Parameterizing an expanded square root model to account for the effects of temperature, meal size, and body size on gastric evacuation rate in farmed brown trout

Abstract

Aquaculture is one of the most promising food-producing sectors with great potential as a productive contributor to food security helping to meet the global demand for fish (Msangi et al., 2013).Recent estimations suggest that fisheries-based aquaculture provided 80 million metric tons of food in 2018 (FAO, 2020). It is hoped that aquaculture will help mitigate the pressures put on wild fish stocks by replacing wild fish consumption, as wild fishery outputs have stagnated primarily due to overfishing and climate changes

Temperature, meal size and body size effects on the gastric evacuation of rainbow trout: modelling optimum and upper thermal limits

“…In agreement with several recent studies on GE of various wild and farmed fish species (Andersen, 2001;Andersen et al, 2016;Khan et al, 2016;Khan & Seyhan, 2021), this study found that the course of GE in rainbow trout can be adequately represented by the square root function independently of meal size. This function gives a better fit to the GE data of various wild fish species, such as saithe Pollachius virens, pikeperch Stizostedion lucioperca, whiting Merlangius merlangus and cod Gadus morhua (Andersen, 2001;Andersen et al, 2016;Koed, 2001;Temming & Herrmann, 2003), and farmed fish species such as brook trout Salvelinus fontinalis, Russian sturgeon, Acipenser gueldenstaedtii and farmed brown trout (Khan et al, 2016;Khan & Seyhan, 2021;Mazlum & Alabdullah, 2019). Likewise, several former studies also suggest using the square root function for a better fit to the GE data of various fish (Jobling, 1981;Jobling, 1986;Talbot et al, 1984).…”

“…(2016), and the obtained information was then used to design the experimental meal sizes (Table 1). Like it was the case for Khan and Seyhan (2019, 2021), the GER experiments were conducted at ambient water temperatures during different times of the year to estimate the temperature effect on GER of rainbow trout.…”

“…Several studies have been conducted to parametrise the influence of body size, meal size, temperature and feed properties ( e.g ., dietary energy density, disintegration stability) on GER of various wild and farmed fish species (Andersen, 1999; Bogevik et al ., 2021; Jobling et al ., 1977; Khan et al ., 2016). A parameterised GER model should describe accurately the stomach fullness at different post‐prandial times to provide the essential information for developing appropriate feeding strategies (Grove et al ., 1978; Khan & Seyhan, 2019, 2021; Riche et al ., 2004).…”

“…In addition, Hayward and Weiland (1998) reported no effects of body size on the GER of rainbow trout using this function. Nonetheless, several studies have found considerable effects of body size on GER of both wild and farmed fish species (Andersen, 1998; dos Santos & Jobling, 1995; Jones, 1974; Khan et al ., 2016; Khan & Seyhan, 2021). Moreover, the GER has an optimum temperature as well as an upper thermal limit, which is well documented for various fish species such as Atlantic cod Gadus morhua , Atlantic herring Clupea harengus , European sprat Sprattus sprattus and brook trout Salvelinus fontinalis (Bernreuther et al ., 2009; Khan & Seyhan, 2019; Temming, 1995; Tyler, 1970).…”

Gastric evacuation in European seabass Dicentrarchus labrax (Linnaeus, 1758), forced-fed on commercial pellets

“…Contrarily, several studies have shown that the square root function is the most appropriate model for describing the pattern of food evacuation from the stomach in both farmed and wild fish, independently of meal size. This has been observed in several fish species including pikeperch Stizostedion lucioperca (Koed, 2001), brook trout Salvelinus fontinalis (Khan et al, 2016;Seyhan et al, 2020), brown trout Salmo trutta (Khan and Seyhan, 2021) and rainbow trout Oncorhynchus mykiss (Khan, 2022). Furthermore, Andersen and Beyer (2005) have provided a mechanistic approach to back up the square root function through a geometric abstraction of the stomach contents together with some underlying assumptions to provide a mechanistic so-called cylinder model that can predict evacuation of the contents irrespectively of the composition of the contents and the prehistory of the food intake.…”