Effects of different sources and levels of copper on lipid metabolism in Merino × Texel lambs.

The study was conducted with 40 lambs Merino × Texel in order to determine the effects of 10 or 30 mg of Cu/kg DM of copper sulphate and copper-methionine on the lipid and cholesterol metabolism. The lambs were randomly distributed into 5 treatments, with 8 animals each. The treatments were: control, without cooper additions; 10 or 30 mg of Cu/kg DM in the form of copper sulphate; 10 or 30 mg of Cu/kg DM in the form of copper-methionine. The hepatic concentration of copper was higher in lambs supplemented with copper. Total cholesterol, HDL cholesterol, LDL cholesterol and triglycerides in the serum, as well as the SFTU did not differ between treatments. The supplementation of copper regardless of source or level reduced the concentration of cholesterol in the LT muscle, and reduced the concentration of GSH and increased the concentration of GSSG in the liver. Additionally, there was a minimal effect on the fatty acid profile of lipid in lambs.

Effects of supplementation with two sources and two levels of copper on meat lipid oxidation, meat colour and superoxide dismutase and glutathione peroxidase enzyme activities in Nellore beef cattle.

In the present study, thirty-five Nellore bulls were used to determine the effects of two levels and two sources (organic and inorganic) of Cu supplementation on the oxidative stability of lipids, measured by the thiobarbituric acid-reactive substance (TBARS) test, meat colour and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities. The following treatments were used: (1) control (C) - basal diet without supplementation of Cu (7 mg Cu/kg DM); (2) I10 - basal diet supplemented with 10 mg Cu/kg DM in the form of copper sulphate (inorganic form); (3) I40 - basal diet supplemented with 40 mg Cu/kg DM in the form of copper sulphate; (4) O10 - basal diet supplemented with 10 mg Cu/kg DM in the form of copper proteinate (organic form); (5) O40 - basal diet supplemented with 40 mg Cu/kg DM in the form of copper proteinate. Lipid oxidation was determined in meat samples exposed to display, modified atmosphere (MA) and vacuum packaging (VC) conditions and in liver samples using the TBARS test. These samples were also evaluated for meat discolouration after exposure to air. The activities of SOD and GSH-Px enzymes were determined in liver samples. In display, MA and VC conditions, the TBARS values of samples from animals supplemented with 40 mg Cu/kg DM were lower than those of samples from control animals. There was no effect of treatment on the colour variables (L*, a*, b*). There was also no significant effect of treatment on hepatic TBARS concentrations and GSH-Px activity. Supplementation with Cu at 40 mg/kg, regardless of the source, induced higher hepatic SOD activity compared with the control treatment. In conclusion, Cu supplementation improved the oxidative stability of lipids in samples exposed to display, MA and VC conditions, demonstrating the antioxidant effect of this mineral.

Effects of dietary selenium, sulphur and copper levels on selenium concentration in the serum and liver of lamb.

Thirty-two lambs were distributed in eight treatments under 2×2×2 factorial experiment to compare the effects of two levels of selenium (0.2 to 5 mg/kg dry matter [DM]), sulphur (0.25% and 0.37%) and copper (8 and 25 mg/kg DM) levels on selenium concentration in liver and serum of lambs. A liver biopsy was done on all animals and blood samples were collected from the jugular vein prior to the beginning of the treatments. The blood was sampled every thirty days and the liver was sampled after 90 days, at the slaughter. Increasing differences were noticed during the data collection period for the serum selenium concentration, and it was found to be 0.667 mg/L in animals fed with 5 mg Se/kg DM and normal sulphur and copper concentrations in their diet. However, a three-way interaction and a reduction of selenium concentration to 0.483 mg/L was verified when increasing copper and sulphur concentration levels to 25 ppm and 0.37% respectively. The liver selenium concentration was also high for diets containing higher selenium concentrations, but the antagonist effect with the increased copper and sulphur levels remained, due to interactions between these minerals. Therefore, for regions where selenium is scarce, increasing its concentration in animal diets can be an interesting option. For regions with higher levels of selenium, the antagonistic effect of interaction between these three minerals should be used by increasing copper and sulphur dietary concentrations, thus preventing possible selenium poisoning.

Effects of copper and selenium supplementation on performance and lipid metabolism in confined brangus bulls.

Twenty-eight Brangus cattle were used to determine the effect of copper and selenium supplementation on performance, feed efficiency, composition of fatty acids in Longissimus dorsi (LD) muscle, and cholesterol concentration in serum and in LD muscle and enzymes activities, reduced glutathione (GSH) and oxidized glutathione (GSSG). The treatments were: i) Control, without copper (Cu) and selenium (Se) supplementation; ii) Se, 2 mg Se/kg of dry matter such as sodium selenite; iii) Cu, 40 mg Cu/kg of dry matter such as copper sulfate; iv) Se/Cu, 2 mg Se/kg of dry matter such as sodium selenite and 40 mg Cu/kg of dry matter such as copper sulfate. LD muscle fatty acid composition was not influenced by the treatments (p>0.05). The serum concentration of cholesterol was not influenced by the treatments (p>0.05), however, the concentration of cholesterol in LD was lower in cattle supplemented with copper and selenium (p<0.05). Oxidized glutathione and reduced glutathione increased (p<0.05) with Cu, Se and Se/Cu supplementation. The supplementation of copper (40 mg/kg DM) and selenium (2 mg/kg DM) altered the metabolism of lipids in confined Brangus cattle, through a decrease in cholesterol deposition in the LD, possibly by changing the ratio between reduced glutathione/oxidized glutathione. Copper and selenium supplementation improved animal performance and feed efficiency (p<0.05) when compared to the control group, providing advantages in the production system, while also benefiting consumers by reducing cholesterol concentration in the meat.

Effect of supplementation of two sources and two levels of copper on lipid metabolism in Nellore beef cattle.

UNLABELLED: This study was conducted with 35 Nellore beef cattle to determine the effect of supplementation of two levels and two copper sources (organic and inorganic) on metabolism of lipids and cholesterol of meat. The five treatments used were: CONTROL: without copper supplementation, I10 or I40: 10 or 40 mg/kg DM (as Cu sulfate), O10 or O40: 10 or 40 mg/kg DM (as Cu proteinate). In general, the copper supplementation changed the fatty acid profile of meat (p<0.05), with a higher proportion of unsaturated fatty acids and reduction of saturated fatty acids. There was no effect of supplementation on blood cholesterol and triglycerides, however; in general, there was a reduction in cholesterol concentration in the L. dorsi (p<0.05) compared to the control treatment through the reduction (p<0.05) in the concentrations of GSH and GSH/GSSG ratio. The Cu supplementation did have an influence on metabolism of lipids. The production of healthier meat is beneficial to public health by reducing the risk of cardiovascular disease.

Balanço cátion-aniônico da dieta na composição do leite / Dietary cation anion balance on milk composition

Foram utilizadas oito vacas Holandesas em lactação, distribuídas em um quadrado latino (4x4), replicado, num experimento conduzido durante o verão, por um período de 72 dias. O objetivo deste trabalho foi estudar quatro níveis de dietas catiônicas sobre a composição e as propriedades físico-químicas do leite em vacas após o pico de lactação. Para a manipulação do balanço cátion-aniônico da dieta (BCAD), foram adicionadas diferentes concentrações de bicarbonato de sódio nas dietas, obtendo-se os seguintes tratamentos: +150, +250, +400 e +500mEq kg-1 MS. Não houve diferença significativa para as variáveis: porcentagem de gordura, densidade e índice crioscópico do leite. O pH do leite aumentou linearmente e a acidez apresentou resposta cúbica com o aumento do BCAD.

Eight lactating Holsteins cows were distributed in a 4x4 replicated Latin square in the summer for 72 days. The objective of this research was to study the effect of four levels of cationic diets on the composition and physic-chemistries parameters of milk in cows after the lactation peak. For dietary cation anion balance manipulation, different concentrations of the sodium bicarbonate were added in the diets and the following treatments were obtainned: +150, +250, +400 e +500mEq kg-1 DM. The diets did not affect fat percentage and variables, density and crioscopic indice in the milk. Milk pH increased linearly and acidity decreased cubically with increased of dietary CAB.

Balanco cátion-aniônico da dieta no metabolismo de cálcio em ovinos / Dietary cation anion balance on calcium metabolism in sheep

O objetivo deste trabalho foi estudar o efeito do balanco cátion-aniônico da dieta (BCAD) no balanco e concentracão sérica de cálcio em ovinos da raca Santa Inês. O delineamento experimental foi em blocos para controlar o efeito do peso inicial dos animais. Foram utilizados cinco tratamentos com níveis crescentes de BCAD (-160, -40, 140, 250 e 500mEq/kg de matéria seca) com cinco repeticões em 25 animais. O BCAD influencia o metabolismo de cálcio em ovinos machos da raca Santa Inês. Com a diminuicão do BCAD o cálcio sérico aumentou. Dietas aniônicas aumentaram a excrecão urinária de cálcio, entretanto a retencão não foi afetada.