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- Bessa Ferreira, Vitor Hugo, et al.
(författare)
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Foraging Behavior Shows Individual-Consistency Over Time, and Predicts Range Use in Slow-Growing Free-Range Male Broiler Chickens
- 2022
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Ingår i: Frontiers in Veterinary Science. - : Frontiers Media SA. - 2297-1769. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Recent research on free-range chickens shows that individual behavioral differences may link to range use. However, most of these studies explored individual behavioral differences only at one time point or during a short time window, assessed differences when animals were out of their social group and home environment (barn and range), and in specific tests or situations. Therefore, it is yet unclear how different behaviors relate to range use and how consistent these behaviors are at the individual level. To fill this gap, we here aimed to describe the behavioral budget of slow-growing male broiler chickens (S757N) when in their social group and home environment during the whole rearing period (from the second week of life to the twelfth week, before slaughter), and to relate observed behavioral differences to range use. For this, we followed a sample of individuals in two flocks (n = 60 focal chickens out of 200 chickens per flock), over two seasons, during three periods: before range access (from 14 to 25 days old), during early range access (first weeks of range access, from 37 to 53 days old), and during late range access (last weeks of range access, from 63 to 87 days old). By the end of each period, individual tests of exploration and social motivation were also performed, measuring exploration/activity and sociability propensities. Our results show that foraging (i.e., pecking and scratching at the ground) was the only behavior that correlated to range use for all three rearing periods, independent of the season. Foraging was also the only behavior that showed within-individual consistency from an early age and across the three rearing periods. Foraging may, therefore, serve as a useful behavioral predictor of range use in free-range broiler chickens. Our study increases the knowledge of how behaviors develop and relate to each other in a domesticated and intensely selected species, and improves our understanding of the biology of free-range broiler chickens. These findings can, ultimately, serve as a foundation to increase range use and improve chicken welfare.
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| 2. |
- Bonnefous, Claire, et al.
(författare)
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Behavioural indicators of range use in four broiler strains
- 2023
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Ingår i: Applied Animal Behaviour Science. - : ELSEVIER. - 0168-1591 .- 1872-9045. ; 260
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Tidskriftsartikel (refereegranskat)abstract
- Free-range systems provide an outdoor range for broilers to give them the possibility to express a higher frequency and a wider range of behaviours, such as exploration, compared with those raised indoors. Greater variability in outdoor range use between individuals of the same flock is often reported. Individual variation in range use may result from differences in early-life behaviour or genetic background. Understanding how earlylife behaviour influences range use may provide opportunities to enhance and predict range use. Previous studies have shown that range use could be influenced by the animals personality traits such as social motivation, boldness and foraging motivation. Therefore, this study investigated personality traits in several broiler strains, namely Hubbard JA757, Hubbard S757N, White Bresse and a dual-purpose strain; we examined the latter as it represents a potential solution to the ban of 1-day-old chick culling. The present study also investigated early-life behaviours, before range access, of range use to identify and assess the stability of these early-life indicators among the four broiler strains. For that purpose, we recorded the behaviour and range use of 100 male chickens per strain, both in the barn and during individual tests, before and after range access. We examined which behaviours were time consistent, whether early-life behaviours were influenced by genetic variation and whether early-life behavioural indicators predicted range use regardless of genetic variation. There was a significant (p < 0.001) difference between strains in several early-life behaviours, including the time spent resting or standing. Range use was time consistent regardless of the strain as our range use indicator followed a high-quality linear regression model (R-2 > 0.7) for 82-99% of the individuals depending on their strain. Besides, time consistency of social motivation and boldness seemed to depend on the strain. Even though foraging showed low (rho = 0.2-0.4) positive correlations with range use in three of the four studied strains, there were no significant and strong correlations in the four studied strains between early-life behavioural indicators and range use. In conclusion, our results show that the link between chick behaviour (before range access) and range use can be modulated by the birds strain. It is crucial to consider all these different factors to better understand how range use varies within and between flocks.
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| 3. |
- Richards, Stephen, et al.
(författare)
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Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Tidskriftsartikel (refereegranskat)abstract
- Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
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| 4. |
- Villasenor, Roberto, et al.
(författare)
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Trafficking of Endogenous Immunoglobulins by Endothelial Cells at the Blood-Brain Barrier
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The Blood-Brain Barrier (BBB) restricts access of large molecules to the brain. The low endocytic activity of brain endothelial cells (BECs) is believed to limit delivery of immunoglobulins (IgG) to the brain parenchyma. Here, we report that endogenous mouse IgG are localized within intracellular vesicles at steady state in BECs in vivo. Using high-resolution quantitative microscopy, we found a fraction of endocytosed IgG in lysosomes. We observed that loss of pericytes (key components of the BBB) in pdgf-b(ret/ret) mice affects the intracellular distribution of endogenous mouse IgG in BECs. In these mice, endogenous IgG was not detected within lysosomes but instead accumulate at the basement membrane and brain parenchyma. Such IgG accumulation could be due to reduced lysosomal clearance and increased sorting to the abluminal membrane of BECs. Our results suggest that, in addition to low uptake from circulation, IgG lysosomal degradation may be a downstream mechanism by which BECs further restrict IgG access to the brain.
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