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Abstract: The present study examined, at identical daily nutrient intakes, the impact of separating protein and lactose intakes across two daily meals on the metabolic and endocrine status in heavy veal calves. Calves were assigned to one of six degrees of separating protein and lactose over the two meals (termed nutrient synchrony, SYN 1–6; 6 calves/treatment). They were fed the protein-rich (P-)meal and the lactose-rich (L-)meal at 06:00 and 18:00h, respectively, or vice versa. At SYN 1, calves were fed with 50% of the daily protein and 50% of the daily lactose intake in each meal. Protein and lactose were iso-energetically exchanged between the two daily meals from SYN 1 to 6. At SYN 6, 85% of the daily protein and 20% of the daily lactose was fed in the P-meal and the remainder in the L-meal. Blood samples were collected hourly during 24h. Mean 24h glucose concentrations increased and insulin concentrations decreased from SYN 1 to 6. Postprandial 5h areas under concentration curves (AUC0–5h) of glucose increased with increasing meal lactose content. AUC0–5h of non-esterified fatty acids increased after P- and L-meals from SYN 1 to 6. Urea concentrations increased after L-meals from SYN 1 to 6, but decreased after P-meals from SYN 1 to 6. Insulin AUC0–5h decreased after L-meals and after P-meals from SYN 1 to 6. Nutrient asynchrony did not affect insulin-like growth factor-1, glucagon, growth hormone, leptin, 3,5,3′-triiodothyronine and thyroxine. In conclusion, separation of protein and lactose intake over meals inhibited insulin responses to a lactose-rich meal in heavy veal calves despite high plasma glucose concentrations. [Copyright &y& Elsevier]

Abstract: This study hypothesized that increased feeding frequency (FF) decreases problems with glucose homeostasis seen at high feeding levels (FL) in heavy veal calves. Effects of FF and FL on hormone and metabolite concentrations were studied in 15 heavy veal calves fed once (FF1; at 12:00), twice (FF2; at 12:00 and 24:00) or four times daily (FF4; at 06:00, 12:00, 18:00 and 24:00). In period 1, all calves were fed at a low FL (FLlow; 1.5×metabolizable energy requirements for maintenance, MEm). In period 2, FF2 and FF4 calves were fed at high FL (FLhigh; 2.5×MEm), whereas FF1 calves were still fed at FLlow. Blood was sampled every 30min from 12:00 to 18:00 and postprandial integrated plasma hormone and metabolite concentrations (AUC12–18h) were calculated. Glucose AUC12–18h increased with increasing FL, but decreased with increasing FF, urea AUC12–18h increased with increasing FL, whereas non-esterified fatty acid AUC12–18h were unaffected by FL and FF. Insulin AUC12–18h decreased with increasing FF and decreasing FL. Glucagon AUC12–18h increased with increasing FL and FF. Growth hormone AUC12–18h decreased, whereas insulin-like growth factor-1 and leptin AUC12–18h increased with increasing FL. Mean thyroxine and 3,5,3′-triiodothyronine concentrations were modified by FF and FL. There were no FF×FL interactions, except for plasma glucose. In conclusion, postprandial hormone and metabolite responses were differentially affected by FF and (or) FL. Glucose and insulin concentrations were maximally increased at high FL and low FF. Hyperglycemia, glucosuria and excessive insulinemia were prevented by increasing FF and decreasing FL. [Copyright &y& Elsevier]