The Digestive Tract of Cephalopods: a Neglected Topic of Relevance to Animal Welfare in the Laboratory and Aquaculture

Normal development, growth and the maintenance of health and well-being are only possible if all the digestive tract functions (e.g., motility, digestion, and absorption) operate normally and in concert. Understanding the physiological processes and the impact of external factors (e.g., handling, temperature, diet quality including exposure to food toxins, exposure to viral/bacterial infections and parasites) is important for normal laboratory maintenance of the animal in a research setting, as well as for optimizing conditions for aquaculture at each life stage. The study of the physiology of the cephalopod digestive apparatus has mainly focused on Sepia officinalis (Bidder, 1966; Boucaud-Camou and Boucher-Rodoni, 1983; Mangold and Bidder, 1989; Quintela and Andrade, 2002a,b; Sykes et al., 2013; Costa et al., 2014), Octopus vulgaris (Boucher-Rodoni and Mangold, 1977; Boucaud-Camou and Boucher-Rodoni, 1983; Andrews and Tansey, 1983b; Mangold and Bidder, 1989), Octopus maya (Martínez et al., 2011a,b, 2012; Rosas et al., 2013; Linares et al., 2015; Pech-Puch et al., 2016). Few studies have been carried out in Loligo vulgaris and other squid (Bidder, 1950; Mangold and Bidder, 1989). Furthermore, the morphology, motility and absorptive functions of the digestive tract of Nautilus pompilius have been the subject of limited investigation (Westermann and Schipp, 1998a,b, 1999; Ruth et al., 1999; Westermann et al., 2000, 2002). The inclusion of all “live cephalopods,” taken to mean all living species (about 700), at all life stages after hatching, in Directive 2010/63/EU (European Parliament and Council of the European Union, 2010) covering the use of animals in scientific research and education poses a number of challenges for research (Smith et al., 2013; Fiorito et al., 2015) including that aimed at optimizing practices in aquaculture (Sykes et al., 2012; Smith et al., 2013; Fiorito et al., 2015). Whilst the Directive regulates studies in the Member States of the European Union, the principles it enshrines and the approaches to care and welfare required for compliance are likely to impact on cephalopod research outside the European Union (see Fiorito et al., 2014, for discussion of wider implications). In comparison to the commonly studied vertebrate laboratory species and commercially exploited vertebrates such as salmon and trout, chickens, cows, and pigs (Stevens, 1988; Grosell et al., 2010; Rønnestad et al., 2013), knowledge of the physiology of the cephalopod digestive tract at all life stages is limited. Cephalopods are also kept for education and display purposes and, as in the laboratory and aquaculture, the normal functioning of the digestive tract is essential for good health and wellbeing (Fiorito et al., 2015). In this review, we will highlight a number of specific aspects of the relationship between feeding behavior and the physiology of the cephalopod digestive tract where increased understanding is required to ensure animal welfare. We will also discuss areas where further study is required.En prens

The Current State of Cephalopod Science and Perspectives on the Most Critical Challenges Ahead From Three Early-Career Researchers

International audienceHere, three researchers who have recently embarked on careers in cephalopod biology discuss the current state of the field and offer their hopes for the future. Seven major topics are explored genetics, aquaculture, climate change, welfare, behavior, cognition, and neurobiology. Recent developments in each of these fields are reviewed and the potential of emerging technologies to address specific gaps in knowledge about cephalopods are discussed. Throughout, the authors highlight specific challenges that merit particular focus in the near-term. This review and prospectus is also intended to suggest some concrete near-term goals to cephalopod researchers and inspire those working outside the field to consider the revelatory potential of these remarkable creatures

Effects of eight neuropsychiatric copy number variants on human brain structure

peer reviewedMany copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (n = 39/28), 16p11.2 (n = 87/78), 22q11.2 (n = 75/30), and 15q11.2 (n = 72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohen’s d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions. © 2021, The Author(s)

Effects of eight neuropsychiatric copy number variants on human brain structure

Many copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (n = 39/28), 16p11.2 (n = 87/78), 22q11.2 (n = 75/30), and 15q11.2 (n = 72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohen’s d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions

Characterization of Arm Autotomy in the Octopus, Abdopus aculeatus (d'Orbigny, 1834)

Autotomy is the shedding of a body part as a means of secondary defense against a predator that has already made contact with the organism. This defense mechanism has been widely studied in a few model taxa, specifically lizards, a few groups of arthropods, and some echinoderms. All of these model organisms have a hard endo- or exo-skeleton surrounding the autotomized body part. There are several animals that are capable of autotomizing a limb but do not exhibit the same biological trends that these model organisms have in common. As a result, the mechanisms that underlie autotomy in the hard-bodied animals may not apply for soft bodied organisms. A behavioral ecology approach was used to study arm autotomy in the octopus, Abdopus aculeatus. Investigations concentrated on understanding the mechanistic underpinnings and adaptive value of autotomy in this soft-bodied animal.A. aculeatus was observed in the field on Mactan Island, Philippines in the dry and wet seasons, and compared with populations previously studied in Indonesia. Frequency of encountered arm loss and habitat characteristics were recorded and compared between sites, seasons, sex, and arm position. The incidence of autotomy was highest in Indonesia; nearly half of the sampled octopuses were found missing or regenerating arms from the base of the body. Most of the octopuses were male. There was no significant difference in the incidence of autotomy between Indonesia and the Philippines or between the wet and dry seasons in the Philippines. Individuals lost between one and five arms, one arm being the most common. The eight arms from each individual were not equally lost. The anterior pairs of arms were more susceptible to loss due to their function as exploratory arms. The male third right arm used for reproduction was lost less frequently.Attempts to fully describe the behaviors associated with autotomy besides limb detachment have not been made for any organism. Multiple arm autotomy events were observed in A. aculeatus to generate an inventory of behaviors that are characteristic of autotomy. Sequential analysis of these behaviors was conducted and found to follow a particular order during autotomy. Some of the classified behaviors include other secondary defense mechanisms, such as jetting and inking.To understand the mechanism for arm loss at the tissue level, histological sections and force measurements were collected from autotomized arms to characterize the autotomy zone. Individuals were also decerebrated to establish the relative importance of the central nervous system in the occurrence of autotomy. Histology revealed a zone of weakness with no specialized adaptations for loss between proximal suckers four and eight. An average tensile force of 0.645 ± 0.145 MPa was required for autotomy to occur. Eight out of ten decerebrated individuals did not autotomize an arm post-decerebration suggesting that the central nervous system plays a role in arm autotomy.Lastly, the costs and benefits of arm autotomy to A. aculeatus were assessed by studying the effects of arm loss in whole body and autotomized arm locomotion. Individuals with fewer arms were not found to exhibit any negative impact to their crawling or jetting behaviors. The autotomized arms post detachment performed complex behaviors and suctioned to various surfaces for prolonged periods of time suggesting potential adaptations in the arm to distract a predator while the octopus escapes.Overall, the octopus provided a good model system for studying the mechanisms and adaptive value of autotomy in a soft-bodied animal. There multitude of arms were easy to manipulate and induce autotomy in the lab. The relatively high frequency of individuals missing arms in the wild suggest that autotomy plays an important defense role for A. aculeatus and needs further characterization to identify the underlying cause. Efforts to study autotomy in other non-model organisms will broaden and enhance our knowledge on what seems like an extreme, but common defense mechanism

An Ethogram for Benthic Octopods (Cephalopoda: Octopodidae)

The present paper constructs a general ethogram for the actions of the flexible body as well as the skin displays of octopuses in the family Octopodidae. The actions of 6 sets of structures (mantle–funnel, arms, sucker–stalk, skin–web, head, and mouth) combine to produce behavioral units that involve positioning of parts leading to postures such as the flamboyant, movements of parts of the animal with relation to itself including head bob and grooming, and movements of the whole animal by both jetting in the water and crawling along the substrate. Muscular actions result in 4 key changes in skin display: (a) chromatophore expansion, (b) chromatophore contraction resulting in appearance of reflective colors such as iridophores and leucophores, (c) erection of papillae on the skin, and (d) overall postures of arms and mantle controlled by actions of the octopus muscular hydrostat. They produce appearances, including excellent camouflage, moving passing cloud and iridescent blue rings, with only a few known species-specific male visual sexual displays. Commonalities across the family suggest that, despite having flexible muscular hydrostat movement systems producing several behavioral units, simplicity of production may underlie the complexity of movement and appearance. This systematic framework allows researchers to take the next step in modeling how such diversity can be a combination of just a few variables

Youth Development through Veterinary Science, 7: Is Your Bird Feeling Blue?

Part 7 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science

Youth Development through Veterinary Science, 2: Fur, Feathers, Skin and Scales

Part 2 of the Youth Development through Veterinary Science Series, a 4H Youth Development curriculum that introduces youth to many aspects of veterinary science

A 600 kb deletion syndrome at 16p11.2 leads to energy imbalance and neuropsychiatric disorders.

BACKGROUND: The recurrent ~600 kb 16p11.2 BP4-BP5 deletion is among the most frequent known genetic aetiologies of autism spectrum disorder (ASD) and related neurodevelopmental disorders. OBJECTIVE: To define the medical, neuropsychological, and behavioural phenotypes in carriers of this deletion. METHODS: We collected clinical data on 285 deletion carriers and performed detailed evaluations on 72 carriers and 68 intrafamilial non-carrier controls. RESULTS: When compared to intrafamilial controls, full scale intelligence quotient (FSIQ) is two standard deviations lower in carriers, and there is no difference between carriers referred for neurodevelopmental disorders and carriers identified through cascade family testing. Verbal IQ (mean 74) is lower than non-verbal IQ (mean 83) and a majority of carriers require speech therapy. Over 80% of individuals exhibit psychiatric disorders including ASD, which is present in 15% of the paediatric carriers. Increase in head circumference (HC) during infancy is similar to the HC and brain growth patterns observed in idiopathic ASD. Obesity, a major comorbidity present in 50% of the carriers by the age of 7 years, does not correlate with FSIQ or any behavioural trait. Seizures are present in 24% of carriers and occur independently of other symptoms. Malformations are infrequently found, confirming only a few of the previously reported associations. CONCLUSIONS: The 16p11.2 deletion impacts in a quantitative and independent manner FSIQ, behaviour and body mass index, possibly through direct influences on neural circuitry. Although non-specific, these features are clinically significant and reproducible. Lastly, this study demonstrates the necessity of studying large patient cohorts ascertained through multiple methods to characterise the clinical consequences of rare variants involved in common diseases