蛋鸡对环境因子的生理反应机制研究进展

蛋鸡生长发育和生产过程受各种环境因子的影响,如温度、氨气、光照和二氧化碳等,其中温度和氨气是鸡舍冷热环境和空气质量环境控制中最为重要的两个方面,明确蛋鸡对重要环境因子的生理反应机制对鸡舍环境控制意义重大.文章综述了鸡舍内主要环境因子对蛋鸡影响机制的研究进展,尤其是温度和氨气对蛋鸡生产性能和生理影响的研究现状,总结了目前...     

Amino acid nutrition in egg production industry

The egg production industry is facing various problems that need to be solved. For amino acid nutrition to achieve scientific and economical feeding of laying hens, it is necessary to elucidate the content, digestibility, or availability of nutrients of feedstuffs and feeds and the requirement of amino acids for laying hens. In addition, improvement to quality of eggs and meat of spent hens, methods of management and development of new feedstuffs are essential. For sustainable animal production, decrease in excreta and animal welfare should be studied. The real‐time determination of content and digestibility of amino acids in feedstuffs are essential for formation of feeds. Recent advances in the near infrared reflectance analysis will be able to determine the content, digestibility and availability of nutrients in feedstuffs and feeds, if we have a supplemental amount of conventional analysis to define the calibration population. The amino acid requirements are affected by various factors. Therefore the method to quickly and exactly determine amino acid requirements in response to various factors is necessary. By using plasma free amino acid concentration as a criterion, it is possible to determine amino acid requirements in various conditions of laying hens within a short experimental period, repeatedly using the same animals. Because the amino acid requirements differ among individual animals, it should be expressed as grams per hen per day. Practically, it is impossible to formulate various feeds for individual hens. The various expressions have been developed and these expressions have advantages and disadvantages. The nitrogen excretion of laying hens is easily reduced by reducing dietary nitrogen levels and restricting the feed intake. The availability of amino acid may be improved by feeding management, and supplementing enzyme, but the quality of eggs and meat of spent hens and welfare of laying hens are not affected by amino acid nutrition.     

Importance of the rearing period for laying hens in alternative systems

Feather pecking and cannibalism are still major problems in alternative systems for laying hens. Literature and practical experience indicate that unfavourable rearing conditions might be important risk factors for the occurrence of these behavioural disturbances during the laying period.Typical rearing conditions of laying hens from 50 rearing units in Germany and Austria are presented. Obvious risk factors during rearing for feather pecking and cannibalism during the laying period were found. Most flocks were kept under high stocking density (mean: 15 pullets per m' useable area) and some flocks had access to litter only after the second week of life or access to raised perches after the fourth week of life. Plumage condition of pullets and laying hens varied widely in non-beak-trimmed as well as in beak-trimmed flocks.The percentage of pullets with damaged plumage was higher in beak-trimmed than in non-beak-trimmed flocks (medians: 53 % versus 30 %, p = 0,022). In laying hens there was a higher percentage of hens with plumage damage in non-beak-trimmed flocks compared to beak-trimmed flocks (medians: 23 % versus 50 %, p = 0,007). Data analysis will be continued, especially with regard to particular risk factors.     

蛋鸡兽用抗菌药使用减量化养殖现状与研究对策

不合理使用抗菌药严重威胁到蛋鸡养殖健康,引起鸡蛋中药物残留和细菌耐药性产生风险,影响鸡蛋食品安全和公共卫生安全。本文基于我国自2018年起开展的涵盖蛋鸡养殖的兽用抗菌药使用减量化行动,从蛋鸡养殖的减量化现状、问题、对策等方面进行综述,以期为推动蛋鸡兽用抗菌药使用减量化养殖提供参考。     

Behaviour of laying hens in aviaries--review. Part 1: Social and resting behaviour of hens

This literature review gives information about important behaviour categories of laying hens kept in aviary systems. Based on current knowledge, the differences in behaviour of hens in aviaries compared to the behaviour of hens living under "close to natural" conditions are assessed quantitatively and qualitatively. The focus of this first review is put on resting and particularly on social behaviour. So far "optimal" group size for laying hens and consequences of oversized groups for the well-being of laying hens are unknown, thus, rendering further research necessary. Referring to the resting and social behaviour of laying hens, proposals for the design of the housing system aviary are given. A second part will deal with feeding, reproductive and dustbathing behaviour.     

湖北省蛋鸡养殖用药现状、存在问题与建议

为了解湖北省蛋鸡养殖情况,更好地响应和推广兽药减量化行动,对湖北省9个地市内的蛋鸡养殖场基本信息和用药情况进行调研。结果表明：近几年本省蛋鸡养殖场在饲养管理和药物使用方面有一定进步,同时也存在缺乏科学的疫病防治体系、药物使用存在风险隐患等不足,会导致产品质量安全问题。本文分析了产生原因,并提出相关建议,以促进湖北省蛋鸡养殖的科学健康发展,提升本省畜禽产品质量安全水平.     

A pecking device as an environmental enrichment for caged laying hens

To improve the welfare of caged laying hens, a pecking device made of stones was introduced on the cage floor. Twenty‐four White Leghorn hens aged 15 months were divided into four groups: single‐housed hens with device, single‐housed control hens, pair‐housed hens with device and pair‐housed control hens. Hens housed with the device pecked at various pecking objects less often than control hens. Agonistic behavior was also lower in hens with the device than in hens without the device, implied a possibility of improvement in quality of pecking stimuli with the device. Not only time spent pecking, but also quality of pecking might be important to fill their need for stimulation. Both single‐ and pair‐housed hens more often pecked at the device in the evening. Response to various pecking objects also showed that pecking behaviors were most frequently expressed in the evening. Increased foraging at dusk is a well‐known habit; therefore, the increase in pecking behavior in the evening might reflect the hens' general circadian rhythm. These results indicate that the device made of stones could promote some instinctive behavior. Enhancement of behavioral repertories and reduced agonistic behavior with the pecking device might improve the welfare of caged laying hens.     

Haematology of the Japanese quail (Coturnix coturnix japonica)

Blood samples from 30 2‐week‐old unsexed chicks, 25 adult males, 30 non‐laying hens and 19 laying hens were examined to characterise haematological norms in Japanese quail (Coturnix coturnix japonica) under various physiological conditions such as age, sex and laying. Young quail had significantly lower erythrocyte counts, packed cell volumes, haemoglobin content, mean corpuscular haemoglobin concentrations, numbers of thrombocyte::, percentages of lymphocytes and plasma protein levels than did the adult males and the non‐laying hens. The total leucocyte count of the young birds was not significantly different from that of the males and just different from that of the non‐laying hens. The young birds also showed a higher mean corpuscular volume, mean corpuscular haemoglobin and percentages of heterophils and monocytes in comparison with the adult males and the non‐laying hens. A comparison between males and females showed that males had a higher erythrocyte count, packed cell volume and haemoglobin content and a lower concentration of plasma proteins than the adult females. Excepting for an elevated relative count of eosinophils, no influence attributable to laying was observed.     

雌激素-雌激素受体通路影响母鸡脂肪肝发生的可能机制

肝脏是鸡进行脂质代谢的重要场所,脂肪肝综合征是产蛋期母鸡常见的一种亚临床生理性代谢综合征,脂肪肝综合征呈渐进性发展,特别是进入产蛋后期会严重影响母鸡的健康和生产性能,给养殖业带来经济损失.雌激素水平与母鸡产蛋和肝脏脂肪代谢功能密切相关,雌激素的作用主要由雌激素受体(ER)介导.大量的数据表明,ERα和ERβ在哺乳动物的...     

Bitter vetch as a single dietary ingredient for molt induction in laying hens

Molting is used to increase productivity in the second laying cycle of commercial laying flocks. We report here the applicability of whole grain of bitter vetch as an alternative method for molt induction in laying hens. A total of 120 laying hens were molted by feed withdrawal (FW), a high-Zn diet (HZn), a moderate-Zn and Ca-P-deficient diet (MZn-CaP), or whole grain of bitter vetch (BV). Egg production ceased first in FW-treated hens and last in MZn-CaP-treated hens (P < 0.05). The rest period was longer (P < 0.05) in hens exposed to the BV diet, which proved to be comparable with the FW treatment for postmolt egg production. Egg mass for 4 to 16 wk after the molting was greater (P < 0.05) for hens molted by BV than hens molted by the MZn-CaP diet. Egg weight and yolk color were not (P > 0.05) significantly different among various molting induction methods. Albumen height and Haugh unit of eggs from hens molted by BV, for the most part of the experimental period, were significantly (P < 0.05) greater than for birds on the MZn-CaP diet and unmolted hens. In conclusion, use of BV grain as a single dietary ingredient proved to be effective in molt induction and improving postmolt egg production and internal egg quality when compared with unmolted hens.     

日粮添加酵母硒对蛋鸡血清生化指标的影响

本试验在蛋鸡日粮中添加不同浓度的酵母硒,测定蛋鸡血清生化指标,旨在探究酵母硒对蛋鸡肝脏功能的影响。结果表明:日粮添加酵母硒对蛋鸡血清谷草转氨酶(Aspartate aminotransferase,AST)、谷丙转氨酶(Alanine aminotransferase,ALT)、总胆红素(Total bilirubin,TBIL)无显著影响;日粮添加酵母硒显著降低了血清总胆固醇(Total cholesterol,TC)含量,其中0.80 mg/kg的酵母硒效果最好,第28天比对照组下降了38.06%。认为日粮添加酵母硒没有对蛋鸡肝脏功能产生不良影响,且有保护心血管的作用。     

产蛋后期蛋鸡生理特点与营养调控

蛋鸡生产周期可分为产蛋前期、产蛋高峰和产蛋后期三个阶段,产蛋后期约占整个产蛋期的一半.蛋鸡进入产蛋后期会伴随一系列的生理健康问题,如脂质代谢失调、氧化性损伤、免疫性能降低和钙磷吸收代谢紊乱等.产蛋后期蛋鸡生理状况的改变导致生产性能降低、鸡蛋品质变差.在当前饲料"全面禁抗"的大背景下,如何利用营养调控的手段来改善产蛋后期...     

Effects of Observed Incubation Behavior on Egg Production in Laying Hens of a Commercial Chicken Breed and Detection of Single-Nucleotide Polymorphisms Associated with the Incubation Behavior

Upon contact with laid eggs, avians initiate incubation behavior and stop laying additional eggs. This phenomenon suggests that the productivity of laying hens in free-range facilities may decrease because of frequent contact with laid eggs. Here, we examined whether hens of a commercial breed exhibit incubation behavior in a free-range facility and whether egg productivity subsequently decreases. One-hour observations were performed twice weekly for 3 weeks, during which 9 of 129 hens (7.0%) exhibited incubation behavior (i.e., sitting on eggs) in the free-range facility and were defined as incubating hens. During 4 d of continuous behavioral observation, incubating and non-incubating hens laid the same number of eggs statistically (4.6 and 3.6, on average, respectively); however, incubating hens spent significantly more time on average incubating the eggs (2071.9 min) than did the non-incubating hens (20.9 min; P<0.05), indicating a clear behavioral difference. Subsequently, the incubation behavior and egg productivity of incubating hens and a Silkie Fowl breed hen, which is known to exhibit typical incubation behavior and cessation of laying, were continuously compared for 27 d. The average minutes spent incubating eggs during the observation period increased in both the incubating hens and Silkie Fowl hen and the total time was almost the same (18,088.5 and 23,092 min, respectively). However, the Silkie Fowl hen stopped laying on day 17 after laying 17 eggs, whereas the incubating hens continued laying throughout the observation period. Incubating hens laid an average of 24.5 eggs, indicating that some hens (at least those of the commercial breed used in our study) can continue laying while exhibiting incubation behavior. A single-nucleotide polymorphism associated with incubation behavior was detected on chromosome 4 through genome-wide association analysis.     

Diurnal and oviposition-related changes in heart rate, body temperature and locomotor activity of laying hens

Diurnal and oviposition patterns of heart rate (HR), deep body temperature (BT) and locomotor activity (LA) in conscious and unrestrained Rhode Island Red hens were studied by a radiotelemetry system. Behavioral observations were also made on diurnal changes and during the pre‐ and post‐laying period. Heart rate, BT and LA showed characteristic diurnal changes synchronized with a photoperiod of 15 h light and 9 h dark. In the light period, HR, BT, and LA levels were significantly higher than in the dark period (P < 0.001). Furthermore, the highest levels of these parameters were recorded just after they were fed (08.30 hours), while the lowest level was measured after lights‐off and remained stable throughout the dark period. Behavioral observations indicated that during the light period the hens spent most of their time in very active movement, exhibiting various behavioral patterns. However, in the dark period the hens spent almost all their time resting. The present results suggest that performing various behavioral activities cause heat generated by muscle exertion, which plays a significant role in daily HR, BT, and LA in laying hens. However, during the 60 min before and after oviposition, LA appeared to have increased steadily toward the moment of laying, and then regressed gradually in the post‐laying period to a level significantly lower than in the pre‐laying period (P < 0.001). Furthermore, the pre‐laying behavior of hens indicated extreme restlessness and more activity, whereas the post‐laying period is characterized by less activity and increased relaxation. Consequently, laying behavior has a profound but transitory effect on HR and BT, suggesting that oviposition was probably associated with intense LA.     

吡啶甲酸铬对产蛋鸡的生物安全性评价

本试验旨在研究饲粮添加不同水平吡啶甲酸铬对北京红商品产蛋鸡产蛋性能、血液生理生化指标、器官发育和主要脏器组织病理学变化的影响,进而评价吡啶甲酸铬对产蛋鸡的生物安全性。试验采用单因子完全随机设计,选用360只23周龄北京红商品产蛋鸡,按产蛋率和体重一致的原则随机分为4个组,每个组6个重复,每个重复15只鸡。各组分别在玉米-豆粕型基础饲粮中添加0、0.6、4.0和6.0 mg/kg(以铬计)的吡啶甲酸铬。预试期21 d,正试期70 d。结果表明:1)饲粮铬添加水平对试验全期产蛋鸡产蛋性能和器官指数无显著影响(P0.05)。2)饲粮铬添加水平除显著提高试验第35天产蛋鸡血浆谷草转氨酶活性(P0.05)外,对其他血浆生化指标和血液常规生理指标均无显著影响(P0.05)。3)饲粮铬添加水平对产蛋鸡主要内脏器官的发育均无明显影响,同时均未观测到产蛋鸡的心脏、肝脏、肾脏、卵巢和输卵管组织出现明显的病理学变化。以上结果表明,产蛋鸡玉米-豆粕型饲粮中吡啶甲酸铬的推荐添加水平为0.6 mg/kg时,具有10倍的安全系数,即饲粮中以吡啶甲酸铬形式添加6.0 mg/kg铬对产蛋鸡是安全的。     

Studies on some feed additives and materials giving partial protection against the suppressive effect of ochratoxin A on egg production of laying hens

The protective effects of various feed supplements against the harmful effect of ochratoxin A on egg production and sexual maturation of two-weeks old Plymouth Rock female chicks designed for laying hens were studied. A significant protective effect of the feed additives or materials: water extract of artichoke (WEA), sesame seed (SS), Roxazyme-G (RG) and l-β phenylalanine (PHE) against the suppressive effect of ochratoxin A (OTA) on egg production of laying hens was found. A similar protection was also seen on the toxic effect of OTA on various internal organs of the same hens. A significant protection was found against the decrease of the weight or the quantity of eggs as well as against the delay of the beginning of the laying period of chicks, both of which were provoked by ochratoxin A. These protective effects were strongest in chicks treated with SS or WEA, but were slightest in chicks treated with l-β PHE.     

Enriched cage systems for laying hens--legal minimum conditions and starting points for their scientific evaluation

Recent developments in the European and national legislation regarding minimum standards for the keeping of laying hens will be causing changed conditions for egg production in the medium term. Enriched cages shall allow hens to better fulfill their needs than traditional battery cages. More space for the stretching of wings and legs, perches for resting, littered areas for scratching, pecking and dustbathing and nests for egg-laying behaviour shall allow layers to perform more of their normal behaviour patterns. However, regarding the sustainability of these systems there are different views and still a great lack of scientific data and practical experience. An overview is given on the development of European and national animal welfare legislation concerning laying hens, minimum requirements for enriched cages and the available evidence about animal behaviour, performance and health in these systems. Furthermore, a current project at the School of Veterinary Medicine Hannover on the animal welfare assessment of enriched cages, specifically on the Aviplus cage system, which was one of the first systems on the market and is in accordance with EU-directive, is introduced.     

Behavioural differences between laying hen populations selected for high and low efficiency of food utilisation

1. The effects on behaviour of selecting light-hybrid laying hens for high and low efficiency of food utilisation were investigated. Efficiency of food utilisation was measured as the proportional deviation of observed food consumption from expected food consumption. 2. Videograms of the day-time behaviour of 48 to 53-week-old individually caged hens from the F3 generation were analysed by instantaneous sampling. 3. Low-efficiency hens spent more time food-pecking, walking, pacing, and showing escape and aggressive behaviour than did high-efficiency hens. High-efficiency hens spent more than twice as much time resting and sleeping, and were never observed pacing prior to laying. 4. These differences were larger during the 2 h before laying than at other times of day. 5. Low-efficiency hens had poorer plumage, especially on the neck and the breast, and the poorer the plumage the more agitation they showed. 6. Time spent food-pecking was negatively correlated with laying frequency. 7. Differences in the occurrence of specific behaviour patterns, particularly those symptomatic of pre-laying frustration, partly explained differences in efficiency of food utilisation. Selection for higher efficiency of food utilisation might eliminate hens which are most frustrated prior to laying in cages.     

Comparison of the coagulation profile of fatty liver haemorrhagic syndrome-susceptible laying hens and normal laying hens

1. The rate of thrombin generation in plasma from Fatty Liver Haemorrhagic Syndrome-susceptible laying hens (FLHS, UCD-003) is more rapid than in plasma from age-matched normal Single Comb White Leghorn (SCWL) laying hens. 2. The rate of thrombin generation in plasma was determined by measuring the biological activity of the specific coagulation proteins, Factors V, VII, VIII, IX and X. 3. The higher activity of Factors V, VII and X in FLHS-susceptible laying hens compared with normal SCWL hens remained consistent after plasma lipid concentrations were reduced. 4. Analysis of the fatty acid composition of plasma phospholipids showed that in normal SCWL laying hens phosphatidylethanolamine contained C18:3n3 whereas it contained C20:3n3 in FLHS-susceptible laying hens. 5. The results suggest that alterations in the composition of the phospholipids that are essential cofactors in the biochemical reactions involved in thrombin generation may be a contributing factor in the development of FLHS.     

Nonwithdrawal Molting Programs

In the commercial egg industry the management practice of using feed withdrawal to induce a flock to molt has been under extreme scrutiny. This is because animal rights groups have voiced their concern about using this practice. Thus, about 5 yr ago, the United Egg Producers (UEP) commissioned 5 universities to conduct experiments to develop alternative molting programs that used nonwithdrawal feeding programs to molt laying hens. The studies conducted to date used techniques ranging from feeding hens without added salt in the diet to using readily available, low-cost feed ingredients to develop molt diets that are low in energy level and protein content. The results of these studies indicated that molting laying hens without feed withdrawal could be done successfully. Research at the University of Illinois found that feeding laying hens diets consisting of wheat middlings, soybean hulls, and corn (low protein and low energy) were successful in providing for acceptable postmolt egg production performance and economic benefit compared with using a standard feed withdrawal method. Therefore, after 5 yr of experimenting with nonwithdrawal molting methods done in several university settings, the egg industry has successfully adopted these methods of molting laying hens. In addition, based on the finding of these experiments, the UEP has revised their recommended molting guidelines to state that only nonwithdrawal molting methods will be permitted after January 1, 2006. Thus, these guidelines will apply to approximately 82% of the US egg industry.