Growth performance and body composition of pacu Piaractus mesopotamicus (Holmberg 1887) in response to dietary protein and energy levels

Improper dietary protein and energy levels and their ratio will lead to increased fish production cost. This work evaluated effects of dietary protein : energy ratio on growth and body composition of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5 +/- 0.4 g) were fed twice a day for 10 weeks until apparent satiation with diets containing 220, 260, 300, 340 or 380 g kg-1 crude protein (CP) and 10.9, 11.7, 12.6, 13.4 or 14.2 MJ kg-1 digestible energy (DE) in a totally randomized experimental design, 5 x 5 factorial scheme (n = 3). Weight gain, specific growth rate increased and feed conversion ratio (FCR) decreased significantly (P < 0.05) when CP increased from 220 to 271, 268 and 281 g kg-1 respectively. Pacu was able to adjust feed consumption in a wide range of dietary DE concentration. Fish fed 260 CP diets showed best (P < 0.05) protein efficiency ratio and FCR with 11.7-12.6 MJ kg-1; but for the 380 CP-diets group, significant differences were observed only at 14.2 MJ kg-1 dietary energy level, suggesting that pacu favours protein as energy source. DE was the chief influence on whole body chemical composition. Minimum dietary protein requirement of pacu is 270 g kg-1, with an optimum CP : DE of 22.2 g MJ-1.

Identification of in vitro phosphorylation sites in the growth cone protein SCG10. Effect Of phosphorylation site mutants on microtubule-destabilizing activity.

SCG10 is a neuron-specific, membrane-associated protein that is highly concentrated in growth cones of developing neurons. Previous studies have suggested that it is a regulator of microtubule dynamics and that it may influence microtubule polymerization in growth cones. Here, we demonstrate that in vivo, SCG10 exists in both phosphorylated and unphosphorylated forms. By two-dimensional gel electrophoresis, two phosphoisoforms were detected in neonatal rat brain. Using in vitro phosphorylated recombinant protein, four phosphorylation sites were identified in the SCG10 sequence. Ser-50 and Ser-97 were the target sites for protein kinase A, Ser-62 and Ser-73 for mitogen-activated protein kinase and Ser-73 for cyclin-dependent kinase. We also show that overexpression of SCG10 induces a disruption of the microtubule network in COS-7 cells. By expressing different phosphorylation site mutants, we have dissected the roles of the individual phosphorylation sites in regulating its microtubule-destabilizing activity. We show that nonphosphorylatable mutants have increased activity, whereas mutants in which phosphorylation is mimicked by serine-to-aspartate substitutions have decreased activity. These data suggest that the microtubule-destabilizing activity of SCG10 is regulated by phosphorylation, and that SCG10 may link signal transduction of growth or guidance cues involving serine/threonine protein kinases to alterations of microtubule dynamics in the growth cone.

Skeletal muscle protein content of lipolytic inhibitor G(0)/G(1) switch gene-2 protein: the effect of endurance training

The first and rate-limiting step of lipolysis is the removal of the first fatty acid from a triglyceride molecule; it is catalyzed by adipose triglyceride lipase (ATGL). ATGL is co-activated by comparative gene identification-58 (CGI-58) and inhibited by the G(0)/G(1) switch gene-2 protein (G0S2). G0S2 has also recently been identified as a positive regulator of oxidative phosphorylation within the mitochondria. Previous research has demonstrated in cell culture, a dose dependent mechanism for inhibition by G0S2 on ATGL. However our data is not consistent with this hypothesis. There was no change in G0S2 protein content during an acute lipolytic inducing set of contractions in both whole muscle, and isolated mitochondria yet both ATGL and G0S2 increase following endurance training, in spite of the fact that there should be increased reliance on intramuscular lipolysis. Therefore, inhibition of ATGL by G0S2 appears to be regulated through more complicated intracellular or post-translation regulation.

Determination of the sevoflurane sparing effect of methadone in cats

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

Growth and metabolism of pacu (Piaractus mesopotamicus Holmberg 1887) juveniles fed diets containing different protein, lipid and carbohydrate levels

To verify the potential of lipids and carbohydrates to spare dietary protein and to understand the intermediary metabolism of interaction of these nutrients in pacu juveniles, an experiment was carried out to evaluate pacu physiological and performance parameters. The experimental design was completely randomized with 12 treatments in a 2 x 2 x 3 factorial arrangement, consisting of diets containing two digestible protein levels (200 and 230 g kg(-1) PD), two lipid levels (40 and 80 g kg(-1)) and three carbohydrate levels (410, 460 and 500 g kg(-1)). Fish-fed 230 g kg(-1) digestable protein (DP) showed increased glycaemia, decreased hepatic glycogen, as well as a smaller intake index and better feed conversion ratio. The higher dietary lipid level (80 g kg(-1)) reduced protein intake and serum protein concentration, increased liver and body fat content, but did not affect growth. At a lipid level of 80 g kg(-1), the increase in dietary carbohydrate levels promoted greater weight gain (WG), crude protein intake (CPI) and better feed conversion ratio (FCR). For fish fed diets containing 40 g kg(-1) lipid, the best energy-productive values (EPV) were obtained at 460 g kg(-1) carbohydrate. Increased levels of the main nutrients in the diets reduced the levels of serum triglycerides, while the increase in energy concentration increased the hepatosomatic (HSI) and glycaemia index values. Pacu used lipids as effectively as carbohydrates in the maximization of protein usage, as long as dietary protein was at a level of 230 g kg(-1) DP. The physiological parameters indicated that the best balance between the DP, dietary lipid and carbohydrate levels within the ranged this trial was obtained at 230, 40 and 460 g kg(-1), respectively, without lower growth.

Calories or protein? The effect of dietary restriction on lifespan in rodents is explained by calories alone

Acknowledgements JRS was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (grant XDB13030000), a ‘1000 talents’ professorship from the Ministry of Science and Technology (MOST) of the Chinese government, and a Wolfson award from the Royal Society. SEM was supported by the US National Institute of Health grant R01AG043972 and MM was supported by a TWAS studentship of the Chinese Academy of Sciences, during the preparation of this manuscript. We are grateful to three anonymous referees for their constructive and helpful comments.

Preparation of low protein latex : Effect of different cure systems and fillers on its properties

Natural rubber latex, an aqueous colloidal dispersion of polyisoprene is widely used in production of gloves, catherers, rubber bands etc. The natural rubber latex content present in products such as gloves causes allergic problems. Of the different types of allergies reported, latex is known to produce Type I and Type IV allergies. Type I is called immediate hypersensitivity and type IV is called delayed hypersensitivity. It has been reported that some of the proteins present in the latex are mainly responsible for the allergic reactions type I. Significant reduction in the allergic response (type I) of natural rubber latex can be achieved by the reduction in its protein content, however out of the total proteins present in the latex or latex film only a fraction is extractable. The major techniques employed to reduce protein content of latex include leaching, autoclaving, chlorination, use of proteolytic enzymes and use of non ionic surfactants. Sulphur vulcanization of dipped products is responsible for Type IV allergy. N-nitrosamine, a carcinogenic substance is produced as a result of sulphur vulcanization. Radiation vulcanization can be used as an alternative for sulphur vulcanization. The current research deals with techniques to reduce the allergy associated with latex products. To reduce the type I allergy, low protein latex is developed using polyethylene glycol, a non- ionic surfactant. The present study employs radiation vulcanization to eliminate type IV allergy. The effect of different cure systems and fillers on the properties of low protein latex is also investigated as a part of the study.

Effects of processing on physical characteristics of diets with distinct levels of carbohydrates and lipids: the outcomes on the growth of pacu (Piaractus mesopotamicus)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho produtivo e respostas fisiológicas de juvenis de cachara (Pseudoplatystoma reticulatum) alimentados com diferentes níveis de proteína e carboidrato

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Níveis de carboidratos e lipídios em dietas para juvenis de tambaqui (Colossoma macropomum): variáveis produtivas, fisiológicas e turnover isotópico

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

Fine tuning of on-growing diets for farmed marine fish species as a key tool to sustain the aquaculture development

The aim of this thesis was to investigate some important key factors able to promote the prospected growth of the aquaculture sector. The limited availability of fishmeal and fish oil led the attention of the aquafeed industry to reduce the dependency on marine raw materials in favor of vegetable ingredients. In Chapter 2, we reported the effects of fishmeal replacement by a mixture of plant proteins in turbot (Psetta maxima L.) juveniles. At the end of the trial, it was found that over the 15% plant protein inclusion can cause stress and exert negative effects on growth performance and welfare. Climate change aroused the attention of the aquafeed industry toward the production of specific diets capable to counteract high temperatures. In Chapter 3, we investigated the most suitable dietary lipid level for gilthead seabream (Sparus aurata L.) reared at Mediterranean summer temperature. In this trial, it was highlighted that 18% dietary lipid allows a protein sparing effect, thus making the farming of this species economically and environmentally more sustainable. The introduction of new farmed fish species makes necessary the development of new species-specific diets. In Chapter 4, we assessed growth response and feed utilization of common sole (Solea solea L.) juveniles fed graded dietary lipid levels. At the end of the trial, it was found that increasing dietary lipids over 8% led to a substantial decline in growth performance and feed utilization indices. In Chapter 5, we investigated the suitability of mussel meal as alternative ingredient in diets for common sole juveniles. Mussel meal proved to be a very effective alternative ingredient for enhancing growth performance, feed palatability and feed utilization in sole irrespectively to the tested inclusion levels. This thesis highlighted the importance of formulating more specific diets in order to support the aquaculture growth in a sustainable way.

Effect of nitrate and ammonium on the growth and protein concentration of Microcystis viridis Lemmermann (Cyanobacteria)

Cyanobacteria are a very important group in aquatic systems, particularly in eutrophic waters. Therefore studies about their success in the environment are essential. Many hypotheses have tried to explain the dominance of Cyanobacteria, and several emphasized the importance of various nitrogen sources for the success of the group. In this study, we measured the effect of ammonium and nitrate on the growth and protein concentration of Microcystis viridis (Cyanobacteria). This species is well-known because bloom formation in eutrophic waters. The study was carried out, in experimental batch cultures, using the WC medium with different nitrogen sources: ammonium, nitrate, ammonium + nitrate (50% ammonium + 50% nitrate) and ammonium at different concentrations (to test for possible NH4+ toxicity). Protein, ammonium and nitrate concentrations were measured at end of each experiment, whereas samples for cell counts were taken daily. Results showed that Microcystis viridis grew faster with ammonium (µ = 0.393 day-1) than with nitrate (µ = 0.263 day-1) and ammonium + nitrate (µ = 0.325 day-1). This pattern is explained by the metabolism of ammonium that presents higher uptake and assimilation rates than nitrate. Maximum cell concentration, however, was higher in the ammonium + nitrate treatment, followed by nitrate treatment. Higher protein concentration were observed in the treatment with nitrate. In the ammonium toxicity test, no difference between the control and NH4+ at 50% was found. Thus, the ammonium concentrations used in these experiments were not toxic. Our results suggest that Cyanobacteria is able to grow on both nitrogen sources even if ammonium may allow faster growth and bloom development.

Effect of intraperitoneally administered hydrolyzed whey protein on blood pressure and renal sodium handling in awake spontaneously hypertensive rats

The present study evaluated the acute effect of the intraperitoneal (ip) administration of a whey protein hydrolysate (WPH) on systolic arterial blood pressure (SBP) and renal sodium handling by conscious spontaneously hypertensive rats (SHR). The ip administration of WPH in a volume of 1 ml dose-dependently lowered the SBP in SHR 2 h after administration at doses of 0.5 g/kg (0.15 M NaCl: 188.5 ± 9.3 mmHg vs WPH: 176.6 ± 4.9 mmHg, N = 8, P = 0.001) and 1.0 g/kg (0.15 M NaCl: 188.5 ± 9.3 mmHg vs WPH: 163.8 ± 5.9 mmHg, N = 8, P = 0.0018). Creatinine clearance decreased significantly (P = 0.0084) in the WPH-treated group (326 ± 67 µL min-1 100 g body weight-1) compared to 0.15 M NaCl-treated (890 ± 26 µL min-1 100 g body weight-1) and captopril-treated (903 ± 72 µL min-1 100 g body weight-1) rats. The ip administration of 1.0 g WPH/kg also decreased fractional sodium excretion to 0.021 ± 0.019% compared to 0.126 ± 0.041 and 0.66 ± 0.015% in 0.15 M NaCl and captopril-treated rats, respectively (P = 0.033). Similarly, the fractional potassium excretion in WPH-treated rats (0.25 ± 0.05%) was significantly lower (P = 0.0063) than in control (0.91 ± 0.15%) and captopril-treated rats (1.24 ± 0.30%), respectively. The present study shows a decreased SBP in SHR after the administration of WPH associated with a rise in tubule sodium reabsorption despite an angiotensin I-converting enzyme (ACE)-inhibiting in vitro activity (IC50 = 0.68 mg/mL). The present findings suggest a pathway involving ACE inhibition but measurements of plasma ACE activity and angiotensin II levels are needed to support this suggestion.

Effect of the unfolded protein response on MHC class I antigen presentation

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Effect of protein, carbohydrate, lipid, and selenium levels on the performance, carcass yield, and blood changes in broilers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)