Relative bioavailability of carnitine delivered by ruminal or abomasal infusion or by encapsulation in dairy cattle

Abstract

Two studies were designed to evaluate the relative bioavailability of l-carnitine delivered by different methods in dairy cattle. In experiment 1, 4 Holstein heifers were used in a split-plot design to compare ruminally or abomasally infused l-carnitine. The study included 2 main-plot periods, with infusion routes allocated in a crossover design. Within main-plot periods, each of 3 subplot periods consisted of 4-d infusions separated with 4-d rest periods. Subplot treatments were infusion of 1, 3, and 6 g of l-carnitine/d in conjunction with 6 g/d of arabinogalactan given in consideration of eventual product manufacturing. Doses increased within a period to minimize carryover risk. Treatments were solubilized in 4 L of water and delivered in two 10-h infusions daily. Blood was collected before the start of infusion period and on d 4 of each infusion period to obtain baseline and treatment l-carnitine concentrations. There was a dose × route interaction and route effect for increases in plasma carnitine above baseline, with increases above baseline being greater across all dose levels when infused abomasally compared with ruminally. Results demonstrated superior relative bioavailability of l-carnitine when ruminal exposure was physically bypassed. In experiment 2, 56 lactating Holstein cows (143 ± 72 d in milk) were used in 2 cohorts in randomized complete block designs (blocked by parity and milk production) to evaluate 2 rumen-protected products compared with crystalline l-carnitine. Treatments were (1) control, (2) 3 g/d of crystalline l-carnitine (crystalline), (3) 6 g/d of crystalline, (4) 5 g/d of 40COAT (40% coating, 60% l-carnitine), (5) 10 g/d of 40COAT, (6) 7.5 g/d of 60COAT (60% coating, 40% l-carnitine), and (7) 15 g/d of 60COAT. Treatments were top-dressed to diets twice daily. Each cohort used 14-d and included a 6-d baseline measurement period with the final 2 d used for data and sample collection, and an 8-d treatment period with the final 2 d used for data and sample collection. Plasma, urine, and milk samples were analyzed for l-carnitine. Crystalline and 40COAT linearly increased plasma l-carnitine, and 60COAT tended to linearly increase plasma l-carnitine. Total excretion (milk + urine) of l-carnitine averaged 1.52 ± 0.04 g/d in controls, increased linearly with crystalline and 40COAT, and increased quadratically with 60COAT. Crystalline increased plasma l-carnitine and l-carnitine excretion more than 40COAT and 60COAT. In conclusion, preventing ruminal degradation of l-carnitine increased delivery of bioavailable carnitine to cattle, but effective ruminal protection and postruminal bioavailability is challenging.

Rumen‐protected l‐carnitine supplementation during mating period altered metabolic status and reproductive performance of ewes

“…Dosages of LC as high as 100 g/day resulted in apparent lower feed intake in dairy cows during the first 14 days postpartum (Carlson et al, 2007), which could indicate high ATP synthesis in the liver. Olagaray et al (2018) revealed a tendency for higher feed intake in heifers infused with 3 g/day LC, whereas dietary supplementation of 7.5 g LC decreased DMI in mid‐lactating cows. The authors stated the interactions with the metabolic stage of the animals as a potent factor for the observed inconsistent impact of LC on animals feed intake.…”

Peripartal Rumen-Protected L-Carnitine Manipulates the Productive and Blood Metabolic Responses in High-Producing Holstein Dairy Cows

“…Therefore, dairy cattle during the transition from gestation to lactation requires substantial nutrients to shift their situation (48). Previous studies claimed that increasing the energy availability of the transition diet through L-carnitine supplementation may have some benefits (26,49), allowing the animals to adapt and decrease fatty acid mobilization from adipose tissue, eventually being less prone to lipid-related metabolic disorders (50). Hence, following parturition, this resulted in cows showing a better milk production and composition responses as those observed in the present work.…”

“…Olagaray et al (49) reported that fatty liver is a metabolic disease that occurs during the first few weeks of lactation and affects up to 50% of dairy cows. Higher incidence of fatty liver accompanies with a decline in the concentration of free carnitine.…”