ABSTRACT Aimed with this study was evaluate the increasing levels of crambe crushed, on in vitro digestibility of dry matter (IVDDM), organic matter (IVDOM) and crude protein (IVDCP), parameters of fermentation and kinetics of the cumulative gas production. The crushed crambe were included in the diets at 0; 50; 100; 150 g/kg of DM. There was a quadratic effect of the proportions of crambe crushed in the concentrated supplements on IVDDM and IVDOM (maximum point at 0.25 and 0.91 g Kg-1 DM, respectively). Total gas production (A + D) was influenced by the presence of crambe crushed with quadratic effect on minimal point on 0.02 g Kg-1 DM. There was a quadratic effect for pH in the collection times in all diets, the lowest pH values were observed between 4.8 to 8.7 hours. There was a quadratic effect for ammoniacal nitrogen in the collection times in all diets with peaks of NH3-N production occurred between 4.8 and 6.3 hours after the beginning of the incubation. Concluded that the inclusion of crambe crushed up to 150 g kg-1 DM in diets for ruminants does not impair the ruminal degradation kinetics. IVDDM, , (IVDDM) (IVDOM IVDCP, IVDCP (IVDCP) 0 50 100 15 gkg kg maximum 025 25 0.2 091 91 0.9 Kg1 Kg 1 Kg- respectively. respectively . respectively) A D 002 02 0.0 48 4 8 4. 87 7 8. NH3N NHN NH3 N NH 63 6 3 6. incubation kg1 kg- (IVDDM (IVDCP 5 10 2 0. 09 9 00

RESUMO O objetivo deste estudo foi avaliar a inclusão de níveis crescentes de torta de crambe, sobre a digestibilidade in vitro da matéria seca (DIVMS), matéria orgânica (DIVMO) e proteína bruta, cinética da produção cumulativa de gás e parâmetros de fermentação. Foram avaliadas as inclusões de 0; 50; 100; 150 g / kg de MS em dietas. Houve efeito quadrático das proporções de torta de crambe nos suplementos concentrados para DIVMS e DIVMO (ponto máximo em 0,25 e 0,91 g Kg-1 DM, respectivamente). A produção total de gás (A + D) foi influenciada por a presença de torta de crambe com efeito quadrático tendo como ponto mínimo em 0,02 g kg-1 DM. Houve um efeito quadrático do pH e NH3-N nos tempos de coleta em todas as dietas, os menores valores de pH foram observados entre 4,8 a 8,7 e os picos de produção de NH3-N entre 4,8 e 6,3 horas após o início da incubação. Conclui-se que a substituição do farelo de soja por crambe triturado até 150 g kg-1 em suplementos concentrados para ruminantes não prejudica a cinética de degradação ruminal. DIVMS, , (DIVMS) (DIVMO bruta fermentação 0 50 100 15 dietas 025 25 0,2 091 91 0,9 Kg1 Kg 1 Kg- DM respectivamente. respectivamente . respectivamente) D 002 02 0,0 kg1 kg- NH3N NHN NH3 N NH 48 4 8 4, 87 7 8, 63 6 3 6, incubação Concluise Conclui se ruminal (DIVMS 5 10 2 0, 09 9 00

Incorporating olive pomace (OP) into ruminant feed can alleviate the environmental impact of OP disposal, minimize food-feed competition, and bolster food security. However, high fibre and low crude protein (CP) reduce its nutritional value for ruminants. The study assessed the effect of oyster mushrooms (OYM) on the nutritive value of OP. To this end, chemical composition and in vitro ruminal fermentation parameters of spent OP substrate were evaluated. The OYM was spawned on 200 g OP at the rate of 0 (OP0), 10 (OP10), 20 (OP20), 30 (OP30), 40 (OP40), and 50% w/w (OP50) and cultivated for 35 d with 10 replicate pots per spawning rate. Dry matter, organic matter, CP, and ash increased linearly, whereas neutral detergent fibre and crude fat declined linearly. In vitro cumulative gas production at 12, 24, 36, 48, 72, and 96 h showed a positive quadratic response. Spawning rates linearly enhanced the immediately fermentable fraction (a) and rate of gas production from the slowly fermentable fraction (c), while the partitioning factor increased linearly. Positive quadratic responses were noted for the slowly fermentable fraction, potential gas production, effective gas production, and in vitro organic matter degradation at 96 h of ruminal incubation. In conclusion, OYM enhanced the nutritive value of OP by reducing fibre content, a, and c fractions while improving CP content and fermentation efficiency. This approach facilitates the bioconversion of OP into sustainable ruminant feed, leading to lower feed costs, addressing waste disposal issues, and creating supplementary income for the olive oil industry.

The aim of this study was to determine whether the inclusion of a marine algae found in South African waters, Ulva lactuca, can reduce total gas and methane production in vitro when it replaces lucerne hay in a mixed sheep feed at incremental levels. Four treatments were prepared and incubated using bovine rumen fluid as inoculum: (1) 0 g U. lactuca kg¹ feed dry matter (DM) (0U), (2) 25 g U. lactuca kg¹ feed DM (25U), (3) 50 g U. lactuca kg¹ feed DM (50U), and (4) 100 g U. lactuca kg¹ feed DM (100 U). Total gas and CO2 production was determined with the aid of an automated system and methane production was estimated by difference. Cumulative gas production data were fitted to a non-linear model (Y = b(1-exp c(t-L))) to estimate values for total gas production (b, mL), rate of gas production (c, mL/h), and a discrete lag time (L, hours). The extent of total gas production was lower for 100U than for 25U, but neither differed from 0U or 50 U. The lag time observed was lower for 50U than 0U, but neither differed from 25U or 100U. No differences were found for the rate of gas production. No differences for any gas production values were observed between treatments. The ratio between methane and total gas production was highest for 100U, which differed from 25U, but not from 0U or 50U. The higher methane ratio observed in the 100U treatment may be attributed to the lower total gas production in this treatment due to the lower fermentability of U. lactuca compared to lucerne.

Resumen Las hojas y las vainas de las leguminosas son una alternativa de alimentación de rumiantes en el trópico. El objetivo del presente estudio fue determinar las características químicas y fermentativas in vitro de vaina y hoja de Moringa oleifera, con inclusiones de 0%, 10%, 20% y 30% en una dieta integral para becerros de 200 kg de peso vivo. A las hojas, las vainas y las dietas se les determinó materia seca (ms), proteína cruda (pc), fibra detergente (fdn), producción acumulada de gas y metano, degradación de ms (dmd) y fdn (dfdn). El análisis de las variables fue mediante un diseño completamente al azar (10 repeticiones) y la hoja cuantificó 229,4, 465,8 y 204,0 g/kg ms de ms, fdn y pc, respectivamente. Así como, 662,3 y 688,9 g/kg de ms de dms y dfdn (P < 0,05). La dieta con 10% de hoja de M. oleifera presentó 824,9 y 725,5 g/kg de ms de dmd y dfdn, así como 167 y 58 ml/g ms de gas y metano. En conclusión, la hoja de M. oleifera muestra mejores características químicas y fermentativas in vitro y se puede incluir hasta 30% de hoja de M. oleifera en dietas integrales para becerros de 200 kg de peso vivo.

Abstract Legume leaves and pods are an alternative feed for ruminants in the tropics. The goal of this study was to determine the chemical quality and in vitro fermentative characteristics of Moringa oleifera pods and leaves, with inclusions of 0 %, 10 %, 20 % and 30 % in a complete diet for calves of 200 kg live weight. Dry matter (dm), crude protein (cp), neutral detergent fiber (ndf), cumulative gas and methane production, dm degradation (dmd) and ndf (ndfd) were determined from the leaves, pods and diets. The variables were analyzed using a completely randomized design (10 replicates). The leaf quantified 229.4, 465.8 and 204.0 g/kg dm, ndfand cp. As well as 662.3 and 688.9 g/kg dm of dmd and ndfd (P < 0.05). The diet with 10% M. oleifera leaf presented 824.9 and 725.5 g/kg dm of dmd and ndfd; as well as 167 and 58 ml/g dmof gas and methane. In conclusion, M. oleifera leaf shows better chemical and fermentative characteristics in vitro and up to 30% M. oleifera leaf can be included in whole-calf diets for calves of 200 kg live weight.

Usefulness of red grape pomace (GP) by-product in ruminant rations is restricted by its high fibre content. Pre-treatment with exogenous carbohydrases may partly resolve this problem. Therefore, the effects of various levels of an exogenous fibrolytic enzyme mixture (Viscozyme® L) on chemical nutrient content and in vitro ruminal fermentation of GP were studied. This product, with an enzyme activity of >100 fungal beta-glucanase per gram (FBG/g) and a density of 1.2 g/mL, was applied to GP at 0 (ENZ0), 20 (ENZ20), 30 (ENZ30), 35 (ENZ35), and 45 g/kg DM (ENZ45). Neutral detergent fibre (NDF), acid detergent fibre (ADF) and insoluble condensed tannins (ICT) declined linearly as enzyme levels increased. Significant negative linear trends were observed for the rate of gas production at 36 and 48 hours, whereas quadratic trends were observed at 12- and 24-hours incubation in response to enzyme levels. Cumulative gas production at 12 hours and 24 hours and in vitro organic matter degradability at 96 hours post incubation increased linearly as treatment levels increased. Effective gas production declined linearly (P =0.041; R² =0.085), whereas the slowly degradable fraction (P =0.042, R² =0.084), the fractional degradation rate (P =0.003, R² =0.175) and potential gas production (P =0.043, R² =0.083) showed quadratic trends as enzyme levels increased. Pre-treatment with Viscozyme reduced the fibre levels of GP and increased in vitro ruminal organic matter degradability. The optimum level for inclusion of Viscozyme was 5 g/kg.

Resumen Antecedentes: Los granos de cervecería son un subproducto de la industria cervecera que puede ser incluido en la dieta de rumiantes; sin embargo, su alta húmedad dificulta el almacenamiento y conservación de ese producto. Objetivo: Evaluar la eficiencia de la deshidratación al sol de los granos húmedos de cervecería (WBG) y el efecto del período de almacenamiento sobre su calidad nutricional y microbiológica. Métodos: Para evaluar la eficiencia de la deshidratación de los WBG se utilizó un diseño experimental completamente al azar, con tiempos de tratamiento de 0, 1, 2, 4, 6, 8, 10, 12, 14, y 16 horas de exposición al sol. En un segundo experimento, también con diseño experimental completamente al azar, se evaluó el efecto del almacenamiento comparando los siguientes tratamientos: 0, 10, 20, 30, 60, 90, 120, 150 y 180 días de almacenamiento del subproducto seco. Resultados: La materia seca (DM) del WBG presentó un efecto lineal creciente con el proceso de deshidratación. La composición química de los granos secos de cervecería no tuvo efecto en función de los tiempos de almacenamiento. La proteína no digestible (fracción C) aumentó linealmente; sin embargo, no comprometió la producción acumulativa de gas y la digestibilidad in vitro de la DM y de la proteína. El tiempo de almacenamiento no tuvo efecto sobre la población de hongos. El valor máximo de aflatoxina obtenido fue de 45,5 μg/kg y permaneció dentro de los limites aceptables para alimentación de bovinos. Conclusión: La deshidratación de WBG al sol es eficiente para garantizar la conservación del material y viabilizar su almacenamiento. El almacenamiento por 180 días de este subproducto seco no compromete su calidad nutricional y microbiológica.

Abstract Background: Brewer's grains, a by-product of the brewery industry, can be included in the diet of ruminants. However, its high humidity makes it difficult to store and preserve. Objective: To evaluate the efficiency of sun dehydration of wet brewer’s grains (WBG) and the effect of storage period on its nutritional and microbiological quality. Methods: A completely randomized experimental design was used to evaluate WBG dehydration efficiency, with treatments corresponding to 0, 1, 2, 4, 6, 8, 10, 12, 14 and 16 hours of sun exposure. A second experiment was carried out using also a completely randomizeddesign to evaluated the effect of storage with the following treatments: 0, 10, 20, 30, 60, 90, 120, 150 and 180 days of storage of the dry by-product. Results: Dry matter (DM) content linearly increased with dehydration period. The chemical composition of the dried brewer's grains had no effect as a function of storage period. Indigestible protein (C fraction) increased linearly but did not compromise the cumulative gas production and the in vitro digestibility of DM and protein. Storage time had no effect on fungus population. The maximum aflatoxin value was 45.5 μg/kg, and remained within acceptable limits for bovine feed. Conclusion: Dehydration of WBG in the sun is efficient to guarantee conservation and makes it possible to store the by- product. The storage of the dry by-product for 180 days does not compromise its nutritional or microbiological quality.

Resumo Antecedentes: Os grãos de cervejaria são um subproduto que podem ser incluídos na dieta de ruminantes, no entanto sua forma úmida dificulta o armazenamento e a conservação desse produto. Objetivo: Avaliar a eficiência de desidratação ao sol dos grãos úmidos de cervejaria (WBG) e o efeito do período de armazenamento sobre a qualidade nutricional e microbiológica. Métodos: Para avaliar a desidratação do WBG, utilizou-se um delineamento experimental inteiramente casualizado, sendo os tratamentos os tempos de 0 e 1, 2, 4, 6, 8, 10, 12, 14 e 16 horas de exposição ao sol. Um segundo experimento foi realizado em delineamento inteiramente casualizado. Os tratamentos foram 0, 10, 20, 30, 60, 90, 120, 150 e 180 dias de armazenamento do subproduto seco. Resultados: A matéria seca (DM) do WBG apresentou efeito linear crescente com o processo de desidratação. A composição química dos grãos secos de cervejaria não apresentou efeito em função dos tempos de armazenagem. A proteína indigestível (Fração C) aumentou linearmente, no entanto não comprometeu a produção cumulativa de gás e a digestibilidade in vitro da DM e da proteína. A população de fungos não apresentou efeito com o tempo de armazenamento. O valor máximo de aflatoxina obtido foi de 45,5 μg/kg e permaneceu dentro dos limites aceitáveis para a alimentação de bovinos. Conclusão: A desidratação do WBG ao sol foi eficiente em garantir a conservação do material e viabilizar o seu armazenamento. A estocagem desse subproduto seco por 180 dias não comprometeu a sua qualidade nutricional e microbiológica.

ABSTRACT Two studies were carried out to evaluate the effects of levels of soybean meal produced from damaged soybean grains replacing normal soybean meal on in vitro and in situ digestibility of ruminant diets as well as on intake, digestibility, and animal performance of growing/finishing lambs. In trial 1, we evaluated the in vitro digestibility of each soybean meals (normal and damaged), as well as diets containing levels of the damaged replacing the normal (0, 333, 667 and 1,000 g.kg−1) soybean meal on kinetic parameters of in vitro cumulative gas production, in vitro dry matter and crude protein digestibility, in situ rumen-degradable protein, rumen-undegradable protein, and in vitro intestinal digestibility of rumen-undegradable protein. In trial 2, we used 48 growing/finishing lambs to evaluate the effects of damaged soybean meal levels (0, 333, 667, and 1,000 g.kg−1) replacing normal soybean meal in feedlot diets (20:80 roughage:concentrate ratio) on intake and digestibility of nutrients and on animal performance. The damaged soybean meal presented lower values for total gas production and in vitro dry matter digestibility than normal soybean meal. Higher rumen-undegradable protein was estimated for damaged soybean meal than for the normal and consequently lower rumen-degradable protein for damaged compared to normal. Because of the lower rumen-degradable protein, damaged soybean meal promoted lower in vitro ammonium nitrogen (NH3-N) concentrations than the normal in feedlot diets. In the in vivo trial, there were no effects of damaged soybean meal levels in the diets on intake and digestibility of nutrients (dry matter, organic matter, crude protein, and fiber) as well as on total weight gain, average daily gain, carcass yield, or feeding efficiency. Thus, damaged soybean meal can fully replace the normal one in lamb feedlot diets (in up to of 1,000 g.kg−1 of the normal soybean meal) without causing adverse effects on intake and digestibility of nutrients and on animal performance.

RESUMO: Objetivou-se avaliar os modelos matemáticos Gompertz, Groot, monomolecular, Richards e logístico bicompartimental para estudar a cinética de produção de gás in vitro de dietas compostas de combinações de feno ou silagem de Gliricídia. Além disso, avaliou-se os efeitos da inclusão de feno ou silagem de Gliricídia sobre a produção cumulativa de gás in vitro destas dietas. A cinética de fermentação ruminal foi avaliada pela metodologia de produção cumulativa de gás in vitro. Os parâmetros dos modelos foram estimados usando o método de Gauss Newton, com exceção do modelo de Richards, que foi usado algoritmo de Marquardt. O ajuste dos modelos foi avaliado por meio do coeficiente de determinação, teste F para a identidade dos parâmetros, coeficiente de correlação e concordância, raiz quadrada do quadrado médio do erro da predição e a decomposição do quadrado médio do erro da predição em erro médio, vício sistemático e erro aleatório. Os modelos foram comparados quanto à acurácia (quadrado médio da predição pareado) e quanto à sua precisão (critério de informação delta de Akaike). Todas as estatísticas de avaliação e comparação dos modelos foram calculadas usando o software Model Evaluation System versão 3.2.2. Os modelos de Groot e Richards não diferiram entre si (P>0.05) e foram os mais precisos e acurados (P<0.05). Portanto, modelo de Groot foi selecionado devido apresentar melhor acurácia e precisão e apresentar maior facilidade na obtenção dos parâmetros. A inclusão da silagem de Gliricídia na dieta, resultou em elevação no tempo para obtenção da máxima taxa de degradação e no tempo após a incubação em que metade do nível assintótico foi atingido. Recomenda-se a utilização do modelo de Groot para estimativa da curva média. A inclusão da silagem de Gliricídia altera a curva de produção de gás devido o maior tempo necessário para que a dieta atingisse a máxima taxa de degradação, isso pode elevar o tempo de permanência da dieta no rúmen e promover redução no consumo.

ABSTRACT: This study examined the use of the Gompertz, Groot, monomolecular, Richards and two-compartment-logistic mathematical models to investigate the kinetics of in vitro gas production of diets composed of combinations of Gliricidia hay or silage. In addition, the effects of Gliricidia hay or silage inclusion on the in vitro cumulative gas production of these diets were evaluated. Rumen fermentation kinetics were analyzed by the in vitro cumulative gas production methodology. The model parameters were estimated using the Gauss Newton method, with the exception of the Richards model, which was used by Marquardt’s algorithm. Model fit was assessed using the determination coefficient, F test for parameters identity, concordance correlation coefficient, root mean square error of prediction, and decomposition of mean square error of prediction into mean error, systematic bias and random error. The models were compared for accuracy (pairwise mean square error of prediction) and precision (delta Akaike’s information criterion). All model evaluation and comparison statistics were calculated using Model Evaluation System software version 3.2.2. The Groot and Richards models did not differ from each other (P>0.05) and were the most precise and accurate (P<0.05). Therefore, the Groot model was selected due to its better accuracy and precision and easier access to the parameters. The inclusion of Gliricidia silage in the diet resulted in an increase in the time to obtain the maximum rate of degradation and in the time after incubation when half of the asymptotic level was reached. The Groot model is recommended to estimate the average curve. Dietary inclusion of Gliricidia silage alters the gas production curve due to the longer time required for the diet to reach the maximum rate of degradation, this can increase the time the diet remains in rumen and promote a reduction in the consumption.

ABSTRACT. Climate change (CC) affects food production, mainly those based on livestock systems. Producers must identify adaptation strategies to ensure the production, during periods of drought, and lack of forage. Besides contributing to CC, high emissions of ruminal methane (CH4) are energy loss potentially usable for livestock production. The objective was to estimate in vitro ruminal gas production (RGP) and determine the CH4 emissions from silages. Treatments were made with forage of Cenchrus purpureus mixed with Tithonia diversifolia T1= C.purpureus at 100%; T2= C.purpureus/ T.diversifolia in 33/67 percent ratio; T3= C.purpureus/ T.diversifolia 67/33; and T4= T.diversifolia at 100%. Samples of silages were analyzed, and they were inoculated with strains of Lactobacillus paracasei (T735); then they were fermented in vacuum-sealed bags for 67 days. RGP and CH4 were measured at 2, 4, 8, 12, 18, 24, 30, 36, and 48 hours. Additionally, modeling of CH4 production kinetics was conducted, using different equations. The results indicate that the highest cumulative CH4 production was for T1. This kinetics was represented using the Gompertz model. In conclusion, the inclusion of T.diversifolia to C.purpureus silages contributes to the decrease of methane at the ruminal level, which constitutes an adaptation practice at climate change.

RESUMO: Com a intensificação dos sistemas de produção e o aumento das exigências alimentares das vacas leiteiras criou-se a necessidade de diversificação nas opções de alimentos, focando em alternativas mais eficientes, modernas e sustentáveis. Poucas pesquisas foram realizadas avaliando a inclusão da farinha de batata-doce como fonte de energia em substituição ao milho para ruminantes. O objetivo deste trabalho foi avaliar a produção de gás in vitro da farinha de batata-doce (SPF) em substituição ao milho moído em diferentes níveis. Para a produção de gás in vitro, foram realizados quatro tratamentos, com substituição de milho por farinha de batata-doce a 0, 33, 66 e 100%, em uma dieta com silagem de milho, farelo de soja e milho moído. As incubações foram conduzidas em frascos selados contendo 50 ml do inóculo preparado utilizando o fluido ruminal, solução tampão e 0,5 g de cada tratamento. A produção de gás acumulada foi maior na substituição do milho pela SPF em 100% (224 ± 1.45 e 231,9 ± 1.45 ml/g MSi para as substituições 0 e 100%, P = 0,01). A taxa de degradação foi 7,10, 7,59, 8,08 e 8,59 ± 0,06% por hora nas substituições 0, 33, 66 e 100%, respectivamente (P<0,001). Houve também diferença (P = 0,002) no lag time, em que as dietas com maior inclusão de SPF tiveram tempo de colonização bacteriana menor. Em conclusão, a farinha de batata-doce produziu mais gás e foi degradada mais rapidamente que o milho.

ABSTRACT: With the intensification of production systems, dairy cow feeding has undergone changes creating the need to increase substitute feed options, focusing on more efficient, modern, and sustainable alternatives. Few researches were carried out evaluating the inclusion of sweet potato flour as an energy source in substitution of maize for ruminants. The aim of this study was to evaluate the in vitro gas production of ground corn replacement by sweet potato flour at different levels. For in vitro gas production, four treatments were performed, consisting of corn replacement by sweet potato flour at the levels of 0, 33, 66, and 100%, in a diet consisting of corn silage, soybean meal, and ground corn. In vitro incubations were conducted in sealed bottles containing 50 ml of the inoculum prepared using ruminal fluid and 0.5 g of each treatment. Gas production was determined in 96 consecutive hours. The cumulative gas production was greater when the corn was 100% replaced by SPF (224 ± 1.45 and 231.9 ± 1.45 ml/g DMi for 0 and 100% of replacement, P = 0.01). Degradation rates were 7.10, 7.59, 8.08, and 8.59 ± 0.06% per hour for the 0, 33, 66, and 100% replacement rates, respectively (P<0.001). There was also a difference (P = 0.002) in the lag time, in which diets with the highest SPF inclusion had a lower colonization time. In conclusion, sweet potato flour produced more gas and was more rapidly degraded than corn.

Exogenous enzymes and essential oils (EOs) have both improved fibre digestion in ruminants, but the effect on ruminal fermentation and methane emission of combining these additives requires further evaluation. Various EOs were used in combination with an enzyme in an in vitro gas production system to measure organic matter digestibility and methane after 48 hours of incubation of Eragrostis curvula. The treatments consisted of T1) unaugmented control; T2) enzyme (cellulose-xylanase mixture, 1:1 w/w, 1.5 mL/g DM); T3) enzyme combined with Next Enhance® (cinnamaldehyde with diallyl disulfide and diallyl trisulfide, 43:3.85 w/wt); T4) enzyme and cinnamon oil; T5) enzyme and garlic oil; and T6) enzyme with cinnamon and garlic oil, 1:1 w/w). At 2, 4, 8, 12, 24, 36, and 48 hours of incubation, gas production was measured, and gas samples were analysed for methane concentration. The inclusion of additives affected cumulative gas production (P <0.05), but only slightly affected methane production (P =0.05) after 48 hours of incubation. The addition of enzymes increased both gas and methane production. T5 and T6 both reduced gas production compared with T2. Combining EOs with an enzyme reduced methane production compared with T2 after 48 hours of incubation. The additives tended to increase in vitro organic matter digestibility (P =0.09), although they showed a tendency towards reduced methane production per unit of organic matter digested (P =0.07). Further studies on these enzyme and EO combinations under different doses and substrates are required to validate their efficacy for ruminant production.

RESUMO: Técnicas de produção de gás in vitro representam uma ferramenta valiosa para descrever a cinética de degradação ruminal dos alimentos. No entanto, o líquido ruminal utilizado como inóculo microbiano tem sido uma grande fonte de variação e erro. A padronização deste fator deve contribuir para garantir a independência dos parâmetros de fermentação dos alimentos a partir dos inóculos. Neste trabalho, hipotetizou-se que um tratamento controlado de pré-incubação do líquido ruminal poderia contribuir para estabilizar e homogeneizar os resíduos não digeridos dos brancos e, como conseqüência, da produção de produção cumulativa de gás residual (CGP). Uma pré-incubação (ou seja, incubação real prévia) dos inóculos do rúmen foi desenvolvida com um substrato simples semelhante à dieta oferecida aos doadores a 1% p/v por 0, 1, 2 e 4 h (Controle, Prei-1, Pré- 2 e Prei-4 tratamentos respectivamente). Uma vez completadas as horas de pré-incubação, elas foram incubadas com substratos contrastantes e sem substrato (ou seja, brancos) para avaliar o CGP, a digestibilidade in vitro da MS e os produtos de fermentação. Embora a atividade fermentativa dos inóculos pré-incubados tenha funcionado satisfatoriamente no sistema in vitro, ao contrário do que foi especulado, os resíduos da pré-incubação aumentaram a variabilidade e heterogeneidade das variâncias entre os brancos. Consequentemente, concluiu-se que as pré-incubações não funcionaram para gerar um líquido ruminal mais homogêneo e menos variável para o sistema de produção de gás in vitro.

ABSTRACT: In vitro gas production techniques represent a valuable tool to describe the kinetics of ruminal degradation of food. However, the ruminal liquor used as a microbial inoculum has been a great source of variation and error. A standardization of this factor should contribute to assure the independence of food fermentation parameters from those of the inocula. In this research it was hypothesized that a controlled pre-incubation treatment of ruminal liquor could contribute to stabilize and homogenize the undigested residues of blanks and as a consequence, of the production of residual cumulative gas production (CGP). A pre-incubation (i.e. previous real incubation) of rumen inocula was developed with a simple substrate similar to the diet offered to donors at 1% w/v for 0, 1, 2 and 4 h (Control, Prei-1, Prei-2 and Prei-4 treatments respectively). Once the pre-incubation hours were completed, they were incubated with contrasting substrates and without substrate (i.e. blanks) in order to evaluate the CGP, in vitro digestibility of the DM and fermentation products. Although, the fermentative activity of the pre-incubated inoculums worked satisfactorily in the in vitro system, contrary to what was speculated, residues of the pre-incubation increased the variability and heterogeneity of variances among blanks. Consequently, it was concluded that the pre-incubations did not work to generate more homogeneous and less variable ruminal liquor for the in vitro gas production system.

ABSTRACT We evaluated the inclusion of two crude extracts produced by Streptomyces genus on in vitro dry matter and organic matter digestibility (IVDMD; IVOMD), cumulative gas production, volatile fatty acids (VFA), and methane (CH4) and ammoniacal nitrogen (NH3-N) concentration. The experimental design was randomized blocks with three blocks and four treatments: AMC (1.2 mg/25 mL ruminal inoculum), Caat (1.2 mg/25 mL ruminal inoculum), negative control (no inclusion of extracts), and positive control (sodium monensin, 1.7 mg/25 mL ruminal inoculum). Ruminal fluid samples were collected from three multiparous Holstein dairy cows fitted with ruminal cannula and incubated in a 24-h fermentation assay. There was no effect of crude extract inclusion in comparison with negative control on cumulative gas production in 24 h. However, cumulative gas production was lower when Caat extract was included in comparison with AMC inclusion. The Caat inclusion increased propionic acid concentration and reduced the concentration of butyric acid and acetate:propionate (A:P) ratio in relation to negative control. The CH4 concentration was lower with Caat inclusion in relation to AMC, and the ratio of CH4 concentration to digestible dry matter was lower in the negative control compared with all additives. Caat inclusion decreased the NH3-N concentration, and IVDMD was not altered compared with negative control. Additionally, the inclusion of Caat crude extract increased propionic acid concentration and reduced butyric acid concentration and A:P ratio, without reducing the IVDMD and IVOMD. Caat extract modulates rumen fermentation, increasing available energy and decreasing gas production without causing changes in dry matter and organic matter digestibility.

Abstract Most of the greenhouse gas (GHG) emissions from livestock production is attributed to ruminants. As a consequence of its warming potential, methane is the most important GHG, and different strategies have been implemented to reduce its emissions, including finding out the amount of GHG in the diets. Therefore, the objective of this study was to determine the in vitro effect of dried corn distillers grains with solubles (DDGS) on rumen fermentation, total biogas, and methane (CH4) and carbon dioxide (CO2) emissions in diets for lambs. The in vitro degradation of dry matter (DIVMS), pH, molar concentration of volatile fatty acids (AGV), and total bacteria count were determined after 72 h of incubation; meanwhile, the production of biogas, CH4, and CO2 was determined after 24, 48, and 72 h of fermentation of the three diets containing 0, 20, and 40 % DDGS based on the dry matter (MS). The DIVMS was higher (p≤0.05) in the 0 % GSDM diet. No differences (p>0.05) in pH, total bacteria, and AGV concentration were found among treatments. The total biogas production was higher (p≤0.05) in 40 % DDGS diet. The cumulative CH4 production was lower (p≤0.05) by 20 % DDGS diet compared to 0 % DDGS diet, and the cumulative CO2 production was higher (p≤0.05) in 40 % DDGS diet. Including 20 or 40 % of DDGS in diets for lambs reduces cumulative CH4 production, without affecting the rumen fermentation variables; however, including 40 % of DDGS increases the production of total biogas and CO2.

Resumen La mayoría de las emisiones de gases con efecto invernadero (GEI) provenientes de la producción pecuaria se atribuye a los rumiantes. El metano es el GEI más importante por su potencial de calentamiento y hay diferentes estrategias para disminuir sus emisiones, una de las cuales es conocer la cantidad de GEI en las dietas. Por lo tanto, el objetivo de este estudio fue determinar el efecto in vitro de los granos secos de destilería de maíz más solubles (DDGS, sigla en inglés) en la fermentación ruminal, biogás total, emisiones de metano (CH4) y dióxido de carbono (CO2) en dietas para corderos. La degradación in vitro de la materia seca (DIVMS), pH, concentración molar de ácidos grasos volátiles (AGV) y número total de bacterias se determinaron después de 72 h de incubación, y la producción de biogás, CH4 y CO2 a las 24, 48 y 72 h de fermentación de las tres dietas que contenían 0, 20 y 40 % de DDGS en base a la MS. La DIVMS fue mayor (p≤0.05) en la dieta con 0 % GSDM. No hubo diferencias (p>0.05) en pH, bacterias totales y concentración de AGV entre tratamientos. La producción total de biogás fue mayor (p≤0.05) en la dieta con 40 % de DDGS. La producción acumulada de CH4 fue menor (p≤0.05) en la dieta con 20 % de DDGS respecto a la dieta con 0 % de DDGS, y la producción acumulada de CO2 fue mayor (p≤0.05) en la dieta con 40 % de DDGS. La inclusión de 20 o 40 % de DDGS en las dietas para corderos reduce la producción acumulada de CH4, sin afectar las variables de fermentación ruminal, pero la inclusión de 40 % de DDGS incrementa la producción de biogás total y CO2.

ABSTRACT This study evaluated the influence of coastcross hay substrate hydration and equine fecal inoculum dilution on the parameters of fermentation and microbiology in in vitro essays. A 2 × 2 factorial block design was used. The first factor was hydration of the coastcross hay substrate 12 h before incubation or at the time of incubation, and the second factor was the dilution of fecal inoculum with a nutrient solution in a weight: weight ratio of 1:1 or 1:3. Degradation of the dry matter (DM), organic matter (OM), and neutral detergent fiber (NDF) were evaluated at 24, 48, and 72 h. Microorganisms were counted 24 h after inoculation. The ammoniacal nitrogen concentration (NH3-N), pH, and cumulative gas production were measured up to 72 h and adjusted by the non-linear Gompertz regression model. Hydration of substrate and time of incubation increased nutrient degradation of coastcross hay, as well as the final volume of gases and the concentration of Streptococcus spp. The 1:3 dilution increased the final pH and Streptococcus spp. concentration. The hydration of substrate did not have any effect on NH3-N, Lactobacillus spp., cellulolytic, and total anaerobic bacteria concentrations. In addition, no effect of hydration was observed on the fermentation rate and the maximum fermentation time on the model used. The fermentation profile of the grass substrate is not affected by dilution, and, therefore, horse feces can be used as a source of inoculum in in vitro fermentation trials. Hydration increases the gas volumes and the nutrient degradation of grass hay, renders the lag phase time insignificant and, therefore, can be irrelevant in terms of fermentation model settings.