Ammonia levels on in vitro degradation of fibrous carbohydrates from buffel grass

This study was carried out to examine the degradation dynamics of neutral detergent fibre (NDF) and the profile of volatile fatty acids that originate from the fermentation of buffel grass (Cenchrus ciliaris, L.) with various levels of ammonia in the growth medium. The treatments consisted of six levels of ammonia in the growth medium (0, 5, 10, 15, 20 and 30 mg/dL), which were obtained by adding urea. These in vitro incubation times were evaluated in three replicates per time for 0, 3, 6, 9, 12, 24, 36, 48, 72 and 96 hours. Rumen concentrations of acetate and propionate responded quadratically to the ammonia levels. The treatment with 15 mg/dL of ammonia nitrogen in the rumen fluid provided mean acetate and propionate contents of 57.6 mM and 23.1 mM, respectively. Urea addition elevated the degradation rate of potentially degradable fraction of NDF (pdNDF) from 2.5% to 20.1% in comparison with the treatment without urea and to a reduction in estimated discrete lag time from 0.34 to 2.31 hours. Urea supplementation increased the specific microorganism growth rate from 2.6% to 20.1%. At the end of the incubation trial, NDF degradation showed a quadratic response, with maximum value obtained at 17.76 mg/dL of ammonia in the rumen fluid. Urea improves the degradation dynamics of NDF from deferred buffel grass and increases the concentrations of acetate and propionate.Keywords: Cenchrus ciliaris, degradation kinetics, non-protein nitrogen, ure

Effect of salt concentrations on in vitro rumen fermentation of cellulose, starch, and protein

The aim of this study was to evaluate the effects of various concentrations of three salts (sodium chloride (NaCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2)) on the in vitro rumen fermentation of cellulose, starch, and protein substrates. Six salt concentrations were tested, separately, namely 0, 100, 200, 400, 800, and 1600 mg/dL. The experiment was conducted using the completely randomized design in a 6 × 3 × 3 factorial arrangement with main effects of salt concentration and salt type (six levels of three salts (NaCl, MgCl2, or CaCl2) (0, 100, 200, 400, 800, and 1600 mg/dL) into three substrates [starch, cellulose, and glucose]) with three replicates. Cellulose- and glucose-fermenting bacteria were sensitive to NaCl concentrations greater than 400 mg/dL (17.48 decisiemens per metre (dS/m)) and 800 mg/dL (20.55 dS/m) in the media, respectively. In contrast, starch-fermenting bacteria continued to grow in NaCl concentrations up to 1600 mg/dL (29.09 dS/m). Thus, it was concluded that starch-fermenting microorganisms tolerated higher concentrations of NaCl compared with the other microbial groups. Cellulose-fermenting microorganisms are less tolerant to MgCl2 in relation to the other microbial groups. Starch, cellulose-, and glucose-fermenting bacteria from cattle tolerate CaCl2 concentrations of up to 1600 mg/dL (12.26 dS/m). These results suggest that brackish water may be used for ruminants. However, it is important perform an analysis of that water and then to adjust diets to minimize the effects of types of salt and concentrations of salt on rumen microorganisms. Keywords: brackish water, dissolved salts, rumen microbes, water qualit

Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients

The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23®, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody > or = 1.3 µg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90% of subjects for serotypes 3 and 9V, and in 65% for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children

Fontes, doses e modo de aplicação de nitrogênio em feijoeiro no sistema plantio direto Effect of sources, doses and nitrogen split in winter common bean in no tillage system

O manejo do N correspondente à maior produtividade de grãos, do ponto de vista econômico, muitas vezes não é o mais rentável e, portanto, não será adequado para recomendação ao produtor. O objetivo do trabalho foi o de estudar o efeito de fontes, doses e parcelamento do nitrogênio no desenvolvimento e na produtividade de grãos do feijoeiro de inverno no sistema plantio direto, correlacionado com análise econômica simples, em Latossolo Vermelho Distrófico argiloso, em Selvíria (MS), em 2005. O delineamento experimental foi o de blocos casualizados em esquema fatorial 3 x 5 x 2, com trinta tratamentos e quatro repetições, constituídos por três fontes de nitrogênio (uréia, sulfato de amônio - SA e mistura - ½ N uréia + ½ N SA), cinco doses de N (0, 50, 100, 150 e 200 kg ha-1), aplicadas na semeadura ou parceladamente. Com o N proveniente do sulfato de amônio proporcionou-se mais produtividade de grãos e, com a uréia, maior eficiência econômica. A produtividade foi incrementada com o aumento da adubação nitrogenada até a dose de 198 kg ha-1, proporcionando-se, em média, aumento de 44% na produtividade comparada à da testemunha sem N. O parcelamento da adubação nitrogenada não foi economicamente viável.<br>Several works show the efficiency of the nitrogen fertilization in the yield increase common bean yield; however, there is need of new studies, because of the economical point of view, the management of nitrogen that corresponds the largest yield of grains many times it does not correspond to the most profitable and, therefore, it does not fit for recommendation to the producer. The objective of the work was to study the effect of sources, doses and nitrogen split in the development and yield of winter common bean in no tillage system, correlated with a simple economical analysis. The trial was conducted in Selvíria county, Mato Grosso do Sul, State, in 2005, in a dystrophic clayey Latosol - Haplustox. A randomized blocks design was used, in a factorial scheme 3x5x2 with 30 treatments and 4 repetitions constituted by three sources of nitrogen (ammonium sulphate, urea and ammonium sulphate ½ of N + urea ½ of N), with different doses of nitrogen (0, 50, 100, 150 e 200 kg ha-1) applied at sowing or split (1/3 at sowing + 2/3 V4-4 growth stage). The source of nitrogen from ammonium sulphate provides larger yield of grains of the winter common bean; however, the urea is that provides larger economical efficiency. The increase of the nitrogen fertilization increases the yield up to 198 kg/ha of N, providing on average an increase of 44% in the yield compared with the control (without N). The nitrogen split was not economically viable