日粮添加海藻粉和抗菌肽对海兰褐蛋鸡产蛋性能的影响

采用4×2（海藻粉×抗菌肽）完全随机试验设计,研究日粮添加不同水平的海藻粉（0．0％、1．0％、3．0％、5．0％）和抗菌肽（300 mg/kg、600 mg/kg）对蛋鸡不同产蛋期（24～27周龄和28～31周龄）产蛋性能的影响。结果表明：（1）日粮海藻粉的添加水平显著提高了产蛋率和料蛋比（P＜0．05）。（2）抗菌肽添加水平在28～31周龄显著提高了产蛋率（P＜0．05）。（3）海藻粉和抗菌肽互作效应显著提高了产蛋率和料蛋比（P＜0．05）。结果提示,海藻粉和抗菌肽对蛋鸡产蛋性能的影响存在互作效应,以海藻粉5％、抗菌肽300 mg/kg水平组合最为理想。     

麦麸替代玉米对蛋鸡生产性能和蛋品质的影响

本试验旨在研究用部分麦麸替代基础日粮中的玉米对蛋鸡生产性能的影响。选取24周龄的海兰褐蛋鸡600只,随机分为5组,每组6个重复,每个重复20只。对照组饲喂基础日粮,试验组分别饲喂麦麸替代基础日粮中玉米的5%,10%,15%,20%的试验日粮,预饲期7 d,正式试验期35 d。结果表明:麦麸替代玉米提高了平均日采食量、平均蛋重、产蛋率、料蛋比、蛋比重和哈夫单位(P<0.05)。试验表明,麦麸替代玉米,可以提高蛋鸡生产性能,改善蛋品质,且替代10%的玉米效果最佳。     

生态制剂对蛋鸡产蛋性能的影响

将两歧双歧杆菌、保加利亚乳杆菌和嗜热链球菌分别制成每克含活菌1亿的微囊,等量混合而成生态制剂,按0.125%添加在蛋鸡基础饲料中,饲喂蛋鸡,同时设对照组,观察蛋鸡产蛋性能的变化。经过1个月的实验,结果表明：该生态制剂对产蛋高峰期,可提高产蛋率10.08%、降低死亡率46.26%、提高饲料利用率32.16%;而对产蛋后期,提高产蛋率仅3.46%、降低死亡率58.50%、饲料利用率差异无显著性（P＞0.01）。     

益生素对祖代伊沙蛋鸡性能的影响

２５６９羽祖代伊沙蛋鸡（ＩＳＡＢｒｏｗｍ）,随机分成２组。试验组１１５３羽,在基础日粮中添加０１５％的益生素,对照组１４１５羽饲喂基础日粮,不添加益生素,试验期３０天。试验结果表明,试验组和对照组的平均产蛋率分别为７２３２±４１４％和６６７３％±６６１％,试验组较对照组高８３８％,差异极显著（Ｐ＜００１）;试验组和对照组的种蛋合格率分别为６２９１％±５９０％和５４５２％±７７８％,试验组比对照组高１５３９％,差异极显著（Ｐ＜００１）;试验组的种鸡成活率较对照组高０３９％,差异不显著;试验组和对照组的鸡舍温度分别为３５８７℃±１６７℃和３４９７℃±１７０℃,试验组较对照组高０９℃,差异显著（Ｐ＜００５）。该试验结果提示,在高温季节使用益生素,具有延缓蛋鸡产蛋率及种蛋合格率下降作用;通过分析产蛋率及种蛋合格率相关性和回归模型表明,益生素能显著地影响产蛋率和种蛋合格率的相关性,提高种蛋合格率。     

绍兴鸭血液生化指标与产蛋性状间相关的通径分析

本研究估测了125羽60日龄的绍兴鸭血液中的总蛋白（TP）、胰岛素样生长因子-I（IGF-I）的含量和谷草转氨酶（GOT）、谷丙转氨酶（GPT）的活性与3个产蛋性状（300日总蛋数、300日总蛋重、平均蛋重）的表型相关,再分别以3个产蛋性状为依变量对60日龄的性状相关进行了通径分析,为绍兴鸭的早期选育提供科学依据.相关分析结果表明:60日龄绍兴鸭血液中GPT与300日总蛋数、300日总蛋重的表型相关为中等程度相关（0.5274、0.6234）,与平均蛋重的表型相关为强相关（0.6733）,都达极显著水平（P <0.01）.TP与3个产蛋性状的表型相关为弱相关（0.2067、0.2629、0.3026）,但都达显著水平（P<0.05）.通径分析结果为:GPT对3个产蛋性状的正直接影响均较大（0.5275、0.6109、0.6395）.     

用聚合酶链反应检测产蛋下降综合症病毒核酸的研究

根据对ＥＤＳ－ＤＮＡ重组质粒ｐＴＥＺＰ３和ｐＴＥＺＰ２８的核酸序列分析结果,设计了两对引物,它们均能从ＥＤＳ－ＤＮＡ上扩增出一个特异片段,其长度分别为２３８ｂｐ和２０９ｂｐ。经比较,ＰＣＲ比血球凝集试验至少灵敏２００倍,比核酸杂交试验灵敏千万倍,对１００份自然发病鸡的肛拭子,血液和软壳蛋样品的检测结果表明;ＰＣＲ的阳性出率远高于酸杂交试验,并用病毒分离方法证实了ＰＣＲ对野外病料的检出结果是可信的。     

不同饲养方式对各产蛋阶段鸡蛋品质的影响

目的：比较不同饲养方式对鸡蛋品质的影响,为蛋鸡产业化生产提供指导。方法：以如皋黄鸡为试验素材,采用笼养和平养两种饲养方式,测定不同产蛋阶段常规蛋品质、营养成分和矿物元素含量。结果：产蛋初期,平养条件下蛋黄色泽、脂肪和胆固醇含量极显著高于笼养（P＜0-01）,铜和铁含量显著低于笼养（P＜0-05）。产蛋中期,平养条件下蛋壳强度、蛋黄重量、蛋黄比率、蛋黄蛋白比均显著低于笼养（P＜0-05）;哈氏单位以及蛋白质、维生素E和氨基酸含量均显著高于笼养（P＜0-05）;蛋黄色泽、维生素A和胆固醇含量均极显著高于笼养（P＜0-01）,锰含量极显著低于笼养（P＜0-01）。产蛋后期,平养条件下胆固醇含量极显著高于笼养（P＜0-01）;蛋白质、维生素A和铜含量显著高于笼养（P＜0-05）;锰含量极显著低于笼养（P＜0-01）;硒含量显著低于笼养（P＜0-05）。结论：不同产蛋阶段,饲养方式对鸡蛋品质均有一定的影响。     

用生物素化重组质粒探针检测产蛋下降综合症病毒核酸

用ＥＤＳ－７６标准毒株感染鸭胚后,提取病毒核酸,经ＰｓｔＩ酶切后,与质粒ｐＴ７／Ｔ３α－１９重组,并转化到大肠杆菌ＤＨ５α中,筛选出一个插入片段为３１８ｂｐ的重组质粒,并命名为ｐＴＥＺＰ３。用生物素标记该重组质粒后,分别对正常鸭胚尿囊液、各地分离的ＥＤＳ毒株和禽类易感的几种病毒进行核酸杂交试验,结果该探针对实验中收到的几种ＥＤＳ分离毒均产生阳性反应,而不与正常鸭胚尿囊液和其它几种禽类病毒交;该探针     

外源促性腺激素处理后鸡产蛋及孵化研究

目的:探讨促卵泡素(FSH)对低产期肉用种母鸡在产蛋数量和孵化的影响,寻求较佳的用于提高低产期母鸡产蛋的激素剂量。方法:本试验采用同种激素不同剂量的处理方式,比较实验组和对照组产蛋量和孵化情况。结果:注射不同剂量的激素对鸡的产蛋有一定的影响,实验组一的平均产蛋数与对照组接近,其它四组均显著低于对照组(P<0.05),孵化率与健雏率与对照组无显著差异(P>0.05)。结论:小剂量激素处理对鸡产蛋量没有太大的影响,但大剂量会引起鸡生殖系统萎缩,激素处理对受精卵孵化及雏鸡生长并无负面影响。     

蛋鸡产蛋进程的回归模型

采用回归分析方法,建立了伊莎商品代蛋鸡在产蛋过程中不同等级蛋蛋重的比率与产蛋时间的回归模型,并探讨了平均蛋重随产蛋时间的变化规律．     

Population Irruptions of Northern Bobwhite: Testing an Age-Specific Reproduction Hypothesis

Abstract: Age-specific reproduction has been suggested for northern bobwhite (Colinus virginianus) and has been hypothesized as a factor contributing to population irruptions. However, little research has been conducted on the subject. We conducted a laboratory and field study to determine if age-specific reproduction occurred in northern bobwhites. Our objectives were to compare 7 reproductive measures (% F nesting, date of first incubated nest, egg-laying rate, nesting rate, clutch size, egg mass, and egg hatchability) between first- and second-year breeders and determine if differential reproduction was impacted by diet quality. The laboratory study consisted of a 2 × 2 factorial experiment with age and diet quality (low protein [12%] and high protein [24%]) as the factors. Data for the field study represented a 6-year data set of bobwhite reproduction (May-Sep 2000-2005) obtained from an ongoing radiotelemetry study in southern Texas, USA. We documented similar productivity (i.e., % F laying, egg-laying rate, and egg mass) and timing of laying (i.e., date of first egg) between juvenile (n = 33) and adult bobwhites (n = 27) in our laboratory study. However, females on the high-protein diet exhibited a greater egg-laying rate than females on the low-protein diet. Under field conditions, we also documented no difference in productivity (% F nesting, nesting rate, clutch size, egg hatchability) and timing of nesting (date of first incubated nest) between age classes (n = 59 juv and 32 ad). Our findings do not support early suppositions of age-specific reproduction in quail. Quail irruptions should not be influenced by population age structure as it relates to age-specific reproduction.     

Egg-laying tactic in Phyllomorpha laciniata in the presence of parasitoids

Female insects are expected to choose oviposition sites that have the best conditions for offspring development and survival. Natural enemies, such as predators and parasitoids, may have a strong influence on the selection of oviposition substrates by phytophagous insects. The golden egg bug, Phyllomorpha laciniata (Villers) (Heteroptera: Coreidae) has an unusual reproductive strategy. Females mainly use conspecifics, both males and other females, as egg-laying substrates, but occasionally they oviposit on plants as well. Survival of the eggs is higher when eggs are carried by conspecifics than when they are laid on plants, due to predation and parasitism. We investigated egg-laying behavior in the forced presence of the egg parasitoid Gryon bolivari (Giard) (Hymenoptera: Scelionidae). Specifically, we studied whether females provide egg protection by avoiding oviposition under the risk of egg parasitization. We expected a lower oviposition rate under parasitoid presence, and the eggs, if any, to be placed preferably on conspecifics and not on plants, thus ensuring higher survival of the progeny. The results show that P. laciniata 's egg-laying rate was lower when they were enclosed with parasitoids than when parasitoids were absent, especially when plants were the only substrate to oviposit on. Moreover, females showed strong preference for laying eggs on conspecifics rather than on plants. Egg-laying in P. laciniata appears to be not only influenced by the availability of conspecifics, but also by the presence of egg parasitoids. This indicates that females may be able to detect G. bolivari and avoid oviposition when parasitoids are present. We discuss the possibility of conspecifics as enemy-free space.     

Feeding strategies of anthropophilic mosquitoes result in increased risk of pathogen transmission

Vector-borne disease specialists have traditionally assumed that in each egg-laying cycle mosquitoes take a single bloodmeal that is used for egg development and feed on plant sugars for flight and production of energy reserves. Here we review research showing that for two of the most important vectors of human pathogens (Anopheles gambiae and Aedes aegypti) imbibing multiple bloodmeals during a gonotrophic cycle while foregoing sugar feeding is a common behaviour, not an exception. By feeding preferentially and frequently on human blood these species increase their fitness and exponentially boost the basic reproduction rate of pathogens they transmit. Although the epidemiological outcome is similar, there are important differences in processes underlying frequent human contact by these species that merit more detailed investigation.     

Could hosts considered as low quality for egg-laying be considered as high quality for host-feeding?

When parasitoid females encounter a host, they can either lay an egg and thus invest in current reproduction or feed on the host and thus invest in future reproduction. However, hosts could have different values according to their parasitized status. Whereas already parasitized hosts represent poor quality for egg-laying, they could have a high nutritive value for feeding. Moreover, the optimal strategy adopted generally depends on the females’ physiological state. In this study, the impact of the females’ physiological state on their reproductive strategies was investigated in the solitary parasitoid Anisopteromalus calandrae. We analysed how their age and diet influenced (i) the use of hosts (feeding vs. oviposition) and (ii) host selection (previously parasitized vs. unparasitized). Our results show that both age and diet influence the reproductive strategy of A. calandrae females: old females fed with the poorer diet laid fewer eggs and made more host-feeding than others. Females also showed a preference for already parasitized hosts for feeding. This strategy cannot be explained by the nutritive value of haemolymph, as parasitized hosts carry fewer lipids. However, as parasitized hosts are also paralyzed, it could be less costly to feed on them than on unparasitized hosts.     

Effect of alfalfa meal in diets of laying quails on performance, egg quality and some serum parameters

This study was conducted to investigate the effects of increasing levels of alfalfa meal in the diet of laying quails on egg production, feed consumption, feed efficiency, egg quality, egg yolk cholesterol and selected serum parameters. In this study, 192, 10-week old quails (Coturnix coturnix japonica) were evenly distributed to four groups with four replicates of 12 quails each. The control group was fed a basal diet containing 0% alfalfa meal and the remaining groups received 3, 6 or 9% alfalfa meal for 12 weeks. Live weight, feed consumption, and egg production were recorded and feed efficiency were calculated. Eggs were examined for interior and exterior quality and egg yolk cholesterol content. At the end of the experiment, blood samples were collected and sera were analysed for serum Ca, inorganic P (P(i)), Mg, triglycerides and total cholesterol. Any level of alfalfa meal had no effect on live weight, egg production, feed consumption, feed efficiency, egg weight, and egg yolk index. Six percent and 9% alfalfa meal increased specific gravity of whole egg and eggshell thickness as well as serum P(i) levels. Nine percent alfalfa meal reduced serum triglycerides, total cholesterol levels and egg yolk cholesterol content. The results of this experiment indicated that addition of 9% alfalfa meal into the laying quail diet may improve eggshell quality and reduced serum triglycerides and serum and egg yolk cholesterol without any adverse effect on performance.     

Effect of Alfalfa Meal in diets of laying quails on performance,egg quality and some serum parameters

This study was conducted to investigate the effects of increasing levels of alfalfa meal in the diet of laying quails on egg production, feed consumption, feed efficiency, egg quality, egg yolk cholesterol and selected serum parameters. In this study, 192, 10-week old quails (Coturnix coturnix japonica) were evenly distributed to four groups with four replicates of 12 quails each. The control group was fed a basal diet containing 0% alfalfa meal and the remaining groups received 3, 6 or 9% alfalfa meal for 12 weeks. Live weight, feed consumption, and egg production were recorded and feed efficiency were calculated. Eggs were examined for interior and exterior quality and egg yolk cholesterol content. At the end of the experiment, blood samples were collected and sera were analysed for serum Ca, inorganic P (P_i), Mg, triglycerides and total cholesterol. Any level of alfalfa meal had no effect on live weight, egg production, feed consumption, feed efficiency, egg weight, and egg yolk index. Six percent and 9% alfalfa meal increased specific gravity of whole egg and eggshell thickness as well as serum P_i levels. Nine percent alfalfa meal reduced serum triglycerides, total cholesterol levels and egg yolk cholesterol content. The results of this experiment indicated that addition of 9% alfalfa meal into the laying quail diet may improve eggshell quality and reduced serum triglycerides and serum and egg yolk cholesterol without any adverse effect on performance.     

Cestrum diurnum leaf as a source of 1,25(OH)2 Vitamin D3 improves egg shell thickness

A continuing concern of the poultry industry is the high incidence (12%) of egg losses in the laying house due to poor egg shell quality. Calcium (Ca) homeostasis is a key factor in egg shell formation. The economy of Ca utilisation is under the control of Vitamin D(3), particularly its active metabolite 1,25-dihydroxy cholecalciferol [1,25(OH)(2)D(3)]. Supplementation of 1,25(OH)(2)D(3) has been shown to increase specific gravity, shell thickness and shell weight of the egg. However, commercially available synthetic 1,25(OH)(2)D(3) is very expensive. Earlier studies from our Institute [Phytochemistry 37 (1994) 677] have identified a cheap, natural and rich source of 1,25(OH)(2)D(3) in the leaves of Cestrum diurnum (CD), a member of the Solanaceae family. In this study, CD leaves were explored as a source of 1,25(OH)(2)D(3) in the feed of layer birds to improve the egg shell thickness. Fifteen-week-old white leghorn layers were divided into four treatments of 60 birds each and as follows: (I) normal diet with Vitamin D(3), (II) normal diet with Vitamin D(3) + CD, (III) normal diet without Vitamin D(3) and, (IV) normal diet without Vitamin D(3) + CD powder. CD leaf powder was incorporated in to the feed at 0.3% level. The experimental feeding was continued up to 72 weeks of age of the birds. Weekly food intake and daily egg production were noted throughout the experimental period and the specific gravity of the eggs, feed consumed to lay one egg and egg shell thickness were determined. Incorporation of CD leaves in the feed had the maximal effect on all the parameters studied. The feed consumed to lay one egg was 20 g less than the control group. The specific gravity of the egg was higher by 0.005, than the control egg, indicating a 5% decrease in the breakage of eggs in CD fed chicks. Also there was a significant increase (P < 0.001) in egg shell thickness. The data suggest that incorporation of CD leaf powder in the feed of poultry layers increased the egg shell thickness, which in turn could decrease the economic loss due to breakage of eggs.     

Palm kernel meal as a feed for poultry. 4. Use of palm kernel meal by laying birds

In each of 2 experiments, 200 laying birds of the Harco strain were used to determine the effects of increasing amounts of dietary palm kernel meal (PKM) on egg production rate and egg quality. The results show that up to 40% of PKM can be included in diets for layers without any adverse effects on performance or egg quality. As the proportion of PKM increased beyond 40%, there was a significant drop in egg production (P < 0.05), egg weight (P < 0.01), feed intake (P < 0.01) and feed conversion efficiency (P < 0.01). The cost of feed required to produce 1 kg of eggs was reduced by feeding with PKM. Diets containing 50–70% of PKM caused the production of very watery faeces. It is recommended that the maximum level of inclusion of PKM in the diet of laying birds should be 40%.     

Potential of alfalfa as an alternative molt induction diet for laying hens: egg quality and consumer acceptability

Dietary molt induction to initiate additional egg laying cycles in commercial laying hen flocks is a wide spread practice in the United States. Feed deprivation is the most commonly used method but this practice has generated several concerns which has lead to research for viable alternative approaches. From a management standpoint a single ingredient molting diet consisting of high fiber-low energy represents an easily adaptable diet for large laying hen production units. Alfalfa meal is readily available in most commercial locations and possesses many of the desirable properties of an ideal laying hen molt diet. In the current study hens at a commercial laying facility were molted by both alfalfa and feed deprivation. After the hens had reentered post-molt commercial egg production, eggs were examined for egg quality performance. Egg shell strength, albumen height, yolk height, weight, length, and yolk color were all tested using various mechanical techniques. The eggs were also sampled for testing by consumer sensory panels that assessed the desirability of the eggs' color and flavor/texture. Eggs laid by hens molted by alfalfa had a significantly lower (p<0.05) "a*" level of colorimetry. Eggs laid by hens molted with alfalfa also exhibited significantly higher (p<0.05) egg weights and length. In the consumer sensory test, there was no significant difference (p>0.05) in color or flavor/texture scores in eggs from either feed deprived or alfalfa molted hens. The consumer sensory and mechanical quality attributes indicates that alfalfa shows promise as an alternative molt induction diet by providing a single diet option for extending egg production into a second egg laying cycle.     

Is sequential feeding of whole wheat more efficient than ground wheat in laying hens?

The impact of sequential feeding of whole or ground wheat on the performance of layer hen was investigated using ISABROWN hens from 19 to 42 weeks of age. In addition, the effect of reduced dietary energy content of a complete diet was also investigated. Four treatments were tested. Whole wheat was alternated with a protein-mineral concentrate (balancer diet) in a treatment (sequential whole wheat: SWW), while another treatment alternated ground wheat (sequential ground wheat: SGW) with the same balancer diet. The control (C) was fed a complete layer diet conventionally. Another treatment (low energy: LE) was fed a complete diet conventionally. The diet contained lower energy (10.7 v. 11.6 MJ/kg) compared to the C. Each treatment was allocated 16 cages and each cage contained five birds. Light was provided 16 h daily (0400 to 2000 h). Feed offered was controlled (121 g/bird per day) and distributed twice (2 × 60.5 g) at 4 and 11 h after lights on. In the sequential treatment, only wheat (whole or ground) was fed during the first distribution and the balancer diet during the second distribution. Left over feed was always removed before the next distribution. The total feed intake was not different between SWW and SGW, but the two were lower than C (P < 0.05). Wheat intake was however, lowered with SGW compared to SWW (P < 0.05). Egg production and egg mass (EM) were not different between treatments. Egg weight was lower with SGW than with SWW (P < 0.05), but the two were similar to C. Body weight (BW) was lowered (P < 0.01) with SGW relative to SWW and C, SWW BW being also lower than the C one. The efficiency of egg production was increased (P < 0.01) with the SWW and SGW relative to the control. Birds fed LE had higher feed intake (P < 0.05) but they had similar egg production and EM compared to the two sequential treatments. The efficiency of feed utilization was also reduced (P < 0.01) with LE compared to SWW and SGW. It was concluded that sequential feeding is more efficient than conventional feeding. In addition, whole wheat appeared more efficient than ground wheat in terms of egg and BW.