Digestibilidade total e parcial e balanço nitrogenado em bovinos em pastejo no período das águas recebendo suplementos com nitrogênio não-proteico e/ou proteína verdadeira

Objetivou-se avaliar o efeito de diferentes relações entre proteína verdadeira e nitrogênio não-proteico sobre a digestibilidade, a síntese de proteína microbiana e o balanço de compostos nitrogenados em bovinos em pastejo durante o período das águas. Foram utilizados cinco novilhos mestiços Holandês × Zebu, castrados, com peso vivo inicial de 335±35 kg fistulados no rúmen e no abomaso. Os tratamentos foram: controle (somente pasto); e suplementos com ureia; com 2/3 de compostos nitrogenados oriundos da ureia e 1/3 de compostos nitrogenados oriundos da albumina; com 1/3 de compostos nitrogenados oriundos da ureia e 2/3 de compostos nitrogenados oriundos da albumina; e com albumina. Foram fornecidos 200 g/dia de proteína bruta (PB) a partir dos suplementos. O experimento foi conduzido segundo delineamento em quadrado latino 5 × 5, com cinco períodos experimentais, cada um de 15 dias. A suplementação não afetou os coeficientes de digestibilidade total nem o teor de nutrientes digestíveis totais da dieta; elevou as estimativas do coeficiente de digestibilidade aparente ruminal da PB, que migraram de negativa, no tratamento controle, para positivas, porém não diferentes de zero, nos tratamentos envolvendo suplementação. O fornecimento de suplementos elevou a concentração de nitrogênio amoniacal ruminal. O balanço de compostos nitrogenados aumentou com a suplementação. A substituição de ureia por albumina influenciou de forma cúbica o balanço de compostos nitrogenados, cuja estimativa foi maior para o suplemento com 1/3 de PB oriunda da ureia. A eficiência de síntese microbiana no rúmen não foi influenciada pelo fornecimento ou pela composição dos suplementos. A suplementação de bovinos em pastejo com fontes de compostos nitrogenados degradáveis durante o período das águas amplia a eficiência de uso do pasto, principalmente por ampliar a retenção de compostos nitrogenados no organismo.

Quality of the forage apparently consumed by beef calves in natural grassland under fertilization and oversown with cool season forage species

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo do balanço nitrogenado e da digestibilidade da matéria seca e proteína de rações, para ovinos, suplementadas com amiréia, uréia ou farelo de algodão

To evaluate the nutritional value of rations supplemented with different protein sources, an in vivo digestibility trial was conducted to determine the coefficients of digestibility for dry matter (DMDC) and crude protein (CPDC), nitrogen balance (NB) and the fecal non-protein nitrogen (NPN). Twenty - four 11-months - old lambs weighing 30.4 +/- 3.0 kg were blocked on the basis of their body weight and randomly allocated to three treatments groups; suplemented with cottonseed meal (CSM), starea (ST) or urea (UR). The DMDC was statistically superior for the Starea treatment (67.7%) over the others (64.3% and 64.1% for CSM and UR). The CSM, UR and ST rations had no influence on CPDC (63.9; 66.9 and 69.4%, respectively) and on fecal NPN (1,3; 1,2 e 1,3 g/day, respectively). The NB results were similar also among treatments (13,4; 9,0 e 10,5 g/day to CSM, UR and ST, respectively) although the ST treatment lambs excreted larger amounts of nitrogen in the urine (7.7 g/day) in relation to CSM (4.8g/day) and similar to UR treatment (6.5 g/day). Starea supplement in ruminant diets increased dry matter digestibility when compared to cottonseed meal and urea, but did not improve the efficiency of the nitrogen utilization by lambs.

Efeitos da amonização sobre a ocorrência de fungos, composição química e digestibilidade in vitro de fenos de grama Seda (Cynodon dactylon (L.) Pers.)

The experiment was conducted with grama seda (Cynodon dactylon (L.) Pers.) hays stored with a low moisture content (12-15%) and without chemical treatment, and hays stored with a high moisture content (20-25%) and treated with anhydrous ammonia (NH3) al 0.5 and 1.0% of DM, and urea at 0.9 and 1.8% of DM. At 65 days after treatment (AT) under a plastic cover, the bales were opened and samples were taken at 3, 15 and 30 days to determine the chemical composition and in vitro digestibility (IVDMD) of the hays. For the identification of fungi, samples were taken at 0, 15 and 30 days AT. The data were analyzed according to a split-plot design with the effects of the chemical treatments studied in the main plot and the effects of the periods of post-treatment studied in the sub-plots, Fourteen genera of fungi were observed in the hays, not treated and treated with NH3 and urea, with a higher occurrence of Cladosporium, Curvularia, Aspergillus, and Penicillium. Treatment with anhydrous ammonia and 1.8% urea controlled the occurrence of Aspergillus; however, Penicillium decreased in hays treated with ammonia 30 days AT. Ammoniation did not influence the contents of ADF, cellulose and lignin in the hays, but NDF and hemicellulose decreased with the use of ammonia 30 days AT. The CP contents and the IVDMD increased with ammoniation. The CP contents decreased in hays treated with NH3 as days AT increase, while hays treated with urea did not change.

Prediction of dry matter intake based on ruminal degradation from milking cows grazing coast-cross grass

Dry matter intake (DMI) of coast-cross grazing by crossbred Holstein-Zebu and Zebu lactating cows was calculated using in vitro dry matter digestibility from extrusa (four esophageal fistulated cows) and fecal output estimate with mordent chromium. Pasture was rotationally grazed with three days grazing period and 27 days testing period, adopting a stocking rate of 1.6 and 3.2 cows/ha, during the dry and rainy season respectively. Voluntary DMI was estimated from degradation characteristics using different equations. Predicted coast-cross DMI varied with models. The prediction of tropical forages dry matter intake from equations based in ruminal degradation parameters needs farther investigation before being employed in practice.

Efeito de diferentes relações volumoso: concentrado no consumo, digestibilidade aparente e partição da digestão da dieta de bovinos

Three steers equipped with ruminal and duodenal cannulas were fed roughage:concentrate ratios 80:20, 60:40 and 40:60 in order to study intake and apparent, rumen and post-rumen digestibilities. The roughage was ''coast cross'' (Cynodon dactylon) hay (5.67% CP and 83.30% NDF). Undigestible neutral detergent fiber (NDF) was used as dry matter (DM) flow marker. DM intake means were 77.99, 91.03 and 91.81g DM/kg BW0.75, for the 20, 40 and 60% concentrate diets, respectively. DM intake for the 20% diet was statistically (P < 0.05) different from the other two diets. Apparent digestion coefficient (%) of DM (50.48, 57.32 and 61.33), organic matter (OM) (52.03, 58.91 and 62.76) and gross energy (GE) (48.95, 56.40 and 60.00) increased significantly with the increase in concentrate ratio of the diets. For the following components the apparent digestion coefficients were not statistically different: NDF (44.54, 45.28 and 42.53), ADF (40.69 44.39 and 43.60), cellulose (51.54, 54.34 and 52.03), hemicellulose (49.63, 46.78 and 39.18) and starch (86.59, 91.89 and 93.21). DM, OM, NDF, ATF, cellulose and starch ruminal and post-ruminal digestibilities were not statistically different. But the ruminal digestibilities of hemicellulose (94.81, 90.26 and 85.99) and EG (93.85, 83.30 and 78.77) decreased significantly as the concentrate ratio of the diets increased. The post-ruminal digestibility of hemicellulose (5.19, 9.74 and 14.03%) and GE (6.12, 16.20 and 21.23%) increased as the concentrate ratio of the diets increased.

Variação na estrutura da vegetação de duas cultivares de Panicum maximum jacq. (colonião e tabiatã) submetidas a diferentes tipos de manejo. Composição em proteína bruta e digestibilidade In vitro da matéria seca

This work was carried out at FCAV-UNESP, Campus of Jaboticabal, Brazil, to study the effects of nitrogen fertilization (0 and 50 kg N/ha/cut), three sucessive periods of growth (December 21st 1987, January 25th 1988 and February 29th 1988)) and three cutting ages (28, 35 and 42 days) on composition in crude protein and in vitro dry matter digestibility of two cultivars of Panicum maximum Jacq. i.e., Coloniao and Tobiata. Plants were harvested in five vertical layers above soil level (0-20, 20-40, 40-60, 60-80 and over 80 cm). The samples were divided in: green leaves, green stems and dry material. Generally, values of in vitro dry matter digestibility and the levels of crude protein of both cultivars were greater in the higher layers of the vegetation, with a decrease, however, for the other layers and more advanced phases of plants development, mainly with no N fertilization.

Intestinal starch disappearance increased in steers abomasally infused with starch and protein

Steers (379 +/- 10 kg) with ruminal, duodenal, and ileal cannulas were used in a 5 x 5 Latin square digestion trial to quantify and evaluate the relationship between intestinal protein supply and intestinal starch disappearance. Treatments were infusions of 0, 50, 100, 150, or 200 g/d of casein along with 1,042 g/d of raw cornstarch. Abomasal infusions were accomplished by passing tubing and a pliable retaining washer through the reticular-omasal orifice into the abomasum. Steers were fed a 93% corn silage, 7% supplement diet that contained 12% crude protein at 1.65% body weight in 12 equal portions/d. Periods lasted 17 d (12 d for adaptation, 2 d of collections, and 3 d of rest). The quantity and percentage of organic matter and protein disappearance from the small intestine increased linearly (P < 0.03) with infused casein. Greater quantities of starch disappeared with increased casein infusion (P < 0.01). The infusion of 200 g/d of casein increased small intestinal starch disappearance by 226 g/d over the control. Casein infusion did not affect the quantity or percent of organic matter, starch, or protein disappearance in the large intestine. Treatments did not change ruminal ammonia N, ruminal pH, or plasma glucose concentrations. Starch disappearance from the small intestine was increased with greater protein flow to the duodenum of steers.

Do all tannins have similar nutritional effects? A comparison of three Brazilian fodder legumes

Three tropical legumes, namely Leucaena leucocephala, Sesbania sesban and Cajanus cajan, were subjected to chemical analysis plus in vitro, in situ and in vivo evaluations. Three different assays were used to determine total tannins: adsorption to polyvinyl pyrrolidine (PVPP-tannins), radial diffusion (RD-tannins) and protein precipitation capacity (BSA-tannins). Total phenols, total tannins and condensed tannins were highest for Sesbania. RD-tannins were correlated with total phenols (r(2) = 0.93), PVPP-tannins (r(2) = 0.92) and condensed tannins (r(2) = 0.99). The protein precipitation capacity of Sesbania, Leucaena and Cajanus were 25.9, 6.13 and 4.05 mu g BSA/g DM, respectively.Gas production at 24h was negatively correlated with total phenols (r(2) = 0.99), PVPP-tannins (r(2) = 0.99) and condensed tannins (r(2) = 0.91). The RD-, PVPP-tannins and the response to polyethylene glycol (PEG) in the gas production assay appeared to be useful as a first screen for tannins.In situ degradability did not reflect any adverse effects of tannins. However, in vivo experiments showed that the apparent DM digestibility of Sesbania and Leucaena was lower than the basal diet. The apparent protein digestibility was lower for all legumes compared to the basal diet. Most treatments caused a negative nitrogen balance. The problems associated with browse feeding were not only related to tannin contents, other factors such as inherently poor digestibility and low energy intake may also have lead to the poor animal performance on these diets. We propose, given the limitations of current tannin assays, that it is not possible to predict beneficial or harmful nutritional effects from total tannin concentrations per se. (C) 2004 Elsevier B.V. All rights reserved.

The use of extruded feed in fish food

In our country, the intensive culture of fish has been making progress due to the availability of extruded rations, which are characterized by the way they have been formulated to assist the nutritional demands of the tropical species and for facilitating a better practice of alimentary handling. This process checks the extruded product density and the desirable physical/chemical aspects to a diet that should be handled in the water, the critical factor of this activity. It is important to emphasize that this product stays to the surface of the water, facilitates the consumption control and the observation of the general aspects of the school of fish, as well as guaranteeing that no deterioration of the physical/chemical characteristics of the water occurs. The floating characteristic of the extruded ration is preferable for farmers because most of the tropical species feed at the surface of the water. In some cases, in the function of the alimentary habit, the thermal conditions of the water and the handling system produce granules with different densities. This is due to the humidity and the applied cooking heat, which modifies the time of hydration, and consequently the ability to float. To establish the physical presentation idea for a ration for tropical fishes, it is necessary that the pellets come in sizes, textures, humidities and densities in order to allow for the different phases of the lives of the fishes. This ration should be the result of characteristics of the species, such as the anatomophysiologics particularities, alimentary habits, digestive capacity and alimentary behavior. Only in this way is it possible to offer to those fishes a ration whose nutritious value and physical presentation facilitate the best biological and economic answers.Those aspects need to be reviewed because the tropical species that are cultivated in our country present selective behavior in relation to the size of the pellet. Generally, this has access to the digestive system without waste; the digestibility, therefore, is dependent upon the size of the particles and the physical aspects of the pellets. They should still consider that those granules could be less abrasive and softer. The extruded rations available in the national market present a qualitative reference to its proteic level, whose consequence allows us to infer that those are overestimated for the final phase of those fishes. Thus, the final cost of production is made unfeasible. In this point of view of the development of the national fish culture, and the growing adoption of the intensive system of production, it can link that such progress is a function of the availability of the rations in the extruded form. Although this technique of processing of rations has revolutionized the market in such a way that has been seen as preferable for farmers, some feel that there is a lack of products best suited for the initial phases of fingerlings production.

ENTEROTOXIN PRODUCTION IN STRAINS OF CAMPYLOBACTER-JEJUNI, ISOLATED FROM SWINE DIARRHEA

One hundred and twenty-six strains of Campylobacter jejuni isolated from swine with diarrhea were examined for the production of enteroxin, by culture filtrate inoculation into ileal loops in several animal species.Four (3,1 %) of the strains tested produced fluid in ligated ileal loop of albino rabbit, 19 (15 %) in rat and 14(11, 1 %) in swine. By the test of intragastric inoculation in suckling mouse, none of the strains revealed capacity to produce enterotoxin, although two strains were considered suspicious. Twelve (54,5 %) of the strains that induced ileal fluid in rat and swine produced cytotoxic effect in monkey kidney cells (Vero), affecting up to 60 % of the monolayer. However, no alteration was observed in hamster kidney cells (BHK).

THE EVOLUTIVE SIGNIFICANCE OF POLLEN USE AS PROTEIN RESOURCE BY TRIGONINI BEES (HYMENOPTERA, APIDAE, MELIPONINAE)

The origin of bees was marked by the change from the use of animal of vegetal protein to feed the larvae. The advantages of this change and the existence of some necrophagous species among the bees is discussed regarding to the poor digestibility of pollen.

In situ degradability of hand harvested or extrusa samples of Tanzania grass (Panicum maximum, Jacq.)

In order to compare the in situ degradability of tanzania grass samples obtained as by extrusa or hand plucked, three ruminal fistulated cows were used in a completely randomized block design with split-plot scheme. Five grams of extrusa or hand harvested grasses were placed in nylon bags rumen incubated during 3, 6, 12, 24, 48, 96 and 120 hours. The degradability of DM, CP, NDF and ADF were, in this sequence, 62.59, 80.88, 50.73 and 46.65%, for hand-harvested grass; and 79.53, 90.97, 71.21 and 65.68%, for extrusa. In situ degradability data of hand harvested samples were not reliable.

Digestilidade in vitro do bagaço de cana-de-açúcar hidrolisado, submetido a diferentes tempos de estocagem e de adaptação ao bovino doador de fluido ruminal

An experiment was conducted to study the in vitro digestibility of dry matter (IVDMD) and gross energy (IVGED) of hydrolyzed sugarcane bagasse with different storage times and two periods of adaptation of the bovine to the diet. A completely randomized design with four treatments and five replications was used. Treatments A,B,C, and D which corresponded to the times of 0, 15, 30, and 45 days of storage time period of the bagasse, respectively. Each treatment was studied at 7 and 45 after adaptation of the bovine ruminal donor to the diet. After 30 days storage, the bagasse IVDMD was inpaired for both 7 and 45 days of adaptation. Averages values of 25.8; 25.9; 23.1 and 23.3% were obtained for IVDMD with seven days of adaptation, and 25.04; 21.6; 12.5 and 11.4% with 45 days of adaptation for storage periods of 0; 15; 30 and 45 days, respectively. For IVGED, the averages obtained were 33.4; 27.8; 30.9; and 27.2% with seven days, and 30; 26.6; 20.6 and 14.5% with 45 days of adaptation for storage periods of 0, 15, 30 and 45 days, respectively.

Valor nutritivo do feno de Brachiaria decumbens Stapf cv. Basilisk submetido a tratamento com amônia anidra ou uréia

The effects of the ammoniation of Brachiaria decumbens hay was evaluated. The hay bales were distributed into a complete randomized block design, with four replications and they were submitted to the treatments: untreated or treated with anhydrous ammonia (NH3)(2,0 and 3,0% of the DM) or with urea (3,6 and 5,4% of the DM). All the hays bales remained under plastic cover for 45 days. After three days of aeration, samples were collected for the determination of the chemical composition, nitrogenous compounds fraction and the in vitro dry matter (IVDDM) and organic matter (IVDOM) digestibility. In the metabolic study, Saanen goats breed was used in a 5x5 Latin squares design, where the apparent digestibility, the voluntary intake and the nutritive value index were evaluated. The ammoniation increased the contents of the total N, N ammonia (N-NH3) and non-protein N, with high effect on the levels of 3,0% of NH3 and 5,4% of urea. There were no differences between the level of 3,0% of NH3 and 5,4% of urea for the total N, N-NH3 and NPN. However, the treatment with 3,0% of NH3 allowed a larger fixation of N in ADIN and NDIN forms. The ammoniation increased the IVDMD and IVDMO and reduced the contents of neutral detergent fiber (NDF), hemicellulose, acid detergent fiber (ADF) and lignin, but it did not alter the cellulose and gross energy contents. The ammoniation increased the DM, OM, CP, NDF, ADF, hemicellulose, cellulose and gross energy apparent digestibility and as well as the voluntary intake of DM, digestible DM, digestible OM, digestible protein, digestible energy and the nutritive value index. The ammoniation increased the hay nutritive value index, but there were no differences between the levels of NH3 and urea.