nr: Nutrient retention (NR)

In aquacultuR: A Comprehensive R Tool for Zootechnical Metrics

Nutrient retention (NR)

Description

Function to calculate the Nutrient Retention (NR). The NR belongs to the Nutrient Use Efficiency metrics and is a measure for the proportion of a consumed nutrient that is retained in the tissue.

Usage

nr(ibw, fbw, ibn, fbn, fi, nut_f, dm = 1, dm_ib = 1, dm_fb = 1)

Arguments

ibw	numeric; initial weight in grams
fbw	numeric; final weight in grams
ibn	numeric; initial mass fraction of the target nutrient in the tissue of the experimental animal (on dry matter basis). The value must be between 0 and 1.
fbn	numeric; final mass fraction of the target nutrient in the tissue of the experimental animal (on dry matter basis). The value must be between 0 and 1.
fi	numeric; mass of feed given.
nut_f	numeric; mass fraction of nutrient in the diet. The value must be between 0 and 1.
dm	numeric; dry matter content of feed. Default is 1.
dm_ib	numeric; initial dry matter content of body tissue. Default is 1.
dm_fb	numeric; final dry matter content of body tissue. Default is 1.

Value

a numeric value. Multiply by 100 to convert into percentage.

Author(s)

Anıl Axel Tellbüscher

References

Willer, D.F., Newton, R., Malcorps, W. et al. Wild fish consumption can balance nutrient retention in farmed fish. Nat Food 5, 221–229 (2024). https://doi.org/10.1038/s43016-024-00932-z

Examples

# initial bodyweight = 10 g (0.01 kg)
# final bodyweight = 100 g (0.1 kg)
# initial mass fraction of N = 128 g/kg (80% CP on DM basis)
# final mass fraction of N = 132 g/kg (82.5% CP on DM basis)
# feed intake = 200 g (0.2 kg)
# N in feed = 72 g/kg (45% CP)

nr(10, 100, 0.128, 0.132, 200, 0.072) * 100

# 82.7% of the provided N has been retained


# multiple fish
nr(ibw = 10, fbw = c(93, 102, 99, 98, 101, 132),
   ibn = 0.128, fbn = 0.132,
   fi = 200, nut_f = 0.072)

aquacultuR documentation built on Jan. 26, 2026, 5:07 p.m.