Comparison between wheat, triticale, rye, soyabean oil and strain of laying bird on the production, and cholesterol and fatty acid contents of eggs.

1. The effects of feeding three types of cereal grain (wheat, triticale or rye) and soyabean oil (0 or 20 g/kg) over a 12-week period on the production, yolk cholesterol and yolk fatty acid concentrations of three strains of laying pullets were studied. 2. Pullets fed on wheat- or triticale-based diets had higher body weight gains, egg productions, egg weights, egg mass and lower yolk cholesterol concentrations than pullets fed on rye-based diets. However, there were no significant differences between the cereals in yolk cholesterol content. 3. There were no significant differences between the three cereals in total food consumption of pullets nor of yolk weight nor yolk concentration of palmitic, stearic and oleic acids. 4. Pullets fed on triticale-based diets had higher yolk linoleic acid concentrations and lower yolk oleic acid: linoleic acid ratios than pullets fed on rye- or wheat-based diets. 5. Soyabean oil supplementation increased egg production, egg mass, yolk linoleic concentration and yolk unsaturated to saturated fatty acid ratio, but reduced yolk oleic acid: linoleic acid ratio. 6. There were differences between strains of pullets in weight gain, food consumption, rate of lay, egg weight and yolk cholesterol, but not in yolk fatty acid concentrations. 7. It was concluded that wheat- or triticale-based diets gave good production of eggs of lower cholesterol content, that soyabean oil supplementation gave eggs with a high unsaturated to saturated fatty acid ratio and that two strains of layers produced eggs with lower yolk cholesterol concentrations than a third strain.     

鸡蛋暗斑对蛋品质及抗氧化能力的影响

[目的]研究鸡蛋暗斑对蛋品质及其抗氧化能力的影响。[方法]从饲喂同种日粮、饲养环境相同、同日龄褐壳蛋鸡同一批次所产的褐壳蛋中,用灯光照射法挑选出24枚典型正常蛋、24枚典型暗斑蛋进行试验,并分别对正常蛋和暗斑蛋进行蛋品质、蛋黄抗氧化指标的测定及比较。[结果]蛋品质比较:暗斑蛋与正常蛋相比,其蛋形指数、蛋壳强度、蛋重、哈氏单位、蛋白高度、鸡蛋等级、蛋黄颜色、蛋黄重、蛋壳重、蛋清重、蛋壳厚度、蛋黄比重、蛋壳比重、蛋清比重均差异不显著(P>0.05);暗斑蛋蛋壳颜色极显著深于正常蛋(P<0.01)。抗氧化指标比较:暗斑蛋蛋黄的总抗氧化能力(T-AOC)显著低于正常蛋蛋黄的总抗氧化能力(P<0.05),暗斑蛋蛋黄的丙二醛(MDA)含量与正常蛋蛋黄的丙二醛含量相比差异不显著(P>0.05)。[结论]与正常蛋相比,暗斑蛋的蛋壳颜色较深,总抗氧化能力较差。     

高棉籽粕饲粮对蛋鸡生产性能及蛋品质的影响研究

为了研究高棉籽粕饲粮对蛋鸡生产性能及鸡蛋品质的影响,试验选用26周龄海赛克斯褐蛋鸡60只,随机分为试验组和对照组,试验组饲喂30%的棉籽粕,为期28d,研究高棉籽粕饲粮对蛋鸡生长性能、蛋品质以及对鸡蛋储存后品质的影响。结果表明:①高棉籽粕饲粮对蛋鸡生产性能、鸡蛋常规品质没有显著影响(P>0.05)。②采用物性分析仪测定鸡蛋弹性,当天产新鲜鸡蛋没有出现弹性,经4℃贮藏7d后开始出现弹性,即出现所谓的"橡皮蛋",14d鸡蛋弹性最为明显。经贮藏2周后,试验组鸡蛋蛋黄、蛋白色泽没有变化,无褐色斑点。     

Effects of supplementary iodine on the performance and egg traits of laying hens

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.     

不同储藏方式对鸡蛋品质的影响

 为探讨夏季常温保存和低温冷藏两种储藏方式对鸡蛋品质的影响,选择540个鸡蛋随机分为9组,1组当天测定蛋品质,3组置于28.31 ℃、湿度为68.13%的室温下保存,5组置于4~8 ℃的冷藏室保存,分别于第7、14、21、42和56 d测定蛋品质。结果表明,常温储藏的鸡蛋随着存放时间延长,鸡蛋品质不断下降,储藏21 d后,蛋重降低5.30%（P<0.05）,蛋壳厚度变薄（P<0.05）;哈氏单位随着储藏时间的延长迅速下降,第0 d比第21 d的哈氏单位值高59.18%（P<0.05）;蛋黄比率随储藏时间的延长有不断变大的趋势,第0 d的蛋黄比率比第21 d低15.58%（P<0.05）。低温冷藏的鸡蛋储藏到21 d时,仅哈氏单位比第0 d低6.78%（P<0.05）;冷藏到56 d时,蛋重和哈氏单位比第0 d分别降低5.63%和15.07%（P<0.05）,蛋黄比率提高了5.21%（P<0.05）。试验表明,鸡蛋在室温下的新鲜度适宜保存期不应超过21 d;低温冷藏时可以保存到56 d。     

不同周龄母鸡鸡蛋及不同蛋壳质地鸡蛋的蛋品质比较

本文比较了同一品种不同周龄(26、40周龄和64周龄)母鸡所产蛋的蛋壳品质和蛋品质,包括蛋重、蛋壳相对重、蛋形指数、蛋壳强度、蛋壳厚度、蛋黄颜色、蛋黄指数、蛋黄比率、哈氏单位、蛋清pH值。之后,还比较了该鸡种不同蛋壳质地鸡蛋(正常蛋和砂壳蛋)之间上述指标的差异。结果表明:在不同周龄母鸡所产蛋之间,蛋重、蛋黄指数、蛋黄比率、哈氏单位等均存在显著差异(p<0.05),而蛋壳厚度之间差异不显著(p>0.05)。此外,蛋重、蛋形指数、蛋黄颜色、蛋黄比率随着母鸡周龄的增加呈上升趋势,而蛋壳强度、蛋壳相对重、哈氏单位、蛋黄指数、蛋清pH值呈下降趋势。最后,蛋壳质地不同的鸡蛋(正常蛋与砂壳蛋)之间,蛋重、蛋壳相对重、蛋壳强度、蛋清pH值之间存在极显著差异(p<0.01),而其他参数之间差异不显著(p>0.05)。     

太行鸡与矮脚麻鸡蛋品质比较研究

随机抽取214日龄的引入品种矮脚麻鸡与河北本地品种太行鸡种鸡鸡蛋各100枚,分别测定蛋重、蛋形指数、蛋比重、蛋黄颜色、哈氏单位、蛋黄比率、蛋壳厚度、蛋壳强度、血肉斑比率。结果表明:二品种鸡蛋品质在蛋重、蛋比重、蛋黄颜色、蛋壳厚度方面无显著性差异(P>0.05);哈氏单位、蛋黄比率差异极显著(P<0.01);蛋形指数、蛋壳强度差异显著(P<0.05)。     

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.     

缠丝鸭蛋蛋品质及营养成分测定

为研究缠丝鸭蛋和普通鸭蛋在蛋品质及营养成分之间的差异,本试验随机选取300日龄左右鸭产的缠丝鸭蛋和普通鸭蛋各50枚,分别测定其蛋重、蛋壳厚度、蛋壳强度、蛋壳颜色、蛋白高度、蛋形指数、蛋黄色泽和哈氏单位等蛋品质性状及粗蛋白质、粗脂肪、钙、磷、锌和铁等营养成分含量。结果表明,与普通鸭蛋相比,缠丝鸭蛋的蛋重、蛋壳厚度、蛋壳颜色、蛋壳强度和蛋形指数差异均不显著(P>0.05),而蛋白高度、蛋黄色泽和哈氏单位极显著高于普通鸭蛋(P<0.01);蛋白质、钙、锌、铁含量较高,脂肪、磷含量较低。提示,缠丝鸭蛋蛋品质优于普通鸭蛋,营养物质含量比普通鸭蛋更丰富。     

Effect of yeast cell wall supplementation in laying hen feed on economic viability,egg production,and egg quality

Yeast cell walls can strengthen the immune system and promote agglutination of gastrointestinal tract pathogens, thereby improving animal health and productivity. This study evaluated the effect of supplementing the diet of commercial laying hens with 0, 225, 450, or 900 ppm of yeast cell wall supplement on hen productive performance, egg quality, and economic viability. Yeast cell wall supplementation increased the feed intake, egg production, egg mass, albumen height, and Haugh unit score. Shell thickness and yolk color also were affected by the treatments. The economic viability analysis demonstrated that although feeding costs more with supplementation, the production of more eggs is possible, resulting in a greater than proportional increase in the gross margin. Thus, yeast cell wall supplementation had beneficial effects on the productive performance of laying hens, improved the internal and external egg quality, and contributed to greater profitability.     

Genetic parameters of the thick-to-thin albumen ratio and egg compositional traits in layer-type chickens

ABSTRACT

1. Generating a robust egg albumen is one of the major factors contributing to interior egg quality owing to its nutritive value and superior appearance. However, the genetic factors regulating the proportion of thick albumen are poorly understood.

2. In this study, 1330 eggs were collected from 450 Rhode Island White layers, aged 40 weeks, to measure egg compositional traits for three successive days. The restricted maximum likelihood method was applied to estimate genetic parameters for the thick-to-thin albumen ratio and other egg compositional traits. A univariate animal model was fitted to calculate heritability for each trait.

3. The heritabilities of egg weight, yolk weight, albumen height, Haugh units, percentages of yolk, thick albumen, thin albumen and the thick-to-thin albumen ratio were 0.32, 0.34, 0.28, 0.47, 0.61, 0.39, 0.31, and 0.45, respectively. The percentage of thick albumen was negatively correlated genetically with all traits, and percentage of thin albumen was negatively correlated genetically with all traits except for Haugh units. The thick-to-thin albumen ratio was positively correlated genetically with egg weight, albumen height and Haugh units, with correlations ranging from 0.21 to 0.54.

4. The results indicated that the percentage of thick albumen and the thick-to-thin albumen ratio were found to be moderately to highly heritable, and selection for the thick-to-thin albumen ratio could be conducive to the improvement of egg albumen quality.     

Effects of Chinese herbal mixture on performance,egg quality and blood biochemical parameters of laying hens

The aim of the study was to evaluate the effect of Chinese herbal mixture (CHM) in laying hen diets on performance, egg quality and egg nutrition components, as well as selected blood biochemical parameters. A total of 270 Lohmann Brown laying hens, 24 week of age, were randomly distributed into three dietary treatments and fed for 6 week. The CHM was used at the levels of 0%, 0.5% and 1.0% in the diets of the control and two treatment groups respectively. Each dietary treatment was divided into five replicates, comprising of 18 hens each. Hens were housed in a 3‐tier battery system. Feed and water were provided ad libitum. Blood samples and eggs were collected at the end of the experiment. The results showed that dietary treatments did not affect egg weight, mortality, eggshell thickness, albumen height, Haugh units, eggshell‐breaking strength and egg‐shape index. Dietary supplementation of CHM significantly improved (p < 0.05) laying rate and the lowest feed conversion ratio were observed with 1.0% CHM supplementation diets. CHM supplementation decreased (p < 0.05) cracked‐egg rate, egg yolk cholesterol, blood serum levels of cholesterol, triglyceride, low‐density lipoprotein cholesterol (LDL‐C) and alanine aminotransferase (ALT) and increased blood serum levels of high‐density lipoprotein cholesterol (HDL‐C). No differences in serum total protein, serum albumen, serum glucose and aspartate amino transferase (AST) were observed in hens fed CHM. In conclusion, dietary supplementation with CHM improved egg production and egg quality and reduced serum cholesterol concentrations in laying hens. Dietary supplementation of 1.0% CHM in layer diets may be a feasible means of producing eggs with lower cholesterol and higher egg yolk phospholipid contents for health conscious consumers.     

A comparison of measured and estimated haugh units with factors affecting their differences

A total of 1800 eggs was examined by four experienced inspectors who estimated the Haugh unit value of each egg by candling. The eggs were of two different ages and were presented in random order to each inspector. On subsequent breaking out of the eggs the Haugh units values were measured, together with the shell thickness and yolk colour. Relations between the inspectors’ estimated Haugh unit values, the measured values, and the other factors were then examined statistically. It was found that the age of egg affected the inspectors estimates’ errors (the differences between their estimates and the measured values), as, to lesser extents, did the yolk colour and the shell thickness.

While consistent patterns appeared in the “ errors “ of each inspector, their estimates of Haugh units values had low correlations (generally about 0–5) with the measured values, and similar correlations with each other. Thus it appeared that while they were trying to evaluate quality by different criteria from the measured values, they were also to some extent inconsistent with each other in their judgements.     

笼养与平养蛋鸭蛋品质测定与相关性分析

试验旨在比较笼养和平养方式对不同品种蛋鸭蛋品质的影响,以期为评价不同饲养方式下的鸭蛋品质提供参考依据。随机选取40周龄笼养和平养的金定鸭（青壳蛋）和山麻鸭（白壳蛋）鸭蛋各30枚于产后24 h内进行蛋品质测定。结果表明,同一品种笼养蛋鸭蛋重极显著大于平养蛋鸭蛋重（P<0.01）,蛋重与蛋壳重、蛋白重和蛋黄重之间均存在极显著正相关（P<0.01）,但不同类型鸭蛋的蛋黄重之间差异不显著（P>0.05）。青壳蛋的蛋壳强度显著高于白壳蛋（P<0.05）,笼养青壳蛋的蛋壳强度亦高于平养青壳蛋（P<0.05）。蛋的比重与蛋壳厚度呈极显著正相关（0.503,P<0.01）,与蛋壳强度的相关系数亦达到0.536（P<0.01）。4种类型鸭蛋的哈氏单位均达到72以上。虽然蛋白重与蛋黄重之间呈极显著正相关（P<0.01）,但蛋白重与蛋黄比率之间却呈极显著的负相关（P<0.01）。蛋的比重与蛋黄重和蛋黄比率之间亦存在显著负相关（P<0.05）。以上结果表明,就蛋品质而言,蛋鸭养殖以采用笼养模式、选择青壳蛋鸭品种为宜。     

鹅蛋与鸭蛋生物学特性的比较

作者旨在研究地方品种鹅蛋与鸭蛋的生物学特性差异。同期采集固始白鹅种蛋56枚,淮南麻鸭种蛋64枚,对外部特征和内部品质进行对比。结果表明二者之间存在较大差异,鹅蛋与鸭蛋各指标分别为：蛋重（159.1 g,62.17 g）、蛋比重（1.119,1.094）、蛋壳厚度（0.514 mm,0.311 mm）、哈氏单位（107.77,86.14）、蛋黄比例（38.12%,30.28%）、蛋壳比例（12.32%,11.19%）,以上指标鹅蛋均高于鸭蛋。鸭蛋蛋黄色泽优于鹅蛋,罗氏比色鸭蛋、鹅蛋分别为11.33和4.52。鸭蛋的血肉斑率达到12.5%,明显高于鹅蛋的3.57%,需要通过育种手段来降低。     

舍饲与林地放养混合模式下寿光鸡、固始鸡和罗曼蛋鸡蛋品质及肉品质的比较

本试验旨在比较寿光鸡、固始鸡和罗曼蛋鸡在舍饲与林地放养混合模式下蛋品质及肉品质的差异。选取90日龄寿光鸡、固始鸡和罗曼蛋鸡母鸡各120只,每个品种鸡设4个重复,每个重复30只,在舍饲与林地放养混合模式下采用常规基础饲粮饲喂至180日龄。结果表明:罗曼蛋鸡与寿光鸡、固始鸡相比,蛋重显著升高(P0.05),而蛋黄颜色、蛋白高度和哈氏单位显著降低(P0.05)。寿光鸡和固始鸡的蛋中锌、硒、钙、蛋白质和脂肪含量较罗曼蛋鸡显著升高(P0.05),肌肉中脂肪和蛋白质含量也较罗曼蛋鸡显著升高(P0.05)。寿光鸡、固始鸡肌肉的滴水损失率、剪切力显著低于罗曼蛋鸡(P0.05),肉色显著高于罗曼蛋鸡(P0.05)。寿光鸡和固始鸡肌肉中甘氨酸、谷氨酸、异亮氨酸和鲜味氨基酸含量显著高于罗曼蛋鸡(P0.05)。总之,寿光鸡和固始鸡的蛋具有大蛋黄、高蛋白,且营养元素丰富,而罗曼蛋鸡的蛋含水量较高,蛋白质品质较差;寿光鸡和固始鸡的肌肉较罗曼蛋鸡具有较长货架期,且肌苷酸和氨基酸含量高,肉质鲜嫩,营养丰富;3个品种鸡中,寿光鸡和固始鸡的蛋品质和肉品质更佳。     

Use of L-carnitine and humate in laying quail diets

This experiment was carried out to determine the effects of using L-carnitine and humate alone or in combination in quail diets on laying performance, egg traits and blood parameters. A total of 280 Japanese quails aged 10 weeks, divided into one control group and three treatment groups, were used. The diets of the first, second and third treatment groups were supplemented with 100 mg L-carnitine/kg, 1.5 g humate (Farmagülat?r Dry Plus)/kg and 100 mg L-camitine + 1.5 g humate/kg, respectively. The experimental period lasted 16 weeks. The addition of L-carnitine and sodium humate alone or in combination did not significantly affect body weight, feed consumption, egg production, feed conversion ratio, mortality, egg-shell thickness, egg yolk index and the percentages of egg-shell, albumen and yolk. Egg weight increased (P < 0.001) with L-carnitine supplementation. The values of egg albumen height (P < 0.05), egg albumen index (P < 0.01) and egg Haugh unit (P < 0.05) were increased with humate supplementation. Egg cholesterol content and blood serum parameters were not affected by the supplementation of L-carnitine with or without humate. The results in this study demonstrated that L-carnitine supplementation increased egg weight while humate addition increased egg albumen index and egg Haugh unit of laying quails. However, the combined administration of L-carnitine and humate did not have any significant effects on the parameters measured.     

松针粉对蛋鸡生产性能、蛋品质、血清生化指标和抗氧化指标的影响

试验旨在研究松针粉对蛋鸡生产性能、蛋品质、血清生化指标和抗氧化指标的影响,以期为松针粉在蛋鸡生产中的应用提供参考。选用120羽40周龄健康产蛋期京粉1号蛋鸡作为试验动物,随机分为2组,每组6个重复,每个重复10羽鸡。对照组饲喂基础饲粮,试验组用3%松针粉替代基础饲粮中的小麦麸。预试期7 d,正试期56 d。试验期间,每天按重复记录采食量、产蛋总数、总蛋重等,并以组为单位统计其平均日采食量、平均蛋重、日产蛋量、料蛋比等;在正试期第28和56天,分别从各重复中取2枚鸡蛋测定蛋壳强度、蛋壳厚度、蛋黄颜色、哈夫单位;在试验结束前1 d和结束当天,从各重复中抽取10枚鸡蛋于4℃贮藏,每次从各重复中取2枚鸡蛋,测定其贮藏后第15、20、60、105天的哈夫单位;在正试期第56天从各重复中选取试验蛋鸡1只,空腹12 h后经翅下静脉采血5 mL后分离血清,采用全自动生化仪测定血清中总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）、总蛋白（TP）、白蛋白（ALB）、尿酸（UA）、尿素（Urea）、葡萄糖（GLU）含量及丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、碱性磷酸酶（ALP）活性;采用试剂盒法测定血清中丙二醛（MDA）含量、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、谷胱甘肽（GSH）、过氧化氢酶（CAT）的活性和总抗氧化能力（T-AOC）。结果显示：①与对照组相比,饲粮中添加松针粉显著提高了蛋鸡产蛋率（P<0.05）,显著降低了平均蛋重和料蛋比（P<0.05）,但平均日采食量、平均日产蛋量和合格蛋率均无显著差异（P>0.05）。②试验第28天,试验组蛋黄颜色值显著高于对照组（P<0.05）,试验第56天,两组间蛋黄颜色值差异不显著（P>0.05）;其余时间点,饲粮中添加松针粉对鸡蛋的哈夫单位、蛋壳厚度和蛋壳强度均无显著影响（P>0.05）。③与对照组相比,饲粮中添加松针粉对蛋鸡血清TC、TG、HDL-C、LDL-C、TP、ALB、球蛋白（GLB）、尿素、UA和GLU含量以及ALT、AST、ALP活性均无显著影响（P>0.05）,显著提高了蛋鸡血清MDA含量和GSH-Px活性（P<0.05）,但对GSH含量和SOD、CAT活性以及T-AOC均无显著影响（P>0.05）。综上所述,饲粮中添加3%松针粉能够显著提高蛋鸡产蛋率,改善料蛋比和蛋黄颜色,显著提高蛋鸡血清MDA含量和GSH-Px活性,但未影响机体T-AOC。因此,蛋鸡饲粮中用3%松针粉替代等比例的小麦麸是可行的。     

Determination and Correlation Analysis on the Egg Quality of Egg-laying Ducks Reared in Cages and on Floor

The purpose of this test was to evaluate the egg quality from two breeds of ducks reared in cages and on floor.30 eggs were chosen from each type of eggs,which were from Jinding (green shell) and Shan Partridge ducks (white shell)at 40 weeks-old reared in cages and on floor for egg quality evaluation.The results showed that the egg weight of caged duck was extremely significantly larger than the floor duck (P<0.01) in the same breed,there were very significant positive correlations between the egg weight and eggshell weight,egg-white weight and egg yolk weight (P<0.01),but no significant difference among the egg yolk weights of different types of ducks (P>0.05).The shell strength of green egg was obviously higher than that of white shell eggs (P<0.05),and the shell strength of green egg from caged ducks was higher than that of the green egg ducks on floor.The correlation coefficients of the egg specific gravity and eggshell thickness,the specific gravity and eggshell strength were 0.503 (P<0.01) and 0.536 (P<0.01) respectively.Haugh units of four types of ducks all reached 72 or more.Although there was significant positive correlation between egg-white weight and egg yolk weight (P<0.01),significant negative correlation was existed between egg-white weight and egg yolk ratio (P<0.01).There were significant negative correlations between egg specific gravity and egg yolk weight (P<0.05) and egg yolk ratio (P<0.05).In conclusion,the mode of cage feeding and the breed with green shell were appropriate choices in laying-egg duck production for high egg quality.     

Effect of fructooligosaccharides and antibiotics on laying performance of chickens and cholesterol content of egg yolk

1. Nine hundred and sixty 25-week-old Lohmann Brown layers were randomly divided into 5 groups with 216 layers in each group. Layers in group one were fed a control diet, group 2 received the control diet plus 20 mg/kg zinc bacitracin and 4 mg/kg colistinsulfate, and the remaining three groups received control diet plus 2000, or 4000, or 6000 mg/kg fructooligosaccharide (FOS). 2. The results showed improvements in egg production, feed consumption and feed conversion of layers when 2000 mg/kg FOS was added to the diets. 3. The results also showed some additional improvements in the group supplemented with 2000 mg/kg FOS, including increases in egg shell thickness, yolk colour and Haugh unit, and decreases in yolk cholesterol concentration. 4. However, larger (excessive) doses of FOS did not improve the performance of layers.