in the laying hen. The increased quantity of u-PA on the membrane of macrophages and heterophils isolated from hens fed the CLA diet may facilitate the ability of these cells to reach the point of a potential inflammation (pro-inflammatory effect). 7. In contrast to the effect on the u-PA system, dietary CLA reduced superoxide production by activated macrophages and heterophils during the second half (last 9 weeks) of the experimental period suggesting that CLA may exert an anti-inflammatory effect in the laying hen.     

Effect of dietary fibre on the performance of laying hens

1. In tests to determine whether gizzard weight could be influenced by dietary fibre concentrations, caged layers were fed on diets containing 15, 30 or 60 g pine shavings/kg diet.

2. As dietary fibre content increased, gizzard weight increased, but there was no effect on body weight, hen‐day production, egg weight, efficiency of food conversion, mortality, percentage of liver ether extract or egg shell breaking strength. Percentage of body ether extract tended to be lower when pine shavings were fed.     

脂肪粉对蛋鸡生产性能及相关理化指标的影响

为探讨饲料中添加脂肪对蛋鸡生产性能的影响,选择300日龄褐壳蛋鸡720只,随机分为3个处理,每个处理分为6个重复;试验组分别添加1％、2％脂肪粉,观测其对蛋鸡生产性能、生理变化及经济效益的影响。结果表明：添加脂肪,可以明显提高（P〈0．05）蛋鸡产蛋率（3．51～5．23％）和蛋重（6．03～8．69％）,降低采食量（3．63～3．67％）,改善饲料报酬（13．08～16．03％）;生理指标检测结果显示,试验组血清T3、T4含量显著提高（P〈0．05）,并且有提高GH、IGF－1含量趋势（P〉0．05）;综合经济效益分析,添加脂肪可以提高蛋鸡养殖效益（16．67～26．98％）。因此,杂粕型蛋鸡饲料中添加脂肪有实际意义。     

Effects of lighting regimen and grower diet energy concentration on energy expenditure,fat deposition and body weight gain of laying hens

1. Mean metabolisable energy (ME) intakes and heat productions over a laying year were calculated for laying hens which had been submitted to one of various lighting regimens and given either a normal or a high energy ration during the rearing period.

2. Daily ME intake and heat production per hen in the laying period were unaffected by either lighting regimen or grower diet. ME intake per kg W ^0.75 and heat production per kg W ^0.75 during lay increased significantly with laying photoperiod, was non‐significantly higher following an 8‐h rather than an 11‐h rearing photoperiod, but was unaffected by dietary energy concentration. The increase in heat production (/kgW°‘⁷⁵) associated with a 1‐h increment in photoperiod was similar to predictions made from calorimetric measurements of diurnal variation.

3. Efficiency of conversion of food to egg was unaffected by either lighting regimen or dietary energy concentration.

4. Fat weight gain in lay was not influenced by lighting regimen, but was significantly lower in birds reared on the high, compared to the normal, energy grower ration. Fat‐free weight gain in lay was unaffected by grower diet, but was significantly increased by photoperiods longer than 8 h.

5. ME intake and heat production per kgW^⁰⁷⁵ were negatively correlated with age at first egg, but ME intake and heat production per bird d were not related to age at sexual maturity.     

Effect of dietary ascorbic acid on the performance of laying hens under warm environmental conditions

Two trials were conducted to investigate the effects of dietary ascorbic acid (AA) on the performance of laying hens maintained under high environmental temperatures (32.2 °C and 33.3 °C, respectively), and a third trial was carried out under ambient conditions (12.8 °C to 17.3 °C).

Weekly changes in egg yield, shell deformation, percentage of cracked eggs and body weight showed an improvement in the AA‐supplemented birds but the differences were non‐significant. Egg yield and percentage of cracked eggs were not affected when the diet was supplemented with AA under ambient conditions.     

Effect of dietary xylanase on energy, amino acid and mineral metabolism, and egg production and quality in laying hens

1. The aim was to examine the effect of dietary xylanase on the availability of nutrients for laying hens when fed on wheat-rye-soy-based diets. The basal diet was formulated to contain 11.03 MJ/kg apparent metabolisable energy (AME), and the experimental diets were formulated by supplementing the basal diet with four different activities of xylanase (400, 800, 1200 and 1600 xylanase units (XU)/kg). 2. The AME and nitrogen metabolisability coefficients of xylanase-supplemented diets were 1.2% and 7.1%, respectively, greater than in the control diet. 3. Supplementary xylanase significantly improved the coefficients of metabolisability of indispensable, dispensable and total amino acids by 8.2%, 6.9% and 7.8%, respectively, and led to a significantly linear response of total amino acid metabolisability coefficient to xylanase. There was a range of effects within the indispensable amino acids with xylanase supplementation (1600 XU/kg) significantly improving the metabolisability of threonine by 4.9%, but having no have effect on lysine. The response of total amino acid retention to added xylanase was a significant quadratic function and suggests that 800 XU/kg is the optimum supplementary dosage. 4. Supplementary xylanase significantly improved sulphur metabolisability in a linear fashion to a maximum of 2.3% higher than that of the control diet. In terms of daily retention, most of the minerals responded in a quadratic manner to dietary xylanase, as the suggested optimal supplementary level was between 800 and 1200 XU/kg. 5. The yolk colour of the birds receiving 1200 and 1600 XU/kg was 0.33 and 0.28 units (Roche score); these were 4.1% and 3.5%, respectively, darker than the yolk of the birds given the control diet. 6. Birds receiving xylanase had a significantly higher weight gain than those fed on the unsupplemented diet. Feed intake, the number of eggs per hen per d, dirty and cracked eggs, and feed conversion ratio for egg production were not affected by xylanase. These data suggest that use of a xylanase may improve the metabolisability of many nutrients, but that such effects may not always benefit production parameters.     

Influence of dietary osteolathyrogenson the eggshell quality of laying hens

1. Laying hens were fed osteolathyrogens, either semicarbazide hydrochloride at 0.3 or 0.4 g/kg or β-aminopropionitrile fumarate at 0.5 or 0.6 g/kg diet to examine their effects on eggshell quality. 2. Shell quality characteristics considered for evaluation were shell surface area, shell thickness, shell weight, percentage shell, shape index and the specific gravity of eggs. Measurement of shell quality traits revealed that the hens fed osteolathyrogens laid eggs with significantly lower specific gravities and proportion of shell by weight. These differences were not explained by differences in shell thickness or weight or the shape index of eggs. 3. It was concluded that osteolathyrogens cause hens to lay eggs with poor shell quality and such eggs are weak and fragile.     

日粮维生素水平对生长期蛋鸡影响的研究

选用4因素3水平正交试验设计，研究日粮维生素A、D3、E对生长期蛋鸡的影响。结果如下：6周末体重随VE水平的提高而提高，但差异不显著。14周末体重受VE的显著影响。高水平（100mg／kg）组显著大于低水平（10mg／kg）组与中水平（40mg／kg）组（P＜0．01），中、低水平之间差异不显著。血清新城疫抗体效价随VA水平的提高而显著提高（P＜0．05）。高水平VA和高水平VE组合组显著高于其它组（P＜0．05）。胫骨中的钙含量随VA水平的提高显著提高（P＜0．01）。VD3对体重、抗体滴度和胫骨Ca含量无显著影响。     

Influence of dietary calcium and phosphorus on metabolism and production in laying hens

1. The effects of different dietary concentrations of calcium (24 to 56.9 g/kg) and phosphorus (4.5 to 14.2 g/kg) on production and some aspects of metabolism were studied in laying hens.

2. Treatments did not affect egg numbers, food consumption, conversion efficiency of food to egg, bodyweight gain or mortality.

3. Increasing dietary calcium (Ca) significantly increased plasma Ca and inorganic phosphorus (P), breaking strength at the radius and egg specific gravity and significantly decreased plasma alkaline phosphatase and egg weight.

4. Increasing dietary phosphorus increased plasma P and decreased egg specific gravity significantly.

5. Plasma Ca, P and alkaline phosphatase and radius breaking strength were suitable indices of the Ca status of the hens.     

维生素E水平和免疫应激处理对蛋鸡生产性能的影响

试验旨在研究维生素E水平和免疫应激对蛋鸡生产性能的影响。采用3×3双因子设计,270只19周龄健康来航蛋鸡随机分为9组,每组5个重复,每重复6只鸡。其中,3个日粮VE水平分别为0、40和100IU/kg,3种免疫应激方式分别为不注射、肌注生理盐水和肌注减蛋综合症疫苗。结果表明:VE对免疫应激给鸡群生产性能带来的不良影响具有部分缓解作用,在免疫应激状态下,鸡群对于VE的营养需求量增加。