Urinary excretion of purine derivatives and nitrogen compounds of zebu cattle grazing

O presente trabalho foi desenvolvido com os objetivos de avaliar a excreção dos derivados de purinas e de compostos nitrogenados em zebuínos em pastejo, em diferentes dias e períodos dentro de dias. O experimento foi conduzido no setor de gado de corte da Universidade Federal de Viçosa/MG, utilizando-se cinco novilhas Nelore com peso corporal médio de 300 ± 15kg e 20 meses de idade, distribuídas em quadrado latino 5x5. Os tratamentos experimentais foram definidos para representar aqueles normalmente utilizados na época seca do ano, sendo eles: controle (sal mineral), concentrado com 20,31% de proteína bruta (PB) com base na matéria seca (MS) sendo oferecido (OF) em nível de 0,5 e 1% do peso corporal em jejum (PCJ), OF5 e OF10, respectivamente; e dois concentrados autorreguladores (AR) de consumo, um contendo 69,38% PB com base na MS (20% de ureia e 20% de sal) ofertado ad libitun (AR70) e outro concentrado contendo 39,73% PB com base na MS sendo ofertado ad libitum (AR40). Os períodos experimentais possuíram 18 dias, sendo o dia um para realização de jejum de 14 horas para pesagem e ajuste das quantidades fornecidas, 12 para adaptação dos animais às dietas experimentais e cinco para a coleta total de urina e amostral de fezes, nos horários das 0h00 às 4h00, 4h00 às 8h00, 8h00 às 12h00, 12h00 às 16h00, 16h00 às 20h00 e 20h00 às 24h00. Para a coleta total de urina utilizou-se sonda de Folley no26, acoplada a mangueira de polietileno que conduziu a urina até uma bolsa coletora de urina por sistema fechado, que foi esvaziada a cada duas horas no intervalo das 8h00 às 20h00, e a cada quatro horas no intervalo das 20h00 às 8h00, sendo posteriormente homogeneizadas e resfriadas. A amostragem da urina coletada foi realizada a cada 4 horas, medindo-se o volume e retirando-se duas amostras, uma diluída com solução H2SO4 0,036N e não diluida. Para determinação da excreção fecal, utilizou-se o dioxido de titânio, fornecido na quantidade total diária de 15g, entre os dias 9 e 18 de cada período. Para estimativa do consumo de pasto, utilizou-se a fibra indigestível em detergente neutro (FDNi), como indicador interno. Realizou-se coleta de pasto pela técnica do quadrado para determinação da matéria seca potencialmente digestível (MSpd) no terceiro dia de cada período experimental, e nos dias 14o e 18o realizou-se simulação de pastejo para estimar os consumos dos constituintes das dietas. Nas amostras de urina foram determinadas as concentrações de creatinina, nitrogênio total, ureia, acido úrico e alantoína. Para análise estatística utilizou-se o programa estatístico Proc Mixed do SAS. O consumo de MS foi superior (P0,05) do tratamento OF5. O consumo de PB aumentou com a suplementação (P0,05) e apresentaram média de 23,03 ± 0,30 mg/kgPC. As relações urinárias da alantoína (Al) e do ácido úrico (AU) com a creatinina não foram influenciadas (P>0,05) pelos tratamentos, dias de coleta e horários de coleta. As relações nitrogênio total:creatinina e nitrogênio ureico:creatinina na urina apresentaram interação (P0,05), e tratamento controle, que apresentou o menor BN. A produção de compostos nitrogenados microbianos não foi alterada (P>0,05) pelos tratamentos. A eficiência microbiana, em gPBmic/kgMOD e gPBmic/kgNDT foi afetada (P0.05) treatment OF5. The CP intake increased by supplementation (P0.05) and had a mean of 23.03 ± 0.30 mg / kgPC. Urinary relations of allantoin (Al) and uric acid (UA) with creatinine were not affected (P>0.05) by treatments, collection days and times of collection. The total nitrogen relations:creatinine and urea nitrogen:creatinine in urine showed interaction (P 0.05), and control treatment, with the lowest NB. The production of microbial N was not affected (P>0.05) by treatments. The microbial efficiency gPBmic/kgMOD and gPBmic/kgNDT was affected (P<0.05) by supplementation, being higher (P<0.05) for OF5, OF10 and SR70 treatments, which did not differ. The control and OF5, treatments had the lowest values were similar. The lack of effect of day and the collection period on allantoin and uric acid compared with creatinine has wide practical application, enabling use spot urine sample to calculate the excretion of purine derivatives at any time of day or night, and consequently the microbial production. Depending on the variations observed for total nitrogen and urea nitrogen relations with creatinine over 24 hours is not recommended the use of a single spot urine sample for determination of these nitrogen compounds.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Creatinine recovery from bovine urine under the effect of different times and temperatures of storage.

Creatinine is a urinary marker used widely in ruminant's experimental trials. However, despite its great importance no data were found in the literature about the best way to store bovine urine samples. In the sheep urine, was observed an increase in the urinary concentration of creatinine when it was stored acidified (pH 2.5 to 3.5) at a temperature of 28 to 39 °C for 150 days of storage. Nevertheless, urine should be stored acidified (pH below 3) to avoid purine derivative degradation, So, aimed to evaluate creatinine recovery in bovine urine as a function of storage time and temperature. A total of 25 animals' urine (10 Nellore cattle and 15 Holstein cattle) were collected. The urine (40 mL) was diluted in 160 mL of distilled water and its pH was corrected to a value lower than 3 using sulfuric acid drops. A sample of the diluted urine was analyzed to obtain the creatinine concentration reference value on the collection day. The remaining urine was fractionated and preserved at room temperature, cooled (4 °C) or frozen (-20 °C and -40 °C). In the urine of five Holstein cattle was added creatine solutions (20, 40 and 60 mg/dL) to evaluate the creatine to creatinine conservation. These urine samples were analyzed on different days after collection (1, 3, 7, 15, 30 and 45 days). The urine without any added creatine was analyzed on Days 1, 3, 7, 10, 15, 30, 45, 60, 90, 120, and 150 of storage. The addition of creatine in the urine caused an increase in the creatinine concentration (P 0.05). However, creatinine recovery was constant (P > 0.05) until day 15 of storage, regardless of the temperature used, when creatine was not added. After 30 days of storage, an effect of time and/or temperature was observed on creatinine recovery (P < 0.05). Urine samples can be stored at any temperature for up to 15 days after collection to estimate the creatinine concentration. Samples that need storage times longer than 15 days should be frozen (at -20 °C and -40 °C) to avoid creatinine concentration variation

Blood parameters of Angus and Nellore young bulls fed diets with or without forage

We evaluated blood parameters of Angus and Nellore bulls fed diets with and without forage. Forty animals with initial body weight (BW) of 380±16.2 kg were housed in individual stalls. Eight bulls of each breed were fed a whole shelled corn (WSC) diet [850 g kg−1 of WCS and 150 g kg−1 of a pellet based on soybean meal, dry mater (DM) basis] or a ground corn with silage (GC) diet (300 g kg−1 of silage and 700 g kg−1 of a concentrate based on corn and soybean meal, DM basis), ad libitum, and four animals of each breed were limited-fed the GC diet [feed restriction (FR), 55% of the DM intake of bulls fed ad libitum, adjusted for the metabolic BW]. Intake was measured daily, and a metabolism trial was conducted with total collection of feces and urine to estimate the ruminally degraded and undegraded protein (intake and nitrogen balance). Blood samples for determination of hormones and metabolites were collected. The data were analyzed using the GLM procedure of SAS adopting a significance level of 0.05. The diet affected only the serum concentrations of triglycerides, HDL, and VLDL, with limitedfed animals presenting smaller concentrations than ad libitum-fed bulls. No difference in blood parameters was observed between animals fed WSC or GC diets. Nellore bulls presented greater T4, cholesterol, HDL, LDL, and serum urea nitrogen concentrations than Angus. Feeding finishing beef cattle with no-roughage diets does not alter their blood parameters. Also, our results support that Zebu cattle might have lower serum removal of nutrients due to a lesser demand for fat and protein deposition than Bos taurus tauru

Exigências de energia e proteína de bovinos castrados mestiços Holandês x Zebu alimentados com diferentes níveis de cálcio e fósforo na dieta

The aim of this study was to determine the energy and protein requirements of crossbred Holstein x Zebu steers fed with or without the supplementation of dicalcium phosphate in the diet. Thirty-two steers with an average initial body weight of 377.5 ± 49.4 kg were used, of which four were initially slaughtered to estimate the empty body weight (EBW) of the animals. Twenty-four steers were fed ad libitum and were distributed in a completely randomized design with two levels of concentrate (30 and 60 %), and diets with or without dicalcium phosphate and four steers were fed at maintenance level, so that the body weight gain was equal to zero. After 84 days the animals were slaughtered. The animal tissues were sampled, and composted by two samples, denominated by “carcass” (bone, muscle and fat) and “non-carcass” (head, limbs, blood, hide, organs and viscera) for determination of the body composition. The net energy requirements (NEm) and metabolizable energy for maintenance (MEm) were obtained while relating heat production (HP) and metabolizable energy intake (MEI); meanwhile, the net energy requirements for gain (NEg) and the net protein requirements for gain (NPg) were obtained as a function of empty body weight (EBW), empty body gain (EBG) and retained energy (RE) in EBW. The daily net and metabolizable energy requirements for maintenance were 76.90 and 119.36 kcal/EBW0.75, respectively. The net energy requirements for gain can be obtained by the following equation: NEg = 0.0568±0.0025 × EBW0.75 × EBG1.095. The efficiencies of use of metabolizable energy for maintenance and gain are 64.4 and 29.68 %, respectively. The metabolizable protein requirements for maintenance are 4.14 g/BW0.75. The net protein requirements for gain can be obtained through the following equation: NPg = 236.36±30.06 × EBG - 19.84±6.14 × RE. We recommend the use of the equations obtained in this experiment to calculate the energy and protein requirements of crossbred Holstein x Zebu steers.Objetivou-se determinar as exigências nutricionais de energia e proteína para bovinos castrados mestiços Holandês x Zebu alimentados com ou sem suplementação inorgânica de cálcio e fósforo na dieta. Foram utilizados 32 animais mestiços Holandês × Zebu, machos, castrados, com peso corporal (BW) médio inicial de 377,5 ± 49,4 kg, dos quais quatro foram abatidos inicialmente para estimar o peso de corpo vazio (EBW) dos demais, 24 alimentados ad libitum distribuídos em delineamento inteiramente casualizado com dois níveis de concentrado (30 e 60%) e dietas contendo ou não fosfato bicálcico; e quatro alimentados ao nível de mantença, isto é, para que o ganho de peso corporal fosse igual a zero. Após 84 dias os animais foram abatidos. Para determinação da composição corporal dos animais, foram constituídas duas amostras por animal, denominadas “carcaça” (óssos, musculo e gordura) e “não carcaça” (cabeça, membros, sangue, couro, orgãos e visceras). As exigências de energia líquida (NEm) e metabolizável para mantença (MEm) foram obtidas relacionando a produção de calor (HP) e o consumo de energia metabolizável (MEI), enquanto as exigências de energia líquidas para ganho de peso (NEg) e as exigências líquidas de proteína para ganho (NPg) foram obtidas em função do EBW, do ganho de peso de corpo vazio (EBG), e da energia retida (RE) no EBW. As exigências diárias de energia líquida e metabolizável para mantença de bovinos mestiços Holandês × Zebu castrados foram de 76,90 e 119,36 kcal/EBW0,75, respectivamente. As exigências de energia líquida para ganho podem ser obtidas pela equação: NEg = 0,0568±0,0025 × EBW0,75 × EBG1,095. As eficiências de uso da energia metabolizável para mantença e para ganho foram de 64,4 e 29,68%, respectivamente. As exigências de proteína metabolizável para mantença foram de 4,14 g/BW0,75. As exigências líquidas de proteína para ganho de peso podem ser obtidas através da equação NPg = 236,36±30,06 × EBG - 19,84±6,14 × RE. Recomenda-se o uso das equações obtidas nesse experimento para cálculo das exigências nutricionais de energia e proteína para novilhos cruzados Holandês × Zebu castrados

Energy and protein requirements of crossbred Holstein x Zebu steers fed different levels of calcium and phosphorus in the diet

The aim of this study was to determine the energy and protein requirements of crossbred Holstein x Zebu steers fed with or without the supplementation of dicalcium phosphate in the diet. Thirty-two steers with an average initial body weight of 377.5 ± 49.4 kg were used, of which four were initially slaughtered to estimate the empty body weight (EBW) of the animals. Twenty-four steers were fed ad libitum and were distributed in a completely randomized design with two levels of concentrate (30 and 60 %), and diets with or without dicalcium phosphate and four steers were fed at maintenance level, so that the body weight gain was equal to zero. After 84 days the animals were slaughtered. The animal tissues were sampled, and composted by two samples, denominated by “carcass” (bone, muscle and fat) and “non-carcass” (head, limbs, blood, hide, organs and viscera) for determination of the body composition. The net energy requirements (NEm) and metabolizable energy for maintenance (MEm) were obtained while relating heat production (HP) and metabolizable energy intake (MEI); meanwhile, the net energy requirements for gain (NEg) and the net protein requirements for gain (NPg) were obtained as a function of empty body weight (EBW), empty body gain (EBG) and retained energy (RE) in EBW. The daily net and metabolizable energy requirements for maintenance were 76.90 and 119.36 kcal/EBW 0.75 , respectively. The net energy requirements for gain can be obtained by the following equation: NEg = 0.0568 ±0.0025 × EBW 0.75 × EBG 1.095 . The efficiencies of use of metabolizable energy for maintenance and gain are 64.4 and 29.68 %, respectively. The metabolizable protein requirements for maintenance are 4.14 g/BW 0.75 . The net protein requirements for gain can be obtained through the following equation: NPg = 236.36 ±30.06 × EBG - 19.84 ±6.14 × RE. We recommend the use of the equations obtained in this experiment to calculate the energy and protein requirements of crossbred Holstein x Zebu steers.Objetivou-se determinar as exigências nutricionais de energia e proteína para bovinos castrados mestiços Holandês x Zebu alimentados com ou sem suplementação inorgânica de cálcio e fósforo na dieta. Foram utilizados 32 animais mestiços Holandês × Zebu, machos, castrados, com peso corporal (BW) médio inicial de 377,5 ± 49,4 kg, dos quais quatro foram abatidos inicialmente para estimar o peso de corpo vazio (EBW) dos demais, 24 alimentados ad libitum distribuídos em delineamento inteiramente casualizado com dois níveis de concentrado (30 e 60%) e dietas contendo ou não fosfato bicálcico; e quatro alimentados ao nível de mantença, isto é, para que o ganho de peso corporal fosse igual a zero. Após 84 dias os animais foram abatidos. Para determinação da composição corporal dos animais, foram constituídas duas amostras por animal, denominadas “carcaça” (óssos, musculo e gordura) e “não carcaça” (cabeça, membros, sangue, couro, orgãos e visceras). As exigências de energia líquida (NEm) e metabolizável para mantença (MEm) foram obtidas relacionando a produção de calor (HP) e o consumo de energia metabolizável (MEI), enquanto as exigências de energia líquidas para ganho de peso (NEg) e as exigências líquidas de proteína para ganho (NPg) foram obtidas em função do EBW, do ganho de peso de corpo vazio (EBG), e da energia retida (RE) no EBW. As exigências diárias de energia líquida e metabolizável para mantença de bovinos mestiços Holandês × Zebu castrados foram de 76,90 e 119,36 kcal/EBW 0,75 , respectivamente. As exigências de energia líquida para ganho podem ser obtidas pela equação: NEg = 0,0568 ±0,0025 × EBW 0,75 × EBG 1,095 . As eficiências de uso da energia metabolizável para mantença e para ganho foram de 64,4 e 29,68%, respectivamente. As exigências de proteína metabolizável para mantença foram de 4,14 g/BW 0,75 . As exigências líquidas de proteína para ganho de peso podem ser obtidas através da equação NPg = 236,36 ±30,06 × EBG - 19,84 ±6,14 × RE. Recomenda-se o uso das equações obtidas nesse experimento para cálculo das exigências nutricionais de energia e proteína para novilhos cruzados Holandês × Zebu castrados

Effects of Increasing Levels of Palm Kernel Oil in the Feed of Finishing Lambs

The aim of this study was to evaluate the effects of the inclusion of palm kernel oil (PKO) in a lamb diet on nutrient intake, digestibility, ingestive behavior, nitrogen balance, blood metabolites, rumen fermentation parameters, and animal performance. Three experimental trials were conducted. The treatments consisted of varying levels of PKO included in the diet, with PKOzero = no PKO inclusion, PKO1.3 = 1.3% addition, PKO2.6 = 2.6% addition, PKO3.9 = 3.9% addition, and PKO5.2 = 5.2% addition, based on the total dry matter (DM) of the diet. With the inclusion of PKO in the diet, linear decreases in DM (p p p p p p = 0.021) intake were observed, as was an increase in ether extract (EE) intake (p p = 0.035), EE (p p p p p p p p = 0.048) with increasing PKO levels. PKO addition had no effect on total weight gain and average daily gain; however, feed conversion improved (p = 0.001) with increasing PKO levels. The intake, digestibility, ingestive behavior, and growth performance of lambs with PKO1.3 added to their diet were similar to animals that did not receive PKO, meaning that PKO could be an alternative energy source for growing lambs because it does not harm animal performance and can lower the cost of feed

Digestibility, ingestive behavior, and nitrogen balance in goat kids fed a diet containing dehydrated passion fruit residue

The objective was to determine the optimal dehydrated passion fruit pulp replacing ground corn in diets for goat kids. We used 24 crossbred castrated goat kids with initial body weight of 26.6±0.3 kg. The experimental period was 23 days, with 15 days of adjustment and acclimatization (mostly to the installation and diet). Kids were distributed in a randomized experimental design with four treatments of 0, 80, 160, or 240 g/kg of dehydrated passion fruit residue as a supplementary inclusion in the dry matter (DM) content of the diet. The statistical model considered the fixed effect of the included amount of residue from dehydrated passion fruit. Analysis of variance was conducted using the PROC GLM of SAS. Intakes of DM and total digestible nutrients (TDN) were not affected by residue inclusion. However, neutral detergent fiber (NDF) intake increased linearly. The inclusion linearly decreased intake of ether extract (EE) and non-fibrous carbohydrates (NFC). Crude protein (CP) intake was quadratically affected, with a greater value under treatment of 160 g/kg passion fruit. Dry matter and NFC digestibility decreased linearly with the amount of passion fruit included in diet. Fecal N and total N excretion values (in g/d and %N intake) increased linearly. Nitrogen balance and N retained values showed a quadratic increase, with greater values under the 160 g/kg inclusion. Time spent ruminating, DM and NDF eating efficiency, and g DM/bolus chewed were affected quadratically by inclusion of passion fruit residue. The replacement of ground corn with dehydrated passion fruit residue at a level of 160 g/kg is recommended for diets of goat kids to improve their NDF and CP intake and their N balance without affecting DM and TDN intake

Dietary Effect of Palm Kernel Oil Inclusion in Feeding Finishing Lambs on Meat Quality

This study evaluated the effects of palm kernel oil (PKO) in the diet of lambs on carcass characteristics, quality, and fatty acid profile of the meat. Forty uncastrated male Santa Inês lambs were used and divided among the treatments: PKOzero without inclusion; PKO1.3—added 1.3%; PKO2.6—added 2.6%; PKO3.9—added 3.9%; PKO5.2—added 5.2%. The carcass characteristics, the variables related to meat color, and the chemical composition of the Longissimus lumborum of lambs were not affected by the PKO inclusion. The weight of the carcasses at slaughter, hot and cold, half carcass, loin-eye area, and commercial cuts decreased linearly when PKO was added to the lamb diet (p < 0.01). CCY decreased linearly to the inclusion level of 2.66% PKO (RMSE 2.204). Total conjugated linoleic acid CLA and C18:3 n-3 GA concentrations remained stable until the inclusion levels of 3.44% PKO (RMSE 0.0956) and 2.17% (RMSE 0.0637), decreasing its concentrations as the increased level of PKO. The presence of PKO in the lambs’ diet up to the level of 5.2% did not change the meat quality characteristics; thus, from the point of view of lamb meat production and fatty acid profile, the inclusion of PKO is not beneficial