CP Reduction Research Articles

Níveis de proteína bruta e suplementação de aminoácidos em dietas para leitoas mantidas em ambiente de alta temperatura dos 60 aos 100 kg

Este experimento foi conduzido para determinar o nível de proteína bruta (PB) com suplementação de aminoácidos em dietas para leitoas mantidas em ambiente de alta temperatura na fase de terminação. Foram utilizadas 35 leitoas mestiças (Landrace <FONT FACE=Symbol>´</FONT> Large White) com peso médio inicial de 60,3 kg, em delineamento inteiramente ao acaso, com cinco dietas (17,3; 16,0; 14,7; 13,4 e 12,1% PB), sete repetições e um animal por unidade experimental. As dietas experimentais foram fornecidas à vontade até o final do experimento, quando os animais atingiram 100,3 kg de PV. A temperatura média no interior da sala foi mantida em 30,6ºC, com umidade relativa de 71% e índice de temperatura de globo e umidade de 81. Não houve efeito da redução do nível de PB da dieta sobre as características de desempenho estudadas (ganho de peso, consumo de ração e conversão alimentar). As características da carcaça (comprimento da carcaça, área de olho-de-lombo, espessura de toucinho e rendimentos da carcaça, de carne magra, de gordura e de pernil) também não foram influenciadas pela redução dos níveis de PB da dieta. Os níveis de PB e a suplementação de aminoácidos na dieta influenciaram os pesos absoluto e relativo do intestino; os menores valores foram observados nos animais alimentados com a dieta com menor nível de PB (12,1%). A redução do nível de PB da dieta de 17,3 para 12,1% não prejudica o desempenho de leitoas mantidas em ambiente de alta temperatura na fase dos 60 aos 100 kg, desde que as dietas sejam devidamente suplementadas com os aminoácidos essenciais limitantes.

Performance responses and indicators of gastrointestinal health in early-weaned pigs fed low-protein amino acid-supplemented diets1

The effects of low-protein AA-supplemented diets on piglet performance, visceral organ mass, incidence of diarrhea, intestinal microbial population, and fermentation were studied in a 3-wk trial. After a 7-d adaptation period, 96 piglets (approximately 6.2 kg of initial BW) were assigned to 4 corn-wheat, soybean meal-based dietary treatments in a completely randomized design to give 6 replicate pens per treatment (n = 4 piglets per pen). The treatments were a control wheat-corn-soybean meal-based phase I diet containing 23% CP, or the same diet with CP reduced to 21%, 19%, or 17% and supplemented with crystalline AA to achieve equal standardized ileal digestible contents of Lys, Met plus Cys, Thr, and Trp in all diets. Diets were formulated to similar nutrient levels and provided ad libitum. Blood from all pigs was taken on d 0, 7, 14, and 21 for determining plasma urea N. Weekly feed intake, BW changes, and G:F were determined. On d 21, 2 pigs per pen were randomly selected and killed to determine small intestinal morphology, digesta pH and ammonia levels, and luminal microbial counts. Average daily feed intake, ADG, and G:F were not affected (P > 0.10) by reducing CP to 21%, but a reduction to 19% or 17% decreased ADFI (P < 0.001) and ADG (linear, P < 0.001; quadratic, P < 0.05) over the 3-wk study period. Reducing CP to 19% had no effect (P > 0.10) on G:F; however, this response criterion was decreased linearly (P < 0.001) over the 3-wk study period as dietary CP declined. Water usage was only numerically decreased (P > 0.10) with dietary CP reduction. Plasma urea N was decreased linearly (P < 0.01) with CP reduction. Reducing CP from 23 to 17% had a linear (P < 0.05) and cubic effect on stomach and liver weights, respectively. Although histological data showed some differences among diets, no distinct trend was evident. Ammonia N in ileal digesta was reduced linearly (P < 0.01) as dietary CP was decreased. With the exception of valeric acid, VFA levels in ileal digesta of piglets fed low-protein diets were generally lower (P < 0.05) compared with the control diet. Diet had no effect on intestinal microbial counts (P > 0.10). The results show that piglet performance may suffer when dietary CP is reduced by 4 or more percentage units from 23% and support the hypothesis that low-CP diets help maintain enteric health in pigs by lowering toxic microbial metabolites such as ammonia.

An anticopper antiangiogenic approach for advanced cancer in spontaneously occurring tumors using tetrathiomolybdate: A pilot study in a canine animal model

AbstractIn this pilot study, 13 dogs of various breeds and ages with a variety of advanced tumors were treated with the antiangiogenic copper complexing drug tetrathiomolybdate. Dose escalations were performed to determine the safe and effective dose in dogs. The study was designed to last for a 6‐month period for each dog entered. Dogs were examined weekly for the first 3 months and then every other week for the next 3 months. Complete blood count, serum biochemistry panel, and measurement of serum ceruloplasmin (Cp) content were conducted at each visit to monitor response to drug administration. Serum Cp was used as a surrogate marker of copper status. The owner reported toxicity at each visit. The dog was examined for physical abnormalities. Tumor measurements were completed every 2 weeks using direct measurements of the tumor with calipers in three planes or by direct measurements of the tumor using radiographic or ultrasonographic images in two planes. Tumor response was evaluated only after dogs achieved a 4‐week reduction in their serum Cp content. Tumor responses were defined as either disease stabilization or reduction in tumor volume. Nine dogs achieved Cp reduction. Of those dogs, five had no response to treatment, whereas four dogs had tumor responses after Cp reduction, characterized as either disease stabilization or reduction in tumor volume, for the remainder of the study period. There was only mild self‐limiting toxicity with use of the drug. J. Trace Elem. Exp. Med. 17:9–20, 2004. © 2004 Wiley‐Liss, Inc.

Effects of Muscle Glycogen on Performance of Repeated Sprints and Mechanisms of Fatigue

This study investigated the effect of initial muscle glycogen on performance of repeated sprints and some potential mechanisms for an effect of glycogen on fatigue. Eight subjects performed 2 cycling trials (repeated 60-s sprints) following consumption of either a high carbohydrate (HC) or a low carbohydrate (LC) diet. Muscle biopsies and blood samples were collected at baseline, following a 15% (15% fatigue) and a 30% decline in sprint performance (30% fatigue), when exercise was terminated. Baseline muscle glycogen levels [346 +/- 19 HC (SEM) vs. 222 +/- 19 mmol/kg dw LC] and total exercise time to 30% fatigue were higher following HC than LC (57.5 +/- 10.0 vs. 42.0 +/- 3.6 min; p <.05). Similar significant (p <.05) decreases over the entire exercise bout were seen in muscle glycogen (43%), creatine phosphate (CP; 35%), and sarcoplasmic reticulum (SR) Ca2+-uptake in isolated homogenized muscle (56%) for both trials (p >.05 between trials). The percentage decline in SR Ca2+-release was less for HC than LC (36% and 53%, respectively), but this was not statistically different. In summary, HC delayed fatigue during repeated sprints. As the reductions in muscle glycogen, CP, and SR function during exercise were not different by dietary treatment, these data do not support a link between whole muscle glycogen and SR function or CP reduction during repeated sprint exercise.

Oxygen exchange at Mo/V mixed oxides: A transient and [formula omitted] isotope study under technical conditions

Mo/V mixed oxides have proven themselves to be reliable for the partial oxidation of acrolein to acrylic acid. Methacrolein which is the homologue of acrolein, reacts with clearly worse selectivity and activity on this catalyst system. By means of transient investigations (TP reduction, CP reduction, CP reaction and 18 O -SSITKA) under reaction conditions, it was possible to provide a contribution towards clarifying the oxygen exchange of the Mo/V mixed oxides during the reaction of both aldehydes to the corresponding carboxylic acids. In the case of both aldehydes, an exchange of carbonyl oxygen and solid oxygen occurs on the Mo/V mixed oxide.