Fishmeal is an important dietary ingredient for aquatic diets due to its ideal amino acid profile for most cultured species, excellent palatability and the availability of polyunsaturated fatty acids and minerals.

The quality of fishmeal, however, can be affected by different factors.

 

Results of this study suggested that salmon meal stored for up to 12 months at 30° C tended to show protein degradation. The study did not find any significant effect of the different fishmeals on growth performance, feed utilization or the nutritional composition of shrimp muscle.

Therefore, the quality of shrimp feed was not downgraded when 15% of the fishmeal was included in a diet under current testing conditions.

 

However, the observation might have been different if a higher level of the aged fishmeal was tested in the diet and also if it was tested with shrimp of different sizes. A further study with a longer feeding trial will be needed for a more complete evaluation of the nutritional quality of aged fishmeal.

 

Many studies have shown the quality of fishmeal is affected by raw material freshness as well as the species of fish and processing conditions used to manufacture the fishmeal. Different responses to the quality of fishmeal have also been attributed to the species being tested and their size or life history stage.

 

Furthermore, management of the finished meals is critical for the quality of fishmeal, which is susceptible to oxidation. Both rancidity from lipid oxidation and the presence of biogenic amines produced from protein oxidation affect fishmeal quality.

 

Responses and sensitivity to the effects of oxidized fishmeal are different for different species of fish and shrimp. For example, cadaverine and putrescine act as chemoattractants for freshwater prawns at 2,000 mg/kg in diets.

Putrescine was found to adversely affect both feed intake and growth of rainbow trout at a concentration of 13,300 mg/kg diet. Therefore, evaluation using a growth trial is necessary to evaluate the quality of a fishmeal in addition to data representing the degree of oxidation based on chemical analysis.

 

Source http://www.thefishsite.com