Effects of substitution of dietary protein with carbohydrate on lactation performance in the mink (<i>Mustela vison</i>)

Abstract

Thirty mink dams nursing litters of 6 kits were assigned to one of 3 dietary treatments to investigate the effects of changing the protein:carbohydrate ratio on nutrient utilization, heat production, milk production and kit growth. Three diets were formulated to contain 65:3 (LC), 48:15 (MC) or 34:33 (HC) % of the metabolizable energy (ME) from protein and carbohydrate, respectively. The diets were fed ad libitum for 4 weeks from parturition. Twelve dams were held in an intensive care unit and subjected to balance and respiration experiments and the kits were injected with deuterium oxide to measure water kinetics and milk production. Eighteen dams were kept under normal farm conditions and feed intake of dams and weight gain of the kits were determined. Milk samples were collected from the dams. Metabolizable energy intake was not affected by dietary treatment. Carbohydrates were efficiently utilized with a digestibility coefficient of 84% in dams fed the HC diet. Dams fed the HC diet had a lower (PO.05) percentage weight loss, lower (PO.05) total heat production (HE), lower (P<0.05) protein oxidation (OXP), lower (P<0.05) water intake and a lower (P<0.05) nitrogen (N) excretion than dams fed the LC diet. Milk production, and thereby liveweights of the kits 4 weeks post partum, was higher (P<0.05) in dams fed the HC diet than in dams fed the LC diet. In conclusion, lactating mink dams are able to utilize digestible carbohydrates with positive effects on lactation performance and reduced nitrogen excretion.

Methodological considerations as to quantify nutrient and energy metabolism in lactating sows

“…This approach is described for mink to separate total HE of lactating mink dams and suckling kits measured by indirect calorimetry (Fink, 2004). Raising the liveweight of individual piglets to the power of 0.75 and taking the sum gave the metabolic liveweight of the litter.…”

Foetal life protein restriction in male mink (Neovison vison) kits lowers post-weaning protein oxidation and the relative abundance of hepatic fructose-1,6-bisphosphatase mRNA

“…Further, Russell et al (2002) found that protein oxidation was correlated to some extent to dietary protein intake in cats, but only if the protein requirement was met (Green et al, 2008). Studies in mink have, however, shown that the rates of amino acid decarboxylation (Tauson et al, 2001) and protein oxidation are regulated according to the dietary protein supply, even if the level of dietary protein is low (Fink et al, 2004) or below the requirement (Matthiesen et al, 2010a). These findings indicate some metabolic flexibility in the strict carnivores.…”

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.…”