A first estimate of the amino acid requirement for milk production of the high‐producing female mink (Mustela vison)

Abstract

Thirty mink dams nursing litters of six kits were assigned to one of three dietary treatments [high protein (HP), medium protein (MP) and low protein (LP)], fed ad libitum for 4 week from parturition, to investigate the effects of protein supply on milk yield and milk composition in order to estimate the amino acid requirement of the lactating mink. Twelve dams were held in an intensive care unit and subjected to balance experiments and the kits were injected with deuterium oxide to determine water kinetics and milk yield. Eighteen dams were kept under normal farm conditions but with feed intake of dams and live weight gain of kits being determined and milk samples collected. The ME intake was higher (p < 0.05) in dams fed the LP and MP diets than in dams fed the HP diet, whereas the amino acid intake (g/day) was lowest (p < 0.05) in dams fed the LP diet. In the third and fourth weeks of lactation milk yield was higher (p < 0.05) in dams fed the LP and MP diets than in dams fed the HP diet. Chemical composition of milk was not affected (p > 0.05) by dietary treatment. However, protein content tended (p = 0.06) to be lower in dams fed the LP diet. Amino acid content (g/16 g N) of milk was higher (p < 0.05) in dams fed the LP and MP diets than in dams fed the HP diet. This resulted in the highest (p < 0.05) amino acid intake and highest (p < 0.001) live weights of kits nursed by dams fed the LP and MP diets, which may be explained by a combined effect of higher ME intake and reduced energetic costs for glucose production through less amino acids being used in gluconeogenesis. In conclusion, the improved performance of dams fed the LP diet suggested that their requirement of essential amino acids and non-specific N were covered, and the requirement of digestible amino acids of lactating mink (kg(0.75)) was, thereby, estimated by use of a factorial approach including the amino acid excretion in milk of LP dams.

Chemical and amino acid composition of colostrum and mature milk differ only slightly in mink (Mustela vison)

“…In this experiment, the amino acid composition is expressed in relation to the total amino acid content, and corresponded in general to earlier results regarding mink found by Tauson et al. (2005) and Fink et al (2006), except for the valine content being approximately 25% higher. This may be explained by difference in corrections due to loss during hydrolysis.…”

Metabolic and growth response of mink (Neovison vison) kits until 10 weeks of age when exposed to different dietary protein provision

“…In previous studies, mink dams fed a diet containing 30% of ME from protein have been shown to have a superior milk yield and be raising kits that gained more weight Archives of Animal Nutrition 247 during their first four weeks of life than kits raised by dams given diets containing high (60% of ME) and medium (45% of ME) protein supply (Fink et al 2004(Fink et al , 2006. These studies did, however, not go beyond a kit age of four weeks and therefore the impact of protein supply on kit body gain and performance in the transition period from milk to solid feed was not evaluated.…”

“…However, the knowledge on the protein and amino acid requirements for late gestation and lactation in e.g. Lactating mink dams though may actually benefit from diets with lower than conventional protein content: when the dietary protein supply was reduced to 30% of metabolisable energy (ME) and replaced with readily digestible carbohydrates, milk yield of the dams was improved and this was consequently reflected in improved kit growth during the first four weeks of lactation (Fink et al 2004(Fink et al , 2006. For cats, NRC (2006) states that the requirement has not been investigated in detail, but that it is not likely to be higher than in young growing kittens for which solid recommendations exist.…”

“…cat and mink is still incomplete. In recent years, several investigations indicate that strict carnivores like the mink, or cat, are capable to adapt to a wide range of protein supplies by regulating their protein oxidation rate, and by adjustments in the liver and kidney mass (mink: Fink et al 2004Fink et al , 2006Fink et al , 2007Matthiesen et al 2010Matthiesen et al , 2012cat: Russell et al 2002;Green et al 2008). Lactating mink dams though may actually benefit from diets with lower than conventional protein content: when the dietary protein supply was reduced to 30% of metabolisable energy (ME) and replaced with readily digestible carbohydrates, milk yield of the dams was improved and this was consequently reflected in improved kit growth during the first four weeks of lactation (Fink et al 2004(Fink et al , 2006.…”

Late development of homoeothermy in mink (Mustela vison) kits – a strategy for maximum survival rate*

“…Mink kits are, however, capable of very rapid growth during the suckling period (Tauson, 1994), the growth rate being supported by the mink dams’ capacity for a high milk yield compared to its body size (Fink et al., 2004, 2005). Lactation is very energy‐demanding, and for animals living in the wild the dam will have to leave the nest for protracted time periods in order to seek prey.…”