Net nutrient absorption and liver metabolism in lactating dairy cows fed supplemental dietary biotin

Abstract

The effect of feeding supplemental biotin on net absorption and metabolism of nutrients by the portal-drained viscera (PDV; the gut, pancreas, spleen and associated fat) and liver of lactating dairy cows was measured. Three cows in early to mid-lactation catheterised for measurements of net nutrient absorption and metabolism by the PDV and liver were fed a total-mixed ration with or without supplemental biotin at 20 mg/day using a switch-back design (ABA v. BAB) with three 2-week periods. There were no effects of feeding biotin on dry matter intake (22.2 kg/day), milk yield (29.5 kg/day) or milk composition. There was also no effect of feeding biotin on net release of glucose by the liver, net liver removal of glucose precursors (propionate, alanine, lactate) or net liver release of b-hydroxybutyrate. Feeding biotin increased net PDV release of ammonia. Reasons for the response are not certain, but a numerical increase in net PDV release of acetate suggests that rumen or hindgut fermentation was altered. Results of the present study do not support the hypothesis that supplemental biotin increases liver glucose production in lactating dairy cows.

Effects of rumen-protected biotin on the growth performance, nitrogen utilization and blood parameters of yearling Liaoning cashmere doelings

“…Similar to most studies [26,27], the present study observed no effect on plasma glucose with biotin supplementation, but some studies have observed an increase [23]. Research has indicated that a large proportion of propionate is metabolized in the rumen wall, where it enters the gluconeogenic pathway, drastically reducing glucose utilization by gastrointestinal tissues and leaving more glucose available for other tissues [22].…”

Effects of biotin and coated cobalamin on lactation performance, nutrient digestion and rumen fermentation in Holstein dairy cows

“…However, blood glucose and insulin concentrations were unchanged with BI addition, and were consistent with the limited milk lactose yield response. Furthermore, other studies found that supplementing 20 mg/day of BI in dairy cow diets had no effect on pyruvate carboxylase and propionyl‐CoA carboxylase gene expressions and glucose net release in the liver (Ferreira & Weiss, 2007; Reynolds et al, 2007). Zimmerly and Weiss (2001) and Reynolds et al (2007) also reported unaltered blood glucose and insulin concentrations with BI addition in dairy cows.…”

“…Furthermore, other studies found that supplementing 20 mg/day of BI in dairy cow diets had no effect on pyruvate carboxylase and propionyl‐CoA carboxylase gene expressions and glucose net release in the liver (Ferreira & Weiss, 2007; Reynolds et al, 2007). Zimmerly and Weiss (2001) and Reynolds et al (2007) also reported unaltered blood glucose and insulin concentrations with BI addition in dairy cows. These results above showed that supplementing BI probably could not increase glucose supply of dairy cows.…”