Effects of dietary red pepper on egg yolk colour and histological intestinal morphology in laying hens

To evaluate the effect of three kinds of red pepper supplementation ‘Kagawa Hontaka’ produced at Shiwaku Islands (KHS), Miki (KHM) and Takanotsume (TKT) on production performance, egg quality and intestinal histology in laying hens. A total of 32 laying hens (39 weeks of age) were randomly allotted to four groups, each comprising eight hens. Birds were fed a basal diet supplemented with red pepper at 0% (control), 0.5% KHS, 0.5% KHM and 0.5% TKT, respectively. Compared with the control group, no significant difference (p > 0.05) in feed consumption, final body weight, hen‐day production, egg mass, feed efficiency, shell‐breaking strength, shell thickness, shell ratio, albumen ratio, yolk ratio and Haugh units was observed among the experimental groups. Roche yolk colour fan (RYCF) value increased significantly in all experimental groups (p < 0.05). Furthermore, the KHS and KHM groups showed higher RYCF values than the TKT group (p < 0.05). Spectrophotometric measurements of yolk colour, redness (a*) and yellow index (YI) values were higher in the KHS and KHM groups (p < 0.0001). The yellowness (b*) value was lower in the TKT group (p < 0.05). The lightness (L*) value was lower in the KHS and KHM groups (p < 0.05). Villus height, villus area, cell area and cell mitosis in all intestinal segments tended to be higher in all experimental groups. Jejunal cell area and cell mitosis were higher in experimental groups than in the control group (p < 0.05). The cells on the villus tip surface were protuberated in all experimental groups. In conclusion, the KHS, KHM and TKT groups showed hypertrophied intestinal villi and epithelial cell functions. These results indicate that dietary red pepper has stimulating effect on intestinal villi and the structure of epithelial cells, and the 0.5% KHS and KHM groups improved in egg yolk colour.     

Astaxanthin Z-isomer-rich diets enhance egg yolk pigmentation in laying hens compared to that in all-E-isomer-rich diets

The effects of feeding diets containing astaxanthin with different Z-isomer ratios to laying hens on egg qualities, such as astaxanthin concentration in egg yolk and yolk color, were investigated. As the astaxanthin source, a natural microorganism Paracoccus carotinifaciens was used. Astaxanthin with different Z-isomer ratios was prepared by thermal treatment with different conditions and then added to the basal diet at a final astaxanthin concentration of 8 mg/kg. We found that, as the Z-isomer ratios of astaxanthin in the diet increased, the astaxanthin concentration in egg yolk and the yolk color fan score also increased significantly. Importantly, feeding a 50.6% Z-isomer ratio diet increased astaxanthin concentration in egg yolk by approximately fivefold and the color fan score by approximately 2 compared to that in hens fed an all-E-isomer-rich diet. Moreover, we showed that feeding Z-isomer-rich astaxanthin to laying hens increased plasma astaxanthin concentration by more than five times in comparison to that in hens fed an all-E-isomer-rich diet. These results indicate that Z-isomers of astaxanthin have higher bioavailability than that of the all-E-isomer and thus they exhibit greater egg yolk-accumulation efficiency.     

Effects of vitamin E supplementation on performance,serum biochemical parameters and fatty acid composition of egg yolk in laying hens fed a diet containing ageing corn

This study investigated whether dietary vitamin E (VE) supplementation could alleviate any detrimental effects of ageing corn in the diet for laying hens on egg performance, egg quality, serum biochemical parameters, cholesterol content and the fatty acid (FA) profile of egg yolks. The experiment consisted of a 2 × 3 factorial design with two corn types (normal corn and ageing corn) and three concentrations of VE (0, 20 and 100 IU/kg). A total of 216 Lohmann laying hens (50‐week‐old) were randomly allocated into six treatment diets for 12 week. Each treatment had six replicates with six hens. The results showed that ageing corn significantly reduced average daily feed intake (ADFI; p < 0.01) and egg weight (p < 0.05). Dietary VE supplementation had no significant influences on egg production performance (p > 0.05). Egg yolk colour was decreased in ageing corn diets (p < 0.01), while 20 and 100 IU/kg VE significantly improved vitelline membrane strength (p < 0.01) compared with feeding of 0 IU/kg VE. Ageing corn also significantly decreased the content of cholesterol including total cholesterol (TC; p < 0.05), low density lipoprotein cholesterol (LDL‐C; p < 0.01) and very low density lipoprotein cholesterol (VLDL‐C; p < 0.05) in the serum. Feeding 100 IU/kg VE significantly increased the content of LDL‐C (p < 0.01) and VLDL‐C (p < 0.05) in the serum. Furthermore, the content of the oleic acid, docosahexaenoic acid and total monounsaturated fatty acid (MUFA) was lower (p < 0.05) and stearic acid and total saturated fatty acid (SFA) was higher (p < 0.05) in egg yolks in ageing corn diets. Ageing corn resulted in reduced feed intake, egg weights and yolk colour, but the effects of VE supplementation were independent of those of age of corn and were unable to counteract the negative effects of feeding ageing corn.     

维生素E对蛋鸡产蛋后期产蛋性能和蛋品质的影响

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 m...     

The effects of formic acid-treated shrimp meal on laying performance and egg quality in aged laying hens

An experiment was carried out to measure the suitability of using formic acid-treated shrimp meal (TSM) as a protein source for aged laying hens. Shrimp meal (SM), air-dried shrimp waste was treated with 3% formic acid (w/v) at room temperature for 20 min, sun-dried, ground to pass through 1.0 mm mesh screen and then ready to use as the TSM. A total of 56 Single Comb White Leghorn hens, 85 wk of age, were placed in individual cages and assigned randomly into 7 dietary groups of 8 birds each. A control diet, diets containing 5, 10, and 15% SM and diets containing 5, 10, and 15% TSM were prepared. Diets and water were given ad libitum during the 30-d experimental period. Hen-day egg production, egg mass, feed intake, and feed conversion ratio (FCR) were deteriorated with increasing levels of the SM in the diets (P < 0.05). In contrast, these parameters were unchanged with increasing levels of the TSM in diets and compatible with the control group. No significant improvements were observed in exterior or interior egg quality among the dietary groups, except for eggshell weight, strength and yolk color, which were significantly increased in SM and TSM groups when compared to the values in control group (P < 0.05). It is concluded that inclusion of TSM up to 15% in laying hen diets may have beneficial effects on laying performance along with improved eggshell quality and yolk color, and suggested that TSM is a promising combined source of protein and calcium in aged laying hens.     

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.     

鲜茶叶粉对蛋鸡生产性能、蛋品质、蛋黄脂肪酸水平及经济指标的影响

文章旨在评估日粮添加不同水平的鲜茶叶粉对蛋鸡生产性能、蛋品质及蛋黄脂肪酸水平的影响.试验将672只产蛋性能一致的28周龄海兰褐壳蛋鸡随机分为4组,每组4个重复,每个重复42只.对照组饲喂基础日粮,处理组蛋鸡分别饲喂基础日粮+20(T1)、40(T2)和60?mg/kg(T3)鲜茶叶粉,试验为期6周.结果:与对照组相比,...     

维生素E对免疫抑制产蛋鸡生产性能和蛋品质的调控效应

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。     

Influence of sumac (Rhus Coriaria L.) and ginger (Zingiber officinale) on egg yolk fatty acid,cholesterol and blood parameters in laying hens

The aim of the study was to evaluate the potential effect of different levels of sumac (Rhus coriaria L.) seed powder and ginger (Zingiber officinale) root powder on egg yolk fatty acid composition, blood/yolk cholesterol in laying hen. A total of 63 (ATAK‐S: Domestic Turkish Laying Hens) laying hens (average weight: 1470 g each hen, 25‐weeks of age) were assigned to seven treatment diets including sumac seed (S) and ginger root powder (G) at 0 g/kg (control), 10 g/kg (S1), 20 g/kg (S2), and 30 g/kg (S3); 10 g/kg (G1), 20 g/kg (G2), or 30 g/kg in rations respectively, for 8 weeks. After a two‐week adaptation period to cages, the hens were allocated to 7 groups with 9 replicates of 1 hen in per cage each. The replications were allotted equally into the upper and lower cages to minimize the effects of cage level. In this study, egg yolk cholesterol had a decrease (p <0.05) in supplemented diet( sumac seed and ginger root powder). Fatty acid content in yolk; saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acids and rate of n6/n3 were not significant (p <0.05). However, dietary supplementation with sumac and ginger powder reduced and yolk/blood cholesterol concentrations in laying hens. Supplementation of sumac and ginger affected on HDL, there was found a significant effect (p < 0.05) in treatment groups. Moreover, LDL positively decreased in all treatment groups compared with the control group. The findings of this study suggested that feeding sumac and ginger tend to be decreasing cholesterol levels in both yolk and blood on laying hens. It can be concluded that ginger root and sumac seed powder can be used as an effective feed additive to improve fatty acid composition and yolk and blood cholesterol in ATAK‐S laying hens.     

Effects of dietary supplementation of resveratrol on performance,egg quality,yolk cholesterol and antioxidant enzyme activity of laying hens

1. This experiment was conducted to evaluate the effects of dietary supplementation of resveratrol on laying performance, egg quality, egg yolk cholesterol and antioxidant enzyme activities of laying hens.

2. A total of 360 Beijing PINK-1 laying hens (60 weeks old) were randomly distributed among five dietary treatments, each of which included 6 replicates of 12 hens. Dietary treatments were basal diet supplemented with 0 (control), 0.5, 1.0, 2.0 and 4.0 g/kg diet resveratrol. The study lasted for 9 weeks including 1 week of adaptation and 8 weeks of the main experimental period.

3. The results indicated that dietary resveratrol significantly improved feed conversion ratios during 5–8 weeks and 1–8 weeks of the trial. Increasing dietary concentrations of the resveratrol linearly improved Haugh unit and albumen height of eggs.

4. The content of total cholesterol (TC), total triglyceride (TG), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C) in serum and cholesterol in yolk was significantly decreased by dietary resveratrol, and there were significant linear correlations between these indexes and resveratrol supplemental levels.

5. Dietary resveratrol supplementation significantly improved serum Glutathione peroxidase (GSH-Px) enzyme activity and decreased serum malondialdehyde (MDA) content in groups with 2.0 and 4.0 g/kg resveratrol as compared to the control, respectively. However, supplementation of resveratrol did not affect the activity of serum superoxide dismutase (SOD).

6. It is concluded that resveratrol supplementation has a positive effect on performance, lipid-related traits and antioxidant activity of laying hens.     

Effect of expanded cottonseed meal on laying performance,egg quality,concentrations of free gossypol in tissue,serum and egg of laying hens

Three hundred and sixty Hy‐Line Brown hens, 40 week of age, were allocated to five treatments, each of which included four replicates of 18 hens. After an expanded process of cottonseed meal (CSM), free gossypol content in CSM was decreased from 1.24 to 0.40 g/kg. The dietary treatments were corn‐soybean meal based diets including 6% CSM and 6%, 8% and 10% expanded cottonseed meal (ECSM). Hens fed 8% ECSM had higher (P < 0.05) laying rate and average egg weight than those fed 6% CSM. The albumen height and Haugh unit in the control group, 6% and 8% ECSM groups were superior (P < 0.05) to other treatments. Hens fed 6% CSM resulted in severe (P < 0.05) egg yolk discoloration. Free gossypol (FG) concentrations in yolk and albumen and tissues of the 6% CSM group were greater (P < 0.05) than those in any ECSM treatments. Hens fed 6% CSM and 10% ECSM had the highest (P < 0.05) FG concentrations in the liver compared with those in the kidney and muscle, and higher (P < 0.05) FG residues in yolk than those in albumen. In conclusion, FG in CSM can be reduced by 68% through an expanded process and ECSM can be available in laying hens at up to 10% of the total diet and an appropriate replacement of soybean meal with ECSM may improve performance in laying hens.     

日粮添加甜菜碱对夏季高温蛋鸡生产性能、蛋品质及血液理化特征的影响

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...     

The effects of phytase and xylanase supplementation on performance and egg quality in laying hens

ABSTRACT

1. The aim of this study was to evaluate the effects of phytase and xylanase and their interaction on laying hen performance, egg quality, phosphorus (P) digestibility, phytate breakdown, volatile fatty acid (VFA) production and peptide YY concentration.

2. Two hundred and forty hens were allocated to cages at 22 weeks of age based on a 3 × 2 arrangement with phytase (0, 300 or 1500 FTU/kg) and xylanase (0 or 12 000 BXU/kg) as factors.

3. Phytase increased hen-day production (P < 0.05), daily egg mass (P < 0.05) and P digestibility with increasing levels of phytase (P < 0.001). Phytase fed at 1500 FTU/kg reduced IP6 and IP5 and increased myo-inositol concentration in gizzard digesta (P < 0.05). Phytase fed at 300 FTU/kg reduced IP6 in ileal digesta (P < 0.05); however, IP6 and IP5 were further reduced and myo-inositol increased when phytase was added at 1500 FTU/kg (P < 0.05).

4. Xylanase improved feed efficiency when phytase was fed at 300 FTU/kg (P < 0.05). In the absence of phytase, xylanase reduced dry matter and Ca digestibilities (P < 0.05).

5. Neither phytase nor xylanase had an effect on peptide YY or caecal VFA concentrations.     

The effects of dietary calcium iodate on productive performance,egg quality and iodine accumulation in eggs of laying hens

The aim of this study was to examine the effects of various levels of supplemental calcium iodate (CI) on productive performance, egg quality, blood indices and iodine (I) accumulation in the eggs in commercial laying hens. A total of 240 White Leghorn layers (Hy‐line W36) were divided through a completely randomized design into six treatments with five replicates and eight hens per each at 32 weeks of age. This experiment lasted for 12 weeks. Concentrations of I in the mash diets were 0.74, 3.13, 5.57, 8.11, 10.65 and 12.94 mg I/kg of feed in treatments 1–6 respectively. The added doses of CI were included 0.0 (control), 2.5, 5.0, 7.5, 10.0 and 12.5 mg/kg of diet for treatments 1–6 respectively. There were no significant differences in productive performance among the treatments. The highest eggshell strength was observed in group fed diet containing 3.13 mg I/kg (p = .014). The highest percentage of calcium and lowest percentage of phosphorus in eggshell were observed in group fed diet containing 12.94 mg I/kg (p = .0001). Feeding hens with diet containing 12.94 mg I/kg increased serum triiodothyronine‐to‐thyroxine ratio (p = .0001). Serum alanine aminotransferase activity in hens fed diet containing 12.94 mg I/kg was significantly more than control (p = .041). Blood Serum triglycerides in hens fed diet containing 8.11 mg I/kg were significantly higher than control (p = .0001). Edible fraction of the eggs of birds fed diet containing 12.94 mg I/kg was enriched by I almost 3 times more than those fed diet containing 0.74 mg I/kg. The results suggested that egg production, egg mass, feed intake and feed conversion ratio were not significantly affected by dietary I levels. Iodine accumulation in the eggs were increased by increasing dietary I levels and the level of 10 mg/kg CI could supply I enrichment of the eggs.     

不同锰源与水平对蛋鸡产蛋后期生产性能和蛋品质的影响

试验旨在研究添加不同锰源与水平羟基蛋氨酸锰对蛋鸡产蛋后期生产性能和蛋品质的影响。对照组饲喂加含106 mg/kg硫酸锰(以锰计)的基础日粮,其余各组分别添加30、50、70 mg/kg的羟基蛋氨酸锰(以锰计)来替代基础日粮中的硫酸锰。结果表明:与对照组相比,试验第14 d,日粮中添加30 mg/kg羟基蛋氨酸锰显著提高了蛋壳厚度(P<0.05),添加50 mg/kg羟基蛋氨酸锰显著提高了蛋壳重(P<0.05);试验第28 d,日粮中添加50 mg/kg羟基蛋氨酸锰显著提高了蛋壳厚度(P<0.05),添加30 mg/kg羟基蛋氨酸锰显著改善蛋壳颜色(P<0.05);试验第42 d,蛋壳厚度与添加量呈二次曲线关系,蛋壳厚度在添加量为50 mg/kg时达到最大值(P<0.01)。与对照组相比,试验第14 d,日粮中添加30 mg/kg羟基蛋氨酸锰显著降低了鸡蛋的哈夫单位和蛋黄比例(P<0.05)。试验第42 d,与对照组相比,日粮中添加30 mg/kg羟基蛋氨酸锰显著降低了鸡蛋的蛋黄比例(P<0.05)。试验结果表明,添加50 mg/kg的羟基蛋氨酸...     

Rare earth element‐enriched yeast improved egg production and egg quality in laying hens in the late period of peak egg production

The objective of this study was to determine the effects of rare earth element‐enriched yeast (RY) on egg production, coefficient of total tract apparent digestibility (CTTAD), egg quality, excreta gas emission and excreta microbiota of laying hens. A total of 216 ISA brown laying hens of 52 weeks of age were used in a 5‐week feeding trial and data were collected every week. Birds were randomly allotted to three dietary treatments each with six replicates and 12 hens per replicate. Each cage (38 cm width × 50 cm length × 40 cm height) contained one hen. Treatments consisted of corn–soya bean meal‐based diet supplemented with 0, 500 or 1000 mg/kg of RY. From weeks 55 to 56, inclusion of RY linearly increased (p < 0.05) egg production. The CTTAD of nitrogen was increased (linear, p < 0.05) with increasing dietary level of RY. In week 55, yolk height and Haugh units were increased linearly (p < 0.05) with increasing dietary RY content. However, no significant effects were observed in terms of excreta emissions and excreta microbiota in laying hens. In conclusion, dietary supplementation with RY improved egg production and CTTAD of nitrogen and slightly improved egg quality in laying hens of the late period of peak egg production.     

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low‐crude‐protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L‐Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57–0.66%. In addition, serum‐free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low‐CP diet compared with hens fed CP (16.18%) and hens fed 0.57–0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF‐γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL‐2, IL‐6, IL‐1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low‐crude‐protein diet of laying hens during the peak production period.     

Genome‐wide association study for egg production and quality in layer chickens

Discovery of genes with large effects on economically important traits has for many years been of interest to breeders. The development of SNP panels which cover the whole genome with high density and, more importantly, that can be genotyped on large numbers of individuals at relatively low cost, has opened new opportunities for genome‐wide association studies (GWAS). The objective of this study was to find genomic regions associated with egg production and quality traits in layers using analysis methods developed for the purpose of whole genome prediction. Genotypes on over 4500 birds and phenotypes on over 13 000 hens from eight generations of a brown egg layer line were used. Birds were genotyped with a custom 42K Illumina SNP chip. Recorded traits included two egg production and 11 egg quality traits (puncture score, albumen height, yolk weight and shell colour) at early and late stages of production, as well as body weight and age at first egg. Egg weight was previously analysed by Wolc et al. ( 2012 ). The Bayesian whole genome prediction model – BayesB (Meuwissen et al. 2001 ) was used to locate 1 Mb regions that were most strongly associated with each trait. The posterior probability of a 1 Mb window contributing to genetic variation was used as the criterion for suggesting the presence of a quantitative trait locus (QTL) in that window. Depending upon the trait, from 1 to 7 significant (posterior probability >0.9) 1 Mb regions were found. The largest QTL, a region explaining 32% of genetic variance, was found on chr4 at 78 Mb for body weight but had pleiotropic effects on other traits. For the other traits, the largest effects were much smaller, explaining <7% of genetic variance, with regions on chromosomes 2, 12 and 17 explaining above 5% of genetic variance for albumen height, shell colour and egg production, respectively. In total, 45 of 1043 1 Mb windows were estimated to have a non‐zero effect with posterior probability > 0.9 for one or more traits.     

复合型抗应激添加剂对夏季蛋鸡产蛋性能、蛋品质及血清生化指标的影响

为了研究复合型抗应激添加剂对夏季蛋鸡产蛋性能、蛋品质及血清生化指标的影响,试验选用120只42周龄伊莎褐蛋鸡,随机分为2组,每组设6个重复,每个重复lO只;对照组饲喂基础日粮,试验组饲喂基础日粮＋80mg／kg复合型抗应激添加剂——禽专用添佳安肽,试验期为60d。结果表明：与对照组相比,试验组产蛋率显著提高5．56％（P〈0．05）,料蛋比显著降低4．74％（P〈0．05）,但对采食量和平均蛋重无显著影响（P〉0．05）;试验组蛋壳强度显著提高15．27％（P〈O．05）,但对蛋壳厚度、蛋白高度、哈夫单位无显著影响（P〉0．05）;试验组血清皮质醇水平显著下降53．91％（P〈0．05）,T_3、T_4水平分别显著下降20．12％、23．57％（P〈0．05）,尿素氮水平显著下降35．35％（P〈0．05）,但对血糖水平无显著影响（P〉0．05）。说明蛋鸡日粮中添加复合型抗应激添加剂——禽专用添佳安肽,具有显著抗热应激效应和增加蛋鸡采食量的作用。