Effects of encapsulated niacin on metabolism and production of periparturient dairy cows

Abstract

Nicotinic acid (niacin) can suppress lipolysis, but responses to dietary niacin have been inconsistent in cattle. Our aim was to determine if 24 g/d of encapsulated niacin (EN; providing 9.6g/d of bioavailable nicotinic acid) alters lipid metabolism and productivity of transition cows. Beginning 21 d before expected calving, primiparous (n = 9) and multiparous (n = 13) cows (body condition score of 3.63 ± 0.08) were sequentially assigned within parity to EN (12 g provided with ration twice daily) or control through 21 d postpartum. Liver biopsies were collected on d -21, -4, 1, 7, and 21 relative to parturition. Blood samples were collected on d -21, -14, -7, -4, 1, 4, 7, 14, and 21 relative to parturition. On d 7 postpartum, a caffeine clearance test was performed to assess liver function, and on d 21 to 23 postpartum, blood samples were collected every 8h to monitor posttreatment nonesterified fatty acid (NEFA) responses. Data were analyzed using mixed models with repeated measures over time. A treatment × time × parity effect was observed on prepartum dry matter intake (DMI), which was caused by a 4 kg/d decrease in DMI of EN-treated multiparous cows compared with control multiparous cows during the final 4 d prepartum. A significant increase in plasma nicotinamide concentration occurred in EN-treated cows on d -7 and 21 relative to parturition. Prepartum glucose concentration decreased in treated animals, with no difference in plasma insulin concentration. Treatment × time × parity effects were detected for NEFA and β-hydroxybutyrate concentrations during the postpartum period. Plasma NEFA peaked at 1,467 ± 160 μM for control animals compared with 835 ± 154 μM for EN-treated animals. After treatments ended on d 21, no evidence was found for a plasma NEFA rebound in either parity group. A treatment × parity × time interaction was detected for liver triglyceride content, indicating a tendency for less liver triglyceride in EN-treated primiparous cows, but caffeine clearance rates were not affected by treatment. No treatment effects were observed for body condition score, body weight, energy balance, or milk or milk component production. A high dose of EN can decrease postpartum plasma NEFA concentration, but may also decrease prepartum DMI.

Effects of niacin supplementation (40 weeks) and two dietary levels of concentrate on performance, blood and fatty acid profiles of dairy cattle

“…Lactose concentration and yield were unaffected, similar to the results of Christensen et al (1992), Bernard et al (1995), Ottou et al (1995) and Minor et al (1998), in which 6 g/d to 12 g/d niacin were supplemented. Thus, 24 g supplemental niacin did not affect milk components, similar to the results of Morey et al (2011), in which 24 g/d/cow were applied, divided into two daily portions of encapsulated niacin. Reasons for differing results possibly include stage of lactation, quantity of niacin supplementation, feeding regimen, and time segment.…”

“…In contrast, in the present trial the researchers found significantly lower plasma glucose concentrations in cows that were receiving supplemental niacin compared with those on the unsupplemented diets. Also Morey et al (2011) found lower plasma glucose concentrations in niacin-supplemented cows, but only pre-partum and only in pluriparous cows. Morey et al (2011) found a parity effect pre-partum and a trend postpartum due to 24 g supplemental encapsulated niacin, while the present study detected a parity effect postpartum.…”

“…Also Morey et al (2011) found lower plasma glucose concentrations in niacin-supplemented cows, but only pre-partum and only in pluriparous cows. Morey et al (2011) found a parity effect pre-partum and a trend postpartum due to 24 g supplemental encapsulated niacin, while the present study detected a parity effect postpartum. Pluriparous cows developed significant lower plasma glucose concentrations than primiparous cows.…”

“…Therefore, the lower glucose concentrations cannot be explained by increased glucose clearance. However, the direct effects of niacin on plasma glucose, such as stimulating glucose utilization in peripheral tissues and suppressing glucose production by the liver, are not known (Morey et al, 2011).…”

“…In addition, Santschi et al (2005b) estimated that only 5% of supplemental nicotinic acid is bioavailable. Morey et al (2011) suggested most supplemented NA is converted to NAM after absorption. In the present study, only NAM could be found in plasma, supporting the assumption that supplemental niacin was converted to NAM, which might be the reason that NEFA did not decrease because of NA, which has a high affinity with the receptor (HM74A).…”