Effect of Fetal Bovine Serum on the Sperm Quality of Depik (Rasbora tawarensis) after Short-term Cryopreservation

Background: Sperm cells are susceptible to oxidative stress during cryopreservation. Therefore, an antioxidant is necessary to protect them from damages. Fetal bovine serum (FBS) is one of potent antioxidants for fish sperm cryopreservation. Hence, the aims of this study are to examine the effect of FBS on sperm quality after a short period and to determine its optimum concentration on depik (Rasbora tawarensis). Methods: Depik fish were obtained from the Fish hatchery of Lukup Badak, Aceh Tengah District, Indonesia. Sperms collected from the fish were diluted in Ringer extenders containing FBS concentration of 10% (P1), 20% (P2), 30% (P3), 40% (P4), 50% (P5) and 60% (P6), filled into 2 ml cryotubes and equilibrated prior immersed into liquid nitrogen for 15 days. The parameters observed were sperm motility, consistency, pH, fertilization and hatching rates and DNA fragmentation post-thawing. Result: The ANOVA test indicates that the application of FBS in Ringer had a significant effect on sperm motility, fertilization and hatching rates (P less than 0.05). The highest motility (58.33%) was recorded at FBS 60% and significantly different from those at other concentrations. The laddering analysis showed that applying FBS protected the integrity of depik sperms DNA. It is concluded that the optimum concentration of FBS on depik sperm led to a short-term cryopreservation of 60%.

Oviposition activity of Haemagogus leucocelaenus (Diptera: Culicidae) during the rainy and dry seasons, in areas with yellow fever virus circulation in the Atlantic Forest, Rio de Janeiro, Brazil

The present study aims to analyze the effectiveness of ovitraps in the capture of Hg leucocelaenus eggs and evaluate the influence of the dry and rainy seasons on their abundance and hatching rates. The eggs were collected in the Atlantic Forest of State of Rio de Janeiro, Brazil, an area in which the yellow fever virus is known to circulate. We distributed 15 ovitraps in three sampling points, with five ovitraps per point. We distributed 15 ovitraps in three sampling points on trees within a forested area, which were sequentially numbered, monitored, and replaced every two weeks from October 2016 to April 2018. There was a high dominance of Hg. leucocelaenus eggs (98.4%) and a variation in egg hatching rates between the wet and dry seasons. These rates were 1.5 times higher in the rainy season than in the dry season. The rainy season also showed a greater abundance of eggs and higher values of ovitrap positivity and egg density indexes in the installed ovitraps. The abundances of Hg. leucocelaenus eggs were positively correlated with mean monthly temperature and air humidity but not significantly correlated with accumulated precipitation. These results, as well as their implications for the possible use of ovitraps to monitor vector mosquitoes of yellow fever in the study region, are discussed.

Hatching Under Brownification: DOC-Mediated Changes in Physical, but Not Chemical Properties of Water Affect Hatching Patterns of Cladocera Resting Eggs

Dissolved organic carbon (DOC) is often related to the brownification of water in continental aquatic systems and to changes in the physiology of zooplankton organisms. Zooplankton resting eggs are particularly sensitive to changes in light and chemical characteristics of water, but the physical and chemical effects associated to DOC on dormant stages have never been tested before. Herein we tested how DOC affects hatching rates and time to hatching of Cladocera (Diaphanosoma birgei) resting eggs. In order to analyze the chemical (i.e. toxic) and physical (i.e. light attenuation) effects of DOC on hatching patterns, resting eggs were exposed to different concentrations of DOC in an experimental design which isolated chemical from physical effects. We observed higher hatching rates and lower time to hatching at intermediate DOC concentrations. DOC effects on hatching mainly relied on light attenuation, while chemical effects were likely of minor importance. We conclude that DOC may change Cladocera emergence patterns mainly through light attenuation in the water column.

Genomic analysis of Landes goose origin goose hemorrhagic polyomavirus, China

A goose hemorrhagic polyomavirus (GHPV) outbreak occurred in a Goose Farm in Hunan, China, between January and July 2021. Approximately 1,500 breeding goose died, and hatching rates dropped from the previous 85% to about 50% in this outbreak. GHPV HUN-01, isolated from the liver of infected Landes geese, shared a close evolutionary relationship with the Toulouse Goose 2000 and 14234 strain, isolated from geese in France and Hungary. The isolation of GHPV from the livers of dead embryos also demonstrates that the virus can be transmitted vertically. In conclusion, clinical and laboratory diagnostics of the diseased geese in this outbreak were consistent with GHPV being the causative agent. We learned that this is the first time that GHPV has been isolated from geese in mainland China.

Green Anole lizards (Anolis carolinensis) deposit eggs in nests of the Trap Jaw Ant, Odontomachus brunneus

Squamates eggs are rarely found in ant nests, and are largely restricted to the nests of neotropical fungus gardening in the tribe Attini. Ponerine ant nests have not previously been reported as nesting cavities for squamates, including the Green Anole (Anolis carolinensis). The current study reports the association of Green Anole eggs and hatchlings with the subterranean nest chambers of the trap jaw ant, Odontomachus brunneus. Hatching rates suggest that O. brunneus nests may be used communally by multiple females, which partition spatial resources with other recently introduced Anolis species in their native range. This new nesting strategy is placed in the context of know associations between frogs, snakes, legless worm lizards and ants.

PGE2 Supplementation of Oocyte Culture Media Improves the Developmental and Cryotolerance Performance of Bovine Blastocysts Derived From a Serum-Free in vitro Production System, Mirroring the Inner Cell Mass Transcriptome

The culture media used throughout the in vitro production (IVP) of bovine embryos remain complex. The serum added to culture media in order to improve embryo development negatively impacts the cryotolerance of blastocysts. Periconceptional prostaglandin E2 (PGE2) signaling is known to exert prosurvival effects on in vitro-generated blastocysts. The purpose of the present study was to evaluate the effects on developmental and cryotolerance performance of a serum-free (SF) IVP system that included defined oocyte culture media supplemented or not with PGE2, versus serum-containing (SC) IVP. RNA-sequencing analysis was used to examine the gene expression of ICM derived under the different IVP conditions. We assessed the degree of cryotolerance of grade-I blastocysts during a three-day post-thaw culture by measuring survival and hatching rates, counting trophectoderm and inner cell mass (ICM) blastomere numbers. We also determined the proportion of ICM cells expressing octamer-binding transcription factor 4 protein (OCT4/POU5F1). We showed that grade-I blastocyst development rates under SF + PGE2 conditions were similar to those obtained under SC conditions, although the cleavage rate remained significantly lower. SC IVP conditions induced changes to ICM gene expression relative to several metabolic processes, catabolic activities, cell death and apoptosis. These alterations were associated with significantly higher levels of ICM cell death at day 7 post-fertilization, and lower survival and hatching rates after thawing. SF IVP conditions supplemented or not with PGE2 induced changes to ICM gene expression related to DNA replication, metabolism and double-strand break repair processes, and were associated with significantly larger ICM cell populations after thawing. SF + PGE2 IVP induced changes to ICM gene expression related to epigenetic regulation and were associated with a significantly higher proportion of ICM cells expressing OCT4. For the first time, our study thus offers a comprehensive analysis of the ICM transcriptome regulated by IVP culture conditions in terms of the cellular changes revealed during culture for three days after thawing.

Dose Optimization of Ovatide Hormone for Induced Breeding of Freshwater Gang Magur, Hemibagrus Menoda (Hamilton, 1822)

An experiment on induced breeding of gang magur, Hemibagrus menoda (Hamilton, 1822) using Ovatide hormone was carried out at in the Field Laboratory Complex of Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. This study consists of three treatments each with three replications. The objective of the experiment was to find out the effective dose of Ovatide hormone for induced breeding. A total number of 54 brood fish were used for the experiment among which 36 were male and 18 were female. Brood fish were kept in the ratio of 2♂:1♀ for breeding purpose. Female brood fish were injected at the rate of 7, 5, 3 ml Ovatide/kg body weight while the males were injected with 3, 2.5 and 1.5 ml Ovatide/kg body weight respectively in T1, T2, and T3 at the same time. The brood fish were injected with single dose of Ovatide in all treatments. Ovulation rates were 0%, 100%, 63%; fertilization rates were 0%, 97%, and 90%, and hatching rates were 0%, 95% and 76% in treatments T1, T2, and T3 respectively. Fertilized eggs were incubated for 21-22 h in all the treatments. Higher ovulation rate (100 %), fertilization rate (97%), hatching rate (95%) and survival rate (85%) were found in treatment T2. Therefore, the optimum dose of Ovatide hormone for induced breeding of H. menoda is 2.5 and 5 ml Ovatide/kg body weight of male and female brood fish, respectively. Res. Agric., Livest. Fish.8(1): 171-179, April 2021