David Francis

David Francis
Deakin University · School of Life and Environmental Sciences

BSc (Hons), PhD

About

122
Publications
30,367
Reads
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2,692
Citations
Additional affiliations
February 2015 - present
Deakin University
Position
  • Professor (Associate)
January 2011 - February 2015
Australian Institute of Marine Science
Position
  • Researcher
June 2006 - January 2011
Deakin University
Position
  • Lecturer

Publications

Publications (122)
Article
Full-text available
The production of farmed Atlantic salmon (Salmo salar) is currently linked to finite marine resources, particularly fish oil (FO) and fish meal (FM). Understanding this relationship in a quantitative manner is imperative if this critical balance is to be maintained within sustainable limits as the industry grows. Here we project the potential produ...
Article
Full-text available
Seaweed cultivation is gaining interest world-wide for both food and non-food applications. Global seaweed aquaculture production currently exceeds 32 Mt WW per annum but is dominated (86% of total) by Asian countries. To meet future demand for seaweed products, regions beyond Asia with aquaculture production potential are being explored. The goal...
Article
Macrocystis pyrifera (Linnaeus) C. Agardh (Ochrophyta), also known as giant kelp, is a key species in coastal ecosystems of temperate regions worldwide providing important habitats and food for a range of species. M. pyrifera also has the potential for cultivation for commercial application (e.g. food, food additives and feed). This study compared...
Article
The gut transit rate of ingested feed in fish affects the utilization of dietary nutrients; however, the influence of water temperature, remains underexplored in Atlantic salmon (Salmo salar). The present study quantified the gut transit rate of four distinct regions of the gastrointestinal tract (stomach, pyloric caeca, small and large intestine)...
Article
Full-text available
The effects of tuna viscera hydrolysate (TVH) on juvenile pompano Trachinotus blochii, growth performance, nutritional response, intestinal and liver health, and resistance to Streptococcus iniae were investigated in this study. Five isonitrogenous and isocaloric diets (protein 46.0%, lipid 10.0%) were formulated in which TVH was added to replace f...
Article
Global demand for seaweed is increasing alongside the interest for sustainable aquaculture, stimulating industry investment in the production of seaweeds, particularly through integrated multitrophic aquaculture systems. We report the first results of the nutritional value (proximate composition, fatty acids, and dietary minerals) and heavy metal p...
Article
Full-text available
The flavour of aquatic animal products is distinct from terrestrial foods, facilitating a competitive marketing advantage. However, the flavour of aquatic animals can also be highly variable. Importantly, differences are reported in the flavour of animals from aquaculture and wild‐capture systems. These differences can erode consumer acceptance of...
Article
This study was conducted to investigate the combined effects of probiotic yeast, Saccharomyces cerevisiae, and lactic acid bacteria, Lactobacillus casei on the growth performance, biochemical response, cytokine gene expression, gut histomorphology and microbial composition of juvenile barramundi, Lates calcarifer. Barramundi juveniles with an initi...
Chapter
After a general overview of lipid biochemistry, this chapter is structured into three main sections. The first one follows the journey of lipids from feed intake, to digestion and absorption, the metabolic fates of lipids, including catabolic and anabolic processes, and interactions with the microbiome. The second section expands on some specific l...
Article
Full-text available
Hyper-spectral and multi-spectral light sensors were used to examine the effects of elevated suspended sediment concentration (SSC) on the quantity and quality (spectral changes) of underwater downwelling irradiance in the turbid-zone coral reef communities of the inner, central Great Barrier Reef (GBR). Under elevated SSCs the shorter blue wavelen...
Article
Ovary is an important edible component of female crabs in many countries, and ovarian fullness (maturity) had become an important quality indicator used for crab marketing. Adult females Portunus trituberculatus are typically divided into four grades (Grade I - Ⅳ) based on ovarian fullness in the carapace during the marketing. This study investigat...
Article
A 60‐day feeding trial was carried out to investigate the effects of fish protein hydrolysate (FPH) in high lupin meal (LM) diets on growth, health and immunity of barramundi. Fish were fed a fishmeal‐based control diet (FM) and three test diets to replace 75% fishmeal protein in the control diet by lupin meal alone (LM), lupin meal with FPH (LM+FP...
Article
In the effort to increase the commercial value of urchin gonads produced via roe enhancement aquaculture, a variety of formulated feeds have been tested to increase gonad production and improve colour and taste. The addition of dried algal supplements to formulated feeds can further enhance gonad quality, but the level of improvement is highly vari...
Article
The reduction in benthic light from natural sediment resuspension events, dredging activities and clouds was quantified over multiple time periods (days to weeks) from a 3-year in-situ field study in the inshore turbid-zone coral communities of the Great Barrier Reef. The results were then used to examine the tolerance levels of three coral species...
Article
Aquafeed manufacturers are increasingly interested in ensuring consistently high-quality products, while relying heavily on poultry offal meal (POM), which is inevitably variable. This study examined the chemical composition of 22 different commercially and experimentally produced POM to determine which chemical variables best predict in vivo prote...
Article
Sea urchin gonads (roe) are a prized global sea food commodity, with growing demand driving the need for urchin roe enhancement aquaculture. Effective roe enhancement of urchins using formulated feeds require species‐specific optimization and an understanding of the interactions between key dietary components (e.g. protein, lipid, carbohydrate, ene...
Article
Seasonal changes in water temperature affect the utilization of dietary fatty acids in Atlantic salmon (Salmo salar L.). Furthermore, fatty acid profiles of terrestrial oils dictate their suitability in terms of provision of metabolic energy and final product quality. An on‐farm, growth trial of Atlantic salmon was conducted in Tasmania, Australia...
Article
Full-text available
To understand how environmental conditions and reproductive events affect coral energetic status, seasonal variations in lipid and fatty acid profiles of the common scleractinian coral, Acropora millepora, were studied from pre-spawning in November 2009 until post-spawning in November 2010 at Halfway Island (in the Keppel Island Group, Southern Gre...
Article
Full-text available
Abstract Corals are dependent upon lipids as energy reserves to mount a metabolic response to biotic and abiotic challenges. This study profiled lipids, fatty acids, and microbial communities of healthy and white syndrome (WS) diseased colonies of Acropora hyacinthus sampled from reefs in Western Australia, the Great Barrier Reef, and Palmyra Atoll...
Article
Fish are the main source of long-chain polyunsaturated fatty acids (LC-PUFA, > C18) for human consumption. In general, it has been widely observed that the fatty acid (FA) profiles of farmed fish are reflective of the diet. However, the degree of tissue FA “distortion” based on incorporation of different dietary FA into fish tissues varies greatly...
Article
Choline plays a crucial role in lipid metabolism for fish, and its deficiency in aquafeed has been linked to compromised health and growth performance. A 56-d experiment was conducted to examine the effects of dietary choline on lipid composition, histology, and plasma biochemistry of yellowtail kingfish (Seriola lalandi; YTK; 156 g initial body we...
Article
The aim of this study was to assess the effects of fishmeal replacement using a mixed blend of fermented soybean, chicken, blood, pork and shrimp meal in the diets for subadult Chinese mitten crab (Eriocheir sinensis). Five diets were formulated by replacing 0%, 17%, 33%, 50% and 67% of fishmeal with a protein mixture (Diet 1–Diet 5). The subadult...
Article
This study quantified the effects of temperature on reproduction and maternal provisioning of the ectoparasite, Neobenedenia girellae (Platyhelminthes: Monogenea), a species known to cause detrimental impacts to aquaculture fishes in tropical and subtropical environments worldwide. At 20 and 25 °C, parasites exhibited relatively slower production o...
Article
High mortality during larval rearing is a persistent bottleneck in finfish aquaculture and is often caused by inadequate nutrition. Nutritional deficiencies in live feeds are usually overcome by enrichment with commercial lipid emulsions; however, enriching live feeds using microalgae may be more effective. This study investigated the efficacy of t...
Article
Elucidating the specific effects of diet on the fatty acid composition in Atlantic salmon (Salmo salar), particularly health beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC PUFA), remains an area of intense commercial interest given the increasing market restrictions placed on the supply of fishmeal and fish oil. The present study...
Article
The Murray cod (Maccullochella peelii peelii), an iconic Australian freshwater fish, is subject to a small but growing aquaculture sector in Australia. Optimal larviculture techniques for this species have yet to be established, particularly with regard to the nutritional quality of starter diets. As such, optimisation of current Murray cod hatcher...
Article
Developing an optimal heterotrophic feeding regime has the potential to improve the growth and overall health of captive corals. This study evaluated the efficacy of seven unique feeding strategies for Acropora loripes, Acropora millepora, and Acropora tenuis nubbins: a novel, micro-bound diet (ATF), a novel, dissolved diet rich in long-chain polyu...
Article
Tamoxifen (TAM) is an antiestrogenic agent and can enter the aquatic environment in wastewater. It has been reported that TAM can induce hepatic steatosis in vertebrates, however, the effects of TAM exposure on lipid metabolism of hepatopancreas in crustaceans remains unclear. In this study, four TAM concentrations (0, 6.7, 13.4 and 20 μg g-1 crab...
Article
Full-text available
Interest in sea urchin roe enhancement aquaculture is growing due to an increased global demand for high-quality roe that is suitable for export to international markets. Yet, fine-tuning of efficient collection methods and improved growing techniques are still key bottlenecks to industry success. Urchins suitable for roe enhancement are generally...
Article
Full-text available
A more efficient utilisation of marine derived sources of dietary omega-3 long-chain polyunsaturated fatty acids (n-3 LC PUFA) in cultured Atlantic salmon (Salmo salar L.) could be enhanced by nutritional strategies that maximise endogenous n-3 LC PUFA synthesis. The objective of the present study was to quantify the extent of n-3 LC PUFA biosynthe...
Article
Full-text available
Fatty acids (FA) play a vital role in coral physiology, metabolism and stress resistance. Optimal health requires a balance of fatty acids, and more specifically essential polyunsaturated fatty acids (PUFA), for efficient biochemical and physiological functioning. Therefore, it is necessary to fully assess and evaluate the viability of FA as biomar...
Article
Full-text available
Developing an optimal heterotrophic feeding regime has the potential to improve captive coral growth and health. This study evaluated the efficacy of three exogenous diets: Artemia nauplii (ART), a commercially available coral diet (Reef Roids) (RR), and a novel, micro-bound diet (ATF), against a comparatively natural, unfiltered seawater treatment...
Article
A common strategy for aquafeed manufacturers has been the utilisation of relatively large amounts of terrestrial, both animal and plant, oil sources to produce diets with a high energy content. The provision of high fat diets is aimed at promoting the utilisation of energy from lipid, thus increasing the amount of dietary protein used for tissue sy...
Article
Rendered terrestrial animal by-product meals (ABPM) are commonly used in aquafeeds for fish and shrimp. However, the nutrient composition and digestibility of these products is often variable due to differing processing conditions. As such, the aquafeed industry could benefit from technologies that rapidly assess the nutritional quality of ABPM pri...
Article
There is a growing trend of ‘replacing’ long-chain omega-3 polyunsaturated fatty acid (n-3 LC PUFA) rich oils with C18 shorter-chain omega-3 polyunsaturated fatty acid rich oils in Atlantic salmon aquafeed formulations. n-3 LC PUFA, including 20:5n-3 and 22:6n-3, play contrasting physiological roles and are metabolised differently in comparison to...
Article
Full-text available
Overgrazing by the overabundant native purple urchin Heliocidaris erythrogramma has caused kelp-dominated reefs to shift to urchin barrens throughout southeastern Australia. These areas are characterised by low kelp abundance, low biodiversity and high urchin densities. As purple urchin gonads are a delicacy in many countries, commercial harvest fr...
Data
Supplementary Materials for Genes for de novo biosynthesis of omega-3 polyunsaturated fatty acids are widespread in animals fig. S1. Complete view of the phylogenetic tree presented in Fig. 1A, with major metazoan taxonomic clades colored as in Fig. 1. fig. S2. Summary tree (cladogram) showing relationships between major well- supported clades to...
Article
Full-text available
Marine ecosystems are responsible for virtually all production of omega-3 (ω3) long-chain polyunsaturated fatty acids (PUFA), which are essential nutrients for vertebrates. Current consensus is that marine microbes account for this production, given their possession of key enzymes including methyl-end (or “ωx”) desaturases. ωx desaturases have also...
Article
Full-text available
Ocean warming (OW) and ocean acidification (OA) are threatening coral reef ecosystems, with a bleak future forecast for reef-building corals, which are already experiencing global declines in abundance. In contrast, many coral reef sponge species are able to tolerate climate change conditions projected for 2100. To increase our understanding of the...
Article
Full-text available
Scleractinian corals are colonial organisms comprising multiple physiologically integrated polyps and branches. Colonialism in corals is highly beneficial, and allows a single colony to undergo several life processes at once through physiological integration and compartmentalised functioning. Elucidating differences in the biochemical composition o...
Article
A considerable body of literature exists concerning the use of marine-derived raw materials in aquaculture feed formulations and the resulting modifications of the health promoting qualities of farmed fish. However, these investigations and reports are fundamentally limited to fatty acids and little is known regarding the other nutritional characte...
Article
Full-text available
Heterotrophic feeding in newly-settled coral planulae can potentially improve survivorship and accelerate early development in some species; however, an optimal diet to facilitate this does not currently exist. This study evaluated the efficacy of three heterotrophic feeding regimes (enriched rotifers, unfiltered seawater, and a novel, particulate...
Data
Total lipid concentration of planktonic larvae for each Acropora species (mg g AFDW-1). (DOCX)
Data
Effect of different feeding regimes on the survival of Acropora recruits (% survivors). (DOCX)
Data
Effect of different feeding regimes on the surface area gain of Acropora recruits (% gain). (DOCX)
Data
Effect of different feeding regimes on the total lipid and ash composition of Acropora recruits after 93 days. (DOCX)
Data
Effect of different feeding regimes on the fatty acid composition of Acropora loripes recruits after 93 days (mg g lipid-1 and % lipid). (DOCX)
Data
Effect of different feeding regimes on the fatty acid composition of Acropora millepora recruits after 93 days (mg g lipid-1 and % lipid). (DOCX)
Data
Effect of different feeding regimes on the proportion of fused Acropora recruits (% fused). (DOCX)
Data
Fatty acid composition of planktonic larvae for each Acropora species (mg g lipid-1 and % lipid). (DOCX)
Data
Effect of different feeding regimes on the fatty acid composition of Acropora tenuis recruits after 93 days (mg g lipid-1 and % lipid). (DOCX)
Data
Lipid class composition of planktonic larvae for each Acropora species (mg g lipid-1). (DOCX)
Data
Effect of different feeding regimes on the lipid class composition of Acropora recruits after 93 days (mg g lipid-1). (DOCX)
Data
Water quality analyses of CTL and RAW seawater. (DOCX)
Data
Effect of different feeding regimes on the fatty acid composition of Acropora hyacinthus recruits after 93 days (mg g lipid-1 and % lipid). (DOCX)
Article
Full-text available
Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral’s condition. However, discrepanci...
Data
Raw data, proximate, lipid class, and fatty acid results
Data
Supplementary Tables 1 and 2 Table S1 - Lipid class composition of intact samples of four scleractinian species prepared with crushing method. Table S2 - Major fatty acid class composition of intact samples of four scleractinian species prepared with crushing method.
Article
This study explores how plasticity in biochemical attributes, used as indicators of health and condition, enables the coral Acropora tenuis to respond to differing water quality regimes in inshore regions of the Great Barrier Reef. Health attributes were monitored along a strong and weak water quality gradient, each with three reefs at increasing d...
Article
Full-text available
Outbreaks of the crown-of-thorns seastar (CoTS) represent a major cause of coral loss on the Great Barrier Reef. Outbreaks can be explained by enhanced larval survival supported by higher phytoplankton availability after flood events, yet little is known about CoTS larvae feeding behaviour, in particular their potential for selective feeding. Here,...
Article
Information on the nutritional requirements and preferred diets of sea cucumber juveniles is extremely limited and this has hindered development of hatchery culture methods. This study assessed ingestion, cell wall digestion and relative nutritional values of two live micro-algae (Isochrysis aff. galbana (TISO) and Chaetoceros muelleri) and six con...