PSVII-20 - Effect of starch content in the concentrate of finishing bison on meat nutritional composition, quality, and palatability

Abstract: According to the Saskatchewan Bison Association, in the last few years producers have not been able to fill the increasing demand for bison meat. Indeed, one of the main challenges faced by the bison industry is their ability to produce a consistent product in a relatively short period of time. Hence, it is necessary to optimize the productivity and profitability of feeding bison calves while ensuring the quality of the end product. This study aimed to evaluate the effects of different starch contents in the concentrate of finishing bison on meat nutritional composition, quality, and palatability. Forty-eight yearling bison bulls (commercial Wood × Plains, 435 ± 13.4 kg body weight, BW) were homogenously distributed into 12 pens (4 bulls/pen) based on BW, and each pen randomly assigned (n=6) to receive either a high- (51.4% dry matter basis, DM; n=24 bison bulls) or moderate-starch (25.8% DM; n=24 bison bulls) concentrate, alongside free access to water and grass hay bales. After 156 d of feeding, bison bulls were slaughtered in a commercial abattoir in AB, Canada. At 3 d postmortem, color values were measured at the ribeye between the 11 and 12^th ribs. Subsequently, striploins from the left carcass sides were collected, weighed, vacuum packaged, and transported under refrigeration conditions to the AAFC-Lacombe Research and Development Centre, AB, Canada. On day 6 of ageing, striploins were unpacked and weighed to measure purge losses, and pH was collected. Subsequently, six 2.5-cm thick steaks were obtained for further nutritional analyses (minerals, cholesterol, vitamin B₃, protein, fat, moisture, and fatty acids), shear force, color in retail display for 4 d, and descriptive sensory and flavor profile analyses performed by trained panelists. The dietary starch content did not affect the nutritional composition as well as the pH, 3-d color values, moisture losses, and shear force value of the bison meat (P>0.1). However, the high-starch concentrate increased the meat luminosity (L*) after 4 d in retail display (P<0.05) and initial and overall tenderness (P<0.001), and decreased the amount of perceived connective tissue (P<0.001). Additionally, spongy and rubbery textures were less frequently found by trained panelists in meat from bison fed a high-starch than a moderate-starch concentrate (P<0.01 and 0.05, respectively). Regarding meat flavor, the high-starch concentrate decreased salty taste (P<0.05) and burnt and livery aromas (P=0.071 and 0.069, respectively) but increased metallic flavor (P<0.01) and bitter taste (P=0.076). In conclusion, the starch content in the concentrate of finishing bison did not affect the meat nutritional value. However, some positive effects on meat color and palatability were found when feeding bison a high-starch concentrate.