Biochemical study of trash fish for their utilization in Pakistan

The commercial and industrial catch of marine fishes generally consists of edible and inedible species. Among inedible species the bulk catches of small size fishes are also included and these small fishes are commonly referred to as trash fish or Low value fish . Therefore this research has been designed to evaluate the nutritive compound found in trash fish which is commonly catches along with the commercial and industrial catch of marine fishes. The moisture, crude protein, crude fat and calorific value were estimated by standard methods. The results were discussed in relation with the utilization of important compounds like protein, crude fat and amino acids in food, medicine and other commercial purposes.


INTRODUCTION
Low value or so-called "trash Fish" is a broadly used term that relates fish species that by virtue of their small size or low consumer preference have little or no commercial value [1][2][3][4][5] .They are used widely in coastal areas either directly for human consumption of as feeds for aquaculture and livestock [6][7][8] .Capture fisheries in the Asian region are increasingly landing these small species as quality of catch declines and there is a ready market for these fish 7 .It is reported that the by-catch production of marine fisheries in Thailand has been steady for more than 5 years.All low value fish and trash fish landed at the Shipu Fishing Port and the Dongzhao Fishing Port is fully utilized with almost none of this being wasted [8][9][10][11] .A significant proportion of fresh low value fish is consumed or utilized locally as part of household food security; some of them aroused for processing into human food products through drying, fermenting and salting, etc. by more One of the most important issues in fisheries all over the world is that of trash fish.Trash fish is a broad term, the meaning of which varies across countries and regions.In Malaysia the term trash fish applies to that part of the catch, which is not fit for direct human consumption, including undersized fish of commercially important species 18- 20 .An increasing share of trash fish in overall landings is an indication of gross over fishing.Excessive harvesting of juvenile fish will lead to growth over fishing.
So it is desirable to conduct studies to promote the applications of nutritive compounds of trash fish.This significant work was followed by a series of reports [12][13][14][15][16][17][18] .The present research provides the complete information of 13 -edible species of trash fish in terms of nutritional value, utilization and application in different by -products.

MATERIALS AND METHODS
The collection of Trash fish was procured bi -monthly from Karachi fish harbour in 2005, soon after the landing.The Trash fish immediately brought to the laboratory and thoroughly washed with tap water.
The edible species were identified by fin formula method ] and each species were dried separately for biochemical analysis.Moisture was determined by the standard method of Sinha 21
In protein content, a marked variation has been observed (   Figure showed (1-13) biochemical profile of thirteen edible trash species.From all these results it has been concluded that all the thirteen species studied have good value of nutritional contents and they can be easily utilized in diet and other by products such as fish fertilizer, fish protein concentrate and fishmeal, fish floor and Fish glue.Fish oil is commonly used in paints industry manufacturing of soap fungicids, insecticide in medicines and such as coronary diseases.
.The crude protein contents were determined by the Microkjeldahl distillation method.The total lipid was extracted by the soxhelet extraction method described by Triebold and Aurand (1963).Carbohydrate were determined by Anthron methode.The calorific values of the fish tissue were determined by the Parr bomb calorimeter by the given formula as (Ft -It) x H. Theq -Length of fused wire x cal / cm G.E = Weight of the sample G.E. = Gross energy Ft = Final temperature It = Initial temperature H. Theq = Hydrothemel equivalent.Its value is Constant and is 1832.Cal/cm = It is also a constant and its value is 2.3.