Sperm activation in Nile tilapia Oreochromis niloticus and the effects of environmentally relevant pollutants on sperm fitness

In externally fertilizing fishes, multiple factors of the spawning environment may affect the sperm viability, and thus the fertilization rate. In this thesis, the sperm activation effect of osmolality of non-electrolytes and electrolytes activation media, pH and ion channel inhibitors on Nile tilapia, Oreochromis niloticus, and the effect of environmentally relevant pollutants (cadmium, malathion and rotenone) on sperm fitness (motility and morphology) were investigated. Seminal fluid samples collected from male fishes (200-250g) were subjected to activation treatments, then analyzed for sperm motility using motility score, and motility variables using Hobson sperm tracker for straight line velocity (VSL), beat cross frequency (BCF) and percentage of motile cells (MOT). For the ion channel inhibitors and pollutants, the effect on sperm motility variables of VSL, VCL (curvilinear velocity) and LIN (linearity) were determined. Multivariate analysis was also carried out to determine the effects of ion channel inhibitors and pollutants on sperm subpopulations. The effects of pollutants on sperm morphology were observed using microscopy techniques, namely, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Sperm motility was initiated when the sperm were exposed to hypoosmotic electrolytes and non-electrolytes solution. We also found that sperm show optimal activity at pH range of 6-8 which depicts that the effect of pH on sperm motility is negligible. Lanthanum (calcium channel blocker) and flunarizine (sodium-calcium exchanger pump blocker) were found to inhibit sperm motility at 25 and 5 µM, respectively, suggesting that both ion channels play a significant role in sperm activation in O. niloticus. In contrast amiloride, ouabain and quinine showed no effects on activation, indicating that epithelial sodium channels, sodium-potassium ATPase and voltage gated potassium channels respectively are unlikely to have major roles in sperm activation or motility. The spermatozoa of Oreochromis niloticus were uniflagellate with clearly differentiated oval-shaped head, midpiece and flagellum. Sperm exposed to hypoosmotic shock showed swelling of the midpiece and sleeve structure. The pollutants showed dose- and time-dependent effect on sperm motility of the fast linear sperm subpopulation. Sperm morphology was not affected. Sperm motility was inhibited at 0.44, 0.03 and 0.063 µM, cadmium, malathion and rotenone respectively. Both cadmium and malathion exerted effects very quickly after exposure. The effect of cadmium, which can exert toxicity by calcium antagonism, is consistent with the effects of calcium channel blockes and further supports an important role for calcium in sperm activation and motility. Malathion had effects at relatively low, environmentally relevant concentrations, suggesting the presence of functionally important acetylcholinesterase activity in sperm, and also the presence of activation cytochrome P450 activity. Rotenone, a well known mitochondrial poison, affected motility only after 15 min of pretreatment. The alteration of sperm trajectories in fast linear spermatozoa subpopulation by pollutants at submicromolar concentrations as demonstrated in our study implies potentially serious consequences for fish populations in polluted environments. Furthermore the results indicate that fish sperm motility as assessed by CASA could be an ecologically relevant, sensitive, and ethically acceptable method for toxicity testing in environmental risk assessment

Sperm activation in Nile tilapia Oreochromis niloticus and the effects of environmentally relevant pollutants on sperm fitness

In externally fertilizing fishes, multiple factors of the spawning environment may affect the sperm viability, and thus the fertilization rate. In this thesis, the sperm activation effect of osmolality of non-electrolytes and electrolytes activation media, pH and ion channel inhibitors on Nile tilapia, Oreochromis niloticus, and the effect of environmentally relevant pollutants (cadmium, malathion and rotenone) on sperm fitness (motility and morphology) were investigated. Seminal fluid samples collected from male fishes (200-250g) were subjected to activation treatments, then analyzed for sperm motility using motility score, and motility variables using Hobson sperm tracker for straight line velocity (VSL), beat cross frequency (BCF) and percentage of motile cells (MOT). For the ion channel inhibitors and pollutants, the effect on sperm motility variables of VSL, VCL (curvilinear velocity) and LIN (linearity) were determined. Multivariate analysis was also carried out to determine the effects of ion channel inhibitors and pollutants on sperm subpopulations. The effects of pollutants on sperm morphology were observed using microscopy techniques, namely, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Sperm motility was initiated when the sperm were exposed to hypoosmotic electrolytes and non-electrolytes solution. We also found that sperm show optimal activity at pH range of 6-8 which depicts that the effect of pH on sperm motility is negligible. Lanthanum (calcium channel blocker) and flunarizine (sodium-calcium exchanger pump blocker) were found to inhibit sperm motility at 25 and 5 µM, respectively, suggesting that both ion channels play a significant role in sperm activation in O. niloticus. In contrast amiloride, ouabain and quinine showed no effects on activation, indicating that epithelial sodium channels, sodium-potassium ATPase and voltage gated potassium channels respectively are unlikely to have major roles in sperm activation or motility. The spermatozoa of Oreochromis niloticus were uniflagellate with clearly differentiated oval-shaped head, midpiece and flagellum. Sperm exposed to hypoosmotic shock showed swelling of the midpiece and sleeve structure. The pollutants showed dose- and time-dependent effect on sperm motility of the fast linear sperm subpopulation. Sperm morphology was not affected. Sperm motility was inhibited at 0.44, 0.03 and 0.063 µM, cadmium, malathion and rotenone respectively. Both cadmium and malathion exerted effects very quickly after exposure. The effect of cadmium, which can exert toxicity by calcium antagonism, is consistent with the effects of calcium channel blockes and further supports an important role for calcium in sperm activation and motility. Malathion had effects at relatively low, environmentally relevant concentrations, suggesting the presence of functionally important acetylcholinesterase activity in sperm, and also the presence of activation cytochrome P450 activity. Rotenone, a well known mitochondrial poison, affected motility only after 15 min of pretreatment. The alteration of sperm trajectories in fast linear spermatozoa subpopulation by pollutants at submicromolar concentrations as demonstrated in our study implies potentially serious consequences for fish populations in polluted environments. Furthermore the results indicate that fish sperm motility as assessed by CASA could be an ecologically relevant, sensitive, and ethically acceptable method for toxicity testing in environmental risk assessment.EThOS - Electronic Theses Online ServiceGovernment of MalaysiaGBUnited Kingdo

First detection of white spot syndrome virus (WSSV) in wild mud crab Scylla spp. (de Haan, 1883) from Setiu Wetlands, Malaysia

In this study, tissue samples from 90 wild mud crabs (Scylla spp. including S. olivacea, S. Tranquebarica, and S. paramamosain) were collected during pre-monsoon, monsoon, and post-monsoon in the Setiu Wetlands, Terengganu, Malaysia. The tissue samples were screened for the presence of white spot syndrome virus (WSSV) by PCR. This study was conducted to detect the presence or absence of WSSV in wild Scylla spp. from the Setiu Wetlands at different times of sampling. WSSV DNA was detected in 36% of the mud crabs. The DNA sequence of a 941 bp genome region amplified from a crab by PCR was identified to be most similar (99% nucleotide sequence, 98% amino acid sequence) to a WSSV strain detected in Mexico (KU216744.1) and Taiwan WSSV 419 strain (AY850066.1). The data indicated that mud crabs in the Setiu Wetlands might act as a WSSV reservoir of risk to shrimp aquaculture. Our findings are the first detection of WSSV from wild mud crabs, Scylla spp. in the Setiu Wetlands, Terengganu, Malaysia

The application of microalgae feeding regime on whiteleg shrimp culture in each stage : a mini review

Feed management in shrimp culture aims to improve the quality of shrimp organisms. The application of the feeding regime in shrimp culture has been developed to determine the best formulation of diet in order to maximize growth rate and survival rate of shrimp by increasing feed efficiency and minimizing waste. The application of the feeding regime is closely related to the understanding of the physiological and morphological aspects of shrimp from the larval stage to the adult stage. The success of the application of feed management with the application of the feeding regime will be a solution to the problem of the high costs of feed needed in shrimp culture. The best formulation of diet in shrimp culture in the N6-P3 stage is microalgae, at the M1-PL10 stage is zooplankton, and in the juvenileadult shrimp stage is artificial feed. Microalgae can significantly increase the survival rate and growth rate of shrimp at the hatchery stage. This article aimed to examine the effect of the application of feeding regime using different diet formulations to produce the highest growth performance of shrimp in shrimp culture based on the morphological and physiological aspects of shrimp

Quantitative Comparisons of Erythrocyte Morphology in Healthy Freshwater Fish Species from Malaysia

Abstract: Erythrocyte morphology of four freshwater fish species namely tilapia Oreochromis niloticus, Pangasius sutchi, catfish Clarias sp. and river catfish Mystus nemurus were studied. Variations of erythrocyte and nucleus size were observed among the fish species studied. The largest size of erythrocyte was observed in tilapia O.reochromis niloticus (60.79±3.00 µm ) and the smallest size of erythrocyte was observed in catfish 2 Clarias sp., (53.24±2.57 µm ) while the largest size of nucleus was also observed in O.reochromis 2 niloticus (12.18±0.70 µm ) yet smallest in P, sutchi, (9.37±0.97µm) . 2

In vitro and in vivo characterisations of Centella asiatica extract against Vibrio alginolyticus infection in whiteleg shrimp, Penaeus vannamei

Methanolic leaf extracts of the medicinal herb Centella asiatica (Asiatic pennywort) were screened for in vitro and in vivo antimicrobial activities against Vibrio alginolyticus isolated from whiteleg shrimp, Penaeus vannamei. Phytochemical analyses were positive for tannins, saponins, steroids, and cardiac glycosides. Antioxidant test revealed antioxidant activity nearly as potent as that of 0.8 mg/mL ascorbic acid. Minimum inhibitory and bactericidal concentrations against V. alginolyticus were determined to be 0.79 and 12.50 mg/mL respectively. Scanning electron microscopy demonstrated disruptions of treated bacterial cells. 30 mg/kg extract supplementation achieved 85% survival of juvenile shrimp in a feeding trial. Histopathology showed increasingly fewer alterations in hepatopancreas from 10, 20 to 30 mg/kg supplementation, where 30 mg/kg preserved the tissues most with relatively complete structure including the star-shaped tubule lumen and various cell types. The present findings suggest the potential of C. asiatica as an alternative antimicrobial agent against V. alginolyticus as well as other Vibrio spp. and gram-negative bacteria in aquaculture

PENGARUH GANGGUAN KESEIMBANGAN HORMON SEX PADA WANITA TWRHADAP JARINGAN PERIODONTIUM

X,5

Therapeutic potentials of Excoecaria agallocha against gram-positive and gram-negative fish bacterial pathogens

Background: The present investigation of a mangrove plant, Excoecaria agallocha, which is a popular medicinal substitute for the treatment of microbial ailments, were evaluated for potential antimicrobial activity against pathogenic bacteria Escherichia coli and Streptococcus agalactiae in tilapia, Oreochromis niloticus. Methods: Antibacterial activity was performed using agar diffusion method, disc diffusion method, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiotic susceptibility assays. Experimental fish fed diet containing 0 (control), 5, 25, and 50 mg kg-1 E. agallocha leaf methanol extract for 28 days then challenged individually with E. coli or S. agalactiae and mortalities were recorded over a ten-day post-infection period.  Results: Results indicated that both bacterial species are sensitive to tetracycline, ampicillin, and amoxicillin. E. coli was found to be resistant to neomycin. E. agallocha extract concentration of 50 mg/ml produced a zone of inhibition of 18 mm against E. coli, in contrast to 13 mm against S. agalactiae.  E. agallocha showed bactericidal activity against E. coli and bacteriostatic activity against S. agalactiae. The highest E. agallocha LC50 activity was 83 mg/ml. The highest cumulative mortality was 90.0 ± 10.0% in control as compared to 26.7 ± 11.5% in the group fed with 50 mg kg-1 E. agallocha extract, significant differences (P < 0.05). Conclusion: Hence, E. agallocha showed antibacterial activity against fish pathogens Escherichia coli and Streptococcus agalactiae in tilapia, Oreochromis niloticus; therefore, E. agallocha may be used as an alternative therapeutic agent against fish pathogenic bacteria as an additive to feed at a concentration depend, safe, non-cytotoxic doses

Teknik Budidaya Kerapu Cantang (Ephinephelus Fuscoguttatus-lanceolatus) pada Keramba Jaring Apung di Balai Budidaya Air Payau, Situbondo, Jawa Timur [Culture Techniques Of Cantang Grouper (Epinephelus Fuscoguttatus Lanceolatus) At Floating Net Cages In Brackish Water Aquaculure Development Center, Situbondo East Java]

Pelatihan industri telah dilakukan untuk mempelajari dan memahami teknik budidaya dari Kerapu Cantang (Epiphenelus sp.). Teknik budidaya kerapu Cantang merupakan salah satu faktor yang akan mempengaruhi tingkat pertumbuhannya. Pengambilan sampel ikan dilakukan selama 21 hari di Pusat Pengembangan Budidaya Perikanan Air Payau, Situbondo, Jawa Timur. Hasil penelitian ini menunjukkan bahwa pertumbuhan kerapu Cantang meningkat signifikan sebesar 2,29 gram/hari. Pengelolaan pakan dan kualitas air yang baik dianggap sebagai faktor utama yang berpengaruh pada pertumbuhan Kerapu Cantang selama proses budidaya