Milk composition in free-ranging polar bears (Ursus maritimus) as a model for captive rearing milk formula.

The goals of this study were to have an improved understanding of milk composition and to help create a suitable milk formula for cubs raised in captivity. Milk samples were evaluated for fat, fatty acids, carbohydrate, vitamin D(3), 25(OH)D(3), vitamin A (retinol), vitamin E (α-tocopherol), protein, and amino acids. Total lipids in milk did not differ for cubs (mean ± SEM = 26.

Bioavailability of lysine for kittens in overheated casein is underestimated by the rat growth assay method.

Growth assays were performed to determine lysine bioavailability for kittens and rats in untreated and heated casein; these values were compared with estimates obtained with an in vitro method. Body weight, food intake, nitrogen and dry matter digestibility, and plasma lysine were determined during an 80-day growth trial using kittens (n = 16). Body weight and food intake were determined during a 21-day growth trial using weanling rats (n = 80).

Does taurine deficiency cause metabolic bone disease and rickets in polar bear cubs raised in captivity?

Rickets and fractures have been reported in captive polar bears. Taurine (TAU) is key for the conjugation of ursodeoxycholic acid (UDCA), a bile acid unique to bears. Since TAU-conjugated UDCA optimizes fat and fat-soluble vitamin absorption, we asked if TAU deficiency could cause vitamin D malabsorption and lead to metabolic bone disease in captive polar bears.

Urinary felinine excretion in intact male cats is increased by dietary cystine.

Felinine is a branched-chain sulfur amino acid present in the urine of certain Felidae, including domestic cats. The objective of the present study was to determine if additional cystine and/or dietary N would increase felinine and N-acetylfelinine excretion by intact male cats fed a low-protein(LP) diet. Feeding five adult intact male cats an LP diet (18.

Dietary crude protein has minimal effect on the activity of selected enzymes of methionine catabolism in kittens fed diets near-limiting in methionine.

Previous experiments have shown that increasing the dietary crude protein (CP) of cats does not increase urea cycle enzymes or alanine amino transferase as occurs in rats. Also when an essential amino acid (EAA) is limiting in a diet for growing kittens, the kittens do not exhibit an amino acid imbalance when other EAAs are added to the diet. To study the metabolic basis for these observations which are different from that found in omnivores and herbivores, the hypothesis that increased dietary CP decreases methionine catabolism, so more is spared for growth, was tested.