Feeding frequency plays a key role in regulating feed intake, growth and faecal discharge. Optimal feeding frequency not only promotes better zootechnical performance, but also reduces production costs and environmental impact.
1. Introduction
The demand for food, especially that of protein origin, has grown as a result of the increase in the world population, and the aquaculture has met part of this demand due to its expressive growth, showing potential to overcome this problem, providing high-value proteins. In this context, O. niloticus is the third most produced fish species in the world corresponding to 8.3% of production and the most produced in Africa, which occurs because the specie meets the demand for greater production in small spaces, this reduces the production cycle, and it is rustic and easy to reproduce, making it widely studied, with the main focus on improving the efficiency of fish farms.
Therefore, feeding is decisive for the viability of these systems, as it represents between 40 and 60% of the total costs and can reach 70%. It is considered that the influence of diet on growth is not limited to the choice of ingredients that will compose it, the frequency with which it is offered also alters the utilization rate of nutrients.
In this way, feeding frequencies vary between the species, production systems, and stage of development in which the fish are. Fish must have access to food in order to be satiated; however, if there is overfeeding, the excess raises costs and worsens feed conversion ratio and there will be an increase in costs. As for the species, in omnivorous with small stomachs, such as O. niloticus, the search for food occurs more frequently due to their limited storage capacity, not being able to consume enough in smaller frequencies like other carnivorous species or larger stomach species. As for postlarvae and fingerlings, as they have a more active metabolism, their digestive tract is not fully developed, and they seek food more often than juveniles, so feeding at the ideal frequency favors growth and optimizes the use of the feed. According to study of Fattah et al. (2013), increasing feeding frequency for tilapia may increase the chances of ingestion and feeding behavior, improving swimming behavior, and can reduce aggressive behavior. However, the ideal feeding frequency for tilapia fingerlings has not been established.
Regarding the organism of these fingerlings, more specifically the liver, where the processing of food occurs, it has a limited capacity for this, and its tissue can be compromised when its capacity is exceeded. This fact explains why overfeeding (high frequencies) can reduce feed utilization, worsening feed conversion ratio, leading to accumulation of fat and waste of nutrients (rich in phosphorus and nitrogen), impairing economic performance, and increasing environmental impact.
Therefore, it is necessary to investigate the feeding frequencies with the aim of evaluating their effects on fingerlings, as this parameter impacts the intake and growth, feed conversion ratio, and water quality.
2. experimental design
The experimental design was completely randomized, evaluating six feeding frequencies (4, 5, 6, 7, 8, and 9 times a day) with four replicates; the experimental unit was composed of a box containing ten fingerlings. Five hundred fingerlings of the same spawn were acquired from a commercial fish farm called Dal Bosco Fish Farm, in the region of west Paraná, in the municipality of Toledo (near of the site of the present study) and transported to the laboratory in isothermal transport boxes with constant oxygenation. Afterwards, their mean weight (0.793 g) was determined, distributing the fishes in 24 boxes and keeping the mean weight of them in g. The duration of the feeding trial was 30 days.
Study results
According to the results of this study, frequencies F5 and F6 are the most suitable for tilapia fry production among those tested, with the greatest weight gain (WG) and final biomass (FB) occurring when tilapia were fed between five and six times compared to feeding frequency F4, and the gain not differing significantly between the highest frequencies (seven, eight and nine times).
Furthermore, it can be seen that treatments F5 and F6 had the highest consumption, a result that can be corroborated by their greater weight gain, whereas According to Tian et al (2015), low feeding frequencies reduce growth, but high frequencies increase the load and reduce feed utilization.
Conclusion
Feeding frequency interfered with fry metabolism, so that fish fed between five and six times a day achieved greater weight gain, and considering this factor and feeding costs, these frequencies showed the best economic responses.
Reference (Free access) :
Aldo Felipe Fava, Gildete de Souza Bezerra, Dacley Hertes Neu, Fabio Bittencourt, Altevir Signor, Kerolay Valadão Carvalho, Ricacio Luan Marques Gomes, Wilson Rogério Boscolo, «Effects of Feeding Frequency for Nile Tilapia Fingerlings (Oreochromis niloticus)«, Aquaculture Nutrition, vol. 2022, Article ID 1053556, 10 pages, 2022. https://doi.org/10.1155/2022/1053556
