Respirometry and Ruminant Nutrition

The gaseous exchange between an organism and the environment is measured by respirometry or indirect calorimetry. Once the oxygen consumption (O2) and the production of carbon dioxide (CO2) and methane (CH4) are known, the energy losses by gas and heat can be calculated. Energy metabolism and methane production have been studied in the Calorimetry and Metabolism Laboratory of the Federal University of Minas Gerais, located in Belo Horizonte, Minas Gerais, Brazil. Animals used are mainly Zebu cattle and their crossbreeds that represent most beef and dairy cattle breed grazed on tropical pastures. System calibration and routine work are addressed in this text. The results obtained on respirometric chambers are expressed in net energy (NE), which can be net energy for maintenance (NEm), lactation (NEL), weight gain (NEg), and pregnancy (NEp). NE is, in fact, what is used by the animal for maintenance and each productive function. The values of k (conversion efficiency of ME into NE) for maintenance (km), milk (kL), weight gain or growth (kg), and pregnancy (kp) are determined. Thanks to the peculiarity of the respirometric technique, the same animal can be evaluated several times, in different physiological states and planes of nutrition

Uso da LIPE® como indicador externo na determinação da digestibilidade da proteína e matéria seca de alimentos em frangos de corte Use of LIPE® as an external indicator in the determination of protein and dry matter digestibility of broiler chicken food

Realizou-se um ensaio metabólico para avaliar a lignina purificada de eucalipto (LIPE®), como indicador na determinação da digestibilidade da proteína bruta e matéria seca de alimentos para frangos de corte. Os tratamentos corresponderam a uma dieta basal e outras oito dietas contendo os alimentos-teste. Os alimentos foram: milho, milho expandido, farelo de soja, farelo de soja expandido, glúten de milho 22%, glúten de milho 60%, farinha de carne e ossos e farinha de penas e vísceras. Os alimentos protéicos e os com menor teor de proteína substituíram 25 e 40% da dieta basal, respectivamente. Foram utilizados 270 pintos de corte, linhagem Ross, de ambos os sexos, dos 21 aos 31 dias de idade. Utilizou-se um delineamento experimental inteiramente ao acaso em esquema fatorial 9×3 (rações × métodos), com três repetições. Os coeficientes de digestibilidade (CD) da proteína e da matéria seca e os valores da proteína bruta digestível e da matéria seca digestível de sete das nove dietas, calculados pelos métodos da coleta total de excretas e dos indicadores óxido crômico e LIPE®, foram semelhantes. Com os alimentos-teste, farelo de soja expandido e farinha de penas e vísceras, o uso de óxido crômico resultou em CD e valores de proteína e matéria seca digestível mais altos, quando comparado com o uso da LIPE® e da coleta total de excretas que foram semelhantes entre si. Pode-se considerar que a proteína bruta digestível e matéria seca digestível dos alimentos, calculada pelos três métodos, foram equivalentes. A LIPE® pode ser validada como indicador de digestibilidade da proteína e matéria seca de alimentos para frangos de corte.A metabolism experiment was carried out to evaluate the use of LIPE® as an external indicator of dry matter and protein digestibility in broilers. The treatments corresponded to a basal diet and eight other different diets. The foods used were: corn grain, expanded corn, soybean meal, expanded soybean meal, gluten meal 22% crude protein; gluten meal 60% crude protein, meat and bone meal and feather meal. The basal diet was replaced with 40% or 25% of the food containing more energy or protein, respectively. Two hundred and seventy broiler chickens were used from 21 to 31 days old. A completely randomized design in a 9x3 factorial arrangement (nine forms of rations x three methods) with three replicates was used. The digestible dry matter and protein and metabolizable energy of the food was calculated by the total fecal collection method and by the indicator methods of chromic oxide and LIPE®; the three methods were further compared. Chromic oxide use resulted in higher values of coefficient of digestibility for expanded soybean meal and feathers and viscera meal when compared to the use of LIPE® and total feces collection which were similar. The results validated the LIPE® as an external protein and dry matter digestibility index of the feed of broiler chicks evaluated

Ruminal and morphometric parameters of rumen and intestine in lambs fed guava (Psidium guajava L.) agroindustrial waste

The objective of this study was to evaluate the effect of guava agroindustrial waste (GAW) on ruminal parameters (pH, N-NH3 , and microbial protein), volatile fatty acid (VFA), and morphometry of the rumen and intestine of sheep. A total of forty Santa Inês sheep (120 days old and 21.3±2.62 kg) were used. The animals were fed diets with 0, 7.5, 15, 22.5, and 30% inclusion of GAW. The pH, ammonia nitrogen, microbial protein, and VFA were evaluated in the ruminal fluid, alongside the morphometric characteristics of the rumen and intestine. The inclusion of GAW linearly increased fasting and postprandial pH, N-NH3 only showed a quadratic effect for fasting animal, whereas MP presented a quadratic effect for pre- and post-prandial animals. There was a quadratic effect for papilla width, with a maximum value of 393.33 μm at the level of 34.43% GAW in the diet. The papilla absorption area showed a linear effect, in which increasing levels of GAW in the diet had a smaller area of papillae absorption. The inclusion of GAW in the diet of Santa Inês sheep favored pH neutrality, reduced N-NH3 and ruminal MP concentrations, decreased the thickness of the rumen muscular layer, and increased the intestinal mucosa, favoring greater absorption of nutrient

Intake and digestibility of concentrate and legume hay diets fed to foals

This study was carried out to evaluate intake, nutrient digestibility and body weight gain of foals on diets of concentrate and legume hay. Treatments were: lucerne hay (Medicago sativa), Campo Grande stylo hay (20% Stylosanthes macrocephala and 80% Stylosanthes capitata) and Mineirão stylo hay (Stylosanthes guianensis cv. Mineirão). Fifteen weaned foals at 160 Kg body weight (BW) were used. The experiment was entirely randomized with three treatments and five replicates. Dry matter intake was estimated at 30 g of dry matter (DM)/kg BW and was comprised of 40% concentrate meal and 60% hay. Fecal production and nutrient digestibility were calculated by the LIPE® marker methodology. There was no difference between Lucerne hay and Campo Grande stylo hay intake, but intake of Mineirão stylo hay was lower than that of Lucerne hay. Body weight gain and nutrient digestibility coefficients were similar for foals fed different diets. Intake was similar for Campo Grande and Lucerne hay, and led to similar body weight gain in diets with concentrate. Mineirão stylo hay, at 137 days of growth, was not palatable for the foals

Validação do Lipe® como método para determinar a digestibilidade dos nutrientes em eqüinos Validation of Lipe® as method to evaluate the apparent digestibility of nutrients in equines

Avaliou-se a eficiência da lignina purificada e enriquecida (Lipe®) como indicador externo para estimar a digestibilidade dos nutrientes de dietas em eqüinos em comparação aos métodos de coleta total de fezes e do indicador óxido crômico. Foram utilizadas seis potras Mangalarga Marchador, com média de 2 anos de idade e 345 kg de peso vivo, alimentadas com feno de alfafa e concentrado comercial na proporção de 50:50, para ingestão de matéria seca de 3,1%PV, e sal mineral. O experimento teve duração de 29 dias, de modo que os 24 dias iniciais foram destinados à adaptação dos animais à dieta e às instalações e os cinco finais para coleta total das fezes. Utilizou-se delineamento em blocos casualizados, no qual cada animal constituiu um bloco e cada método de determinação da digestibilidade, um tratamento. Os cálculos de produção fecal e digestibilidade de cada nutriente foram feitos utilizando-se os indicadores e a taxa de recuperação fecal de cada nutriente. Os coeficientes de digestibilidade dos nutrientes obtidos utilizando-se o óxido crômico foram superiores aos da coleta total e Lipe®. Os resultados obtidos com Lipe® foram similares aos determinados por coleta total. O método do óxido crômico é inadequado, enquanto o Lipe® é eficiente para estimar a digestibilidade de nutrientes da dieta em eqüinos.<br>The objective of this work was to test the efficiency of enriched and purified lignin, Lipe®, as external indicator in order to estimate the apparent digestibility of the nutrients in equine diets, compared with the total feces collection and the chromic oxide methods. Six female Mangalarga Marchador with average of two years of age and average weight of 331 kg were used. The diet was alfalfa hay, commercial grain and mineral salt. The experimental period was of 29 days, the first 24 used for the adaptation of animals to the diet and facilities and the last five days for feed estimation and total feces collection. A random blocks design was used in which each animal constituted one block and each digestibility determination method, one treatment. The digestibility of nutrients using chromic oxide were smaller than those from the total collection and Lipe®, and those estimated by the Lipe® were similar to those from the total collection. Chromic oxide revealed to be inadequate and Lipe® was considered efficient to estimate the apparent digestibility in equine