The evaluation of energy in fish feed

Mahmoud Haidar

Research output: Thesisinternal PhD, WUAcademic

Abstract

New and alternative plant ingredients are increasingly incorporated in fish feed due to the scarcity of captured fish and increased fishmeal and fish oil prices. As a result, current fish feeds are characterized by a highly variable ingredients composition, leading to a similar variability in the dietary macronutrients composition, especially the carbohydrates fraction. Appropriate formulation of the energy component in fish feeds requires information on nutrient digestibility, energy requirements for maintenance, and the efficiency of utilization of digestible energy for growth (kgDE). In fish feed formulation, the energy evaluation is based on digestible energy (DE) basis. The main assumptions of this DE system are that maintenance requirements and kgDE are independent of dietary factors. The main objective of this thesis was to evaluate and improve the DE system for Nile tilapia. Data showed that, opposite to what is assumed in literature and irrespective of the feeding level applied, an optimal digestible protein to digestible energy ratio (DP/DE) for young Nile tilapia could not be detected. In addition, it was expected that Nile tilapia would show a maximal protein deposition in relation to a wide range of DP/DE ratios, however, this was either observed. Further investigations showed that different body compartments/organs responded differently in terms of protein and fat composition as a result of changes in the dietary DP/DE ratio. In tilapia, viscera and the “rest” fraction (head, skin, fins and bones) were the main site for fat retention. In addition, protein content of fillets seems to be constant (about 17%) and not affected by dietary factors in Nile tilapia. In addition, the effect of using new plant ingredients in Nile tilapia diets was also investigated. The results showed that the ingredients composition had an effect on the maintenance requirements of Nile tilapia. Further, changes in the ratio of starch vs non starch carbohydrates revealed that energy retention was lower when more dietary fibers were included. In addition, the net energy retention differed also when the levels of digestible protein, fat and carbohydrates changed in the diets. The latter results proved that kgDE was not constant and was dependent on diet composition. All aforementioned results led us to calculate the energetic efficiencies of digestible protein, fat and carbohydrates for net energy retention. These estimated efficiencies were used to propose a net energy evaluation system being feasible for Nile tilapia.

LanguageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Verreth, Johan, Promotor
  • Schrama, Johan, Co-promotor
Award date17 Nov 2017
Place of PublicationWageningen
Publisher
Print ISBNs9789463438049
DOIs
Publication statusPublished - 2017

Fingerprint

digestible energy
Oreochromis niloticus
fish feeds
digestible protein
energy
ingredients
diet
lipids
carbohydrates
starch
Tilapia (Cichlidae)
carbohydrate composition
protein deposition
feed formulation
animal organs
energy efficiency
feeding level
fillets
fish meal
fish oils

Keywords

  • oreochromis niloticus
  • fish feeding
  • feed formulation
  • digestible energy
  • dietary protein
  • dietary fat
  • carbohydrates
  • growth
  • feed evaluation
  • fish culture
  • aquaculture

Cite this

Haidar, M. (2017). The evaluation of energy in fish feed. Wageningen: Wageningen University. https://doi.org/10.18174/424414
Haidar, Mahmoud. / The evaluation of energy in fish feed. Wageningen : Wageningen University, 2017. 155 p.
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title = "The evaluation of energy in fish feed",
abstract = "New and alternative plant ingredients are increasingly incorporated in fish feed due to the scarcity of captured fish and increased fishmeal and fish oil prices. As a result, current fish feeds are characterized by a highly variable ingredients composition, leading to a similar variability in the dietary macronutrients composition, especially the carbohydrates fraction. Appropriate formulation of the energy component in fish feeds requires information on nutrient digestibility, energy requirements for maintenance, and the efficiency of utilization of digestible energy for growth (kgDE). In fish feed formulation, the energy evaluation is based on digestible energy (DE) basis. The main assumptions of this DE system are that maintenance requirements and kgDE are independent of dietary factors. The main objective of this thesis was to evaluate and improve the DE system for Nile tilapia. Data showed that, opposite to what is assumed in literature and irrespective of the feeding level applied, an optimal digestible protein to digestible energy ratio (DP/DE) for young Nile tilapia could not be detected. In addition, it was expected that Nile tilapia would show a maximal protein deposition in relation to a wide range of DP/DE ratios, however, this was either observed. Further investigations showed that different body compartments/organs responded differently in terms of protein and fat composition as a result of changes in the dietary DP/DE ratio. In tilapia, viscera and the “rest” fraction (head, skin, fins and bones) were the main site for fat retention. In addition, protein content of fillets seems to be constant (about 17{\%}) and not affected by dietary factors in Nile tilapia. In addition, the effect of using new plant ingredients in Nile tilapia diets was also investigated. The results showed that the ingredients composition had an effect on the maintenance requirements of Nile tilapia. Further, changes in the ratio of starch vs non starch carbohydrates revealed that energy retention was lower when more dietary fibers were included. In addition, the net energy retention differed also when the levels of digestible protein, fat and carbohydrates changed in the diets. The latter results proved that kgDE was not constant and was dependent on diet composition. All aforementioned results led us to calculate the energetic efficiencies of digestible protein, fat and carbohydrates for net energy retention. These estimated efficiencies were used to propose a net energy evaluation system being feasible for Nile tilapia.",
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Haidar, M 2017, 'The evaluation of energy in fish feed', Doctor of Philosophy, Wageningen University, Wageningen. https://doi.org/10.18174/424414

The evaluation of energy in fish feed. / Haidar, Mahmoud.

Wageningen : Wageningen University, 2017. 155 p.

Research output: Thesisinternal PhD, WUAcademic

TY - THES

T1 - The evaluation of energy in fish feed

AU - Haidar, Mahmoud

N1 - WU thesis 6810 Includes bibliographical references. - With summary in English

PY - 2017

Y1 - 2017

N2 - New and alternative plant ingredients are increasingly incorporated in fish feed due to the scarcity of captured fish and increased fishmeal and fish oil prices. As a result, current fish feeds are characterized by a highly variable ingredients composition, leading to a similar variability in the dietary macronutrients composition, especially the carbohydrates fraction. Appropriate formulation of the energy component in fish feeds requires information on nutrient digestibility, energy requirements for maintenance, and the efficiency of utilization of digestible energy for growth (kgDE). In fish feed formulation, the energy evaluation is based on digestible energy (DE) basis. The main assumptions of this DE system are that maintenance requirements and kgDE are independent of dietary factors. The main objective of this thesis was to evaluate and improve the DE system for Nile tilapia. Data showed that, opposite to what is assumed in literature and irrespective of the feeding level applied, an optimal digestible protein to digestible energy ratio (DP/DE) for young Nile tilapia could not be detected. In addition, it was expected that Nile tilapia would show a maximal protein deposition in relation to a wide range of DP/DE ratios, however, this was either observed. Further investigations showed that different body compartments/organs responded differently in terms of protein and fat composition as a result of changes in the dietary DP/DE ratio. In tilapia, viscera and the “rest” fraction (head, skin, fins and bones) were the main site for fat retention. In addition, protein content of fillets seems to be constant (about 17%) and not affected by dietary factors in Nile tilapia. In addition, the effect of using new plant ingredients in Nile tilapia diets was also investigated. The results showed that the ingredients composition had an effect on the maintenance requirements of Nile tilapia. Further, changes in the ratio of starch vs non starch carbohydrates revealed that energy retention was lower when more dietary fibers were included. In addition, the net energy retention differed also when the levels of digestible protein, fat and carbohydrates changed in the diets. The latter results proved that kgDE was not constant and was dependent on diet composition. All aforementioned results led us to calculate the energetic efficiencies of digestible protein, fat and carbohydrates for net energy retention. These estimated efficiencies were used to propose a net energy evaluation system being feasible for Nile tilapia.

AB - New and alternative plant ingredients are increasingly incorporated in fish feed due to the scarcity of captured fish and increased fishmeal and fish oil prices. As a result, current fish feeds are characterized by a highly variable ingredients composition, leading to a similar variability in the dietary macronutrients composition, especially the carbohydrates fraction. Appropriate formulation of the energy component in fish feeds requires information on nutrient digestibility, energy requirements for maintenance, and the efficiency of utilization of digestible energy for growth (kgDE). In fish feed formulation, the energy evaluation is based on digestible energy (DE) basis. The main assumptions of this DE system are that maintenance requirements and kgDE are independent of dietary factors. The main objective of this thesis was to evaluate and improve the DE system for Nile tilapia. Data showed that, opposite to what is assumed in literature and irrespective of the feeding level applied, an optimal digestible protein to digestible energy ratio (DP/DE) for young Nile tilapia could not be detected. In addition, it was expected that Nile tilapia would show a maximal protein deposition in relation to a wide range of DP/DE ratios, however, this was either observed. Further investigations showed that different body compartments/organs responded differently in terms of protein and fat composition as a result of changes in the dietary DP/DE ratio. In tilapia, viscera and the “rest” fraction (head, skin, fins and bones) were the main site for fat retention. In addition, protein content of fillets seems to be constant (about 17%) and not affected by dietary factors in Nile tilapia. In addition, the effect of using new plant ingredients in Nile tilapia diets was also investigated. The results showed that the ingredients composition had an effect on the maintenance requirements of Nile tilapia. Further, changes in the ratio of starch vs non starch carbohydrates revealed that energy retention was lower when more dietary fibers were included. In addition, the net energy retention differed also when the levels of digestible protein, fat and carbohydrates changed in the diets. The latter results proved that kgDE was not constant and was dependent on diet composition. All aforementioned results led us to calculate the energetic efficiencies of digestible protein, fat and carbohydrates for net energy retention. These estimated efficiencies were used to propose a net energy evaluation system being feasible for Nile tilapia.

KW - oreochromis niloticus

KW - fish feeding

KW - feed formulation

KW - digestible energy

KW - dietary protein

KW - dietary fat

KW - carbohydrates

KW - growth

KW - feed evaluation

KW - fish culture

KW - aquaculture

KW - oreochromis niloticus

KW - visvoeding

KW - voersamenstelling

KW - verteerbare energie

KW - voedingseiwit

KW - voedingsvet

KW - koolhydraten

KW - groei

KW - voederwaardering

KW - visteelt

KW - aquacultuur

U2 - 10.18174/424414

DO - 10.18174/424414

M3 - internal PhD, WU

SN - 9789463438049

PB - Wageningen University

CY - Wageningen

ER -

Haidar M. The evaluation of energy in fish feed. Wageningen: Wageningen University, 2017. 155 p. https://doi.org/10.18174/424414