The profitability of aquaculture, especially the fish segment, is deeply related to the type of feed used. A balanced diet rich in proteins that contain all the essential amino acids will lead to a greater development and growth of these animals.
Because of that, for the formulation of feeds for fish, it is necessary to use ingredients that are a source of this type of nutrient and that present high digestibility, guaranteeing complete use by the animal’s organism.
Feather meal, poultry meal and pork protein are part of a category called premium meals, used as an ingredient in the formulation of feeds for fish and other animals. Premium meals are balanced, high digestibility protein sources.
In this post we will explore the premium meals as ingredients for the formulation of fish feed, presenting the advantages of its use and the impact of such protein sources on fish nutrition.
The importance of proteins for fish diet
One of the most important macronutrients for the fish organism are proteins. Because they are part of the muscle tissues, the ingestion of proteins that contain an adequate balance of amino acids will be one of the determining factors for a good growth and development of the fish.
When ingested, the proteins are hydrolysed into amino acids, which will be used for the synthesis of new proteins, with consequent expansion of muscle tissue.
Among the amino acids available in the nature, a part of them corresponds to the essential amino acids. These are not synthesized by the body and must be necessarily acquired through diet.
Therefore, it is fundamental that the fish feed has a balance that contemplates all the amino acids that are essential for their development. This factor should be taken into account when formulating feed for this type of animal.
Another aspect is the use of raw materials containing proteins and amino acids with high digestibility.
In foods with low digestibility, nutrients are not absorbed by the body and therefore, do not fulfil their vital functions, limiting the feed conversion rates of the system as a whole.
Bird feathers are co-products of the chicken processing industry and can be used for the production of feather meal.
Widely used in salmon fish feed in North and South Americas, feather meal is one of the viable substitutes for fishmeal, which is quite costly.
However, there is still some resistance in some parts of the world regarding the use of this ingredient, due to a belief that this material has proteins of low digestibility.
This idea must be demystified. For this, we need to first understand why the meal of feather has this fame.
Keratin is the main protein that constitutes feathers of birds and may correspond to 80% of the total protein content in this raw material. However, the fish organism is not able to digest keratin in its native form.
Nevertheless, the processing of the feathers, through the application of heat and pressure, for its conversion into a meal, modifies the keratin structure.
In this process, the keratin disulphide bridges are broken down, making proteins and amino acids available for use by the fish organism. The temperature of the process is a critical control point.
Very high temperatures form complexes of different groups of amino acids that are not digestible by the animal. In addition, elevated temperatures cause protein and amino acid degradation, decreasing the nutrient value of the ingredient.
The only amino acids that are not present in expressive amounts in feather meal produced at low temperatures are lysine and methionine. This deficiency can be balanced by adding blood to the feather meal.
Advantages of Using Feather meal
Besides being cheaper than fishmeal, some studies show that feather meal may have a comparable efficiency to its counterpart.
A study compared the efficiency of fish meal and feather meal in shrimp and tilapia feeding. Each group received a feed based on one of the two meals, with the consumption and weight gain of the animals being monitored.
At the end of the experiment, none of the species presented negative effects in relation to growth with the substitution of fishmeal with feather meal. Both were equivalent in performance.
The feather meal for the formulation of feeds needs a strict quality control to guarantee its effectiveness. It is important to choose a supplier that uses fresh and controlled quality raw materials for its production, as well as mild processing conditions.
In this way, a feather meal with proteins of high digestibility is guaranteed that will positively affect the profitability of fish farmers.
It is already possible to find in the market feather meal and feather meal with blood. Produced from fresh raw material, they are processed by pressure cooking, fulfilling all the requirements of a protein rich ingredient, contributing to a good growth rate in fish and other animals.
Other premium meals
The poultry meal is another viable option for the replacement of fish meal in fish feed. The viscera are co-products of the poultry slaughtering industry and are used as raw material for the production of this ingredient. The poultry meal has all the amino acids necessary for the proper development of the fish.
For carnivorous fish, low-ash meal is preferable because it has better palatability, high protein content and similar energy content to fishmeal.
For all these characteristics, some studies suggest that meals produced from poultry by-products may be partial or total substitutes for fishmeal, with no impairment in performance. In addition, a substantial reduction in production costs is achieved.
A study used poultry by-product flour to partially replace fishmeal in bass fish feed. The research was done based on the digestibility of nutrients and it was proved that a replacement of 35% by the meal of poultry by-products allowed a performance equivalent to the fish that only consumed the fish meal.
Another experiment also studied this same type of substitution in the feeding of snapper fish. The researchers concluded that the use of poultry by-products meal in the proportion of 25% in fish feed resulted in a growth similar to that of fish that consumed the control diet with 100% fishmeal.
Pork protein meal
Another premium meal that emerges as an alternative to fish feed is pork protein meal.
This ingredient is produced by cooking, pressing and grinding of skin and swine mask in natura and pork crackling. The meal obtained from by-products of pig slaughter is also a rich source of essential amino acids and proteins, which has high digestibility. The pork crackling, for example, has 14 g of protein in a half-cup serving.
The consumption of this ingredient will provide all the amino acids necessary for the good development of the fish.
Both the pork protein meal and the poultry meal in standard and low-ash versions can be purchased commercially. Produced in mild temperatures that do not affect the amino acid content and produce a better digestibility characteristic, these premium meals are excellent sources of protein from a fresh, high quality raw material.
Fish feed needs a supply of proteins and amino acids essential for healthy animal growth and development, ensuring more profitable business for fish farmers.
Fish meal is a standard ingredient used in this type of feed; however, its high cost calls the attention to the need of looking for more economical alternatives, without affecting the productivity of fish farming.
For it, premium meals derived from poultry and pork slaughter by-products are considered viable options. With the correct type of treatment and handling of raw materials, it is possible to produce meals that contain all the essential amino acids and that contribute significantly to a good development of the fish.
Knowing each one of these meals and researching information about reliable suppliers is of fundamental importance for formulators who work in this segment. Choosing quality inputs will ensure high digestibility proteins that will perform their vital functions without any kind of loss.