Glycerol inclusion in the diet of Nile tilapia (Oreochromis niloticus) juveniles

Abstract

The present study evaluated the effects of inclusion of glycerol in the diet of Nile tilapia juveniles on growth performance, biochemical changes in blood, and carcass composition. We used 300 Nile tilapia juveniles with an average initial weight of 29.15 ± 8.40 g and 11.55 ± 0.87 cm in length, distributed in 20 fiberglass tanks with a capacity of 250 L. The experiments followed a completely randomized design with five treatments and four replications during 79 days. The animals were fed diets containing four concentrations of glycerol (25 g kg À1 , 50 g kg À1 , 75 g kg À1 and 100 g kg À1 ) and a control diet without glycerol. HDL was the only biochemical parameter, that showed statistically different (P < 0.05) results; it was higher in the groups fed with 0 and 75 g kg À1 glycerol compared to the other groups. No significant difference was observed in the results from the carcass composition of tilapia juvenile fed with the different glycerol levels, except for lipids (P < 0.05), which showed the highest values in fish fed with 50 g kg À1 glycerol and the lowest in fish fed with 100 g kg À1 . Glycerol can be used in fish diets as an energy supplement without causing damage to growth performance or to the biochemical and carcass composition of Nile Tilapia juveniles.

Growth and energy metabolism of Nile tilapia juveniles fed glycerol

“…These results corroborate those of Neu et al (2013), who did not find any difference in the growth performance of Nile tilapia fed different levels of dietary glycerol. Li et al (2010) showed that the use of up to 10% dietary glycerol for channel catfish (Ictalurus punctatus) did not cause changes in weight gain, feeding efficiency, hepatosomatic index, and survival.…”

“…The present study shows that glycerol might be a potential energy source in Nile tilapia feeding, corroborating Meurer et al (2012) and Neu et al (2013). Menton et al (1986) suggested that rainbow trout were not efficient in using glycerol as an energy source.…”

“…The difference between these results could be due to the different dietary habits of the studied fish species, since Nile tilapia is an omnivorous fish and has relative facility to metabolize dietary carbohydrates (Enes et al, 2009). In addition, the yield and use of glycerol as a dietary energy source varies according to animal species and size (Neu et al, 2013). Further studies are needed to trace more accurately the glycerol route in fish metabolism.…”

“…However, little is known about its inclusion in Nile tilapia (Oreochromis niloticus) diet. Neu et al (2013) demonstrated that diets containing up to 100 g kg -1 glycerin did not affect carcass composition and growth performance of Nile tilapia juveniles. Gonçalves et al (2015) found lower weight gain in Nile tilapia juveniles fed 160 g kg -1 glycerin than in those fed 40 and 80 g kg -1 .…”

Uso de trigo orgânico na alimentação de juvenis de tilápia do Nilo

“…Por isto, diversos ingredientes alternativos são utilizados na ração (Boscolo et al 2002, Neu et al 2012, com a finalidade de reduzir custos e determinar um crescimento satisfatório, similar ao obtido com alimentos convencionais. Os alimentos orgânicos se distinguem dos demais por possuírem apelo agroecológico, pois são 1.…”