Đánh giá tiềm năng đạm chiết xuất từ lá lục bình như là một nguồn đạm trong thức ăn của cá rô phi

Leaf protein concentrate extracted from water hyacinth (WH-LPC) regarded as potential plant protein to supplement in tilapia feed through two trials. In trial 1, WH-LPC was extracted by acid and heat coagulated method at acidification at pH lower than 4.0, thermal precipitation at 500C and rinsing with water. The obtained WH-LPC was evaluated for conversion rate as well as gross composition. In trial 2, to determine alternative level of WH-LPC to soybean in formulated feed for tilapia cage culture. There were seven treatments that included commercial feed and six replacing level of WH-LPC 0%, 5%, 10%, 15%, 20% and 25% crude protein in formulated feed containing 30 % crude protein. Nile tilapias (Oreochromis niloticus) (average weight 8.0 g) were stocked at 30 fish per cage (1x1x1m). The trials were designed by randomized complete block design.The result of trial 1 shown that WH-LPC and protein yields obtained 0.047g dry matter and 0.017g crude protein 100 g-1 fresh water hyacinth biomass, respectively or 0.43 g dry matter and 0.15 g crude protein 100 g-1 fresh leaf water hyacinth respectively. In addition, proximate compositions of WH-LPC were analyzed at 35.99% crude protein, 1.49% crude lipid, 8.89% ash and 12.69 % crude fiber.The result of trial 2 presented that WH-LPC could completely substitute soybean meal in tilapia formulated feed which could give better growth performance, survival rate and utilizing efficiency of protein of Nile tilapia. However, fish fed diets containing most of plant protein were less growth performance and efficiency of feed utilization than fish fed commercial feed (P<0.05).