Short communication: Response of rainbow trout (Oncorhynchus mykiss) to mirror images

The response of cultured rainbow trout to their mirrored image was investigated. Thirty fish were placed individually in two novel aquariums consecutively for 10 min each. Walls in one aquarium were covered with mirrors on all four sides, whereas the walls of the other aquarium were non-transparent black. Because all four walls were covered with mirrors, the mirrored image of the fish was reproduced multiple times such that ‘a group’ of fish was created surrounding the individual. Half of the fish started in the aquarium with the mirrors, whereas the other half started in the mirrorless aquarium. Fish swim faster in the aquarium with mirrors than in the mirrorless aquarium (2.95 vs. 2.40 cm/s; p < 0.01), indicating a positive behavioural response towards their mirrored images. Fish did not show aggressive interactions towards their mirrored images. Being confronted with ‘a group’ of fish and not just one ‘opponent’ may have inhibited aggressive behavior, or individuals may not have considered the images to be fellow individuals. Fish that swam faster in the mirrorless aquarium also did so in the aquarium with mirrors (r = 0.73; p < 0.0001), indicating a persistent behavioural coping response (boldness) in response to the two novel environments. Mirrors may be used to influence social behaviour of fish in aquaculture; further research is needed to investigate the influence of mirror placement in tanks of group housed trout on growth and behaviour

A Hypothesis and Review of the Relationship between Selection for Improved Production Efficiency, Coping Behavior, and Domestication

Coping styles in response to stressors have been described both in humans and in other animal species. Because coping styles are directly related to individual fitness they are part of the life history strategy. Behavioral styles trade off with other life-history traits through the acquisition and allocation of resources. Domestication and subsequent artificial selection for production traits specifically focused on selection of individuals with energy sparing mechanisms for non-production traits. Domestication resulted in animals with low levels of aggression and activity, and a low hypothalamic–pituitary–adrenal (HPA) axis reactivity. In the present work, we propose that, vice versa, selection for improved production efficiency may to some extent continue to favor docile domesticated phenotypes. It is hypothesized that both domestication and selection for improved production efficiency may result in the selection of reactive style animals. Both domesticated and reactive style animals are characterized by low levels of aggression and activity, and increased serotonin neurotransmitter levels. However, whereas domestication quite consistently results in a decrease in the functional state of the HPA axis, the reactive coping style is often found to be dominated by a high HPA response. This may suggest that fearfulness and coping behavior are two independent underlying dimensions to the coping response. Although it is generally proposed that animal welfare improves with selection for calmer animals that are less fearful and reactive to novelty, animals bred to be less sensitive with fewer desires may be undesirable from an ethical point of view

Short communication: Response of rainbow trout (Oncorhynchus mykiss) to mirror images

The response of cultured rainbow trout to their mirrored image was investigated. Thirty fish were placed individually in two novel aquariums consecutively for 10 min each. Walls in one aquarium were covered with mirrors on all four sides, whereas the walls of the other aquarium were non-transparent black. Because all four walls were covered with mirrors, the mirrored image of the fish was reproduced multiple times such that ‘a group’ of fish was created surrounding the individual. Half of the fish started in the aquarium with the mirrors, whereas the other half started in the mirrorless aquarium. Fish swim faster in the aquarium with mirrors than in the mirrorless aquarium (2.95 vs. 2.40 cm/s; p &lt; 0.01), indicating a positive behavioural response towards their mirrored images. Fish did not show aggressive interactions towards their mirrored images. Being confronted with ‘a group’ of fish and not just one ‘opponent’ may have inhibited aggressive behavior, or individuals may not have considered the images to be fellow individuals. Fish that swam faster in the mirrorless aquarium also did so in the aquarium with mirrors (r = 0.73; p &lt; 0.0001), indicating a persistent behavioural coping response (boldness) in response to the two novel environments. Mirrors may be used to influence social behaviour of fish in aquaculture; further research is needed to investigate the influence of mirror placement in tanks of group housed trout on growth and behaviour

Allometric scaling of the elevation of maternal energy intake during lactation

In most mammals, lactating mothers dramatically increase their food intake after parturition and reach a peak intake rate after a certain time while their offspring continue to grow. A common view, perpetuated by the metabolic theory of ecology, is that the allometric scaling of maternal metabolic rate with body mass limits the changes in energy intake and expenditure. Therefore these potential effects of metabolic scaling should be reflected in the elevation of maternal energy intake during lactation. To test this hypothesis, we collected published data on 24 species (13 domesticated) and established scaling relationships for several characteristics of the patterns of energy intake elevation (amplitude of the elevation, time to peak, and cumulative elevation to peak). A curvilinear allometric scaling relationship with maternal body mass (in double-logarithmic space) was found for the amplitude of maternal energy intake elevation, similarly to what has been observed for scaling relationships of basal metabolic rate in non-breeding mammals. This result indirectly supports the metabolic theory of ecology. However, this curvilinear allometric scaling does not seem to drive the scaling relationships found for the other characteristics of maternal energy intake. Both the duration and shape of the energy intake patterns showed substantial variation independently of species’ body mass. Data available for a few mammals, mostly domesticated, provides little evidence for the hypothesis that a single law of metabolic scaling governs the elevation of maternal energy intake after parturition. Obtaining further food intake data in wild species will be crucial to unravel the general mechanisms underlying variation in this unique adaptation of mammalian females

Haplotype phasing after joint estimation of recombination and linkage disequilibrium in breeding populations

A novel method for haplotype phasing in families after joint estimation of recombination fraction and linkage disequilibrium is developed. Results from Monte Carlo computer simulations show that the newly developed E.M. algorithm is accurate if true recombination fraction is 0 even for single families of relatively small sizes. Estimates of recombination fraction and linkage disequilibrium were 0.00 (SD 0.00) and 0.19 (SD 0.03) for simulated recombination fraction and linkage disequilibrium of 0.00 and 0.20, respectively. A genome fragmentation phasing strategy was developed and used for phasing haplotypes in a sire and 36 progeny using the 50 k Illumina BeadChip by: a) estimation of the recombination fraction and LD in consecutive SNPs using family information, b) linkage analyses between fragments, c) phasing of haplotypes in parents and progeny and in following generations. Homozygous SNPs in progeny allowed determination of paternal fragment inheritance, and deduction of SNP sequence information of haplotypes from dams. The strategy also allowed detection of genotyping errors. A total of 613 recombination events were detected after linkage analysis was carried out between fragments. Hot and cold spots were identified at the individual (sire level). SNPs for which the sire and calf were heterozygotes became informative (over 90%) after the phasing of haplotypes. Average of regions of identity between half-sibs when comparing its maternal inherited haplotypes (with at least 20 SNP) in common was 0.11 with a maximum of 0.29 and a minimum of 0.05. A Monte-Carlo simulation of BTA1 with the same linkage disequilibrium structure and genetic linkage as the cattle family yielded a 99.98 and 99.94% of correct phases for informative SNPs in sire and calves, respectively

Sustainable development in circular agriculture: An illustrative bee↺legume↺poultry example

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188 Prospects of Swine Production in the Context of Climate Change

1 Pág. Instituto Nacional de Investigación Agraria y AlimentariaPig production systems provide multiple benefits to humans. However, the global increase in meat consumption has profound consequences for our earth, including the use of finite natural resources (land, water, and energy), pollution of watercourses, loss of biodiversity, and contribution to climate change. Pig production practices contribute to climate change through greenhouse gas production associated with manure management and feed production. Novel feed resources that provide a wide range of ecosystem services in mixed cropping, crop rotation, circular agriculture, or circular economy can improve sustainability of pig production practices. Vice versa, global warming has profound consequences for pig production through the negative consequences of heat stress on production efficiency, growth rates, and increased health care costs. Research suggests that pigs that are better adapted to heat stress are better able to maintain growth when intake becomes restricted. These appear to be animals with lower growth rates during thermoneutral conditions. During heat stress, pigs become more feed efficient; however, reduced growth rates result in decreased slaughter weights or increased days on farm, thus reducing production efficiency. Furthermore, heat stress is found to alter the growth trajectory (maturation rate and mature body weight), tissue accretion rates, and carcass composition, and negatively impacts animal health and welfare. The impact of heat stress can be mediated through control strategies of the thermal environment using precision livestock techniques. In addition, because response to heat stress shows variation, these results emphasize the necessity to review breed choice and genetic selection objectives for improved heat tolerance to climate change. Pigs of interest as selection candidates may be those that are able to maintain high growth rates under heat stress, and these may not be the genetics with highest growth potential under environmentally neutral or favorable conditions.Peer reviewe

Vector space algebra for scaling and centering relationship matrices under non-Hardy-Weinberg equilibrium conditions

Agricultural Research Service (ARS) held a joint animal health research planning workshop with the National Institute of Food and Agriculture (NIFA).Scales are linear combinations of variables with coefficients that add up to zero and have a similar meaning to "contrast" in the analysis of variance. Scales are necessary in order to incorporate genomic information into relationship matrices for genomic selection. Statistical and biological parameterizations using scales under different assumptions have been proposed to construct alternative genomic relationship matrices. Except for the natural and orthogonal interactions approach (NOIA) method, current methods to construct relationship matrices assume Hardy-Weinberg equilibrium (HWE). The objective of this paper is to apply vector algebra to center and scale relationship matrices under non-HWE conditions, including orthogonalization by the Gram-Schmidt process.Generation of these data was supported by the USDA ARS and NIFA award 2013-68004-20362. WMR and LGR acknowledge financial support from (1) the Salvador de Madariaga program of the Ministry of Education of Spain, (2) SusAn ERA‐Net project “Sustainability of pig production through improved feed efficiency”, an ERA‐Net co-funded under the European Union’s Horizon 2020 research and innovation programme, under Grant Agreement no 696231, and (3) project AGL2016‐75942‐R, “Caracterización molecular de la eficiencia alimentaria y de los caracteres reproductivos en cerdo Ibérico.”Peer reviewed18 Pág. Departamento de ​Mejora Genética Anima