The feed efficiency of fish
Feeding fish often estimate the so-called feed ratio showing the amount of feed (in kg), should eat fish to give 1 kg of gain.
For example, if they say that feed efficiency of sunflower meal is $ 4, this means that in order for the fish increased weight by 1 kg, she had to eat 4 kg of this cake.
In other words, feed coefficient expresses the ratio of eaten to increase.
Sometimes to determine the effectiveness of feeding favour by not feeding ratio, and the so-called forage payment, or, in other words, the feed consumption per unit growth of fish.
This indicator expresses the ratio between the amount specified (and not eaten, as in determining the feed ratio) in the feed pond to increase fish.
The latest from economic point of view is more correct .
Payment of feed cannot be identified with the ratio of forage, as is sometimes done .
Indicators feed ratio will always be lower than the payment of food, not all food as defined in a pond, eaten by fish, some feed (due to various reasons) always lost.
Total feed ratio and payment of the feed, the lower their performance, the greater the effect of feeding, i.e. feed between the index (and the payment of feed) feed efficiency observed inverse relationship.
Normovolaemia and payment of feed depend on the ratio in the feed of different groups of nutrients (proteins, fats, carbohydrates), vitamins, mineral elements, etc. in other words the nature of forage fish, which it fed, method of feeding etc.
Even for the same feed and same type of fish these indicators do not remain constant.
They depend on the age and physiological state of fish, methods of forage preparation and distribution, preparation of ponds the temperature and hydrochemical regimes, the natural fish productivity, forage quality (fresh or it’s stale), and many other reasons.
So, at a young age, for example at the first and second year of life, fish using the same food, are growing much better than, say, the third and fourth year.
Therefore, young fish feed conversion ratio and payment of feed (in equal conditions) will always be lower (better) than the older.
In healthy fish, these figures will always be better than a sick or weak.
Well prepared food eaten better and lost considerably less than poorly prepared.
Therefore, the performance of feed ratio and feed payment in the first case will be much better than the second.
If you set the feed the fish several times a day in small portions, the rate of feed ratio and feed payment will be significantly better than the simultaneous feeding of large quantities of the same feed.
Feeding on special devices (feeders) provides a lower (better) values of feed ratio and feed payment than giving feed directly into the water.
In the latter case, unavoidable significant loss of forage even at very good cooking.
With a significant increase (or decrease) the temperature of water compared to optimal for this species of fish feed conversion ratio and payment of feed will be increased, and the efficiency of feeding decrease accordingly.
With the deterioration of the gas regime of the ponds increases the size of the feeding ratio, as the decrease in the content of oxygen in water drastically reduces the consumption of food and its digestibility.
You socioproductive in ponds with good gas mode the feed conversion ratio is always lower (better), and the efficiency of feeding is higher than in less productive ponds.
In the organization of feeding fish make a plan , which take into account the condition and preparation of the ponds, the quality and condition of the stocking material, the presence of certain types of fodder in the farm and the possibility of their use in fish, the possible density of fish in ponds, increasing fish yield per unit area due to the compaction of planting and feeding.
It should be remembered that the best results are obtained by feeding fish in ponds highly productive, fully discharge, free from thickets of hard surface and soft abundance of underwater vegetation, with slabozailenny bottom, without weeds and predatory fish.
The ponds do not drain, overgrown and silted, full of weed and predatory fish, feeding is unprofitable.
The total demand for feed is determined on the basis of the planned increase in fish yield due to feeding and the feed rate (or payment) of the feed.
For example, the natural productivity of the pond is 200 kg/ha, and is expected to increase the fish yield by feeding sunflower meal, feed conversion ratio equal to 4, up to 1000 kg/ha.
The question is, how much of this meal for feeding fish in a pond of 10 hectares? If 1 ha of pond area increased the fish yield by feeding kg is 800 (1000-200), with 10 ha it will be 800X10, or 8000 kg.
Then sunflower oilcake to ensure this growth for the entire season will need 8000X4, or 32 000 kg.
If you know the consumption of feed for each month, it is easy to calculate and average daily villas on the entire pond and on a separate feed.
It is best to feed the fish feed mixtures, which (when properly utilized) is always more valuable in terms of the content of individual nutrients (proteins, fats and carbohydrates), minerals and vitamins than a separate feed, however good they may be.