Reduction Of Gonadosomatic Index Research Articles

Starvation-induced autophagy modulates spermatogenesis and sperm quality in Nile tilapia

Spermatogenesis is a finely regulated process that involves the interaction of several cellular mechanisms to ensure the proper development and maturation of germ cells. This study assessed autophagy contribution and its relation to apoptosis in fish spermatogenesis during starvation. To that end, Nile tilapia males were subjected to 0 (control), 7, 14, 21, and 28 days of starvation to induce autophagy. Testes samples were obtained for analyses of spermatogenesis by histology, electron microscopy, immunohistochemistry, and western blotting. Sperm quality was assessed using a computer-assisted sperm analysis (CASA) system. Data indicated a significant reduction in gonadosomatic index, seminiferous tubule area, and spermatozoa proportion in fish subject to starvation compared to the control group. Immunoblotting revealed a reduction of Bcl2 and Beclin 1 associated with increased Bax and Caspase-3, mainly after 21 and 28 days of starvation. LC3 and P62 indicated reduced autophagic flux in these starvation times. Immunolabeling for autophagic and apoptotic proteins occurred in all development stages of the germ cells, but protein expression varied throughout starvation. Beclin 1 and Cathepsin D decreased while Bax and Caspase-3 increased in spermatocytes, spermatids, and spermatozoa after 21 and 28 days. Autophagic and lysosomal proteins colocalization indicated the fusion of autophagosomes with lysosomes and lysosomal degradation in spermatogenic cells. The CASA system indicated reduced sperm motility and velocity in animals subjected to 21 and 28 days of starvation. Altogether, the data support autophagy acting at different spermatogenesis stages in Nile tilapia, with decreased autophagy and increased apoptosis after 21 and 28 days of starvation, which results in a decrease in the spermatozoa number and sperm quality.

Acaricidal Properties of Bio-Oil Derived From Slow Pyrolysis of Crambe abyssinica Fruit Against the Cattle Tick Rhipicephalus microplus (Acari: Ixodidae).

Slow pyrolysis is a process for the thermochemical conversion of biomasses into bio-oils that may contain a rich chemical composition with biotechnological potential. Bio-oil produced from crambe fruits was investigated as to their acaricidal effect. Slow pyrolysis of crambe fruits was performed in a batch reactor at 400°C and chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The bio-oil collected was used in bioassays with larvae and engorged females of the cattle tick Rhipicephalus microplus. Biological assays were performed using the larval packet test (LPT) and adult immersion test. The GC-MS of crambe fruit bio-oil revealed mainly hydrocarbons such as alkanes and alkenes, phenols, and aldehydes. The bio-oil in the LPT exhibited an LC90 of 14.4%. In addition, crambe bio-oil caused female mortality of 91.1% at a concentration of 15% and a high egg-laying inhibition. After ovary dissection of treated females, a significant reduction in gonadosomatic index was observed, indicating that bio-oil interfered in tick oogenesis. Considering these results, it may be concluded that slow pyrolysis of crambe fruit affords a sustainable and eco-friendly product for the control of cattle tick R. microplus.

Effect of cobalt-60 gamma radiation on reproductive disturbance in freshwater prawn Macrobrachium rosenbergii (De Man, 1879).

The present study was designed to evaluate the effect of acute level of 60Co gamma radiation on fecundity of freshwater prawn Macrobrachium rosenbergii. Prawns were exposed to four different dose levels (3, 30, 300 and 3000 mGy) and their reproductive disturbances i.e Gonadosomatic Index (GSI), Egg Clutch somatic Index (ESI), Egg Counts and Egg hatching rates were calculated. The experimental group showed significant reduction in GSI (0.47 ± 0.01) & ESI (1.22 ± 0.08) after exposure to 60Co gamma radiation. Egg Count (3713 ± 21) and Egg hatching rates (3798 ± 11) were significantly reduced in all irradiated groups. The number of dead larva increased with the increasing level of doses. With the increase in dosage level, the gonad and egg clutch weight were decreased which likely lead to reduced number of eggs. Our results proved that even low level of ionizing radiation (60Co) affects the fecundities of freshwater crustacean M. rosenbergii.

MC-LR Exposure Leads to Subfertility of Female Mice and Induces Oxidative Stress in Granulosa Cells

Health risk of human exposure to microcystin-leucine arginine (MC-LR) has aroused more and more attention over the past few decades. In the present study, MC-LR was orally administered to female mice at 0, 1, 10 and 40 μg/L for three and six months. We found that chronic exposure to MC-LR at environmental levels could stimulate follicle atresia and lead to decreased developmental follicles, accompanied by a reduction of gonadosomatic index (GSI). In line with the irregular gonadal hormone level and estrus cycles, subfertility of female mice was also confirmed by analyzing numbers of litters and pups. The in vitro study suggested that granulosa cells could uptake MC-LR and should be the target of the toxicant. Oxidative stress in granulose cells induced by MC-LR promoted follicle atresia and eventually leads to female subfertility.

Impact of Cypermethrin and Carbofuran on the Ovarian Cycle of the Indian Major Carp, Labeo rohita (Hamilton)

A short term histological study was conducted to determine the impacts of technical grade synthetic pyrethroid insecticide, cypermethrin and carbamate pesticide, carbofuran on different phases of ovarian maturation of freshwater indigenous carp, Labeo rohita. Adult females of L. rohita were exposed to sublethal doses of carbofuran (0.06, 0.15 mg/L) and cypermethrin (0.16 and 0.40 μL/L) for 4 weeks during the pre-spawning (March), spawning (July) and post-spawning (November) phase. In the spawning phase, the carp showed maximum ovarian damage by both the pesticides while the pre-spawning phase was the next impaired stage. Considering all the phases of ovarian maturation, cypermethrin exhibited greater level of impact than carbofuran in both of its doses. Gonado-somatic indices for all these phases were also measured. In the reproductive cycle of fish, reduction in gonado-somatic index occurred by both the pesticides in all of its doses and the order was spawning > pre-spawning > post-spawning. It is concluded that ovarian maturation in Indian carp is affected by both the pesticides.

Biological effects and bioaccumulation of steroidal and phenolic endocrine disrupting chemicals in high-back crucian carp exposed to wastewater treatment plant effluents

Endocrine disrupting chemicals (EDCs) found in wastewater treatment plant (WWTP) effluents have been shown to cause adverse effects, but the uptake of EDCs from effluents (measured in fish muscle) are not known. In this study, the biological effects and bioaccumulation of steroidal and phenolic EDCs were assessed in high-back crucian carp ( Carassius auratus) exposed to WWTP effluents for 141 days. Compared with fish controls caged in Dianchi Lake, a significant reduction in gonadosomatic index (GSI) and increase in hepatosomatic index (HSI) and plasma vitellogenin (VTG) levels were observed in effluent-exposed fish. The concentrations of steroids and phenols in effluent-exposed fish showed time-dependent increase during the exposure. In addition, bioconcentration factors (BCFs) for steroids and phenols were between 17 and 59 on day 141. The results confirm that steroids and phenols bioconcentrate in fish muscle and this accumulation may account for the biological effects associated with exposures to WWTP effluents.

Effects of environmental relevant doses of pollutants from offshore oil production on Atlantic cod ( Gadus morhua)

The release of produced water (PW), a by-product of offshore oil production, has increased in Norwegian waters in recent years. Alkylphenols (AP), a major component of PW, have been shown to have endocrine disrupting effects on several fish species. In the present study, four groups of female Atlantic cod ( Gadus morhua) were orally exposed for 20 weeks to two different concentrations of a mixture of C4–C7 APs, PW or 17β-estradiol. The transcriptional responses in the liver of Atlantic female cod were studied using a custom-made cDNA microarray. The largest transcriptional effects were seen in cod exposed to the lowest dose of APs. Several biological processes such as glycolysis, apoptosis and the general stress response were affected by exposure to APs. In addition, genes coding for the detoxification enzymes CYP1A and sulfotransferase 2 were up-regulated in the low exposure group. Significant reduction in gonadosomatic index (GSI) and the concentration of plasma vitellogenin were seen in both AP and 17β-estradiol exposed cod. Exposure to PW had little effect on GSI and the regulation of stress responsive genes. The findings indicate that chronic exposure to low levels of APs may cause a stress response and delayed maturation in female cod.

Effects of ethynylestradiol on the reproductive physiology in zebrafish (Danio rerio): Time dependency and reversibility

Environmental pollution with natural or synthetic estrogens may pose a serious threat to reproduction of wildlife species. This study describes the effects of 17-alpha-ethynylestradiol (EE2) on fish reproductive organs in a laboratory model. Adult zebrafish were semistatically exposed to nominal concentrations of 0, 10, and 25 ng/L EE2 for 24 d and then transferred to EE2-free medium. Gonadosomatic index (GSI), plasma vitellogenin concentration (VTG), and histology of the gonads (control and 10 ng/L only) were examined as a function of time. It was found that EE2 has an adverse impact on both male and female reproductive organs. Notably in females, gonadal changes were observed through histological evaluation after 3 d of exposure to 10 ng/L EE2. and this was followed by a reduction of GSI at day 6 of exposure. In males, a reduction of GSI and altered testis histology was found after 24 d of exposure to 10 ng/L. The observed effects on the ovary after EE2 exposure, combined with complete recovery after 24 d, is considered to be triggered by feedback at the level of the pituitary. In both males and females, VTG was induced in response to EE2 and normalized during the recovery period. The observed correlation between VTG and ovarian somatic index (OSI) demonstrates that excessive VTG induction may be predictive for adverse effects of EE2 on ovarian function in female zebrafish. These results indicate that long-term stimulation by synthetic estrogens such as EE2 might impair reproductive function in zebrafish in a reversible manner.