Aquaculture is rapidly growing and will soon overtake wild-capture fisheries as our dominant source of seafood (FAO, 2010). Farming of salmon and trout is economically the most important within the EU and is rightly promoted as a healthy source of animal protein. However, ironically the culture of these carnivorous species may aid in the collapse of ocean fisheries, due to the requirement for wild-caught fishmeal in their diet. A current BBSRC Industrial Partnership Award project is investigating methods to improve the sustainability of aquaculture by both reducing the reliance on fishmeal and minimising the output of effluent that can cause eutrophication. This project focuses on a major phenomenon associated with feeding in vertebrates – the “alkaline tide” – the transfer of HCO3– into the blood from the stomach cells after a meal to compensate for acid secretion into the stomach. The alkaline tide is only recently discovered in fish (Cooper and Wilson, 2008) but has a number of important, but poorly understood, whole organism repercussions (e.g. acid-base, ion and osmotic regulation, and respiratory gas transport). These incur energetic costs that raise metabolic demand after a meal and detract from energy invested in growth. This integrative physiology PhD project aims to combine in vivo and in vitro physiology with transcriptomic/proteomic approaches to assess dietary manipulations designed to minimize the alkaline tide, and to test their applicability to improve the efficiency of converting food into growth across a range of fish species (including carnivores, omnivores and herbivores) used in aquaculture globally.
Deadline: 11th January 2013