Effects of Supplementing Holstein Heifers with Dietary Melatonin during Late Gestation on Growth and Cardiovascular Measurements of their Offspring

Abstract

The objective was to examine the effects of supplementing dams with dietary melatonin during late gestation on offspring growth and cardiovascular measurements. On day 190 of gestation, heifers (n = 20) were blocked by body weight and randomly assigned to one of two dietary treatments consisting of 20 mg of dietary melatonin per day [melatonin (MEL)] or no melatonin supplementation [control (CON)]. Dietary treatments were terminated on day 262 of gestation. At birth, calves were separated from their dams with no further treatments. Calf (n = 18) blood pressure, cortisol, nitrites and total antioxidant capacity were collected on weeks 0, 1, 2, 3 and 4 of age. Calf hepatic portal blood flow and concentrations of insulin-like growth factor 1 were determined on weeks 0 and 4 of age. Calf body weight, abdominal girth, hip height and wither height increased (p < 0.05) with age. An age by treatment interaction (p < 0.01) was observed for calf body weight, which was increased at weeks 8 and 9 of age in calves born to MEL heifers compared to calves born to CON heifers. Pulse pressure, mean arterial pressure, absolute hepatic portal blood flow and blood flow relative to calf body weight were not different (p > 0.05) between treatments. A main effect of calf age (p < 0.05) was observed for concentrations of insulin-like growth factor 1, which was decreased at week 4 compared to week 0. An age by treatment interaction (p < 0.05) was observed for cortisol, which was decreased at week 2 in calves from MEL-treated dams compared to calves from CON-treated dams. Early post-natal growth was altered in offspring born to dams supplemented with dietary melatonin. This could lead to further foetal programming implications in conjunction with post-natal development.

Effect of chronic melatonin supplementation during mid to late gestation on maternal uterine artery blood flow and subsequent development of male offspring in beef cattle

“…However, at weaning and castration, bull calves born to MEL dams were heavier compared to bull calves born to CON dams. This supports previous findings of Brockus et al (2016b) where dairy calves born from MEL-treated heifers had similar birth weights and an increase in calf growth compared to calves born from CON heifers. In contrast to previous work with dairy heifers that were immediately removed from the dam and fed milk replacer (Brockus et al, 2016b), beef calves from the current study were allowed to remain with the dam until weaning.…”

“…This supports previous findings of Brockus et al (2016b) where dairy calves born from MEL-treated heifers had similar birth weights and an increase in calf growth compared to calves born from CON heifers. In contrast to previous work with dairy heifers that were immediately removed from the dam and fed milk replacer (Brockus et al, 2016b), beef calves from the current study were allowed to remain with the dam until weaning. Milk yield of the dam could contribute to the increase in body weight of the calves, which should be investigated in future studies.…”

“…Brockus et al (2016a) demonstrated that dietary melatonin supplementation to Holstein heifers during mid to late gestation increased uterine artery blood flow. Additionally, calves born from melatonin-treated heifers had an increase in calf growth compared to calves born from control heifers (Brockus et al, 2016b). While programming has been researched throughout prenatal and perinatal life, there is limited research on the postnatal development of male offspring in cattle.…”

Effect of circadian system disruption on the concentration and daily oscillations of cortisol, progesterone, melatonin, serotonin, growth hormone, and core body temperature in periparturient dairy cattle

“…Melatonin is a powerful antioxidant and plays a central role in metabolism (Amaral et al, 2014). Studies of other species found levels of MEL increased across pregnancy into the early PP and changes were postulated to function in the metabolic adaptations to these reproductive states (Tamura et al, 2008;Brockus et al, 2016). In the first study, PS cows produced more milk, whereas in the second study PS cows produced less milk.…”

Effects of Melatonin on Fetal Growth and Development of Dairy Cows

“…The uterine environment during late gestation is vital for assuring a continual delivery of sufficient oxygen and nutrients to the exponentially growing fetus [7]. Melatonin has several cardiovascular and vasodilation capabilities, which could influence blood distribution and antioxidant capacity in pregnant heifers [8]. Melatonin supplementation during pregnancy may alter uteroplacental blood flow through melatonergic receptor mediated pathways or indirectly by decreasing oxidative stress in the vascular [9,10].…”