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Effect of temperature and varying level of carbohydrate and lipid on growth, feed efficiency and nutrient digestibility of brook trout, Salvelinus fontinalis (Mitchill, 1814)

journal contribution
posted on 2023-05-18, 03:29 authored by Md AminMd Amin, Robin Katersky BarnesRobin Katersky Barnes, Louise AdamsLouise Adams
Temperature is the most important environmental factor determining the growth rate offish. Increasing summer temperatures in salmonid growing regions worldwide are presenting new challenges for effective nutrient delivery, particularly as feeds increasingly replace fish oil with cheaper and available energy sources. The effect of temperature and non-protein energy sources on growth performance, nutrient utilisation and digestibility of brook trout, Salvelinus fontinalis was evaluated at temperatures reflective of optimum,15 Celsius degree, and elevated summer conditions, 19 Celsius degree. The experiment was a 2 x 4 factorial design with two temperatures (15 Celsius degree and 19 Celsius degree) and four iso-nitrogenous (protein: 440 g/kg) and isoenergetic (22 MJ/kg) diets. Diets were formulated with increasing carbohydrate level(180-260 g/kg) balanced by decreasing lipid level (170-130 g/kg). A 12-week study was conducted using triplicate group of brook trout with initial weight 48.0 +- 3.46 g at each temperature. Fish were fed 2% body weight ration daily. Growth rate was higher and feed utilisation was more efficient at 15 Celsius degree than 19 Celsius degree (P = 0.00). Reduced fish oil inclusion and increased gelatinised carbohydrate had no effect on growth and feed utilisation at both temperatures. The apparent digestibility coefficients of nutrient and energy were significantly higher at 15 Celsius degree than 19 Celsius degree (P = 0.00). Dry matter, gross energy and energy from carbohydrate were more digestible as dietary carbohydrate levels increased, at both temperatures. Increasing dietary carbohydrate generated an increase in the intestinal activity of a-amylase, which was higher at 15 Celsius degree. Across the levels of dietary carbohydrate tested;there were no pathological changes to liver or intestine histology. Fish oil can be substituted with gelatinised carbohydrate under challenging high water temperatures in brook trout feeds, with no detriment to health, nutrient digestibility or growth performance.

History

Publication title

Animal Feed Science and Technology

Volume

193

Issue

2014

Pagination

111-123

ISSN

0377-8401

Department/School

Institute for Marine and Antarctic Studies

Publisher

Elsevier Science Bv

Place of publication

Po Box 211, Amsterdam, Netherlands, 1000 Ae

Rights statement

Copyright 2014 Elsevier BV

Repository Status

  • Restricted

Socio-economic Objectives

Fisheries - aquaculture not elsewhere classified

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