Thursday, April 20, 2017

21/04/2017: Feather meal to replace fishmeal by half in Nile tilapia diet

Hydrolyzed Feather meal is widely used in fish feeds
by Franz-Peter Rebafka, GePro Gefluegel-Protein Vertriebsgesellschaft mbH & Co. KG 

The material is rich in crude protein but its amino acid profile is not balanced, its digestibility is poor very often and some of its amino acids are destroyed during the drying process of the meal.

Gepro, Germany, has developed a drying process at low temperature that decreases the destruction rate of the amino acids in the feather meal. The improved product is called Goldmehl® FM.

Trials done on shrimps and some fish species, demonstrated that it can successfully replace some of the fishmeal in aqua-feed, without any detrimental effect on the performance.

This article explains the trial that was carried out by Nam Sai Farms Co. Ltd., Thailand for Gepro Gefluegel-Protein Vertriebsgesellschaft mbH & Co. KG to test whether GoldMehl®FM can replace fishmeal in practical diets for Nile tilapia reared in hapas in earthen ponds.

Materials and Methods
In a previously drained and disinfected earth pond of 1 rai (pond 10, Nam Sai Farm, Tambon Ban Grabow, Ban Sang, Prachinburi, Thailand), 15 x 5 m2 hapas (1 mm mesh) were installed and stocked with 300 1” Nile tilapia fry of 0.2 g initial body mass (total 4,500 fish). The fish were initially fed on powdered feed with a crude protein content of 30 percent at a rate of 5-10 percent body weight per day divided into three feeds.
Table 1: Feeding schedule

The amount fed was calculated subsequent to biweekly sampling and fed at a set rate for the whole period. After a period of four weeks, small pellets, consisting of the same ingredients as the powdered test diets, were added in increasing amounts until the fish were fed entirely on pellets only (Table 1).

The weaning period took one week. Five isonitrogenous test diets, in which Goldmehl® FM (supplied by GePro) is used to replace 0%, 25%, 50%, 75% and 100 percent of fish meal, was compared in triplicate to test their effect on growth and health performance of stocked juvenile tilapia (Tables 2 & 3).

An inclusion rate of 3:7 fishmeal:soybean meal was used in supplying protein to the control diet, as this is typical of most commercial tilapia diets. The total culture period was 12 weeks.

Hapa change was carried out after six weeks of culture, and the fine-meshed 5m2 hapas were all replaced with 10m2 4mm meshed hapas, which allow for better water exchange.

Read the full article HERE.

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