Feed restriction and realimentation in Holstein–Friesian bulls: II. Effect on blood pressure and systemic concentrations of metabolites and metabolic hormones1

Abstract

The objective of this study was to evaluate the endocrine response and metabolic rate in Holstein–Friesian bulls during restricted feeding and realimentation. Sixty bulls were allocated to 1 of 2 feeding regimes: 1) restricted feed allowance (RES; n = 30) or 2) ad libitum feeding (ADLIB; n = 30) for 125 d (Period 1). The bulls in both treatment groups were then offered ad libitum access to feed for a further 55 d (Period 2). Five and 4 blood samples were collected during periods 1 (n = 60) and 2 (n = 30), respectively. Plasma samples were assayed for hormones and metabolites including insulin, IGF-1, leptin, thyroid hormones, albumin, β-hydroxy butyrate (BHB), creatinine, glucose, NEFA, total protein, triglycerides, and urea. Blood pressure measurements were determined on all animals at the beginning and end of each period as an indicator of metabolic rate. During Period 1, RES bulls gained 0.6 kg/d whereas ADLIB bulls grew at 1.9 kg/d. Following realimentation in Period 2, RES bulls displayed accelerated growth, gaining 2.5 kg/d compared with 1.4 kg/d for ADLIB bulls (P < 0.001). Treatment × period interactions (P < 0.05) were evident for all plasma analytes assayed. During Period 1, RES bulls had lower concentrations of glucose and insulin, reflecting their lower feed intake. Adipose and protein tissue mobilization was evident through greater concentrations of triglycerides, NEFA, BHB, creatinine, albumin, and total protein in RES animals in Period 1. Additionally, the effect of restricted feeding on growth was apparent through lower concentrations of IGF-1. A lower metabolic rate was also apparent through lower concentrations of thyroid hormones and fewer beats per minute in RES bulls during Period 1. During the initial stage of realimentation in Period 2, IGF-1, insulin, thyroid hormones, creatinine, glucose, total protein, and triglycerides followed the same pattern as per Period 1 with divergence maintained between RES and ADLIB bulls (P < 0.05), whereas concentrations of all of these hormones and metabolites had converged between the treatment groups by the end of Period 2. During realimentation, the number of heart beats per minute was greater in RES bulls, indicating greater metabolic rate in these animals (P < 0.001). Results from the current study clearly show that feed restriction followed by realimentation affects key indices of metabolic status as well as tissue catabolism and provides an insight into the metabolic control of compensatory growth in cattle.

Effect of dietary restriction and subsequent re-alimentation on the transcriptional profile of bovine ruminal epithelium

“…Alternatively, it has been suggested that the immune response could be involved in nutrient partitioning away from non-essential activities including growth and instead towards activating tissue mobilisation and catabolism [72]. Nutrient partitioning during diet restriction has been widely reported in cattle [11, 12, 44, 73, 74]. When coupled with data from the present study these results indicate that the immune system may be contributing to this observed effect.…”

“…Both of these genes were also up-regulated in skeletal muscle tissue of cattle undergoing CG [25]. Overall these results suggest that increased cellular protein folding activity is required within the rumen papillae as part of the adaption to an increased dietary intake and is consistent with the heightened metabolic state typical of animals undergoing re-alimentation induced CG [11, 12, 44, 45]. Indeed, this may be a necessary response in order to cope with the typically elevated rate of metabolism associated with greater feed consumption [46], which appears to be a primary driver of whole animal CG [8, 11, 14].…”

“…This experiment was conducted as part of a research programme designed to examine the physiological and molecular control of CG in growing beef cattle [11, 12]. Purebred Holstein Friesian bulls (n = 60) were managed on the same commercial farm in Co. Offaly, Ireland, prior to being transferred to Teagasc Grange Beef Research Centre, Dunsany, Co. Meath, Ireland.…”

Effect of commercial tannin and a pornunça (Manihot spp.) silage‐based diet on the fatty acid profile of Saanen goats’ milk

“…The increased urine creatinine concentration as tannin was added could be linked to a likely increase in muscle catabolism to compensate for the lower dry matter intake (Keogh et al . ).…”

Effect of feed restriction and subsequent re-alimentation on hormones and genes of the somatotropic axis in cattle

“…It may be defined as a physiological process whereby an animal has the potential, following a period of restricted feed intake, to undergo accelerated growth upon re-alimentation (31). Previous investigations into the underlying biology of compensatory growth by our own group and by others have suggested greater feed intake and efficiency, reduced metabolic rate, and alterations in energy partitioning and tissue deposition to all be associated with the accelerated growth phenomenon (31,37,62,64,77,78). However, despite its potential importance to reducing the costs of beef cattle production systems, there is a dearth of knowledge in relation to the biological and in par-ticular the molecular mechanisms regulating the compensatory growth phenomenon.…”