Protein sources and digestive enzyme activities in jundiá (Rhamdia quelen) Fontes protéicas e atividade de enzimas digestivas em jundiás (Rhamdia quelen)

• Main Authors: Rafael Lazzari, João Radünz Neto, Fabio de Araújo Pedron, Vania Lucia Loro, Alexandra Pretto, Carolina Rosa Gioda
• Format: Article
• Language: English
• Published: Universidade de São Paulo 2010-01-01
• Series: Scientia Agricola
• Subjects: digestão; nutrição; farelo de soja; farinha de carne e ossos; farinha de peixe; digestion; nutrition; soybean meal; meat and bone meal; fish meal
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000300002

Digestive enzymes activity influence feed utilization by fish, and its understanding is important to optimize diet formulation. This study reports the digestive enzyme activities of jundiá juveniles fed diets with protein sources. Fish were fed six experimental diets for 90 days: MBY (meat and bone meal + sugar cane yeast), SY (soybean meal + sugar cane yeast), S (soybean meal), MBS (meat and bone meal + soybean meal), FY (fish meal + sugar cane yeast) and FS (fish meal + soybean meal), and then sampled every 30 days and assayed in two intestine sections for digestive enzymes - trypsin, chymotrypsin and amylase - activities; gastric protease was assayed in the stomach. Digestive and hepatosomatic index, intestinal quotient, digestive tract length and weight gain were also measured. Trypsin and chymotrypsin activities were higher (p < 0.0001) in fish fed diets containing animal protein sources (MBY, MBS, FY and FS diets). Alkaline proteases were negatively affected by dietary soybean meal in the SY and S diets. Amylase activity had greater variation between diets and intestine sections. Fish fed MBY and MBS diets showed higher gastric protease activity (p < 0.0001). Weight gains were higher in fish fed the MBS and FS diets (p < 0.05). Highest values (p < 0.05) of digestive tract length were observed in fish fed MBS and FY diets, but no correlation with enzymes activities was found. Hepatosomatic index (HSI) was affected by diet composition. Dietary composition influenced digestive enzymes activities of jundiá.<br>As enzimas digestivas influenciam a utilização dos alimentos em peixes, e seu conhecimento é importante para otimizar a formulação de dietas. Este trabalho descreve a atividade de enzimas digestivas em juvenis de jundiá alimentados com fontes protéicas. Os peixes foram alimentados com seis dietas (90 dias): MBY (farinha de carne e ossos + levedura de cana), SY (farelo de soja + levedura de cana), S (farelo de soja), MBS (farinha de carne e ossos + farelo de soja), FY (farinha de peixe + levedura de cana) e FS (farinha de peixe + farelo de soja). A cada 30 dias, foram analisadas as enzimas digestivas (tripsina, quimiotripsina e amilase) no intestino. No estômago, foi mensurada a protease ácida. Foram estimados os índices digestivo e hepato-somático, quociente intestinal, comprimento do trato digestório e ganho em peso. As atividades de tripsina e quimiotripsina foram maiores (p < 0,0001) nos peixes alimentados com as dietas com fontes de origem animal (MBY, MBS, FY e FS). As proteases alcalinas foram afetadas negativamente pelo farelo de soja nas dietas. A atividade de amilase apresentou grandes variações. Os peixes alimentados com as dietas MBY e MBS apresentaram maior atividade de protease ácida (p < 0,0001). Os ganhos em peso foram maiores nos peixes alimentados com as dietas MBS e FS (p < 0,05). Os maiores valores (p < 0,05) de comprimento do trato digestório foram verificados nos peixes alimentados com as dietas MBS e FY. A composição da dieta influencia na atividade de enzimas digestivas do jundiá.