The banded cichlid (Herus severus) is an Amazonian species with potential as ornamental fish, however basic handlings as quantity and feeding frequency as well as stocking density in larviculture are still unknown in order to allow the rational production of this species in captivity. Then the objective was to evaluate the amount of food, feeding frequency and stocking density during the larviculture of Herus severus. Therefore, two experiments were conducted: the first assessed the food concentration (100, 150, 200, 250 and 300 Artemia larvae-1) and feed rate (2 or 4 meals day-1), and the second experiment evaluated different stocking densities (1, 5, 10, 15, 20 larvae L-1) with four replications each. Feeding of 250 nauplii larva day-1 distributed in four daily meals promoted the highest weight, length, specific growth rate, weight gain and survival. In the second experiment, reduction in growth was observed with increased in density due to lower concentrations of dissolved oxygen and elevated total ammonia from 5 larvae L-1. Thus, to promote the rational cultivation of the Banded cichlid larvae in captivity, the species should be reared at 5 larvae L-1 fed with 250nauplii distributed along 4 daily meals.
The study evaluated productive performance of larvae Nannostomus beckfordi submitted to feeding management (Experiment one) and different stock density (Experiment two) in captivity conditions. The first experiment evaluated feeding rate (100 and 200 nauplii of artemia larvae −1 day −1 ) and feeding frequency (2 and 4× per day). Second experiment evaluated different stock density (1, 5, 10, 20, 40 larvae per litre). At the end of 15 days, for both experiment, the survival and productive performance such as total length (TL), final weight (FW), specific development rate (SDR), specific growth rate (SGR), uniformity for weight (UW) uniformity for length (UL) and relative condition factor (Kr) was determined. For the main results, there is no significant difference to the rate and feeding frequency. The stock density has no significant difference for UW, Kr and survival. Nonetheless, a reduction in the TL, FW, SDR, SGR and FW with the increase in density (20 for 40 larvae per litre) was observed. Thus, for this species Nannostomus beckfordi during to initial stage using exogenous feeding, it is recommended 20 larvae per litre fed with 100 nauplii per larvae having two meals per day.
RESUMO: A fitoterapia vem sendo utilizada em criação de peixes a fim de promover estabilidade no ambiente de cultivo e na profilaxia de doenças, contribuindo para melhoria do bem-estar animal. Dentre os fitoterápicos, a canela (Cinnamon zeylanicum) possui atividade antioxidante, antiinflamatória, antifúngica e antiparasitária, além de efeito imunoestimulante. O objetivo do trabalho foi avaliar os efeitos do extrato aquoso de canela sobre o desempenho produtivo de larvas do peixe ornamental amazônico Pyrrhulina brevis. Foram avaliadas cinco concentrações de extrato aquoso (0; 0,25; 0,50; 0,75 e 1,0 g/L) em 4 repetições, durante 20 dias. A utilização de 1,0g/L de extrato de Cinnamon zeylanicum favorece o desempenho produtivo das larvas, com melhores resultados para comprimento total final, taxa de crescimento específico para comprimento e promove 100% de sobrevivência ao lote (P<0,05). Este é o primeiro relato da eficácia do uso de extrato aquoso de canela como promotor de crescimento na larvicultura de peixes.Palavras-chave: fitoterapia, peixe ornamental, sanidade.
AQUEOUS CINNAMON EXTRACT AS A GROWTH PROMOTER FOR LARVAE OF THE ORNAMENTAL AMAZON FISH Pyrrhulina brevisABSTRACT: Phytotherapy has been used in fish farming to promote stability in the rearing environment and for the prophylaxis of diseases, improving animal well-being. Among phytotherapeutic agents, cinnamon (Cinnamon zeylanicum) exhibits antioxidant, anti-inflammatory, antifungal and antiparasitic activity, in addition to immunostimulatory effects. The objective of this study was to evaluate the effect of an aqueous cinnamon extract on the productive performance of larvae of the ornamental Amazon fish Pyrrhulina brevis. Five concentrations of the aqueous extract (0, 0.25, 0.5, 0.75 and 1.0 g/L) were evaluated in four replicates over a period of 20 days. The use of 1.0 g/L of Cinnamon zeylanicum extract favored larval performance, improving final total length and the specific growth rate in length and promoting 100% survival of the batch (P<0.05). This is the first study demonstrating the efficacy of the use of aqueous cinnamon extract as a growth promoter in fish larviculture.
The study tested the use of Artemia salina nauplii as first exogenous feeding in the larviculture of Hypancistrus sp. Moreover, we aimed to assess the quantity of prey concentrations and the stocking density during the first 30 days of feeding. Experiment I: larvae were fed with four initial prey concentrations, T100: 100, T200: 200, T300: 300 and T400: 400 A. salina nauplii/larvae/day. The quantity of A. salina nauplii increased every six days to adequate the larval growth. Experiment II: larvae were kept at four stocking densities, 1, 5, 10 and 15 larvae/L. In both experiments, the A. salina nauplii were consumed with success for the larvae. Best larvae growth and survival were observed with T400 in comparison to T100. In the Experiment II, the stocking density of 15 larvae/L showed higher ammonia (1.23 mg/L) and reduction of larvae growth and dissolved oxygen concentration (5.7 mg/L). The densities of 1 and 5 larvae/L provided the best results for growth. The stocking densities showed no differences for survival. Thus, we recommend the use of A. salina nauplii in the first feeding for larvae of Hypancistrus sp., at the initial prey concentration of 400 nauplii/larvae/day and stocking density of 5 larvae/L.
Symphysodon aequifasciatus is a fish with a disk-shaped body and bright colors, important characteristics of ornamental fish. We evaluated amino acid supplementation strategies to reduce crude protein in the diet for evaluation of performance, the content of digestive enzymes, liver metabolism, and intestinal histopathology. A total of 180 fish were randomly distributed in 12 separate 50 L glass aquariums, consisting of a completely randomized design with four treatments (DC - Control diet with 34.4% crude protein; DL - Control diet plus 1% of lysine; DEAA - Control diet plus 1% free essential amino acids (threonine, phenylalanine, leucine, valine, arginine, and tryptophan); and DHP - Diet with a high level of crude protein 48.4%), three repetitions, lasting 60 days. The use of DL and DEAA diets resulted in higher intestinal villus height and higher zootechnical performance. The use of DL diet increased alkaline phosphatase and digestive amylase activity. The use of DHP diets promotes severe liver changes due to increased activity of Alanine aminotraserase. Therefore, it was possible to observe that the use of amino acids can supply the nutritional need of blue discus. Supplementation of diets with AAs allows the reduction of dietary protein, which is a strategy for feeding management.
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