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


Khan U. K.

JOURNAL OF FISH BIOLOGY, vol.100, no.6, pp.1388-1398, 2022 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 100 Issue: 6
  • Publication Date: 2022
  • Doi Number: 10.1111/jfb.15049
  • Journal Name: JOURNAL OF FISH BIOLOGY
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Animal Behavior Abstracts, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, CAB Abstracts, EMBASE, MEDLINE, Veterinary Science Database
  • Page Numbers: pp.1388-1398
  • Keywords: aquaculture, exponential function, feeding frequency, gastric evacuation time, Salmonidae, COD GADUS-MORHUA, SQUARE-ROOT MODEL, PREDATORY GADOIDS, FOOD-CONSUMPTION, STOMACH CONTENTS, ATLANTIC SALMON, NORTH-SEA, RATES, PREY, FREQUENCY

Abstract

This study examined the rate and course of gastric evacuation (GE) in rainbow trout Oncorhynchus mykiss in relation to meal size, body size and temperature. The GE experiments were performed on small (mean +/- 95% C.I., 17.7 +/- 0.5 cm total length), medium (22. 9 +/- 0.2 cm) and large (28.3 +/- 0.3 cm) rainbow trout fed meals of different sizes using commercial food pellets at water temperatures T ranging from 7.8 degrees C to 19.2 degrees C. Estimating the shape parameter of a general power function suggested that the square root function adequately described the GE in rainbow trout independently of meal size. The effects of total body length L and weight W on gastric evacuation rate (GER) were described by simple power functions. The square root function was further expanded by a temperature function with temperature optimum to describe the effect of temperature. The expanded square root function revealed a considerable effect of body size and temperature on the GER of rainbow trout. The GER increased exponentially with rising temperature, reached an optimum at c. 18.5 degrees C and then declined abruptly to zero at c. 21 degrees C. The GER of rainbow trout could thus be described by dSt dt 1/4 0:00152L0:75e0:08 T 1 e1:18oT 20: 9THORN ffiffiffiffi Stp (g h(-1)) or dSt dt 1/4 0:00440W0:26e0:08 T 1 e0:97oT21:1THORNffiffiffiffi Stp (g (h-1)), where St is the current stomach content mass (g), and at post-prandial time t (h). These functions should prove useful to calculate total GE time as well as stomach fullness at different post-prandial times and therefore provide valuable information to develop optimal feeding strategies for farming of rainbow trout.