Replacement of soybean meal by peanut meal in diets for juvenile Nile tilapia, Oreochromis niloticus

The use of alternative feeds aims to maintain productivity and reduce animal production costs. This objective of this study was to determine the nutritional value of peanut meal (PNM), as well as replacement of soybean meal (SBM) by PNM in diets for Nile tilapia, Oreochromis niloticus. To determine the apparent digestibility coefficients (ADC) of nutrients from the PNM, 40 fish (100 +/- 4.3 g) were randomly distributed in four 250 L tanks and fed reference and test diets (50% PNM) plus 0.1% chromic oxide. Feces were collected by modified Guelph system. For the growth performance trial, 180 fish (13.4 +/- 0.2 g) were randomly distributed in 30 200 L tanks and fed during 90 days with isoproteic (26.8% digestible protein) and isoenergetic (17.6 kJ g(-1) digestible energy) diets containing replacement levels of 0, 25, 50, 75 and 100% of SBM digestible protein by PNM digestible protein. The experimental design was completely randomized with five treatments and six replicates. The ADC for protein from PNM was 90.9% whereas the ADCs for essential amino acids ranged from 88.7% for lysine to 97.6% for arginine. The feed conversion ratio was significantly affected when the SBM was totally replaced by PNM. The protein efficiency ratio, protein retention and whole-body protein content significantly decreased in fish fed diets containing PNM levels above 25% of PNM. Therefore, PNM can replace up to 25% of SBM without impairing juvenile Nile tilapia growth performance, feed efficiency, and body composition.