Nile tilapia is one of the most produced species worldwide, due to its high productivity and relatively easy husbandry. However, just like all producers of animals for human consumption, tilapia farmers are experiencing increasing feed costs. Improving the use and efficiency of raw materials is, therefore, interesting for the aquaculture sector. To reduce feed cost, the industries’ focus is on improving the efficiency of digestion and retention of energy, protein and fat, which are expensive components of the diet. In previous research, it was shown that the addition of a nutritional emulsifier (NE) based on glyceryl polyethyleneglycol ricinolate (GPGR), can improve Nile tilapia protein efficiency, fat digestibility, overall growth performance, energy efficiency and health status of the fish in a research environment (Wangkahart et al., 2022). However, more interesting is to evaluate the effect on a larger scale by doing an on-farm evaluation on the addition of a NE on fish survival, growth performance and feed efficiency.
The objective of this study was to investigate the effect of adding a NE at levels of 350 g NE/MT of feed on growth performance and feed efficiency. The experiment was performed in Thailand, with a duration of 97 days. The trial consisted of seven tanks with 1500 fish per tank where two dietary treatments were tested. Fish were fed ad-libitum three times per day. They were fed either the control diet, four repetitions, which was a local commercial tilapia feed, or the treatment diet, in triplicate, where NE was added to the local commercial Tilapia feed at levels of 350 g NE/MT of feed (Table 1). Amount of feed consumed was measured and summarized in the end as feed intake (FI). Next to that average start body weight (SBW), average final body weight (FBW), growth (G) and feed conversion ratio (FCR) were measured. Additionally, survival and health were monitored during the feeding trial.
Results showed that the addition of NE did not affect fish survival, health and FI. It can be observed that FBW and G was affected by dietary inclusion of NE (Figure 1; p<0.1). Tilapia fed NE were significantly bigger and grew significantly more compared to the fish not fed NE. Next to that, a positive trend towards FCR could be observed , where NE was shown to improve FCR slightly (Figure 1; p=0.161).
Previous research already showed that addition of a NE can increase feed efficiency and health status of Nile tilapia. This was confirmed by the feeding trial of this experiment. In general, it can be stated that adding a NE on farm scale can offer fish farmers a way to increase feed efficiency and, therefore, decrease feed cost.