Feeding increasing amounts of ruminally protected choline decreased fatty liver in nonlactating, pregnant Holstein cows in negative energy status

Abstract

The objectives were to determine the optimal feeding amount of choline in a ruminally protected form to reduce the triacylglycerol (TAG) concentration in liver and to increase TAG in blood plasma of dairy cows. Pregnant, nonlactating multiparous Holstein cows (n = 77) were blocked by body condition score (3.59 ± 0.33) and assigned to treatment at 64 ± 10 d before calculated calving date. Dietary treatments were top-dressing of 0, 30, 60, 90, or 120 g/d of ruminally protected choline (RPC; Balchem Corp., New Hampton, NY) ions to supply the equivalent of 0, 6.5, 12.9, 19.4, and 25.8 g/d of choline ions. Diets were formulated to exceed nutrient requirements for maintenance and pregnancy and fed in ad libitum amounts for the first 5 d. From d 6 to 15, cows were restricted to consume approximately 31% of their net energy requirements to simulate early lactating cows in negative energy balance. Methionine intake was maintained throughout each 15-d period. Liver was biopsied at 5 and 14 d and analyzed for TAG and glycogen. Blood was sampled on d 5 and 14 and plasma analyzed for glucose, insulin, cholesterol, β-hydroxybutyrate, long-chain fatty acids, and haptoglobin. On d 14, a mixture of saturated long-chain fatty acids, ground corn, and dried molasses (50:37:13) was offered (908 g, as-is basis) 10 h after the single daily feeding. Blood samples were collected for 19 h and plasma analyzed for TAG and cholesterol to assess apparent absorption of dietary fat. Mean dry matter intake and energy balance decreased from means of 9.5 to 3.3 kg/d and from 0.6 to -9.2 Mcal of net energy for lactation/d during the ad libitum and restricted feeding periods, respectively. Plasma concentrations of the lipid-soluble choline biomolecules, namely total phosphatidylcholines, total lysophosphatidylcholines, and sphingomyelin, increased with choline supplementation. Feed restriction increased plasma concentrations of β-hydroxybutyrate and free long-chain fatty acids, whereas those of glucose, insulin, and total cholesterol decreased. During feed restriction, concentration of hepatic TAG and plasma haptoglobin decreased linearly, whereas concentration of hepatic glycogen tended to increase quadratically with increasing intake of RPC. After fat supplementation, mean plasma concentration of TAG increased by an average of 21% with intake of RPC ions, peaking at intakes of ≥6.5 g/d of RPC ion. In summary, feeding RPC ions to cows in negative energy balance had increasing lipotropic effects on the liver when consumed up to 25.8 g/d, whereas feeding only 6.5 g/d increased concentrations of hepatic glycogen and TAG in the blood.

Responses to rumen-protected choline in transition cows do not depend on prepartum body condition

“…Choline has well-demonstrated lipotropic effects in laboratory animals (Cole et al, 2012) and dairy cows (Cooke et al, 2007;Elek et al, 2013;Zenobi et al, 2018b), and overconditioned prepartum dairy cows have an increased risk of fatty liver (Bobe et al, 2004). Therefore, it is reasonable to suggest that potential effects of choline on improving lipid intermediary metabolism and lactation performance might be more easily observed in cows at an increased risk for hepatic lipido-Bollatti et al: RUMEN-PROTECTED CHOLINE AND BODY CONDITION Table 3.…”

“…lipids in part because of a small content of phosphatidylcholine in the intestine (da Silva et al, 2015), which impairs the secretion of chylomicron into lymph (Takahashi et al, 1982). In nonlactating dairy cows after feed restriction and subsequent fat challenge, RPC increased mean plasma concentration of triacylglycerol compared with nonsupplemented controls (Zenobi et al, 2018b), thereby suggesting that choline enhances the absorptive capacity of the gastrointestinal tract. Therefore, it is possible that nutrient absorption might be improved by choline, particularly lipids.…”

“…Changes in gut permeability could potentially facilitate the entry of antigens into the bloodstream and elicit an inflammatory response [i.e., induce an acute phase response (Kvidera et al, 2017)]. Zenobi et al (2018b) subjected cows to feed restriction in an attempt to mimic the negative energy balance observed in early lactation. The authors observed that increasing the amount of RPC fed to feed-restricted cows linearly reduced the concentrations of haptoglobin in plasma (Zenobi et al, 2018b).…”

“…Zenobi et al (2018b) subjected cows to feed restriction in an attempt to mimic the negative energy balance observed in early lactation. The authors observed that increasing the amount of RPC fed to feed-restricted cows linearly reduced the concentrations of haptoglobin in plasma (Zenobi et al, 2018b). It remains unknown if choline, its metabolites, or both have a direct effect on immune cells or if the effects are mediated by a potential constitutive role on gastrointestinal integrity, or a combination of both.…”

The role of micronutrients in high-yielding dairy ruminants: Choline and vitamin E

“…These results seem to be in contrast with several studies in which choline was shown to improve the metabolic health and liver function (5,12,13,26,30). In fact, Zenobi et al (44) stated that feeding pregnant, nonlactating Holstein cows with increasing amounts of RPC (from 0 to 25.8 g/d) decreased the concentration of hepatic triglycerides in a linear manner. Dietary choline thus seems to improve fat metabolism in the liver and increase the apparent absorption/traffic of triglycerides in the bloodstream, further confirming the beneficial effects of supplemental RPC for adult ruminants.…”