Host Species and Environment Shape the Gut Microbiota of Cohabiting Marine Bivalves.

Pacific oysters (Crassostrea gigas) and Mediterranean mussels (Mytilus galloprovincialis) are commercially important marine bivalves that frequently coexist and have overlapping feeding ecologies. Like other invertebrates, their gut microbiota is thought to play an important role in supporting their health and nutrition. Yet, little is known regarding the role of the host and environment in driving these communities.

Methylmercury bioaccumulation in water flea Daphnia carinata by AIEgen.

Mercury ion (Hg) is a toxic heavy metal ion and Hg is convertible to methylmercury (MeHg) by many aquatic microorganisms, leading to bioaccumulation and biomagnification in aquatic organisms, which can interfere with brain development and function in humans. This study employs a newly developed AIEgen (Aggregation-induced emission fluorogen) to quantify and visualise the process of MeHg bioaccumulation in vivo on the species of water flea Daphnia carinata. Two approaches to MeHg absorption were taken, either by direct incubation in a MeHg solution or by indirect consumption of algae contaminated with MeHg.

Comparison of partial replacement of fishmeal with soybean meal and EnzoMeal on growth performance of Asian seabass Lates calcarifer.

This study explored the impact of fishmeal replacement by commercial soybean meal (SM) and EnzoMeal (EZM) on Asian seabass Lates calcarifer growth performance using six diets. The six diets comprised two sources of plant proteins with three levels each, including 300 g kg soybean meal (SM30), 300 g kg EnzoMeal (EZM30), 400 g kg soybean meal (SM40), 400 g kg EnzoMeal (EZM40), 500 g kg soybean meal (SM50), and 500 g kg EnzoMeal (EZM50). The soybean level was shown to significantly affect the final fish weight, weight gain, specific growth rate (SGR), survival, feed intake, feed conversion ratio (FCR), and apparent digestibility coefficient (ADC).

Improvement of post-thaw sperm survivals using liquid nitrogen vapor in a spermcasting oyster Ostrea angasi.

Low survival of cryopreserved sperm impedes the application of cryopreservation technique in spermcasting oyster species. This study developed a simple method of liquid nitrogen vapor freezing to improve post-thaw sperm survival in the spermcasting oyster Ostrea angasi. The results indicate that the permeable cryoprotectants, dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG) were non-toxic to sperm up to 20% concentration and 90 min exposure whereas methanol at 10% or higher was toxic to sperm for any exposure over 30 min.

Sperm cryopreservation in the spermcasting Australian flat oyster Ostrea angasi by a programmable freezing method.

Cryopreservation offers long-term storage of gametes without constraint from seasonal gamete maturation, provides opportunities to improve the efficiency of breeding and genetic programs, and protects endangered species from extinction due to epidemic diseases and natural disasters. In this study, a protocol for cryopreserving sperm of the spermcasting Australian flat oyster Ostrea angasi was developed by optimizing key factors influencing the quality of cryopreserved sperm. Dimethyl sulfoxide (DMSO) was non-toxic to sperm within the concentration and duration assessed in the toxicity experiment whereas 10% methanol or a higher concentration was toxic to sperm from the exposure duration of 30 min onwards.

Spermatozeugmata structure and dissociation of the Australian flat oyster Ostera angasi: Implications for reproductive strategy.

Variation in reproductive strategy is one of the key factors contributing to recruitment success of molluscs in different habitats. Spermcasting is a unique mode in mollusc reproduction where males produce spermatozeugmata, a radially arrayed sperm cluster wrapped by gelatinous membrane. In this study, spermatozeugmata structure and their dissociation in the Australian flat oyster Ostrea angasi were investigated to elucidate the reproductive strategy in spermcasting molluscs.

Sperm cryopreservation of the Indian major carp, Labeo calbasu: effects of cryoprotectants, cooling rates and thawing rates on egg fertilization.

A sperm cryopreservation protocol for the Indian major carp, Labeo calbasu, was developed for long-term preservation and artificial fertilization. Milt collected from mature male fish were placed in Alsever's solution (296mOsmolkg(-1)) to immobilize the sperm. Cryoprotectant toxicity was evaluated by motility assessment with dimethyl sulfoxide (DMSO) and methanol at 5, 10 and 15% concentrations.