International Journal of Aquaculture, 2016, Vol.6, No.12, 1
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are also scarce since the nutrient profile of a feed determines the growth performance of fish; this study was
designed to determine the nutrient level of stored feed using the prevalent method of storage among fish farmers
in Benue state Nigeria.
2 Materials and Methods
Eight kilograms of each of Coppens
®
, Multifeed
®
and vitalfeed
®
was purchased from a reputable feed store along
the modern market road, Makurdi Nigeria. They were divided into two halves (4kg) and stored in open and
airtight conditions for six months. The open condition was done by widely opening the feed packaging from the
top and left open to the atmosphere for the period of 6months. The airtight condition was created by open the feed
packaging from the top however, it was squished together and tied with a rope to provide a simple airtight
condition of storage. The choice of these methods of storage for this study was based on a pre-field survey done
on the packaging style of most fish farmers around the state. Samples of the feed were collected one a month for
different nutrient analysis. Proximate analysis of feeds was determined using the methods of AOAC, (2000).
Parameters measured (in percentage) include moisture, ash, crude fiber, ether extract and crude protein. Nitrogen
Free Extract (NFE) was determined by the difference between 100% and the other parameters. Organoleptic
description of the feeds before, during and after the storage period was done by a team of previously trained
assessors using hedonic scales designed for the study (reference).
Peroxide value (POV) and Free Fatty Acid (FFA) analysis were also done according to AOAC, (2000), oils with
POV well below 10 mg/kg are considered fresh. While oils with POV between 20-40mg/kg were termed rancid.
Mould growth was identified according to the method described by APHA (1998).
3 Results and Discussion
The crude protein content of Coppens
®
under airtight condition remains fairly constant during a storage period of
six months, while that of Multifeed
®
was reduced a little as the time of storage prolonged (Table 1; Table 2; Figure
1). The same trend was observed for Vitafeed
®
(Table 3; Figure 1). This could be as a result of protein aging as
postulated by Shyong, (1998); however deviation of the trend of decrease observed in Coppens
®
may be due to
differences in feed ingredient suggesting that the susceptibility of feed to the "protein aging" phenomenon may
differ with different feedstuffs. Hossen et al., (2011) reported that changes in the chemical composition and
nutritive value of feed may occur during storage. Though the protein content of all commercial feeds stored in
open condition reduced as the storage time increased, the marginal decrease recorded in airtight conditions (Figure
1) is an indication that nutrient deterioration may be reduced with proper storage practices. This observation
agrees with Jones, (1987)and Lim et al., (2008) who reported that infestation of feed by spoilage microorganisms
results in loss of dietary nutritional value owing to loss of amino acids (especially lysine and arginine), dietary
lipids, and vitamins.
Figure 1 Monthly changes in percentage crude protein content of Coppens
®
, Multifeed
®
and Vitalfeed under airtight and open
conditions stored for the period of six months
