Microbiology and immunology of fish larvae

Abstract

For most marine aquaculture species, one of the main bottlenecks is the stable production of high quality juveniles. The high and unpredictable mortality in the first weeks after hatching of marine fish larvae remains a challenging problem that needs to be solved. The severity of the problem differs between species, but cannot be considered adequately solved for any species. Both scientific evidence and experience in hatcheries for a variety of fish, shrimp and shellfish species are accumulating as support for the hypothesis that detrimental fish–microbe interactions are the cause of these problems. Host–microbe interactions in reared fish are still poorly understood, except for a few pathogens, and empirical data of the quality required to test this hypothesis, are lacking. This article provides an overview on the current knowledge of the microbial environment of fish larvae, including methodological aspects to characterize the microbial community (both using culture‐dependent and culture‐independent methods). Further, the current knowledge of the immunology of fish larvae is reviewed, including recent advances in the understanding of toll‐like receptors, inflammatory cytokines, mast cells and piscidins, and the ontogeny of the adaptive immune system. Finally, we provide an overview of the state of the art with respect to steering of microbial communities associated with fish larvae – both steering of community composition and of its activity (e.g. by quorum sensing interference).

Dietary supplementation of probiotics improves survival and growth of Rohu (Labeo rohita Ham.) hatchlings and fry in outdoor tanks

“…In addition to feed quality, bacterial infection causes mass mortality (Rigos and Troisi, 2005;Salah et al, 2008;Vadstein et al, 2012). Poor growth, malformation, sudden decrease in survival, and lack of reproductive capacity are other important causes for unavailability of quality seedlings (Mohapatra et al, 2012;Vadstein et al, 2012). Although application of antibiotics and chemotherapeutics is quite effective, drug resistance and residual effects of these chemical/dugs are of major public health concerns.…”

“…Several efforts have been made to develop artificial feed including microencapsulated diet for better rearing of fish larvae (Ghosh et al, 2004). In addition to feed quality, bacterial infection causes mass mortality (Rigos and Troisi, 2005;Salah et al, 2008;Vadstein et al, 2012). Poor growth, malformation, sudden decrease in survival, and lack of reproductive capacity are other important causes for unavailability of quality seedlings (Mohapatra et al, 2012;Vadstein et al, 2012).…”

Germ-free sea bass Dicentrarchus labrax larval model: a valuable tool in the study of host-microbe interactions

“…With capture fisheries becoming increasingly unsustainable due to overfishing, aquaculture is projected to overtake the former in supplying the world's marine protein re quirements in the near future (FAO 2014). However, disease outbreaks impede the sustainable development of global aquaculture (Vadstein et al 2013). Although treatment with antibiotics has been the main strategy for controlling infectious diseases, there is increasing acknowledgment of its limitations in terms of potential toxicity, the engenderment of resistance and residues, as well as environmental impairment (Alderman & Hastings 1998, Jones et al 2004, Cabello 2006, Sapkota et al 2008.…”

Implications of Ecological Niche Differentiation in Marine Bacteria for Microbial Management in Aquaculture to Prevent Bacterial Disease

“…However, the further sustainable expansion of the sector is currently hampered by a number of factors, amongst which diseases are playing a prominent role, especially in the early life stages of the animals (i.e., larviculture [2]). A major group of causative agents are bacterial pathogens, such as Vibrio spp.…”