Ponderal evolution, food efficiency ratio and protein net efficiency ratio, determined in wistar rats fed diets with different protein sources

This study examined the viability of acid silage of Nile tilapia (Oreochromis niloticus (Linnaeus) on nutritional indices of Wistar rats: weight gain (GP), dietary intake (ID), food efficiency ratio (QEA) and relative protein net efficiency ratio (RNPR). Diets using silage obtained after 30 days and 90 days of storage were compared with diets containing casein, NUVILAB and aproteic diets. During 15 days (5 for adaptation and adjustments and 10 for samples), 40 male rats, weighing on average 61.42 + 3.09g, were housed in metabolic cages, followed by a completely randomized experimental design with five isoproteic and isocaloric diets, of which protein content (10.3 + 0.07% of protein) was supplied by casein, new silage, old silage, autoclavable Nuvilab CR-1 (unpurified diet closed formula of Nuvital Nutrients Ltda) containing (22.5% of protein) and aproteic diet as protein sources and 8 repetitions. There was a significant difference (p <0.05) for weight gain (GP), dietary intake (ID), food efficiency ratio (FER), protein net efficiency ratio (PNER) and relative protein net efficiency ratio (RPNER), which could establish a linear comparison between weight gain of rats and their time in the respective diets, in days. Then, a diet consisting of tilapia acid silage harvest during30 days had better quality than those stored for 90 days, being diets containing proteins as casein and Nuvilab superior and aproteic diets did not present satisfactory results.