The humoral immune response and the productivity of laying hens kept on the ground or in cages

The effects of two different keeping systems on the humoral immune response and productivity were compared for 80 laying hens, divided into four groups. Two groups each of 20 hens were kept on the ground and two were kept in cages. All the birds were immunised subcutaneously with human serum immunoglobulin G (IgG) at a dose of 100(microg per injection. The immunisations were performed twice at 4-week intervals. The lipopeptide Pam(3)Cys-Ser-(Lys)(4) was used as an adjuvant at a dose of 0.25mg per injection in one group from each housing system. In the second group from each housing system, the hens were immunised without any adjuvant (antigen control groups). The mean egg yield was significantly higher in both the antigen control group and the adjuvant group, when laying hens were kept in cages. Total egg weight remained constant in both of the housing systems. Keeping hens in cages resulted in higher mean specific antibody titres and mean immunoglobulin Y concentrations in the egg yolk.     

Welfare, health, and hygiene of laying hens housed in furnished cages and in alternative housing systems

The aim of this review was to compare welfare, health, and hygienic status of laying hens housed in furnished cages and in alternative systems. In alternative systems (floor housing and aviaries), birds have more freedom of movement and a more complex environment than in furnished cages. However, housing birds in much larger flocks in alternative systems leads to an increased risk of feather-pecking. Furthermore, air quality can be poorer in alternative systems than in furnished cages. This can affect health and hygienic status. There are only limited data on a direct comparison between furnished cages and alternative systems. Therefore, there is a need for an on-farm comparison of welfare, health, and hygienic status in these systems.     

Feeding value of sunflower- and groundnut-cakes for laying hens

Expeller-pressed, sunflower-cake samples, with and without hulls, had metabolisable energy contents of 12.74 ± 0.71 and 16.24 ± 0.84 MJ/kg, respectively, in diets of single comb, White Leghorn layers. Over a 40-week period, layer diets based on sunflower cake alone or a mixture (50:50, on nitrogen basis) of sunflower- and groundnut-cakes gave higher egg production, feed intake, feed efficiency and egg weight than diets based on groundnut cake alone. These differences were more marked at 12% than at 16 or 14% dietary protein levels. Effects of oil cakes on albumen height or yolk colour were not significant. Fertility and hatchability of eggs were similar on groundnut- and sunflower-cake diets.     

The preferences of laying hens for different concentrations of atmospheric ammonia

Ammonia gas is one of the most abundant aerial pollutants of modern poultry buildings. The current chronic exposure limit for ammonia of 25 ppm is set for human safety rather than animal welfare. This study assessed the behavioural preferences of laying hens (Gallus gallus domesticus) for different concentrations of ammonia found in commercial poultry houses. Six groups, each of six laying hens, were given the choice of three concentrations of ammonia ( approximately 0, 25 and 45 ppm) in a preference chamber over a period of 6 days and their location and behaviour recorded every 15 min. Hens foraged (p=0.018), preened (p=0.009) and rested (p=0.029) significantly more in fresh air than in the ammonia-polluted environments. There was a significant difference between the responses in 0 and 25 ppm (p<0.05) but not between 25 and 45 ppm (p>0.05). This suggests that ammonia may be aversive to hens with a threshold for this aversion between 0 and 25 ppm. Future studies should explore graded concentrations of ammonia between 0 and 25 ppm in order to suggest a new chronic exposure limit on the basis of animal welfare.     

Selection method and early-life history affect behavioural development, feather pecking and cannibalism in laying hens: A review

The aim of this review is to discuss the effects of selection method and early-life history on the behavioural development of laying hens. Especially in larger groups, laying hens often develop damaging behaviours, such as feather pecking and cannibalism, leading to impaired animal welfare. We hypothesise that the propensity to develop feather pecking and cannibalism is affected by a bird's genetic background and by its early-life history. The genetic background can be influenced by genetic selection. Laying hens are traditionally selected on individual performance, which may lead to co-selection of feather pecking and cannibalism. For hens kept in small groups, it has recently been demonstrated that a novel group selection method, focusing on group performance, can help to reduce cannibalism. However, the biological background behind the success of group selection is unknown. It is also not known whether these results from small groups can be translated to larger groups of laying hens. Regarding early-life history, laying, brooding and rearing conditions have been shown to have major effects on behavioural development and on feather pecking and cannibalism. The presence of a hen during rearing has been shown to improve foraging- and social behaviour, to decrease feather pecking and to decrease fearfulness in chicks. Applying group selection and rearing laying hens in a more natural environment may be key factors in solving the problems caused by feather pecking and cannibalism, especially if the promising results of group selection from small groups in experimental settings can be translated to large-group housing systems.     

Zearalenone, deoxynivalenol and fumonisins in mixed-feed for laying hens

Fusarium toxins are secondary metabolites produced byfungi of these genera in many commodities under certain conditions. A study was carried out to investigate the co-occurrence of zearalenone (ZEN), deoxynivalenol (DON) and fumonisins (FB₁ and FB₂) in 52 samples of mixed-feed for poultry contaminated withFusarium verticillioides. The zearalenone and deoxynivalenol were checked using immunoaffinity column and the extraction of fumonisin was performed by strong anion exchange (SAX) solid phase column. Detection and quantification were determined by high performance liquid chromatography (HPLC). The limit of detection was 5 μg/kg for ZEN, 100 μg/kg for DON and 50 and 100 μg/kg for FB₁ and FB₂ respectively.Fusarium toxins were detected in 20 samples. Sixteen samples were positive for ZEN (30.7%) presenting levels that ranged from 7.4 μg/kg to 61.4 μg/kg (mean=27.0 μg/kg). 13.5% of the samples presented contaminations of DON, with levels ranging from 100.0 μg/kg to 253 μg/kg (mean=l18.07 μg/kg). FB₁ was detected in 19.2% of samples, with levels ranging from 50.0 μg/kg to 110.0 μg/kg (mean=73.6 μg/kg). FB2 was not detected in any sample. In positive samples simultaneously contamination with two or three mycotoxins were detected in 9 of them (17.3%).     

Epidemiology and control prospects of foodborne parasitic zoonoses in the European Union

In the 27 Member States of the European Union, zoonotic parasites transmitted by food are circulating with different prevalence according to the country, the environmental conditions, the human behaviour, and the socio-economic level. Foodborne parasites can be divided in two main groups according to the way of transmission to humans. These foodborne parasites reach the human beings through the consumption of raw infected food such as muscle tissues of different animal species (Toxoplasma gondii, Sarcocystis hominis, Sarcocystis suishominis, Diphyllobotrium latum, Taenia solium, Taenia saginata, Opisthorchis felineus, Anisakis spp., Pseudoterranova spp., Trichinella spp.), or vegetables (Fasciola hepatica), and contaminated food and water resources (Giardia duodenalis, Cryptosporidium spp., T. gondii, Echinococcus granulosus sensu latu, Echinococcus multilocularis, T. solium, Taenia multiceps). As a general role, the control strategies should be based on the education of the consumers, farmers and shepherds, the improvement of farming conditions, the improvement or the development of more sensitive methods to detect these parasites in slaughtered animals and in foodstuff, a control of sewage sludge on pastures and of drinking water resources, and the reduction of contacts between livestock and wild animals which frequently represent the most important reservoir of these pathogens.     

The relationship between the comb and social behaviour in laying hens

The question of whether attributes of the combs of laying hens have any consistent relationship with dominance behaviour has yet to be answered unequivocally. This study sought to address this by investigating whether a relationship existed between the competitive ability of hens within stable groups and the size or colour of their combs. Pullets (n = 120, Hy-line^® Variety Brown) were allocated randomly to eight groups of 15 hens for 32 weeks. Over this period the length and height of each hen's comb was measured regularly to estimate the total comb area and hens were weighed. In weeks 3-10 the aggressive interactions between hens in each group were observed to calculate a behavioural dominance score (David's score) for each hen. This score was based on the outcome of agonistic interactions with other group members; and accounts for the relative strengths of all opponents. Thus dominance scores reflected the competitive ability of hens from their overall within-group fighting success. The luminance, purity and dominant wavelength of the colour of each hen's comb was measured in week 27 using a telespectroradiometer. Hens with higher dominance scores had larger combs than those with lower dominance scores (gradient of slope = 0.008 ± 0.002, P < 0.001); this relationship was consistent across the experiment. There was no association between body weight and dominance score but there was a significant inverse relationship between dominance score and the dominant wavelength of the comb (gradient of slope = −0.067 ± 0.023, P < 0.01). This indicated that hens with combs perceived by humans as more yellow-red than pure red were generally more successful competitors. Further research is required to ascertain whether or not hens utilise this information on comb size and the underexplored area of comb colour to assess the competitive ability of their opponents.     

The European Union and Migrant Labour

The European Union and Migrant Labour. Gareth Dale and Mike Cole. eds. New York: NYU Press, 1999. 256 pp.     

BIOCOMPUTATION: Some history and prospects

At first glance, biology and computer science are diametrically opposed sciences. Biology deals with carbon based life forms shaped by evolution and natural selection. Computer Science deals with electronic machines designed by engineers and guided by mathematical algorithms. In this brief paper, we review biologically inspired computing. We discuss several models of computation which have arisen from various biological studies. We show what these have in common, and conjecture how biology can still suggest answers and models for the next generation of computing problems. We discuss computation and argue that these biologically inspired models do not extend the theoretical limits on computation. We suggest that, in practice, biological models may give more succinct representations of various problems, and we mention a few cases in which biological models have proved useful. We also discuss the reciprocal impact of computer science on biology and cite a few significant contributions to biological science.     

A survey on the occurrence of ochratoxin A in feeds for swine and laying hens

Results of a 2-year (2009–2010) survey on the occurrence of ochratoxin A (OTA) in swine feed and in feed for laying hens in Portugal are reported. A total of 664 samples (478 swine feed, 186 feed for laying hens) were analyzed by a HPLC method using fluorescence detection with 2 μg kg^?1 as detection limit. In swine feed, 31 samples (6.49%) were positive for OTA. In feed for laying hens, 12 samples (6.45%) were OTA-positive. The average levels of contamination were low, with median values of positive samples at 3–4 μg kg^?1 in both years and both commodities, although a few samples contained exceptionally high levels (maximum 130 μg kg^?1). Only the maximum level sample (swine feed) contained OTA at a concentration exceeding the European Commission guidance value. The remaining OTA concentrations found in feed samples were much lower than the guidance values.     

The effects of demonstrator social status and prior foraging success on social learning in laying hens

Opportunities for social learning within a group of animals are likely to be influenced by the social dynamics of that group. Some individuals may be more influential demonstrators than others even when there are no differences in their skill level or performance. In this study of domestic hens, Gallus gallus domesticus, differences in demonstrator salience were examined. From 24 separate flocks we selected as demonstrators a dominant cockerel, a dominant hen, a mid-ranking hen or a subordinate hen. Demonstrators were pretrained to perform an operant discrimination task to obtain food. Six observers from each flock individually watched the demonstrator perform the task for four 5-min sessions held on consecutive days. On the fifth day observers were tested individually in the operant chamber. We analysed data from 19 flocks, where there were no quantitative differences in demonstrator performance. Observer hens of relatively high social status performed more correct operant pecks than observer hens of relatively low social status. Demonstrator category also had a significant effect on subsequent observer behaviour. Hens that had observed cockerels performed very few general pecks or operant pecks. Hens that had observed dominant hens performed more operant pecks, but hens that had observed sub-ordinate hens performed more general pecks in the chamber. The results suggested either that there was an interaction between dominance and gender in demonstrator salience or that dominant hens might have been influential because of some factor imperfectly associated with their dominance status. A possible candidate was the foraging ability of the dominant hens. In a second experiment using the same protocol, we manipulated the prior foraging success of dominant hens from four additional flocks but this had no significant effect on their subsequent influence as demonstrators. Copyright 1999 The Association for the Study of Animal Behaviour.     

Influence of nest seclusion and nesting material on pre-laying behaviour of laying hens

Provision of nest sites is beneficial for the welfare of laying hens in intensive production systems. The design of these nest sites has a direct effect on pre-laying behaviour. The aim of this study was to investigate the effects of screening off the entrances of the nest boxes with non-transparent flaps and providing nesting or flooring material on pre-laying behaviour. Eighteen individual Hisex brown laying hens and 18 groups of five hens were tested for 2 days in a test cage containing three nest boxes each with a different nesting material (peat, artificial turf and plastic-coated wire mesh). On one of the days the nest boxes were equipped with plastic flaps at the entrances. Pre-laying behaviour was analysed using focal sampling. Both degree of seclusion and nesting material had an effect on pre-laying behaviour of hens. Nest boxes with flaps were visited less frequently but for a longer duration per visit than nest boxes without flaps. Hens spent more time sitting and scratching, and less time standing and moving when flaps were present. Hens also received fewer pecks (group test) when nest boxes were equipped with flaps. Major differences were found between pre-laying behaviour on coated wire mesh compared to peat and artificial turf with shorter duration of nest visits (group test), more standing (group test) and moving (individual and group test), and less sitting (individual and group test) and object pecking (group test) on coated wire mesh. Differences in pre-laying behaviour on peat versus artificial turf were observed for the behaviours moving (less on peat), sitting (more on peat in the individual test) and object pecking (more on peat in the group test).

It is concluded that hens show more settled pre-laying behaviour and more nest-building behaviour in the presence of flaps at the entrances of nest boxes. These results indicate that seclusion of nest boxes with non-transparent flaps is beneficial to laying hen welfare. Differences in pre-laying behaviour also suggest that plastic-coated wire mesh is less suitable as nesting material than peat and artificial turf.     

The genetic collection of radish inbred lines: history and prospects

The characteristics of a unique genetic collection of radish inbred lines and the history of its creation and study are presented. The possible research prospects are discussed.     

复合酶制剂降解黄曲霉毒素 B1对蛋鸡生产性能和蛋品质的影响

试验旨在研究葡萄糖氧化酶(Glucose Oxidase,GOD)和过氧化氢酶(catalase,CAT)复合酶制剂降解污染饲料中黄曲霉毒素B1(Aflatoxin B1,AFB1)对蛋鸡生产性能和蛋品质的影响。选用210只180日龄京粉蛋鸡,随机分为7组(CK、BA1、BA2、BA3、BD1、BD2和BD3),7个处理组分别是饲喂不添加污染玉米和复合酶的CK组,污染饲料中含有17.22,53.27和134.56μg/kg AFB1的BA1,BA2和BA3组,在有毒玉米中添加0.5%复合酶的BD1、BD2和BD3组。结果显示,蛋鸡的生产性能和蛋品质在BA1、BA2和BA3组均有不同程度下降,在BD1、BD2 3期(T1,T2和T3)和BD3组第1期(T1)均达到对照组水平,BD3组第3期与BA3组同期相比,蛋鸡月产量从9枚提高到17枚,受精蛋孵化率从41%提高到57%,蛋黄重量从14.34 g提高到15.53 g,单枚蛋重从42.39 g提高到48.49g,蛋壳厚度从0.28 mm提高到0.31 mm。由此可知,复合酶制剂基本消除或减轻了AFB1对蛋鸡生产性能和蛋品质不良影响。