Impact of Daily Thermocycles on Hatching Rhythms, Larval Performance and Sex Differentiation of Zebrafish

In the wild, water temperature cycles daily: it warms up after sunrise, and cools rapidly after sunset. Surprisingly, the impact of such daily thermocycles during the early development of fish remains neglected. We investigated the influence of constant vs daily thermocycles in zebrafish, from embryo development to sexual differentiation, by applying four temperature regimens: two constant (24°C and 28°C) and two daily thermocycles: 28:24°C, TC (thermophase coinciding with daytime, and cryophase coinciding with night-time) and 24:28°C, CT (opposite to TC) in a 12:12 h light:dark cycle (LD). Embryo development was temperature-dependent but enhanced at 28°C and TC. Hatching rhythms were diurnal (around 4 h after lights on), but temperature- and cycle-sensitive, since hatching occurred sooner at 28°C (48 hours post fertilization; hpf) while it was delayed at 24°C (96 hpf). Under TC, hatching occurred at 72 hpf, while under CT hatching displayed two peaks (at 70 hpf and 94 hpf). In constant light (LL) or darkness (DD), hatching rhythms persisted with tau close to 24 h, suggesting a clock-controlled "gating" mechanism. Under 28°C or TC, larvae showed the best performance (high growth and survival, and low malformations). The sex ratio was strongly influenced by temperature, as the proportion of females was higher in CT and TC (79 and 83% respectively), contrasting with 28°C and 24°C, which led to more males (83 and 76%). Ovarian aromatase (cyp19a) expression in females was highest in TC and CT (6.5 and 4.6 fold higher than at 28°C, respectively); while anti-müllerian hormone (amh) expression in males increased in testis at 24°C (3.6 fold higher compared to TC) and particularly at 28°C (14.3 fold increase). Taken together, these findings highlight the key role of environmental cycles during early development, which shaped the daily rhythms in fish embryo and larvae, and ultimately influenced sex differentiation

Glucocorticoid receptor (DlGR1) is expressed in pre-larval and larval stages of the teleost fish Dicentrarchus labrax

Glucocorticoid hormone receptors (GR), members of the nuclear hormone receptor superfamily, are ligand-dependent transcription factors expressed in various tissues by binding to specific DNA sequences. Since glucocorticoids have a role in maintaining the homeostatic status in fish, we previously cloned and sequenced a GR (DlGR1) of adult Dicentrarchus labrax; we also showed mRNA expression (in situ hybridization) and tissue immunohistochemical localization of DlGR1 in several organs. This work has now been extended to the examination of the expression, tissue distribution, and cytolocalization of DlGR1 in larval developmental stages by similar methods to those used for the adult organs. The riboprobe included the DlGR1 cDNA transcriptional activation domain (1.0–1,300 nucleotide sequence) showing no significant similarity with a known second GR cDNA sequence of sea bass. The antibody was specific for an opportunely selected peptide sequence of the DlGR1 transcriptional domain. In histological sections of brain, head kidney, gills, liver, anterior intestine, and spleen cells, the riboprobe was mainly located in the cell nucleus. The antibody identified DlGR1 in the head kidney, gills, liver, and anterior intestine, mainly located in the cytosol. These results are in agreement with the receptor location in adult tissues. The greater presence of both the transcript and protein of DlGR1 in the late developmental stages suggests an increasing expression of this receptor. The cytolocalization (nuclear-cytosolic) and presumptive roles of DlGR1-containing tissues are discussed

SENIOR HIGH SCHOOL TRACK PREFERENCES OF GRADE 10 LEARNERS WITH SPECIAL EDUCATIONAL NEEDS (LSENs): A BASIS FOR SCHOOL CAREER GUIDANCE PROGRAM

One of the challenges of grade 10 students is what track to choose in senior high school years. As identified in most of the studies, different factors influence grade 10 learners’ decisions on which senior high school track they ought to pursue, which include personal interest, family influence, peer influence, job opportunities, and financial condition. Embracing the realization of inclusion, learners with special educational needs (LSENs) also experiencing this kind of predicament, the school should be prepared with what support and program they can offer to their learners who are categorized as LSENs for them to choose and decide what senior high school track will they pursue. The purpose of this study is to determine what factors influenced the senior high school track preferences of grade 10 learners with disabilities (LWDs) in a public high school in Cavite, Philippines, and also to know if the health condition of the participants greatly influenced their decision in choosing the senior high school track. In this study, a descriptive design was used, along with a four (4) point Likert scale for each indicator. The grade 10 LWDs of an inclusive public high school in Cavite, Philippines served as participants, and through an online survey questionnaire data was gathered. Data was then interpreted using frequency, ranking, and weighted mean. This study revealed that the LSENs' interests were the most influential factor in their choice of senior high school track while peer influence was the least

Sea bass hatchery operations

A 42-page manual updating AQD's 1990 publication of the same title. It details the activities in the seabass hatchery, from breeding until the harvest and transport of fry to fishponds. New section on the propagation of natural food Moina and Diaphanosoma has been added.The manual addresses sea bass (Lates calcarifer) fry production in the hatchery. It describes the principles and practical procedures for rearing sea bass - from eggs until metamorphosis - as practiced by the SEAFDEC Aquaculture Department in Tigbauan, Iloilo, Philippines. It is presented under the following main section headings: General principles; biology; Selecting a suitable site; Design - tank systems, seawater supply system, freshwater supply system, aeration system, other facilities; Broodstock - source of breeders, breeding techniques; Egg collection, transport and hatching; Larval rearing - stocking density, feed types and feeding management, water management size-grading of larvae; Harvest and transport of fry; and, Propagation of larval food - Chorella, Brachionus, Artemia, Moina.2nd Ed

Hatchery production of snubnose pompano Trachinotus blochii Lacepede

A 26-page extension manual describing the biology, broodstock acquisition & management, larval rearing, harvest & transport and prevention of diseases & parasites in hatchery production of pompano

Phytochemical composition antioxidant and antibacterial activity of the Philippine marine green alga (Ulva pertusa)

The phytochemical constituents, total phenolic and flavonoid contents, antioxidant and antimicrobial activities of the ethanolic extract of the marine green alga Ulva pertusa collected from floating fish net cages off the coast of Guimaras island, Philippines, were investigated. Qualitative phytochemical analysis revealed the presence of bioactive compounds including alkaloids, flavonoids, phenols, saponins, tannins, and terpenoids. Quantitatively, total phenolic and flavonoid contents of the extract were 20.54±2.08 mg gallic acid equivalent (GAE) g-1 and 539.07±6.36 mg rutin equivalent (RE) g-1, respectively. The antioxidant activity of the extract using 1,1-diphenyl-1-picrylhydrazyl (DPPH) assay exhibited a concentration-dependent radical scavenging capacity. Additionally, the ethanolic extract inhibited the growth of Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, Streptococcus agalactiae, Aeromonas hydrophila, A. sobria, and Vibrio harveyi in a concentration-dependent manner with strong inhibitory activity at 100 mg mL-1 concentration. Taken together, U. pertusa contains bioactive compounds that possess potent antibacterial activity and remarkable antioxidant capacities. These substances are promising candidates that may be utilized in the synthesis of novel drugs.This study was funded by the Government of Japan Trust Fund V through the Regional Disease Project (study code: FH01-F2010-T) and partly by SEAFDEC AQD

Changes in iodide and thyroid hormone levels of hatchery-reared orange-spotted rabbitfish Siganus guttatus (Bloch 1787) during early larval development

This paper elucidates the developmental profiles of iodide and thyroid hormones, thyroxine (T4) and triiodothyronine (T3) in hatchery-reared rabbitfish (Siganus guttatus) during early larval development. The study evaluated the levels of iodide, T4 and T3 tissue content in rabbitfish larvae at 0, 10, 20, 30, 40 and 50 days after hatching (DAH). Under normal rearing conditions, iodide (11.98 ± 4.3 nmol g−1) and thyroid hormones (T4: 0.09 ± 0.01 nmol g−1; T3: 0.01 ± 8.5E-05 nmol g−1 were already detected from newly-hatched larvae and their presence has been attributed from maternal origin. Iodide level sharply peaked at 10 DAH (1416.43 ± 149.6 nmol g−1) which is significantly higher compared to the iodide levels in the larvae at 20, 30, 40 and 50 DAH. The levels of THs gradually increased as the larvae developed with T4 (0.96 ± 0.05 nmol g−1) and T3 (0.03 ± 0.004 nmol g−1) exhibiting a peak on 20 and 30 DAH, respectively, which coincided with the onset of metamorphosis. Thyroid hormone levels gradually decreased which coincided also with the completion of metamorphosis. The present findings indicated a pattern of the rise and fall in iodide and thyroid hormone levels during larval development and its role in metamorphosis of rabbitfish larvae. The study has reported for the first time, the changes in iodide and thyroid hormone levels during the early developmental stage in hatchery-reared rabbitfish and the results are in agreement with those vital actions of thyroid hormones in other fish species.This study is part of MS thesis submitted to the University of the Philippines in the Visayas. The authors are grateful to Aquaculture Department Southeast Asian Fisheries Development Center (SEAFDEC/AQD) (Budget Code 5175-T-RD) and Department of Science and Technology-Accelerated Science and Technology Human Resource Development Program (DOST-ASTHRDP) (2000-42924) for providing facilities, resources and funds to the main author to undertake this study. Special thanks to the staff of the Marine Fish Hatchery for the assistance during the conduct of the experiment and to the staff of the Laboratory for Advanced Aquaculture and Technology for the advice and support during laboratory analysis

State-of-the-art of abdominal wall surgery in Italy: coding, reimbursement, hospitalisations and expenditure for surgical meshes

In this chapter, we present the state-of-the-art of abdominal wall surgery in Italy. In 2016, 83,427 hospitalisations for hernia repair were performed by public and private hospitals, the vast majority (87%) without complications. The expenditure for surgical meshes by public hospitals was equal to 21,281 million euro, with a 2.0% increase with respect to 2015. Currently, in Italy patients are classified based on their age, hernia location (inguinal/femoral/other) and presence/absence of complications. Clinical severity (e.g. hernia size), type of hernia (i.e. monolateral, bilateral and recurrent), type of intervention (open surgery vs. laparoscopy) and type of device are not considered. The level of reimbursement for hospitalisations varies across Italian regions. Special payments to encourage the use of innovative devices for hernia repair have not been introduced by any region