Synthesis and role of melanin for tolerating in vitro rumen digestion in Duddingtonia flagrans, a nematode-trapping fungus.

We describe the synthesis and a function of melanin in Duddingtonia flagrans, a nematode-trapping fungus. We tested various culture media treated with L-DOPA, glucose and tricyclazole on fungal growth and melanin distribution using infrared spectroscopy (IS), electron paramagnetic resonance (EPR) and transmission electron microscopy (TEM). In vitro rumen digestion was used to test the environmental stress and then to evaluate the capacity of this fungus to trap nematode larvae. The growth and melanization of the fungus after 21 days of incubation at 30°C were best in Sabouraud dextrose medium. IS indicated the presence of melanin in D. flagrans, with similar bands for commercial melanin used as a control, and assigned the values obtained by EPR (g of 2.0051 ± 0.0001) to the production of melanin by the fungus. TEM indicated that melanin was produced in melanosomes but was not totally inhibited by tricyclazole. Within the limits of experimental error, the predatory activity of fungus treated with tricyclazole was drastically affected after 27 h of in vitro anaerobic stress with rumen inoculum. The deposition of melanin particles on the fungal cell wall contributed to the maintenance of D. flagrans predatory abilities after in vitro anaerobic ruminal stress.

First record of the nematode Libyostrongylus dentatus Hoberg, Lloyd & Omar, 1995 (Trichostrongylidae) in ostriches (Struthio camelus Linnaeus, 1758) (Struthionidae) outside the Americas.

BACKGROUND: Libyostrongylus douglassii, Libyostrongylus dentatus and Libyostrongylus magnus are nematodes that infect ostriches. The first species has been identified in ostriches from Africa, Europe, Americas and Oceania. Although the natural range of ostriches is Africa, L. dentatus was first described in birds from the USA and later identified in Brazil, where co-infections with L. douglassii have been commonly reported. Libyostrongylus magnus is known from the original description only. There are a few reports on infections with L. douglassii in ostriches from Africa and all farmed birds examined are from the southern region of the continent. The aim of this report was to verify Libyostrongylus spp. infections in wild ostriches from Ethiopia. Fecal samples from ostriches, Struthio molybdophanes, were collected and submitted to coproculture. Infective larvae were identified to the species level based on general morphology and morphometry. In addition, phylogenetic analysis of the first and second internal transcribed spacer (ITS1 and ITS2) of the nuclear ribosomal DNA was performed. RESULTS: Infective larvae from Ethiopian ostriches had the morphological characteristics of L. dentatus. Confidence interval estimate for sheath tail length from Ethiopian Libyostrongylus sp. isolates overlapped one for Brazilian L. dentatus. Neighbor-joining and Maximum Likelihood phylogenetic trees based on sequences of the ITS1 and ITS2 regions revealed that the Ethiopian samples belong to the L. dentatus species clade. Monospecific infections with L. dentatus were confirmed in Ethiopian wild ostriches, opposed to the co-infections typically found in the Americas. CONCLUSIONS: To our knowledge, this is the first record of L. dentatus from African ostriches, the region from which this parasite originated.

Intake and performance simulation of goats fed exclusively tifton 85, mulberry or leucaena / Simulação do consumo e do desempenho de caprinos alimentados exclusivamente com tifton 85, amoreira e leucena

Intake and performance of goats fed exclusively forages Tifton 85, mulberry or leucaena were simulated to verify which nutrients limit performance. Simulations were performed using the nutritional model similar to Cornell Net Carbohydrate and Protein System (CNCPS) with modifications related to the kinetic attributes of digestion and feed passage. The animal category chosen to perform the simulations was female Saanen goats in growing phase between weaning and mating, with 20 kg of body weight and 150 g of daily gain. The intake of 0.870 kg/day of Tifton 85 was adopted for performance simulations because in this point caused rumen fill and also attended the energy requirement of the animal. For performance simulations of mulberry, the amount of dry matter intake of 0.580 kg/day was adopted based on average intake obtained from the study of Sabino Jr. (1996) and simulations for leucaena used the intake of 0.220 kg/day, corresponding to 30g/100g of dry matter intake that would supply the energy requirement of these female goats. The limiting factor of performance of Saanen female growing goats fed exclusively Tifton 85 or mulberry is the metabolizable protein and not the energy. The intake of leucaena exclusively would be able to supply the requirement of metabolizable protein to promote the target weight gain of 150 g/day. The forages do not present perfect synchronization between carbohydrates and proteins, demonstrated by the positive ammoniacal balance in rumen environment that indicates an excess of nitrogen compounds supplied by these feed.

Simulações de consumo e desempenho de caprinos alimentados exclusivamente com as forrageiras Tifton 85, amoreira e leucena foram realizadas para verificar quais nutrientes seriam limitantes para o desempenho. Assimulações foram feitas utilizando o modelo similar ao Cornell Net Carbohydrate and Protein System (CNCPS) com algumas modificações em relação à cinética de digestão e passagem do alimento. A categoria animal escolhida foi a de cabritas Sannen em fase de crescimento entre o desmame e a puberdade, com 20 kg de peso corporal e ganho médio diário de 150 gramas por dia. Foi adotado o consumo de 0,870 kg/dia de Tifton 85 para realizar as simulações de desempenho, porque nesse ponto ocorreria repleção ruminal e ao mesmo tempo atenderia a demanda de energia do animal. Para simulações de desempenho da amoreira, foi adotada o consumo de matéria seca de 0,580 kg/dia obtido em estudo de Sabino Jr. (1996) e para as simulações com a leucena foi usado o consumo de matéria seca de 0,220 kg/dia, que corresponde à quantidade que iria suprir o requerimento de energia desses animais. O principal fator limitante do desempenho de fêmeas Saanen em crescimento alimentadas exclusivamente com Tifton 85 ou amoreira é a proteína metabolizável e não a energia. O consumo exclusivo de leucena seria capaz de suprir o requerimento de proteína metabolizável para promover ganho médio diário de 150 g/dia. As forrageiras não apresentaram perfeita sincronização entre carboidratos e proteína, verificado pelo balanço amoniacal positivo no rúmen, que indica excesso de nitrogênio desses alimentos.

Clitoria ternatea L. as a Potential High Quality Forage Legume.

Samples of Clitoria ternatea L. (Cunhã) were harvested at 35, 50, 70, and 90 d after a uniformity harvest in a field study designed as a completely randomized design with a total of 18 experimental plots. The dry matter yield of the whole plant was separated quantitatively into leaves, stems, and pods at each harvesting age. Chemical analyses and in vitro gas production kinetics were performed to assess the quality of the plant parts. Yields, chemical composition, and estimates of gas production parameters were analyzed by fitting a mixed statistical model with two types of covariance structures as follows: variance components and an unrestricted structure with heterogeneous variances. Fast and slow gas yielding pools were detected for both leaves and stems, but only a single pool was detected for pods. The homoscedasticity assumption was more likely for all variables, except for some parameters of the gas production kinetics of leaves and stems. There was no presence of typical pods at 35 and 50 d. In the leaves, the fibrous fractions were affected, whereas the non-fibrous fractions were unaffected by the harvesting age. The harvesting age affected the majority of the chemical constituents and gas kinetic parameters related to the stems. The leaves of this legume were the least affected part by the aging process.

Population dynamics of Libyostrongylus dentatus and L. douglassii of ostriches raised in the Northern Rio de Janeiro State, Brazil.

Libyostrongylus genus contains three species of gastrointestinal nematodes that infect ostriches. Of these, only Libyostrongylus douglassii has been implicated in diseases and lower productivity. A morphological diagnosis method allowing the discrimination of infective larvae of L. douglassii and Libyostrongylus dentatus and the evaluation of eggs per gram of feces (EPG) was used to determine the population dynamics of both species from two ostrich farms located in the northern region of the state of Rio de Janeiro, Brazil. The presence of these nematodes was monitored every 15 days for two years. The average EPG was 4631 and 587 on farms 1 and 2, respectively. Overall, the highest values of EPG were associated with the rainy season on both farms. However, only on farm 1 the rainy season correlated statistically with EPG. Both species of Libyostrongylus occurred on both farms with a higher predominance (86%) of L. douglassii on farm 1, whereas the distribution of infection on farm 2 was more heterogeneous with a slight predominance of L. douglassii. The infection and the prevalence of these species may vary considerably according to the farm facilities, management adopted, and season.

In vitro degradation kinetics of protein and carbohydrate fractions of selected tropical forages / Cinética de degradação in vitro das frações de proteína e carboidrato em forrageiras tropicais

Whereas obtain detailed information about nutrient composition and degradation rates of carbohydrate and protein fractions of tropical forages is essential to determine how much of each nutrient can be used by the animal and the main limiting causes to the level of production. A descriptive study was conducted to evaluate the degradation rate of protein and carbohydrate fractions and understand degradation synchronism of carbohydrates and protein fraction in the rumen of goats fed Tifton 85, mulberry and leucaena forages. Contents of crude protein (CP), nonprotein nitrogen (NPN), neutral detergent insoluble nitrogen (NDIN) and acid detergent insoluble nitrogen (ADIN) were measured to obtain the protein fractions A, B1, B2 and C. Degradation profiles of nitrogen fractions were obtained in vitro incubating the forages samples with proteases from Streptomyces griseus. Contents of sugars, starch and soluble fiber (neutral detergent NDSF) were analyzed to determine the fractions A and B1 from total carbohydrates (TC), whereas for fraction B2, C and degradation rate of fraction B2, the gravimetric technique of in vitro degradation of the fiber was used through kinetic interpretation of degradation profiles. It was adopted descriptive statistics to summarize the dataset, to describe the data, tables were compiled and used sample average as position measurement. Regarding Tifton 85, the sum of fractions A and B1 was 51.61 g/100g CP and the fraction B2 was 38.74 g/100g CP. Thus, the portion of slowly degradable protein from this forage is higher and tends to escape from rumen contributing with amino acids in the small intestine. Differently, most of the protein from mulberry and leucaena are present as highly degradable protein in rumen (B1), requiring supplementation with readily fermentable carbohydrate for a better utilization of nitrogen compounds. Considering the partitions of protein in different compartments of the plant, possibly the mixture between forages promotes a better balance for the use of this nutrient by animals. Fractions representing about 80g/100g of the protein from Tifton 85 presents problems to be used by animals. This means that, despite the high levels of protein in Tifton 85, metabolizable protein deficit may occur at any time after the intake of forages by the animals. Mulberry and leucaena are extremely degradable feed, both for cellular content and cell wall, with high possibility of presenting good synchronization between degradation of carbohydrate and protein.

A obtenção de informações detalhadas sobre a composição dos nutrientes e a taxa de degradação das frações de carboidratos e proteínas é essencial para determinar quanto de cada nutriente pode ser usado pelo animal e quais as principais limitações para o nível de produção. Um estudo descritivo foi conduzido para avaliar a taxa de degradação das frações de carboidratos e proteína e compreender o sincronismo de degradação dessas frações no rúmen de cabras alimentadas com as forrageiras Tifton-85, amoreira e leucena. Os conteúdos de proteína bruta (PB), nitrogênio não protéico (NNP), nitrogênio insolúvel em detergente neutro (NIDN) e nitrogênio insolúvel em detergente ácido (NIDA) foram mensurados para obter as frações de protéicas A, B1, B2 e C. O perfil de degradação das frações de nitrogênio foram obtidas por incubação das forragens com proteases de Streptomyces griseus. Os conteúdos de açúcares, amido e fibra solúvel em detergente neutro (FSDN) foram analisados para determinar as frações A e B1 dos carboidratos totais (CT), sendo que para obtenção da fração B2, C e para taxa de degradação da fração B2, a técnica gravimétrica de degradação da fibra in vitro foi utilizada através da interpretação do perfil cinético de degradação. Foi utilizada a estatística descritiva para analisar os dados e como medida de posição foi adotada a média. Em relação ao Tifton 85, a soma das frações A e B1 foram 51.61 g/100g PB e a fração B2 foi 51.61 g/100g PB. Portanto, as frações de proteína de baixa degradação dessa forrageira são altas e tendem a escapar do rúmen e contribuir com aminoácidos no intestino delgado. Por outro lado, a maior parte da proteína da amoreira e leucena são altamente degradáveis no rúmen (B1), o que requer suplementação com carboidratos rapidamente fermentáveis para melhor utilização dos compostos nitrogenados. Considerando as partições da proteína nas diferentes partes da planta, é possível que a mistura entre essas forrageiras permita um melhor balanceamento para uso desse nutriente pelos animais. Cerca de 80g/100g de proteína do Tifton 85 apresentaram problemas de uso pelos animais. Isso significa que, apesar do alto nível de proteína nessa forrageira, deficiência de proteína metabolizável pode ocorrer em algum momento. Amoreira a leucena são alimentos com alta degradação, tanto do conteúdo celular como da parede celular, com alta possibilidade de apresentar boa sincronização entre a degradação de carboidratos e proteína.

A generalized compartmental model to estimate the fibre mass in the ruminoreticulum: 1. Estimating parameters of digestion.

Parameters related to the microbial digestion of nutrients in the ruminoreticulum have been estimated by fitting mathematical models to degradation profiles generated from kinetic studies. In the present paper, we propose a generalized compartmental model of digestion (GCMD) based on implicit theoretical concepts and the gamma probability density function to estimate fibre digestion parameters. The proposed model is consistent to a broader compartmental model presented in a companion paper that integrates aspects of fibre digestion and passage. Different versions of the GCMD were generated by increasing the integer order of time dependency of the gamma function. These versions were fitted to 192 published fibre degradation profiles that were obtained using an in vitro fermentation technique. The quality of fit was evaluated based on the frequency of minimum sum of squares of errors (SSE), the number of runs of signs of residuals, and its likelihood probability calculated according to the Akaike's Information Criterion. The likelihood of the proposed model was also compared to a discrete lag time model (DLT), which is commonly used to interpret fibre degradation profiles. The GCMD had superior quality of fit compared to the DLT and was considered more likely in describing 68.75% of the profiles evaluated. Only 9.38% of the degradation profiles that were fitted to the DLT model had a lower SSE. Even though the degradation profiles studied were generated by incubating feed samples up to 96h, the true asymptotic limit of fibre degradation can only be achieved by long-term fermentations. This fact leads to questioning the uniformity of the potentially digestible fibre fraction and a further approach based on GCMD-type model was used to account for its heterogeneous nature.

A generalized compartmental model to estimate the fibre mass in the ruminoreticulum: 2. Integrating digestion and passage.

Models used to predict digestibility and fill of the dietary insoluble fibre (NDF) treat the ruminoreticular particulate mass as a single pool. The underlying assumption is that escape of particles follows first-order kinetics. In this paper, we proposed and evaluated a model of two ruminoreticular sequential NDF pools. The first pool is formed by buoyant particles (raft pool) and the second one by fluid dispersed particles (escapable pool) ventrally to the raft. The transference of particles between these two pools results from several processes that reduce particles buoyancy, assuming the gamma distribution. The exit of escapable pool particles from the ruminoreticulum is exponentially distributed. These concepts were evaluated by comparing ruminoreticular NDF masses as 43 and 27 means from cattle and sheep, respectively, to the same predicted variable using single- and two-pools models. Predictions of the single-pool model were based on lignin turnover and the turnover associated to the descending phase of the elimination of Yb-labelled forage particles in the faeces of sheep. Predictions of the two-pool model were obtained by estimating fractional passage rates associated to the ascending and descending phases of the same Yb excretion profiles in sheep faeces. All turnovers were scaled to the power 0.25 of body mass for interspecies comparisons. Predictions based on lignin turnover (single pool) and the two-pool model presented similar trends, accuracies and precisions. The single-pool approach based solely on the descending phase of the marker yielded biased estimates of the ruminoreticular NDF mass.

Exigência de lisina para codornas japonesas (Coturnix japonica) na fase de cria / Lysine requirement for growing japanese quails (Coturnix japonica)

Foram utilizadas 400 codornas fêmeas com peso médio de 7,3g + 0,3g no período de um a 42 dias de idade. O delineamento experimental foi o inteiramente casualizado, com cinco tratamentos e quatro repetições com 20 aves por unidade experimental. Os tratamentos consistiram em cinco níveis de lisina total na ração (0,90 por cento; 1,05 por cento; 1,20 por cento; 1,35 por cento; 1,50 por cento). As características avaliadas foram: consumo de ração médio diário (g/ave/dia) e acumulado (g/ave/período); peso médio das aves (g), ganho em massa corporal acumulado (g/ave/período), conversão alimentar (g de ração consumida/g de ganho de peso), mortalidade ( por cento/período) e uniformidade ( por cento/período). Também foi descrita a curva de crescimento das codornas para cada nível de lisina total utilizado. Não foi verificado efeito significativo para nenhuma das características avaliadas (P>0,05). O nível de 0,90 por cento de lisina total em rações com 20,70 por cento de proteína bruta atendeu às exigências de codornas japonesas durante o período de crescimento, correspondendo a um consumo diário, por ave, de 96,9 mg de lisina total.

In a study to establish total lysine requirement for growing japanese quails, 400 female quails 7.3 g + 0.3 g mean body weight were used from one to 42 days of age. A completely randomized experimental design was adopted, with five treatments and four replicates, with 20 birds per experimental unit. The treatments were five total lysine levels in the diet (0.90 percent; 1.05 percent; 1.20 percent; 1.35 percent and 1.50 percent). The evaluated data were: daily feed intake (g/ bird/ day); total feed intake (g/ bird/ period); body weight (g/ bird); total body weight gain (g/ bird/ period); feed conversion rate (g of feed intake / g of weight gain); mortality ( percent / period) and uniformity ( percent / period). The growing curve of the quails fed each total lysine level studied was also described. There was no statistical significant effect for all the evaluated data (P > 0.05). The level of 0.90 percent total lysine in 20.70 percent crude protein diet met the requirement of japanese quails during growing period, equivalent to a daily total lysine intake of 96.9 mg/ bird.

Variação anual da composição bromatológica de duas forrageiras cultivadas nas baixadas litorâneas do Estado do Rio de Janeiro, Brasil / Variation on the annual nutritive value of two grasses cropped in the litoral lowlands of the State of Rio de Janeiro, Brazil

Análises de matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), lignina (LIG), frações de carboidratos e de compostos nitrogenados foram realizadas em capins provenientes de três propriedades rurais da região das baixadas litorâneas do Estado do Rio de Janeiro. Amostras do capim hemártria (HEM) (Hemarthria altissima) e do capim elefante (Pennisetum purpureum), utilizado como capineira (CEC) e sob pastejo rotacionado (CEP) foram coletadas mensalmente, ao longo das estações do ano agrícola de 1997 e 1998. Foram observados efeitos da estação do ano sobre a forrageira e entre forrageiras dentro de uma estação do ano. A quantidade de PB variou de 37,2g kg-1 de MS no CEC a 131,5g kg-1 de MS no CEP. O capim hemártria apresentou valores de PB que variaram de 69,8g kg-1 de MS no verão à 99,7g kg-1 de MS no inverno. A quantidade de FDN variou de 702,9 até 811,6 g kg-1 de MS ao longo do ano; os valores mais baixos foram verificados no CEP. Os valores de lignina no CEC foram os maiores entre os capins (55,3 a 81,3g kg-1 de MS). A fração de carboidratos não estruturais variou de 20,9 a 85,5g kg-1 de MS. A quantidade de FDNcp variou de 673,6 até 794,5g kg-1 de MS. O capim hemártria teve os maiores valores da fração B2 e os menores valores da fração C de carboidratos durante todo o ano. Os valores da fração C de carboidratos variaram de 126,2 a 135,3g kg-1 de MS para o CEP, 149,2 a 177,7g kg-1 de MS para o CEC e 84,0 a 107,8g kg-1 de MS para o capim hemártria. As frações nitrogenadas A, B1, B2, B3 e C tiveram valores entre 9,8 e 36,4; 0,73 e 12,6; 11,1 e 44,1; 2,2 e 34,5 e 6,7 e 12,8g kg-1 de MS, respectivamente.

In vitro degradation of coast-cross (cynodon dactylon) by rumen microorganisms associated with Saccharomyces cerevisiae or humicola sp

Ruminal degradation of the dry matter and neural detergent figer of coast-cross (cynodon dactylon) forage, when previously inoculated with Saccharomyces cerevisiae or Humicolla sp., was estimated by in vitro incubation. The potential dry matter degradability was incresead in the presence of S. cerevisiae, whereas the incubation with Humicola sp. resulted in improvement of the neutral detergent fiber degradability. The rate of dry matter digestion was enhanced to above 15 per center with the inoculation with S. cerevisiae. The inoculation with S. cerevisiae or Humicola sp. increased the rate of digestion of the neutral detergent fiber in relation to the control treatment.