Applied Research Sample for students

ABSTRACT

A randomized complete block experiment on feeding milkfish (Chanos chanos Forsskal) fed with formulated diets from local materials containing conventional and non-conventional sources of protein  was conducted in  Zamboanga del Sur, Philippines.  Main feedstuffs used in the diets were: local fishmeal, soya meal, Leucaena leucocephala (ipil-ipil) leaf meal, Manihot esculenta (cassava) leaf meal, and ricebran. The milkfish were fed isonitrogenously for 90 days starting at the 109^th day of culture (DOC) up to 208 DOC at 4.0 % feed rate. The pelletized feed was formulated to be cheap (Feed X=PhP9.12/kg; Feed Y=PhP8.92/kg) with low-protein diets (Feed X=23.3%CP; Feed Y=23.8%CP). The control diet is a high protein commercial pellet feed (Feed Z=37.3% CP) at PhP25.00/kg. Final average body weight (g) of fish on diets X, Y and Z  was 265 ±4.8, 259 ± 6.1 and 274±6.5, respectively. Weight gain (g) in diets X and Y were 156±4.8 and 150 ± 6.1, which was significantly less (p<0.05, n=9) than diet Z (165±6.5). The growth  with Feed X seemed better than Feed Y but the difference was not significant (p>0.05). Total weight (g) of fish produced by Feed X per cage (3,987±72.4) was almost similar to Feed Y (3,888±91.0),  while fish produced in Feed Z was significantly higher (4,119±97.7). The total supplemental feeds (g) given per treatment were: diet X, 9 007±678; diet Y, 8 151±129 and diet Z, 4 902±36, respectively.  Significant differences were observed in feed conversion, i.e. Feed X and Y had significantly higher FCR than Feed Z. In terms of protein efficiency ratio (PER), Feed Z was most efficient (p>0.05) than both Feed X and Y but Feed Y was more efficient than Feed X.  This study has  demonstrated  that a diet producing lesser growth was the diet producing greater profit.  Hence, Feeds X and Y are more cost-effective than Feed Z.

Feedstuffs used were readily available in the farm

INTRODUCTION

Commercially available fish feeds for use in the modified extensive farming systems are very costly to the aquafarmers in Zamboanga del Sur. This is due to the use of inappropriate feeds and poor feeding management. The said province, situated between the latitudes 7°16’ and 8°20’ N and longitude 122° 14’ and 123°14’ E, has an area of 48,090 ha  classified as wetlands, of which 32,992 ha is brackishwater. The latter is the largest in the country but it is sad to note that the province also appears to be the lowest in terms of aquaculture productivity.

In 1997 an aquaculturist in the province had demonstrated a 3-fold increase in yield from the normal level of production in the province (496 kg/ harvest) by increasing the stocking density to 6,000 fingerlings.  However, in 100 days of culture (average body weight was 80-85 g/fish) natural food in the pond was overgrazed. Commercial feeds were then used as supplement.  Moreover, the return on investment was not  encouraging due mainly to the high cost of supplemental feeds.  The landed cost of feed from Ozamis City (about 95 km) or Cagayan de Oro City (about 250 km) to Pagadian City reached 50 to 80% of the cost of production. Further, with  additional costs due to hauling and the poor farm-to-market road conditions, profits were severely diminished.  To address this problem, an appropriate feed type to match the farming system should be formulated and  locally processed to be cost effective.  For this, several factors have to be considered including:  (1) the technical expertise in operation management,  (2) the farm infrastructure (e.g., pumps, aerators, feeding equipment, farm and pond size, etc.), (3) the desired yield, and (4) the farm-to-market road situation.

For the purpose of this study, the researcher has adopted the Modified Extensive Culture System (MODEX) as categorized by SEAFDEC Aquaculture Department, Philippines.  The optimum stocking density here is 4,000– 6,000 milkfish/ ha (Cruz, 1996), food supply is mainly natural but with supplemental energy-rich food, and yields range from 1,000 – 2,000 kg/harvest per hectare (Sumagaysay & Borlongan, 1995). One of the fishponds operated by the Arandela’s,  Zamboanga del Sur was   chosen and prepared for this experiment using the method.

Objective

            It is a common experience by the fishpond operators in the province that only around 350-500 kg/ha per crop is attainable in their extensive farming system.  Beyond this limit, natural food is overgrazed and any increase in the desired production level can only be realized through the use of supplemental food sources.  The present study is intended to formulate a  diet using locally available materials that will sustain the growth of the fish in the  modified extensive culture system of Chanos chanos.  Such diet must be cost-effective  at  PhP8.50 –12.00 /kg feed.

Significance

 The farther the feed miller (Manila and Cebu) and the source of feed  to the end users (Zamboanga del Sur), the higher the cost of feeds. With this, profitability increases if locally available raw materials are used  and the compounded feeds are processed locally. In most cases, supplementary feeds are formulated for general use regardless of the cultured species to increase productivity, but this research believes that profitability is more important to the farmers.

in remote areas feeds are better processed right in the site

RESULTS

Growth of fish and Feed Consumption

The test diets (Feed X,Y and Z) had metabolizable energy of 2.75, 2.80 and 3.38 kcal/g as fed basis, respectively. Growth of milkfish, feed given (assumed as consumed since the fish were seen eating the feeds before the feeds reached at the pond bottom) and other related parameters that describe the performance of the test diets are shown in Table 4.  In diets with conventional source of protein, fish given with Feed X, (wherein the main source of protein is the local fish meal at 60.08% CP), had significantly less (p<0.05, n=9) weight gain than that of the control feed Z.  Final weight of fish on diets X, Y and Z  was 265 ±4.8, 259 ± 6.1 and 274±6.5, respectively. The growth  with Feed X seemed better than Feed Y but the difference was not significant (p>0.05).

Feeding and monitoring

Fish produced by Feed X was almost similar to Feed Y,  while fish produced in Feed Z was significantly higher in mean body weight at harvest than both of the test diets. The total supplemental feeds  given per treatment (g) were: diet X, 9 007±678; diet Y,  8 151±129 and diet Z, 4 902±36, respectively.  Significant differences were also observed in  feed conversion i.e.  Feed X and Y had significantly higher FCR than Feed Z. In terms of protein efficiency ratio (PER), Feed Z was significantly more efficient (p>0.05) than both Feed X and Y.

during sampling and weighing to get the average body weight

Initially, in the first formulation of the experimental diet vitamin pre-mix and Spirulina were included.  However, with these inclusions the compounded feeds became very expensive. It  reached more than the control feeds (PhP25.00). Since the objective is to formulate a practical diet within PhP8.50 to PhP12.00, the Spirulina were not used then. Hence, the  final cost of feeds was only  PhP9.12 for Feed X and  PhP8.92 for Feed Y.  

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