Amino acid availability of protein meals of different quality for adult and growing mink (Neovison vison)

ABSTRACT

Protein and amino acid (AA) availability of three protein meals of expected different quality were evaluated in young growing and adult mink. Lamb meal (LM), poultry meal (PM) or fishmeal (FM) were used as main protein sources in three extruded diets investigated by determining apparent total tract digestibility (ATTD) and nitrogen balance in 12 growing mink males aged 8–11 weeks in a Latin square design. In adult mink, ATTD of the diets was determined. The diets had lower protein content than recommended for growing mink, protein contributing 23% of total metabolisable energy (ME), to ensure differences in growth response. The LM diet with expected low protein quality revealed lower content of essential AA than the PM and FM diets. The ATTD of major nutrients and essential AA was significantly affected by diet, with the poorest values for LM, intermediate for PM and the highest values for FM. Mink kits revealed lower ATTD values than adults for protein, AA and especially fat, resulting in lower dietary ME content for kits than for adults. The mean difference was greatest for the LM diet with lowest ATTD and smallest for the FM diet with the highest ATTD. Nitrogen retention and growth rate differed significantly among diets and was lowest for diet LM and highest for diet FM, respectively. Different dietary essential AA contents and ATTD, especially of methionine, were the main factors to explain the difference in growth response. Generally, plasma essential AA concentrations did not clearly reflect the different dietary supply and the different growth response. The study shows that a recommended level of 0.31 g apparent total tract digestible methionine per MJ ME covers the minimum requirement with a safety margin. To obtain optimal growth, the lower digestive capacity in young mink kits should be considered when choosing feed ingredients.

KEYWORDS:

• Age differences
• animal proteins
• digestibility
• mink
• nitrogen balance
• performance
• protein efficiency ratio

Acknowledgments

We acknowledge the technical staff at the research farms at the Norwegian University of Life Sciences and University of Copenhagen for taking good care of the animals.

Availability of data and material

The datasets used during this study are available from the corresponding author on reasonable request.

Disclosure statement

No potential conflict of interest was reported by the authors.

Study design

Study design and interpretation of the results have been performed by the researchers. Planning, design and performance of the Norwegian study was done by MTT, AHT and ØA. The Danish part of the study was planned by AHT and ØA and carried out by AHT and CFM. Writing of the manuscript was mainly done by MTT with contributions from AHT, CFM and ØA.

Additional information

Funding

Sources of funding have been the Norwegian University of Life Sciences, Ås, Norway and Felleskjøpet Fôrutvikling, Trondheim, Norway [Project No: 817163].