Natural cortisol production is not linked to the sexual fate of European sea bass

Fish Physiology and Biochemistry - In this study, we aimed to investigate the relationship between cortisol and the determination of sexual fate in the commercially important European sea bass...     

Dynamic regulation of larval fish self‐recruitment in a marine protected area

The factors that regulate the self‐recruitment of fish larvae were explored in Cabrera National Park (CNP), an insular Marine Protected Area (MPA) located off southern Mallorca (Western Mediterranean). Our study attributes the regulation of larval arrival to the MPA to a combination of retention by topographically generated circulation patterns around the island and shelf break frontal dynamics. Specifically, within the shelf, interaction of the wind‐induced oscillatory flow with the island was shown to generate ephemeral recirculation patterns that, over time, favor larval retention in the proximity of the MPA. According to our measurements, oscillatory flows produced by wind‐forced island‐trapped waves (ITWs) dominate the flow around CNP. ITW‐forced dispersion simulations were in agreement with the observed distributions of several typical fish species that breed in the CNP. A second regulator of environmental variability is the influence of boundary currents and open ocean mesoscale structures at the shelf break. These structures generate frontal zones that are comparatively more long‐lived than inner‐shelf circulation patterns, and they were shown to act as barriers to the offshore dispersion of coastal fish larval assemblages. Finally, inferences from larval size distributions around the MPA together with particle‐tracking model simulations suggested the relevance of behavioral processes for larval recruitment to the MPA. Based on these observations, the waters around the CNP can be viewed as a relatively stable system that allows breeding fish populations to rely on self‐recruitment for their long‐term persistence, independent of other source populations along the coast of Mallorca.     

Determination of serum biochemical reference intervals for the Iberian lynx (Lynx pardinus)

Biochemical reference intervals were determined for 31 clinically healthy Iberian lynxes (Lynx pardinus) between 1 and 6 years of age. Thirteen of the lynxes were wild-caught and the other 18 were captive-reared animals. The samples were collected between November 2004 and December 2006. The influence of sex (males vs. females), age (juveniles vs. adults) and habitat condition (free-living vs. captive) on the biochemical analytes were evaluated. Serum albumin concentrations were significantly higher in females than in males, while creatine phosphokinase was higher in males. The levels of alkaline phosphatase and lactate dehydrogenase were higher in juvenile lynxes, while gamma glutamyl-transferase and creatinine values were higher in adults. Lynxes captured in the wild had higher concentrations of iron, calcium, alkaline phosphatase and creatinine, but lower aspartate aminotransferase and alanine aminotransferase than lynxes maintained in captivity. The results were generally comparable to commonly reported reference intervals for other lynx species, the domestic cat and other felid species.     

Migration performance of wild and hatchery sea trout (Salmo trutta L.) smolts—Implications for compensatory hatchery programs

Migration success of hatchery-reared and wild sea trout smolts through the lower stretches and the estuary of a Baltic Sea river were studied. During 3 years, wild and hatchery trout smolts were implanted with acoustic transmitters and released 14 km upstream from the river mouth. In order to monitor their out-migration pattern, acoustic receivers were deployed along the migratory route. Data on number of fish detected and date and time of detections were analysed and the migratory performance of wild and hatchery-reared fish was compared. A significantly higher proportion of wild fish (80%) successfully migrated to the coast compared to fish of hatchery origin (27.5%) and migration was faster in wild smolts. Hatchery fish were larger and had a higher condition factor and lipid concentrations, which are proposed as possible reasons for the poorer migratory performance of the hatchery-reared fish.     

Peanut yield,nutrient uptake and nutrient requirements in different regions of China

Nutrient balance is essential for attaining high yield and improving profits in agricultural farming systems, and crop nutrient uptake ratio and stoichiometry can indicate crop nutrient limitations in the field. We collected a large amount of field data to study the variations in yield, nutrient uptake and nutrient stoichiometry of peanut(Arachis hypogaea L.) in Southeast China(SEC), North-central China(NCC), and Northeast China(NEC), during 1993 to 2018. Peanut pod yield gradually increased from 1993 to 2018, with average yields of 4 148, 5 138, and 4 635 kg ha–1 in SEC, NCC, and NEC, respectively. The nitrogen(N) internal efficiency(NIE, yield to N uptake ratio) was similar among the three regions, but phosphorus(P) IE(PIE, yield to P uptake ratio) changed from low to high among regions: NCCSECNEC, while potassium(K) IE(KIE, yield to K uptake ratio) portrayed a different pattern of SECNCCNEC. Based on the nutrient IE, to produce 1 Mg of pod yield, the average N, P, and K requirements of the above-ground parts of peanut were roughly 47.2, 5.1, and 25.5 kg in SEC, 44.8, 5.7, and 20.6 kg in NCC, and 44.6, 4.4, and 14.7 kg in NEC, respectively. The N/P ratio changed in the sequence NCCSECNEC, and the N/K ratio was similar in NEC and NCC, but lower in SEC. The N harvest index(HI) and KHI declined with increasing nutrient uptake across all regions under high nutrient uptake. The low PIE and N/P ratios in NCC could be explained by the high P accumulation in stover, and high KIE and N/K ratios in NEC may be attributed to the low soil K supply. The frontier analysis approach provides a practical framework and allows documentation of a decline in nutrient HI as nutrient uptake increases. Lastly, this study reveals the limitation and surplus of nutrients of peanut in different regions of China.     

Electrocardiographic parameters in the clinically healthy Zamorano-leones donkey

Limited information exists regarding electrocardiographic parameters in clinically healthy donkeys. The study was carried out in 75 healthy adult animals (40 females and 35 males) using the Einthoven standard II and base-apex leads. The P wave showed usually a bifid shape deflection. The QRS complex of the donkeys appeared in several forms: QR and R were the most frequent in limb lead II, and QS and QR in the base-apex lead. Most T waves presented a simple negative configuration in lead II and biphasic shape in the base-apex one. Mean heart rate value was 52 beats per minute. The direction of the QRS vector in lead II had a mean value of 91.4°. We observed a lack of detected arrhythmias. Statistically significant differences were observed between sexes for several parameters. The electrocardiogram of Zamorano-leones donkey differs in several duration, amplitude and morphologic parameters from that of several breeds of horses and donkeys. This fact justifies obtaining values for a specific breed against which to compare values for the same breed.     

Detection and clinical evolution of scrapie in sheep by 3rd eyelid biopsy

The goal of this article was to characterize the clinical evolution of scrapie in naturally affected sheep. Eighteen sheep with scrapie diagnosed by examination of 3rd eyelid biopsy and 12 control ewes were studied throughout the duration of their disease. Diagnosis was confirmed postmortem by histopathologic, immunohistochemical, and Western blot analysis of nervous tissue. Complete clinical examinations were performed every 2 weeks for each animal, of which 3 clinical examinations per animal are reported. Those clinical signs that showed a significant frequency within the corresponding clinical examination were considered representative of each stage of the disease (ie, early, middle, and late). The representative clinical signs for the early stage were hypoesthesia in the limbs, alteration of mental status, and a body condition score <3. Remarkably, hypoesthesia in the limbs was one of the 1st signs appearing during the early clinical stage in the affected animals, even before the appearance of other signs. For the middle stage, representative signs were the same as those for the early stage, together with hyporreflexia in the limbs, cardiac arrhythmia, pruritus/wool loss, and the appearance of the nibbling reflex. Representative clinical signs for the late stage were the same as those for the early and middle stage, together with head tremors, hyperexcitability to external stimuli, ataxia or gait abnormalities, and teeth grinding. On the basis of these results, we propose the calculation of an objective clinical index that allows the differentiation among clinical stages and that could be useful for further studies. The usefulness of 3rd eyelid lymphoid tissue biopsies for sequential clinical studies in naturally scrapie-affected sheep is demonstrated.     

Induced spermiation of Pimelodus britskii (Teleostei: Pimelodidae) during the reproductive period

For the first time was characterized the semen of Pimelodus britskii, hormonally induced and non‐induced induced, during the reproductive period. The experiment 1 was conducted with 12 fish per month, divided into: (i) induced with Carp Pituitary Extract (CPE), and (ii) without hormonal induction (testes macerated). The experiment 2 was conducted, with 30 fish, divided into groups for comparison of different doses of CPE and human Chorionic Gonadotrophin (hCG; T1: control; T2: 3.0 mg kg^?1 CPE; T3: 0.5 mg kg + 3.0 mg kg^?1 CPE; T4: 0.5 mg kg^?1 + 7.0 mg kg^?1 CPE; T5: 200 UI kg^?1 hCG), the same fish were used every month, and the semen was collected by abdominal massage. In both, experiments were assessed the sperm motility and velocity by means of the CASA software. In experiment 1, the concentration of spermatozoids was significantly increase by application of CPE compared untreated males. The volume and motility decreased gradually until the end of the experiment, the highest values were recorded for treatment induced (0.49 ± 0.25 mL and 62.18, respectively). The same occurred to Gonadosomatic Index, showing the smallest value at the end of the reproductive period. The fish from experiment 2 released reduced volume of watery semen (0.1 mL). The values of sperm concentration, motility velocity decreased gradually throughout the months. For P. britskii, the reproductive period influenced the production and sperm quality. Despite small seminal volume released the dose of 7.5 mg kg^?1 of CPE proved effective.     

EuMIXFOR empirical forest mensuration and ring width data from pure and mixed stands of Scots pine (<Emphasis Type="Italic">Pinus sylvestris L.</Emphasis>) and European beech (<Emphasis Type="Italic">Fagus sylvatica L.</Emphasis>) through Europe

Key message

This data set provides unique empirical data from triplets of Scots pine ( Pinus sylvestris L.) and European beech ( Fagus sylvatica L.) across Europe. Dendrometric variables are provided for 32 triplets, 96 plots, 7555 trees and 4695 core samples. These data contribute to our understanding of mixed stand dynamics. Dataset access at   http://dx.doi.org/10.5061/dryad.8v04m . Associated metadata available at https://metadata-afs.nancy.inra.fr/geonetwork/apps/georchestra/?uuid=b3e098ca-e681-4910-9099-0e25d3b4cd52&hl=eng .