This study was conducted to evaluate the effect of early rearing conditions on physiological, haematological and immunological responses relevant to adaptation and long-term stress in white Leghorn hens with intact beaks housed in furnished cages (FC) or conventional cages (CC) during the laying period. Pullets were cage reared (CR) or litter floor reared (FR). From 16 to 76 weeks of age, hens were housed in FC (eight hens per cage) or in CC (three hens per cage). As measures of long-term stress at the end of the laying period, adrenal reactivity was quantified by assessing corticosterone responses to adrenocorticotropin challenge, and immune response was assessed by measuring antibody responses after immunization with sheep red blood cells (SRBC) and keyhole limpet haemocyanin (KLH). Heterophil to lymphocyte (H/L) ratio was employed as an indicator of stress. Rearing conditions significantly affected anti-SRBC titres ( P , 0.0001) and tended to affect H/L ratios ( P 5 0.07), with the highest values found in FR hens. Layer housing affected H/L ratio ( P , 0.01); the highest ratio was found in FR birds housed in FC during the laying period. This study shows that early rearing environment affects immunological indicators that are widely used to assess stress in laying hens. However, while results on H/L ratio indicated that FR birds experienced more stress particularly when they were housed in FC during the laying period, the immune responses to SRBC in FR hens was improved, indicating the opposite. This contradiction suggests that the effects on immune response may have been associated with pathogenic load due to environmental complexity in FR and FC hens rather than stress due to rearing system or housing system per se.Keywords: welfare, housing, rearing, laying hens, adaptation ImplicationsThis study was conducted to explore effects of early pullet rearing conditions on adaptation to furnished cages (FC) during the laying period, which may be a key issue for hen welfare. Physiological, haematological and immunological variables relevant to stress and welfare were measured in birds with intact beaks housed in cages or on the litter floor during rearing, and subsequently in conventional cages or FC during the laying period. Rearing conditions affected variables relevant for hen adaptation. However, it was not evident if the effects were associated with pathogenic load or stress and environmental conditions. IntroductionCurrently, the improvement of laying hen welfare is of great concern to the European Commission and EU egg industry (Council Directive, 1999; EFSA, 2005;Blokhuis et al., 2007). In recent times, there have been concerted research efforts focusing on modifying cage designs and improving hen welfare (Appleby et al., 2002;Blokhuis et al., 2007). A furnished cage system (FC) attempts to provide an enriched environment to meet the behavioural needs of hens while maintaining a small group size to minimize stress (Tauson, 1998). In contrast to the conventional cages (CC), FC are equipped with nesting ar...

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In an experiment including 2400 layers, a diet with 40) whole oats incorporated into 3 mm pellets (experimental diet) was compared with a complete diet, also as 3 mm pellets, but containing no whole oats (control diet). These diets were examined in conventional 3-hens cages and two furnished cage systems with 8 or 16 birds per group including nest, perches and litter. The effects of diet, rearing condition and cage system on performance, plumage condition, comb lesions and rear body wounds were studied. Furthermore, the effect of feed structure on gizzard characteristics and interactions with access to litter during rearing and laying periods were examined. The hybrids LSL and Shaver 2000 were included in the experiment. Egg production was lower (P B0.05) in furnished cages than in conventional cages. No difference in plumage condition was found between diets, but a significantly poorer plumage condition (P B0.05) was observed with increasing group size. Also, the frequencies of rear body (P B0.05) wounds increased as the group sizes increased, while no such effect was observed for comb lesions. Higher (P B0.05) feed consumption was observed in furnished cages than in the conventional, causing a corresponding increase (P B0.05) in feed conversion rate (FCR). Higher (P B0.05) FCR was observed for birds fed pellets with whole oats than the control. Whole oats also increased (P B0.05) the weight of gizzard and gizzard contents. For LSL, better (P B0.05) plumage condition was found for birds reared on a deep litter floor compared to cage rearing. It was concluded that no beneficial effect of replacing high amounts of ground oats with whole oats was observed. Genotype and rearing method may interact with housing system.

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Androstenone is a steroid pheromone occurring in the pubertal Leydig cells. Breeding against androstenone can decrease pheromone odour in swine meat but appears to cause unwanted side effects such as delayed onset of puberty. To study causality, global gene expression in developing boar testes at 12, 16, 20 and 27 weeks was investigated using a porcine cDNA microarray. The morphological status and androgenic levels of the same individuals have been described in a previous publication. In the present paper, expression of genes and pathways has been analysed with reference to these findings. Nine clusters of genes with significant differential expression over time and 49 functional charts were found in the analysed testis samples. Prominent pathways in the prepubertal testis were associated with tissue renewal, cell respiration and increased endocytocis. E-cadherines may be associated with the onset of pubertal development. With elevated steroidogenesis (weeks 16 to 27), there was an increase in the expression of genes in the MAPK pathway, STAR and its analogue STARD6. A pubertal shift in genes coding for cellular cholesterol transport was observed. Increased expression of meiotic pathways coincided with the morphological onset of puberty. Puberty-related change in Ca (2+) pathway transcripts, neurosteroids, neuronal changes and signalling in redox pathways suggested a developmental-specific period of neuromorphogenesis. Several growth factors were found to increase differentially over time as the testis matured. There may be interactions between MAPK, STAR and growth factors during specific periods. In conclusion, pathways for neurogenesis, morphological pathways and several transcripts for growth factors, which have known modulating effects on steroidogenesis and gonadotropins in humans and rodents, act at specific ages and developmental stages in the boar testis. The age dependency and complexity shown for development-specific testis transcripts must be considered when selecting phenotypic parameters for genetic selection for low androstenone. The results of selection based on measurement of phenotypic maturation and androstenone (or other steroid) levels at one specific age may differ depending on the age used. More research is necessary to find the optimal phenotype to use in order to reduce the unwanted side effects.

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