Digestive physiology of spiny lobsters: implications for formulated diet development

Abstract

The development of cost-effective and nutritionally adequate formulated feeds is a key step for developing sustainable technologies for new aquaculture species. There has been many research effort for over 30 years on feed development for spiny lobsters, but amazingly, poor performance of formulated feeds remains one of the major obstacles to progressing commercial aquaculture of these crustaceans. This is partially due to a lack of information on how spiny lobsters digest and assimilate formulated feeds. The aim of this review is to integrate recent information on the digestive physiology of spiny lobsters to identify areas where further studies are needed for advancing to more physiologically tailored formulated feeds. Increasing the efficiency of mechanical and chemical digestion is imperative for better digestion of formulated feeds. This is likely to be achieved by improving feed format, reducing the particle size of ingredients, using digestible binders, preprocessing or selecting more soluble macronutrients and supplementing feeds with additives such as pH buffers, emulsifying agents and/or exogenous enzymes. Future research needs to adopt a holistic approach for investigating the digestive processes in spiny lobsters by focusing on digestion as well as downstream processes. The protein-sparing effect of lipids and carbohydrates on spiny lobster metabolism is of a particular significance as the spiny lobster metabolism is strongly directed towards the use of protein. This review provides important insights, practical solutions and key research directions to improve both our understanding of spiny lobster digestive physiology and the performance of formulated feeds for spiny lobsters.

Molecular, Biochemical, and Dietary Regulation Features of α-Amylase in a Carnivorous Crustacean, the Spiny Lobster Panulirus argus

“…On the other hand, mechanisms for regulating digestive enzymes are largely unknown in invertebrates [ 76 ]. Research in mollusks [ 77 , 78 ] and insects [ 79 , 80 ] pointed that external factors such as diet have significant effects on the regulation of α-amylase, mostly at the transcription level.…”

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization

“…Despite significant achievements made on the larval propagation of spiny lobsters ( Barnard, Johnston & Phillips, 2011 ; Perera & Simon, 2014 ), a major interest remains on the growout of lobsters based on the capture of wild seed ( Williams, 2007 ; Perera & Simon, 2014 ; Radhakrishnan, 2015 ), especially for fast-growing tropical species (e.g., Panulirus argus , Panulirus ornatus ) ( Jeffs & David, 2003 ; Williams, 2007 ; Nguyen, Long & Hoc, 2009 ). However, the absence of appropriate diets is so far the main impediment to the sustainable expansion of this activity ( Williams, 2007 ); during growout, spiny lobsters are currently fed with trash fish ( Perera & Simon, 2014 ; Radhakrishnan, 2015 ), with downstream negative effects such as environmental pollution, poor feed conversion, appearance of emerging diseases, and overpressure on wild fish stocks ( Perera & Simon, 2014 ; Radhakrishnan, 2015 ). Although the nutritional requirements of some spiny lobsters have been evaluated, growth rates with formulated diets are still low for most species ( Crear et al, 2000 ; Glencross et al, 2001 ; Smith et al, 2003 ; Ward et al, 2003 ; Johnston et al, 2003 ; Smith, Williams & Irvin, 2005 ; Simon & Jeffs, 2008 ).…”

“…It is recognized that problems for feeding spiny lobsters with formulated diets are partially due to gaps in our knowledge on their digestive physiology and metabolism ( Perera & Simon, 2014 ). Different studies in the spiny lobster P. argus digestive physiology have been focused on protein digestion ( Perera et al, 2008a ; Perera et al, 2008b ; Perera et al, 2010a ; Perera et al, 2010b ; Perera et al, 2012a ; Perera et al, 2012b ), while digestion of other nutrients has received less attention.…”

Effects of dietary fish oil replacement with blended vegetable oils on growth, lipid metabolism and antioxidant capacity of subadult swimming crabPortunus trituberculatus

“…Previous studies showed that dietary lipids could affect the activities of lipid metabolism‐related enzymes of aquatic animals (Geay et al, ; Zhao, Long, Wu, Liu, He, et al, ). Lipase (LPS) is an important enzyme for lipid digestion and absorption (Johnston, ; Perera & Simon, ). Our study showed that the activity of LPS in hepatopancreas significantly increased with the increasing dietary fish oil replacement level, and it reached a peak at 750g/kg fish oil replacement, which indicates that partial replacement of fish oil by blended vegetable oils may be beneficial for lipid digestion and absorption of swimming crabs.…”