Nile tilapia broodfish fed high‐protein diets: Digestive enzymes in eggs and larvae

The aim of this study was to assess the activity of gastric, pancreatic and intestinal digestive enzymes during the embryonic and larval development of Nile tilapia (Oreochromis niloticus) GIFT strain Aqua America® 1 obtained from a broodstock fed two levels of crude protein (CP). A total of 72 females and 24 males, 10 hapas, two CP levels (32% and 38%) and six phases of embryonic (cleavage, blastula, gastrula) and larval (hatching, 7 and 10 days post hatch, dph) stages were used. The eggs were collected in cleavage, blastula and gastrula stages, 300 mg was collected, and kept in cryogenic tubes in liquid nitrogen. For the samples at larval stage, the remaining eggs were separated according to crude protein level and kept in hatcheries and samples were collected on 7 and 10 dph the same way as before. A total of 48 samples were collected: at each protein level (32% and 38% CP), four samples were collected in each phase of embryonic and larval development. Statistical differences were not observed during embryonic development for acid proteases, trypsin, amylase and lipase activity at both levels of crude protein (32 and 38% CP). Differences for acid proteases were noticed on 7 dph; trypsin and amylase on 7 dph and 10 dph. Significant differences on blastula and 7 dph for protease; as for aminopeptidase, there was significant difference on 7 dph. The data indicated early appearance of digestive enzymes in Nile tilapia broodfish receiving 32% CP taking into account the rapid growth and development of this species.info:eu-repo/semantics/acceptedVersio

Desenvolvimento e diferenciação dos ovócitos de pacu, <em>Piaractus mesopotamicus</em> (Holmberg, 1887) (Osteichthyes, Characidae) Oocyte development and differentiation in pacu, <em>Piaractus mesopotamicus</em> (Holmberg, 1887) (Osteichthyes, Characidae)

O objetivo deste trabalho foi o de esclarecer dúvidas referentes ao desenvolvimento e à diferenciação dos ovócitos de <em>Piaractus mesopotamicus</em> (Osteichthyes, Characidae), ultra-estruturalmente, acompanhando as transformações que ocorreram durante o processo de ovogênese tais como: formação e acúmulo de várias organelas, inclusões nucleares e/ou citoplasmáticas e a camada ou envelope folicular. Na fase de crescimento primário são evidentes os corpúsculos de Balbiani, mas não são claros seus papéis. Estão presentes, também, as peculiares estruturas lamelares. A segunda fase, a de crescimento secundário, caracteriza-se, inicialmente, pela formação de alvéolos corticais. A seguir, os grânulos de vitelo protéico formam-se na região periférica com abundância de mitocôndrias e ribossomos. Mudanças no epitélio folicular (granulosa) são descritas concomitantemente com a formação da zona radiata, que constitui o envoltório folicular (envelope).<br>This work aim is to clarify doubts about the <em>Piaractus mesopotamicus</em> (Osteichthyes, Characidae) oocyte ultrastructural development and differentiation, following the transformations during the ovogenic processes, such as formation and accumulation of various organelles, nucleolar and/or citoplasmic inclusions, and follicular wall (envelope). During the primary growth phase, Balbiani corpuscles are evident, but their role is not clear. The peculiar lamellae structures are also present. The second phase (secondary growth) is initially characterized by cortical alveolus formation. After that, protein yolk granules appear in the peripherical regions, where mitochondria and ribosomes are abundant. Changes in the follicle epitelium (<em>granulosa</em>) are described together with the radiate zone formation, which constitutes the follicular envelope

Desempenho produtivo de Pseudoplatystoma corruscans estocados em sistemas de criação: semi-intensivo (viveiro escavado) e intensivo (tanque-rede)

Objetivou-se comparar o desempenho produtivo e custos de produção de exemplares de pintado, Pseudoplatystoma corruscans, estocados em dois sistemas de criação: semi-intensivo (viveiro escavado, VE) e intensivo (tanque-rede, TR). Trezentos (300) peixes, com um ano de idade, foram estocados, sendo 150 em um VE (médias de peso e comprimento: 1,48±0,46kg e 57,31±6,42cm) e 150 divididos em três TR (médias de peso e comprimento: 1,27±0,34kg e 55,05±4,11cm). Foram alimentados com ração extrusada de 15mm (diâmetro) 40% PB e 3110kcal ED kg-1, ajustada mensalmente à quantidade de ração. Os parâmetros físico-químicos da água, observados durante o experimento, foram temperatura = 24,08°C±3,23; pH=6,89±0,39 e oxigênio dissolvido = 7,57±0,97mg L-1. Os reultados obtidos dos valores médios finais dos comprimentos (VE=74,07±4,34cm; TR=70,33±5,02cm) e pesos dos peixes (VE=3,41±0,58kg e TR=2,94±0,60kg) indicaram desempenho semelhante nos dois sistemas. As médias do fator de condição (0,09-0,036); ganho em peso diário (9,29g dia-1 - 8,95g dia-1); conversão alimentar (3,09-4,15); consumo total de ração (29,60g dia-1 - 74,16g dia-1); índice de crescimento (0,219-0,215) e sobrevivência (97,33-90,67%) para VE e TR, respectivamente. Houve interação significativa entre os sistemas de criação e mês (P<0,05). O quilo de peixe produzido foi de R$8,76 (US$ 2,85) e R$8,73 (US$ 2,33) para o VE e TR, respectivamente. Embora o VE tenha demonstrado melhor desenvolvimento durante o período e uma vantagem econômica, o índice de crescimento mostrou que ambos os sistemas tiveram desempenhos semelhantes.The objective of this study was to compare the growth performance and cost of production of Pseudoplatystoma corruscans stocked in two culture systems: semi-intensive (ponds, P) and intensive (cage, C). From three hundred (300) one-year-old fish, one hundred fifty (150) were stocked in one pond (mean weight and length 1.48±0.46kg and 57.31±6.42cm), one hundred fifty (150), distributed in three cages (mean weight and length 1.27±0.34kg and 55.05±4.11cm). The fish were fed with extruded commercial ration with 15.0mm floating pellets containing 40% crude protein (CP) and, 3,110Kcal of digestible energy (DE), adjusted monthly. The parameters of water were: temperature = 24.08°C; pH=6.89; dissolved oxygen = 7.57mg L-1. The values of mean final length (P=74.07±4.34cm; C=70.33±5.02cm) and final weight (P=3.41±0.52kg; C=2.94±0.60kg) they showed similar development in both systems. Means of factor condition - K - (0.009-0.036); daily weight gain - DWG - (9.29g day-1-8.95g day-1); feed conversion- FC - (3.09-4.15); Total ration consume - TRC - (29.6g day-1-74.16 g day-1); growing index - IC - (0.219-0.215); survival - S - (97.33-90.67%) for P e C, respectively. Through the variance of analysis can be verified that there are significative interactions of the parameters between the culture systems and months (P<0.05). The produced weight of fish was R$8.76 (US$ 2.85) and R$8.73 (US$ 2.33) for P and C. Although P showed best performance during the period and economic vantage, the growing index demonstrated that both systems had similar development.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

<b>Características morfométricas e crescimento do cachara, <em>Pseudoplatystoma fasciatum</em> (Linnaeus, 1766), em cativeiro</b> - DOI: 10.4025/actascianimsci.v25i2.2002 <b>Morphometric characteristics and growth in cachara, <em>Pseudoplatystoma fasciatum</em> (Linnaeus, 1766) in captivity</b> - DOI: 10.4025/actascianimsci.v25i2.2002

Estudaram-se as características morfométricas e o crescimento de machos e fêmeas do cachara, <em>Pseudoplatystoma fasciatum</em> (Pimelodidae), em cativeiro. Os peixes foram distribuídos em 4 viveiros de 600m², na densidade de 1,0 peixe/2m². Dados de peso total (W_t /g), comprimento total (L_t/cm), padrão (L_s/cm), cabeça (L_h/cm) e altura do corpo (H_b/cm) foram obtidos bimestralmente, de janeiro/99 a janeiro/01, considerando-se 5% de cada lote. Foram analisados 132 machos e 248 fêmeas, que atingiram peso médio final, de 1.233,0g e 2.266,0g, respectivamente. A relação L_t/W_t apresentou alta correlação, com valores de b superiores a 3, onde o dimorfismo entre os sexos não foi observado. As relações L_t/L_s e L_t/L_h foram lineares, e para L_t /H_h obteve-se um melhor valor de b superior para as fêmeas. Não ocorreram diferenças entre os sexos para essas variáveis. O fator de condição não apresentou grandes variações sazonais.<br>Morphometric characteristics and growth of males and females of “cachara”, <em>Pseudoplatystoma fasciatum</em> (Pimelodidae), were studied. Fishes were distributed in four ponds (600m²), at the rate of 1fish/2m². Total weight (g), total length (cm), standard length (cm), head length (cm), body height (cm) were obtained bimonthly, from January/99 to January/01, from 5% of each pond population. One hundred thirty two males and two hundred forty eight females were analyzed showing an average final weight of 1,233.0g and 2,266.0g, respectively. The L_t/W_t relationship showed high correlation, with b values slightly above 3, where no sexual dimorphism was observed. The relationship L_t /L_s and L_t /H_l presented linear tendency with high correlation. For L_t /H_C, the females b values were higher than males. There were no differences between the sexes for those variables. Condition factor remained relatively constant without showing seasonal fluctuation

Danos causados a embriões de Piaractus mesopotamicus, em diferentes estádios de desenvolvimento, após técnica de resfriamento

The present study investigated the effects of 6h- and 10h-storage at -8ºC on the quality and hatch rate of Piaractus mesopotamicus embryos at 4 stages of development. Embryos were exposed to a cryoprotectant solution, cooled down at a rate of 1ºC.min-1 to -8ºC, and stored at this temperature for 6h and 10h, respectively. For control treatment, viable embryos at the 4 developmental stages studied, were selected and taken immediately to the incubator, without going through cooling. The results were evaluated using a multivariate statistical technique (factor analysis). Damage was characterized according to the following variables: uniformity, adhesion, symmetry, margins, and inclusion. Two factors that best explained the variance of each parameter were defined. The control group had the highest hatch rates, and a weak relationship with embryo damage. Although treatments involving 6h and 10h cooling exhibited lower hatch rates and a higher association to damage. The information obtained in this study is useful in promoting improved cryopreservation techniques for fish embryos, indicating the probable conditions under which certain injuries are more frequent.O presente estudo investigou o efeito da estocagem de embriões de Piaractus mesopotamicus em quatro diferentes estádios de desenvolvimento, durante 6 e 10 horas a -8ºC na qualidade e taxa de eclosão. Os embriões foram expostos à solução crioprotetora e passaram por curva de resfriamento de 1ºC.min-1 até atingir -8ºC, onde foram mantidos por 6 e 10 horas, respectivamente. Para o tratamento controle, embriões viáveis nos quatro estádios de desenvolvimento estudados, foram selecionados e levados a incubadoras, sem passar por resfriamento. Os resultados foram avaliados usando estatística multivariada (análise de fatores). Os danos causados pelo resfriamento foram caracterizados de acordo com as variáveis: uniformidade, adesão, simetria e bordas das células, além de inserção no vitelo. Foram definidos dois fatores que conseguiram reter maior variância contida nos dados. O grupo controle apresentou alta taxa de eclosão e baixa relação aos danos verificados nos embriões. Enquanto os tratamentos com 6 e 10 horas após resfriamento tiveram taxas de eclosão mais baixas e alta associação aos danos. Os resultados encontrados são importantes, pois indicam condições prováveis em que ocorrem lesões durante o processo de resfriamento das células, contribuindo assim para o aperfeiçoamento da técnica de criopreservação de embriõe

Chilling of Steindachneridionparahybae (siluriformes: pimelodidae) embryos

The objective of this study was to assess the viability of Steindachneridion parahybae embryos after chilling using different cryoprotectant solutions, stages of embryonic development, chilling curves, and storage periods at temperatures between -10 °C and 0 °C. Three experimental tests were conducted, and the following aspects were evaluated: (1) the toxicity of six cryoprotectant solutions (10% methanol, ethylene glycol, or DMSO combined with 0.5-M sucrose or lactose); (2) viability of embryos submitted to cooling with two cryoprotectant solutions (10% or 20% methanol combined with 10-M sucrose) at three different stages of development (closure of blastoporus, appearance of the optic vesicle and the moment when the tail began to straighten out), and two chilling periods (6 and 12 hours); (3) viability of embryos submitted to cooling with three chilling curves (directly to the freezer without a curve, 0.5 °C/min and 1.0 °C/min) and two chilling periods (6 and 12 hours). After the tests, it was concluded that the protocol which presented the most positive results after chilling, with a hatching rate of 63.50 ± 9.98% of the embryos and 12.32 ± 3.85% normal hatched larvae, was the one with embryos at the free-tail stage, the cryoprotectant solution with 10% methanol and 10-M sucrose, a chilling curve of 0.5 °C/min, stored for a maximum of 6 hours at subzero temperatures (temperature ranging between -5.05 °C and -7.83 °C).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

POST-COOLING DAMAGE TO Piaractus mesopotamicus EMBRYOS AT DIFFERENT STAGES OF DEVELOPMENT

The present study investigated the effects of 6h- and 10h-storage at -8ºC on the quality and hatch rate of Piaractus mesopotamicus embryos at 4 stages of development. Embryos were exposed to a cryoprotectant solution, cooled down at a rate of 1ºC.min-1 to -8ºC, and stored at this temperature for 6h and 10h, respectively. For control treatment, viable embryos at the 4 developmental stages studied, were selected and taken immediately to the incubator, without going through cooling. The results were evaluated using a multivariate statistical technique (factor analysis). Damage was characterized according to the following variables: uniformity, adhesion, symmetry, margins, and inclusion. Two factors that best explained the variance of each parameter were defined. The control group had the highest hatch rates, and a weak relationship with embryo damage. Although treatments involving 6h and 10h cooling exhibited lower hatch rates and a higher association to damage. The information obtained in this study is useful in promoting improved cryopreservation techniques for fish embryos, indicating the probable conditions under which certain injuries are more frequent. Keywords: cryopreservation, embryogenesis, multivariate analysis, South American fis