The objective of the present study was to evaluate environmental impacts caused by a system of shrimp farming in net-pen on water quality and on the structure of zooplanktonic community. The study was carried out in Baía de Guaratuba, were the cultivations were conducted in 300 net-pens (3.6 m in length, 3.6 m in width, and 2 m in depth), distributed in an area of approximately 4,200 m2 in 720 shrimp/m2 density. Concentrations of ammonia, nitrite and phosphate in the […]

The aim of this study was to evaluate management, erythrocyte features and blood glucose level of pacu (Piaractus mesopotamicus), stocked at different densities in cages. It was used 2,700 fish with initial average weight of142.11 ± 10.54 g distributed in nine cages of 5 m3 of useful volume during 240 days. A complete random design was used, with three densities (200, 300 and 400 fish per cage), each one with three replicates. Only final weight and weight gain decreased with […]

The present study aimed to evaluate the possibility of reducing the dietary protein content for post-larvae of Pacific white shrimp (Litopenaeus vannamei) through diet supplementation with taurine amino acid. Six practical isoenergetic (15.48 kJ ME/g) diets were formulated to contain two protein concentrations (35% and 45% crude protein, CP) and 3 levels of taurine supplementation (0, 5 and 10 g/kg) in a 2 × 3 factorial scheme, with four replicates. One hundred post-larvae (initial weight 0.14 ± 0.01 g) were […]

The aim of this study was to evaluate the performance of pacu (Piaractus mesopotamicus) raised in cages and fed diets containing levels of crude protein (CP) and digestible energy (DE). It was used 3.960 fish with an average initial weight of 293.38 ± 5.67 g, distributed in 18 net-ponds with 5 m3, with 220 fish per experimental unit (44 fish/m3) in a 3 × 2 factorial scheme composed of three levels of crude protein (25, 30 and 35%) and two […]

The experiment was conducted to determine fractioning of carbohydrate and protein of elephantgrass silage containing cassava meal, coffee hulls and cocoa meal. A completely randomized experimental design was used in a 3 × 4 factorial scheme, composed of three byproducts added to elephantgrass at four levels (0, 10, 20 and 30% of natural matter), each one with five repetitions. The material was ensiled in PVC silos, which remained closed for 60 days. Cassava meal contributed to reduce the content of […]

The objective of the present study was to evaluate the aerobic stability and losses during the fermentation process of triticale silages in single crop or in mixtures with oats and/or legumes. The following crops were used for silage production: triticale (X. Triticosecale Wittimack), triticale intercropped with forage pea (Pisum arvense) and triticale intercropped with oats (Avena strigosa Schreb), forage pea and vetch (Vicia sativa). The dry matter content and its recovery did not differ among the silages. Buffer capacity was […]

Morphogenical and structural characteristics of black oats (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.) on pastures managed under two grazing intensities were quantified by using marked tiller technique. The expected intensities of disappearance of forage mass initial value were 35% (low) and 65% (high). Experimental animals were sheep and interval among grazing was determined through 300 degree-day thermal sum. The experimental design was completely randomized with two grazing intensities and two replicates. Leaf blades of oats and ryegrass […]

The experiment was carried out to select genotypes of Lotus corniculatus L. (Draco, São Gabriel and UFRGS) more tolerant to aluminum, using the technique of selection in nutrient solution. The solution contained 200 µmol/L calcium (CaCl2) and 100 µmol/L aluminum (AlCl3) and a pH controlled in the range from 4.1 to 4.3. It was performed two cycles of selection, in which the seedlings were selected by the root final length. Subsequently, the genetic gain achieved in the cycles of selection […]

Possible effects of brightness restriction, obtained by different Pinnus taeda tree densities, on the production and quality of black oat (Avena strigosa Schreb) cv. Common, white oat (Avena sativa L.) cv. FAPA 2, annual ryegrass (Lolium multiflorum L.) cv. Common, hairy vetch (Vicia villosa), wheat (Triticum aestivum L.) cv. dual purpose BRS Tarumã were studied. It was evaluated three brightness levels: 1 – full sunlight with no trees; 2 – 30% of radiation restriction, using 15 × 3 m spacing […]

It was tested the effects, in a medium term, of four methods to control undesirable plants on forage production and dynamic of vegetation in a representative area of natural pasture in the transition between Serra do Sudeste and the Depressão Central in Rio Grande do Sul. The control methods were the following: without control, mechanical control with spring mowing, mechanical control with autumn mowing and chemical control with Tordon commercial herbicide based on Picloram + 2,4-D at the dosage 5 […]