The Effects of the Alteration of the Phenotypic Appeareance and Modifications of the Early Environment on the Welfare of Laying Hens.

227 p.Los animales criados con fines productivos, como las gallinas de puesta, están frecuentemente expuestos a una amplia gamma de desafíos tanto sociales como ambientales desde el día en el que nacen. El objetivo principal de esta Tesis es: explorar los efectos que la alteración del contexto social y ambiental causan sobre el bienestar de las gallinas de puesta.Esta Tesis se divide en dos grandes partes: 1) La primera parte (Capítulos 2 y 3), tiene como objetivo investigar si la alteración de la apariencia fenotípica (AF) de distintas proporciones de aves puede afectar la frecuencia y dirección de sus interacciones sociales. Un segundo objetivo de esta investigación es, determinar si, estos efectos son dependientes del tamaño de grupo (TG) y de la frecuencia del fenotipo alterado dentro del grupo. 2) La segunda parte de esta Tesis (Capítulo 4), explora cómo la provisión de un ambiente complejo (Complex Environment_CENV) durante las primeras etapas de desarrollo, puede preparar mejor a las aves para hacer frente al estrés, e incluso funcionar como un atenuante en frente a episodios estresantes impredecibles que se pueden dar en el futuro. En conclusión, los resultados de esta Tesis proporcionan información importante respecto a las estrategias que pueden adoptar las aves para hacer frente a desafíos tanto sociales como ambientales. Los resultados obtenidos pueden ayudarnos a diseñar ambientes productivos más adaptados y protocolos de manejo que permitan mejorar el bienestar de las gallinas de puesta en condiciones comerciales. Estos resultados tomados en su conjunto destacan la importancia de los inputs sociales y físicos a lo largo de la ontogenia como posibles reguladores de las estrategias para hacer frente al estrés, y de la potencialidad de la respuesta de las gallinas de puestaNeiker; Ikerbasqu

Environmental complexity: A buffer against stress in the domestic chick

Birds kept in commercial production systems can be exposed to multiple stressors from early life and this alters the development of different morphological, immunological and behavioural indicators. We explore the hypothesis that provision of a complex environment during early life, better prepares birds to cope with stressful events as well as buffers them against future unpredictable stressful episodes. In this study, 96 one day old pullets were randomly distributed in eight pens (12 birds/pen). Half of the chicks (N = 48) were assigned to a Complex Environment (CENV: with perches, a dark brooder etc.) the others to a Simple Environment (SENV: without enrichment features). Half of the birds from each of these treatments were assigned to a No Stress (NSTR, 33C) or to an acute Cold Stress (CSTR, 18–20C) treatment during six hours on their second day of life. At four weeks of age, chicks with these four different backgrounds were exposed to an Intermittent Stressful Challenges Protocol (ISCP). In an immunological test indicative of pro-inflammatory status Phytohe-magglutinin-P (PHA-P), the response of CSTR birds was ameliorated by rearing chicks in a CENV as they had a similar response to NSTR chicks and a significantly better pro-inflammatory response than those CSTR birds reared in a SENV (five days after the CSTR treatment was applied). A similar better response when coping with new challenges (the ISCP) was observed in birds reared in a CENV compared to those from a SENV. Birds reared in the CENV had a lower heterophil/lymphocyte ratio after the ISCP than birds reared in SENV, independently of whether or not they had been exposed to CSTR early in life. No effects of stress on general behaviour were detected, however, the provision of a CENV increased resting behaviour, which may have favoured stress recover. Additionally, we found that exposure to cold stress at an early age might have rendered birds more vulnerable to future stressful events. CSTR birds had lower humoral immune responses (sheep red blood cells induced antibodies) after the ISCP and started using elevated structures in the CENV later compared to their NSTR conspecifics. Our study reflects the importance of the early provision of a CENV in commercial conditions to reduce negative stress-related effects. Within the context of the theory of adaptive plasticity, our results suggest that the early experience of the birds had long lasting effects on the modulation of their phenotypes.Fil: Campderrich, Irene. Centro de Investigación. Neiker - Tecnalia; España. Swedish University of Agricultural Sciences; SueciaFil: Nazar, Franco Nicolas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Ciencias y Tecnología de los Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Wichman, Anette. Swedish University of Agricultural Sciences; SueciaFil: Marin, Raul Hector. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Ciencias y Tecnología de los Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Estevez, Inma. Centro de Investigación. Neiker - Tecnalia; EspañaFil: Keeling, Linda J.. Swedish University of Agricultural Sciences; Sueci

Experimental design.

<p>Three different group sizes (GS) were tested (10, 20 and 40) for each original phenotypic appearance (PA) treatment: 100% U (100U), 30% (30M/70U), 50% (50M/50U), 70% (70M/30U), 100% M (100M)). U: Unmarked, M: Marked. Originally heterogeneous groups: 30, 50 and 70% altered from day one were used as controls. Adapted from Marin et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188931#pone.0188931.ref047" target="_blank">47</a>].</p

The looks matter; Aggression escalation from changes in the phenotypic appearance in the domestic fowl

Dataset of aggression among groups of laying hens. Effects of group size and phenotypic appeareance alterations during adulthood

The looks matter; aggression escalation from changes on phenotypic appearance in the domestic fowl

<div><p>Domestic fowl in small groups are assumed to establish hierarchical systems based on individual recognition. Conversely, interactions in large groups are modulated by badges of status. Previous studies suggested that birds differing in phenotypic appearance (PA) became targets for aggression, possibly mistaking altered PA for badges of status. We evaluated the impact of altering PA on 0, 30, 50, 70 or 100% of the birds’ house at three experimental group sizes (GS). Tested GS were 10, 20 or 40 (8 birds/m², 3 pens/GSxPA, 45 total). Thus, for each GS we had groups initially homogenous (100U, U = Unmarked; 100M, M = Marked), or heterogeneous M and U phenotypes coexisting in different proportions: 30M/70U, 50M/50U, and 70M/30U, remaining unchanged until 33 weeks of age. Then, homogeneous groups (100U and 100M) were sequentially altered by marking or unmarking 30, 50 and 70% of birds at 34, 38 and 44 weeks, respectively. Aggressive interactions were observed before applying changes at 27–28 weeks (T0), and after each sequential PA change on week 35–36 (T1), 39–40 (T2) and 45–46 (T3). Frequency of aggressive interactions in altered groups at T1, T2, and T3 were compared with non-altered heterogeneous controls. Results indicate no differences across initial PA and GS treatments (T0; P>0.05). However, aggression escalation was observed at T1 immediately after the first PA manipulation (Tukey P<0.05 altered <i>vs</i> controls). Aggression in altered groups remained high at T2 when compared to controls (Tukey, P<0.05), although by T3 interactions declined to almost initial levels (Tukey, P>0.05 altered <i>vs</i> controls). Aggressive interactions at T1 and T2 were predominantly directed from un-altered towards recently altered birds, irrespectively of their initial phenotype and of the GS. These results demonstrate that a sudden change in PA affects group dynamics. Altered birds were exposed to escalated aggression even in small groups, where individual recognition was presumed.</p></div

Ethogram defining the aggressive interactions recorded: Aggressive pecks, chases, leaps, threats and fights.

<p>Ethogram defining the aggressive interactions recorded: Aggressive pecks, chases, leaps, threats and fights.</p

Directionality of aggressive interactions across time.

<p>M = marked; U = unmarked. Differences between observed and expected aggressive interactions (means ± SE) for each possible interacting pair (MM, MU, UM and UU) and phenotypic appearance (PA) treatment: originally homogeneous (100U, 100M), and controls (30M/70U, 50M/50U, 70M/30U). 3A) T0: 27–28 weeks; 3B) T1: 35–36; 3C) T2:39–40; 3D) T3:45–46. Different letters indicate significant differences among interacting pairs within the same PA treatment.</p

Total aggression (interactions per bird/40 min).

<p>Frequency of total aggression per bird at T0 (27–28 weeks; 1A), T1 (35–36 weeks; 1B), T2 (39–40 weeks; 1C) and T3 (45–46 weeks, 1D). Bars represent means ± SE. M = marked; U = unmarked. Phenotypic appearance (PA) treatments: originally homogeneous (100U, 100M) and controls (30M/70U, 50M/50U, 70M/30U). Different letters denote significant differences among PA treatments at <i>P</i><0.05.</p

Environmental complexity buffers against stress-induced negative judgement bias in female chickens

Abstract Cognitive processes are often biased by emotions. In humans, affective disorders are accompanied by pessimistic judgement, while optimistic judgement is linked to emotional stability. Similar to humans, animals tend to interpret ambiguous stimuli negatively after experiencing stressful events, although the long-lasting impact on judgement bias has rarely been investigated. We measure judgement bias in female chicks (Gallus gallus domesticus) after exposure to cold stress, and before and after exposure to additional unpredictable stressors. Additionally, we explore if brain monoamines can explain differences in judgement bias. Chicks exposed to cold stress did not differ in judgement bias compared to controls, but showed sensitivity to additional stressors by having higher motivation for social reinstatement. Environmental complexity reduced stress-induced negative judgement bias, by maintaining an optimistic bias in individuals housed in complex conditions even after stress exposure. Moreover, judgement bias was related to dopamine turnover rate in mesencephalon, with higher activity in individuals that had a more optimistic response. These results demonstrate that environmental complexity can buffer against negative effects of additive stress and that dopamine relates to judgement bias in chicks. These results reveal that both internal and external factors can mediate emotionally biased judgement in animals, thus showing similarities to findings in humans