Digestibilidade aparente de ingredientes do Semi-Árido Nordestino para tilápia do Nilo Apparent digestibility of ingredients of the Northeast Semi-Arid for Nile tilapia

O experimento avaliou o coeficiente de digestibilidade aparente (CDA) da matéria seca (MS), energia bruta (EB), extrato etéreo (EE) e proteína bruta (PB) de ingredientes do Semi-Árido Nordestino: farinhas do feno de maniçoba (FM), do feno de leucena (FL) e do feno da folha de mandioca (FFM), raspa de mandioca (RM) e resíduos de vitivinícola (RV) para tilápia do Nilo (Oreochromis niloticus). Os CDA para a MS, EB, EE e PB foram de 20,74%, 30,30%, 48,36% e 71,72% para FL; 19,34%, 17,08%, 30,03% e 44,88% para FM; 30,32%, 23,04%, 4,43% e 21,07% para FFM; 72,85%, 70,62%, 81,78% e 84,51% para RM e de 33,38%, 50,80%, 79,39% e 67,25% para RV. O feno de leucena, a raspa de mandioca e os resíduos de vitivinícola são promissores para a formulação de rações. A utilização dos ingredientes testados na composição de rações artesanais ou comercias para a tilápia do Nilo, bem como os níveis seguros para a inclusão destes devem ser testados.The experiment evaluated the apparent digestibility coefficient (CDA) of dry matter (DM), gross energy (GE), ether extract (EE) and crude protein (CP) of regional alternative ingredients of Semi-arid Northeast as flour of maniçoba hay (FM), of Leucaena hay (FL) and of cassava leaves (FFM), as well as cassava scrapings (RM) and residues of wine (RV) for Nile tilapia (Oreochromis niloticus). CDA for DM, GE, EE and CP were 20.74%, 30.30%, 48.36% and 71.72% for FL, 19.34%, 17.08%, 30.03% and 44.88% for FM, 30.32%, 23.04%, 4.43% and 21.07% for FFM, 72.85%, 70.62%, 81.78% and 84.51% for RM and 33.38%, 50.80%, 79.39% and 67.25% for RV. The leucaena hay, the cassava scrapings and residues of wine are promising for the formulation of diets for Nile tilapia. However, the use of tested ingredients in commercial and homemade diets to Nile tilapia, as well as the safe inclusion levels of these should be tested

Economic viability of production of Nellore heifers on Urochloa brizantha cv. Marandu pastures deferred and fertilized with nitrogen

The objective of this study was to evaluate the effect of different levels of nitrogen on deferred pastures of Urochloa brizantha cv. Marandu, and the implications on the economic viability of production of Nellore heifers. This was a completely randomized design with four treatments (T1 = deferred pasture without nitrogen fertilization; T2 = deferred pasture fertilized with 50 kg N ha-1, T3 = deferred pasture with 100 kg N ha-1, T4 = deferred pasture with 150 kg N ha-1) and four replications (16 fertilized paddocks). First, there were used 48 Nellore heifers, average eight months of age and initial body weight of 178.69 ± 26.67 kg, with three heifers in each paddock, in all treatments, in a continuous grazing system, with variable stocking rate. Only the treatment the without nitrogen fertilization showed negative monetary values of R$-181.96, R$ ha-1 -72.79 and R$@-1 -32.11. The treatment with 50 kg N ha-1 achieved the highest positive monetary values of R$ 756.02, R$ha-1 302.40 and R$ @-1 50.52. Economic viability data in beef heifer production demonstrate that the treatment with 50 kg N ha-1 is the most financially viable under the conditions of this study.

Ingestive behavior and nitrogenous compounds balance of heifers on pastures of Urochloa brizantha cv. Marandu deferred and fertilized with nitrogen

Objetivou-se com este estudo avaliar o efeito de diferentes doses de nitrogênio em pastos de Urochloa brizantha cv. Marandu diferidos, e suas implicações sobre o comportamento ingestivo e o balanço de compostos nitrogenados de novilhas Nelore. Utilizou-se o delineamento inteiramente ao acaso, com quatro tratamentos (doses de nitrogênio) e quatro repetições (número de piquetes adubados). Foram utilizadas 16 novilhas da raça Nelore, com média de oito meses de idade e com peso corporal inicial de 178,69 ± 26,67 kg, sendo quatro novilhas por tratamentos. Os resultados foram avaliados por meio de análise de variância e regressão a 5% de probabilidade. As atividades comportamentais dos animais não se alteraram (P > 0,05) com o uso das diferentes doses de nitrogênio nos pastos com tempos médios de 576,25 minutos (10h:00min) em pastejo, 509,84 minutos (8h:50min) em ruminação, 315,16 minutos (5h:25min) em ócio e 39 minutos alimentando no cocho. Para o nitrogênio ingerido, nitrogênio digerido e o nitrogênio retido (g/dia) e o nitrogênio digerido (% do N ingerido), houve efeito linear crescente (P 0,05) das doses de nitrogênio, com média de 15,79 mg/dL. As atividades comportamentais das novilhas não são afetadas pelas doses de nitrogênio em pastos de Urochloa brizantha cv. Marandu diferidos. O nitrogênio ingerido, nitrogênio retido (g/dia), o nitrogênio digerido (g/dia) e (% do N ingerido), a concentração de nitrogênio ureico na urina, e as excreções de ureia e de nitrogênio ureico na urina são influenciados pela quantidade crescente de proteína bruta na forragem oriundas da adução nitrogenada, nas condições de realização desta pesquisa.This study has to evaluate the effect of different levels of nitrogen in pastures Urochloa brizantha cv. Marandu deferred, and its implications on feeding behavior and the nitrogen balance of Nelore heifers. The design was used completely randomized, with four treatments (nitrogen of levels) and four replications (number of fertilized paddocks). Were used 16 heifers Nellore, averaging eight months of age and initial body weight of 178.69 ± 26.67 kg, 4 heifers for treatments. The results were evaluated by analysis of variance and regression at 5% probability. The nitrogen levels did not influence the behavioral activities with average time of 576.25 minutes (10:00) grazing, 509.84 minutes (8h50min) in rumination, 315.16 minutes (5h25min) in idle and 39 minutes in the feeding trough. For nitrogen intake, digested nitrogen and the nitrogen retention (g/day) and the digested nitrogen (%N ingested), there was increasing linear effect (P 0.05) nitrogen in the feces and urine nitrogen (g/day), and not the nitrogen retention (% of N ingested) and nitrogen retention (% of digested N), whose mean values were 22.98 g/day; 39.48 g/day; 46.83% and 78.10%, respectively. For N urea in urine, there was increasing linear effect (P0.05) of nitrogen rates, averaging 15.79 ml/dL. The behavioral activities of the heifers are not affected by nitrogen levels in pastures Urochloa brizantha cv. Marandu deferred. The ingested nitrogen, retained nitrogen (g/day), digested nitrogen (g/day) (% of ingested N), the urea nitrogen in urine, excretion in urine urea and urea nitrogen in urine are influenced by the amount increasing crude protein forage derived nitrogen adduction, these results are important to prevent the economic losses due to excessive supply of protein in the diet.

Fermentation characteristics and nutritional value of elephant grass ensiled with old man saltbush

The effects of the addition of saltbush on the fermentation characteristics and nutritional value of silages of elephant grass (Pennistum purpureum Schum.) were studied through a completely randomized design with six old man saltbush (Atriplex nummularia Lind) levels (0, 20, 40, 60, 80 and 100 %) in substitution of the grass natural matter, with six replicates. Elephant grass presented 18.9% dry matter (DM) and silages were produced in experimental PVC silos, which were open at 70 days after ensilage. The increasing old man saltbush levels had increasing linear effect on the DM content of silages. There was quadratic effect for the contents of lactic and acetic acids and in vitro DM digestibility. Contents of butyric acid were negligible. Values pH of and N-NH3 contents had increasing linear effect. Linear effect of the increasing levels of old man saltbush was verified on the CP contents. Neutral detergent fiber, total carbohydrates and ether extract were not affected, whilst acid detergent fiber content showed decreasing linear effect. The addition of old man saltbush in the ensilage of elephant grass favored the fermentation process, promoting good lactic acid contents and reducing acetic acid, pH, dry matter loss and ammoniacal nitrogen, in addition to improving the nutritional quality of the elephant grass silages