Nematodes and nutrient partitioning

2003 ◽  
Vol 43 (12) ◽  
pp. 1419 ◽  
Author(s):  
N. C. Roy ◽  
E. N. Bermingham ◽  
I. A. Sutherland ◽  
W. C. McNabb
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Gastrointestinal Tract ◽  
Parasitic Infection ◽  
Nitrogen Retention ◽  
Gastrointestinal Nematodes ◽  
Metabolic Effects ◽  
Protein Loss ◽  
Nutrient Utilisation ◽  
Amino Acid Utilisation

Subclinical infection of sheep with gastrointestinal nematodes results in the diversion of nutrients from growth and development towards the repair of damaged intestinal tissues and to sustain the metabolic shifts (nutritional, hormonal and immune) occuring in tissues affected by the parasites. These metabolic effects include decreased nitrogen retention; increased amino acid utilisation and oxidation in the gastrointestinal tract; increased endogenous protein loss and altered protein synthesis in the gastrointestinal tract; increased amino acid utilisation and protein synthesis in the liver and activation of the immune system. These observations strongly suggest that there is competition between the key tissues involved in parasitism and that metabolic decisions are made resulting in the re-prioritisation of nutrient utilisation between the tissues in this inter-organ system. Nutritional status of the host can influence the pathogenesis of parasitic infection and well-nourished animals generally withstand parasitism better than those less adequately fed. Recent studies have focused on the effect of restricting intake on the acquisition of immunity in sheep selected either for resistance or susceptibility to nematodes. The major outcome of these studies was the increase of peripheral eosinophil counts in resistant animals infected with Trichostrongylus colubriformis when fed on an ad libitum diet compared with similar animals fed the same diet at a maintenance level. This was inversely correlated to the numbers of adult parasites recovered. Intake seems to be the primary determinant of the expression of immunity in sheep selected for resistance against nematodes.

Effects on growth rate and utilisation of amino acids in weaner pigs fed diets containing whole proteins and free amino acids in combination with different energy sources

1998 ◽  
Vol 49 (1) ◽  
pp. 127 ◽  
Author(s):  
D. J. Farrell ◽  
D. I. Officer ◽  
E. S. Batterham
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Wheat Starch ◽  
Protein Source ◽  
Energy Sources ◽  
Nutrient Utilisation ◽  
Amino Acid Utilisation

This experiment was designed to determine the effects of 3 protein and 3 energy (carbohydrate) sources on the growth rate of weaner piglets and their eciency of nutrient utilisation. All 3 energy sources and 2 of the protein sources [casein plus free amino acids (casein), free amino acids alone (FAA)] were chosen because they were suitable for studies measuring amino acid utilisation. The third protein source, based predominantly on peptide protein, was a combination casein-fish meal-soyabean meal (CFS). The combinations of carbohydrates tested were sucrose alone, sucrose plus 150 g lactose/kg, and wheat starch plus 150 g sucrose plus 150 g lactose/kg. The experiment was a randomised complete block design based on a 33 factorial arrangement with 5 blocks and 9 pigs per block. Piglets given CFS as the protein source exhibited greater (P < 0·001) weight gain than those consuming casein or FAA (494 v. 415 and 345 g/day) and deposited protein more eciently (P < 0·001) (e.g. crude protein retention/ileal-digestible protein intake, 0·65 v. 0·56 and 0·49). The apparent digestibility of nitrogen (N) and amino acids was lower for the CFS-fed piglets (0·83 and 0·88) than for those given casein (0·92 and 0·95) or FAA (0·94 and 0·96). The daily weight gains of piglets given diets containing starch, sucrose, and lactose were 9-10% lower (P < 0·05) than those consuming either sucrose or sucrose plus lactose (391 v. 433 and 430 g/day). The energy sources, however, had no effect on ileal digestibility of amino acids or empty body composition. Neither casein nor FAA diets were found to be acceptable sources of amino acids for studies on amino acid utilisation. Sucrose and sucrose plus lactose were excellent energy sources for piglets. In contrast, wheat starch was found to be unsuitable for inclusion in synthetic weaner diets for piglets with a liveweight of 5-20 kg.

scholarly journals AN INTRACELLULAR DEFECT IN PROTEIN SYNTHESIS INDUCED BY CARBON TETRACHLORIDE

1962 ◽  
Vol 116 (1) ◽  
pp. 55-72 ◽  
Author(s):  
Edward A. Smuckler ◽  
Oscar A. Iseri ◽  
Earl P. Benditt
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Carbon Tetrachloride ◽  
Morphological Changes ◽  
Succinic Dehydrogenase ◽  
Metabolic Effects ◽  
Amino Acid Incorporation ◽  
Functional Changes ◽  
Acid Incorporation ◽  
Carbon Tetrachloride Administration

The morphological and certain metabolic effects of carbon tetrachloride intoxication were studied in the rat with emphasis on liver alterations. Morphological changes were investigated by histological and electron microscopical means. Functional changes were investigated using histochemical and amino acid incorporation, techniques. The liver constituents were examined chemically. Plasma volume alterations were measured using dye and homologous protein dilution techniques. The histological appearance of the liver of treated animals included cellular swelling, dispersal of the cytoplasmic basophilia, and necrosis. Electron micrographs showed an early (3 hours following carbon tetrachloride administration) and widespread dislocation of the ribonucleoprotein particles from the membranes of the rough endoplasmic reticulum, but no apparent alteration in the mitochondrial structure. Histochemical examination of two mitochondrial enzyme systems, α-ketoglutarate dehydrogenase and succinic dehydrogenase, revealed no alterations in activities until a later time (6 to 12 hours following carbon tetrachloride administration). ATPase showed a gross quantitative decrease in activity at 6 and 12 hours, but not earlier. There was a decreased amino acid incorporation into two liver-produced proteins, viz., albumin and fibrinogen. This decrease is not explicable on the basis of the inability of the liver to take up the amino acid, an altered dilution volume into which the amino acid or formed protein is placed, or an impaired capacity of the liver to excrete protein once formed. It is concluded that the decreased amino acid incorporation rate reflects depressed synthesis of protein by the liver. Other pathological changes in the liver, including necrosis, fatty change, and mitochondrial alterations may be dependent upon severe impairment of protein synthesis.

Protein depletion and replenishment in mice: different roles of muscle and liver

1997 ◽  
Vol 273 (6) ◽  
pp. E1158-E1167 ◽  
Author(s):  
Oscar A. Scornik ◽  
Scott K. Howell ◽  
Violeta Botbol
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Gastrointestinal Tract ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Acute Effects ◽  
Protein Loss ◽  
Protein Free Diet ◽  
Exogenous Supply

Fully grown male CD-1 mice, fed a protein-free diet for 3 days, received 1 g of starch with or without 300 mg casein by intragastric intubation. We surveyed the acute effects of these nutrients on protein synthesis in all tissues (by extrapolating to infinity the incorporation of radioactive leucine after its injection in massive doses) and protein degradation in skeletal muscle and liver (by the accumulation of bestatin-induced peptide intermediates). Muscle proteolysis was the major source of N during depletion. Compared with postabsorptive animals, starch suppressed muscle protein loss (synthesis +21%, degradation −24%, P < 0.01) and stimulated hepatic proteolysis (degradation +28%, P < 0.01). Addition of casein to the starch was anabolic in liver (synthesis +41%, degradation −33%, P < 0.01), gastrointestinal tract, pancreas, and skin (synthesis +38, +69 and +38%, respectively, P < 0.01) but had no effect on muscle. Protein turnover proved uniquely sensitive to the dietary supply of carbohydrates in muscle and to the endogenous or exogenous supply of amino acids in liver.

scholarly journals Effect of food intake on hind-limb and whole-body protein metabolism in young growing sheep: chronic studies based on arterio-venous techniques

1992 ◽  
Vol 68 (2) ◽  
pp. 389-407 ◽  
Author(s):  
Patricia M. Harris ◽  
Pat A. Skene ◽  
Vivien Buchan ◽  
E. Milne ◽  
A. G. Calder ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Protein Metabolism ◽  
Hind Limb ◽  
Live Weight ◽  
Whole Body ◽  
Acid Oxidation ◽  
Protein Loss ◽  
Body Protein ◽  
Protein Retention

Whole-body protein synthesis, estimated by the irreversible loss rate procedure, and hind-leg protein metabolism determined by arterio-venous techniques were monitored in response to three nutritional conditions (approximately 0.6, 12 and 1.8 x energy maintenance (M)) in ten wether lambs (33 kg average live weight). In all lambs and treatments measurements were based on radiolabelled phenylalanine, but the terminal procedures (five at 0.6 x M and five at 1.8 x M) also included infusion of [1-13C]leucine; this permitted comparison of amino acids catabolized (leucine) and non-metabolized (phenylalanine) by the hind-limb tissues. Whole-body protein synthesis increased with intake and the relationship with energy expenditure was slightly lower than that reported previously for pigs and cattle. The efficiency of protein retention: protein synthesis did not exceed 0.25 between the two intake extremes. Effects of intake on amino acid oxidation were similar to those observed for cattle. Hind-limb protein synthesis also increased significantly (P < 0.001) in response to intake. Estimates of protein gain, from net uptake values, indicated that the tissues made a greater proportional contribution to total protein retention above M and to protein loss below M, emphasizing the role played by muscle tissue in providing mobile protein stores. The rates of protein synthesis calculated depended on the selection of precursor (blood) metabolite, but rates based on leucine always exceeded those based on phenylalanine when precursor from the same pool was selected. The incremental efficiency of protein retained: protein synthesis was apparently unity between 0.6 and 1.2 x M but 0.3 from 1.2 to 1.8 x M. Blood flow through the iliac artery was also proportional to intake. Leucine and oxo-acid catabolism to carbon dioxide increased with intake such that the metabolic fate of the amino acid was distributed in the proportion 2:1 between protein gain and oxidation. The rates of oxidation were only 1–3% the reported capacity of the rate-limiting dehydrogenase enzyme in muscle, but sufficient enzyme activity resides in the hind-limb adipose tissue to account for such catabolism

scholarly journals Amino Acid Imbalance and Nitrogen Retention in Adult Rats

1958 ◽  
Vol 233 (6) ◽  
pp. 1505-1508
Author(s):  
Umesh S. Kumta ◽  
Alfred E. Harper ◽  
Conrad A. Elvehjem
Keyword(s):  
Amino Acid ◽  
Nitrogen Retention ◽  
Adult Rats ◽  
Amino Acid Imbalance
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