The Use of Dietary Additives in Fish Stress Mitigation: Comparative Endocrine and Physiological Responses

In the last years, studies on stress attenuation in fish have progressively grown. This is mainly due to the interest of institutions, producers, aquarists and consumers in improving the welfare of farmed fish. In addition to the development of new technologies to improve environmental conditions of cultured fish, the inclusion of beneficial additives in the daily meal in order to mitigate the stress response to typical stressors (netting, overcrowding, handling, etc.) has been an important research topic. Fish are a highly diverse paraphyletic group (over 27,000 species) though teleost infraclass include around 96% of fish species. Since those species are distributed world-wide, a high number of different habitats and vital requirements exist, including a wide range of environmental conditions determining specifically the stress response. Although the generalized endocrine response to stress (based on the release of catecholamines and corticosteroids) is detectable and therefore provides essential information, a high diversity of physiological effects have been described depending on species. Moreover, recent omics techniques have provided a powerful tool for detecting specific differences regarding the stress response. For instance, for transcriptomic approaches, the gene expression of neuropeptides and other proteins acting as hormonal precursors during stress has been assessed in some fish species. The use of different additives in fish diets to mitigate stress responses has been deeply studied. Besides the species factor, the additive type also plays a pivotal role in the differentiation of the stress response. In the literature, several types of feed supplements in different species have been assayed, deriving in a series of physiological responses which have not focused exclusively on the stress system. Immunological, nutritional and metabolic changes have been reported in these experiments, always associated to endocrine processes. The biochemical nature and physiological functionality of those feed additives strongly affect the stress response and, in fact, these can act as neurotransmitters or hormone precursors, energy substrates, cofactors and other essential elements, implyingmulti-systematic and multi-organic responses. In this review, the different physiological responses among fish species fed stress-attenuating diets based on biomolecules and minerals have been assessed, focusing on the endocrine regulation and its physiological effects

Carbon dioxide fluxes increase from day to night across European streams

Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air interface across 34 European streams. We directly measured fluxes four times between October 2016 and July 2017 using drifting chambers. Median fluxes are 1.4 and 2.1 mmol m−2 h−1 at midday and midnight, respectively, with night fluxes exceeding those during the day by 39%. We attribute diel carbon dioxide flux variability mainly to changes in the water partial pressure of carbon dioxide. However, no consistent drivers could be identified across sites. Our findings highlight widespread day-night changes in fluvial carbon dioxide fluxes and suggest that the time of day greatly influences measured carbon dioxide fluxes across European streams

2024 RECOVER Guidelines: Basic Life Support. Evidence and knowledge gap analysis with treatment recommendations for small animal CPR

ObjectiveTo systematically review evidence and devise treatment recommendations for basic life support (BLS) in dogs and cats and to identify critical knowledge gaps.DesignStandardized, systematic evaluation of literature pertinent to BLS following Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Prioritized questions were each reviewed by 2 Evidence Evaluators, and findings were reconciled by BLS Domain Chairs and Reassessment Campaign on Veterinary Resuscitation (RECOVER) Co-Chairs to arrive at treatment recommendations commensurate to quality of evidence, risk to benefit relationship, and clinical feasibility. This process was implemented using an Evidence Profile Worksheet for each question that included an introduction, consensus on science, treatment recommendations, justification for these recommendations, and important knowledge gaps. A draft of these worksheets was distributed to veterinary professionals for comment for 4 weeks prior to finalization.SettingTransdisciplinary, international collaboration in university, specialty, and emergency practice.ResultsTwenty questions regarding animal position, chest compression point and technique, ventilation strategies, as well as the duration of CPR cycles and chest compression pauses were examined, and 32 treatment recommendations were formulated. Out of these, 25 addressed chest compressions and 7 informed ventilation during CPR. The recommendations were founded predominantly on very low quality of evidence and expert opinion. These new treatment recommendations continue to emphasize the critical importance of high-quality, uninterrupted chest compressions, with a modification suggested for the chest compression technique in wide-chested dogs. When intubation is not possible, bag-mask ventilation using a tight-fitting facemask with oxygen supplementation is recommended rather than mouth-to-nose ventilation.ConclusionsThese updated RECOVER BLS treatment recommendations emphasize continuous chest compressions, conformation-specific chest compression techniques, and ventilation for all animals. Very low quality of evidence due to absence of clinical data in dogs and cats consistently compromised the certainty of recommendations, emphasizing the need for more veterinary research in this area

Acquired nonaccommodative esotropia in childhood

Purpose: Acquired nonaccommodative esotropia (ANAET) in childhood is reported to occur infrequently and is often associated with an underlying neurologic or neoplastic disorder. The primary objective of this study was to ascertain the prevalence and clinical characteristics of this form of childhood esotropia. Methods: A cohort of all children younger than 11 years with esotropia from a predominantly rural Appalachian region was prospectively identified from August 1, 1995, through July 31, 1998. The age at onset, family history of strabismus, perinatal and medical history, ophthalmologic findings, and surgical results were reviewed for all patients with ANAET. Results: Twenty-three (10.4%) of 221 consecutive children with esotropia were diagnosed with ANAET compared with 12 (5.4%) diagnosed with congenital esotropia. The median age at esotropia onset for the 23 children with ANAET was 31.4 months (range, 8-63 months) with a mean initial angle of esotropia of 24 PD. Although at least 2 children presented with diplopia, none of the 23 patients were known to have harbored intracranial tumors or other lesions of the central nervous system during the follow-up period. Fourteen of the 19 patients who underwent surgery attended follow-up visits for at least 6 months after their last surgical procedure: 13 were within 8 PD or less of orthotropia, whereas the final patient had persistent esotropia. Twelve of the 13 patients within 8 PD of orthotropia demonstrated some level of stereopsis, including 2 children with bifoveal fixation. Two (10.5%) of the 19 operated patients later required a low hyperopic spectacle correction to control their deviation. Conclusions: ANAET was more prevalent than congenital esotropia in this cohort of children with esotropia. This clinically distinct form of strabismus typically begins between 1 and 5 years of age and appears to be infrequently associated with underlying disease. The angle of deviation is relatively small and early surgical correction is more likely to achieve bifoveal fixation for these patients than for those with congenital esotropia

Synthetic, structural, and spectroscopic studies of bis(porphyrinzinc) complexes linked by two-atom conjugating bridges

Four Zn-II 5,10,15-triphenylporphyrin (TriPP) complexes meso-meso linked by two-atom bridges, namely, C2H2 (2), C-2 (3), CH= N (4), and N-2 (5), were prepared, for comparison of ground-state inter-porphyrin conjugation. The X-ray crystal structure of azoporphyrin 5 center dot py(2) (py = pyridine) was determined: it exhibits a stepped-offset shape and a porphyrin- azo torsion angle of 34.8 degrees. Some new monoporphyrin starting materials were prepared, and ZnTriPPNH(2) (27), ZnTriPPCHO (23), NiTriPPCHO (7), and ZnTriPPCH(2)CH(2)Ph (18), as well as the byproduct butadiyne-linked dimer 26 were characterized by single-crystal X-ray crystallography. The conjugation in the dimers was assessed by electronic absorption and steady-state fluorescence spectroscopy. All show variously split B bands: azoporphyrin 5 clearly has the strongest ground-state inter-porphyrin interactions. Imine 4 and azo 5 show strongly quenched fluorescence emission, which indicates the presence of efficient relaxation pathways afforded by the N-containing linkers