Ingestão de ração e comportamento de larvas de pacu em resposta a estímulos químicos e visuais

Abstract

RESUMO -Este estudo foi realizado com o objetivo de comparar a influência dos estímulos visual e/ou químico de náuplios de Artemia e de dieta microencapsulada sobre a taxa de ingestão da dieta microencapusulada por larvas de pacu Piaractus mesopotamicus. Utilizou-se um esquema fatorial 7 x 4 (estímulos e idades) com duas repetições. Verificou-se efeito da idade das larvas e dos estímulos, mas não houve efeito para a interação idade × estímulos. O estímulo químico da Artemia e ambos os estímulos da Artemia resultaram em maior taxa de ingestão de dieta inerte. Resultado intermediário foi obtido com o estímulo visual da dieta microencapsulada. O estímulo químico, em comparação ao estímulo visual da Artemia, resultou em maiores taxas de ingestão da dieta. Com o aumento da idade, houve incremento na taxa de ingestão. Os estímulos visual e químico dos náuplios e o estímulo visual da ração aumentaram a ingestão de dieta inerte por larvas de pacu. Náuplios de Artemia devem ser oferecidos antes do fornecimento da dieta inerte, pois podem auxiliar no processo de transição alimentar. Os resultados deste trabalho apontaram novas possibilidades de estudos com larvas de peixes neotropicais visando a substituição precoce do alimento vivo para o inerte. Palavras-chave: Artemia, comportamento, estímulo alimentar, larva, pacu, Piaractus mesopotamicus Diet ingestion rate and pacu larvae behavior in response to chemical and visual stimuliABSTRACT -The effect of visual, chemical and the combination of both stimuli from Artemia nauplii and from microencapsulated diet on dry diet ingestion by pacu Piaractus mesopotamicus larvae was evaluated in this research. The experiment was analyzed as a 7 x 4 factorial arrangement (seven stimuli and four ages) with two replicates. It was observed effect of larvae age and stimuli, but no interaction (age × stimuli) was observed. The chemical effect from Artemia and both effects from Artemia resulted in higher ingestion rates. An intermediary result was obtained with visual effect from microencapsulated diet. The chemical stimulus from Artemia resulted in higher ingestion rates than that obtained with Artemia visual stimulus. Ingestion rate increased as age increased. Chemical and visual stimuli from nauplii and visual stimuli from diet increased microencapsulated diet ingestion by pacu larvae. Artemia nauplii offered before the artificial diet may assist weaning. These results opens new study possibilities with Neotropical fish larvae precocious weaning.

Stable carbon (δ13C) and nitrogen (δ15N) isotopes as natural indicators of live and dry food in Piaractus mesopotamicus (Holmberg, 1887) larval tissue

“…The free choice of this particular dry diet (A+D‐larvae) was also evident from the 12th to 18th day onwards, albeit the A+D‐larvae continued preferably selecting live food, even being efficiently able to use the dry diet as a food source. More expressive intake of dry diet occurred later, when they definitively switched to the D‐larvae isotopic signal, in agreement with results that showed that pacu larvae increased the ingestion rates of dry diet as they became older (5–17 days) (Tesser & Portella 2006). Nevertheless, the relative contribution of the formulated diet in the isotopic composition of the animal's tissues with time may be influenced by the quality of the diet (nutritional and physical characteristics), ingestion and assimilation.…”

“…The isotopic results of the δ 13 C and δ 15 N obtained in pacu larval tissue made it possible to complement and clarify the information obtained previously at our laboratory (Jomori 1999, 2005; Jomori, Carneiro, Malheiros & Portella 2003; Tesser & Portella 2003, 2006; Macedo‐Viegas et al 2003; Jomori, Carneiro, Martins & Portella 2005; Tesser et al 2005, 2006). It was clearly shown that pacu larvae preferably ingest Artemia nauplii during the first 12 days of exogenous feeding even in the presence and availability of this specific formulated diet.…”

Effect of Salinity on Larval Rearing of Pacu, Piaractus mesopotamicus, a Freshwater Species

“…However, pacu larviculture is still considered a limiting factor for juvenile production. In our laboratory at the Aquaculture Center, Brazil, we have been studying pacu intensive larviculture for several years (Jomori et al 2003, 2005, 2008; Tesser et al 2005, 2006; Tesser and Portella 2006; Leitão et al 2011). Some advantages of pacu intensive larviculture have been demonstrated in comparison to semi‐intensive culture.…”

Combination of diet and water salinity in larviculture of piabanha-do-Pardo ( Brycon vonoi , Lima 2017)

“…Such fact occurs because these animals have underdeveloped digestive and enzymatic systems at this stage of life. Moreover, inert food is barely perceived, arousing less interest from larvae compared to live baits (Tesser & Portella, 2006). However, Brycon sp.…”