Effect of feeding different protein to energy (P/E) ratios on the growth performance and body composition of Oreochromis niloticus fingerlings

Abstract

SummaryThis study evaluated the growth performance and body composition of Oreochromis niloticus fingerlings (average initial weight 16.53 ± 0.44 g) fed 9 experimental diets (A, B, C, D, E, F, G, H and I) containing three different levels of protein (26, 31 and 36 g 100 g )1 ) at three different gross energy (GE) levels (16, 19 and 22 MJ kg) for a period of 64 days. Significant differences were observed in the feed consumption, body weight gain, specific growth rate (SGR), condition factor (k), feed conversion ratio (FCR), protein efficiency ratio (PER), net protein retention (NPR) and apparent net energy retention (ANER) values of fish when the energy level of diet was increased at different protein levels. The maximum weight gain, SGR and k were observed on diet F containing 36% protein and an energy level of 19 MJ kg )1 of dry feed with a protein to energy (P ⁄ E) ratio of 18.96 (g protein MJ )1 GE). A further increase in the energy content of the diet (22 MJ kg )1 ) at the same protein level (Diet I) did not produce any improvement in the growth performance. Lowering the energy level at the same protein level significantly affected the growth performance. Fish fed diet B containing 31% protein and a lower energy level of 16 MJ kg )1 with the same P ⁄ E ratio of 18.61 as diet F showed significantly lower weight gain and growth performance than diet F. Diets E and H containing 31% crude protein at all three energy levels produced similar results as diet B. The poorest FCR was observed when the diet contained both lower levels of protein and energy. Fish fed diet G, containing 26% protein at high energy level (22 MJ kg ). The body moisture content at all protein levels decreased (P < 0.05) with the increasing level of dietary energy whereas the body fat content increased (P < 0.05). Similar trends were observed in the body ash and energy content. Increasing the dietary energy content at lower protein levels did not show any difference (P > 0.05) in body protein content. Our results indicated the optimum P ⁄ E ratio for O. niloticus as 18.96 g protein per mega joule of gross energy at 36% dietary protein level and a dietary gross energy value of 19 MJ kg )1.

Growth of Nile tilapia post-larvae from broodstock fed diet with different levels of digestible protein and digestible energy

“…Some studies have reported the relevance of the balance between protein and energy in fish diets (Bomfim et al, 2005;Cotan et al, 2006;Piedras et al, 2006;Ali et al, 2008). If this ratio is unbalanced during fish growth, the proteins in the diet can be used as energy source (Kubitza, 2000) or directed to protein metabolism (Meurer et al, 2002).…”

Effect of dietary protein on the growth of mullet, Chelon labrosus, reared in sea cages

“…The present findings also indicated a considerable reduction in PER with carp feed. An increase in the dietary energy level at lower dietary protein levels improves the efficiency of protein utilization and retention (Ali et al 2008). Therefore, this reduction in carp feed probably results from the low lipid content or the types of vegetable proteins, as is mentioned above.…”

The growth of eel fed with different protein level and protein-energy ratio

“…Proses ekskresi dan katabolisme asam amino tersebut membutuhkan energi yang banyak sehingga alokasi energi protein untuk meretensi protein dalam tubuhnya akan berkurang. Retensi protein dipengaruhi oleh berbagai faktor termasuk kandungan protein pakan, keseimbangan asam amino dan rasio energi pakan (Ali et al, 2008). Respons penurunan laju pertumbuhan ikan akibat protein tinggi dilaporkan terjadi pada ikan sidat A. japonica dan A. marmorata yang mengalami kenaikan laju pertumbuhan pada kadar protein 45% dan menurun pada kadar 50% (Okorie et al, 2007;Cheng et al, 2013).…”