Four Holstein steers (297 ± 56 kg of body weight (BW)) fitted with duodenal cannula and rumen catheter, were housed in metabolism cages and used in a 4 × 4 Latin Square trial to evaluate the effect of both protein source and Acacia mearnsii tannin extract on digestibility, ruminal fermentation, rumen microbial protein synthesis, N utilization and on duodenal flow of individual amino acids. The diet was offered at restricted amount of 25 g of dry matter (DM)/kg BW and consisted of maize silage plus concentrate, in a proportion of 0·7:0·3 (DM basis) respectively. Concentrate was formulated with either soybean meal or canola meal as protein source, with or without 50 g/ kg of A. mearnsii tannin extract (i.e. 15 g/kg of total dietary DM). There was no effect of protein source on most variables. The apparent and true organic matter (OM) digestibilities, as well as neutral detergent fibre (NDF) digestibility were negatively affected by tannin extract inclusion without, however, affecting digestible OM intake. The amount of nitrogen (N) excreted in faeces increased whereas the urinary N excretion decreased in tannin extract treatments. No interaction time × treatment was detected for any rumen variable and no treatment effect was observed for rumen fluid pH and reducing sugars concentration. Rumen fluid concentration of ammonia N was lower for the canola meal plus tannin extract treatment. Rumen concentration of α-amino compounds was not affected by tannin extract but was higher when canola meal was the protein source. The duodenal flow of OM, total N, α-amino N and non-ammonia non-microbial N increased with tannin extract inclusion, whereas the duodenal flow of microbial N was not affected by treatment. For both protein sources, the amount of most individual amino acids flowing to the duodenum increased due to tannin extract addition. In conclusion, the dietary inclusion of 15 g/kg DM of tannin extract from A. mearnsii improved the amino acid supply independently of whether the protein source was canola meal or soybean meal, without affecting the amino acid profile, to steers fed maize silage plus concentrate, with a minor but significant impact on OM digestibility.
SUMMARYA set of independent assays were conducted to assess the effects of either pH or glucose concentration on forage degradation, bacterial adherence and on fibrolytic enzyme activityin vitro. For measuring degradation and bacterial adherence, ryegrass (Lolium multiflorum) and bermudagrass (Cynodon dactylon) samples were incubatedin vitrofor 24 h in the medium at different pH (5·5, 6·0, 6·5 or 7·0) or with different initial glucose concentrations (0, 1000, 2000 and 3000 mg/l). For fibrolytic enzyme activity evaluation, forage samples were incubatedin situand the extracted enzymes were incubatedin vitrounder the different pH and glucose treatment conditions. The amount of bacteria adhering to samples and the degradability of dry matter (DM) and neutral detergent fibre (NDF) were higher for ryegrass than for bermudagrass, were not affected by glucose concentration and were linearly and positively affected by increased pH. On average, carboxymethylcellulase (CMCase) and xylanase activities were higher for ryegrass than for bermudagrass in the pH assay, whereas the differences between forages were not significant in the glucose assay. For both forage species, the quadratic effect of pH or glucose concentration on CMCase and xylanase activities was significant. Maximum activity of both enzymes was observed at pH 6·0 or at glucose concentration of 2000 mg/l. In conclusion, forage degradation was affected negatively by decreased ruminal pH due to reduced bacterial adherence. In turn, the pH or glucose effect on fibrolytic enzyme activity was not related to their effects on bacterial adherence or forage degradation, indicating that forage degradation is more dependent on the degree of microbial colonization than on the specific activity of bacterial enzymes.
Inclusion of forage legumes in diet may improve tropical ruminant systems productivity and sustainability. However, it is not well stablished which chemical components more impact their nutritional value. The relationship between chemical composition and in vitro fermentation of tropical forage legume was evaluated with the objective of obtaining indicators of their nutritional value. Samples of Crotalaria spectabilis, Cajanus cajan, Macrotyloma axillare, Mucuna aterrina, Stylosantis sp. and Canavalia ensiformis, cut from plants at growth age between 47 to 110 days, were analysed. Total gas production showed negative correlation (P<0.05) with total N (R=-0.51), acid detergent fibre (ADF, R=-0.62) and acid detergent lignin (ADL, R=-0.65), and positive correlation with non-fibre carbohydrates (NFC, R=0.70). Gas production rate was negatively related (P<0.05) to NDF (R=-0.73), ADF (R=-0.62) and ADL (R=-0.74). Ammonia concentration in the incubation medium was positively related (P<0.05) to total (R=0.74) and soluble (R=0.56) N, and negatively related to NFC (R=-0.81). The level of bacterial adhesion on residue of incubation was negatively related (P<0.05) to cell wall components, mainly to ADL (R=-0.57). The inclusion of polyehtylene glycol increased both gas volume and gas production rate whereas decreased ammonia concentration (P<0.05). In conclusion, even at low concentrations tannins impact the in vitro fermentation of tropical legumes. However, among the analyzed chemical components, the ADL was the best indicator of the nutritional value of the tropical forage legumes.Index terms: Gas production, lignin, nutritional value, phenolic compounds, tannins. RESUMOA inclusão de leguminosas na dieta tem o potencial de melhorar a produtividade e sustentabilidade dos sistemas de produção de ruminantes em regiões tropicais. Contudo, não está bem estabelecido quais componentes químicos são os mais determinantes do seu valor nutricional. Este estudo avaliou a relação entre componentes químicos e a digestão in vitro de leguminosas forrageiras tropicais, com o objetivo de obter indicadores de seu potencial nutricional. Foram incluídas amostras de Crotalaria spectabilis, Cajanus cajan, Macrotyloma axillare, Mucuna aterrina, Stylosantis sp. e Canavalia ensiformis cortadas de plantas com idades de crescimento entre 47 a 110 dias. O volume de gases apresentou correlação negativa (P<0,05) com os teores de N (R=-0,51), fibra em detergente ácido (FDA, R=-0.62) e lignina em detergente ácido (LDA, R=-0,65), e positiva com o teor de carboidratos não fibrosos (CNF, R=0,70) das leguminosas. A taxa de produção de gases foi negativamente relacionada (P<0.05) com os teores de FDN (R=-0.73), FDA (R=-0.62) e LDA (R=-0.74). A concentração de amônia no meio foi positivamente correlacionada (P<0.05) com o teor de N total (R=0.74) e N solúvel (R=0.56) e, negativamente, correlacionada com o teor de CNF (R=-0.81). O grau de aderência bacteriana no resíduo de incubação foi negativamente relacionada (P<0.05) com os componentes da parede cel...
The objective of this study was to analyse the sustainability of different livestock systems in the Brazilian Pampa biome, from the perspective of the rangeland dilemma. We used the indicator-based framework for evaluating the sustainability of natural resource management systems (MESMIS). These were constructed for social, economic and environmental dimensions, and they were measured across a study suite of 115 establishments, representing the rangeland livestock system (RLS), intensive livestock system, and livestock–agricultural system (ALS). Indicator averages were compared between three systems via ANOVA and Tukey test. The results allocated a higher level of sustainability to RLS. When the three land-use systems were analysed across the dimensions, significant differences were found in their environmental sustainability, with the ALS presenting poorer results. Within each dimension, there were significant differences in the indicators for production systems, social participation and capital flow. We discussed two main points: the results found through the concept of the rangeland dilemma, by exploring its conditions, in addition to exposing the concept of functional integrity. In conclusion, an approach to develop policies for the Pampa is to recognize the rangeland as a “common good”, to generate income and stimulate the local economy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.