Background/Aims:The aims of this study were to: 1) investigate the specific metabolomic effects of single macro nutrients in cold exposed rats; and 2) Using centrality analysis ascertain the correlations between these metabolomic parameter measurements.Methods:Fifty male Wistar rats were divided into 5 groups and individually housed under cold climatic conditions. Rats were either cold exposed fasted (negative control) or fed with the following commercially available single macronutrients: casein, POLYCOSE® and safflower oil; the positive control diets included all macronutrients. Samples from the plasma, liver and pancreas were collected and 33 different parameters were determined.Results:The primary correlation found between pancreatic hormones and the variables as measured, showed significant positive connections between centrality network node members. Heatmap analysis showed that the macronutrients fed have very differing effects on the metabolomics measured,i.e.casein has a high Heatmap Index on plasma corticosterone while POLYCOSE® and fat had a minimal impact.Conclusion:The cold exposed fasted animal model, in which nutrient catabolism is near maximal, serves as a useful “in vivo” tool for studying the relationships among the nutrients, hormones and digestive enzymes under cold stress conditions; feed intake, liver glucose, and small intestinal amylase hold a high position in centrality mapping and are highly imbedded in the metabolomic networks. For example, this model shed light on the relations amoung hormone and enzyme contents of duodenal pancreas, gastric+splenic pancreas and enzyme activities in small intestinal contents. These findings can be applied to optimizing feeding of animals under cold stress.

Etude comparative, in vitro, de la cinetique de degradation d'amidon de mais ou de riz par de l'amylase salivaire humaine ou de l'amylase pancreatique de porc en presence de differentes concentrations de cafeine. On ne constate pas d'interaction precise

Orchardgrass (Dactylis glomerata) and Kenny, a fescue-rye hybrid (Festuca arundinacea crossed with Secale cerale), at two levels of nitrogen fertilization [0 (nonfertilized) and 84 kg/ha (fertilized)] and two stages of maturity [April 23 (early) and June 5 (late) harvests] were fed to 16 wether lambs in two metabolism trials. Magnesium intakes (g/day) based on 1,000 g air dry feed consumption were: 1) orchardgrass 1.90 (early nonfertilized), 1.73 (early fertilized), 1.72 (late nonfertilized), 1.66 (late fertilized); 2) Kenhy 1.99 (early nonfertilized), 1.80 (early fertilized), 2.28 (late non-fertilized) and 2.22 (late fertilized). Magnesium retention was significantly less (P<.01) with early stages of maturity. Fertilization lowered magnesium intake, percentage apparent absorption (P<.01) and magnesium balance (P<.01). There was no significant difference in Mg balance due to forage species. Early stage of maturity of these two forages gave higher (P<.01) nitrogen and lower (P<.01) potassium retentions. There were no significant differences in potassium and nitrogen balances due to forage species or levels of fertilization. Sheep fed orchardgrass had a higher calcium retention than sheep fed Kenhy (P<.01). Chlorophyll content of the forages was measured, but less than 4% of plant magnesium was extracted with the chlorophyll. This binding was not considered an important factor in forage magnesium availability.

Sixty-five lambs were used in a growth, blood composition and digestive tract contents nitrogen fractionation study. Fifty lambs were used to compare five rations in which supplemental nitrogen was furnished by either CGM or urea. The rations contained either 0, 10, 20, 30, of 40% of the total nitrogen from urea with the remaining portion of the supplementary nitrogen being supplied by CGM. A faster rate of gain was obtained from the rations in which 100 or 75% of the supplemental nitrogen was furnished by CGM, lending support to the idea that some preformed supplementary dietary protein is desirable for growth. Plasma amino acid levels varied considerably among treatments with trends toward lower levels of total essential amino acids in lambs fed the higher levels of dietary urea. High levels of dietary CGM tended to give increased plasma leucine while high levels of dietary urea resulted in increased plasma lysine. Fifteen lambs were fed the same five rations and sacrified after a 21-day feeding period. Digesta samples were taken from the reticulo-rumen, omasum, abomasum, duodenum, jejunum, ileum, cecum and colom. As the percentage of urea in the diet increased there was a decrease in the percentage of dietary nitrogen recovered in the rumen. Most endogenous nitrogen secretion occurred in the duodenum. Protein nitrogen decreased from the omasum to the jejunum and was accompanied by an increase in amino nitrogen in these same areas. Amino acid analyses, expressed as a molar percentage of the total, indicated that urea additions may change the percentage of certain essential amino acids in the abomasum.