Practical diet with total replacement of fishmeal by soybean meal for Nile tilapia: growth performance and health effects

Abstract

This study aimed to evaluate the growth performance and animal health in juveniles of Nile tilapia (Oreochromis niloticus) fed a practical diet with total replacement of fishmeal (FM) by soybean meal, as well the effect on survival, following pathogenic challenge with Aeromonas hydrophila. Two hundred juveniles of Nile tilapia were stored in 8 tanks (800 L). The experiment consisted of two treatments: a commercial diet formulated with FM (control) and a practical diet with total replacement of FM by soybean meal (SM). The variables of water quality, zootechnical and hematological parameters were measured. In addition, at the end of the experiment, the fish were submitted to a challenge with A. hydrophila. Higher cost per kg of fish was obtained in the control treatment (with FM). N retention was higher in fish fed a diet without FM, while hematological, immunological parameters and survival after the experimental challenge did not differ between treatments. It is possible to reduce dietary costs by replacing FM with SM without affecting growth performance or animal health, in addition to benefiting the environment by reducing the excretion of N in water.

Influence of taurine on the zootechnical performance and health parameters of juvenile Nile tilapia in a recirculating aquaculture system

“…Other studies have revealed similar data, with a low growth rate and high feed conversion in rainbow trout (Oncorhynchus mykiss)(Belghit et al 2014) and yellowtail (Seriola dorsalis) (Garcia-Organista et al 2019), requiring the addition of this amino acid in crystalline form(Browdy et al 2012, Michelato et al 2018, Nunes et al 2014. Therefore, growth performance is also correlated with methionine level in the diet, which, despite being below the recommended level for the species, good results can be justified by the sum of "methionine + cysteine", because the data obtained in this research are similar to those of fish produced with a commercial diet(Stockhausen et al 2022)…”

“…The mixture was then homogenized in a horizontal paddle mixer for 4 minutes and ground again to a size of 800 µm. It was then extruded at 105 °C using an extruder (FERRAZ®, Ribeirão Preto, SP, Brazil) with a capacity of 3000 kg h -1 , producing 3 mm diameter extrudates, according to the methodology used by Stockhausen et al (2022).…”

“…The present experiment involved two treatments (Table I): a control diet, formulated with practical ingredients and devoid of fish meal (Stockhausen et al 2022), and a taurinesupplemented diet, which contained the same practical ingredients and was supplemented with taurine at a level of 9.7 g kg -1 of feed (Al-Feky et al 2016). Both diets were isoproteic and isoenergetic and formulated to meet the nutritional requirements of tilapia, as outlined by the NRC (2011).…”