Desempenho do piauçu (Leporinus macrocephalus) arraçoado com dietas contendo diferentes teores de tanino

Abstract

RESUMO -Este estudo foi conduzido com o objetivo de avaliar o efeito dos taninos sobre o desempenho produtivo e a composição da carcaça do piauçu. Utilizaram-se 21 aquários (80 L) num sistema de fluxo fechado com circulação continua (vazão de 1 L/min), filtro biológico e temperatura controlada. Empregaram-se 84 peixes com peso médio inicial de 5,06 g, na densidade de quatro por aquário, num delineamento inteiramente casualizado com sete tratamentos e três repetições. As rações foram formuladas de forma a apresentarem-se isoenergéticas (3200 kcal ED/ kg de ração) e isoprotéicas (30% PB), com as seguintes composições de tanino total: 0,00; 0,23; 0,46; 0,69; 0,92; 1,37 e 1,82. Avaliou-se a influência do tanino sobre o desempenho produtivo: ganho de peso, conversão alimentar aparente e taxa de eficiência protéica; a composição corporal dos peixes: proteína bruta da carcaça, extrato etéreo da carcaça, proteína bruta e extrato etéreo dos fígados e gordura visceral; e a relação hepatossomática: índice hepatossomático. Concluiu-se que, embora a presença de até 0,69% de taninos na ração não tenha comprometido os índices de conversão alimentar aparente e taxa de eficiência protéica das rações, níveis iguais ou superiores a 0,46% resultaram em ganho de peso significativamente inferior para o piauçu e que a espécie se mostrou sensível à presença de taninos condensados, os quais prejudicaram significativamente o metabolismo e o valor biológico dos nutrientes presentes nas rações.Palavras-chave: barbatimão, desempenho produtivo, Leporinus macrocephalus, piauçu, tanino Growth Performance of Piauçu (Leporinus macrocephalus) Fed Diets with Different Levels of TanninABSTRACT -This experiment was undertaken to evaluate the effect of dietary tannin on growth performance and carcass composition of piauçu, for sixty days. Twenty one aquaria (80 L) were supplied with dechlorinated tap-water (1 L/min) in a closed system. Water quality was controled by biologic filter and heater. Fish, with inicial average weight 5.06 g, in a triplicate aquaria, were randomly assigned to each of 7 treatments. Experimental diets were formulated to contain approximately 3,200 kcal of digestible energy, 30% crude protein and 0.0, 0.23, 0.46, 0.69, 0.92, 1.37 and 1.82% of total tannin. Although 0.69% of tannin added did not affected apparent feed conversion and protein efficiency ratio, concentrations equal or higher than 0.46% resulted lower weight gain. Piauçu was sensitive to condensed tannin which had significant harmful effect on metabolism and biological value of dietary nutrients.

Body lipid deposition in Nile tilapia fed on rations containing tannin

“…Castro et al (1998) verified no significant differences for proteic efficiency rate, when diets containing 20 and 40% sorghum for Nile tilapia were used in comparison with a commercial diet. Pinto et al (2001) utilizing condensed tannin levels, among 0.23 and 1.82%, in diets for "piauçu", observed that the proteic efficiency rate was harmed, starting at 0.92% tannin in the diet, a level above the utilized in this work, which may confirm the antinutritional action of this substance.…”

“…Diets containing tannin provided high protein levels, and significant interaction (p<0.05) between sorghum varieties and tannic acid levels was observed; moreover, diets containing tannic acid presented great proteic deposition in the body. Pinto et al (2001) also observed increase in the protein level of "piauçu" carcasses due to tannin level in the ration, showing linear growth with the coefficient of correlation equal to 82%.…”

“…However, Freire (2002) observed worse feed conversion rates in tilapia fed on diets containing sorghum with high tannin (condensed). Pinto et al (2001) utilized different condensed tannin levels in food for fry of "piauçu", and verified that rates of tannin up to 0.69% did not damage significantly the apparent feed conversion. In a study utilizing diets containing tannin rates from 0.27 to 1.08%, for common Table 1.…”

“…The plasmatic cholesterol levels were reduced 40% by the inclusion of 24% of sesbania (Sesbania aculleata) seed meal in diets for carp, compared to diets without tannin (Hossain et al, 2001b). Pinto et al (2001) observed an increase in fat excretion, in the feces, as well as a lower lipid deposit in the carcass, viscera and liver in "piauçu", after using low condensed tannin levels in rations.…”

“…The "piauçu" (Leporinus macrocephalus) fingerlings fed on diets containing different tannin levels had their performance evaluated by Pinto et al (2001). After 60 days, the "piauçu" showed sensitiveness to condensed tannins, which significantly damaged the metabolism and the biological value of the nutrients present in the rations.…”