Protein is a major cost in aquafeed as aquatic animals have high protein needs compared to terrestrial animals. Furthermore, fishmeal is very often used in fish and shrimp diets. Its price increases faster than other ingredients. Over a 25 years period, fishmeal price increased by 350 percent, while soybean increased only by 150 percent (Source: Indexmundi).
In this situation, feed producers need to be careful when using protein sources to fulfil the needs of the animals. First from an economic point of view, but also regarding the quality of this protein. Indeed, protein itself doesn’t mean a lot, protein could have a low digestibility (because of intrinsic composition of an ingredient, or suffer from processing for eg), it could also be unbalanced. This could result in lower growth of the animal. This brief article will help you save some cost on your feed while safeguarding its quality.
The quality of feed relies on the quality of its ingredients
“Quality inputs lead to quality outputs”, this saying is also true for feed. If one doesn’t watch what they buy or doesn’t handle it properly; even fish meal could be of a lower quality than vegetable ingredients. It depends on the raw material quality, is it processed fresh, how is it cooked and dried, extracted, protected and finally stored? These key points are similar for quite a lot of ingredients. Therefore, analysis can give a good overview of the quality of ingredients. Specific criteria exist for each raw material.
Some important analysis to ensure the quality of several ingredients
For example, fishmeal quality could be impacted before processing if the fish are not stored properly; this will be evaluated by the biogenic amines values which are the result of degradation of specific amino acids. Processing could also have an impact on the quality of the product by overcooking; this could be evaluated by oxidative parameters. Overall quality of the proteins within fishmeal is often evaluated by pepsin digestibility.
Similar parameters could be analysed on animal meals such as poultry meal, meat and bone meal. For soybean meal, different tests exist such as the urease test and anti-trypsic factors. They will analyse the processed well-cooked protein, with enhanced digestibility, which, if subject to overcooking, may result in lower digestibility of certain sensitive amino acids such as lysine. Free lysine could also be an indicator of the quality of DDGS. The main risk with these products is overcooking which reduces the overall digestibility.
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The Aquaculturists
