Feeding strategy with alternate fasting and refeeding: effects on farmed pacu production

P>A 36-day trial was conducted to determine the effects of repetitive periods of food restriction and refeeding on growth and energy metabolism in pacu (Piaractus mesopotamicus). A total 264 juvenile fish (36.9 +/- 2.8 g) were fed with the experimental diet for 36 days using three regimes: (i) feeding daily to satiation (FD); (ii) no feed for 3 days, then feeding the same amount offered to the control groups for the next 3 days (NF/R controlled); and (iii) no feed for 3 days, then feeding to apparent satiation for the next 3 days (NF/R at satiation). The treatments were distributed into four tanks each. WG and SGR were higher in FD group. Fish refed showed hyperphagia just up to the second day of refeeding. The worst feed conversion rate and the lowest protein efficiency ratio were found in fish NF/R controlled. The lowest values of visceral fat somatic index were found in both fasted fish groups, particularly in NF/R at satiation. The LL and glycogen concentrations, and the hepatosomatic index were all elevated in both feed restricted fish. Muscle lipid showed a tendency to decrease after the cycle of fasting and refeeding. Plasma free fatty acids and glucose levels were elevated in fish subjected to feeding restrictions while serum triglycerides levels were reduced. Triiodothyronine levels were significantly depressed in fish from the NF/R-controlled group and remained at the same levels as the control fish in fish NF/R at satiation. Results indicated that fish subjected to cyclic periods of 3-day satiation or controlled feeding after 3-days of fasting were unable to achieve the final body weight of fish fed to satiation after 36 days.

Pseudomonas aeruginosa LBI production as an integrated process using the wastes from sunflower-oil refining as a substrate

Pseudomonas aeruginosa LBI produced surface active rhamnolipids when cultivated on waste from the sunflower-oil process under different conditions. These biosurfactants, which reduce the superficial and interfacial tensions between fluids, offer advantages over their chemical counterparts, especially because of their ecological acceptability. These molecules can be used in fields as diverse as chemical, pharmaceutical and petrochemical industries. In this work, we present the effect of C/N ratio on growth and production yield. The best production yields (Y-P/S) were achieved for C/N ratios (in g/g) of 8/1 (0.22) and 6.4/1 (0.23). The product concentration was very satisfactory (7.3 g/L) at C/N ratio of 8/1, especially when considering that the substrate was basically composed of wastes that would otherwise constitute an environmental disposal problem. (c) 2007 Elsevier Ltd. All rights reserved.

Economic viability of the piaucu Leporinus macrocephalus (Garavello & Britski, 1988) production

Brazilian fish farms presented an accelerated development during the early 90's, mainly because of the increase in fee-fishing operations. To meet the demand of this market, fish production and supply became excessive and, as a consequence, the number of fee-fishing operations, farmers and the final selling price, decreased. This study analyzes the technical aspects, production cost, profitability and economic viability of the production of piaucu (L. macrocephalus) in ponds, based on information from a rural property. Feeding and fingerling costs amount to approximately 47.1 % of the total production cost, representing together with the final selling price the most important factor affecting profitability. The payback period was 8.3 years, the liquid present value US$ 291.07, the internal return margin 9%, and the income-outcome ratio was 1.01, which represents an unattractive investment as a projection based on current conditions. The improvement in productive efficiency enhances the economic valuation index, and that the relative magnitude of cost and income are the most important points for the economic viability of the studied farm.

Quality of Cotesia flavipes (Hymenoptera: Braconidae) reared at different host densities and the estimated cost of its commercial production

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Limestone and oyster shell for brown layers in their second egg production cycle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Prediction equations to estimate the demand of energy and crude protein for maintenance, gain and egg production for laying Japanese quails

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biomass production and accumulation of nutrients in shoots of Giant Guinea sorghum plants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Xylan from corn cobs, a promising polymer for drug delivery: Production and characterization

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Production of a low young modulus titanium alloy by powder metallurgy

Titanium alloys have several advantages over ferrous and non-ferrous metallic materials, such as high strengthto-weight ratio and excellent corrosion resistance. A blended elemental titanium powder metallurgy process has been developed to offer low cost commercial products. The process employs hydride-dehydride (HDH) powders as raw material. In this work, results of the Ti-35Nb alloy sintering are presented. This alloy due to its lower modulus of elasticity and high biocompatibility is a promising candidate for aerospace and medical use. Samples were produced by mixing of initial metallic powders followed by uniaxial and cold isostatic pressing with subsequent densification by isochronal sintering between 900 up to 1600 °C, in vacuum. Sintering behavior was studied by means of microscopy and density. Sintered samples were characterized for phase composition, microstructure and microhardness by X-ray diffraction, scanning electron microscopy and Vickers indentation, respectively. Samples sintered at high temperatures display a fine plate-like alpha structure and intergranular beta. A few remaining pores are still found and density above 90% for specimens sintered in temperatures over 1500 °C is reached.

Use of high moisture corn silage replacing dry corn on intake, apparent digestibility, production and composition of milk of dairy goats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Calcium and available phosphorus levels for laying hens in second production cycle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of the calcium level and limestone particle size on the performance of semi-heavy layers in the second cycle of egg production

An experiment was carried out at the Research and Development Unit of Brotas aiming at evaluating dietary calcium level and limestone particle size on the production performance of commercial (Hy-Line Brown) layers in the second lay cycle. Experiment duration was 112 days. A total number of 288 hens, with 83 weeks of age in the beginning of the experiment, were used in a completely randomized experimental design in a factorial arrangement of 2x3, with two calcium levels (3.5 and 4.0%) and three limestone particle size compositions: 100% fine limestone (FL), 30% coarse limestone (CL) + 70% fine limestone (FL), and 50% (CL) + 50% (FL), with six replicates of eight birds each. Egg weight (g), egg production (%), egg mass (%), feed intake (g), feed conversion ratio (kg/dz and kg/kg), mortality (%), and egg loss (%) were evaluated. The analysis of variance did not detect significant differences (p>0.05) among treatments on any of the evaluated performance parameters. It was concluded that the tested calcium levels and limestone particle composition did not influence the performance of semi-heavy layers in second production cycle.

Testicular thermoregulation in Bos indicus, crossbred and Bos taurus bulls: relationship with scrotal, testicular vascular cone and testicular morphology, and effects on semen quality and sperm production

Mechanisms of testicular thermoregulation, the relationship of scrotal, testicular vascular cone (TVC), and testicular morphology with thermoregulatory capability, and their effects on semen quality and sperm production were studied in 20 Bos indicus, 28 crossbred, and 26 Bos taurus bulls. The ratio of testicular artery length and volume to testicular volume were larger (P < 0.05) in B. indicus and crossbred bulls than in B. taurus bulls (1.03 and 0.94 cm/cm(2). versus 0.48 cm/cm(3); 0.034 and 0.047 ml/cm(3) versus 0.017 ml/cm(3), respectively). Testicular artery wall thickness (average 192.5, 229.0, and 290.0 mum, respectively) and arterial-venous blood distance in the TVC (average 330.5, 373.7, and 609.4 pm, respectively) were smallest in B. indicus, intermediary in crossbred, and greatest in B. taurus bulls (P < 0.05); the proximity between arterial and venous blood was consistent with the estimated decrease in arterial blood temperature after passage through the TVC (5.9, 5.0, and 2.9 degreesC, in B. indicus, crossbred, and B. taurus bulls, respectively). In crossbred and B. taurus bulls, there was a positive top-to-bottom scrotal temperature gradient and a negative testicular subtunic temperature gradient. However, in B. indicus bulls, both scrotal and testicular subtunic temperatures gradients were positive. Differences in the vascular arrangement, characteristics of the artery (e.g. wall thickness) or thickness of the tunica albuginea may have affected the testicular arterial blood and subtunic temperatures in B. indicus bulls. Better testicular thermoregulatory capability was associated with increased scrotal shape (pendulosity), testicular artery length and volume, and top-to-bottom gradient of the distance between the artery wall and the veins in the TVC. Increased semen quality was associated with increased testicular volume and scrotal subcutaneous (SQT) temperature gradient, and with decreased scrotal surface and testicular temperatures. Increased sperm production was associated with increased testicular artery volume, testicular volume, and SQT temperature gradient, and with decreased testicular artery wall thickness, scrotal circumference (SC), and scrotal surface, testicular subtunic, and epididymal temperatures. In conclusion, morphology of the TVC may contribute to the greater resistance of B. indicus bulls to high ambient temperatures by conferring a better testicular blood supply and by facilitating heat transfer between the testicular artery and veins. Testicular thermoregulation was associated with opposing scrotal and testicular subtunic temperatures gradients only in crossbred and B. taurus bulls. Scrotal, TVC, and testicular morphology influence testicular thermoregulatory capability and were associated with differences in semen quality and sperm production. (C) 2003 Elsevier B.V. All rights reserved.

The effects of propolis on antibody production by laying hens

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Phenology, sex ratio, and spatial distribution among dioecious species of Trichilia (Meliaceae)

The flowering, sex ratio, and spatial distribution of four dioecious species of Trichilia (Meliaceae) were studied in a semi-deciduous forest in southeastern Brazil. All reproductive trees (T. clausseni, T. pallida and T. catigua) with dbh greater than or equal to5 cm within a 1-ha plot were collected, sexed, mapped and, for individuals of each species, the distances to the nearest neighbour of the same and opposite sex were measured. For the shrub species T elegans (dbh <5 cm), all reproductive individuals were sampled randomly in 10 samples of 10 x 10 m. The reproductive phenology was observed at weekly to monthly intervals from May 1988 to January 1990. The species are strictly dioecious, did not present any sex-mixed trees or sex switching during the study, and sex ratio did not differ significantly from 1:1. The size distributions and the relative size variation were not significantly different. between sexes. There was no significant segregation or clumping between individuals of either sex and no fruit production without pollination. Onset of flowering and flowering peak were synchronous between male and female plants for all species studied. Flower synchrony was related to outcrossing and pollinator attraction rather than climatic factors.