In vitro selenium accessibility in pet foods is affected by diet composition and type

Abstract

Se bioavailability in commercial pet foods has been shown to be highly variable. The aim of the present study was to identify dietary factors associated with in vitro accessibility of Se (Se A iv ) in pet foods. Se A iv is defined as the percentage of Se from the diet that is potentially available for absorption after in vitro digestion. Sixty-two diets (dog, n 52; cat, n 10) were in vitro enzymatically digested: fifty-four of them were commercially available (kibble, n 20; pellet, n 8; canned, n 17; raw meat, n 6; steamed meat, n 3) and eight were unprocessed (kibble, n 4; canned, n 4) from the same batch as the corresponding processed diets. The present investigation examined if Se A iv was affected by diet type, dietary protein, methionine, cysteine, lysine and Se content, DM, organic matter and crude protein (CP) digestibility. Se A iv differed significantly among diet types (P<0·001). Canned and steamed meat diets had a lower Se A iv than pelleted and raw meat diets. Se A iv correlated positively with CP digestibility in extruded diets (kibbles, n 19; r 0·540, P = 0·017) and negatively in canned diets (n 16; r - 0·611, P =0·012). Moreover, the canning process (n 4) decreased Se A iv (P =0·001), whereas extrusion (n 4) revealed no effect on Se A iv (P =0·297). These differences in Se A iv between diet types warrant quantification of diet type effects on in vivo Se bioavailability.