A survey on commercial fish feed used at Fulpur area in Mymensingh district

This study was performed in Fulpur upazila under Mymensingh district for the period of 13 months from August 2010 to August 2011 to know the socio-economic and aquaculture status of fish farm owners and to assess the nutritive value of commercial fish feed available at Fulpur upazila of Mymensingh district. Fish farm owners were prominent in the study area and majority was illiterate but had the ability of signature. The monoculture and polyculture farm in the studied area were established in ranged from 1995 to 2005, respectively. Most of the fish farm owners followed polyculture system and had small farm area. Majority of fish farm owners leased water body for aquaculture. The minimum size of the farm was 0.162 ha and maximum size of the farm was 3.722 ha. The average depth of the water body in winter season was 1.61 meter and in summer season was 2.32 meter. Majority of fish farm owners followed proper pre-stocking and post stocking management with maintaining high stocking density of fish and using either commercial or farm made fish feed. Among the commercial fish feed tested the highest value of moisture was found in Aftab feed, protein in Nourish feed, lipid in CP feed, ash in Aftab feed, fibre in ACI feed and carbohydrate in ACI feed. Most of the commercial fish feed maintain standard level of chemical composition.


Introduction
Bangladesh is very rich in inland capture fish production.But now-a-days capture fish production is decreasing day by day due to different causes.Such as agricultural pollution, industrial pollution, natural calamity etc. Fish of the beels along with other aquatic organisms are silent victims of chlorine sub-lethal toxicity resulting from different types of pollutants (Bernet et al., 1999).Fish production is also decreasing due to natural causes like flood, drought etc (Chakraborty, 2009).At present, total poultry and fish feed companies are 54 such as Saudi-Bangla Feed mill, Fresh Feed mill, Quality Feed mill, Nourish Feed mill etc and there are about 25 commercial fish feed industries in Bangladesh (Rob, 2008).The well-known industries are Al-Momen Feed mill, Aktel Feed Mill, Rahat Feed Mill etc in the Mymensingh region.Fish feed and feeding play important role in the sustainable development of aquaculture.Better feed composition will result in higher fish production and lower feed cost.In feed development, there should have a provision of continuous investigation of raw materials and feed management in the mills and industry.

Materials and Methods
Study area: This experiment was performed in Fulpur upazila under Mymensingh district.

Duration of the study:
The present study was undertaken for the period of 13 months from August 2010 to August 2011.

Preparation of questionnaire:
The questionnaire was prepared in accordance with the objectives of study.The questionnaire has two parts, one includes personal information and the other includes farm information.

Analytical methods:
The proximate composition of different commercial fish feeds were analyzed in duplicate according to standard procedure given in Association of Official Analytical Chemists (AOAC. 2000).

Moisture:
The percentage of moisture was calculated using the following equation:

Crude Protein
Crude protein of the samples was estimated by using Kjeltec 2020 digestor.A sample of 0.5 g and a blank was estimated in the digestion tube.For digestion at high temperature, 10 ml of concentrated sulfuric acid and 1.1 g digestion mixture were added in the tube.Then the digestion tubes were set in digestion chamber fixing at 420 0 C for 45 minutes ensuring water supply, easier gas outlets etc.After digestion the tubes were allowed to cool and 5 ml of sodium thio-sulphate (Na 2 S 2 O 3 , 33%) and 30 ml sodium hydroxide (NaOH) solution was added in each tube.Then the distilled extraction was collected with 25 ml of Boric acid (4%) and titrated with standard hydrochloric acid (0.2N).The nitrogen values obtained was converted into percentage of crude protein by multiplying with a factor of 6.25 assuming that protein contains 16% nitrogen.

Crude Lipid
Crude lipid was determined by extracting a weighed quantity (2-3 g) of samples with analytical grade acetone in ground joint Soxhlet apparatus.Extraction was allowed to continue by heating in the electric heater at the temperature of 70 0 C until clear acetone (without oil) was seen in siphon, which took about 3 hours.Then the round bottom flask of the apparatus was separated and the extract was transferred to a pre-weighed beaker and left for evaporation of acetone.After the evaporation of acetone, only the lipid was left in the beaker which was later calculated in percentage.

Crude Fibre
A small amount of finely ground sample (1-2 g) was taken into a filter crucible and was inserted into the hot extraction unit (Hot Extractor, Model-1017).Sufficient amount of pre-heated 0.128M H 2 SO 4 was added into the reagent heating system and few drops of octanol were added through the valves.The mixture was digested for 30 minutes.Acid was then removed from it by filtering and washing with boiling water.The residue in the flask was boiled with required amount of 0.223M KOH for 30 minutes and then filtered with subsequent washing in boiling water and acetone.The residual content was then dried in an oven at 105°C for a few hours and then ignited in muffle furnace at 550°C for 3 hours.The loss of weight represented the crude fibre.Then percent crude fibre was calculated by the following formula: Nitrogen Free Extracts (NFE) Nitrogen free extract (NFE), a soluble carbohydrate was calculated by subtracting the sum of the percentage contents of moisture, crude protein, lipid, ash and crude fibre from 100.Nitrogen free extract (NFE) was calculated as: NFE % = {100-(moisture + crude protein + crude lipid + ash + crude fibre)}

Processing and Analysis of Data
The collected data were summarized, tabulated and analyzed according to the objectives of the study.A tabular method of analysis was followed in analyzing the collected information.For data analysis MS Word, Excel and SPSS were used.

Results and Discussion
Marketing Type of Feed The marketing of feed was done in different ways.Some feeds were supplied in farm directly or via Dealer.The marketing chain of the company is given below by flow chart (Figure 1):

Fig. 1. Company feed marketing chain
Through the study, it was possible to gather information on availability and nutritive value of fish feeds at Fulpur of Mymensingh district.During the study period, proximate composition such as moisture, protein, lipid, ash, crude fibre and carbohydrate of different feeds were analyzed in the laboratory.Reports on the analysis of fish feeds are stated below:

Moisture
The mean moisture value of ACI fish feed, Nourish fish feed , Mega fish feed, Aftab fish feed, CP fish feed, Saudi Bangla fish feed and Quality fish feed are 11.77%, 10.38%, 10.06%, 17.72%, 11.76%, 10.95% and 12.93%, respectively.The maximum moisture was found in Aftab fish feed (17.72%) and the minimum was in Mega fish feed (10.06%).

Crude Protein
The mean crude protein value of ACI fish feed, Nourish fish feed , Mega fish feed, Aftab fish feed, CP fish feed, Saudi Bangla fish feed and Quality fish feed are 23.15%,31.67%,24.24%, 25.85%, 23.74%, 26.65% and 23.92%, respectively.The maximum crude protein content was found in Nourish fish feed (31.67%) and the minimum crude protein was in ACI fish feed (23.15%).