Effect of feed restriction on plasma concentration of hormones and metabolites in steers fed grass silage

Abstract

. 2001. Effect of feed restriction on plasma concentration of hormones and metabolites in steers fed grass silage. Can. J. Anim. Sci. 81: 553-561. Plasma concentrations of hormones and metabolites were measured in growing steers to establish their relation with degree of feed restriction. Sixty medium frame beef steers (259 ± 29 kg) were divided in groups of five and fed during 3 mo either timothy (T) or bromegrass (B) harvested at stem elongation of the first cut or at boot stage of the aftermath. Forages were fed at one of three levels of intake: ad libitum (FF), 80% of FF, or 65% of FF. Plasma concentrations of growth hormone (GH), insulin, glucagon, insulin-like growth factor-1 (IGF-1), glucose and nonesterfied fatty acids (NEFA) were measured on day 1 and day 78 before the morning meal. The effect of a meal on GH, insulin, glucagon, IGF-1, glucose and NEFA concentrations was also determined in 24 steers sampled from 3 h before to 3 h after a meal. Severity of feed restriction resulted in a linear decrease (P < 0.05) of plasma glucagon (0.139, 0.130, 0.121 ± 0.005 ng mL -1 ) and IGF-1 (109, 98, 84 ± 7 ng mL -1 ). Insulin concentration tended to be affected quadratically (0.37, 0.35, 0.27 ± 0.04 ng mL -1 for FF, 80% of FF and 65% of FF, respectively, P < 0.10). Ingestion of a meal resulted in a decrease (P < 0.05) of GH, NEFA and glucose, and an increase of insulin concentrations (P < 0.05). There was a positive correlation (r = 0.53, P < 0.05) between IGF-1 and average daily gain, and lipid percentage of carcasses suggesting that IGF-1 is related to growth rate and fat accumulation in growing steers. kg) ont été divisés en groupes de cinq et alimentés pour une période de trois mois avec de la fléole ou du brome récoltés au stade d'élongation de la première coupe ou au stade bouton du regain. Les fourrages ont été servis à un des trois niveaux suivants: à volonté (AV), 80% de AV, ou 65% de AV. Les concentrations plasmatiques de l'hormone de croissance (HC), de l'insuline, du glucagon, du IGF-1, du glucose et des acides gras non estérifiés (AGNE) ont été déterminés aux jours 1 et 78 avant le repas matinal. L'effet de l'ingestion du repas sur les niveaux plasmatiques de l'HC, de l'insuline, du glucagon, de l'IGF-1, du glucose et des AGNE a été aussi déterminé chez 24 bouvillons échantillonnés de 3 h avant à 3 h après un repas. La sévérité de la restiction alimentaire a causé une diminution linéaire (P < 0,05) de la concentration plasmatique de glucagon (0,139; 0,130; 0,121 ± 0,005 ng mL -1 ) et de l'IGF-1 (109; 98; 84 ± 7 ng mL -1 ) et tendait à affecter de façon quadratique la concentration de l'insuline (0,37; 0,35; 0,27 ± 0,04 ng mL -1 pour les groupes à AV, 80% de AV et 65% de AV, respectivement, P < 0,10). L'ingestion du repas a causé une diminution (P < 0,05) de la concentration de l'HC, des AGNE et du glucose tandis que la concentration de l'insuline augmentait (P < 0,05). Les concentrations d'IGF-1 était corrélée (r = 0,53, P < 0,05) avec le gain moyen quotidien et la composition lipidique des carcasses...

Evaluation of the association between plasma glucose-dependent insulinotropic polypeptide, respiratory quotient, and intramuscular fat deposition in feedlot cattle fed different levels of dry matter intake

“…However, the DMI after 2 h of feed offered, on the days that gas exchange and blood samples were taken, was greater ( P < 0.01; Table 2 ) for the RI steers compared with the AI steers. Similar differences in ADG due to diet restrictions have been reported previously ( Hicks et al, 1990 ; Holt et al, 2000 ; Ouellet et al, 2001 ; Prezotto et al, 2017 ). The differences in DMI 2 h after feeding, where RI steers eat more than the ad libitum feed steers, might be due to changes in eating behavior.…”

“…Steers on AI have greater final BW ( P = 0.02; Table 2 ). This greater final BW in AI steers may be due to the increase in DMI during the finishing period and it is similar to what was observed previously with growing cattle fed a grass silage diet that had increasing final BW with increasing intake level (ad libitum vs. 80% and 65% restriction; Ouellet et al, 2001 ). Similarly, growing cattle fed ad libitum grass silage had greater final BW than restricted-fed calves (80%) ( Prezotto et al, 2017 ).…”

Metabolic adaptation and hormonal regulation in young rabbit does during long-term caloric restriction and subsequent compensatory growth

“…Glucose, the body's major energy source, was lower in R rabbits throughout most of the restriction and the recovery phase due to their lower amount of food intake compared with the AL rabbits. That decreased nutrient intake reduces glucose concentration has also been reported in other species subjected to low planes of nutrition (Booth et al, 1996;Ouellet et al, 2001).…”

The effect of long term under- and over-feeding of sheep on milk and plasma fatty acid profiles and on insulin and leptin concentrations

“…There is a direct relationship between insulin concentrations and feeding level as insulin responds directly to nutrients absorbed from the gastrointestinal tract (Ouellet et al 2001). In this study significantly higher plasma insulin concentrations were observed in overfed, compared with underfed sheep (Table 6) Scaramuzzi et al (2006) and by Henry et al (2004) after short-term fasting (32 h).…”

“…Nutrition has a significant impact on numerous metabolic functions including hormones production. There is a direct relationship between insulin concentrations and feeding level as insulin responds directly to nutrients absorbed from the gastrointestinal tract (Ouellet et al 2001). In this study significantly higher plasma insulin concentrations were observed in overfed, compared with underfed sheep (Table 6).…”