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This study aimed to test the hypothesis that maintenance energy requirement (M[E.sub.m]) can be estimated from continuous heat production measurements during a change from a near maintenance feeding level to far below maintenance for two consecutive days. The M[E.sub.m] of eight Hereford steers weighing 286 [+ or -] 5 kg (mean [+ or -] SE) was determined in a balance trial. In addition, during the 10-d collection period, the animals were kept in open-circuit respiration chambers to measure 24-h gas exchange continuously at 10-min intervals. During the balance trial, the animals were fed dried chopped grass twice daily at an estimated level of 1.2 x M[E.sub.m]. After termination of the collection period on the 11th d of the balance trial, the steers were offered 2 kg/d of wheat straw while only gas exchange was measured. Estimates of M[E.sub.m] were derived from heat production (HP) data. The analyses included values of 24-h HP, HP of the nocturnal period (0000 to 0630), HP of the nocturnal period (excluding HP caused by standing) during the grass-feeding period and 24-h HP, nocturnal HP, and nocturnal HP (excluding HP caused by standing) during the straw feeding period. The M[E.sub.m] predicted from estimates of HP measurements were 536 [+ or -] 9, 470 [+ or -] 8, 441 [+ or -] 8, 435 [+ or -] 8, 393 [+ or -], and 373 [+ or -] 9 kJ*kg of B[W.sup.0.5].[d.sup.-1], respectively, whereas M[E.sub.m] calculated from data of the balance trial were 416 [+ or -] 9 kJ-kg of B[W.sup.-0.75].[d.sup.-1]. Values predicted for nocturnal HP (excluding HP caused by standing) of grass fed animals, 24-h HP, and nocturnal HP during straw feeding did not differ significantly from M[E.sub.m]. The differences in M[E.sub.m] among animals were reflected by all estimates of HP, whereas the correlation with the 24-h HP during straw feeding reached 0.9 (P = 0.002). We conclude that the method described is adequate to determine M[E.sub.m] with a sufficient degree of accuracy. Key Words: Maintenance Energy Requirement, Heat Production, Hereford Steers, Straw Feeding

An experiment was conducted to examine the response to wheat gluten (WG)-based diets at two lysine levels in adult minipigs (23 kg BW) using the indicator AA oxidation (IAAO) approach and N balance. Twenty minipigs (n = five per group), fitted with reentrant ileoileal cannulas allowing collection of ileal effluents, were fed restrictively two WG-based diets (WG and WG + Lys; 2.7 and 6.6 g of lysine/kg, respectively) for adaptation periods of 10 and 100 d. On d 7 and 9, for pigs fed the diets for 10 d, and on d 97 and 99, for pigs fed the diets for 100 d, primed i.v. fasted/fed tracer protocols with [[sup.13]C]bicarbonate, and [[sup.13]C]leucine were performed. With the WG diet, [[sup.13]C]bicarbonate recoveries (%) were lower irrespective of the adaptation period, and higher during the fed period (fasted: WG + Lys = 82.5, and WG = 69.1; fed: WG + Lys = 90.6, and WG = 85.9; P < 0.05). Leucine oxidation rate was higher with the lower lysine intake (WG = 194.6 vs. 109.5 mg/[kg BW.d]; P < 0.05). Wheat gluten feeding resulted in a negative leucine balance independent of the adaptation period (WG = -29.1, and WG + Lys = 48.2 mg/[kg BW-d]; P < 0.05). In contrast with the IAAO method, N balance did not differ between the two lysine intakes, possibly because of an underestimation of N losses. The finding of a lower [sup.13]C bicarbonate recovery with the lower dietary lysine intake suggests that caution should be taken in using a single recovery factor for all AA oxidation studies. Key Words: [sup.13]Carbon Bicarbonate Recovery, Indicator Amino Acid Oxidation, Leucine Tracer Balance, Minipigs, Nitrogen Balance, Wheat Gluten

The still open question, whether or not feeding of fresh or ensiled roughage compared with dried roughage effects different methane emissions, was clarified experimentally. In respiration trials with sheep methane emission amounted to 24.4 g (fresh), 24.0 g (ensiled) and 24.1 g (dried) per kg dry matter intake. Consequently the methane emission determined with dried roughages is applicable to fresh and ensiled roughages. The emissions measured in sheep correspond to 24.8 g methane in cows with a milk performance of 4000 kg per cow and year. Therefore the results estimated in sheep can valued as confirmation of results investigated in cattle in dependence on their milk production. [ABSTRACT FROM AUTHOR]

Dietary energetic impact on oxidative stress is incompletely understood. Therefore, effects of diets on oxidative stress were studied using a crossover block design. In Expt 1, intake of metabolizable energy (ME) was restricted or ad libitum. In Expt 2, isoenergetic and isonitrogenic diets were fed, replacing carbohydrate energy by energy of fatty acids. Circulatory lipohydroperoxides (LOOH), markers of acute oxidative stress, were expressed absolutely and in terms of cholesterol or TAG levels. In Expt 1, plasma (jugularis vein) LOOH was assayed in combination with whole-body oxidative metabolism using gas exchange and heart rate (HR) during feeding periods and at rest. In Expt 2, LOOH was assayed in plasma from portal and a large udder vein and a mesenteric artery. In Expt 1, intake increased VO2, HR and LOOH following overnight fast with higher values (P??

BACKGROUND & AIMS: alpha-Ketoglutarate (AKG) has been suggested to play a particular role as an oxidative fuel for the gut, and thus may have a sparing function for fuels such as glutamate and aspartate. Using the pig model we aimed to quantify how the route of administration (intravenous, i.v.; intragastric, i.g.; intraduodenal, i.d.) affects AKG utilization, whole body energy expenditure (EE) and nutrient oxidation. METHODS: Pigs (15kg) were supplied with a complete nutrient solution (NS) via catheters. To explore the metabolic effects of AKG, 1.0g AKG kgBW(-1)d(-1) was infused simultaneously with the NS using either the i.d., i.v. or i.g. route. [1-(13)C]AKG (15mg kgBW(-1)) was infused i.d., i.v. or i.g., respectively, for 3h. AKG utilization (AKG UTIL) was estimated as AKG UTIL=100-(13)C recovery (% of (13)C dose). (13)C recovery was calculated from the (13)C enrichment in breath CO(2) and the whole-body CO(2) production. RESULTS: AKG infusion and NS via the i.d. route resulted in a reduced AKG UTIL (40.1+/-6.7) as compared to the i.v. route (62.9+/-2.4, P<0.001) and i.g. route (62.3+/-1.6, P<0.001). The total EE was lower with the i.d. route of AKG and NS (745+/-68kJkgBW(-0.62)d(-1)) as compared to the i.v. route (965+/-54kJkgBW(-0.62)d(-1), P<0.005) and i.g. route (918+/-43kJkgBW(-0.62)d(-1), P<0.005). Carbohydrate oxidation was increased with the i.d. route (38.2g+/-3.4kgBW(-0.62)d(-1)) as compared to the i.v. route (27.8+/-2.9gkgBW(-0.62)d(-1), P<0.08) and i.g. route (23.9+/-8.5gkgBW(-0.62)d(-1), P<0.05). Fat oxidation was decreased (2.1+/-1.9gkgBW(-0.62)d(-1); P<0.001) with the i.d. route as compared to the i.v. route (11.5+/-1.4gkgBW(-0.62)d(-1), P<0.001) and i.g. route (11.9+/-3.1gkgBW(-0.62)d(-1), P<0.001). CONCLUSIONS: The i.d. infusion of AKG in combination with the NS affected the whole body EE and nutrient oxidation, in comparison to that obtained with the i.v. and i.g. routes. It was concluded that the i.d. administration of AKG markedly controlled the nutrient partitioning in the oxidation processes. Finally, in contrary to the observations with glutamine or glutamate, a considerable percentage of the AKG infusion was retained in the body irrespective of the route of administration. [ABSTRACT FROM AUTHOR]

Deals with a study which investigated the utilization of starch for fat deposition in humans. Material and methods; Results and discussion.

Presents information on a study which examined the metabolic rate differences among individuals of an animal population. Introduction to the energy expenditure in mammals; Materials and methods; Results and discussion.

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Copyright of Zeitschrift für Ernäehrungswissenschaft is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)