Gutenborn, Germany (August 06, 2015) – Red snapper is a very popular dish. Along with its mild taste, it is loaded with protein and low in saturated fat and sodium. The popularity of red snapper has led to an unfortunate consequence. Red snapper populations in the wild are being depleted due to overfishing. To help replenish populations, experts are calling for large scale red snapper farming. Most of the existing red snapper farms are very small in scale. These farms are manned by local aquaculturists who have shown some success in raising red snapper and other fish species.
The objective of the trial what to evaluate the efficiency of functional feed Sanbio MARE added to normal diets for Red Purple Snapper (Lutjanus sp) fed compared to similar diets but without addition of Sanbio MARE. The trial was performed according to the Best Practice Guideline by targeting the sensitive parameter (mortality, weight gain, feed intake, feed conversion rate).
The SANBOS GmbH, in cooperation with local partners, conducted a tank feeding trial with Red Purple Snapper (Lutjanus sp). The objective of the trial was to demonstrate Snapper growth and performance in fresh-water tanks with a partial replacement of fish feed by the functional feed Sanbio MARE.
1. Materials and methods
Four cages of average size 8 m3 (underwater volume) at the cage fish farm were used for the feeding trial. Cages were constructed of nylon netting over a rigid cage frame and were individually fitted with an opaque cover and a feed enclosure to contain extruded, floating and slowly sinking feed pellets. Cage placement was at the perimeter of the cage farm, with a minimum spacing of two meters between and on all sides of each cage.
Fish were 230 g red purple snapper produced locally. Red purple snapper were stocked in the four trial cages on 30 March at a density of 900 fish per cage. Fish in all four trial cages were of uniform size, age and health status at stocking. Red purple snapper in the control cage were fed with 100% of standard marine growout feed in extruded, floating pellet form as per Table 1.
Red purple snapper in treated trial cages were fed with 80% of standard marine growout feed in extruded, floating pellet form as per Table 1 and 20% of Sanbio MARE as per Table 2. Fish were fed to satiation twice daily, with fish in all four cages fed identically at every feeding. Feed pellet size was increased as the fish grew so that the maximum size pellet that all fish could consume was being fed.
Trial management was based on the best practice and Sanbos GmbH standards.
Fish in all cages were sampled once per month on approximately the same date each month. At the conclusion of the trial, all cages were emptied and the fish in each cage counted and weighed to determine average fish weight, gross and net production, feed conversion ratio (FCR) and survival. Production input costs were recorded throughout the trial and net income and return on investment (ROI) were calculated at the end of the trial.
Table 1. Formula for the standard fish feed used in the trial
| Pellet size (mm) | 3 / 4.5 / 6 |
| Crude protein (%) | 42 |
| Crude fat (%) | 17 |
| NFE (%) | 22 |
| Ash (%) | 6 |
| Fibre (%) | 2.5 |
| P (%) | 1 |
| Gross energy (MJ) | 21 |
| Digestible energy (MJ) | 17 |
Table 2. Formula for the “Sanbio MARE” fish feed supplement used in the trial
| Pellet size (mm) | 3 / 6 |
| Crude protein (%) | 40 |
| Crude fat (%) | 10 |
| Ash (%) | 8 |
| Fibre (%) | 4.7 |
| P (%) | 1.5 |
| Amino acids | 5 |
| Vitamins | 1 |
| Carbohydrates | 5 |
| Minerals | 5 |
| Formate | 2.5 |
| Gross energy (MJ) | 22 |
| Digestible energy (MJ) | 18 |
2. Results
Red purple snappers were fed a total of 120 days between 30 March and 26 July 2015. Red purple snappers grew from 231 g to an average weight of 603 g (+15% compared to control) during this feeding period. Gross production averaged 414,39 kg per cage (+29% compared to control).
Average red purple snapper survival rate was 77,40% (+12% compared to control). Average FCR for red purple snapper was 1,96 (-7% compared to control).
Table 3. Productive performance
| Cage no. | Unit | 1 | 2 | 3 | 4 | Average 2/3/4 |
| Cage | Control | Trial 1 | Trial 2 | Trial 3 | ||
| No day fed | D | 120 | 120 | 120 | 120 | |
| Stocking rate | Fish/tank | 900 | 900 | 900 | 900 | 900.00 |
| Harvest rate | Fish/tank | 613 | 686 | 688 | 689 | 687.60 |
| Mortality | % | 31.9 | 23.8 | 23.6 | 23.4 | 23.60 |
| Survival | % | 68.1 | 76.2 | 76.4 | 76.6 | 76.40 |
| Fish stocking weight | g | 231 | 230 | 232 | 231 | 231 |
| Fish harvest weight | g | 526 | 605 | 601 | 602 | 603 |
| Weight gain | g | 295 | 375 | 369 | 371 | 371.7 |
| Specific growth rate | SGR | 0.69 | 0.81 | 0.79 | 0.80 | 0.80 |
| Production | kg/tank | 322.4 | 414.9 | 413.2 | 415.0 | 414.39 |
| kg/m3 | 40.3 | 51.9 | 51.7 | 51.9 | 51.80 | |
| Feed intake | kg/tank | 677 | 813 | 806 | 818 | 812.21 |
| FCR | 2.1 | 1.96 | 1.95 | 1.97 | 1.96 |
Figure 1. Productive performance (%)
3. Conclusion
To summarize, the present study shows significantly positive effects of SANBIO MARE at the dosage of 20% of diet on productivity.
The positive effects at a glance:
- Reduction of mortality
- Increase of weight gain
- Improvement of FCR
- Positive effects on health status
- Safety and tolerance when used dietary additions.