ABSTRACT. Triploid fish are usually sterile. Thus, the energy and nutrients intended for sexual maturation may be available to enhance flesh quality and physical growth. The present study aimed to investigate differences in the metabolic substrates, lipids and proteins, between storage tissues from diploid and triploid female rainbow trout. Monthly, metabolic substrates were quantified in liver, muscle, and ovaries, which were collected during the first reproductive cycle. In general, it was possible to identify a seasonal and similar deposition of metabolites in different tissues of 2n and 3n females, mainly at early stages of gonadal maturation. However, from the stages 5-6, the ovaries showed great differences between ploidies, with higher concentration of lipids and protein in 2n females. This result reflects the incorporation of vitellogenin in oocytes, which is a process that does not occur in 3n females. It was possible to observe seasonal hepato-somatic index changes in 2n females, with higher values observed in the post-ovulatory stage, and the triploid animals showed lower values compared to 2n, with no seasonal difference. Viscero-somatic index can reflect the mobilization of substrates, with higher values found for 2n females in stage 5-6, which is the period of active mobilization of tissue substrates.

Resumo Objetivo: O balanço de massa tem sido aplicado recentemente na aquicultura brasileira. Em relação à truticultura, poucos trabalhos têm utilizado essa metodologia como indicador ambiental, notadamente quando se considera cada fase de desenvolvimento. O balanço de massa diário permite a estimativa da descarga de nutrientes, pois o esforço amostral ao longo de 24 horas possibilita monitorar as oscilações ao longo do dia. O objetivo deste estudo foi identificar o setor de criação em truticultura (alevinos, juvenis e adultos) que contribui com o maior aporte de fósforo e nitrogênio no efluente. Métodos As concentrações de fósforo total (PT), ortofosfato (P-PO4), nitrogênio total (NT) e íon amônio (N-NH4) foram determinadas no afluente e nos efluentes do sistema de produção. Os indicadores ambientais foram calculados com base nos valores das cargas de nutrientes e por meio de quantificação da descarga diária de nutrientes pelo método de balanço de massa. Resultados No decorrer de 24 horas, a truticultura exportou em média 0,26 kg PT, 0,11 kg P-PO4, 3,11 kg NT e 0,18 kg N-NH4. A descarga de fósforo e nitrogênio no efluente foi mais elevada durante o período noturno, associada aos horários e frequência de arraçoamento e ao hábito noturno das trutas. O balanço de massa mostra que os setores de juvenis e adultos foram responsáveis pelo maior aporte desses nutrientes, relacionados à maior biomassa de peixes e metabolismo, corroborado pela taxa de conversão alimentar de 1,95:1 e 2,01:1, respectivamente. Conclusão Para reduzir as exportações de fósforo e nitrogênio há necessidade de adequar o manejo alimentar (frequência alimentar de duas a quatro vezes por dia considerando o estágio de desenvolvimento da truta; realizar alimentação em horários próximos ao crepúsculo devido ao hábito noturno da espécie; reduzir o excesso de ração oferecida e usar ração de boa qualidade considerando as exigências nutricionais distintas de cada estágio de desenvolvimento da truta). Além do balanço de massa, a taxa de conversão alimentar também é ferramenta eficiente para detectar a eficiência de utilização da ração. Portanto, propõe-se a sua utilização como indicador ambiental, visando à sustentabilidade ambiental da aquicultura.

Abstract Aim: The mass balance has recently been applied in Brazilian aquaculture. In relation to trout farming, few studies have used this methodology as environmental indicator, especially when considering each development stage of fish. The daily mass balance allows an estimate of nutrients discharge, because the sampling effort over 24 hours enables to monitor the variations throughout the day. This study aimed to identify the breeding sector (fingerlings, juveniles and adults) in trout farming contributes with the great discharge of phosphorus and nitrogen in the effluent. Methods The concentrations of total phosphorus (TP), orthophosphate (PO4-P), total nitrogen (TN) and ammonium (NH4-N) were determined in affluent and effluents of the production system. The environmental indicators were calculated based on the values of nutrients loads and by quantifying the daily discharge of nutrients from the mass balance method. Results Over the 24 hours, the trout farming exported an average of 0.26 kg TP, 0.11 kg PO4-P, 3.11 kg TN and 0.18 kg NH4-N. The discharge of phosphorus and nitrogen in the effluent was higher at night associated to feeding management (hours and feeding frequency) and the nocturnal habits of trout. The juvenile and adult sectors accounted for the greatest contribution of these nutrients, related the largest fish biomass and metabolism, supported by the feed conversion ratio of 1.95:1 and 2.01:1, respectively. Conclusion In order to reduce exports of phosphorus and nitrogen there is a need to adequate the feeding management (feeding frequency from two to four times per day according to the trout development stage; carry out feeding in times close at twilight due to the nocturnal habits of this specie; reduce excess of ration offered and use good quality ration considering the distinct nutritional requirements of each trout stage of development). Besides the mass balance, the feed conversion ratio is also an efficient tool to detect the efficiency of feed utilization; therefore, it is proposed its use as environmental indicator, aiming the aquaculture environmental sustainability.

A criopreservação do sêmen de fêmeas masculinizadas de truta arco-íris tem como objetivo a racionalização do processo de produção de estoques 100% femininos. Para tal, foi coletado sêmen de machos normais (M) e de dois tipos de fêmeas genotípicas (R e G), masculinizadas pela administração oral de 17alfa-metiltestosterona. R foi obtido pela fertilização de ovócitos normais com sêmen de fêmeas masculinizadas enquanto G foi através de reprodução ginogenética. O sêmen foi diluído em uma solução crioprotetora (glicose 5,4 g, gema de ovo de galinha 10 ml, dimetil sulfóxido 10 ml, água destilada 80 ml) na razão de 1:3 (sêmen/diluidor), envasado em palhetas de 0,5 ml e congelado em um "container" tipo "seco" Cryopac CP-65, à temperatura de -180ºC. A descongelação foi feita em água a 70ºC por 3 segundos. As taxas de fertilização obtidas, não revelaram diferença estatística significativa (P<0.05) entre os três grupos de sêmen descongelados (M = 73,1±11,5%; R = 67,2±23,6%; G = 64±5,8%), indicando que a metodologia de congelação utilizada foi eficaz, tanto na criopreservação do sêmen das trutas normais como para o das masculinizadas.

Cryopreservation of semen from sex-reversed females of rainbow trout aims at rationalizing the production of stocks composed by 100% females. Semen from normal males (M) and two types of genotypic females (R and G), sex-reversed by the oral administration of 17alpha-methyltestosterone, were used. R was obtained by the fertilization of normal eggs with semen of sex-reversed females while G via gynogenetic reproduction. Semen was diluted in an extender solution (glucose 5,4 g, egg yolk 10 ml, dimetil sulfoxide 10 ml, water 80 ml) at 1:3 ratio (semen/extender), stored in straws of 0.5 ml and freezed in a dry container Cryopac CP-65, at -180ºC. Thawing was performed with water at 70ºC for 3 seconds. There were no significant fertilization rate differences (P>0.05) among thawed semen groups (M = 73.1±11.5%; R = 67.2±23.6%; G = 64±5.8%), confirming that the freezing methodology used was efficient to cryopreserve semen of all three trout groups.

This Study was carried out at the Salmoniculture Experimental Station "Dr. Ascanio de Faria", in Campos do Jordão, São Paulo. Brazil. The aim was to compared the hematology of triploid and diploid rainbow trout, Oncorhynchus mykiss Walbaum, 1792, by sex and gonadal maturation stages. Blood was obtained from 144 individuais for determinati-ons of: haemoglobin rate (Hb), haematocrit (Ht), erythrocyte count (Er), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MHC), mean corpuscular hemoglobin concentration (MCHC), and differential leucocyte counts. The ploid was determinated by measuring the erythrocyte major axis, in fresh and stainncd smears. Triploid rainbow trout had a large eiythrocyte diameter, mean erythrocyte volume and mean haemoglobin concentration, but lower erythrocyte count than diploid. Lymphocytes was the most frequent cell in peripherical blood.There was no dilTerence between males and females for ali parameters here analysed. The haematological analyses showcd signiffleant increase with the dcvelopment of gonadal maturation stages.