Estimation of quantitative oxidation and fat retention from carbohydrate, protein and fat in growing pigs

Abstract

Zusammenfassung Die Oxidation von Nährstoffen und Retention von Kohlenhydraten, Protein und Fett hei wachsenden Schweinen Die Oxidation von Nährstoffen sowie deren Beitrag zur Fettretention wurde an Hand von 185 individuellen Bilanzstudien mit wachsenden Schweinen (40–100 kg Lebendgewicht) beurteilt. Der Respirationskoeffizient ohne Berücksichtigung des Proteins (RQnp) lag entweder unter oder über 1. Die beschriebene Methode basierend auf Gasaustausch sowie Kohlenstoff‐Stickstoffbilanz zur Berechnung der Oxidation von Nährstoffen und Lipogenese ist in beiden Fällen gültig (RQnp > 1 und RQnp < 1). Bei einer den Wachstumsbedarf deckenden Energiezufuhr (ME ≥ 1,2 MJ/kg0.75) ist die Oxidation von Nährstoffen im Bezug auf die Proteinretention abhängig von der Menge und Qualität des verdauten Proteins. Weiterhin besteht eine Abhängigkeit von der Menge an verdaulichen Kohlenhydraten. Die Versorgung mit Fett spielt dagegen keine Rolle. Die Oxidation von Kohlenhydraten trägt mit 85%, die von Protein mit 15% zur anfallenden Wärmeenergie bei. Eine Fettoxidation findet auch bei hohem Fettgehalt der Nahrung nicht statt. Die Lipogenese aus Kohlenhydraten stellt die Hauptquelle für die Körperfettretention dar. Da keine Fettoxidation stattfindet, wird das gesamte Nahrungsfett im Körper reteniert. Bei einer für das Wachstum zu geringen Energiezufuhr werden Nahrungsfett und Körperfett oxidiert. Um Protein für die Retention zu erhalten, ist die Oxidation von Protein vermindert. Selbst bei Mobilisierung von Körperfett und Oxidation von Nahrungsfett wird ein Teil der Kohlenhydrate und des Proteins für die Lipogenese vermutlich zum Aufbau von Strukturfett verwendet.

Effect of high dietary fat content on heat production and lipid and protein deposition in growing immunocastrated male pigs

“…The increased dietary fat after V2 additionally stimulated retention of energy in the form of fat. However, the contribution of lipogenesis to RE as fat was reduced, because additional dietary fat was deposited in carcass as such without oxidation of dietary fat and de novo synthesis (Chwalibog et al, 1992;Bruininx et al, 2011). Indeed, a lower intensity of lipogenesis from carbohydrate in pigs consuming HF diet was confirmed by a reduced respiratory quotient in the present study.…”

“…At a given stage of growth (or production), the ratio ME : DE is linearly related to dietary protein content (Noblet and Perez, 1993) and reflects the variation of N excretion in the urine with variation of LF diet = low-fat diet; HF diet = high-fat diet; IC = immunocastration; IC + growth = effect evaluated as the difference between group 1 in stage 1 and group 1 in stage 2; Diet = effect evaluated as the difference between group 1 and group 2 in stage 2; ME = metabolizable energy; NE = net energy; HP = heat production; corrected activity HP = activity of HP corrected for the difference in physical activity among animals (assuming a constant 8.7% activity HP:ME through experiment) according to Labussière et al (2011); DM = dry matter. For diet composition see Oxidation of nutrients and their contribution to lipid deposition were calculated according to Chwalibog et al (1992).…”

“…Energy retained as LD was calculated as the difference between total RE and RE as protein; LD (g) calculation assumed that the energy content of LD equals 39.7 kJ/g. Oxidation of nutrients and their contribution to LD were calculated according to Chwalibog et al (1992) from N excreted in urine (oxidation of proteins) or from gas exchange measurements (oxidation of carbohydrate and fat). The values obtained for the oxidation of carbohydrates and fat were interpreted as 'apparent values', corrected for apparent oxidation of lipids, because the respiratory quotient unrelated to protein oxidation was above 1.0, which caused oxidation of fat to be negative.…”

LH release in mink (Mustela vison). Pattern of the LH surge and effect of metabolic status

“…Although OXP in reality denotes deamination of protein rather than true oxidation [46], it reflects the level of the nutrient which is not used in protein metabolism but as a metabolic fuel. The values found here can be compared with about 15% OXP/HE in growing pigs [13] and demonstrate the profound importance of protein as an energy source in the mink. Period effects were significant for thyroid hormones and IGF-1 and with insulin there was only a tendency for them; concentrations decreased during restriction and increased during refeeding.…”

“…Quantitative oxidation of protein (OXP), fat (OXF) and carbohydrate (OXCHO) was calculated based on gas exchange measurements and UN as described and validated for pigs by [13]:…”