Does virginiamycin supplementation affect the metabolism and performance of Nellore bulls grazing under low and high gain rates?

This study aimed to evaluate the effect of virginiamycin on the metabolism and performance of growing Nellore bulls under low and high gain rates on pasture. In experiment 1, 80 Nellore bulls (age = 12 ± 2 months, body weight = 258 ± 15 kg) were assigned to 16 paddocks in a 2 × 2 randomized block factorial arrangement. In experiment 2, 12 cannulated Nellore bulls were assigned to three 4 × 4 balanced Latin squares. The factors were: (1) mineral salt without or with virginiamycin, and (2) low or high gain rate. No interaction was noted between factors (p > .10). Animals fed virginiamycin had greater average daily gain (14%, p < .01), body weight (11 kg, p = .05), plasma nonesterified fatty acid (20%, p < .01), serum calcium concentration (2.62%, p = .04), and total protozoa (p = .03) and had the same bacterial proportion (p > .27). Animals with a low gain rate had greater serum urea concentration (19.6%, p < .01) and ruminal ammonia nitrogen (62%, p < .01). Thus, virginiamycin increases the performance and changes the metabolism of growing Nellore bulls under low and high gain rates on pasture.

Comparison of laboratory methods to assess fiber contents in feedstuffs / Comparación de métodos de laboratorio para determinar el contenido de fibra en alimentos para animales / Comparação de metodologias laboratoriais para determinação de fibras em alimentos

Summary Background: the conventional method of fiber analysis using neutral detergent fiber (NDF) and acid detergent fiber (ADF) was proposed by Peter Van Soest. The main advantage of this method is the precision of results; however, reagents are costly and laboratory work requires long runtime and labor. Objective: to compare analytical data from different methodologies used to assess NDF and ADF contents. Methods: means obtained with the conventional method were compared through Dunnett's test (α=5%) with values from alternative methods using autoclave as the digester system. A completely randomized design in a 4 x 2 factorial arrangement was used. Results: NDF content through alternative methods was assessed for Tifton 85 hay, babassu meal and sugarcane, whereas ADF was only determined for babassu meal. NDF and ADF did not differ (p(0.05) between non-sequential or sequential analysis for all the feedstuffs and methods studied, except for ADF in corn silage. Conclusion: alternative methodologies allow reducing operating costs and time but lack uniformity and accuracy for analyzing ADF in corn silage.

Resumen Antecedentes: la determinación de los valores de fibra detergente neutra (FDN) y fibra detergente ácida (FDA) es de gran importancia en la nutrición animal, siendo el método tradicional de análisis el propuesto por Van Soest. Este método presenta como ventaja principal la precisión de los resultados, sin embargo la rutina de laboratorio en su ejecución implica mucho tiempo debido a sus etapas manuales, además de ser un método de alto costo que genera considerables proporciones de residuos químicos. Objetivo: evaluar diferentes metodologías propuestas para la análisis de las FDN y FDA mediante la medición de los datos analíticos. Métodos: las medias obtenidas por el método tradicional fueron comparadas con las medias de métodos alternativos que usan una autoclave como sistema digestor por el test de Dunnette (α=5%). Un diseño completamente aleatorio, en un diseño factorial 4x2 fue adoptado. Resultados: los métodos alternativos fueron recomendadas para las determinaciones de FDN por el heno de Tifton 85, salvado de harina de babasú y caña de azúcar, mientras que las determinaciones de los valores de FDA apenas para el salvado de harina de babasú. Los resultados de los análisis de FDN y FDA no fueron significativamente diferentes (p(0.05) entre los análisis no secuencial y secuencial, en todos los alimentos y métodos estudiados, a excepción de la determinación de FDA en el ensilaje de maíz. Conclusión: las metodologías alternativas permitieron ganancias significativas con la reducción de costos operacionales y del tiempo de análisis, pero sin uniformidad en la precisión de los análisis involucrados.

Resumo Antecedentes: as determinações dos teores de fibra em detergente neutro (FDN) e em fibra em detergente ácido (FDA) são de extrema importância na nutrição animal, tendo como método convencional de análise o proposto por Van Soest. Esse método apresenta como principal vantagem a precisão dos resultados, no entanto, a rotina laboratorial da sua execução demanda muito tempo por possuir etapas manuais, além do que é um método de custo elevado e que gera resíduos químicos em proporções consideráveis. Objetivo: avaliar diferentes metodologias propostas para análise da FDN e FDA, através da verificação dos dados analíticos. Métodos: as médias obtidas pelo método convencional foram comparadas com as médias de métodos alternativos que utilizam a autoclave como sistema digestor, pelo teste de Dunnette (α=5%). O delineamento adotado foi o inteiramente casualizado, em um esquema fatorial 4x2. Resultados: os métodos alternativos foram recomendados para determinação de FDN no feno de Tifton 85, farelo de babaçu e cana-de-açúcar, enquanto para as determinações dos teores de FDA, apenas no farelo de babaçu. A precisão observada nas análises dos teores de FDN e FDA não diferiram significativamente (p(0.05) quanto a análise não sequencial e sequencial, em todos os alimentos e métodos estudados, com exceção da determinação de FDA na silagem de milho. Conclusão: as metodologias alternativas permitiram ganhos significativos com a redução dos custos operacionais e do tempo da análise, mas sem uniformidade na precisão das análises desenvolvidas.

Prediction of crude protein digestibility of animal by-product meals for dogs by the protein solubility in pepsin method.

Animal by-product meals have large variability in crude protein (CP) content and digestibility. In vivo digestibility procedures are precise but laborious, and in vitro methods could be an alternative to evaluate and classify these ingredients. The present study reports prediction equations to estimate the CP digestibility of meat and bone meal (MBM) and poultry by-product meal (PM) using the protein solubility in pepsin method (PSP). Total tract CP digestibility of eight MBM and eight PM samples was determined in dogs by the substitution method. A basal diet was formulated for dog maintenance, and sixteen diets were produced by mixing 70 % of the basal diet and 30 % of each tested meal. Six dogs per diet were used to determine ingredient digestibility. In addition, PSP of the MBM and PM samples was determined using three pepsin concentrations: 0·02, 0·002 and 0·0002 %. The CP content of MBM and PM ranged from 39 to 46 % and 57 to 69 %, respectively, and their mean CP digestibility by dogs was 76 (2·4) and 85 (2·6) %, respectively. The pepsin concentration with higher Pearson correlation coefficients with the in vivo results were 0·0002 % for MBM (r 0·380; P = 0·008) and 0·02 % for PM (r 0·482; P = 0·005). The relationship between the in vivo and in vitro results was better explained by the following equations: CP digestibility of MBM = 61·7 + 0·2644 × PSP at 0·0002 % (P = 0·008; R (2) 0·126); and CP digestibility of PM = 54·1 + 0·3833 × PSP at 0·02 % (P = 0·005; R (2) 0·216). Although significant, the coefficients of determination were low, indicating that the models were weak and need to be used with caution.

Peritoneal fluid changes in horses subjected to small colon distension / Alterações no líquido peritoneal de equinos submetidos a distensão do cólon menor

Intestinal devitalization in cases of small colon obstruction may be difficult to detect based only in clinical signs. The purpose was to serially evaluate blood and peritoneal fluid of horses subjected to small colon distension. Seventeen adult horses were allotted in three groups. In the small colon-distended group (DG, n=7) a surgically-implanted latex balloon was inflated to promote intraluminal small colon distension. In the shamoperated group (SG, n=5), the balloon was implanted but not inflated, and no surgery was done in the control group (CG, n=5). Blood and peritoneal fluid were sampled before and after (6 samples with a 30-minute interval) intestinal obstruction for cytological and biochemical analyses. No significant changes in clinical signs occurred within groups or across time during the experimental period. There were no statistical differences among SG and SG groups in hematologic and blood chemistry variables. Although total protein concentration and lactate dehydrogenase (LDH) activity in peritoneal fluid remained most of the time within reference values during the experimental period in all groups, increases from baseline values were detected in SG and DG groups. Such increases occurred earlier, progressively and with greater magnitude in the DG when compared with the SG (P<0.05). Increases from baselines values were also observed in total nucleated cells and neutrophils counts in the DG (P<0.05). In conclusion, distension of the equine small colon induced progressive subtle increases in total protein and LDH concentrations in the peritoneal fluid during the first hours. Serial evaluation of these variables in peritoneal fluid may be useful for early detection of intestinal devitalization in clinical cases of equine small colon obstruction.

A desvitalização do cólon menor em equinos pode ser difícil de ser detectada baseando-se apenas em sinais clínicos. O objetivo foi realizar uma avaliação seriada do líquido peritoneal de equinos submetidos à distensão do cólon menor. Dezessete cavalos adultos foram divididos aleatoriamente em três grupos. No grupo distendido (DG, n=7) um balão implantado cirurgicamente foi inflado para promover distensão do cólon menor. No grupo instrumentado (SG, n=5) o balão foi implantado, mas sem promover distensão e no grupo controle (CG, n=5) não houve anestesia ou cirurgia. Sangue e fluido peritoneal foram colhidos antes e durante 180 minutos após a cirurgia para análises citológicas e bioquímicas. Nenhuma interação significativa ocorreu entre grupos e tempos nas variáveis clínicas e hematológicas. Apesar dos valores de proteínas totais e da atividade da lactato desidrogenase (LDH) permanecerem dentro da normalidade durante quase todo o experimento, aumentos em relação aos valores basais ocorreram nos grupos SG e DG. Contudo, tais aumentos foram precoces, progressivos e em maior magnitude em DG quando comparados ao SG, mostrando que a distensão promoveu alterações significativas nessas variáveis (P<0.05). Aumentos em relação aos valores basais também ocorreram nas contagens de células totais nucleadas e neutrófilos (P<0.05). Em conclusão, a distensão experimental do cólon menor promove, nas primeiras horas, alterações subliminares progressivas nas concentrações de proteínas totais e na atividade de LDH no líquido peritoneal. Os resultados indicam que a avaliação seriada do liquido peritoneal pode ser útil para detectar desvitalização intestinal em casos clínicos de obstrução do cólon menor equino.

Protein intake during weight loss influences the energy required for weight loss and maintenance in cats.

The effects of 2 diets with different protein contents on weight loss and subsequent maintenance was assessed in obese cats. The control group [Co; n = 8; body condition score (BCS) = 8.6 +/- 0.2] received a diet containing 21.4 g crude protein (CP)/MJ of metabolizable energy and the high-protein group (HP; n = 7; BCS = 8.6 +/- 0.2) received a diet containing 28.4 g CP/MJ until the cats achieved a 20% controlled weight loss (0.92 +/- 0.2%/wk). After the weight loss, the cats were all fed a diet containing 28.0 g CP/MJ at an amount sufficient to maintain a constant body weight (MAIN) for 120 d. During weight loss, there was a reduction of lean mass in Co (P < 0.01) but not in HP cats and a reduction in leptinemia in both groups (P < 0.01). Energy intake per kilogram of metabolic weight (kg(-0.40)) to maintain the same rate of weight loss was lower (P < 0.04) in the Co (344 +/- 15.9 kJ x kg(-0.40) x d(-1)) than in the HP group (377 +/- 12.4 kJ. x kg(-0.40) x d(-1)). During the first 40 d of MAIN, the energy requirement for weight maintenance was 398.7 +/- 9.7 kJ.kg(-0.40) x d(-1) for both groups, corresponding to 73% of the NRC recommendation. The required energy gradually increased in both groups (P < 0.05) but at a faster rate in HP; therefore, the energy consumption during the last 40 d of the MAIN was higher (P < 0.001) for the HP cats (533.8 +/- 7.4 kJ x kg(-0.40) x d(-1)) than for the control cats (462.3 +/- 9.6 kJ x kg(-0.40) x d(-1)). These findings suggest that HP diets allow a higher energy intake to weight loss in cats, reducing the intensity of energy restriction. Protein intake also seemed to have long-term effects so that weight maintenance required more energy after weight loss.