Harvest Time
Reduced tilapia feeding gives more income
By Dr. Sosimo Ma. Pablico
HERE’S GOOD NEWS for tilapia raisers – you may now reduce the amount of supplemental feed given to your fish and still get more income.
Aquaculture researchers at the Freshwater Aquaculture Center of the Central Luzon State University (FAC-CLSU) led by Dr. Remedios B. Bolivar have found that delayed feeding and alternate day feeding are effective strategies that reduce the amount spent for feed, resulting in increased income.
Normally, for every PhP10 spent in tilapia production growers spend PhP6 for feed.
These research results are among the significant findings of a collaborative project with scientists of the North Carolina State University (NCSU) in the United States since 1982.
Generally known as a Collaborative Research Support Program (CRSP), the project has already assumed three names as follows: Pond Dynamics/Aquaculture CRSP (1982-1999), Aquaculture CRSP (2000-2005), and Aquaculture and Fisheries CRSP or AquaFish CRSP (2006-2011). It is one of the 11 CRSPs that were created to link the capabilities of US agricultural universities with the needs of developing countries.
Dr. Bolivar of the FAC-CLSU is the host country principal investigator in the Philippines, while Dr. Russell J. Borski of NCSU is the CRSP US lead principal investigator. The project is funded by the US Agency for International Development (USAID), NCSU and CLSU.
Dr. Bolivar said the idea of delayed feeding is not new, as Thai researchers led by Dr. J. Diana found in 1966 that delayed feeding could save some cost of production without affecting fish yield. A considerable savings could be achieved if this feeding strategy is applied on a large scale.
The CRSP study at FAC-CLSU was conducted in seven farms. Each participating farm allowed the use of two ponds, which were stocked with sex-reversed GIFT (genetically improved fast growing tilapia) strain of Nile tilapia at an initial density of 4 fish per square meter.
Each pond was fertilized weekly with inorganic fertilizer at the rates of 28 kg nitrogen (N)/ha and 5.6 kg phosphorus (P)/ha. These rates are equivalent per hectare to 51 kg urea (46-0-0) and 28 kg ammonium phosphate (16-20-0). Fertilization was needed for the production of algae (lablab) which the fish consumed before the start of supplemental feeding.
In their experiment, FAC-CLSU researchers started giving supplemental feed to the fish at 45 and 75 days after stocking. Supplemental feeding continued until harvest at 150 days after stocking.
The results showed that while fish given supplemental feed starting at 45 days after stocking weighed heavier at harvest (average of 164 grams), they also consumed more feed amounting to 8,299 kg/ha. This amount of feed was 2,231 kg/ha more than the consumption of fish given supplemental feed starting at 75 days after stocking.
Based on data provided by Dr. Bolivar to this writer, the total value of feed consumption starting at 45 days after stocking until harvest (PhP235,110/ha) was 81 percent of the total production costs of PhP334,100/ha. On the other hand, the total value of feed consumed starting at 75 days after stocking until harvest (PhP171,906/ha) was almost 78 percent of the total production costs of PhP320,190/ha.
Computed per hectare, delayed feeding starting at 75 days after stocking resulted in a higher net return of PhP99,133. In contrast, a net return of only PhP44,332/ha was obtained from delayed feeding starting at 45 days after stocking.
In the alternate day feeding strategy, supplemental feed is given to the fish every other day. In other words, feed is not given the day after the provision of supplemental feed.
In their study, Dr. Bolivar and her team compared daily feeding with alternate day feeding to determine if indeed the cost of producing tilapia could be significantly reduced without significantly reducing fish production. Supplemental feeding started at 45days after stocking.
As in the study on delayed feeding, this trial also showed that while fish in the daily feeding strategy had a heavier weight at harvest (average of 167 grams), they also consumed more feed (6,331 kg/ha) than those in the alternate feeding strategy (2,807 kg/ha).
As a result, the total value of feed consumption in the daily feeding strategy (PhP163,339/ha) was a lot higher than that consumed in the alternate feeding strategy (PhP69,376/ha). These data mean that the value of feed consumed in the daily feeding strategy was almost 73 percent of the total production costs, while that in the alternate feeding system was only 58 percent.
In the final analysis, the daily feeding strategy even resulted in a negative net income of minus PhP30,166/ha. In great contrast, a net return of PhP62,435/ha was realized from the alternate day feeding strategy.
Try them and you’ll be amazed at the results.
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