Protein and energy nutrition of marine gadoids, Atlantic cod (Gadus morhua L.) and haddock (Melanogrammus aeglefinus L.)

• Main Author: Tibbetts, S.
• Other Authors: Lall, S.P., Verreth, Johan, Schrama, Johan
• Format: Doctoral or Postdoctoral Thesis
• Language: Dutch
• Published: 2012
• Subjects: animal nutrition; aquaculture; cod; compound feeds; dietary protein; digestibility; energy; fish culture; fish feeding; haddock; ingredients; marine fishes; nutrient requirements; aquacultuur; diervoeding; energie; ingrediënten; kabeljauw; mengvoer; schelvis; verteerbaarheid; visteelt; visvoeding; voedingseiwit; voedingsstoffenbehoeften; zeevissen; atlantic cod; Gadus morhua; North Atlantic
• Online Access: https://research.wur.nl/en/publications/protein-and-energy-nutrition-of-marine-gadoids-atlantic-cod-gadus

Primary goals of this thesis were to: 1) examine the in vivo digestion of macronutrients from conventional or alternative feed ingredients used in practical diets of juvenile gadoids (Atlantic cod and haddock), 2) document growth potential of fish at the juvenile grower phase given varying levels of dietary protein and energy and 3) assess the potential of in vitro pH-Stat methods for rapid screening protein quality of feed ingredients, specifically for gadoids. All primary research questions were linked to and built upon one another with the goal of gaining a better understanding of protein and energy utilization of juvenile grower phase gadoids. Studies showed that cod and haddock have a high capacity to utilize a wide range of dietary feed ingredients, such as fish meals, zooplankton meal, soybean products (meal, concentrate and isolate) and wheat gluten meal. New dietary formulations for gadoids may also utilize pulse meals, corn gluten meal, canola protein concentrate and crab meal. Digestibility data in this thesis is currently the only research that examined both in vivo and in vitro macronutrient digestibility of a large number and wide range of individual ingredients, specifically for gadoids. This is essential to gain new knowledge on protein and energy utilization as well as for least-cost ration formulations and effective substitution of ingredients into new formulations. Data has demonstrated a dietary digestible protein/digestible energy (DP/DE)ratio of 30 g DP/MJ DE is required for gadoids during the juvenile phase (<100 g) to ensure maximum somatic tissue growth, high digestibility, maximum nitrogen and energy retention efficiency and minimal excessive liver growth. Preliminary nutrient requirement studies together with an applied nutritional approach has identified that feeds for juveniles farmed in the Western North Atlantic should contain 50-55% crude protein, <12% fat and <17% carbohydrate. Data in this thesis is currently the first aimed at development and application of an in vitro ...