Effect of varying dietary protein level in different families of rainbow trout

Austreng, Erland; Refstie, Terje

doi:10.1016/0044-8486(79)90027-9

Cited by 73 publications

(22 citation statements)

References 17 publications

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“…Second, genetic correlations for DG, DFI and FE between diets were close to unity, indicating little re-ranking of families across the diets. These weak re-rankings agree with other farmed fish studies that have found little or no family interactions with diet nutrient levels [1,2,13,22,37] or production environments [20,44].…”

Section: Impacts Of G × E On Breeding Programmessupporting

confidence: 76%

“…Daily gain was calculated as the difference between the initial and the final body weights, divided by the number of days in the trial (77-80 d, depending on the tank). Individual DFI was calculated by fitting repeated measures analysis of variance with measurement time (1)(2)(3)(4)(5) as the random repeated factor, and then calculating least squares means for each individual (MIXED procedure, SAS  9.1; SAS  Inst. Inc., US).…”

Section: Traits Recordedmentioning

confidence: 99%

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Breeding salmonids for feed efficiency in current fishmeal and future plant-based diet environments

Quinton

Kause

Koskela³

et al. 2007

Genet Sel Evol

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-The aquaculture industry is increasingly replacing fishmeal in feeds for carnivorous fish with soybean meal (SBM). This diet change presents a potential for genotype-environment (G × E) interactions. We tested whether current salmonid breeding programmes that evaluate and select within fishmeal diets also improve growth and efficiency on potential future SBM diets. A total of 1680 European whitefish from 70 families were reared with either fishmeal-or SBM-based diets in a split-family design. Individual daily gain (DG), daily feed intake (DFI) and feed efficiency (FE) were recorded. Traits displayed only weak G × E interactions as variances and heritabilities did not differ substantially between the diets, and cross-diet genetic correlations were near unity. In both diets, DFI exhibited moderate heritability and had very high genetic correlation with DG whereas FE had low heritability. Predicted genetic responses demonstrated that selection to increase DG and FE on the fishmeal diet lead to favourable responses on the SBM diet. Selection for FE based on an index including DG and DFI achieved at least double FE gain versus selection on DG alone. Therefore, current breeding programmes are improving the biological ability of salmonids to use novel plant-based diets, and aiding the aquaculture industry to reduce fishmeal use.feed efficiency / genotype-environment interaction / selection / aquaculture / Coregonus

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Section: Impacts Of G × E On Breeding Programmessupporting

confidence: 76%

Section: Traits Recordedmentioning

confidence: 99%

Breeding salmonids for feed efficiency in current fishmeal and future plant-based diet environments

Quinton

Kause

Koskela³

et al. 2007

Genet Sel Evol

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“…In contrast what has been reported in earlier publications (Austreng and Refstie 1979;Refstie and Austreng 1981;Valente et al 1998), high-energy trout feed is now the standard feed of fish raised in fish farms (digestible energy: approx. 20 MJ kg -1 ).…”

Section: Introductioncontrasting

confidence: 51%

Digestibility in selected rainbow trout families and relation to growth and feed utilisation

Rasmussen

Jokumsen

2008

Aquacult Int

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Experiments have been carried out aimed at clarifying variations in the digestibility of dietary nutrients in rainbow trout families and studying how differences in digestibility may be related to growth and feed utilisation at various growth rates. The digestibility of protein, lipid, carbohydrates (nitrogen-free extracts, NFE) and dry matter was analysed in two experiments involving eight rainbow trout families [Ab, Ba, Cd, Dc (first study); V, X, Y, Z (second study)]. In the first experiment rainbow trout were reared for 128 days at 13.0°C, and in the second experiment, they were reared for 84 days at 16.8°C. In both experiments, the fish were fed ad libitum and reared from an initial weight of 70-100 g to a final weight of 500-700 g. When the fish reached a weight of approximately 200 g, some individuals were moved to another experimental system in which the digestibility of protein, lipid, nitrogen-free extracts and dry matter was measured. Taken as a whole, our results indicate that selective breeding still offers a large potential for improved growth and feed utilisation in rainbow trout strains. In the first study, family Dc showed a higher specific growth rate (SGR) than the other three families (P \ 0.05), and family Ba showed a lower feed conversion ratio (FCR) than family Ab (P \ 0.05); there were no observed differences in digestibility despite some differences in growth. In the second study, family Y grew faster than all of the other families (P \ 0.05), and family Z grew faster than families V and X (P \ 0.01). A comparable pattern was seen for FCR, with family Y utilising feed better than family V (P \ 0.05), and families V, Y and Z performing better than family X (P \ 0.001). Protein digestibility was higher in the two fastest growing families (Y and Z) than in the slower growing family X (P \ 0.05), while lipid digestion was higher in family Y than in family V (P \ 0.05). A comparison of the results from both experiments revealed that protein digestibility in particular was closely related to the SGR and the FCR at high growth rates. However, despite the advantageous protein digestibility on fish growth, analysis of the protein retention efficiency (PRE) showed that when protein was ingested in relatively large amounts, as in the fastest growing families, the ''excess'' nitrogen was excreted and therefore did not contribute to protein deposition in the fish body. Hence, the potential weight gain offered by improved protein digestibility does not materialise when the protein intake is above a certain level. Other factors must therefore explain the positive relation between fast growth and high protein digestibility.

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“…Metabolic faecal nitrogen is more correlated with dry feed intake than dietary protein content, with the result that the proportion of metabolic faecal nitrogen in faeces from fish fed low protein diets will be higher than for fish fed high protein diets. Furthermore, protein quality improves and the content of carbohydrates decreases with an increased dietary protein content, resulting in an increase in protein digestibility (Austreng and Refstie, 1978). However, it should be emphasized that the above findings have been obtained for diets with a single ingredient as the only source of dietary protein.…”

Section: Apparent Protein Digestibility Coefficientsmentioning

confidence: 50%

The error associated with the prediction of digestible protein contents of fish diets from tabulated values

Sales¹

2009

CZECH J ANIM SCI

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Numerous species available for culture, and lengthy, tedious and demanding digestibility experiments necessitate the use of tabulated values to calculate the apparent digestible nutrient contents of compound fish diets. The error associated with the above practice was evaluated in the present study with the use of apparent protein digestibility coefficients (APDCs) and dietary crude protein (CP) contents obtained in independent studies on fish nutrition. Prediction of APDCs of 21 compound diets evaluated in 18 studies with rainbow trout (<I>Oncorhynchus mykiss</I>), by using APDCs of 27 individual feed ingredients determined for this fish species, presented a mean prediction error (MPE) of 0.0489 between observed and predicted values. However, the above APDCs resulted in an overestimation of 7.86% (MPE = 0.0899) for APDCs of compound diets (<I>n</I> = 15) tested with 7 species other than rainbow trout. The CP contents of the above compound diets were overestimated with MPE’s of 0.3029 and 0.3200 for rainbow trout and other species, respectively, when using CP contents of individual feed ingredients as predictors. This eliminates the use of tabulated values to calculate apparent digestible protein contents of compound fish diets, except if databases are regularly updated with CP values for feed ingredients used.

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Effect of varying dietary protein level in different families of rainbow trout

Cited by 73 publications

References 17 publications

Breeding salmonids for feed efficiency in current fishmeal and future plant-based diet environments

Breeding salmonids for feed efficiency in current fishmeal and future plant-based diet environments

Digestibility in selected rainbow trout families and relation to growth and feed utilisation

The error associated with the prediction of digestible protein contents of fish diets from tabulated values

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