Short-term feed intake is regulated by macronutrient oxidation in lactating Holstein cows

Abstract

In addition to plasma metabolites and hormones participating as humoral signals in the control of feed intake, oxidative metabolic processes in peripheral organs also generate signals to terminate feeding. Although the degree of oxidation over longer periods is relatively constant, recent work suggests that the periprandial pattern of fuel oxidation is involved in regulating feeding behavior in the bovine. However, the association between periprandial oxidative metabolism and feed intake of dairy cows has not yet been studied. Therefore, the aim of this study was to elucidate possible associations existing between single feed intake events and whole-body net fat and net carbohydrate oxidation as well as their relation to plasma metabolite concentrations. To this end, 4 late-lactating cows equipped with jugular catheters were kept in respiratory chambers with continuous and simultaneous recording of gas exchange and feed intake. Animals were fed ad libitum (AL) for 24 h and then feed restricted (RE) to 50% of the previous AL intake for a further 24 h. Blood samples were collected hourly to analyze β-hydroxybutyrate (BHBA), glucose, nonesterified fatty acids (NEFA), insulin, and acylated ghrelin concentrations. Crosscorrelation analysis revealed an offset ranging between 30 and 42 min between the maximum of a feed intake event and the lowest level of postprandial net fat oxidation (FOX net ) and the maximum level of postprandial net carbohydrate oxidation (COX net ), respectively. During the AL period, FOX net did not increase above −0.2 g/min, whereas COX net did not decrease below 6 g/min before the start of the next feed intake event. A strong inverse cross-correlation was obtained between COX net and plasma glucose concentration. Direct cross-correlations were observed between COXnet and insulin, between heat production and BHBA, between insulin and glucose, and between BHBA and ghrelin. We found no cross-correlation between FOX net and NEFA. During RE, FOX net increased with an exponential slope, exceeded the threshold of −0.2 g/min as indicated by increasing plasma NEFA concentrations, and approached a maximum rate of 0.1 g/min, whereas COX net decayed in an exponential manner, approaching a minimal COX net rate of about 2.5 g/min in all cows. Our novel findings suggest that, in late-lactating cows, postprandial increases in metabolic oxidative processes seem to signal suppression of feed intake, whereas preprandially an accelerated FOX net rate and a decelerated COX net rate initiate feed intake.

Effects of colostrum instead of formula feeding for the first 2 days postnatum on whole-body energy metabolism and its endocrine control in neonatal calves

“…Carbohydrate oxidation increased and FOX decreased postprandially, but FOX increased at the end of the feeding intervals (i.e., before subsequent feed intake) in both groups. This pattern of substrate oxidation relative to feed intake is known from mice (Flatt, 1991) and has also been described in dairy cows (Derno et al, 2013), and it resulted in an increase in the RQ after feed intake and lowest RQ at the end of the feeding interval. The mean RQ increased from d 2 and 3 to d 7 and 8, indicating that calves of both groups utilize more carbohydrates and less fat at the end of the first week of life.…”

“…The respiratory quotient (RQ) was defined as the quotient between the CO 2 production and the O 2 consumption of calves. Heat production, COX, and FOX were calculated using methods described by Derno et al (2013). Additionally, an infrared sensor (IS 120; Steinel, Herzbrock-Klarholz, Germany) that was installed in the chamber allowed for registration of the physical activity (standing, lying) of the calves.…”

Metabolic load in dairy cows kept in herbage‐based feeding systems and suitability of potential markers for compromised well‐being

“…In particular during early lactation, when plasma glucose concentration and rate of gluconeogenesis are low (Hammon et al., ; Aschenbach et al., ), an additional depression of gluconeogenesis by BHBA as shown for mid‐lactating dairy cows might be assumed and is undesirable. Furthermore, elevated concentrations of circulating ketone bodies were shown to depress feed intake (Laeger et al., , ; Derno et al., ) and reproductive performance (Castro et al., ). However, high‐yielding cows without supplementation of concentrate showed already a reduced DMI and a more negative EB compared to cows fed with additional concentrate.…”

Endogenous and dietary lipids influencing feed intake and energy metabolism of periparturient dairy cows

“…Plasma acyl ghrelin concentrations increase with increased time of feed deprivation of dairy cows [47,49] but also after ingestion of a diet supplemented with calcium salts of long-chain fatty acids as compared with a nonsupplemented diet [50]. On the other hand, plasma ghrelin concentrations were depressed immediately before postruminal infusion of soybean oil although they were not affected during the postprandial period [51].…”