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Made available in DSpace on 2018-11-26T17:44:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) The aim of this study was to describe, for the first time, the embryogenesis and larval growth of the Paraitinga Brycon nattereri Gunther, 1864 reared in captivity. After artificial fertilization, eggs were incubated at constant temperature (similar to 19 degrees C) and collected every 15 min during the first 3 h and then every 3 h until hatching. Five larvae were collected daily over 15 days for evaluation of the length, yolk sac volume and specific growth rate. The following stages of embryonic development were identified: zygote, cleavage, gastrula, segmentation and larval. The hatching occurred after 50-54 h, with larvae poorly developed and fully depigmented, devoid of mouth and swimming capacity, presenting 6.32 mm total length and 3.64 mm(3) yolk sac volume. The mouth opening was observed between days 3-4 after hatching. The yolk sac absorption was slow during the first 3 days, increasing sharply after this period, being completed on the day 11. During this period there was a decrease in the larval growth rate. After yolk sac absorption, an increase in the growth rate was observed that coincided with the start of exogenous feeding. Cannibalism was not observed during the 15 days of evaluation. The initial development of B. nattereri was slow and poorly developed larvae in relation to other Brycon species, certainly due to the lower temperature required for egg incubation and larval rearing. Other studies are needed in order to develop techniques to improve the methods of incubating eggs and feeding larvae. Embrapa Tabuleiros Costeiros, Av Beira Mar 3250, BR-49025040 Aracaju, SE, Brazil Univ Estadual Paulista, Dept Biol & Zootecnia, Rua Moncao 226, BR-15385000 Ilha Solteira, SP, Brazil Univ Jose Rosario Vellano, Rod MG 179,Km 0,Campus Univ, BR-37130000 Alfenas, MG, Brazil Univ Fed Lavras, Dept Zootecn, POB 3037, BR-37200000 Lavras, MG, Brazil Univ Estadual Paulista, Dept Biol & Zootecnia, Rua Moncao 226, BR-15385000 Ilha Solteira, SP, Brazil FAPEMIG: CVZ-1609/06

SUMMARYThe crop rotation is a practice to protect and improve the soil properties and an alternative to improve the quality of crop residues is the application of fertilizers at the planting of cover crops. Thus, we evaluated the effect of fertilization with nitrogen, phosphorus and potassium (NPK) on organic matter production and chemical composition of cover crops succeeding the corn crop. The treatments consisted of the cultivation of Avena sativa L., Lupinus albus L., Pennisetum glaucum L., Raphanus sativus L. and Sorghum bicolor L. with (200 kg ha−1 of NPK [08-28-16] applied by broadcast seeding) and without fertilization at planting. Organic matter production by all cover crops, as well as concentrations of neutral detergent fibre (NDF) in shoots and roots of A. sativa L. and R. sativus L. were higher when they were fertilized. L. albus L. showed higher NDF and acid detergent fibre (ADF) contents than the other cover crops, with and without fertilization. Nitrogen concentration increased, but the carbon/nitrogen ratio (C/N) in the shoots of L. albus L., R. sativus L. and S. bicolor L. decreased when fertilization was applied. The use of N by the A. sativa L. and P. glaucum L. and of P and K by S. bicolor L. was 16, 54, 82 and 20% more efficient, respectively, when fertilization was applied. The A. sativa L., P. glaucum L. and R. sativus L. showed higher NDF/N, ADF/N and hemicellulose/N ratios in the fertilized treatment. Although the results obtained in this study are highly satisfactory, more research should be conducted to evaluate the decomposition of crop residues from cover crops fertilized with NPK, and the effects of this strategy on corn crops in succession.